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Juneau Heat Pump Program Final Report 1982
JUNEAU HEAT PUMP PROGRAM FINAL REPORT JUNEAU WATER SOURCE HEAT PUMP PROGRESS REPORT KETCHIKAN HEAT PUMP PROGRAM PROGRESS REPORT Sponsors: Juneau, Alaska: Alaska Electric Light & Power Company Glacier Highway Electric Association USDOE Alaska Power Admininstration Ketchikan, Alaska: Ketchikan Public Utilities USDOE Alaska Power Administration August 1982 TABLES oo a FIGURES: Home Characteristics and Heat Pump Systenis..........+..- Monthly Energy USe..... eee ee cece eee e eee eee eee eeseeee Estimated Heat Loss In Five Study Homes........seeeeeeee Estimated Coefficient of Operating Performance (COP) For Six HOMES. ..ccccecccccccccccevccccesssessssssecene Energy Cost COmMPariSON.....eceeeesee eee reece eee eee eeeees Home and Water Source Heat Pump System Characteristics... Monthly Energy Use and COP...... cece cece ee eee teen eens Heat Pump COP's and Heating Degree DayS.........eeeeeeee Theoretical Heat Pump Family of Curves...........-eeeeeee ii 10 JUNEAU AIR SOURCE HEAT PUMP PROGRAM (FINAL REPORT) This section is the final progress report of a two-year field evaluation of eight residential air-source heat-pump installations in Juneau, Alaska area. Subsequent sections report on the progress of a water-source residential unit in Juneau, and several air-source units in Ketchikan. Introduction and Background The Juneau heat pump program began in 1979 and was jointly sponsored and funded by Alaska Electric Light and Power Company (AEL&P), Glacier Highway Electric Association (GHEA), and USDOE, Alaska Power Administration (APA). The idea of electric heat pumps for space heating in the Juneau area goes back several years. By the mid-1979's, heat pumps were becoming very popular in many parts of the United States--technology had improved and rising fuel prices made the technology an attractive alternative to many consumers. The national emphasis on oi] conservation and renewable resources probably assisted in the spread of the heat pump this at this time--but still more in Southeast Alaska. Studies commissioned by APA and AEL&P in 1978 confirmed on a theoretical basis that the heat pumps should be economically feasible for Juneau based on the oil prices prevailing in 1977. By the time the program was started, the question of economics of heat pumps versus oil was already moot. Oil prices were so high that the reoccuring questions were: 1. would the heat pumps operate satisfactorily in the area; 2. could they be serviced physically and economically; and 3. would they be acceptable to homeowners. The heat pump program was designed to check out these points. With the continual increase in oil prices, an even larger question emerged--Would people ignore the heat pump option and choose less efficient electric heating systems. A specific finding of the 1978 study was that heat pumps should be economically viable because nearly 70 percent of the yearly hours are in the 35° to 65° F range and require moderate heating. Based on 1978 fuel oil prices of 56¢ per gallon, estimated life-cycle costs of heat pumps about equaled costs of fuel-oil systems--$1,644 per year versus $1,566 per year and about two-thirds the costs of electric-resistance systems-- $1,644 per year versus $2,706 per year. Hydroelectric energy available from the Snettisham Project offers a practical and economically attractive opportunity for a long-term renewable alternative to fuel oil for space heat. Results of the 1978 study were discussed in a public meeting, and consensus favored testing the finding. AEL&P, GHEA, and APA jointly agreed to fund half the cost of installations, to a maximum cost of $4,000 each. Proposals for installation of units to be evaluated were solicited publicly from individual owners and builders interested in applications for new houses, and as modifications (replacement) of existing heating systems. Each individual was responsible for all sizing, purchase, and installation agreements with a supplier. An additional requirement was that structures be made more thermal-energy efficient than usual. Costs of this upgrading were included in the maximum reimbursable amount. All proposals submitted exemplified energy-conscious design and thoughtful attention to conservation principles. Some measures which were included to enhance heating-system operation and overall performance of the dwelling were additional insulation in the attic, ceiling, walls, and under the floor; less window space, thermally designed and appropriately sized; insulated double-door entries; fireplace-stack damping and heat screens; moisture-control vapor barrier throughout; insulated hot-water tanks and pipes; and passive solar design. Nineteen proposals were submitted. An evaluation board of community building, financial, Borough, and fuel-supplier representatives recommended eight proposals for selection within the total budget. Final selection was made by the sponsors in August and September 1979. The sponsors acknowledge the time and effort contributed by several individuals to the success of this program. A listing would be voluminous and probably incomplete, but would include: Eight homeowners Eleven unselected applicants Heat pump suppliers Heating and plumbing suppliers and contractors Homebuilders association Operation of Juneau units and introduction of the Ketchikan units have been reported previously by progress reports in May 1980, October 1980, January 1981, July 1981, and February 1982. Readers are referred to those reports for additional detail. Objectives The verification program proposed to determine whether residential heat- pump heating systems would operate in a technically and economically acceptable manner in the Juneau area. Sub-objectives were to determine the approximate total annual costs of heating systems in specific houses and to encourage better-than-usual energy efficiency in structures. Energy use, its analysis, and cost monitoring were not intended to be elaborately detailed. The basic information wanted was general system reliability, acceptance by the home owner, and a rough idea of annual costs. Specific comparisons with conventional heating systems were not intended, although generalized