HomeMy WebLinkAboutCity of Seward Heat Pump System Economic Evaluation - Sep 2015 - REF Grant 7091242 TM YourCleanEnergy LLC
308 G Street #215, Anchorage AK 99501 907-274-2007 www.yourcleanenergy.us
ECONOMIC EVALUATION
OF
GROUND SOURCE HEAT PUMP SYSTEM
TO PROVIDE PRIMARY HEAT FOR
CITY LIBRARY & MUSEUM
CITY HALL ANNEX
CITY HALL
FIRE HALL
FOR
CITY OF SEWARD, ALASKA
FINAL REPORT COMPLETED SEPTEMBER 12, 2015 BY ANDY BAKER, PE
TM YourCleanEnergy LLC
TABLE OF CONTENTS
EXECUTIVE SUMMARY STARTER GROUND SOURCE HEATING DISTRICT ALTERNATIVE B .......... ....... 4
SCOPE OF ECONOMIC EVALUATION FOR STARTER GROUND SOURCE HEATING DISTRICT .................. 5
INTRODUCTION ..................................................................................................................................................... 7
EXAMPLES OF SUCCESSFUL OCEAN /GROUND SOURCE HEATING SYSTEMS IN ALASKA ...................... 8
A SUMMARY OF THE FOUR CITY BUILDINGS INCLUDED IN THIS EVALUATION .......................................... 9
RECENT HISTORY OF ELECTRICITY COSTS FOR CITY OF SEWARD BUILDINGS ..................................... 10
RECENT HISTORY OF GRID ELECTRICITY USAGE BY CITY BUILDINGS ..................................................... 11
OPPORTUNITIES FOR INCREASING ENERGY EFFICENCY OF ELECTRICAL LOADS ................................ 12
RECENT HISTORY OF HEATING OIL COST FOR CITY BUILDINGS IN SEWARD .......................................... 13
RECENT HISTORY OF HEATING OIL USAGE BY CITY BUILDINGS ............................................................... 14
RECENT AND PROJECTED HEATING FUEL COSTS FOR THE CITY OF SEWARD ...................................... 15
SUMMARY OF EXISTING BOILERS AND ESTIMATE OF PEAK HOURLY & ANNUAL HEAT LOADS ............ 16
SOLAR HEATING OF THE OCEAN ALONG THE EQUATOR IS MOVED BY GYRES TO ALASKA ................. 17
SEA WATER TEMPERATURE IN RESURRECTION BAY PEAKS EACH YEAR AFTER FALL STORMS ........ 18
GEOLOGY AND SUB-SURFACE WATER RESOURCE BELOW WATER FRONT PARK ................................. 19
CONCEPTUAL DESIGN OF VERTICAL GROUND LOOPS TO EXTRACT OCEAN HEAT ............................... 20
EXAMPLE PROJECT USING DOUBLE U-BEND VERTICAL LOOPS WITH SEPARATOR CLIPS ................... 21
CONCEPT DESIGN OF STARTER GROUND SOURCE DISTRICT HEATING SYSTEM .................................. 22
DRAWING G-1: CONCEPT PLAN OF GSHP PROJECT - ALTERNATIVE A & B .............. .............................. 23
DRAWING G-2: PROJECT SCHEMATIC OF HEATING PUMP SYSTEM ........................................................ 24
TRENCHING OF SUPPLY & RETURN MAINS ALONG AND UNDER CITY STREETS AND ALLEYS ............. 25
INSULATED AND JACKECTED HDPE SUPPLY AND RETURN GROUND SOURCE MAINS .......................... 26
GROUND SOURCE HEAT PUMP OPERATION AND COEFFICIENT OF PERFORMANCE (COP) ................. 27
SELECTION OF WATER SOURCE HEAT PUMPS SUITABLE FOR USE IN CITY BUILDINGS ....................... 28
SUMMARY OF OPERATION & MAINTENANCE COSTS FOR STARTER DISTRICT HEAT SYSTEM ............. 29
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 3 OF 38
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TABLE OF CONTENTS (Continued)
COST OPINION - ALT B: GROUND SOURCE DISTRICT HEAT FOR ALL FOUR CITY BUILDINGS .............. 31
COST OPINION - ALT B: GROUND SOURCE DISTRICT HEAT FOR ALL FOUR CITY BUILDINGS
(CONTINUED) ....................................................................................................................................................... 32
APPENDIX A: ANNEX BUILDING - OIL BOILER - FUEL USE VS. OUTSIDE TEMP - DATA LOGGER .......... 33
APPENDIX B: FIRE HALL - OIL BOILER - FUEL USE VS. OUTSIDE TEMP - DATA LOGGER ....................... 34
APPENDIX C: CITY HALL - OIL BOILER - FUEL USE VS. OUTSIDE TEMP - DATA LOGGER ....................... 35
APPENDIX D: QUOTE TO DRILL AND INSTALL 2 TEST HOLES & 10 VERT GROUND LOOPS ................... 36
