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Ground Source Heat-Pump Demonstration Contract NO. AEC81-005-1 1983
GROUND SOURCE HEAT-PUMP DEMONSTRATION (Contract No. AEC 81-005-1 from the Alaska Energy Center) August 1983 Prepared by: H.C. Stenbaek Nielsen Geophysical Institute and John Zarling Department of Mechanical Engineering University of Alaska Fairbanks, Alaska 99701 Abstract Two commercially available ground-coupled heat-pump systems were installed on the University of Alaska, Fairbanks campus in fall 1981 to investigate the feasibility of using heat extracted from the soil for home heating. Such systems are successfully used in Scandinavia. The heat-pumps have been in operation during the last part of the 1981/82 heating season and have worked well. The results indicate that in a typical Fairbanks installation one can expect a C.0.P. of 2.0-3.0 (i.e., for each kWh purchased power the pump will deliver 2.0-3.0 kWh worth of heat). The thermal response of the soil to the heat extraction has been favorable. However, with only one and one half years of operation we do not have data enough to definitely show that permafrost is not created by the heat extraction. Table of Contents INTRODUCTION COP emer cece errr e reer ersccsceersevercccccssssesecesessessceseees BASIC PRINCIPLES OF A GROUND HEAT-PUMP INSTALLATION as HISTORICAL BACKGROUND COO m eee emer ee rene ees nnrseeee esses sessesesesccsssece Larger installations ome emcee eee e eres nee neces essen ssseesccscsecece PROJECT OBJECTIVES POR e eee emer e eer e renner n rs sreseneeeeesssseeeeececesseee Change of project plans Cem meee cere ere nnee nee ec reser ceseseeescseuee TEST INSTALLATION PPO e ee eee weer eee e re eerreeen saree rennnsscsereeseesssseces Temperature probes Cr Flow meter Oem meee reece rere rere nasser esen esc sssesseeseessssccees BTU meter a Computer modeling program a Data collected Peer meee eee r nena ceeeeeerrresseneseseesseesecseseecee EVALUATION OF DATA a Cantherm DUO-500 Cece reece reer ere recereeeeeessseseecescesecesesceces Command~Aire SWP-541 Cee meee meee cree reece eran sceseessesenecseceeeee Soil temperature Too meee were e ces crreeeseresscsseseeescscesececece CONCLUSIONS COMO eee eee rere ree erere nena nase reeeeeseerereeesseesceseccsscoce REFERENCES I Ie APPENDIX I: Appendix II: Appendix III: Appendix IV: Five Year Project Plan DUO-500 Owner's Manual Installation Service Maintenance Manual for SWP/H Water/Air Heat Pump Biweekly Soil Temperature Profile 1i 10 22 24 24 24 25 28 29 33 33 39 44 INTRODUCTION The purpose of the project was to investigate the feasibility of using ground-coupled heat-pump systems for residential heating in Alaska. Such systems are successfully used in Canada, in the central Oklahoma region of the U.S., and in Northern Europe, but are still relatively unknown in the U.S. ‘The main source of heat is solar energy stored in the ground. The heat is collected by a brine circulating through a buried pipe and is upgraded by a heat-pump for use in residential heating. The temperature of the ground at a depth of a few feet is relatively constant year-round. Therefore, a ground- coupled heat-pump system is unaffected by the seasons and, in contrast to many other alternate energy systems, can deliver heat also during the depth of winter. This ability makes it a potentially valuable alternate energy heating system for use in Alaska, and several individuals and government agencies have in recent years had interests in such systems. The project reported on here was funded by the Alaska Energy Center. BASIC PRINCIPLES OF A GROUND HEAT-PUMP INSTALLATION ee RB SAR BALLUN The principle of the heat-pump operation is the basic vapor compression refrigeration cycle. Figure 1 shows an installation schematically. On our installation heat from the ground was collected by a brine solution circu- lating in plastic pipe buried in the ground and delivered to the evaporator side of the heat~pump unit. Then, inside the evaporator a refrigerant is boiled, extracting the heat required for vaporization from the brine. The vapor is then compressed and thereby heated. In the condenser, the compressed vapor liquifies, releasing heat to the medium around the condenser, in our case water or air, which then distributes the heat throughout the house. The Condenser and Heat Exchanger Figure 1. Schematic of a heat pump installation. The principle is the same as employed in refrigerators. The liquid refrigerant boils off in the ground coil,’ extracting the heat for its evaporation from the ground. The vapor is then compressed and thereby heated. In this example, the home is heated by ciculating air passed over the condenser by a fan. The unit could be used for cooling during the summer simply by reversing the circulation of the refrigerant, letting the ground coil function as the condenser. refrigeration loop is closed with the liquid refrigerant passing through a pressure reduction valve and back into the evaporator. The cycle described above may be reversed, in which case the unit would take heat from the house. This might be of interest during the summer if air conditioning is required. The heat removed from the house would then be pumped into the ground. In order to move an amount, E, of heat energy from one reservoir, the ground, to another at a higher temperature, the home, work has to be done by the heat~-pump. The electrical energy, P, consumed by the pump is also converted into heat. Thus, for the consumption of the energy P, we obtain the energy (E + P) as heat to the home, where E is free of charge. The amplification n = (E + P)/P is called the coefficient of performance, C.0.P., of the heat-pump. Under theoretical Carnot conditions, the C.0.P. can be calculated by using the temperatures of the evaporator, Toold? and the condenser, Tarn: 0 C.0.P. = Toa ae Toole: 9 Faaa noe Tora’ = ous &) ~ om 1a’ © Note that C.0.P. depends on the absolute temperatures (°K) only; (thus the extraction of heat is not prevented because the soil temperature is below freezing). If, as an example, T g = 60°C and Tj -10°C, we calculate a C.0.P. of 4.8. This is the theoretically maximum energy gain obtainable by the heat- pump. In reality, the thermodynamical processes are not ideal, which together with unavoidable mechanical losses will decrease the C.0.P. Our experience is that little more than half of the theoretical value may be obtained in practice. The heat collected from the ground is basically stored solar energy. The true geothermal heat flow in geothermally nonactive areas is only of the order 3 of 75 n/m? (300 watts/acre), wholly insignificant in this context. At higher latitudes, as indeed is the case for the interior of Alaska, this means that the heat extracted during the winter months cannot be replenished before the following summer. HISTORICAL BACKGROUND The idea is far from new. In 1852 a Scotsman, William Thompson — the later Lord Kelvin - argued the wastefulness Se chaentas coal for heating purposes. Instead, he suggested, the coal should be used to operate a heat pump. The heat-pump could then upgrade energy taken from a suitable available source, for example the air, and thus the total heat provided would be the heat from the coal plus the heat collected from the air (Thompson, 1852). However, the idea had to remain no more than an idea since the necessary technology was not available, and would not become available for almost another century. Several systems were built in the U.S. during the 1940s and 1950s, and some early installations were reviewed by Penrod (1949). In Canada several systems were tested by the Ontario Water Authority. A system installed in 1950 that is still operating in Hamilton, Ontario, was featured in a National Film Board of Canada short documentary, "Bill lLoosely's Heat Pump." Individual units were constructed in Europe, and some 11 years of data for a Danish system were reviewed by Stenbaek-Nielsen and Sweet, 1975. Because of the low energy prices prevailing through the 1960s and early 1970s, ground-source heat-pump systems remained novelties and were not developed commercially. However, because of the generally higher energy prices prevailing in Europe, several manufacturers there kept an interest in such heating systems; so when the first “energy crisis” came in 1973, it was not long after that these heating systems were commericially available there. The idea caught on, and there are presently over 15,000 single-family homes in Scandinavia that are heated with ground-coupled heat-pumps. Naturally, there are also quite a number of manufacturers of such heating systems. One of the leading firms is AGA-Thermia in Arvika, Sweden. AGA- Thermia has been involved in the development and testing of ground-coupled heat-pump systems for over ten years, with part of the development done in cooperation with various Swedish government agencies. Today the factory offers a range of system sizes, all sold with an unconditional five-year warranty - which is good evidence for the technical maturity of their system. The AGA-Thermia systems are also produced and marketed by Canthern, -Ltd., in Montreal. Each ground-coupled heat-pump installation is virtually a _ unique design. Most manufacturers have developed a_customer questionnaire that can efficiently provide the firm with the relevant data about soil, lot size, house size and other significant items. If an installation is deemed possible, a site visit will be made and a design and price quote is then prepared for the customer. Larger installations In Sweden there are several subdivisions which are heated by ground heat. One of the earliest ~ and most publicized - is in South Surte outside GSteborg. It was built by the Cooperative Building Organization of the Swedish Trade Unions in 1976. Of the 103 homes in the subdivision, 88 were equipped with AGA-Thermia heat-pumps, while the remainder have conventional electric heat for comparison. Each of the 88 homes has its own separate heating system consisting of a heat-pump unit located indoors and a ground pipe array in the garden. In some places the ground pipe has been laid in adjacent community garden areas. The ground source heating system is the sole source of both heat and domestic hot water for each house throughout the year. The soil is clay with a relatively high moisture content, and there have been few frost problems. The performance of the heating system in the subdivision is monitored by Chalmers Institute of Technology in G&teborg, and the Swedish Institute of Technology is evaluating the data. A more recently built subdivision equipped with heat-pump heating systems is in Orsa, in mid-Sweden (Figure 2). The climatic conditions here are more like those in Alaska; the yearly average temperature is 3-4°C, with average extremes of 16°C in July and -9°C in January. Although this is still miider than Fairbanks climate, the soil temperatures are comparable, 5°C in Orsa and 2°C at our installation in Fairbanks. As is the case in South Surte, the soil is very moist and some of the ground grids are below the level of the ground water. There has been some frost action in the soil, but no serious problems have been encountered. PROJECT OBJECTIVES The ground-coupled heat-pump demonstration project was initiated in February 1981 with an expected duration of 3-5 years. It was sponsored by the Alaska Energy Center and the level of effort was anticipated at $100,000 per year. The original proposal outlined a five-year project plan (Appendix I). During this period we would test various types of installations and develop design guidelines for their use in Alaska. 1 . 