conclusions can be derived. Also, findings have been and will be used for estimating the effect on future electric power requirements of area-wide conversion from fuel oil to electricity for heat in both existing and new construction. Heat Pump Technology A thermodynamic law of nature is for heat to flow from higher to lower temperature. A heat pump mechanically causes heat to flow in reverse, from a low-temperature to a high-temperature region, by a compressor and compressible fluid. External energy is provided to the pump/compressor. A heat pump which typically runs on electricity works as a refrigerator. It transfers the heat in air at a relatively lower temperature to another place (such as a house interior) at a higher temperature. In this heating cycle, cool air outside the building is blown over an even colder evaporator coil. Heat from the outdoor air warms and evaporates a fluid refrigerant in the coil. The fluid refrigerant is then mechanically compressed and raised to a higher temperature. This high-temperature gas then circulates through condensing coils, over which air passes and warms as the refrigerant gas "gives up" heat and condenses. Then a fan blows warm air through ducts to the rooms to be heated. The ratio of thermal energy delivered inside the building as heat, to the external electricity supplied to the heat pump, is the coefficient of performance (COP). The COP is greater on mild days than on cold days because more heat is available in the outdoor air. The average COP for a year is the seasonal performance factor (SPF). In other words, SPF is a measure of the heating equipment efficiency over the total heating season; the higher the SPF, the more efficient the unit. An annual SPF of 2.0 or greater was expected in Juneau, with daily COP's being 3.0 or more. Commercially available heat pumps are both heating and cooling units. This is accomplished by reversing the direction of flow of the refrigerant and reversing the heating and cooling sequence of the cycle. This reversing cycle makes the heat pumps especially attractive in areas with both heating and cooling requirements and raises the annual SPF. Heat pumps work effectively in areas such as Juneau which theoretically require only heat. If there is no cooling requirement, there simply will be no any operation in the cooling-cycle mode. From a practical standpoint, on occasional warm days some of the heat pumps in thermally efficient houses are used for cooling. A commercial system outside the program has been installed specifically for cooling. Sizing a heating system depends on the thermal load characteristics of the building structure. A component heat-loss/heat-gain calculation (design heat load)is used to determine the extent of a building's loss of heat by transmission through its thermal envelope. As the outside (ambient) temperature drops and the heating requirement for the building increases, a point is reached where more heat is needed than the heat pump can prove to maintain the comfort level. This “balance point" is an outdoor temperature usually between 20° and 45° F, Supplemental heat is added by electric resistance elements or "strips" in the air makeup plenum of the heat pump. The strips are staged to activate in increments of heat requirement, usually 5 kW at a time (17,060 Btu per hour). They operate at a COP of 1.00, the same as resistance baseboard heaters and forced-air electric furnaces. The heat pump will continue to Operate at a COP in excess of 1.00 to temperatures of 0° F or below (usually to -5° or -10° F). However, as the COP decreases with outdoor temperature, the resistance strips are needed to make up the balance of the design heat-load. Theoretically the COP of the total system will be slightly greater than 1.00 at the design heat-load temperature because of the added mechanical advantage of the heat-pump refrigeration cycle. As a contingency, sufficient electric resistance strips are provided with most systems and sized to provide the total heating requirement exclusive of the heat pump itself. In this mode the unit would operate as a forced air furnace. Again, this is a standard commercial Practice not unique to Juneau. Some areas of the nation, such as the upper midwest, with colder temperatures than Juneau employ heat pump systems. Heat pump systems are available as both split and single-package systems. The main difference is for ductwork design and installation convenience. A split-system heat pump picks up heat from the outside air and transfers this heat to a refrigerant circulating through an exchanger, which in turn runs through insulated lines to an indoor condensor. The condensor is about the size of a conventional furnace. With a single-package system the entire unit (evaporator and condensor) is usually installed outside the foundation wall, with the heat-output side of the condensing coil connected with the plenum and air distribution ducts which pass through the wall. In these installations extra care is needed to seal off and insulate against outside-air infiltration. Installations The heat pumps are installed in houses throughout the greater Juneau area. All but one are multiple-level, wood construction of various sizes. Their living space averages about 2,031 square feet with an average heating requirement of 38,475 (513 Btu/hr/F°x75 F°--see Table 3) Btu per hour at design conditions of -5° F outside-temperature and 70° F indoor temperature. Buildings range from new to 60 years old. Heat pump capacities are rated in "tons", where one ton corresponds to freezing one ton of water per day--equivalent to 12,000 Btu per hour or 3.5 kWh. The program heat pumps are of three standard sizes: three-, four-, and five-ton capacities. All have built-in, electric-resistance supplemental heat which ranges from 20 to 25 kW. Table 1 shows characteristics of each installation. Installed costs of the heat-pump systems averaged $6,246. This included the heat pump, ductwork, electric service, and other necessary work to make the systems complete. The first system began operating in October 1979 and the last in May 1980. Operation Performance Electric Energy Each month, each utility electric service meter used for billing was read at the same time as a meter connected