APPENDIX E: QUOTE FOR INSULATED HDPE PIPE WITH JACKET- SUPPLY & RETURN MAINS ............. 37
APPENDIX F: QUOTE FOR HEAT PUMPS, LOOP PUMPS, BUFFER TANKS, U-BEND COILS ..................... 38
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 4 OF 38
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EXECUTIVE SUMMARY STARTER GROUND SOURCE HEATING DISTRICT ALTERNATIVES
50 Year Present Worth Financial Analysis Of Starter Heating District Alternative B:
Alternative B:
All Four City Bldgs
17 Boreholes
Description Of Financial Component 8 Heat Pumps
Total Installed Project Cost Opinion -$850,000
Electricity use by source pumps - Year 1 -$2,290
Present worth of electricity use by
source pumps - over 50 year project life* -$114,500
Electricty use by heat pumps - Year 1 -$37,208
Present Worth of electricity use by
heat pumps - over 50 year project life* -$1,860,400
Maintenance Cost - District Heat System - Year 1 -$1,200
Present Worth of Maintenance Cost For
District Heat System - over 50 year project life** -$185,800
#1 Heating Oil Saved By Heat Pumps - Year 1 $60,462
Present Worth of #1 Heating Oil Saved By
Heat Pumps - Over 50 year project life*** $4,466,637
Net Present Worth Of Project Over 50 Years $1,455,937
Net Annual Savings At End Of Year 1 $19,764
Benefit To Cost Ratio 1.48
Notes:
* Grid electricity at industrial user rate from City of Seward, with 3% per year escalation
** Maintenance labor costs escalating at 3% per year
*** Unit cost of #1 heating oil escalating at 4.5% per year
- Discount rate applied to all financial components is 3% per year
- Current Large General Service rate for City of Seward grid electricity is $.184/KWH
- Cost of #1 heating oil is estimated to be $3.02/gallon at start of project
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 5 OF 38
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SCOPE OF ECONOMIC EVALUATION FOR STARTER GROUND SOURCE HEATING DISTRICT
1. Provide background of and scope for the Economic Evaluation, and overall goals of the City to
establish a starter heating district using a vertical ground source loop field near the ocean, and
heat pumps in the City Library and Annex that are supplied from trunk lines connected to the
ground loops.
2. Evaluate the historical cost of heating in downtown Seward using heating oil, and straight electric
heat for the past ten years. Based on the latest price projections and information from both
heating oil suppliers and City Electric Department, estimate anticipated escalation of heating oil
and grid electricity prices in downtown Seward for the next 30 years. Estimate inflation and
discount rates anticipated over the same time period.
3. Provide several examples from Southcentral and Southeast Alaska of similar ground or ocean
source heating system that have displaced oil or electric heat through the winter heating season
for at least two years. Describe the size of these systems, # of customers, and annual heating
loads served. For the purpose of comparison to City of Seward, indicate the method of delivered
heat price determination and the actual savings realized over other conventional fuels that are
displaced by this system.
4. Develop a conceptual design schematic of a starter district heat system to initially serve the
Library and Annex buildings. This concept would include a vertical borehole ground source loop
field on City property adjacent to Resurrection Bay, a supply and return trunk line along Adams
Street, variable speed drive district loop pumps in the Library basement, and water source heat
pumps to replace boilers currently located in the basement of both the Library and Annex. A
conceptual design schematic illustrating the conversion of medium temperature heat distribution
appliances within each of these buildings will also be included. The conceptual design schematic
will consider expansion of the starter district in the future to provide source heat for the City Hall
and Fire Hall.