2 \ Figure 2. Layout of the ground grid for the subdivision in Orsa, Sweden. Nineteen of the 22 one-family homes in the development are heated by ground heat. The pipe grid for each home is 400 meters long; the pipe is 40 mm outside diameter. The soil is very sandy, and the water table is relatively close to the surface. The pipes are buried 1-3 m deep in very sandy soil, and 13 of the houses have their grids below the level of the J ground ‘water (darker grids to the right and in parking lot). The remaining grids are 0.5 to 1.5 m above the ground water. As with the South Surte development, this installa- tion is being monitored to obtain performance data. D 7 There were already several types of ground-coupled heat-pump systems on the market. In principle, all of these should with little or no modifications be usable also in Alaska. The available performance data and design guide- lines were developed for less severe climates and warmer soils than prevail in most of Alaska and may therefore not be directly applicable. The most serious uncertainty is related to the soil temperature, which in a typical Alaskan installation would be near freezing. This presents a number of problems that have not, to our knowledge, been addressed directly elsewhere. Will repeated freezing-thawing of the soil threaten the structural integrity of the system? How will the extraction of the heat affect surface vegetation? How well does the soil recover thermally after both short periods of heat-extraction (a cold spell) and following an entire heating season? (Note: the heat extracted is heat which entered the ground from the surface during summer, i.e., it is ultimately solar heat). Can heat be stored in the ground in summer and held for use in winter? To check the originally proposed program and, more importantly, to avoid duplicating any work we contacted, during spring 1981, other groups in the field. We gathered information from Oklahoma State University and Brookhaven National Laboratory, the leading groups in the United States; from the Technological Institute in Copenhagen, Chalmers Institute of Technology in G8teborg, and Uppsala University, among the leading research groups in the field in northern Europe; and AGA-Thermia, the leading ground-coupled heat- pump manufacturer in Scandinavia. The material received indicated that our original aim was correct. The main problem to investigate was the thermal response of the soil and the heat- pump performance. The overall aim of the project (as it appeared in summer 1981) could be expressed in the following: 1) To understand the response of cold soils to heat extraction. 2) To demonstrate and gain experience with different heat-pump systems. 3) To develop safe and reliable guidelines for the design and use of ground-coupled heat-pump systems in Alaska. 4) To provide cost/benefit analyses of various designs. From our contacts with other groups we were very encouraged to learn that frost action in the soil would presumably not be a severe problem and we decided, in consultation with the funding agency, to install two units already the first year, so that experience for different models and modes of operation could be gained faster. It was quite clear to us as well as the funding agency (the Alaska Energy Center) that in order to investigate the long-term effects on the soil the project would have to be continued for several years. In practical terms the question is are we creating permafrost? Without an answer it would be highly unlikely that any industry would consider the manufacturing or marketing of ground-coupled heat-pumps for use in Alaska. Change of project plans With the demise of the Alaska Energy Center by legislative action in June 1981 the project was transferred to the State of Alaska Department of Commerce, Division of Energy and Power Development which was to see the project to completion. Also sufficient funds for its completion were provided. In July 1982 DEPD decided that it was only obligated to fund the contract for the first year entered by the AEC, but would provide an additional $24,700 to “complete” the project by summer 1983. The additional money was to cover expenses already incurred from February 1982, when the first-year contract expired plus the operation of the heat-pump facility through the winter 1982-83. There would not be money for any analysis of the data. This obviously left void most of the original intent of the project, but it provided for one full year of data from the facility, which were valuable for an assessment of ground-coupled heat-pumps and, perhaps more significantly, the detailed soil temperature data may be applied to a number of other research problems presently underway. Because of the more general interest in the soil temperature data we have prepared these data into publishable form. A summary of the data is included in this report. TEST INSTALLATION It was originally proposed to locate the test installation at the University's Musk Ox Farm about three miles from campus. We later secured permission to use an equally suitable site on campus which obviously is more advantageous in terms of access. The site is a grass-covered south-facing field adjacent to the Arctic Health parking lot and opposite to the Geophysical Institute on the West Ridge of the University of Alaska, Fairbanks campus (Figure 3). The site has power and we were able to obtain use of a 10 x 30 foot ATCO trailer to house the installation.. The trailer was on loan from the Institute of Arctic Biology. 10 Figure 3: Views of the test site on the West Ridge of the University of Alaska, Fairbanks campus. The heat-pump and data recording equipment were located in the trailer located at the corner of the parking lot. The University ski trail system crosses the test site and the packed snow on the trail would, in spring, be the last to melt as evident in the top picture. iL Purchase of equipment and installation commenced in early July 1981. Delays due to both shipping and to various equipment problems were encountered, but the ground piping network was finished by early September, just before the first snow fell, and the installation of the two heat-pumps and the data logging system was completed in mid-December. The ground grid consisted of four 500-foot 1-1/2" high-density polyethylene pipe sections (see Figure 4 and 5), in which a brine (a 25% calcium chloride solution and a corrosion inhibitor) was circulated. The two sections in the south field were buried at a depth of three feet, while those in the west field were at a depth of four feet. Originally we had planned a depth of five feet, but it was learned that for installations in Sweden, AGA- Thermia, the leading Scandinavian manufacturer recommends depths of only two to four feet. The reason is that the soil can recover faster so that although the temperature at this smaller depth varies more from season to season, it is possible to extract more energy per unit grid length, which, because of the large investment in the grid, results in better economy. The soil at our test installation is Fairbanks silt. Part of the site has been backfilled, but the soil conditions appear to be fairly uniform across the site. The dry density of the silt varies between 80 1b/£t3 (1.27 g/cm?) and 97 1b/ft? (1.55 g/cm). The south field is more moist (16-20% of dry weight) than the oat field (8-14% of dry weight). This difference is most likely due to the fact that the Arctic Health Institute parking lot is draining across the south field. The two heat~pumps were installed in a 12 x 30 foot ATCO trailer on lease from the Institute of Arctic Biology (Figure 6). The units were connected to the buried pipe through a manifold which allowed us to select the number and configuration of coils associated with each unit (Figure 7). The two units 12 €T South Field : T.. Trailer 280! Arctic Health Parking SS ] Koyukuk Avenue North Figure 4: Layout of the 2000 foot pipe. The pipe was laid in 500 foot sections. The two sections in the south field served the DUO-500 heat-pump while the SWP-541 heat-pump extracted heat for the west field. 14 Figure 5: The 1 1/2 inch high- density polyethylene pipe came in 500 foot sections. The pipe was rolled out (top photograph) and placed into the trenches (bottom photograph). The grid was layed out such that pipe welds only had to be made near the trailer. Figure 6: Composite photograph of the two heat-pump units in the trailer. The horizontal unit to the rear is the SWP-541 air-to-air heat-pump. The compressor is to the left in the unit and the condenser to the right (normally the consenser was covered by an air filter). Behind the condenser is an air circulating fan and the warm air exits the units on the rear. The brine pump is seen mounted to the left below the heat-pump. The DUO-500 unit is standing to the front. The front and rear panels have been removed to show the different components. A schematic identifying these may be found in Figure 2 of Appendix II - the DUO-500 manual. The heat is distributed by a circulating water/glycol solution. To add sufficient thermal mass to the installation a 30-gallon barrel (lower left in the picture) was inserted in the water/glycol line, and the heat was dissipated in the forced air heat-exchanger to the right. Not visible in the picture is an exhaust fan mounted in a window. Despite this fan the room temperature often became excessive and the length of individual heat-pump operations had to be reduced. 15 16 Figure 7: Dis- tribution manifold for the brine lines. The mani- fold allowed us to put the four 500- foot pipe sections in almost any series or parallel conbinations. Figure 8: Distribution panel for data and heat- pump control lines which come into panel to the left, while the two cables on the right go to the HP-3054 controller and data-logger. The box to the left is the BTU- meter. were manufactured by Cantherm Ltd., in Montreal, Canada, and by Command-Aire in Waco, ‘Texas, respectively. The Cantherm unit (model DUO 500, 12 kV nominal capacity) was a liquid-to-liquid system modelled on the Swedish AGA-Thermia ground-coupled heat-pump series, while the Command-Aire system (model SWP-541, 16 kV nominal capacity) was a forced hot-air unit. Manuals provided by the factories for the two units are included in this report as Appendix II and Ill. Both units and the buried pipe grid were instrumented to give information about the thermal response of the soil to the heat extraction and energy transfer rates to the heat-pumps. Figure 8 shows the central panel through which all data and control lines were patched. All sensors were calibrated prior to installation. For the duration of the project, the DUO-500 unit extracted heat from the south field while the SWP-541 unit used the west field. Thus both units were extracting ground heat from 1000 feet of buried pipe. Routine operation of the Cantherm unit commenced on January 4, 1982. We did have some minor problems initially because of a leak in the compressor piping which required the system unit to be recharged with Freon. The Command-Aire unit was damaged in shipping. The type, SWP-541, was a new line of heat-pumps produced by Command-Aire and introduced on the market in fall 1982. Command-Aire preferred to exchange the entire unit rather than attempt to repair it and a new unit was received and installed in February 1982. The heat-pumps were operated and the data collected by an HP-3054 data logger. Because of power constraints both heat-pumps could not be on at the same time. While any sequence of pump operations could easily be programmed into the system, the general mode of Operation was to operate the pumps 17 alternately. The Command-Aire unit was started on the hour and half past the hour while the Cantherm unit was turned on at 15 and 45 minutes past the hour. Operation was restricted to a maximum of 12 minutes per cycle with the last three minutes devoted to storage of the data on magnetic tape. Thus each unit had a maximum duty-cycle of somewhat less than 50%. In terms of the thermal load of the ground this was compensated for by the shorter length of pipe: 1000 feet against various manufacturers' recommendations of more than 2000 feet for our climate conditions. The number of minutes of operation and the mode of operation could be entered or changed by keyboard entries on the data logger. The data acquisition system provided partially reduced data on system performance. For example, pump performance, ground soil temperatures, or vertical temperature profiles in the ground could be viewed in real time. More technical and programming details may be found in the report entitled: "Ground heat-pump: Operation and data acquisition software” which was submitted in March, 1982. The data recording system recorded data on heat-pump operation and soil- temperature data separately. For each operation of a heat-pump first the start time, unit (DUO or SWP) and number of minutes of operation were recorded and then every minute measurements were taken to document the pump performance. The parameters measured were: On both DUO and SWP units: Power consumption Brine temperature at inlet (T-brine in) and at outlet (T-brine out) Brine flow rate (F-brine) 18 On the "warm side” of the DUO unit: Water temperature at pump outlet (T-hot out) and at return (T-hot in) Water flow rate (F-water) BTU delivered by the water (BTU meter) On the “warm side” of the SWP unit: Air temperature at exit (T-hot out) and inlet (T-hot in) - (since the SWP unit is a forced air unit the inlet temperature would also be the room temperature of the trailer). Air flow (F-air) was recorded at 2000 cubic feet/min, the nominal capacity of the blower fan. Based on these measurements operating characteristics and heat flows may be calculated. For example, the heat extracted from the ground would be (Tprine in ~ T_prine out? *Forine *Cy rine? where Chrine is the heat capacity. Note that some redundancy was obtained on the DUO unit by the installation of the BTU meter. In addition, also the brine temperature along the buried pipe was measured, but only values at the start and the end of the pump operation were recorded. The soil temperature data were provided from a network of 68 temperature probes buried in the soil. Temperatures were measured to a depth of 20 feet within the probe grid as well as away from it. The probe locations are described in Appendix IV. The soil temperatures were recorded each hour. Examples of the data are shown in Tables 1 and 2. 