in series for the heat pump only. These readings do not coincide with the utility billing cycle. Monthly energy use data for the individual heat pump systems and the total home electric use is tabulated in Table 2. cop Data obtained from monitoring were used primarily to determine the COP of each unit. This was done by comparing the amount of energy required to operate the heat pump with the energy (heat) output. Energy output was determined by evaluating the heat-load characteristics of each structure, and heat input sources gains other than the heat pumps (such as passive solar, wood stove, electric lights and appliances, occupants, etc.). Heat-load calculations were made on six houses (sufficient data were not available on the other two). Several assumptions were made to complete the theoretical analysis, these are explained in the Appendix. Table 3 summarizes the heat loss (Btu/HR/F°) for the six homes evaluated. The temperature differential was 27 F° (inside 68° F, outside 41° F). Multiplying the unit heat loss rate by the monthly heating degree days gives the total structure heat loss (heat gain required by all sources). Heat gain supplied by the heat pump (calculated as explained in the Appendix), divided by the energy consumed by the heat pump, results in the COP's in Table 4. Heating degree days during the study and long-term averages are also shown in Table 4. The average study home COP is plotted in Figure 1. As expected, this curve roughly parallels the heating degree day curve. In Figure 2, a family of curves is developed for homes with differing heat losses. As the weather cools (monthly heating degree days increase), more kWh are needed by the heat pump to meet the heat load of the building. The curves indicate the electricity required for different heat loads at different times during the year. Three factors must be kept in mind when reviewing the kWh used for heating energy used, and the average COP's. First, the average heating requirement during the 25-month data period was about 93 percent of the long-term requirement based on heating degree days (702 actual versus 751 long-term average heating degree days per month). Adjustment to the JUNEAU HEAT PUMP PROGRAM TABLE 1 HOME CHARACTERISTICS AND HEAT PUMP SYSTEMS Heating Boreowner Design3/ Living Window Heating ! Balance System (spoasor) temp. Home area area design Upgrade system Model Capacity point = CostL/ Location (°F) characteristics (sq ft) (sq ft) load components type No. (°F) «s) (BTU/hr) (fbr) BearD 2/ Starr Hill -3 60 yr. wood 1,440 - 30,172 - Westinghouse HPO30D 24 ton 30 $5,640 (apa) 70 frame 2-story split (8.5 kW 30,000 BTU) simvoxs 2' Highlands -5 44 yr. wood 2,240 - 81,753 - York cHPO6O 5 ton 237,707 (apa) 70 frame 2-story split (17.6 kw and 2-story 60,000 BTU) 31 revit 2! Glacter -20 44 yr. wood 1,796 160 68,000 R19 walls Trane BPH B 4 ton 153,500 (AELEP) Village 70 frame 2-story R-30 split 352 (14.1 kd ceiling 36,000 BTU Dbl. pane windows STAUTFER Lemoa Creek “15 New tri-level 2,344 - 44,500 R-19 walls York SHP606A S ton 23 6,975 (apa) 70 chalet wood frame R-30 single (17.6 kW ceiling 60,000 BTU) Solid core doors Donble pane windows TONSMEIRE Douglas -10 New house 2,500 - 55,000 R-19 walls York SHP606A 5 ton 23° (7,450 (aPa) 75 2eestory R-38 single (17.6 kW wood frame ceiling 60,000 BTU) Triple pane windows Lakewood -10 New 2-story 1,584 152 53,939 - R-19 walls Coleman’ CHPO-48 4 ton 18 6,700 70 wood frame R+38 ceiling split (14.1 kw Double pane windows YOUNG Montana - New 24-story 1,800 120 53,800 R-19 walls Westinghouse HP0-36 3 ton 30 4,900 (GHEA) Creek chalet wood frame R-39 split (10.5 iw ceiling 36,000 BTU) Double pane windows R-14 foam under slab MCGREGOR Lakewood -20 New single story 1,650 - - - Day & night - - 23° 7,100 (AELSP) , AVERAGE 1,919 $6,246 2/ Retrofit home 3/ Beating degree days is 9,076 for all homes. 4/ Auxiliary heat racing 4s 20-75 kW for all units. L/ Heating system cost (heat pump, ductwork, wiring, controls) TABLE ¢ MONTHLY ENERGY USE Neating Uegree Vays A Beard Venton Levitt McGregor Simmons Stautter Tunsmeire Young Average rea en is Sq.Ft. 1,440 1,584 1,798 1650 2,edu 2,348 3,400 1 ,guu Total Neat 441.0 (452.84) 739.27 $23.53 551.11 (569.2) 963.73 Loss Beusiirs Year/ Month 1979 Oct np(heat pum) (KWH) 596 mg th(total mouse) (KWH) Nov hp 1,700 1,700 28 975 th vec np 1,190 1,167 th 1980 JAN hp 960 2,130 1,658 1,583 1,404 1,267 tn 2,180 27180 Fee Kd +208 2h B95 1,036 198 2A MAR U89 np 1.550 1,208 297 949 1,026 th 189 812 1,447 1,483 APR np 754 683 830 2,160 1,725 1,230 678 783 mm Laee 696 1,533 2,981 2,282 1,709 hp 372 308 1,299 1,042 1,000 804 an 564 a 968 a4 1,729 145751884721 1,375 np 18a 204 570 397 581 387 278 384 th 4,080 278 185200 1,378 1,253 LL 1,188 hp 138 536 385 267 459 387 283 288 om 648 «1,154 1,393 1,867 1,173 1,077 1,126 1,205 hp 288 330 473 310 440 1,170 388 308, 332 th, 10st 986 1,234 976 1,075 1,063 taut 1ozé 1,081 np aay uy 650 5u5 113 239 542 N61 al4 the 1083 275 1,770 3,976 12481500 eSZ LO? 1I38 hp eg e2l Ju 838 955 47500777 oa n9 th EAS Nuk 17068 2,709 142321 1,380 1,765 hp 1,357 10089 : 1,sbu 739 166 95 th = 2,UsU geld 1834 c¥y 865 wae Lull vec np 3,896 by 06 = 4,078 Lae 13st 1,169 th 4.656 3,' S.beh 635K 1,396 $,/31 2,5ud Summary Kit/yr 19tU bi 9,370 16 eS Aad 9,007 1981 JAN hp 1,328 830 2,599 997 1,769 1,536 $531,373 839 1,287 th 1,832 «1,976 3,079 3,818 = 1,489 2,500 2,643 1,558 2,362 FeB hp 1,558 1 3,608 1,229 2,322 2,151 744 1,840 899 1,036 th 2,083 2,528 1,293 4,878 = 1,511 3,028 = 3,225 1,460 2,501 MAR np 982 974 2,748 720° 1,209 1,629 504 1,266 786 1,026 th 1,475 2,107 2,056 3,413 1,475 1,892 2,537 1,350 2,038 APR hp 1,178 992 1,656 1,240 «1,779 1,764 509 1,303 773 783 th 3,767 2,183 1,716 2,809 1,965 2,468 = 2,348 1,289 2,068 may hp 519 359 aze 464 485 1,053 130 545 394 564 th 1,048 1,541 2,018 1,969 903 1,107 1,501 396 1,373 JUN ho 443 264 731 215 448 752 476 316 354 th 1,284 366 1,819 1,879 984 1,554 1,138 904 1,241 Jue hp 302 214 503 306 309 163 399 269 288 th 751 1,102 1,728 1,736 1,013 910 «1,795 1,016 1,256 NG ne 287 183 833 $37 378 699 486 275 332 th = 1,073 922 1,184 1,909 1,191 1,147 1,600 856 1,235 sep ho 796 6u9 1,087 639 1,294 1,206 938 469 ara th «1,825 1,827 2,168 2,761 1217 2,140 2,318 993 1,868 ocr hp 865 662 1,500 866 1,068 1,102 682 ng th «1,416 1,488 «1,514 2,858 1,026 1,962 L3LL 1,745 nov hp 1,333 1,330 1,758 117418512, 155. 