5. Develop conceptual design for a field of vertical geothermal boreholes on City shoreline property
at the base of Adams Street. Discuss anticipated subsurface soil conditions, thermal
conductivity, depth to bedrock, ground water levels, influence of ocean tides, salinity, borehole
depth and spacing, manifold arrangement. Identify adjacent areas where the borehole field may
be expanded in future to serve additional buildings via the trunks proposed along Adams Street
for the Library and Annex. Recommend a scope of work for a driller to install several test
boreholes to confirm subsurface conditions in the area of the proposed borehole field.
6. Develop concept level typical sections for the anticipated trenching of district loop supply and
return trunk lines along and under city streets, sidewalks and frontage. Identify an appropriate
type of pipe material, depth of bury, insulation requirements, shut off valves, and other details that
will have cost implications for the buried piping included in the district system. Determine whether
branch supply and return lines may be placed in the same trench with new water lines or other
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 6 OF 38
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buried utilities already scheduled for replacement by the City. Discuss optimal depth for buried
trunk lines.
7. Based on actual heating fuel usage for the past four years, and installed boiler sizes, estimate
annual heat load and peak hourly heat demand rates for the Library, Annex, City Hall, and
Firehall. This work item will require that the City install, within two weeks of Notice To Proceed
for this evaluation, a fuel meter (total gallons consumed) on each operating oil boiler, and a KWH
meter on the electric boiler in the Library. Heat load estimates can then be calibrated against
actual fuel usage recorded over the winter of 2014/15.
8. For the Library and Annex buildings, an inventory of the existing heating appliances, heat loads
and hydronic supply temperatures shall be made, based on the Design/As-Built mechanical and
electrical drawings for this building. A strategy will be developed for the conversion of medium
temperature (140F to 180F) heating loads to low temperature (100F to 130F), assuming
replacement of the oil boiler and/or electric boiler with heat pumps of similar capacity.
9. For the Library and Annex buildings, estimate if a net increase in electrical power service will be
required for the building in order to integrate heat pumps. Discuss whether a need for standby
power exists for either building.
10. For the initial Library and Annex ground source heating district, develop an opinion of probable
cost for design and construction, expressed in 2015 dollars.
11. For the initial Library and Annex ground source heating district, estimate the anticipated annual
Operation and Maintenance costs, including electricity usage, operational staff, parts,
maintenance, technical support, etc.
12. For the initial Library and Annex ground source heating district, estimate the annual savings in
2015 dollars anticipated from the ground source district heat system over continued use of the
existing oil and electric boilers.
13. For the initial Library and Annex ground source heating district, develop an itemized opinion of
probable cost for design and construction. Develop a Net Present Worth analysis with 30 year
life cycle, using the current energy costs and projected escalation rates, discount rate, and
inflation rate appropriate for this type of City-owned infrastructure project. This analysis will
indicate years to payback investment of ground source district heat versus the base case of
continuing with existing heating oil and electric boilers/resistance heat.
14. Estimate the portion of the design and construction costs that could likely be funded by federal
and/or state renewable energy grant programs currently available to the City.
15. Produce deliverable Economic Evaluation report in PDF format that includes above items,
schematics, graphs, technical information, cost estimates, etc, in a simple easy to read format.
16. Make one public presentation in Seward to communicate the results of the evaluation.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 7 OF 38
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INTRODUCTION
On December 12, 2014, the City of Seward secured the services of YourCleanEnergy (YCE) to prepare
an Economic Evaluation of Starter Heating District to serve the City Library and Annex buildings in
downtown Seward (described here in as "ALT A"). The evaluation also considers an expanded system
that includes City Hall and the Fire Hall in the starter heating district (described here in as "ALT B").
The Annex is currently heated with an oil fired boiler; the Library is heated with an oil fired boiler and an
electric boiler. The City Hall and Fire Hall both have two oil fired boilers in them. The concept of this
evaluation is based on converting the primary source of heat from existing heating oil and electric boiler
heat systems to ground source heat pump systems. The ground source loops would derive source heat
from a closed loop vertical borehole field located in the City owned park adjacent to Resurrection Bay.