19 €830119. pat TIM: MIN 00: 00: 54 7 70. $96 ™ pT FB TA 2-2 249 0.00 2ar3® BTAIR cyEa 39 228 10:10 B98 735 63:8 2.9 2.60 10:07 30:4 75a 3:30 1-@ 283 10:01 31!0 778 43:25 ig Fes 188s BES 730 468 “2 Bee ioioa 33:3 5:88 3:63 1200284 10:02 33:1 7:58 4°87 Tee 5 1.7 <2, Ti13 =i 3 TRO 22-4 21-3 -1.6 -1.9 -21 -1.4 -29 +99 1 9 1 9 | - - THES wh. 4 917 milo 9102 15 X17 OS Ih: 3 B32 23:3 213 =i? Ti? 1% 2h D830517. DAT TIME MIN OAL 00: 15:00 10 162. 216 : Ta DTB FB Te DTc FO GVEA Ae Rf 22 Bs GHP oes ot Of Ye 29 1:23 16:18 soit 2:38 4.43 4:93 9 ? 8 87 2:48 Jets 50:4 6:36 «4:49 «4:22 14 i 33 8§ 3:33 16:15 506 aag 4543) 353f ig 4 a7 8-3 1.67 16513 S05 44a 4:39 4.90 22 3 13 9-2 1-89 1614 51!0 449) 64:33 = 4-89 27 5 43g 8-3 425 tog Sire gap 34g 3 BS 31 3 gis O72 2-73 161k 53g 245) 4°49 4.91 36 2 338 Q-3 1.70 16:12 5156. S50 3°49 ; 3 433 OS 7. jet 51:7 ° B42 3:42 4:87 33 5 334 TBc =§: 3 9:3 -9-3 70.7 -0.6 -0.9 -0.9 -0.9 -0.3 -05 70.3 0.4 =110 -1:1 29:8 8:8 22:3 att 70:3 78:3 3:4 3-2 9-3 8:4 =8:3 =3:§ TB - Brine temperature (°C) sec - “Table 1: and was Difference between brine inlet and outlet temperatures (°C) Brine flow rate (gal/min) Temperature of air for SWP unit (°C) Temperature difference for the air at exit and outlet (°C) Power consumption from Golden Valley (kw) Temperature of the glycol for DUO unit (°C) Temperature difference of the glycol between exit and inlet (°C) Flow rate for glycol (gal/min) Temperature of the brine out in the buried pipes (°C) Volume glycol (gal) as recorded by BTU meter 1000 BIU as recorded by BTU meter seconds of operation when BTU meter was last incremented * note the gal, BIU, sec measurements should provide the same information as the FG and DTG data Examples of heat-pump data. recorded on January 19, 1983 (top line). was at 00:00:54 and the duration of the run was seven min. (second line). second set is an example from the DUO-500. 17, 1983 and the run was of 10 min duration starting at 00:15:00. 20 The top set is from the SWP-541 unit The start of the operation These data were recorded on May Table 2: FIELD TEMF: DATE:’11 FEB 1983 TIME: 18:00:00 T. OUT/IN “17.90 FAR FIELD ~.l 3.1 PARK.FIELD -6.7 1.7 WEST HOR “4.1 -.1 WEST VERT -5.3 1.4 WEST BETW 6.7. WEST PIPE th SOUTH HOR 1.0 26 SOUTH VERT -.1 2.6 SOUTH BETW 9.0 SOUTH PIPE “1.5 1.6 indicated in the printout. 86 22 -1.7 -1.6 21 ay o.0 24.3 77 1.2 2.5 4.3 4.4 85 -.9 +6 3.3 3.77 6? -5.0 -5.1 5 .5 57 -.4 -7 61 -1.2 5 29 -5.4 -.6 -.4 -.2 49 -8 +6 -7 6 37 1.0 3.5 41 1.5 1.8 2 -2.0 -2.1 -1.9 -2.1 Example of ground temperature data. The location of the probes are Temperature probes The temperature probes used were made and calibrated by Mr. R. Seitz (Instrumentation Services, Fairbanks). Figure 9 shows the installation of a Probe on the buried pipe. The probes all used a YSI 44007 thermistor. The relation between the nominal resistance, R, in Ohms and temperature, T, in °K is: iy At 4n (R) +C (2n(R))? where A = 1.2837744 (10)? B = 2.363444 (10) C = 9.24467 (10) ° Because of small variations in the characteristics, the temperature offset, AT, at 0°C (an ice bath) was determined for each probe. A total of 82 probes were used and the corrections were commonly of the order 0.1°C. The largest correction was 0.40 °C. The corrections were inserted in the data logging system and applied when the measurements were taken. The probes in the soil functioned well. We had some problems with the probes on the heat-pumps where brine would enter the probe and short it out. Redesigned probes installed in April 1982 alleviated this problem but these probes were very slow in response and we suspect they may not have read the temperature quite correctly. It appears as if the probe measurements were contaminated by heat conducted to the probes from the plugs in which they were 22 23 Figure 9: Thermal probe mounted on the buried pipe to measure brine temperature along the pipe. Top shows the size of the probe. To avoid possible leaks in the pipe we taped the probe to the outside of the pipe and then insulated to mini- mize contamination of the registered temperature by heat from the surrounding soil (bottom photo- graph). Also seen in the photo are data lines to other buried probes. mounted. We had new probes on order but had to cancel the order because of the funding reduction and associated reduction in work effort. Flow meter The flow meters used were RS 807A made by Rho Sigma. The unit is a rotary type which provides 200 relay closures per gallon flow. The manufacturer claims better than 3% accuracy at flow rates between 1 and 30 gallons/min. Our own calibration confirmed this. One of the three flow meters failed and had to be replaced, but otherwise they appear to have functioned well. BTU meter The BIU meter was an RS 805 system made by Rho Sigma. It consists of an electronic integration unit which monitors the flow with an RS 807A flow meter and the temperatures through two probes (type SPTB). The unit displays on two mechanical counters total gallons flow and 1000 x BTU delivered. The unit was modified to allow the data-logger to record the counters. The flow meter and temperature probes may be seen mounted on the wall to the left in Figure 6 while the BTU-meter is shown in Figure 8. Computer modeling program During the first phase of the project a large computer program was developed to model the heat transfer from the soil to the pipe. The program uses a finite difference method to solve the heat diffusion equation and 24 includes the latent heat of fusion. It was used to evaluate how data from elsewhere would apply to cold soil conditions. The program could run on either the Geophysical Institute VAX computer or on the University-wide Honeywell system. The program is now being used in other projects by the University's Department of Mechanical Engineering. Data collected Routine operation of the Cantherm DUO-500 unit started in January 1982 and the Command-Aire SWP-541 in March 1982. Both units operated for the remainder of the 81/82 heating season and through the entire 82/83 heating season. The heat-pumps were not operated during the summer to allow the ground to recover thermally. For the entire operation the DUO units were extracting heat from the south field while the SWP used the west field. The amount of pipe on each of the pumps was 1000 feet. During the 81/82 winter both pumps were operated at predetermined periods each run. For example, the DUO could be operated in 12 minute runs while the SWP ran six minutes. Generally, the DUO was operated for longer periods than the SWP to simulate different thermal loads on the soil. For the winter 82/83 the operational mode was slightly different. While the DUO was run for a constant period, which was set as high as possible to maximize the thermal load in the soil, the SWP was operated in a heat demand mode. In this mode the computer would adjust the length of each run relative to the outside air temperature. The adjustment was based on a total heat requirement for a 14,500 degree day year of 30,000 kWh. The 14,500 degree day year is the standard heating index for Fairbanks, Alaska. 25 Table 3. Monthly summary of DUO unit. Date Run Total Time El. Power Soil Av. C.0.P. [hr] [kWh] [kWh] 1982 JAN 807 134.5 655.5 824.4 2.3 FEB 863 147.4 675.9 730.2 2.1 MAR 1084 150.0 711.8 1094.9 2.5 APR 639 105.8 501.3 622.0 2.2 MAY 197 28.6 148.1 167.2 2.1 1982/83 SEP 127. 11.4 64.3 - 88.5 2.4 oct 550 75.5 403.5 541.7 2.3 NOV 1056 186.0 927.3 1308.7 2.4 DEC 630 108.9 531.1 804.0 2.5 JAN 1468 285.9 1362.9 2202.1 2.6 FEB 1335 266.8 1258.4 1917.0 2.5 MAR 1412 254.7 1208.0 1749.9 2.4 APR 1067 175.0 836.3 1113.4 2.3 MAY 1035 157.4 764.6 992.4 2.3 Table 3: Monthly summary of operation and heat extracted from the soil. The heat delivered by the heat-pump would be the electric power plus the heat extracted from the soil. The C.0.P.s calculated in the table are fairly low because of excessively high temperature in the trailer housing the installa- tion. The max in the C.0.P. in January 1983 is due to the exhaust fans which during the cold months was better able to keep the trailer “cool”. At more “normal” temperatures we would expect a higher C.0.P. 26 Table 4. Monthly sums of SWP unit. Date Run Total Time El. Power Soil Av. C.0.P. [hr] [kWh] [kWh] 1982 MAR 943 94.3 423.12 471.29 2.1 APR 643 102.9 480.17 517.15 2-1 MAY 197 39.3 191.84 186.90 1.95 1982/83 SEP 116 11.78 67.64 64.59 1.95 ocT 1086 163.6 816.45 1004.69 2.2 NOV 1301 144.1 691.16 983.07 2.4 DEC 1270 151.2 725.68 1053.54 2.45 JAN 1094 156.6 716.32 1003.7 2.4 FEB 9 MAR 6 APR 571 57.45 278.36 330.54 2.2 MAY 364 37.25 184.15 240.55 2.3 Table 4: Monthly summary for the SWP unit. From mid October 1982 the unit was in a demand mode where the length of operation was tied to the outside temperature. The assumed heating requirement was 30,000 kWh for a 14,500 degree day (°F) which is the standard for Fairbanks. The unit was inoperational during February and March due to a faulty brine pump. As for the DUO unit, the C.0.P.s are lower than they would be in an actual installation because of the high trailer temperatures. Z7. In Tables 3 and 4 we have summarized on a monthly basis all the pump data. The length of operation often had to be cut back because of overheating of the trailer despite the continuous operation of an exhaust fan. The warm facility resulted in a lower C.0.P. than would have been the case for more normal temperatures, but we accepted that since the main emphasis was on the thermal response of the soil to the heat extraction. Soil temperature data were taken every hour on the hour also during the summer when the pumps were not operated. There are some holes in the data coverage due to various equipment problems, but because of the very slow changes in the soil temperatures, these are without significance. Plots of soil temperature profile every two weeks for the duration of the project are shown in Appendix IV. All the data collected have been consolidated on one 2400 foot magnetic tape for processing on our VAX or Honeywell computers. EVALUATION OF DATA We decided to concentrate our effort on the soil temperature data and have gone through the data with the aim of quantifying the amount of energy extracted from the ground. The parameters determining the heat extraction are the change in brine temperature across the evaporator and the flow rate together with the (constant) heat capacity of the brine. These parameters were measured but because of the various probe problems and failures the values were not always reliable. However, the pérformance characteristics of the heat-pumps, if known, may also be used. Therefore, graphs of energy extracted from the brine, from the power net, and energy delivered as function of brine temperature and “hot-side" temperature (water/glycol on the DUO, air 28 on the SWP unit) were made and used during periods when the actual data were unreliable (or plainly wrong). Work done during the project's first year on the heat-pumps and their performance (Stenbaek-Nielsen and Zarling, 1982) formed a good starting point and the performance data only had to be updated with the larger body of data accumulated during the 82/83 heating season. We should note one complication in deriving the heat extracted: our thermal probes were fairly slow in responding to temperature changes and consequently would not record temperatures correctly during the first few minutes of heat-pump operation. To overcome this problem we only used data from the last part of each heat-pump run and then extrapolated to cover the entire run. This is not quite valid near start-up of the unit, but we believe the error thus introduced is small. Cantherm DUO-500 A technical description, as provided by the manufacturer, is given in Appendix II. The unit was installed in fall 1981 and after some minor problems were put into operation early January 1982. Although the installation was occasionally shut down for repairs or maintenance, the reason was rarely problems in the DUO unit itself. In the summer of 82, we were informed by the manufacturer that a brine pump designed for pumping a glycol solution was by error installed in our unit and that a calcium chloride solution, as is now more commonly used, might affect various seals and gaskets in the pump; repair, however, would be very easy. We did not find any problems during the one and a half years of operation although at tear-down of the system in May 1983 we discovered small deposits of calcium chloride indicating leaks. 