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SAVOONGA, ALASKA
HEAT RECOVERY STUDY
PREPARED FOR:
ALASKA NATIVE TRIBAL HEALTH CONSORTIUM
Project ANTHC-09-P52187
PREPARED BY:
Alaska Energy and Engineering, Inc. Mailing Address - P.O. Box 111405 Anchorage, AK 99511-1405
(907) 349-0100, 349-8001 FAX
December 6, 2010
ANTHC-Savoonga Heat Recovery Analysis December 6, 2010
Alaska Energy and Engineering
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EXECUTIVE SUMMARY
The Water Plant in Savoonga was evaluated for heat recovery potential. Total estimated
annual heating fuel is approximately 9,000-gallons. Estimated fuel savings realized by
implementing a heat recovery system is 8,800-gallons. The estimated cost for the heat
recovery project is $299,163. The simple payback based on a fuel cost of $5.00/gallon
is 6.8 years.
1.0 INTRODUCTION
Alaska Energy and Engineering, Inc. was retained by the Alaska Native Tribal Health
Consortium (ANTHC) to review the feasibility of providing available recovered heat from
the existing AVEC power plant to the existing water plant and adjacent community
buildings in Savoonga, and provide a budgetary project cost estimate based on Force
Account Construction, including Design Engineering and Construction Administration.
There is an existing heat recovery system in Savoonga that used to provide recovered
heat to the old Savoonga School. The heat recovery system has been abandoned and
out of service for several years. AVEC constructed a new power plant that went online
in July 2008. The new plant is equipped with a hydronic heating system designed to
provide up to 690 MBh. For purposes of this report, it has been assumed that the
existing hydronic system at the power plant will be modified including adding a heat
exchanger and installing new circulating pumps.
Additional assumptions have been made in the development of this report including but
not limited to the proposed arctic piping route, building heating loads, and flow rates and
pressure drops of the existing power plant cooling system and heat exchanger. It is
anticipated that refinements in arctic pipe size and routing, pump and heat exchanger
sizing, and other design elements will be required as the project progresses to final
design.
Available as-built information was obtained from the Alaska Village Electric Cooperative
(AVEC) regarding the existing generation equipment and power plant heat loads. End-
user annual fuel use was obtained from a variety of sources, including ANTHC and
engineering estimates. No site visits were made to confirm accuracy of
information obtained.
2.0 OVERVIEW
The purpose of this study is to provide an estimate of the heat that can be recovered
from the jacket water of the AVEC power plant diesel engines and used to offset heating
oil consumption at the nearby public buildings. Useable recovered heat is quantified in
gallons of heating fuel saved using a gross heating value of 134,000 BTU per gallon of
#1 arctic diesel fuel and an overall boiler efficiency of 75% for a net heating value of
100,000 BTU per gallon.
The Water Plant is located within a 200-foot radius of the AVEC power plant. This
analysis evaluates the potential to provide recovered heat to the Water Plant (WTP).
The estimated average annual heating fuel consumption for the Water Treatment Plant
is 9,000-gallons.
3.0 ESTIMATED RECOVERED HEAT UTILIZATION
A heat recovery utilization spreadsheet has been developed to estimate the recoverable
heat based on monthly total electric power production, engine heat rates, building
ANTHC-Savoonga Heat Recovery Analysis December 6, 2010
Alaska Energy and Engineering
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heating demand, heating degree days, passive losses for power plant heat and piping,
and arctic piping losses. The spreadsheet utilizes assumed time-of-day variations for
electric power production and heat demand. Power Cost Equalization data for fiscal
year 2009 was used in the spreadsheet. The estimated heat rejection rate for the lead
power plant genset, a Cummins QSX15 G9, is used to estimate available recovered
heat. Heating degree-days for Savoonga were utilized for this site. All arctic piping is
assumed to be routed above grade. All exterior power plant hydronic piping is assumed
to be 3” pipe with 1” of fiberglass insulation and installed above grade. Information
provided by AVEC was used to estimate the heating load for the power plant, which is
comprised of three generation modules, one control module, one housing module, and
three storage modules.