BACKGROUND
Significant operational savings are anticipated over time by replacing heating oil boilers in select City
buildings with ground or ocean source heat pumps. The anticipated savings are based on results of other
ground source and ocean source heat pump systems in the Seward area that are operating at about half
the cost of oil or straight electric heat systems. The City owns Waterfront Park along Resurrection Bay
that is currently used for recreation and camping; these areas lie above water saturated deep alluvial
deposits that have strong potential for cost effective and low impact installation of vertical ground loops
fields. These fields can supply a district loop to serve heat pumps installed in City Buildings. Vertical
ground loops, up to 300 foot depth, installed in ocean frontage areas may be warmed by the ground and
ocean heat from the Bay, without the challenges of directly pumping sea water. Initial starter heating
district loops can be designed with capacity for expansion to serve more nearby heat loads in the future.
There are four City buildings downtown in close proximity to the Bay frontage property, and to each other,
that have potential for conversion to heat pumps: the City Library, City Annex, City Hall and the Fire
Station. Of these buildings, the City Library is the most appropriate for conversion to heat pumps due to
its new construction with well insulated envelope, radiant floors, and modern hydronic system. The
Annex is adjacent to the Library and has had recent envelope improvements that are likely to make a
conversion of this building to a heat pump system cost effective. The City Hall and Fire Hall are older
multi-use buildings that would benefit significantly from both a comprehensive energy audit and
fundamental energy efficiency improvements. However they are also good candidates even in their
present condition for receiving district heat. As more energy efficiency improvements are made over time
to the City Hall and Fire Hall, the heat production required from heat pumps will reduce. This will in turn
free up heat capacity for other potential buildings or customers. Energy audit services for City Hall and
the Fire Hall were not included in the scope of this district heating system evaluation.
The evaluation herein will consider a starter heating district that initially serves the City Library and Annex
buildings (Alternative A), with planned capacity and connections for City Hall and the Fire Hall (Alternative
B). Economic, technical, and operational success with these first two buildings may then demonstrate the
potential benefits of expanding the district loop to other City buildings. Due to economy of scale, there
may be an advantage to constructing a district heat system to serve all four buildings from the start
(Alternative B). At the present time there are multiple sources of state and federal grant funds that the
City may apply for to finance such a project. The Economic Evaluation proposed herein can be leveraged
as the basis for grant funding and/or appropriation to finance the design and construction for the initial
starter district. The Alaska Energy Authority Renewable Energy Fund receives grant applications in
September of each year for projects that may be funded in the following fiscal year.
Acknowledgements. YCE would like to thank City Council for taking steps towards a district energy plan
that taps the immense and natural heat resource that is Resurrection Bay. Thanks is also expressed to
Ron Long, Jim Hunt and Susie Towsley for City contract administration; Stefan Nilsson for coordinating
access to City personnel, buildings & drawings; Valarie Kingsland for Library tours; WC Casey for advice
on utilities; John Foutz for advice on electric rates; Steve Audette for testing boilers; Dwayne Atwood for
providing planning maps; Phil Kaluza for sage advice, data loggers and annual fuel use analysis.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 8 OF 38
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EXAMPLES OF SUCCESSFUL OCEAN /GROUND SOURCE HEATING SYSTEMS IN ALASKA
Alaska SeaLife Center, Seward. In 2009, an Economic Evaluation comparing the installation and use of
sea water heat pumps to replace existing oil boilers was completed by YourCleanEnergy. In 2010, the
120,000 square foot Alaska SeaLife Center received grant funds from the Denali Commission and Alaska
Energy Authority to design and install two 90 ton heat pumps that utilize sea water from ice free
Resurrection Bay to provide heat for indoor spaces, outdoor sidewalks, and domestic hot water. In
December 2012, the two existing oil boilers were turned off and the sea water heat pump system
performance was monitored continuously through December 2013. Throughout 2013, the heat pump
system displaced 48,104 gallons of heating oil, producing a net savings of $120,000 and a net CO2
emission reduction of 420,000 lbs. The average system COP (coefficient of performance) for the year was
2.77; this represents an efficiency of 277% over heating oil or straight electric heat. In 2014, AEA
provided an Emerging Energy Technology grant to design and install additional heat pumps that utilize
CO2 as refrigerant and lift from sea water temperatures (40 degrees F) up to 194 degrees F for
baseboard heat in the offices and labs. This project is currently under design by YourCleanEnergy.
International Airport, Juneau. This project was placed on line in May 2011. The use of ground source
heat at the Juneau International Airport Terminal is part of an overall renovation and expansion project.