29 During analysis it was confirmed that the brine pump performance had gradually deteriorated during the last four months. This was evident in the flow data which had slowly decreased from 20 gal/min to about 16 gal/min. (We had noticed the change in flow data earlier, but had thought it was due to an error in the flow meter, which we had had to replace earlier in the season). We do not have enough data to fully duplicate the factory provided diagram of the performance of the DUO-500 unit. Instead we have plotted in Figure 10 heat delivered as a function of temperature difference between water ‘ond brine. Because most of our data were obtained with brine temperature near O0°C the abscissa may also without large error be interpreted as hot water temperature. Since the power consumption of the unit is almost independent of temperature the figure clearly shows, as would be expected from theory, that better economy will result from cooler water temperatures. Some of our data points are plotted onto the factory provided graph in Figure 11. Our data appear to be in reasonable agreement with the factory data although the unit seems to draw slightly more power and the heat output is somewhat more temperature dependent than expected. Our results indicate that for Alaskan operations where the brine temperature for most of the year would be slightly below freezing, one can expect a coefficient of performance of 2.0-2.3 if heating is done with hot water baseboard at 55°-45°C. I¢£ instead, radiant floor slabs requiring a temperature of around 30° are used, a coefficient of performance of almost three may be obtained. 30 kW Te Energy extracted from the soil DUO-SOO0 1 4 of 35 40 45 50 20) Wark ould sg 0) Figure 10: Energy extracted from the soil by the DUO-500 unit as function of the difference between the hot water temperature (T-warm) and the brine temperature (T- cold). As expected from theory the larger the temperature difference the more work it takes to extract the heat and thus less heat is extracted. measured values 44 NEAT OUTPUT IN KW Ye oy + f—3) & oy ~ » wv = ~ Ss ° Se a ~ Ss = 4 Tove input POWER ee SS ; eq — a8 4 na Figure 11: Heat output and power consumption diagram provided by the factory for the DUO unit. Values measured on our installation are added. 32 Command-Aire SWP-541 Factory provided manual is found in Appendix III. The heat-pump started operating in March 1982. We have had no problems with the unit itself, but the brine pump (Bell and Gossett, 60-11 Centrifugal pump) failed in spring 1983 and a bearing had to be replaced. We are not certain about the reason for the failure, but suspect it related to the brine. The SWP heat-pump was not as well instrumented as the DUO. In particular we did not measure the actual flow of hot air, but used the factory provided nominal flow rate of 2000 cubic feet per minute which in our installation would presumably be an underestimate because of the lack of ducting. The design of the unit combined with our particular installation exposed the brine lines much more to the warm air than was the case for the DUO installation. Thus, although the lines and probes were insulated the brine temperature measurements were more susceptible to errors due to heat conducted to the probes from the outside. The potential error is very difficult to assess because of the lack of accurate air flow data on the warm side. Figure 12 shows a plot of heat produced. Soil temperature Because several researchers have expressed interest in the data, we have processed all the data and plotted the temperature profiles every two weeks for the duration of the project (Appendix IV). We collected data until fall 1983. Plots of the temperatures at a depth of three feet as a function of time are shown in Figure 13. 33 ve kW | ° a . Energy extracted from the soil SWP-54 1] L ul 4 cna | a aaa 30 35 40 45 50 55 fwakm | eet (dag C) Figure 12; Energy extracted from the soil by the SWP-541 unit. rexSQUTH FIELD CENTER reat GST FIELD CENTEK oN nem Z ~ ~~ fo ™ 7 / . : . f 4 \ ef ~ ‘ 4 Sk N\ f ~~ ~~. DN fe i J. cameneanns . WN FEB MAR APR May JUN JL AUG SEP OCT HOY EC JAN FEB MAR APR MAY WN JUL AUG SEP JAN FEB MAR APR MAY JUN JUL mS SEP OCT MOY DEC JAN FEB RAR APR MAY JUN JUL AUG SEP 1962 1983 1982, 1983 i rob tk FIELD re QXKING LOT eae 7 wy d ‘ \ ee —, wy é Nat a Jat FEB MAR APR MAY JUN JUL MUG SEP OCT MOY BEC Jan FEB NAR «PR MAY JUN JUL AUG SEP 1982 1983 Figure 13: Temperatures at a depth of three feet at various locations over the duration of the project. Surprisingly, the annual temperature variations in the west and south fields differ considerably. Further, the data from the south field and the undisturbed far field are very much alike while the data from the probes in the west field are more like those at the edge of the adjacent parking lot. The difference is presumably attributable to the difference in soil moisture content between the two fields. The parking lot is draining into the south field and excess water is carried over towards the area in which the far field data were taken by a drainage ditch. The temperature response of the soil to the heat extraction has been very favorable. Some temperature profiles from the south field recorded in early 1982 are given in Figure 14. The pipe is buried at a depth of three feet and the upper soil is generally warmer than at the far field probes. This was not the case the following year where the temperatures were more alike. We believe these differences are largely due to local annual variations in soil moisture content. Two temperature profiles from the south field are shown: one containing the pipe and one about four feet away. A very obvious effect of the heat extraction is that the profile containing the pipe should show a decrease near the depth of the pipe relative to the profile four feet away. This decrease is observable on the plots from February 13 and March 16; the depression is of the order of 0.5°C. Data from the following heating season, where the soil was subjected to heat extraction for the entire winter, are not much different. Instead of plotting individual profiles (which may be found in Appendix IV containing biweekly plots) we plot in Figure 15 the temperature extremes and the average for the entire heating season. A temperature decrease near the pipe, (top panels) relative to the profile four feet away (bottom panels) is just noticeable in the averages. Again the value is less than 1°C, which is very favorable for the operation of such heating systems in 36 LE DEPTH (feet) SOUTH FIELD. Pipe at a depth of 3 feet. Jan 2 82 Feb 13,82 Mar 16,82 Apr 21,82 20 2 Figure 14: Soil temperature (°C) as extraction. ~- ¢ -- ¢ -- 6 = 3: profile jin -------------------- : profile wa --- --- --- -- --: profile 20 20 function of depth (feet). Arrow points to the effect of the heat undisturbed soil (far field temperature) containing pipe 4 feet away (horizontally) from pipe | oe [od + r 1982-83 HEATING MONTHS 1982-83 HEATING MONTHS MAX, MIN, AND MEAN TEMPS MAX, MIN, AND MEAN TEMPS WEST CHT | goutH cnr TEMPERATURE cc) WEST BTW SOUTH BTW TEMPERATURE ¢€C) . ‘i TEMPERATURE ¢c) 4 MEAN 4 be MEAN Figure 15: Average soil temperatures and extremes for the 82/83 heating season. Alaska. Based on computer models and data from Scandinavia we expected a drop of 2-5°C near the buried pipe. We have not had a chance to analyze why the temperature decrease has been so small, but a contributing factor is presumably the insulating properties of the snowcover. One implication is quite clear: considerably smaller grids may be used which would significantly reduce installation costs (and thereby improve the economics). CONCLUSIONS The use of ground heat as a source of energy for home heating is feasible also in Alaska. The limited tests performed with two heat-pump installations, a Cantherm, a DUO-500 hot water system and a Command-Aire, SWP-541 forced hot air system, have given a coefficient of performance, C.0.P., similar to what is obtained elsewhere and the units have required little maintenance. The soil temperature, and thus the brine temperature, did not decrease as much as we had expected and the soil appeared to recover thermally very rapidly during the early summer. The reason is presumably the insulation provided by snow cover. This result is highly encouraging since it indicates that a smaller grid than the 2000-3000 linear feet required by Scandinavian design criteria, would be sufficient for an installation such as ours. A less rigid and maybe smaller diameter than the 1 1/2 inch high-density polyethylene pipe we used should be sufficient which together with a smaller grid would significantly reduce the installation costs. Also, a less concentrated brine may be used. (It should be noted that the Scandinavian design criteria does not assume a snow cover). Although the data for the one and one-half seasons that we have operated the system are encouraging, we do not know the long term effects on the 39 soil. With the heat extraction the soil should establish a lower average temperature and permafrost may result. Based on the available data the decrease appears to be small, but it is highly uncertain to what extent this is affected by annual climatological variations. There were no apparent adverse effects to the topsoil or the grass cover. It was expected that the greater cooling of the soil along the pipes would be visible by a delay in the melting of the snow but that was not the case. Figure 16 shows the west field on April 28, 1982. The snow melted uniformly across the field except for the base of the ski trail seen running diagonally across the picture. An economic analysis of ground-coupled heat-pump systems was done during the first year of the project and published in the Northern Engineer (Stenbaek-Nielsen and Zarling, 1982). This analysis is reproduced in Figure 17. Since then there has been some price escalation but not so much as to invalidate the conclusions reached: that in the Fairbanks area a C.0.P. of about three is required for a ground heat-pump system in order to be economically competitive with oil heat. (Resistance heating is clearly uneconomical). This, of course, is reflecting the fact that a significant part of the electricity is generated by oil-burning generators. In areas where hydropower contributes significantly to the power production electricity prices are more decoupled from oil prices and the price tends to be somewhat lower; this would improve the economics of a ground-coupled heat-pump system. It is also worthwhile to note that since hydropower is limited by the amount of water available at a given installation, the use of heat-pumps could in effect "stretch" the part of the power production used for space heating. This could be an important consideration in communities where power consumption is approaching the generating capacity. 