The spreadsheet uses monthly heating degree-days to distribute annual fuel
consumption by month. The monthly heat load is then allocated by hour of day using an
estimated daily temperature variation (diurnal cycle). The end-user hourly heat load is
compared to the hourly available heat from the power plant, less power plant heating
loads and parasitic piping losses, and the net delivered heat to the end-user is
determined.
Following is a summary of annual fuel use and estimated heat utilization in equivalent
gallons of fuel for each building:
Facility Estimated Annual
Fuel Use (Gallons)
Estimated Heat *
Delivered (Gallons)
Water Plant 9000 8800
Total 9000 8800
4.0 HEAT RECOVERY SYSTEM DESCRIPTION AND OPERATION:
The heat recovery system captures jacket water heat generated by the AVEC power
plant that is currently rejected to the atmosphere by the radiators. The recovered heat
will be transferred via arctic piping to the Water Plant. The objective is to reduce the
consumption of expensive heating fuel by utilizing available recovered heat. Although
heat recovery is an excellent method of reducing heating fuel costs, recovered
heat is a supplementary heat source and it is imperative that the end-user facility
heating systems are operational at all times.
Hot engine coolant is piped through a plate heat exchanger located at the power plant.
Heat is transferred from the engine coolant to the recovered heat loop without mixing
the fluids. The recovered heat fluid is pumped through arctic pipe to the end-user
facilities, and is typically tied into the end-user heating system using either a plate heat
exchanger or cabinet unit heater.
AVEC PLANT TIE-IN:
No modifications to the AVEC power plant cooling system are included, except those
required to tie a new heat exchanger into the plant hydronic system, provide circulating
pumps, and install instrumentation.
ANTHC-Savoonga Heat Recovery Analysis December 6, 2010
Alaska Energy and Engineering
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All piping will be insulated with a minimum of 1” insulation and have an aluminum jacket
where exposed to the weather. All valves will be either bronze ball valves, or lug style
butterfly valves with seals compatible with 50/50 glycol/water mixtures at 200F. Air
vents, thermometers, pressure gauges, drain valves and pressure relief valves will also
be provided.
ARCTIC PIPING (Recovered Heat Loop):
Due to permafrost soils in Savoonga, the proposed arctic piping is a pre-insulated
above grade piping system. The piping will be routed from the AVEC plant adjacent to
existing fuel lines and water and sewer piping to the Water Plant.
The arctic piping system is a pre-insulated, bonded steel piping system. The pipes
consist of SCH40 carrier pipe and HDPE outer jacket bonded to polyurethane foam
insulation. The carrier piping joints will be welded. The system comes complete with all
fittings, tools and accessories required for assembly. The recovered heat fluid will be a
50/50 Propylene Glycol/Water solution to provide freeze protection to the piping.
END-USER BUILDING TIE-INS:
End-user building tie-ins typically consist of either brazed plate heat exchangers or
cabinet unit heaters. Plate heat exchangers located in the end-user mechanical rooms
will be tied into the boiler return piping to pre-heat the boiler water prior to entering the
boiler. Where Toyo-style heaters are used, cabinet unit heaters will be located in the
occupied space. The maximum anticipated delivered recovered heat supply
temperature is about 180F. When there is insufficient recovered heat to meet the
building heating load, the building heating system (boiler or heater) will fire and add
heat.
Typical piping will be type L copper tube with solder joints. Isolation valves will be
solder end bronze ball valves or flanged butterfly valves. All piping will be insulated with
a minimum of 1” insulation with an all-service jacket. Flexibility will be provided where
required for thermal expansion and differential movement. Air vents, thermometers,
pressure gauges, drain valves and pressure relief valves will also be provided.
RIGHTS-OF-WAY ISSUES:
There does not appear to be any conflicts with rights-of-ways for the arctic piping
between the power plant and the Water Plant, as the piping will be routed along the
existing water and sewer piping corridor, and on City and AVEC property.