The Airport was constructed on filled wetlands that receive sub-surface influence of ocean tides and fresh
water drainage. Based on a feasibility study, a Ground Source Heat Pump (GSHP) scheme offered a
financial incentive to move away from traditional fuel oil-based heating systems to one that extracts heat
from the ground and obtains most of its purchased energy from cleaner hydroelectric sources. The
system is comprised of a closed ground loop with 108 vertical borings, each 360 ft. deep; 6 miles of
HDPE pipe in the field; 26 water to air heat pumps(Climate Master); 3 water to water heat pumps
(McQuay); and one Climate Master Direct Outside Air Supply (DOAS) unit. The loop field has
dimensions of 110 ft. x 275 ft and is located under the commuter/charter aircraft tie-down area.
Implementing this new system is affording annual savings in heating oil to the City of 35,000 gallons
worth @$115,000 along with $10,000 a year in staff labor and $1,000 in snow removal equipment.
Seldovia House Ground Source Heat Pump System. A new heat pump system for this 17,000 sq ft
senior and low income housing complex was placed on-line in December of 2014. Evaluation of
replacing oil boilers with ten x 300 ft deep vertical ground loops (in solid basalt) and two heat pumps was
completed by YCE in 2013. Grant funding from Alaska Energy Authority under the REF Round 7 allowed
for design to be completed by YCE in August 2014; construction was completed by November 2014. For
winter of 2014/2015, the heat pumps displaced approximately 80% of the heating oil normally used.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 9 OF 38
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A SUMMARY OF THE FOUR CITY BUILDINGS INCLUDED IN THIS EVALUATION
A summary of basic information regarding the four city buildings included in this evaluation is given below:
Building Name Sq Ft Date Built Type Of Use
Fire Hall 7,262 1963 Emergency Response, Bldg Inspector
City Annex 8,192 1950 Elect Dept, Planning Offices
City Hall 20,532 1966 City Admin, State & Federal Offices
Library/Museum 24,323 2012 Public Library & Historical Museum
Building Name # of Boilers Boiler Type Liquid Fuel Type Fuel Tank Size
Fire Hall Two Oil Fired #1 Heating Oil 2000 Gallons*
City Annex One Oil Fired #1 Heating Oil 500 Gallons
City Hall Two Oil Fired #1 Heating Oil 2000 Gallons*
Library/Museum Two (Oil Fired + Electric) #1 Heating Oil 2000 Gallons
*Fire Hall and City Hall share a single tank located adjacent to the Fire Hall
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 10 OF 38
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RECENT HISTORY OF ELECTRICITY COSTS FOR CITY OF SEWARD BUILDINGS
Buildings owned and operated by the City of Seward are currently charged by the Seward Electric Utility
at either the Small General Service or Large General Service rate. Seward Electric Utility purchases firm
power from Chugach Electric Association (CEA) with the exception of local diesel generation when
Chugach power is interrupted by avalanches or other events. The Small General Service and Large
General Service electric rates consist of the following price components:
Primary Charge ($/KWH) + Additional Charge ($/KWH) + Peak Demand Charge ($/KW) + CEA Fuel
Charge ($/KWH) + Monthly Charge ($/Month) = Total Monthly Charge
For simplicity, an Effective Electricity Rate ($/KWH) is used in this evaluation report to estimate future
costs for loop pumps and heat pumps. The Effective Electricity Rate ($/KWH) is express as the Total
Monthly Charge ($) divided by Total Monthly Energy (KWH) used. There can be some significant
variation in the Effective Electricity Rate between buildings at times when one building has low
occupancy, or when an electric heating appliance is imposing a high demand charge on the meter
account. This is seen below for the Annex during a times it was unoccupied in 2013, and for the Library
when the electric boiler was used instead of the oil fired boiler in 2013 and 2014.
The Small General Service rate is the highest of all tariff rates applied to City buildings and has a current
effective rate of $0.205/KWH. The Large General Service currently has an effective rate of $0.184/KWH.
The proposed Ground Source Heat Pump Project will house all heat pumps and loop pumps in
either the Library or City Hall; only the Large General Service rate will apply to the project.