40 Figure 16: View across the west field from the trailer. The picture was taken along the direction of the buried pipes on April 28, 1982. No evidence of the heat extraction is visible on the surface. The snow diagonally across the picture is the base of the University ski trail. If the cooling of the soil had been significant we would have expected a delay in the melting of the snow above the brine. F 41 SeVINUIEY AINAL TOD Current price estimates indicate that a heat pump heating system may be bought and installed for approximately $7000. - A breakdown of the costs involved with heat pump, oil, and electric resistance heating is given in Table 1. TABLE 1 Heating System Prices TABLE 2 15 Year Amortization* — Yearly Payments 8% 12% 16% _=_—— ee Resistance Heat $186.93 S$ 234.92 S$ 286.97 Oil Heat $490.68 S$ 616.66 $ 753.30 Heat Pump $841.17 $1057.13 $1291.37 “Based on initial system costs only (from Table 1). graphically. Figure 8 shows the compari- son among heat pump, oil, and resis- tance heating for the Fairbanks area. The asterisk marks last year’s energy price situation. With the 1981 price situation and an annual interest rate of 12%, heat- pump heating would require a C.O.P. of about 3 to be economically competi- tive. Inflation will tend to make hest Pumps more attractive by reducing the impact of the initial investment but we have not taken that into account. Also, if hydroelectric power is developed in interior Alaska, electricity prices can be expected to escalate at a slower rate than oil prices, which would be advantageous for the use of heat pumps. Besides the strictly economic consid- erations, there are several other factors which may play a significant role in the decision to use ground-coupled heat pump heating systems. Heat pumps can Operate automatically, are mechanically very reliable, require little maintenance, and present a negligible fire hazard. While these advantages provide benefits almost exclusively to the owner, the entire com- munity will benefit from the lack of atmospheric emission. OIL HEAT Furnace $1200 1000 galion tank 600 Excavation 250 Chimney 200 Hot air dist. system 1200 Installation & misc. 1000 TOTAL $4450 HEAT PUMP Heat Pump (Command-Aire SWP 541) $2000 1500’ pipe 1000 Ditch work 1800 Hot air dist. system 1200 Installation & misc. 1000 TOTAL $7000 RESISTANCE 60’ heaters $1100 Installation & wiring 500 TOTAL $1600 ” Before there can be any return on the additional investment required for a heat pump installation, the direct cost of the heat delivered by the heat pump must be lower than that of other systems. Using June 1981 Fairbanks prices,> the ratio of heat delivered by equal cost units of oil and electricity is 2.2. With a useful life of 15 years the yearly Payments on the installation costs for heat pump, oil, and electric heat at 8, 12, and 16% yearly interest are shown in Table 2. The amortization cost and the direct costs may be combined to give the total yearly cost of the different heating systems, which may be done 15.0 Oil Heat Most Economical 12.5 10.0 4 Heat Pump Most Economical C.0.P.=2.0 C.0.P.=2.5 oF oO ’ C.OP.=3.0 ’” Resistance Heat Most Economical 0 05 10 15 20 25 3.0 PRICE OF HEATING OIL ($/gal) PRICE OF ELECTRICITY (¢/kWh) i) N a a oO Figure 8. Total yearly costs for different heating systems in Fair- banks, assuming: an interest rate of 12%; annual heating load of 35,000 kWh; a furnace of 65% efficiency; and fuel containing 138,000 BTU/gal. Figure 17. Economic Analysis (reprinted from Stenbaek-Nielsen and Zarling, 1982). 42 Finally, we note that the ground-coupled heat-pump may be used as a component with other energy systems to produce an overall more economic heating system. As an example, a wind mill could be used to run the heat- pump. Most Sind mills used by individuals have a rated power of typically 5- 10 kw, which is not enough for space heating (the average power produced is only 30-50% of the rated power). However, if combined with a heat-pump the heat produced could be increased by a factor of 2.5-3.0, which would make home heating with wind energy feasible. 43 References Althouse, A.D., C.H. Turnquist, and A.F. Bracciano, Modern Refrigeration and Air Conditioning, Goodheart-Wilcox Company, Inc., South Holland, IL, 1968. Fairbanks North Star Borough, Community Research Center, The Energy Report, (11)2, August, 1981. Penrod, E.B., Earth Heat Pump Research; Bulletin No. 14, The Engineering Experiment Station, University of Kentucky, December, 1949. Stenbaek-Nielsen, H.C. and L.R. Sweet, Heating with ground heat: an energy saving method for home heating, The Northern Engineer, 7(1): 20-25, 1975. Stenbaek-Nielsen, H.C. and J. Zarling, Ground coupled heat-pumps: An Alaskan Experiment, The Northern Engineer, 14, 30, 1982. Thompson, W., On the economy of the heating or cooling of buildings by means of currents of air, Glasgow Royal Phil. Soc. Proc., 3:269, 1852. 44 APPENDIX I: Five year project plan. PROPOSED PROGRAM , Five-year plan A five-year plan is Proposed to devaion the use of ground-heat-pump systems in Alaska. This plan was earlier submitted through the University to the State of Alaska as part of the so-called "Seifert Report" and the project was one of those specifically mentioned by the legislature for funding through the Alaska Energy Center, The plan calls for three ground-heat-punp Systems to be installed in successive years and monitored for performance throughout the duration of the program, The first will be installed at the University's musk ox a home in the Fairbenks area. Both of these Systems will be operated electrically, The third systen is envisioned to be integrated with other alternate energy concepts; for example, it could be driven by wind energy and possibiy installed in a village. All systems will be closely monitored so that reliable guidelines for their design, installation, and use can be developed. Five-year plan: Years A. Develop ground-heat-pump systems suited for Alaskan conditions: 1. Electrically driven (suburban areas) 1-2 2. Non-electric (bush and rural communities) 2-3 B. Install system and monitor its operation (3 systems installed in successive years) 1. Site selection. Installation. 1-3 2. Monitor system (heat delivered, power used, thermal response of ground, effects of possible frost action in the ground, reliability of system, etc.) 1-5 c. System performance evaluation. | Models aimed to aid site evaluating, estimating operating costs and minimizing installation costs. Models to be refined as actual performance data accumulate. 1. Efficiency of heat exchangers and heat pump . 1-5 2. Response of the reservoir to the extraction of heat 1-5 os Optimizing ground collector size and design 1-5 D. Publication of results. Recommendations for use in various parts of Alaska. 1-5 Naturally, this plan will be reevaluated as the program progresses, and the activity for each year will be strongly dependent on the results accumulated. In the remaining part of this proposal we concentrate almost exclusively on the first installation, the data to be collected from this installation, and the analysis of this data. APPENDIX IL , OWNER’S MANUAL DUO 500 TABLE OF CONTENTS PAGE FOREWORD TO THE HOMEOWNER im INTRODUCTION al PRINCIPLE OF OPERATION THE HEAT PUMP - REFRIGERATION CIRCUIT THE ENERGY SOURCE AND COLLECTOR : HE HOT SIDE OF THE HEAT PUMP HOT WATER SYSTEM SPACE HEATING NETWORKS HYDRONIC NETWORK FORCED AIR NETWORK RoR WWI I Wp ph EG mm BDO RO DO FH — CONTROLS TEMPERATURE CONTROLS : SPACE TEMPERATURE CONTROL HOT WATER TANK CONTROL SYSTEM SAFETY GUARDS Fe be NON OWNOW WG DO FF es WI NO Fe NOM DD THE FRONT PANEL CONTROL PRO SELECTOR SWITCHES MODE SELECTOR SWITCH THE MONITORING LIGHTS GENERAL Hes pe pS ee ND fa pe po NO © CO CO NI < iy vu ADDENDUM HOT WATER TANK ASSEMBLY hu ho WN APPENDICES WIRING DIAGRAM LIST OF ILLUSTRATIONS FIGURE 1] - MECHANICAL SCHEMATIC Freure 2 - DUO 300 g [UO 500 FIGURE 3 - PRO SELECTCR SWITCHES FIGURE 4 - FRONT PANEL - CONTROL UNIT FOREWORD TO THE HOMEOWNER THIS PUBLICATION IS INTENDED TO BE OUR OPERATIONAL GUIDE FOR THE HOMEOWNER, AN ELEMENTARY EXPLANATION OF THE SYSTEM’S PRINCIPLE IS GIVEN, HOWEVER, A VERY PRECISE DESCRIPTION OF THE SYSTEM'S CONTROL ALLOWS THE HOMEOWNER TO SELECT THE ENVIRONMENTAL TEMPERATURE PROGRAM OF HIS/HER CHOICE. IN ADDITION, A SET OF APPENDICES DESCRIBE THE PERTINENT TECHNICAL FEATURES OF THE SYSTEM, I INTRODUCTION LR LON THE CANTHERM HEATING LTD DUO TERRATHERM/AQUATHERM SYSTEM TS DESIGNED TO PROVIDE THE HOUSEOWNER WITH TOTAL SPACE HEATING AND HOT WATER DEMANDS FOR THE HOME, (PROVIDED HOWEVER, THAT THE HEAT PUMP POWER OUTPUT IS SUEFICIENT FOR THE HOUSE), THE SYSTEM IS DIVIDED INTO TWO BASIC SUB-SYSTEMS: A) THE ENERGY COLLECTOR B) THE HEAT PUMP, SOLAR ENERGY, COLLECTED AND sTORED BY THE GROUND DURING THE SUMMER MONTHS IS USED AS THE ENERGY SOURCE, DURING THE HEATING SEASON, HEAT IS TRANSFERRED FROM THE GROUND TO THE HEAT PUMP BY MEANS OF A GROUND COLLECTOR, THE HIGH TEMPERATURES OUTPLTED BY THE HEAT’ PUMP PROVIDES SPACE HEATING AND DOMESTIC HOT WATER FOR THE HOUSE, PRINCIPLE OF OFERATION _ — 1 THE HEAT PUMP - REFRIGERATION CIRCUIT $A REE GCERATION CIRCUIT THE REFRIGERATION CIRCUIT OF THE HEAT PUMP CONSISTS OF A SET OF HEAT EXCHANGERS (ZVAPORATOR, DE-SUPERHEATER. CONDENSER AND SUB-COOLER), AN EXPANSION VALVE AND REFRIGERANT FLUID, THE REFRIGERANT FLUID USED I3 COMMERCIALLY KNOWN AS R 502 (or R 22), WITH REFERENCE TO FIG, 1, AT THE INPUT OF THE COMPRESSOR (pT 1), R 502 1s comPLETELY Gaseous AND AT LOW TEMPERATURE AND PRESSURE, : THE GAS IS COMPRESSED BY THE COMPRESSOR TO A HIGH PRESSURE (PT 2). WHEN A GAS IS COMPRESSED, ITS TEMPERATURE INCREASES AS WELL. THEREFORS, AFTER THE COMPRESSOR, THE GAS IS AT HIGH PRESSURE AND TEMPERATURE, EAT EXCHANGER (DE- STH S LOWERED (pT 3), TRE GAS LOSES HEAT THROUGH THE FIR SUPERHEATER) AND ITS TEMPERATURE | UPON PASSING THROUGH THE SECOND HEAT EXCHANGER ASSEMBLY (CONDENSER SUB-COOLER) THE REFRIGERANT GIVES UP SENSIBLE AND LATENT HEAT AND CONSEQUENTLY IT LIQUIFIEs (pT 4), MEANWHILE THE PRESSURE OF THE REFRIGERANT IS MAINTAINED HIGH BY THE EXPANSION VALVE, AS THE REFRIGERANT PASSES THROUGH THE EXPANSION VALVE THE LIQUID LOSES PRESSURE, WHEN A FLUID DECOMPRESSES ITS TEMPERATURE IS ALSO LOWERED, THEREFORE, DOWNSTREAM OF THE EXPANSION VALVE THE REFRIGERANT IS A MIXTURE OF LIQUID AND GAS AT LOW PRESSURE AND TEMPERATURE (PT 5), FROM HERE THE REFRIGERANT PASSES THROUGH THE EVAPORATOR HEAT EXCHANGER WHERE IT ABSORBS LATENT AND SENSIBLE HEAT, AT THE EXIT OF THE EVAPORATOR THE REFRIGERANT iS COMPLETELY GASEOUS (PT 1), THE FOREMENTIONED CYCLE THEN REPEATS, 2 THE ENERGY SOURCE AND COLLECTOR ENERGY TO THE HEAT PUMP IS PROVIDED BY THE SOIL OR SURFACE WATER, TO ACCOMPLISH THIS, A PIPE IS BURIED IN THE GROUND (oR RESTING AT THE BOTTOM OF A LAKE). BOTH ENDS OF THE PIPE ARE CONNECTED ACROSS THE EVAPORATOR OF THE HEAT PUMP, THE PIPE IS FILLED EITHER WITH A GLYCOL OR BRINE SOLUTION AND A PUMP IS USED TO CIRCULATE THIS LIQUID FROM ONE END OF THE EVAPORATOR THROUGH THE COMPLETE LENGTH OF THE PIPE AND BACK TO THE EVAPORATOR, THIS MEANS THAT THE ENERGY TO THE HEAT PUMP IS PROVIDED THROUGH A COLLECTOR WHICH IS A CLOSED LOOP IN CONFIGURATION, 3 THE HOT SIDE OF THE HEAT PUMP HEAT IS EXTRACTED FROM THE HEAT PUMP BY COOLING THE HIGH TEMPERATURE REFRIGERANT WITH WATER AT THE DE-SUPERHEATER AND CONDENSER SUB-COOLER HEAT EXCHANGERS, AS THE REFRIGERANT LOSES HEAT THE WATER GAINS IT AND BECOME HOT, THIS HOT WATER IS FED TO THE HOT WATER TANK CIRCUIT AND SPACE HEATING DISTRIBUTION NETWORK BY CIRCULATING PUMPS, 35 HOT WATER SYSTEM DURING COLD WEATHER OPERATION WHEN SPACE HEATING IS REQUIRED THROUGHOUT THE BUILDING, THE MEDIUM ABSORBS ENERGY FROM THE REFRIGERANT AT THE DE-SUPERHEATER, BY CONVECTION, THE HOT WATER CIRCULATES THROUGH THE CONDUITS AND THE CHAMBER WRAPPING THE HOT WATER STORAGE TANK, [F THE HOT WATER DEMAND IS HIGH AND ADDITIONAL HEAT ENERGY IS REQUIRED, THE SPACE HEATING CIRCULATING PUMP STOPS AND THE HOT WATER CIRCULATING PUMP IS STARTED, THIS ALLOWS HEAT TO BE ABSORBED BOTH FROM THE DE-SUPERHEATER AND CONDENSER SUB-COOLER HEAT EXCHANGERS, WHEN THE UPPER LIMIT TEMPERATURE OF THE HOT WATER IS REACHED, THE PROCESS IS REVERSED, 3,2 SPACE HEATING. NETWORKS SPACE HEATING IS NORMALLY DISTRIBUTED THROUGHOUT THE BUILDING VIA A HYDRONIC OR FORCED AIR NETWORK, 3,2,1 HYDRONIC NETWORK THE INPUT TO THE HYDRONIC DISTRIBUTION CIRCUIT IS CONNECTED DIRECTLY ACROSS THE CONDENSER SUB-COOLER HEAT EXCHANGER ASSEMBLY. THE RADIATOR CIRCULATING PUMP RUNS CONTINUEOQUSLY EVEN WHEN THE COMPRESSOR IS NOT, AS LONG AS THE CONTROL SWITCH IS ON ONE OF THE "On" POSITIONS (SEE FIGURE ), 35222 FORCED AIR NETWORK IN ORDER TO INTERFACE THE OUTPUT FROM THE HEAT PUMP TO THE FORCED AIR SYSTEM A WATER AIR COIL IS LOCATED IN THE MAIN PLENUM OF THE AIR DUCT NETWORK, THE INPUT TO THIS COIL IS CONNECTED ACROSS THE CONDENSER SUB-COOLER ASSEMBLY, AGAIN THE CIRCULATION PUMP WHICH DRIVES THE. WATER ALONG THE CIRCUIT RUNS CONTINEQUSLY AS LONG AS THE CONTROL SWITCH IS ON ONE OF THE “ON” POSITIONS (SEE FIGURE 4 ), NOTE HOWEVER THAT THE BLOWER WHICH MOTIVATES THE AIR THROUGHOUT THE AIR DUCT DISBRIBUTION SYSTEM, NORMALLY REQUIRES ADDITIONAL CONTROLS, LEGEND Sol (GQ WATER) SERPENTING EVAPORATOR LIRCULATING PUKID EXPANSION TANK VALVES COMPRESSOR SUPERHBATER CONSENSER/SUSTHOLER ALCUMULATQOA FILTEA/DRYER TPHRaDBWVAusens 12 SIGHT GLASS 43 EXPANSION VALVE ASSY LY TEMBERADURE SENSOA 15 PRESSURE TAD 45 HAT WATER TANK ASSY 17 CIRCULATING PUMA W CHEEK VALVE (9 INJECTOR 20 CIRCULATING PUMB eI CWALK VALVE 2 RADIATOR OF HEAT EXCHANGER IVHO3W IN YO i 3HOS N OILY) nN @ Cc Oo m 500 00 & Duo 3 AES ’ a\s ~ \ y ) aang bee LEGEND - FIGURE 2 ja > Wi bdo + FRAME COMPRESSOR BRINE PUMP DE-SUPERHEATER EVAPORATOR CONDENSER /SUB-COOLER EXPANSION VALVE ASSEMBLY RECEIVER SIGHT GLASS FILTER/DRYER CIRCULATING PUM? HOT WATER CIRCULATING PUMP SPACE HEATING Ii] CONTROLS be TEMPERATURE CONTROLS Til SPACE TEMPERATURE CONTROL THE CONTROL UNIT MATCHES THE SIGNAL FROM AN OUTDOOR TEMPERATURE SENSOR TO THAT OF ANOTHER SENSOR, MONITORING THE RETURN WATER LINE TEMPERATURE, THE CONTROL WILL THEN OUTPUT A COMMAND WHICH DETERMINES THE STOP START MODE OF THE SYSTEM AND THUS THE COMFORT TEMPERATURE INSIDE THE HOUSE, 1,2 HOT WATER TANK CONTROL IN ADDITION TO THE SPACE TEMPERATURE CONTROL THE SYSTEM ALSO INCORPORATES A LOGIC MODULE, WHEN THE TEMPERATURE OF THE HOT WATER IN THE TANK FALLS BELOW APPROX 45°C (113°F) THE CONTROL STOPS THE RADIATOR PUMP AND STARTS THE HOT WATER TANK PUMP (AND OF COURSE IT WILL START THE COMPRESSOR IF IT HAPPENS TO BE OFF), WHEN THE TEMPERATURE OF THE WATER IN THE TANK READS APPROX 58°C (136°F) THEN THE CONTROLS STOP THE HOT WATER TANK PUMP AND START THE RADIATOR PUMP, dS: SYSTEMS SAFETY GUARDS ai? SYSTEMS SAFETY GUARDS IF THE COMPRESSOR SUCTION PRESSURE FALLS BELOW THE DESIGN LIMIT. THEN LIQUID MAY ENTER THE COMPRESSOR CAUSING DAMAGE TO IT, SIMILARLY IF THE DISCHARGE PRESSURE BECOMES TOO HIGH, THAT IS ABOVE THE DESIGN LIMIT, THEN THE ASSOCIATED TEMPERATURES WILL CAUSE SYSTEM FAILURES, TO PROTECT THE SYSTEM AGAINST THESE POSSIBILITIES, LOW AND HIGH PRESSURE PRESSOSTATS WILL PREVENT THESE LIMITS.