A Heat Sales / Right-of-Entry Agreement will be required between AVEC and the Alaska
Rural Utilities Collaborative (ARUC) to define the parties’ responsibilities, the cost of
recovered heat, and to authorize the renovation of the power plant heat recovery
equipment.
ANTHC-Savoonga Heat Recovery Analysis December 6, 2010
Alaska Energy and Engineering
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5.0 PRELIMINARY EQUIPMENT SELECTIONS
The following initial equipment selections are sized and selected based on preliminary
data and will require minor modifications to reflect final design.
5.1 Heat Exchangers
Based on initial selected flow rates, brazed plate heat exchangers appear to be
adequate for all locations. Initial heat exchanger selections are as follows.
HX-1: (Power Plant). 400 MBH capacity (see note)
Primary: 80 GPM 190F EWT (50% ethylene glycol), 2.0 PSI max WPD
Secondary: 37 GPM 180F LWT (50% propylene glycol) 0.5 PSI max WPD
HX-2: (Water Treatment Plant). 175 MBH capacity.
Primary: 26 GPM 180F EWT (50% propylene glycol), 1.0 PSI max WPD
Secondary: 35 GPM 175F LWT (50% propylene glycol) 1.5 PSI max WPD
Note: the power plant heat exchanger is sized for future system expansion
5.2 Arctic Piping
The length of heat recovery loop piping between the power plant and Water Plant is
approximately 800’-feet, round trip. The arctic piping utilizes 2” SCH40 steel
preinsulated arctic piping to minimize pressure drop and reduce pumping energy. The
piping will be routed above grade alongside existing fuel, and water and sewer piping,
and in a culvert where it crosses beneath the road.
5.3 Circulating Pumps
P-HR1: Heat recovery loop to end-user buildings
Flow = 26 GPM, Head = 24’
Initial Selection: Grundfos UPS 40-80/2F, 26 GPM at 24’ TDH, 3/4 HP
5.4 Expansion Tank
Total heat recovery loop volume is approximately 180-gallons. Pressure relief at the
power plant heat exchanger will be 50 PSIG and the maximum normal operating
pressure will be 90% of maximum (45 PSIG).
ET-1: System requirements: 32.0 gallon tank and 19.7 gallon acceptance
Select: Extrol AX-80V, 44.4 gallon tank and 22.6 gallon acceptance
6.0 CONCLUSIONS AND RECOMMENDATIONS
Estimated construction costs were determined based on prior recent heat recovery
project experience, and include materials, equipment, freight, labor, design, construction
management, and startup and testing. All work at the power plant and water plant, and
design and construction management/administration for the project is included (refer to
attached cost estimate).
The estimated project cost for is $299,163. Estimated fuel savings are about 8,800-
gallons. Using an average fuel price of $5.00/gallon results in estimated savings of
$44,000 for a simple payback of 6.8-years.