The future price escalations in electricity cost in Seward are closely tied to those of Chugach Electric
Association. The unit price of grid electricity from Chugach Electric Association has risen at a rate of
approximately 3% per year for the past four years. This increase has been tempered by the fact that 15%
hydro-electric which has stabilized the retail cost of electricity; and load
sharing between utilities on the rail belt grid of Alaska has prevented any one utility from subjecting
customers to rapid price escalations. The primary factor expected to determine the escalation rate of
ity is the cost of natural gas generation. This cost can vary due to regional Henry
Hub pricing and available supply in the region for this commodity. Another factor that may influence the
wholesale price of power from CEA in coming years is the size of their customer base in relation to their
generating capacity. An increase in the purchase of wind generation may help stabilize pricing.
The economic evaluations contained in this report are based on the rate of grid electricity from
City of Seward escalating at an average rate of 3% per year for the next 30 years. The addition of
local hydro electric power to the Seward City grid could further stabilize the retail price by reducing
dependence on natural gas generation by Chugach Electric and by providing some alternative to
emergency diesel generation during those times when supply from Chugach is interrupted.
$0.1400
$0.1900
$0.2400
$0.2900
$0.3400 $ / KWH EffecƟve Electricity Rate For City Buildings - 2010 thru 2014
Annex (Small General
Service)
Fire Hall (Small General
Service)
City Hall A (Large General
Service)
City Hall B (Large General
Service)
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 11 OF 38
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RECENT HISTORY OF GRID ELECTRICITY USAGE BY CITY BUILDINGS
The amount of City budget spent on electricity for City Buildings has been significant for the previous four
heating seasons. For the heating season of 2013/2014 the total cost of electricity used by all four city
buildings was $162,329. This high amount of electricity usage is attributed in part to high levels of
occupancy (lighting, office equipment, computer servers, communication equipment, ventilation); and to
the use of electric resistance type space heaters in the older buildings, City Hall in particular.
Average annual electricity usage in KWH by City buildings over the past four heating seasons (July 2010
thru June 2014) are shown below.
In terms of average annual electricity usage, the City Hall has been by far the largest. This is due in part
to the high occupancy and multi-use features of the building. It is self evident that some amount of electric
resistance space heating is occurring in the winter months in this building to compensate for the poor
insulation value of the walls, windows, and roof. The Library/Museum is a relatively new facility however it
was noted during site visits to this building that efficiency improvements can be made in both lighting and
HVAC controls. One specific example is replacing the incandescent spots in the Museum exhibit hall with
LED lamps. Another is recovering some of the solar heat gain from the second floor reading rooms that
is currently wasted by opening clear story windows when the rooms over heat on sunny days. A
comprehensive energy audit of all four City buildings would very useful to increase their efficiency.
Fire Hall Annex City Hall Library
2010/11 $12,202 $8,971 $46,341
2011/12 $12,261 $10,085 $49,877
2012/13 $12,606 $6,391 $48,332 $52,061
2013/14 $13,927 $6,246 $48,238 $45,679
$0
$10,000
$20,000
$30,000
$40,000
$50,000
Annual Electricity Expense (July 2010 thru June 2014)
Fire Hall Annex City Hall Library
KWH 65,360 40,114 282,024 197,660
0
50,000
100,000
150,000
200,000
250,000 KWHAnnual Electricity Usage (4 Yr Avg - July 2010 thru June 2014)
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 12 OF 38
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OPPORTUNITIES FOR INCREASING ENERGY EFFICENCY OF ELECTRICAL LOADS
It is useful to review the relative size of the four city buildings when evaluating the amount of energy used
by those buildings:
It is useful to compare the intensity of electricity use among City buildings because this will indicate
whether large differences in lighting, appliances, and/or electric space heating loads are occurring
between the buildings. This intensity can be expressed as KWH / square foot building area / year:
As shown below, City Hall has by far the highest level of electricity use per square foot. It is
recommended that a comprehensive energy audit of the Fire Hall and City Hall be performed to
determine what cost effective improvements in lighting, HVAC pumps/ventilation, and electrical
appliances, can be made to reduce electrical energy usage. Sub-metering of major electric loads can
help to identify the largest categories of power usage. It appears that a large number of individual electric
space heater may be in use to supplement building heat on cold and windy winter days. Increasing
envelope insulation and retro-commissioning of the heating and ventilation system of the buildings can
eliminate the need for supplemental space heaters and afford large energy savings.