1,600 838 975 th 2,106 2,385 1,930 3,360 1,771 2,860 2,928 1,388 2,341 o€C hp ‘ 2,240 3,767 2,650 2,264 3,252 2,835 1,167 1,169 th 3,098 4,753 3,297, 3,248 4447 1,773 3,453 Syamma 21,614 11,037 15,863 18,028 15,293 7,707 9,007 th 21,983 3,143 -17,840 25,243 28,439 25,930 1982 JAN hp 2,662 5,378 5,294 3,810 1,579 1,287 th 7,346 3,473 5,823 6,386 5,045 Fes hp 1,52 3,053 4,963 2,832 1,214 1,036 th 5,545 2,102 sll 5,987 3,921 MAR hp 940 2,085 1,887 1,552 1,021 1,026 th 3,205 1,664 = 2,820 2,806 2,477 APR hp 1,008 2,223 2,022 1,661 837 783 th 3,662 1,784 3,022 3,007 2,700 Total Wd 16,151 th Year-Round Average KWHl/yr hp 14,180 9 6a 21614 12 ,4RH 19,252 19,457 16,102 #,a22 9,007 th 22,U94 20,249 WAS IRLOK/ aw S1Z 30,20 25.009 Normal HOO Year May Bl - April Ne KWH/yr myo i; ebay tld 9061-9007 th oa ul? Average Area Sq. Ft. 0 a9 2,284 2,061 TABLE 3. ESTIMATED HEAT LOSS FIVE STUDY HOMES Percent of Total Tonsmeire Beard Simmons Stauffer Young McGregor Avg. Walls 24.3 25.4 22.4 24.8 33.2 28.7 26.5 Ceiling 12.3 16.1 8.2 10.4 9.2 12.0 11.4 Windows 22.3 17.1 22.1 23.1 24.1 14.5 20.5 Doors 2.8 3.9 1.6 7.8 2.9 2.0 3.5 Ground 17.8 12.5 26.7 12.2 16.1 30.7 19.3 Infiltration 19.5 24.5 18.9 21.6 14.5 12.1 18.5 Total | 100% 100% 100% 100% 100% 100% Btu/HR/°F 551 441 739 524 369 453 525 The average monthly COP's ranged from 1.20 (in December 1980 when the average outside monthly temperature was 21.9°) to 2.79 (in August 1980 when the average outside monthly temperature was 49.1°). seasonal operating performance was 2.05 for the 25-month monitoring period of valid data (4/80 through 4/82). TABLE 4. FOR SIX HOMES The average ESTIMATED COEFFICIENT OF OPERATING PERFORMANCE (COP) Heating Tonsmeire Beard Simmons Stauffer Young McGregor Avg. Degree Heat Loss 551 44) 739 524 369 453 513 Days Month COP COP COP COP COP COP COP Actual Avg April ('80) 1.86 1.86 678 783 May 2.16 1.96 2.06 477 = 564 June 2.44 2.05 2.00 2.16 278 354 July 2.91 3.08 2.18 2.72 253 288 August 3.42 3.06 1.89 2.79 308 332 September 2.04 3.02 3.15 2.12 2.58 461 474 October 1.87 2.40 3.01 2.11 1.35 2.15 614 719 November 1.78 1.65 -- 1.84 2.61 1.97 766 975 December 1.91 1.04 -- 1.19 0.65 1.20 1,331 1,169 January('81) 2.06 1.86 3.00 1.53 1.30 1.95 839 1,287 February 1.68 1.82 2.90 1.46 0.88 1.75 899 1,036 March 2.00 2.49 2.85 1.77 1.08 2.04 786 1,026 April 1.81 1.96 2.85 1.64 2.01 1.63 1.98 773-783 May 2.03 3.06 2.99 2.74 3.55 1.98 2.72 394 564 June 2.02 2.89 3.15 2.41 2.08 2.51 316 354 July 1.99 2.99 3.89 2.72 2.14 2.75 269 288 August 1.92 2.61 2.70 2.15 2.03 2.28 275 = 332 September 1.91 2.01 2.98 1.69 1.64 2.05 469 474 October 2.13 1.93 2.73 1.66 1.14 1.92 682 719 November 1.66 1.58 2.78 1.75 1.25 1.80 838 975 December 1.43 * 2.50 1.77 1.07 1.69 1,167 1,169 January('82) 1.27 1.47 1.15 1.30 1,579 1,287 February 1.07 1.47 1.61 1.38 1,214 1,036 March 2.03 2.19 1.66 1.96 1,021 1,026 April 1.74 2.09 1.47 1.77 837 783 * Meters changed; readings not available. 10 HEAT PUMP COP'S & HEATING DEGREE DAYS FIGURE 1. x skeq aa180q 3utT ea % a d T]e9OH Fa ° wo z wn oO wn oO wy Oo wy cr N 8 hay 8 a 5 = SIE SU SVE = He vO TAIL POEL 1 HT sree En PL ere Uf EU oa a nil UIT TINI T iT an 1 Teta ; i PT sony ! i t i ! | } : al] i ! 1 las ul a STU ee IA pt ops i N | rie 1 + a be 00 aL ay ~~} MEE ! val . Se TEL ho 01 wo . 1 Be | ao | Q |} | o eit bh o ae aE + as bo } 5 py on oO v ;o o o | a = 3 ai i j No rail a i a t —+4-— ~ + 4 _|oo a o 1 ie Ve! a > . y i a i | iia : vost | i 7 ; ih +P : : ia i ; i : | | | “STS | i {er Vay Ml see EA ee et ee am ul eae ROLLEI Eee Heth i | ee TR EL eS Sc Deets eI it Qe y S a °o ° fo} il = i oo a a H i doo dumg jee fl --HEATING DEGREE DAYS PER MONTH-- FIGURE 2, THEORETICAL HEAT PUMP FAMILY OF CURVES HEAT PUMP kWh USE vs HEATING DEGREE DAY PER MONTH (65° base) Colder 2000 Heat Pukp Home : 3 ym, Heat Pump Home Heat Pump Hom 1500 350 Btu/HR/°F 525 Btu/HR/°F ; 700 Btu/HR/°F 1000 | 500. I Warmer 0 cn a EE 500 1000 1500 2000 2500 3000 3500 4000 4500 Heat Pump kWh/Month 12 long-term average would increase the kWh used and probably slightly decrease the heat pump COP because of increased use of supplemental heat strips during coldest months. This increased supplemental heat could be reduced by installation of load management controls. Second, the average COP is based on the simple average monthly COP's of the units with reliable data without regard to eliminating data for units known to have problems. Specifically, the Young and McGregor units are detrimental to the composite COP. The Young home was mainly heated with wood for several months (see Appendix) with the heat pump used to supplement the wood. After the inefficiency of this method of operation was discovered, the practice was discontinued. The McGregor unit Operated for several months with a defective (slowly leaking) refrigerant system before it could be repaired. Excluding the Young and McGregor data would result in a composite COP of 2.24, weighted for a year-round average. Third, wind is an unquantified variable. The thermal blanket provided by calm air about a structure is disrupted during windy periods, causing a slightly lower external temperature (steeper energy gradient). This can amount to four or five degrees farenheit at extremely low Juneau temperatures (-10° F to -20° F). More significantly, wind causes increased infiltration by overpressures on upwind surfaces and openings and by increased exhausting on downwind (low Pressure) surfaces and openings (such as stacks and vents). More cold, infiltrated air must be heated. Therefore, windy days have higher heat loads and COP's than calculations show. During high winds, infiltration could as much as double the heat load of calm periods. The original estimate which determined a yearly COP of 2.2 for Juneau appeared to be correct--proper system design and improved heat-pump technology would increase this value, whereas poor installation and system design would lower the COP. Proper installation cannot be overemphasized. A brief comparison was made with energy consumed by other houses with heat pumps not in the program. Average energy consumption of eight residences selected at random within the AEL&P service area was 25,000 kWh in calendar year 1981 (average 2,080 kWh per month). The same year, the eight program houses averaged 23,500 kWh (1,960 kWh per month). Heat-pump energy alone was not monitored in the non-program houses. Some of the non-program homeowners have voluntarily monitored their systems and reported that cooling was used parts of some days during May and June 1981. Non-program homes included both new and retrofit systems. Operation Cost and Savings The total cost of a heating system includes investment, annual energy, and annual maintenance costs. Based on data from the heat pump program, these costs have been estimated for heat pump, electric resistance, and fuel-oil hydronic systems. 