12/5/2010 ANTHC HRU-SAV10 .xls Page 1 of 4RECOVERED HEAT UTILIZATION SIMULATION WORK SHEET.Date: December 2010 Location:SavoongaEst. Annual Fuel Savings (Gallons):Fuel heat value:134000Btu/gal(based on #1 arcticdiesel fuel)GENSET DATA - SEE NOTE 3SYSTEM LOSS DATA: Heat rate at kw-load above 1199Btu/kwh Constant losses:Heat rate at kw-load above70 1199Btu/kwh Plant piping:0Btu/hr.Plant piping included in Plant Heating, below Heat rate at kw-load above140 889Btu/kwh Buried Arctic piping:0Btu/hr.Arctic Piping Routed Above Grade, see Exterior Piping, below Heat rate at kw-load above210 855Btu/kwh Genset Eng. Preheat0Btu/hr.see Plant Heating, below Heat rate at kw-load above285 940Btu/kwhTotal constant:0Btu/hr.Heat rate at kw-load above300 940Btu/kwh Heat rate at kw-load above325 940Btu/kwh Variable losses:Heat rate at kw-load above350 940Btu/kwh Exterior piping125Btu/hr.xF800LF 2 steel AP @ 0.14 BTU/Hr-ft-F & 120' Hydronic Pipe @ 0.133 BTU/HR-ft-f Heat rate at kw-load above400 940Btu/kwh Plant heating1000Btu/hr.xF2 Off-Line Generator Mods, 1 Housing Mod, 1 Control Mod & 2 Storage ModsHeat rate at kw-load above450 940Btu/kwh Radiator losses50Btu/hr.xFEstimate for radiator losses Heat rate at kw-load above500 940Btu/kwh GENERATION DATA:WEATHER DATA: PCE Data - See Note 1Kwh/month:HDD/Month: SAVOONGAMonthkWh Gen Fuel UsedJanuary2363141720July13489912540NOTES:February2293391753August155739106981) kWH Generated & Fuel Used Based on PCEFY09Data. March 2277541756September176195115782) Not Used April 2086421454October193179112393) Heat rate of 940 Btu/kWh for Cummins QSX15 G9 genset. May1704091058November22797813030 Heat rate is greater for DD S60 1800 rpm genset, but avail ht based on QSX June174814758December233051 12554July134899559January23631414158August155739560February22933912149Oct thru Apr HDD: 10707September176195712March 22775412571Avg Winter Temp:14October1931791040April 20864213453November2279781226May17040912840December2330511758June17481413738Total: 2,368,313 Total: 14354 Total: 2368313 150548BUILDING DATA:Fuel use,Non-Boilerest'd gal'sgallonsSeasona Seasona Efficiencysaved Building in use, 1=yes, 0=noOper. Oper. JanuaryFebruary March April May June July AugustSeptemberOctoberNovemberDecemberMonths HDDWTP9000 0 75% 8842 1 1 1 1111111111214355Old School 0075%0111 1 10001111912478City Office0075%0111 1 10001111912478Clinic0075%0111 1 111111111214355Police0075%0111 1 10001111912478Misc bldg0075%0111 1 100011119124780075%0111 1 100011119124780075%0111 1 100011119124780075%0111 1 100011119124780075%0111 1 10001111912478Total 9000 0 900088428,842
Heat Avail vs. DemandPage 7Savoonga Estimated Recovered Heat Utilization020040060080010001200140016001800 JanuaryFebruary March April May June July AugustSeptember OctoberNovemberDecemberHeating Fuel Equivalent (Gallons per Month)Recovered Heat AvailableTotal Heat DemandRecovered Heat Delivered
SAVOONGA RECOVERED HEAT020040060080010001200 JanuaryFebruary March April May June July AugustSeptember OctoberNovemberDecemberGallon #1 Heating Fuel8842 Gal Recovered Heat158 Gal Boiler Heat
ALASKA ENERGY & ENGINEERINGANTHC - SAVOONGA HEAT RECOVERY PROJECTCONSTRUCTION COST ESTIMATE SUMMARY 12/5/2010SITE WORK / ARCTIC PIPING $48,020POWER PLANT UPGRADES / EX HEAT RETROFIT $42,200END-USER BUILDING UPGRADES $39,450OVERHEAD $25,538FREIGHT $34,094CONSTRUCTION SUB-TOTAL $189,302DESIGN AND CONSTRUCTION ADMIN. $30,000CONSTRUCTION MANAGEMENT $30,000PROJECT SUB-TOTAL $249,302CONTINGENCY @ 20% $49,860TOTAL PROJECT COST $299,163A-1 of 3