-TO BE EXCEEDED, IF ONE OF THE PRESSOSTATS TRIPS, THEN FOR ADDED PROTECTION, 17 CAN ONLY BE RESET MANUALLY, A COMPRESSOR CRANK CASE OIL HEATER IS ALSO PART OF THE SYSTEM'S SAFETY GUARDS, AS LONG AS ELECTRICAL POWER IS AVAILABLE TO THE UNIT, THE OIL HEATER WILL’ BE ON WHEN THE COMPRESSOR IS NOT RUNNING, THE WARM OIL KEEPS THE REFRIGERANT IN A GASEOUS STATE, WHICH FACILITATE COMPRESSOR START-UPS, Co IV THE FRONT PANEL THE TEXT THAT FOLLOWS WILL INSTRUCT THE HOMEOWNER HOW TO SELECT A TEMPERATURE ENVIRONMENT BEST SUITED FOR THE HOME, THE DESIRED PROGRAM IS SELECTED BY POSITIONING BOTH THE CONTROL SELECTOR SWITCHES AND THE MODE SELECTOR SWITCH (SEE FiIGguRE 4), 1 CONTROL - PRO SELECTOR SWITCHES (SEE FIGURE 3) © Ro Ho Cc 0 SYSTEM IS OFF DAY SETTINGS AS PER SLIDER “B" AND NIGHT OFF AS PER TIME SWITCH DAY AND NIGHT SETTINGS AS PER SLIDERS “B* AND "C" AND TIMER SWITCH SETTING FOR BOTH DAY AND NIGHT AS PER SLIDER “c" SETTING FOR BOTH DAY AND NIGHT AS PER SLIDER “B* MANUAL SETTING - HEAT PUMP WILL OPERATE AND ALL CONTROL FUNCTIONS ARE BY PASSED, THE SYSTEM WILL SWITCH OFF WHEN ONE OF THE LIMITING PARAMETERS IS EXCEEDED, FIGURE 35 CONTROL - PRO SELECTOR SWITCHES u > — PROGRAM SELECTOR SWITCH ~ DAY TEMPERATURE SETTING SLIDER ~ NIGHT TEMPERATURE SETTING SLIDER - TIME DIAL AND RIDERS A B c D - HEATING CURVE SELECTOR SWITCH E F - TIME INDICATOR G - INSTRUCTION SHEET (CONTROL ONLY) TEMPERATURE SETTING SLIDER _ 25°C (77°F) max 20°C : (62°F) I~, ”«CO«#&B®SCRED)«-DAY TEMPERATURE SETTING 14°C ~—- 2°C (37°F) (579F)] C (BLUE) NIGHT TEMPERATURE SETTING 69°C (43°F) mary HEATING CURVE SLIDER IT SELECTS THE CURVE WHICH THE CONTROL WILL FOLLOW AS THE OUTDOOR TEMPERATURE CHANGES, FOR BEST HEAT PUMP OPERATION THE "0,5" and "0.75" cuRVEes ARE USED, Your instailation engineer determined > the basic vaiue for your installation and Set the slider o accordingly. Date | Value 3 8 Ra en ee | Flow temperature Outdoor temperature THE POSITION OF THIS SLIDER IS INITIALLY SET BY THE INSTALLATION PERSONNEL, FIVE ADJUSTMENTS OF THE SLIDER CAN BE MADE BY THE HOME OWNER DURING THE FIRST WINTER OF OPERATION, FIGURE 4 TEMPERATURE CONTROLS PILOT LIGHTS DIAL & SLIDERS MULTIMODE SWITCH ELECTRICAL OVERLOAD FUSES CLOCK FRONT PANEL - CONTROL UNIT TIME SWITCH DIAL THE TIME SWITCH DIAL WILL ALLOW THE HOMEOWNER TO SELECT A PROGRAM TO SWITCH THE HEAT PUMP “ON” oR “OFF” AND FROM A "NIGHT" TO "DAY" TEMPERATURE AND VISE-VERSA WHENEVER HE/ SHE CHOOSES, Led MODE SELECTOR SWITCH (SEE FIGURE 4) THIS SWITCH COMPLIMENTS THE CONTROL PROGRAM AS FOLLOWS: POSITION: OF I THE HEAT PUMP WILL NOT COME ON EVEN THOUGH THE DEMAND MAY EXIST, HOWEVER, THE RADIATOR CIRCULATING PUMP WILL BE RUNNING, 1 THIS IS A NORMAL RUNNING MODE PROVIDED THAT THE CONTROL SWITCH IS ON ONE OF THE "ON" POSITIONS, THE HOT WATER DEMAND TAKES PRIORITY OVER SPACE HEATING WHEN BOTH DEMANDS EXIST, 2 THIS IS AN “ON® POSITION WHEN THE CONTROL SWITCH IS ON ONE OF THE "on™ POSITIONS, IN THIS POSITION BOTH THE RADIATOR AND HOT WATER PUMP WILL RUN, HOWEVER, THE HOT WATER DEMAND TAKES PRIORITY OVER SPACE HEATING WHEN BOTH DEMANDS EXIST, - ll - 5 THIS POSITION IS PRESENTLY NOT UTILIZED. IT IS PRESENTLY USED AS AN OFF POSITION, HOWEVER. WHEN SELECTED, BOTH THE RADIATOR AND HOT WATER PUMPS WILL RUN EVEN THOUGH THE’ SYSTEM IS NOT ON, 1s2 THE MONITORING LIGHTS (SEE FIGURE 4). A Sei OF PILOT LIGHTS ARE LOCATED ON THE FRONT PANEL ALLOWING THE HOMEOWNER TO QUICKLY DIAGNGSE THE STATE OF THE HEAT PUMP SYSTEM, PILOT LIGHT NO: 1 THIS LIGHT MERELY INDICATES THAT ELECTRICAL POWER IS AVAILABLE FROM THE MAIN (GREEN), 2 THIS LIGHT COMES ON WHEN THE BRINE PUMP IS RUNNING (ORANGE), 3 THIS LIGHT COMES ON WHEN THE COMPRESSOR IS RUNNING (ORANGE) 4 THIS LIGHT COMES ON WHEN THE RADIATOR PUMP IS RUNNING (ORANGE) 5 THIS LIGHT COMES ON WHEN THE HOT WATER PUMP IS RUNNING (ORANGE) 6 NOT CONNECTED (ORANGE) 7 NOT CONNECTED (RED) oo NOT CONNECTED (RED) 9 THIS LIGHT COMES ON WHENEVER THE LOW PRESSURE PRESSOSTAT TRIPS ON LOW PRESSURE (RED) 10 THIS LIGHT COMES ON WHENEVER THE HIGH PRESSURE PRESSOSTAT TRIPS ON HIGH PRESSURE (RED) ll NOT CONNECTED (RED), 1,3 GENERAL AN HOUR COUNTER MOUNTED ON THE FRONT PANEL WILL ALLOW THE HOMEOWNER TO DETERMINE THE TOTAL RUNNING TIME OF THE SYSTEM, ELECTRICAL OVERLOAD FUSES ARE LOCATED ON THE FRONT PANEL TO FACILITATE THEIR ACCESSABILITY, - 13 - Vv ADDENDUM 1 HOT WATER TANK ASSEMBLY THE HOT WATER TANK ASSOCIATED WITH THE DUO HEAT PUMPS IS SPECIALLY DESIGNED TO OPTIMIZE HEAT EXTRACTION FROM THE HEAT PUMP WHILE PROVIDING THE REQUIRED SPACE HEATING, TO NOTE THAT SOME TANKS MANUFACTURED BY OTHER TANK MANUFACTURING COMPANIES COULD BE ADOPTED TO THE HEAT PUMP, HOWEVER, A MODIFICATION TO THE HOT WATER TANK CIRCUIT MAY BE REQUIRED, >| 9 cm (3.3 i >|<— <——__—_________ 138.8 cm (54.6 in) os APPENDIX I PHYSICAL DESCRIPTION - DUO 500 HEAT PUMP Ga eee er sce een ee ee ee ioe a Drei ec DIMENSION AND WEIGHT DUO 500 _ 60 x 60 x 162 cm (24 x 24 x 64 IN) 322 xg (711 LBs) HOT WATER 60 x 60 x 180 cm aa (24 x 24 x 71 IN) 155 ke (342 LBs) CAPACITY 270 LIT (60 GaALLons) |<—-457.7 cz (22.7 in) __y| [<— 97-7 cw (22.7 in) —yy \< 59.8 ca (23.5 in) >| O Oo FROM COIL/ Je— 59-3 em (23.5 ia) __yy fee esece e t zetes pO) fe eh >| | ————>} 65.3 cm (25.7 in) —" m (44.2 in) FROM GROUND COLLECTOR O l« |<————112..4 138.8 cm (54.6 in) TO GROUND COLLECTOR QUO HEAT PUMP HaS AQJUSTASLE 3ASE FRONT PANEL SIDE PANEL LEFT TO coy RADIATOR RADIATOR TO HOT WATER TAN: me TOP PANEL |<— >} 20.2 ca (7,9 ia) in) FROM HOT WATER TANK SIDE PANEL RIGHT f 20.2 ca (7.9 ia as 123.8 cm (48.7 in) APPENDIX II DUO 300 & DUO 500 perForMaNce CURVE CAPACITY DIAGRAM DUO 300 HEAT OUTPUT IN KW 15 38°C cont 43°C 10 ae 52°C re eui ie 5 INPUT POWER 52°C TOTAL asc = > ————=—35¢ -5 0 +5 +10° °C BRINE INLET A) BRINE FLoW = 10 us GAL/MIN B) SPACE HEATING WATER FLOW & CAPACITY DIAGRAM DUO 500 15 HEAT OUTPUT IN KW 10 -————__- (37. LIT/MiNn) 4,5 us GAL/MIN (17 LIT/MIN) TYPICAL APPENDIX III HANDLING BE SURE TO TRANSPORT THE DUO HEAT PUMP IN AN UPRIGHT POSITION, THE PUMP MAY BE TILTED SIDEWAYS, AS LONG AS THE BRINE PUMP CONNECTIONS ARE TURNED UPWARDS, SOUND LEVEL THE SOUND LEVEL FOR THE DUO 300 aND Duo 500 Is APPROXIMATELY 50-40 DBA, To FURTHER REDUCE NOISE LEAKS, WE RECOMMEND THE USE OF A SOUND DAMPER WHEN CONNECTING THE HEAT PUMP TO THE RADIATOR LINE, TECHNICAL DATA REFRIGERANT R 502 (or R 22) BRINE PUMP GRUNDFOS CP3-10U 230 V 60 Hz SINGLE PHASE OPERATING AMPS 3,7 A POWER 345 W WATER PUMPS GRUNDFOS UP 26-64 230 V 60 Hz SINGLE PHASE OPERATING Amps 0;80 A PoweR 185 W COMPRESSOR - DUO 300 COPELAND CRH1-0275-PFY 230 V 60 Hz SINGLE PHASE OPERATING AMPS 12,5 A PoweR 2600 W DUO 500 COPELAND CRM1-0400-PFY 230 V 60 Hz SINGLE PHASE OPERATING AMPS 19,0 A PoweR 4000 W TOTAL OPERATING AMPS DUO 300 - 17,8 A DUO 500 - 24,3 A 7 16 is ‘ 3 2 [— | Lz CAS POUVLIR A UN COTE QUT est mIS-a- ta ou VERNIER UEYRA SZ RACCORVER AU TERMINAL by L c ONE SIUE OF CHE FLZCTRICAL SUPPLY [5 CRCUNLED Ja NEYTRAL PINAL, 5S THE GES.NATED VERMINAL 70 BE CONNECTED 70 GROUND “SUPPLY ta tz fet SS K —— x N 4 ’ + ” I i ' } | \ ’ é ' Fr { SOMPRESSSR wiming oaGRam ' searce + 1! , '— §— SL 5 ce eecssoF zaatse SYMBOLS ANO_LECEN ny euve . MOT waTEeR pune PILCT LIGHT ‘ » cMERUAL - PRESSURE 2 Cn 4 e (a) COMPRESSUK &S Pu RADIATOR (Ma) PUMP. HOT wac3R vv THESMOSTAT , HIGH CDMPERACURS — se acne 2 GLASTON UNIT = e 2) RBGILASY t ~ Le on CG) vewperaruaz savsoa, anvtator CS ® TEMPERATURE SENSOR, QUTSIUE TEMPERATURE ® THERMOSTAE =, KOT WATER HERM HEATING LINITED chains propristary in tne Inte- @© PRESSOS/AT KOT «ATER thon disclosed hereon. ‘Ris drawing {ts furmianee in configence 3 Cy CRANKCASE HEATER She express understanding tha: neitner it ner any repreductio ec CONTROL, HIGH AND LOW PRESS eof will ve disclo O others or weed for the purpe. ® Po BOAaD aanufacture of procurement oF the article ar part «nom vere 1) CLOCK Marea a CT T 1 T Tera Tweet { L tt | I —_ + = T T cot T i r aeacnal 7 APPENDIX LIL INSTALLATION SERVICE MAINTENANCE MANUAL for SWP/H WATER /AIR HEAT PUMP “e/ _XECOMMAND/AIRE CORPORATION » 3221 SPEIGHT STREET e PO. BOX 79166 WACO. TEXAS 76710 # TELEPHONE 817/753-3601 UNPACKING & INSTALLATION @ The Command-Aire Heat Pump is a self-contained, factory assembled 3 unit. Each unit has been inspected and operationally run tested at the factory by Quality Control. The unit has heen packaaed to arrive in good condition, however mishandling in transit can cause damage. Report evidence of visible and concealed damage to the carrier's agent immediately. Request an inspection and a report to originate a claim. PRINCIPLE OF OPERATION OF THE HEAT PUMP The basic principle of operation of the water to air heat pump is that heat is extracted from the air and rejected to the water on the cooling cycle. Dehumidification is also achieved on the H cooling cycle by removal of moisture from the air in the form of condensate. In the heating cycle the refrigerant flow is reversed and heat is extracted from the water and used to warm the room air. - Basic components used in the system are the compressor, tube in shell heat exchanger, a finned coil heat exchanger, a reversina valve, and a circulating blower. The reversing valve Operates the system in either the cooling or heating mode. (See Fig. 1 & 2) A manual selector switch or an automatic chanaeover switch on the thermostat determines whether the unit will operate on coolina or heating cycle. The unit will be controlled automatically by the thermostat. The Command-Aire Heat Pump is a factory assembled unit, requiring electrical power of the proper voltage, an adequate supply of water in the range of 60° to 95°F. A drain for wasting the condensate water is required. Duct work to supply air to be conditioned and return conditioned air is also required. INSTALLATION OF UNIT Typical installation of the SWP "vertical" models is illustrated in the following diagram: Fig. 3 - Unit in a Closet Installation. Typical installation of the SWPH "horizontal" models is illustrated in the following diagram: Fig. 4 - Ceilina mounted installation. For acceptable operation of the heat pump; particular care in location, setting, and connection of. the heat pump must be exercised. The following points should be considered when installing a Command Aire Heat Pump. A) All units should be installed to provide space for removal of access panels for servicing the compressor and air handler sections. B) Prevention of noise and vibration transmission to the occupied spaces, building structure, ducts and pipina. It is recommended that vibration eliminator pads be installed under the base of vertical units. The compressor is internally spruna and bolted to the base with special isolation mounts. After installation of the unit, the hold down nuts should be loosened so that the compressor is floatina free, Install flexible duct connections between the unit and the duct C) The ducts should be designed for velocities in accordance with ASHRAE standards. It is recommended that airborne noise be controlled with sound attenuating materials. The PIPING Recommended water piping to the unit is shown in Figs. 