13 Investment costs were obtained from homeowners (heat pumps) and suppliers and contractors (resistance and oi1). Energy costs were computed based on heat pump program data, and information from suppliers of other energy. Maintenance costs were based on supplier's estimates. Heat pump owners have not reported maintenance costs during the past two years--this is assumed to be because suppliers bore start-up adjustment costs and service requirements have been minimal but will increase during the next few years. Energy costs of comparative systems (based on average heat pump preference of six homes) are shown on Table 5. Electric rates and fuel-oil rates are those in effect during July 1982, and reflect recent utility increases. Operation Problems, Homeowner's Comments, and Other Observations In general, the program's heat pumps have had few operational problems and owners are satisfied. Some minor problems were detected in early installations. These were corrected, and modifications made in subsequent installations. A few major mechanical problems did occur and immediately became evident. All were covered by warranty. Maintenance calls and costs have not been reported except for a few instances. Original service estimates were about $100 per year. The conclusion is that most units have required little or no service except minor items such as filter changing by the owner, but service will increase (or be periodic) after the first two years of operation. ° Four homeowners (two in the program and two others in the Juneau area) reported icing on exterior coils of split units early in the program. Locating the outside unit or in shade seemed to be the problem. By relocating the liquid line sensor the units defrosted properly avoiding the ice-up conditions. ° Early in the program one unit (Stauffer's) failed requiring the resistance-heat elements to carry the full load during the winter months and operate as an electric forced-air furnace. At no time was heating required beyond the heat-pump system itself (such as wood stove, fireplace, or space heaters). ° As pointed out earlier, the McGregor unit froze during January, February, March, and December of 1981, due to lack of charge in the refrigerant coil. A slow leak caused this. The heat pump operated on backup electric resistance during the months of freeze-up, lowering the annual heat pump-unit efficiency to a COP of 1.5 during 1981. TABLE 5. ENERGY COST COMPARISON 14 Annual Equivalent Equivalent Totai Seasonal Heat Pump Annual Annua! Equivalent deat Heat Energy Electric Heat Fuel Oil Annual Fuel Qi] Loss Loss(1) cop Cost(2) Energy Cost(2) Energy(3) Energy Cost UST.25/GaT 0$1.507ga (BTU/HR/F?) (10°Btu/yr) (3) ($) (Gal) (s) (s) (. Temp ,F°] Bearc 441 93.87 2.27 622 1,375 1,046 1,308 1,569 [24.3] 660 1,466 Simmons 739 146.30 2.87 747 2,143 1,631 2,039 2,446 : (22.6) 792 2,272 Stauffer sed 127.61 1.89 989 1,869 1,423 1,779 2,134 [27.3] 1,048 1,982 Tonsmeire $5i.12 130.35 1.97 969 1,916 1,454 1,818 2,181 (27] 1,027 2,029 Total 2,255 498.13 8.94 3,327 7,297 5,554 6,944 3,330 (101.7) 3,527 7,736 average fés 124.53 2.24 832 1,824 1,388 1,736 2,082 125.4] 882 1,934 (i; 19 (2) 3 (AEL&P)/KWH; 3413 Btu/KWH 3 SHEA) /KwH; 3413 Btu/KWH (3) $65 ‘cfency Energy Cost Comparison--$ Annual Savings Realized Using Heat Pump Rather Than Electric Resistance oil 011 ($1.25/Gal) ($1.50/Gal) Seard 753 686 947 798 648 909 1,396 1,292 1,699 1,480 1,247 1,654 880 790 1,145 934 731 1,086 Tonsmeire 941 849 1,212 996 790 1,153 Totai 3,970 3,617 5,003 4,208 3,416 4,802 Average 992 904 1,251 1,052 854 1,200 15 oO Several units were fitted with fan guards which keep ice, snow, and rain from striking the fan blade. Cold rain (near 32° F) striking moving fan blades causes immediate heat loss (from water drops) and ice formation on blades, resulting in an out-of-balance condition. Standard factory retrofit covers (at no cost to the homeowners ) corrected the problem. Homeowners have provided the following observations. Oo Evenness of heat distribution in contrast to previous "hot" and "cold" spots (noticed especially in the retrofit homes).* Oo Home moisture problems seem to be absent. Experience from this program indicates that moisture levels are lower because heat pumps circulate more air throughout the structure. oO Return air-duct intakes should be located to avoid dusty locations. One homeowner had to move a return intake which was originally located in the workshop. Sawdust from the workshop tended to clog the heat-pump filters. 0 Several units switched to the cooling mode during the warmer summer days. ° No noise problems have been reported by homeowners or neighbors. 0 In multifamily installations extra care must be given when sizing ducts and installing thermostats.** 0 Juneau residents have contacted some heat pump homeowners. Although information about the demonstration installations is public information, the sponsors ask that interested people remember that personal residences are involved and the homeowner's privacy should be respected. * A consistent comment by homeowners since the beginning of the program. This is characteristic of heat pumps because a larger volume of air is circulated. Conventional forced-air systems blow lower volumes of higher-temperature air and radiant systems do not use air; these often result in "hot" and "cold" spots. Also, heat pumps tend to prevent warmer air from rapidly rising and collecting in higher spaces. Homes with high ceilings benefit by having warm air circulated back to lower levels. ** A common arrangement in Juneau is a multistory, multifamily structure. Heat-system design must consider the effects of heat rising from lower to upper levels and allow for independent temperature control for different units. Oo Locating the outside unit south of the house would provide the highest efficiency, but some installations are on the north side to reduce the noise and protect the unit from damage. This results in additional snow and ice accumulation around the unit; such units should be elevated at least one to two feet above the slab. During cold weather, the defrost cycle results in ice buildup at base on some units. An aluminum stand 1'6" above the slab costs about $100. 