ALASKA ENERGY AND ENGINEERINGANTHC - SAVOONGA HEAT RECOVERY PROJECTFORCE ACCOUNT CONSTRUCTION COST ESTIMATE12/5/2010ITEM QUAN UNIT UNIT MATL UNIT LAB LAB LABOR CONTR FREIGHT TOTAL UNIT TOTALCOST COST HRS HRS RATE COST COST COST COST WT WT(#)SITE & EXTERIOR WORK2" SCH40 Arctic Pipe-PP to WTP800 lin.ft. $41.60 $33,280 0.150 120 $85 $10,200 $43,480 4.36 3487Rigid Insulation (2"x24"x96")0 ea. $17.00 $0 0.10 0 $85 $0 $0 1.00 0Prop Glycol (50/50 - 55-gal drum)6 ea. $450.00 $2,700 0.00 0 $85 $0 $2,700 520 31206x6 Heavy Timber Sleepers160 lin.ft. $3.00 $480 0.10 16 $85 $1,360 $1,840 10 1600Trenching / Grading0 lin.ft. $0.00 $0 0.00 0 $85 $0 $0 $0 0AVEC Power PlantHeat Exchanger (400MBh) 1 ea. $2,000 $2,000 40 40 $85 $3,400 $5,400 100 100Electrical (Misc) 1 ea. $5,000 $5,000 40 40 $85 $3,400 $8,400 500 500Pipe/Valves/Ftgs/Gauges 1 lump $5,000 $5,000 100 100 $85 $8,500 $13,500 1500 1500Circ Pump (Grundfos- 37GPM @ 22' ) 2 ea. $750 $1,500 40 80 $85 $6,800 $8,300 45 90Misc Strut / Pipe Hangers/ Hardware 1 lump $2,000 $2,000 20 20 $85 $1,700 $3,700 500 500Expansion Tank (AX-80V) 1 ea. $1,200 $1,200 20 20 $85 $1,700 $2,900 66 66WATER PLANTPipe/Valves/Ftgs/Gauges 1 lump $5,000 $5,000 60 60 $85 $5,100 $10,100 1000 1000BTU meter 1 ea. $6,500 $6,500 20 20 $85 $1,700 $8,200 50 50Plate HXR, (175 MBh @ 15F)1 ea. $1,200 $1,200 10 10 $85 $850 $2,050 50 50Misc Electrical 1 lump $2,000 $2,000 40 40 $85 $3,400 $5,400 500Misc Strut / Pipe Hangers/ Hardware 1 lump $1,000 $1,000 20 20 $85 $1,700 $2,700 500 500MISCELLANEOUSMisc Hardware 1 lump $5,000 $5,000 0 0 $85 $0 $5,000 500 500Misc Tools & Safety Gear 1 lump $4,000 $4,000 0 0 $85 $0 $4,000 1500 1500Consumables, Gases, Etc. 1 lump $2,000 $2,000 0 0 $85 $0 $2,000 1500 1500OVERHEADROW Legal Work 1 lump $2,000 $2,000 0Rent Heavy Equip 1 lump $2,500 $2,500 0Misc Tool Rent 1 lump $5,000 $5,000 0Commission System & Training 20 hr 1 20 $95 $1,900 $1,900 0Superintendent Overhd Off-Site 40 hr 1 40 $95 $3,800 $3,800 0Superintendent Overhd On-Site 40 hr 1 40 $95 $3,800 $3,800 0Crew Travel Time 10 hr 1 10 $95 $950 $950 0Crew Airfares 2 trips $1,000 $2,000 $2,000 0Crew Per Diem 35 mn.dy. $60 $2,088 $2,088 0Housing Rent 1 mo. $1,500 $1,500 $1,500 0A-2 of 3
ALASKA ENERGY AND ENGINEERINGANTHC - SAVOONGA HEAT RECOVERY PROJECTFORCE ACCOUNT CONSTRUCTION COST ESTIMATE12/5/2010ITEM QUAN UNIT UNIT MATL UNIT LAB LAB LABOR CONTR FREIGHT TOTAL UNIT TOTALCOST COST HRS HRS RATE COST COST COST COST WT WT(#)FREIGHT16,063Freight to Savoonga16063lb. $1.50 $24,094Air Freight Tool Mob & Demob 2 lump $2,500 $5,000Misc Small Freight & Gold Streaks 1 lump $5,000 $5,000CONSTRUCTION SUB-TOTAL $79,860 696 $60,260 $15,088 $34,094 $189,302Engineering (Design & CCA) 1 lump $30,000Construction Management 1 lump $30,000PROJECT SUB-TOTAL $79,860 $60,260 75,088$ $34,094 $249,302Contingency 20 %$49,860CONSTRUCTION TOTAL$299,163A-3 of 3
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