5 & 6. Connect water and condensate by means of flexible hose connections. Hoses used to make water connection to the unit must be suitable for the system water pressure. The condensate line in SWP/H should be trapped, as required hy local codes, at the unit and should be pitched away from the unit. unit and provide a means of water shut-off should it be necessary when servicing the unit. Indicating flow meters in the supply line to each unit are very desirable. Successful operation of the heat pump depends on the correct quantity of water to the unit. Undersized pipes and low Pressure will result in low water: flow causing high head pressure in Summer operation and possible freezing of the water in the heat exchanger during the winter operation. Excessive water flows will overload the unit in the heating cycle and reduce capacity in the cooling cycle. Water flow rates for efficient Operation are listed in the product specification sheets. The water temperatures to the unit must be between 60°F minimum and 100°F maximum. The unit will not operate efficiently at water temperatures outside of this range and may result in damage to the unit. The water must be clean, free of sand and solid foreign matter and’ entrained air. Air in the system will reduce the capacity of the heat exchanger, cause oxidation and scale, and create noise in the piping. Galvanized pipe or fittings are not recommended for use with these units due to possible electrolysis action. When using a semi-closed system, with an "open" cooling tower » the water treatment system should be operational with initial water flow and must condition the water to prevent corrosion and/or scale for trouble free operation. NOTE: Operation of C/A units on Poor quality water or ' incorrect flow is detrimental to the C/A units and voids the warranty. WIRING Power wiring to the heat pump should be in conformance with applicable codes and connected as shown on the wiring diagram furnished with the unit. No starters are required, Each Heat Pump is furnished for a rated voltage frequency and phase marked on the data plate. For units with a nameplate marking of 208/230 volts, the permissible operating voltage range is 197-253 volts. For units with other voltage markings the operating range must be within plus or minus 10%. The nameplate data indicates the fuse size or circuit size for each ‘compressor circuit. Make certain that the unit is adequately grounded, ‘For 208 volt operation make the necessary change in transformer wiring as shown on the wiring diagram furnished with the unit. Low voltage wiring between the terminal board in the unit control Panel and the wall thermostat should be made in conformance with applicable codes. Color coded low voltage cable is recommended to simplify wiring between the thermostat and unit. CARE OF IDLE UNITS Idle units may have numerous problems on startup mainly for the reason of not being used. Freon migrates to the condenser taking entrained oil with it thereby rendering the compressor relatively dry of lubrication; check valves will malfunction for lack of oil, etc. These things could relate to problems such as lack of heating or cooling and may cause failures of out of warranty parts upon start-up, Units that are installed in unoccupied spaces should be in a minimal operation mode. The following is recommended: A) During Summer (Cooling Season) - Thermostat set at 85°F, system switch on COOL, fan switch on AUTC. B) During winter (Heating Season) - Thermostat set at 60°F, system switch on HEAT, fan switch on AUTO. energy. CHECK, START-UP AND TEST After the unit has been installed, wired, piped and ducted, the unit is ready to be checked, tested and balanced for continuous Operation. Before starting the unit check the following: Proper voltage to unit Correct fuse sizes Tight electrical connections Water system clean and flushed Air Purged from water system OPWN— Serer Sw ‘ Set water flow for the proper quantity Water temperatures between 60°F and 1000F Condensate line clear and unclogged Blower wheel free to rotate © Return air filter is installed Access panels and enclosures in place Thermostat on OFF position aoe N-OWOND ewe ms SSS To start and balance the unit follow these steps: Adjust the room thermostat to its lowest settina and turn the thermostat switch to COOL position. Set the fan switch on AUTO. The unit should operate. If the unit has failed to start see the trouble shootina guide section. The difference between the entering and leaving water temperatures can be felt. Determine that the leaving water temperature is between 85°%and 105°F (depending on the incoming water temperatures and unit design conditions as specified in the Engineering Data Sheets.) Normally about 10° - 129 hotter than supply water. Check for cool air at the outlets after a few minutes of operation. Air flow in each area should be adjusted to the design airflow. The air temperature should drop approximately 15° to 25°F de- pending on the airflow thru the unit and the wet bulb temperature, If the air is too cold (more than. 22°F drop from entering air) or too warm (less than 16° drop from entering air) check the air flow. ‘ 4 Turn the thermostat selector switch to OFF position, a "“hissina" sound should be noticeable at the unit indicating a properly functioning reversing valve. Let the system pressure equalize for about two minutes. Adjust the thermostat to its highest setting and the thermostat selector switch to HEAT. The difference between the entering and leaving water temperatures can be felt. Determine that the leaving.water temperature is between 50°F and 75°F (depending on the incoming water temperatures and unit design conditions as specified in the Engineering Data Sheets.) Normally about 79 - 10° cooler than the supply water, Check for hot air at the outlets after a few minutes of operation. Air flow in each area should be adjusted to the design airflow. The air temperature should rise approximately 20°F to 40°F depending on the airflow thru the unit and the wet bulh temperature. If the air is too hot (more than a 40°F rise from enterina air) or too cool (less than a 20°F rise from entering air) check the air flow. Check for any vibrations, unusual noises or water leaks. After being satisfied that the unit operates normally and the system is ready to run, the thermostet selector switch should @ be set on either HEAT or COOL dependina on the climatic conditions and temperature setting at the desired level of comfort. 8 OPERATING INSTRUCTIONS Operation of your Command-Aire Heat Pump is designed for ambient air temperatures of not less than 40°F, The standard model is designed for indoor installation and when installed in an unconditioned space, the unit May not start in cool weather, (approximately 50°F). In this case, it may be necessary to start the unit on cooling in cool weather for three to five minutes, then shut off and turn to heat after one minute shut down. Also, check the freeze protection thermostat because it may be affected by ambient temperature. The Command-Aire unit is equipped with safety controls which include a high pressure control, freeze protection thermostat, and a motor overload switch in larger models, set to shut off the compressor under abnormal operating temperatures and pressure conditions. Other optional safety controls are available such as low pressure switch. If any of these controls shut off the compressor, a lockout relay prevents short cycling from the abnormal condition. When conditions have been corrected the control lockout can be reset by setting the thermostat selector switch to OFF, waiting a few minutes for the system pressures to equalize, and then returning to HEAT or COOL. If the condition continues an authorized serviceman should check out the unit. For economical operation of the Command-Aire Heat Pump it is advisable to prevent heat transmission from the outdoor or other non air conditioned spaces, to the conditioned space. _A popular but erroneous concept is that if the thermostat is set at extremely low or high temperatures the unit will cool or heat faster. It is good practice to set the thermostat at the desired level of comfort and leave it there without trying to achieve comfort levels by constantly manually changing the thermostat. Like any other type of mechanical equipment, the Command-Aire Unit performs best when it is well maintained. There is no substitute for the "know how" and experience of a competent refrigeration and air conditioning serviceman. THERMOSTAT HEAT ANTICIPATOR SETTING Set the heat anticipator scale to match the primary control rating. When using a thermostat with 2 stages of heating, set both heat anticipators to match their respective primary control rating. The current draw of each heating stage must be measured with the thermostat removed for best results. 1) Connect an ac ammeter of appropriate range between the heat- ing terminals of the subbase - Stage 1 - between R and W1 Stage 2 - between R and W2 2) Move the system switch to HEAT or AUTO. 3) After 1 minute, read the ammeter and record the reading for each stage. 4) After mounting the thermostat, set the adjustable heat anticipator to match the respective reading measured in step 3 NOTE: Wiring to thermostat must be run in 18 quage or heavier wire to keep the’ resistance of the thermostat circuit to less than 13s ohms. PREVENTIVE MAINTENANCE INSTRUCTIONS Regular service greatly improves the operating efficiency, re- 6 liability and longevity of Command-Aire Units. Maintenance on the unit is simplified to the following items. 1) The Command-Aire Heat Pump is furnished with a one inch fiberglass throwaway type air filter. This unit should not be operated without this filter in place. Filters should be inspected every three months and replaced when it is evident they are dirty. Unit operation becomes very inefficient with dirty filters. Three or four filter replacements may be necessary a year. 2) Condensate drains can pickup lint and dirt, especially with dirty filters. Inspect the condensate pan and drain twice a year to avoid the Possibility of overflow. 3) For units that are on city water or well water, it is im- portant to check the cleanliness of the condenser. Should the condenser become contaminated with dirt and scaling, as a result of bad water, the condensers will have to be back flushed and cleaned with a chemical that will remove the scale. This service should only be performed hy an experienced serviceman. @ Cooling Towers must be maintained, kept free of alaae and con- taminates and should have water treatment. 4) Check the contactors and relays within the control panel at Teast once a year. It is aqood practice to check the tightness of the various wiring connections-within the control panel, (especially when line power wiring to the machine is aluminum, ) 5) The blower motors are rated permanently lubricated. The belt driven blowers require oiling twice a year with a few drops of #20 SAE non-detergent oil. This should be done by a competent refrigeration service mechanic and not over oiled. It is good practice to inspect for belt wear and tension at this time. Correct belt tension is for the motor to be resting by its weight on the belt. If the belt is excessively tight there will be excessive heat qenerated in the bearinas and ultimate failure. On a closed circuit water system there are auxiliary equipment such as boilers, towers, and pumps which also require preventive maintenance just as much as the units for a trouble-free system. @ cs) 8 60° ae? 70° 80° COOLING CYCLE: Range of Approximate Operating Pressures (PSIG)* LEAVING WATER TEMPERATURE (F°) [ast (°F) SUCTION DISCHARGE SUCTION DISCHARGE SUCTION DISCHARGE 70-76 240-260 190-210 | 68-74 195-215 200-220 72-78 245-265 76-80 250-270 * Variances from these operating pressures will occur @rom machine to machine, model to model. HEATING CYCLE: Range of Approximate Operating Pressures (PSIG)* WATER TEMPERATURES REFRIGERANT PRESSURE (PSIG)* AIR ON OF -OF ENTERING OF LEAVING SUCTION DISCHARGE 60° 530 55-70 230-260 70° 70° | 63° 60-75 250-280 go° 73° 65-80 270-310 240-270 53° 63° 260-290 73° * Variances from these operating pressures will occur from machine to machine and model to model. : ada COMPLAINT @ P ENTIRE UNIT DOES NOT RUN » ) UNIT OFF ON HIGH PRESSURE CUT-OUT } CONTROL UNIT OFF e ON LOW TEMPERATURE CONTROL POSSIBLE CAUSE Thermostat Broken or loose wires Blown Fuse Control Center Voltage Supply Low High Pressure Switch Discharge Pressure. Too High Refrigerant Charge Freezestat CHECKS AND CORRECTIONS Set thermostat selector switch on "Cool" and lowest temperature setting, unit should run. Set thermostat on "Heat" and highest temperature setting, unit should run. Set fan on "Run", fan should run. If unit does not run all three “cases the thermostat could be wired incorrectly, or faulty. Replace or tighten the wires. Replace fuse or reset circuit breaker. Check 24 volt transformer for burnout or voltage less than 18 volts. If voltage is below minimum vol- tage specified on dataplate, con- tact local power company. Check for defective or improperly calibrated high pressure switch. On COOLING Cycle: Lack of adeouate water flow. Entering water too warm. Scaled or pluaged condenser. On HEATING Cycle: Lack of adequate air flow. Check blower, cloqaged filter, coil. or restrictions in duct work. Entering air too hot. Entering water temperature to high. Excessive water flow. The unit is overcharged with re- frigerant. Bleed off some charae Or evacuate and recharge with specified amount of R-22. Check for low water temperature, low water flow, and low ambient. Increase water flow for lower temperature. COMPLAINT BLOWER OPERATES BUT COMPRESSOR DOES NOT POSSIBLE CAUSE Thermostat Wiring High Pressure Control and Freezestat Control Compressor Overload Open Inoperative ‘Compressor Defective Capacitor Compressor Motor - Grounded Compressor Windings Open Voltage Supply Low CHECKS AND CORRECTIONS Check settina, calibration and ¢ Wiring. ‘ Check for loose or broken wires at compressor, Capacitor or contactor. The unit could be off on the hich Pressure or freezestat cut out control. Reset the thermostat selector switch to "OFF", After a few minutes turn to "Cool". If the compressor runs, unit was off on safety control (see complaints for possible causes.) If the unit still fails to run, check safety controls for mal- function by jumperina the various safety control to determine cause. If the compressor dome is too hot to touch the overload will not reset until the compressor cools down, If the compressor is cool and the overload does not reset, there may be a defective or open overload. If the overload is external replace the overload, otherwise replace the@ compressor. Try an auxiliary capacitor in parallel with the run capacitor momentarily. If the compressor starts but the problem reoccurs on startina install an auxiliary start kit. The hard start kit com- prises of a recommended start re- lay and correctly sized capacitor. If the compressor still does -not start, replace the compressor. Check capacitor, if defective remove & replace. Internal windina qrounded to the compressor shell. Replace the compressor. Check continuity of the compressor windings with an ohmmeter. If the windings are open, replace the compressor, If the voltage is below minimum vol- tage specified on the dataplate, contact local power company. COMPLAINT 8 NOISY OPERATION POSSIBLE CAUSE Compressor Blower and Blower Motor Contactors "Rattles and Vibrations Air Noises Water Noises ‘to correct quantity. CHECKS AND CORRECTIONS The hold down bolts used for shipping should be lossened so that the compressor is floating free on its isolator mounts. Make sure the compressor is not in direct contact with the base or sides of the cabinet. Excessive noise will ‘occur if the compressor has a broken valve or loose discharge tube. Replace the compressor. Blower wheel rubbing the blower casing. Adjust for Clearance and alignment. Bent blower, check and replace if damaged. Loose blower. wheel on shaft. Check and tighten. Defective bearings. Check and replace, A "chattering" noise in the contactor could be due to control voltage less than 18 volts. Check for low supply voltage, low transformer output or extra Jona runs of thermo- Stat wires. If the contacts or coil is defective repair or replace. Check for loose screws, panels or internal components. Tighten and secure. Copper Piping could be hitting the metal surfaces. Care- fully readjust by bending slightly. Undersized ductwork will cause high airflow velocities and noisy opera-- tion. Sand or gravel in water. Air in water will cause a noise which sounds like aravel or sand in water. Excessive water through the water- cooled heat exchanger will cause a noise. Throttle the water flow COMPLAINT INSUFFICIENT COOLING OR HEATING UNIT SHORT CYCLES POSSIBLE CAUSE Thermostat Compressor Reversing Valve Airflow Loss of Conditioned Air by Leaks Incorrect Water Flow Operating Pressure Refrigerant - System Unit Oversized Thermostat Wiring and Controls Compressor Overload CHECKS AND CORRECTIONS Improperly located thermostat (ecg near kitchen sensing inaccurately the comfort level in living area.) . Check for defective compressor, If discharge pressure is too low and suction pressure too high, compressor may not be pumping prop- erly, if so replace compressor. Reversing valve creatina by-pass of refrigerant from dis- charge to suction side of compressor Lack of adequate airflow or improper distribution of air. Check for leaks in ductwork or introduction of ambient air through doors and windows. Check water flow rate & reset if necessary. Incorrect Operating pressure. (See chart) Check strainer and capillary tubes @ for possible restrictions to flow of refrigerant. The refrigerant system may be contaminated with moisture, non-condensibles and Particles. Dehydrate, evacuate and recharge the system. Recalculate heat qains or losses for space to be conditioned. If excessive rectify by adding in- sulation, shading, etc. Check thermostat heater setting. The thermostat differential may be. set too narrow. Loose connections in the wiring or the control contactors defective. Defective compressor overload, check and replace if necessary. If the compressor runs too hot it may be due to an incorrect refriaq- eration charge. SW-SWP Installation Detail { Do Not Attach Ceiling | | Wires To or Through Duct! rt f Ceiling Optional Return i fi Air Grille - Line Supply Duct With Minimum 3° Insulation For Noise Control Flexibie Duct Connector + SW- SWP. Vertical | Unit Return Air ———————> Door Grille & Sound Boot Solid Vibration Isolation Pad Install Total Area of Base , | < >" i Recommended Clearance If return air duct is not used, applicable installation codes may limit this cabinet to installation only in a single story building. CA-O078-NERS REFRIGERANT FLOW DIAGRAM Reversing Vaive: (ENERGIZED) ‘Condenser ad Strainer | Compressor Check Vaive Conditioned Air {coouns) Reversing Valve (DE-ENERGIZED) WATER in) —= (DECREASE AT APPROX. 6°) WATER OUT € Compressor Conditioned Air (HEATING) C&-069-HERS Blower Motor Access Panel (both sides) Vent condensate with P-trap. Connection must slope away from unit. See below. SWH - SWPH Installation Detail Electrical Access Panel (this side) Hanger Bracket (see seperate detail) Return Air Filter Flexible Hose Condensate CA- O079-nERe a Flexible Dyct Connector — a } wl Do Not Attach Ceiling 1) comes { So “| Wires To or, Through Duct ny SWH-SWPH | Horizontal Noise Isolation Boot & Filter et \ ! \ , =Ceiling ¥ Line Supply Ouct, \t upply Air With Minimum 3 Return Air Insulation For ; Grille Noise Control Grille INSTALLATION RECOMMENDATIONS FOR SUPPLY / RETURN AIR NOISE ISOLATION (1) OPEN RETURN : Use isolation boot shown above made from duct board or sheet metal duct with 3° of liner adjoining unit. (2) DUCTED SUPPLY/ RETURN : Use 90° turn shown below made 1 . from duct board or sheet metal duct with 3° liner adjoining unit. (3) Use flexible duct connectors and turning vanes on sheet metol duct work. Select proper duct size and instoll per Ashrae guide. Line Supply Duct, With Minimum 3 Insulation For | Noise Control SRLS SSS SWH- SWPH << Supply Air Duct Horizontal Unit . Flexible cue Connector CA-O80- HERS GROUND TYPICA WIRIN FOR SINGLE BLOWER COMPRESSOR COMPRESSOR MOTOR UNITS LP SHP Fig.8 COMPRESSOR 2 a RHB REM TYPICAL WIRING - FOR MULTIPLE COMPRESSOR A UNITS C) () C) *SLP2 SHP2 SFP2 .Q—O7O—O0 e EJ Tt] Po es ee : e BLOCK, FUSE RHB RELAY, HEATER BLOWER NOTE BLOCK, POWER RLO RELAY, LOCKOUT QA OL |USED ONLY WHEN SUPPLIED WITH BLOCK, TERMINAL RTD RELAY, TIME DELAY "CL" COMPRESSORS. CAPACITOR SFP ‘SWITCH, FREEZE PROTECTOR CONTACTOR, COMPRESSOR SHP SWITCH, HIGH PRESSURE FIRESTAT SLP SWITCH, LOW PRESSURE OVERLOAD SRV SOLENOID, REVERSING VALVE PROTECTOR, THERMAL TR TRANSFORMER RELAY, BLOWER MOTOR —— FACTORY WIRING RELAY, HEATING * OPTIONAL ACCESSORIES 7 —-—— FIELD WIRING FORM NO 7871 7--78 System Return System Supply Condensate ‘ Flexible Hose SW-SWP Installation Detail Blower Motor Access Panel (this side) ——Return Air Filter UOUUUUUUUUUUUUUUUUD 20000000000000000000 0000000000000000000 oeo000000000000000000 0000000000000000000 YO000000000000000000 oo000000000000000000 Electrical Access Panel oe000000000000000000 0000000000000000000) 0000000000000000000) 000000000000000000 e000000000000000004 ANAANNNDODOOODOOOOON with P-trap. NOTE : Vent condensate Compressor Access Panel CA-O77-HERS APPENDIX IV: The test field was instrumented to record the thermal responses of the soil to the heat extraction. In this appendix we present biweekly plots of the soil temperature for the duration of the project. The location of the probes are shown on the diagram on the next page. Except for the probes between the pipes (labeled BIW) temperatures were recorded at depths of 1, 3, 5, 7, 9, 11, 15 and 20 feet. Between the pipes temperatures were only measured at 1, 3, 5 and 7 feet depth. In addition to the data plotted, temperatures were also measured along the pipes and along a horizontal transect perpendicular to the pipes at the point where the vertical probes were located and at the depth of the pipe. Brw + 2 q's i a . Far field 50 South Field 1 280 Arctic Health Parking L a Koyukuk Avenue North 82/01/15 SOUTH FIELD CTN. SOUTH FIELD BTW TEMP ¢, 82/01/38 SOUTH FIELD CTN SOUTH FIELD BTW "80205 ferr G 83/82/27 SOUTH FIELD CTN SOUTH FIELD BTW WEST FIELD CTN + D E p T H F T ray @ + FAR FIELD ; PARKING LOT TEMP ©, TEMP q ~ = 82/03/15 SOUTH FIELD CTH SOUTH FIELD BTW It + A @ ar CHVE!MGMsy 8 » PARKING LOT 32/03/38 SOUTH FIELD CTN SOUTH FIELD BTW TEM o + bo o Hot CoH vmMEse 8 + 8 FAR FIELD PARKING LOT TEM q 16 5 TEMP 82/84/15 SOUTH FIELD CTN SOUTH FIELD BTW FAR FIELD TEM C, 32/04/38 SOUTH FIELD CTN SOUTH FIELD BTW TEMP C 32/85/38 SOUTH FIELD CTN SOUTH FIELD BTW TEMP C. FAR FIELD PARKING LOT . TEMP ¢, TEM G 32/06/30 SOUTH FIELD CTN SOUTH FIELD BTW TEMP C. TEPC FAR FIELD TEMP 82/87/15 SOUTH FIELD CTN SOUTH FIELD BTW TEMP C 32/87/38 SOUTH FIELD CTN SOUTH FIELD BTW WEST FIELD CTN TEM C. 32/08/15 SOUTH FIELD CTN SOUTH FIELD BTW EMP G TEP C WEST FIELD CTN WEST FIELD BTW TEM FAR FIELD TEMP C 82/89/38 SOUTH FIELD CTN SOUTH FIELD BTW PARKING LOT 8 82/18/15 SOUTH FIELD CTN SOUTH FIELD BTW TEMP C. 32/10/38 SOUTH FIELD CTN SOUTH FIELD BTW 82/11/15 SOUTH FIELD CTN SOUTH FIELD BTW FAR FIELD . PARKING LOT TEM © 32/11/38 SOUTH FIELD CTN SOUTH FIELD BTW TEIP C 82/12/15 SOUTH FIELD CTN SOUTH FIELD BTW 82/12/30 SOUTH FIELD CTN SOUTH FIELD BTW 83/81/15 SOUTH FIELD CTN SOUTH FIELD BTW 33/61/30 SOUTH FIELD CTN SOUTH FIELD BTW TEM C. 13 1 -18 gcir S FAR FIELD TEMP C. 83/82/15 SOUTH FIELD CTN TEMP FAR FIELD ger 18 SOUTH FIELD BTW WEST FIELD BTW -19 TEMP G t ‘ + + + 4% cCHvmys + le a PARKING LOT TEM 33/03/15 SOUTH FIELD CTN SOUTH FIELD BTW TEM ¢, 33/83/38 SOUTH FIELD CTN SOUTH FIELD BTW TEMP C FAR FIELD PARKING LOT TEMP TEMP c 83/84/15 SOUTH FIELD CTH _ SOUTH FIELD BTW TEMP c, WEST FIELD CTN TEMP ¢ FAR FIELD TEMP c 33/84/30 SOUTH FIELD CTN TEMP C WEST FIELD CTN TEMP C FAR FIELD TEMP G SOUTH FIELD BTW TEP PARKING LOT fe gar q 15 83/85/15 SOUTH FIELD CTN SOUTH FIELD BTW My i es ral t a ct $ ra ct rR oP fa of t eh dt i + & ty Ped} AF 8 Sf ey 3 ret Heal a ms m TEES = ‘ lo m a a . a : s oy . g a a AM oer we te, lee a: » AW Oe Oo he = FE Fa Lae qo o a es A ad a < = & a ; oO. 0 2 gy 4 i a i f- it y e] & 7 I 1 o. b re a . bed + GR J i Aan i i ry tid Finy A npn ay " i fi i i a URA ke rT oe ; ss ~ oe = St oP Seen wa ‘ et " a 7 | m i a a uy : ts i i . z AM oe er wi Hie ; : © E a le » AM Ore we 5 = cf nn) s Ye et MN —~ Ls - LS Wm 5 rh 3 de he s i . + ae + : it eta a} Fx, Se ae ee re ee a ol st oe cn a dod + 2. ‘ nl te a” q. ai + Fin ny wy Ln] = i i ». AW oO be Lok S i) %. + g ty 0 o + + + id rep lf ch a © * 1 ¢ ” AM Oe Er he m 1 PARKING LOT FAR FIELD . i m iy an] ql AW oe Tt whe oO 3/86/38 SOUTH FIELD CTN EN “ja 4 we P C, ; = WEST FIELD CTN WEST FIELD BTW TEP C 83/07/38 SOUTH FIELD CTN SOUTH FIELD BTW TEP C JEP ¢ g a 83/98/15 SOUTH FIELD CTN SOUTH FIELD BTW TEP 93/98/28 SOUTH FIELD CTN 8 elr g, FAR FIELD 8 is SOUTH FIELD BTW THF ¢ 3 ! ~{9 “5 SOUTH FIELD CTH SOUTH FIELD BTW gelp q& . SOUTH FIELD BTW WEST FIELD CTH _ WEST FIELD BTW TEM ¢.