0 Unless installer has proved experience with fiberglass ductwork, use sheet metal. Some ducts have had to be retaped. ° One type of unit has a mercury switch that activates auxiliary resistance heaters whenever the thermostat setting is about 4° F above inside temperature. This results in increased costs if thermostat is set low at night and increased in the morning. One owner has chosen to leave the thermostat at one setting, but some have disconnected the auxiliary heater control. Other control settings adjusted by one owner were defrost-cycle time (30, 40, and 90 minutes) and defrost-termination temperature. These were adjusted to minimum time and maximum temperature during the past winter to help reduce the icing problem mentioned above. oO One owner reported the only regular maintenance was cleaning the filter in the inside unit. Defrost-activation controls were repaired under warranty soon after installation (January 1980), and the system had to be recharged in 1982 due to a leaky Schrader valve at the outside unit. The latter problem also may have been due to the icing around the base this past winter. The valve just needed an adjustment. One man worked less than one hour to recharge the system (no bill at time of writing). 0 In summary, a retrofit owner reported satisfaction with most aspects of the heat-pump system, but there are some details of the installation that he would have changed. 0 One homeowner (Young) used a significant amount of wood for heating during 1981, and two other homeowners used a small amount of wood one month. Many homes in Juneau use wood as a secondary (or backup) heat source. Heat is gained also from electrical appliances inside the homes as in most homes. The amount of wood used for heating plus appliance heat all have an effect on the amount of heat required from the heat pump. Youngs heat use was: 1981 3 Jd oA S 0 N D J F M A M semi-dry spruce (ft~) 0 10 32.5 20 20 77 45 52 40 21 5 kindling (Ft?) 0 16 11.25 3 3 8 7 10 15 3 2 otal equivalent kWh 0 2 65 65 147° 175 1 63 20 16 17 ° During this period, wood was the primary heat resource for the thermally efficient house. The heat pump was essentially used for "peaking," which caused very inefficient performance (refer to Table 4) though the total electricity used for heating was low. This practice was discontinued after energy use was analyzed; it is noted for others relying on wood. 0 Some units were initially operated with night setback--lowering the thermostat at night and raising it in the morning. This practice initially appears to save electricity but actually does not if other controls are not used. The reason is a demand on the unit to suddenly increase indoor temperature causes supplemental resistance to come on, at low efficiency (the same as resistance heat--1.00). Wholesale suppliers and installers recommend against this, and homeowners have discovered constant temperature is preferable for comfort and economy. Automatic or programmable controls are available to allow temperature setback and increase over a period of hours using only the compressor. Effects On Juneau Power Requirements Drawing a firm conclusion about the effects of heat pumps on future power requirements is difficult, but there is no doubt that heat pumps have dampened and will dampen the increase in energy use for new and retrofit electric space heat. The largest uncertainty is the number of structures (residences and commercial buildings) that will install heat pumps. A second uncertainty is the amount of energy that commercial buildings will use (new residential use can be estimated from this program). As of spring 1982, there were approximately 175 heat pumps operating in the Juneau area. This included about 150 residential units and 25 commercial. Most of these were installed during a two-year period (1980 and 1981). About 975 all electric (electric heat) services were connected during this same period, making heat pumps 18 percent of the electric heating systems. APA and the utilities expect this percentage to increase, but heat pumps will probably remain less than half of the new electric heating systems during the next few years. Current projections are for about 360 new residential services during each of the next few years. An indication of possible electric energy savings by using heat pumps instead of resistance heating systems in residences can be illustrated by the following computation: Heat pump heating energy 19,800 kWh/yr/res (5/81-4/82 long term average HDD) Heat pump COP (5/81-4/82) 1.84 Equivalent resistance heating energy 36,400 kWh/yr/res Energy saving (resistance less heat pump ) 16,600 kWh/yr/res Total energy saving assuming 50% penetration and 360 new services 2,990,000 kWh/yr Round 3 million kWh/yr This 3 million kWh per year reduction in heating energy increase would amount to about 15 million kWh per year reduction in 1985-86, roughly 13 percent of the projected total annual Juneau area increase from 1982-1986. Energy savings of 15 million kWh would be about 6 percent of the 1986 area total requirement. Comparing the heat pump program houses with a group of all-electric resistance heated houses in the new Lakewood subdivision area indicates the resistance houses are not using quite as much energy as expected, which would mean that potential energy saving due to heat pumps would be less than the 46 percent (16,600 kWh/yr/res + 36,400 kWh/yr/res). Conversely, the COP of 1.84 derived from a simple average of all heat pumps in the program is conservatively low because units known to be operating inadequately and ineffeciently were included. Other qualitative obeservations about resistance and heat pump residences that support retaining a heat pump COP 1.84 as a valid and conservative value are: 0 area-wide energy use statistics for electric-resistance residences include small structures, such as apartments, condominiums, and mobile homes which are smaller than the heat pump house. New houses (of all types) are larger than the area-wide average. ° resistance systems are being managed by the homeowners by reducing temperatures in infrequently used rooms. 0 many homes using resistance heat also burn wood for supplementary heat. 0 heat-pump systems are operated at a more constant temperature, and this temperature is maintained throughout the structure for comfort and ease of operation. ° some definite attempts at load management have been made by a few resistance owners, including heat storage. This would theoretically affect only demand (kW) and not energy (kWh). Seven commercial buildings are using heat-pump systems. These include two restaurants and five small office buildings, and are 26 percent of the 31 electrically heated commercial buildings in Juneau. Heat pumps are not monitored, and no estimate of COP or heat in relation to building size has been made. During the past year (CY 1981), the seven heat-pump buildings averaged 20,900 kWh per year. All commercial all-electric customers averaged 26,900 kWh in CY 1981. For the period May 1981 through April 1982, a period of normal heating degree days, the number of all-electric commerical customers increased from 10 to 31 and averaged 33,900 kWh per year. This includes a mix of resistance and heat-pump installations. Heating energy should be a smaller percentage of total building energy use in commercial than in residential structures, but no analysis has been made. Potential for commercial all-electric heat seems undeveloped and growing rapidly. With only 31 of approximately 1,100 commercial customers using electric heat, the stage of electric-heat use now is similar to the stage of residential all-electric heating early in 1979. Residential electric-heat customers increased from 56 in 1979 to 1,100 (14 percent) in 1982 of a total of 8,100 customers. Commercial customers could increase similarly. Conclusions Heat pumps have proved to be a technically and economically viable heating mechanism for use in Juneau and Southeast Alaska. They are preferable to electric resistance heat since they use energy sources more efficiently. Specific statistical data are presented throughout the foregoing report, most significantly: 0 Average annual and monthly energy use is: Total House Heat Pump Period 1/80 - 12/81 Annual 25,800 KWH/yr_ . 16,100 KWH/yr (93% of normal HDD) Monthly 2,150 KWH/mo 1,340 KWH/mo Period 5/81 - 4/82 Annual 29,100 KWH/yr 19,800 KWH/yr (99.5% of normal HDD) Monthly 2,420 KWH/mo 1,650 KWH/mo 0 Life-cycle cost and savings of different heating systems: Energy Total Annual Required Energy Annual Savings Per Year Cost Cost* of Heat Pumps Heat Pump --AEL&P 16,100 5.0 ¢/KWH $1,984 -- --GHEA 16,100 KWH 5.3 ¢/KWH $2,033 -- Resistance--AEL&P 36,500 KWH 5.0 ¢/KWH $2,350 $366 --GHEA 36,500 KWH 5.3 ¢/KWH $2,460 $427 Fuel Oi] -- 1,388 gal $1.25/gal $2,486 $502 $453 -- 1,388 gal $1.50/gal $2,833 $849 $800 * Includes investment amortization and maintenance in addition to energy. 19 Average annual COP for 1/80-12/81 (93% of normal HDD) was 2.24 Average annual COP for 5/81-4/82 (99.5% of normal HDD) was 1.84 Heat pump systems appeared to use about 55 percent less energy than comparable resistance-heated residences during 1/80-12/81 period (93% normal HDD) and 46 percent less during 5/81-4/82 (99.5% normal HDD). Data show that resistance heat is intentionally regulated by owners to conserve energy whereas heat pumps are operated at fairly constant temperature for comfort and convenience. Also, heat-pump units are not designed to be zone-operated like electric resistance systems. This means that constant-temperature heat-pump operation is acceptable comfort and cost wise. Special designs for automatic or load-sensing controls could reduce demand and increase energy efficiency. Additional work needs to be done to optimize heat pump efficiency and load management to reduce peaking demand. 20 21 JUNEAU WATER SOURCE HEAT PUMP PROGRAM (Status) In late November 1981, a water-source heat pump began operating at Ken Ryal's residence at one mile Lena Lood Road. The Northrup VWTA-65 (71,000 Btu) unit was installed by Mel DeHart of Jack's Heating and Plumbing. Characteristics of the design are outlined in Table 6. A closed 500-foot loop of 14-inch PVC pipe runs from the home down the beach to a 300-foot pipe coil buried below low-tide level. The pipe then completes the loop back to the house where the water-source heat pump is located. Propoylene glycol fluid (nontoxic antifreeze) inside the PVC pipe absorbs heat from the ground and sea water, carrying it back to the house. This fluid is pumped through the coil by a one-horsepower Jacuzzi pump. Available data and COP computations are presented in Table 7. Incoming fluid temperature ranges from 38° F to 40° F. Demand for the total home was 16 kW during December, and 20 kW during January and February. The heat pump supplied all the heat load during the cold months. Night temperatures seemed to be more stable; during the day, large erratic solar gain through large south-facing windows, resulted in short cycle times. Another seawater unit is scheduled for the Indian Cove area within the next few months. TABLE 6. HOME AND WATER SOURCE HEAT PUMP SYSTEM CHARACTERISTICS 22 Homeowner Location Design Home Living System Model No. Temp. Characteristics Area °F, (sq. ft.) Ryals Lena Loop Rd 35-150 Wood-frame 1 story 1,350 Northrup VWTA-65 R-19 Wall 5-Ton R-28 Ceiling 30% window area CAPACITY BALANCE PT HEATING SYSTEM COST (71,000 Btu/hr) 45°F 14,830 TABLE 7. MONTHLY ENERGY USE AND COP December 1981 January 1982 February March April May Energy Use - KWH coP Total Heat House Pump 3,967 2,787 1.83 5,344 3,699 2.33 4,596 4,014 1.42 1,762 1,284 508 KETCHIKAN HEAT PUMP PROGRAM (Status) Table 1 in the Ketchikan Public Utility (KPU) report describes the Ketchikan heat-pump installations; Table 2 in the KPU report shows their electric consumption. In 1981, Ketchikan Public Utilities in cooperation with Alaska Power Administration, initiated a heat pump program. Eight of eleven participating units have been installed and are operating. The Ketchikan area has substantially less heating requirement than Juneau--6,885 versus 9,007 heating degree days. Following is a status report prepared by KPU. 23 24 KETCHIKAN PUBLIC UTILITIES 334 FRONT STREET XPKCK BOSOF AGS KETCHIKAN, ALASKA 99901 TELEPHONE 907-225-3111 MUNICIPALLY OWNED ELECTRIC WATER PHONE June 30 ’ 1982 U. S. Department of Energy Alaska Power Administration P. O. Box 50 Juneau, Alaska 99802 Attention: Mr. Floyd Summers Subject: Ketchikan Heat Pump Program Progress Report No. 2 Contract No. 85-81AP10026 Dear Floyd: Attached for your information and use are the following documents produced as part of the Heat Pump Program:—: TABLE 1: Heat Pump Installations a TABLE 2: Electrical Consumption Data TABLE 3: Status Report of TABLE 4: Heat Pump Program Purchase Order Data:: - APPLICATION: No. 14 Palmer = APPLICATION: No. 15 Ellison As indicated in Table 4, all of the original $30,000.00 allocated to the Heat Pump Program is now committed. There are a total of eleven participating heat pumps. Of these, eight are completely installed and operating. Of the three exceptions two, Hutton and Newell, are installed and have been successfully tested but require additional work to the electrical service entrance or building wiring; the last, Ellison, is a new home just beginning construction with a scheduled completion of October, 1982. No attempt will be made to calculate coefficients of performance (C.0.P.'s) before more data are available. However, the following observations can be made: (1) Some installations came through an unusually cold winter very well: Nickels, Bambauer, Ketchikan Air Service, Boles; some not so well: Grainger, Lewis. (2) The Lewis installation has experienced extremely high electrical consumption and has required several service calls. There has been continuing dialogue with the Owner, Contractor and Tenants to resolve the problem. Early indications are that the heat pump is undersized for the Mr. 25 Floyd Summers Page Two June 30, 1982 (3) (4) conditions and the house is not sufficiently insulated and weathersealed. A full report will be forthcoming. The Grainger residence has experienced high electrical consumption but, according to Mr. Grainger, his current cost of heating is "comparable" to his previous oil heating costs. Moreover, heat pump heating has proven to be considerably more uniform and comfortable throughout the house. Mr. Grainger has been advised of several recommended energy conservation measures as identified in a State Energy Audit of his home. An important observation is the greater need with heat pump heating for a balanced relationship between heating capacity and heating load. In an oil heating system this relationship is approximately linear over moderate imbalances. In other words, a 10% increase in heating load will be balanced by a 10% increase in fuel consumption. Whereas, with a heat pump; a moderate imbalance resulting from, say sub-standard insulation or "kicking up" the thermostat first thing in the morning, results in sharply higher energy consumption for awhile because of a change in heating mode from compression-expansion (heat pump) cycle to straight electrical resistance. Consequently, it is much more important with a heat pump to have a well insulated, tightly sealed home and to operate at a constant thermostat setting. Very truly yours, KETCHIKAN PUBLIC UTILITIES Patrick D. Malon Utilities Engineer PDM:cjdj Attachments cc: Robert E. Arnold, Utilities Manager Mayor §& City Council KPU Advisory Board Heat Pump Program Participants TABLE 1 Heat Pump Installations Ketchikan Heat Pump Program Building Heat 2 Design Heating No. Ouner Character Floor Area (ft) Load (Btuh) Make Model 1 Hutton 1 story, wood 1482 38,350 Ruud, 4.5 ton, UHQA-16 frame office @10°F Split & UPCA-OSCA space; Retrofit 3 Lewis/Harwell 2 story, wood 1766 -- Sundial, 3 ton, HS 3.0 frame residence Split with flat roof & 1 basement; Retrofit 4 Bambauer/Bone 2 story, wood 1300 -- Coleman, 3 ton, 3236-901 frame residence Split, 15 kW 3240-832 with unheated . backup crawl space; Retrofit 5 Nickles 2 story, wood 1332 32,000 Coleman, 2.75 ton, 3230-901 . frame residence, New @8°F Ambient Split, 10 KW — backup 6 Newell 1 story, wood 3400 -- Whirlpool, 5 ton "A" Coil NESCOS8A0 frame over partially Split in series Cond. NCHAOS8AK heated wood and w/existing oil concrete basement; furnace Retrofit 7 Grainger 1 story, wood 1571 ta Whirlpool, 4 ton NESAO47A0 frame above unheated Split NCHAO47AK partial basement; Furn. HOCO Retrofit BME 070 A47 8 South Coast, Inc. 2 story, wood 4800 44,500 Two (2) G.E. 2ea.048A300B0 frame office @10°F Weathertron, 4 ton Heat Pump building w/insulated Split, 3-phase 2ea.060C400D0 crawl space; New Air Handler 2ca.14.4 KW . Electric Furnace 10 Ketchikan Air 2 story, wood 2400 57,338 Ruud, 5S ton, UHQA-20 Service frame metal upstairs @10°F Split, 20 KW UPCA 057A building, offices upstairs, unheated warchouse downstairs, New 11 Boles 2 story, wood 1900 40,900 Sundial, 3.5 ton, B21-03-15 frame w/cathedral @10°F Split, 15 KW HVC 3.5 ceilings, New HS 3.5 14 Palmer 1 story, ‘ood 2240 45,000 Carrier, 4.0 ton, 38RQ040 frame over partially @10°F in scries w/ 2811Q042021 heated wood § concrete existing basement; Retrofit 15 Ellison 1 story, split level 1930 32,000 Coleman, 4 ton, 3243-901 wood frame residential @10°F Split, 11.5 KW 3112-B above partial unheated garage; New backup otal Installe Capacity Cost 61,000 Btuh @47°F $8,216.00 33,400 Btuh @17°F 35,000 Etuh @47°F 6,150.00 20,000 Btuh @17°F 38,000 Btuh ¢47°F 5,836.00 23,500 Btuh @17°F 35,000 Btuh @47°F 5,691.00 20,500 Btuh @17°F 64,000 Btuh @47°F 5,905.00 38,000 Btuh @17°F 49,000 Btuh @47°F 29,000 Btuh @17°F 6,510.00 -- 12,500.00 61,000 Btuh @47°F 8,185.00 35,400 Btuh 217°F 42,000 Btuh @47°F 5,525.00 24,000 Btuh 917°F 44,000 Btuh €47°F 3,882.60 23,000 Btuh @17°F 47,000 Btuh @47°F 7,409.00 © 28,500 Btuh 17°F ‘TABLE 2 KETCHIKAN HEAT PUMP PROGRAM ELECTRICAL CONSUMPTION (KWII) 1981 1963 —— —————_———_ sep Jocr. 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