Fire Hall Annex City Hall Library
Sq Ft 7,262 8,192 20,532 24,323
0
5,000
10,000
15,000
20,000
25,000 Square Feet of Floor Area Usable Interior Floor Area Of City Buildings
Fire Hall Annex City Hall Library
KWH/Yr/Sq Ft 9.00 4.90 13.74 8.13
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00 KWH / Year / sq ft bldg area Electricity Use / Year / Sq Ft Bldg Floor Area (4 Yr Avg)
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 13 OF 38
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RECENT HISTORY OF HEATING OIL COST FOR CITY BUILDINGS IN SEWARD
In order to plan for energy efficiency and district heat projects for buildings in Seward, it is useful to review
the trend of heating oil cost ($/gallon delivered) from the past ten heating seasons (July 2004 thru June
2014). The City of Seward purchases #1 heating oil from Shoreside Petroleum for their buildings.
Over the past four years, the price of heating oil in Seward has varied greatly, as can be seen in the
graph above of heating oil bill fuel prices from 2010 to 2014. A large price spike occurred in May 2011,
with prices hitting over $3.90/gal. Following the 2011 spike, prices remained in the range of $3.60/gal
through August of 2014. A surplus of oil supply in the global market starting in September of 2014 has
driven prices down temporarily to the range of $3.20/gal. It is anticipated that global supply will reduce in
the near future, and the market price for heating oil in Seward will return to the range of $3.90/gal.
The total amount of City budget spent on heating oil for the four city buildings reached $67,605 for the
2012/2013 heating season due to a cold winter and moderately high oil prices. While it is not the largest
of the four buildings, City Hall consumes the greatest amount of heating oil by a noticeable margin. City
Hall is an older structure that can benefit from a comprehensive energy audit and various energy
efficiency improvements that include increased wall and roof insulation, new thermally broken thermo-
pane windows, retro-commissioning of existing HVAC system, and clearing the air path to baseboards.
$2.50
$2.70
$2.90
$3.10
$3.30
$3.50
$3.70
$3.90
$4.10 Aug 9 2010Oct 19 2010 Dec 13 2010 Feb 3 2011 Apr 7 2011 Jun 2 2011 Aug 11 2011 Oct 11 2011Jan 5 2012 Feb 15 2012 Apr 19 2012 Jul 16 2012 Oct 20 2012 Dec 21 2012 Jan 15 2013 mar 6 2013 may 23 2013 sep 13 2013 nov 22 2013 Jan 23 2014 Mar 28 2014 May 13 2014 Sep 10 2014 Nov 18 2014Price Per Gallon Delivered Recent Price Of #1 HeaƟng Oil For City Of Seward Buildings
Fire Hall Annex City Hall Library
2010/2011 $8,973 $6,347 $20,937 $0.00
2011/2012 $11,563 $7,940 $26,979 $0.00
2012/2013 $11,318 $8,322 $26,408 $21,557.51
2013/2014 $9,723 $7,133 $22,688 $17,487.00
$0 $5,000 $10,000 $15,000 $20,000 $25,000 $30,000
Annual HeaƟng Oil Cost - City Buildings - 2010 thru 2014
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 14 OF 38
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RECENT HISTORY OF HEATING OIL USAGE BY CITY BUILDINGS
The overall efficiency of heating oil usage in the four City buildings can be compared to each other by
dividing the total amount of heating oil used each year in the building by the total usable floor area. While
the Fire Hall is the smallest of the buildings, it has consumed the greatest amount of heating oil per unit
floor area. This is attributed in part to the regular opening of large overhead doors for vehicles throughout
winter days; and also to poor insulation in portions of the building envelope, in particular the roof.
Fire Hall Annex City Hall Library
Sq Ft 7,262 8,192 20,532 24,323
0
5,000
10,000
15,000
20,000
25,000 Square Feet of Floor Area Usable Interior Floor Area Of City Buildings
Fire Hall Annex City Hall Library
Gallons 3,325 2,475 7,480 6,064
0
2,000
4,000
6,000
8,000 Gallons of #1 Heating Oil Annual HeaƟng Oil Usage (4 Yr Avg - July 2010 thru June
2014)
Fire Hall Annex City Hall Library
BTU/Yr/Sq Ft 45,624 27,434 33,408 26,149
0
10,000
20,000
30,000
40,000 BTU / year / sq ft BTU / Year / Sq Ft Area (4 Yr Avg - July 2010 thru June 2014)
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 15 OF 38
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RECENT AND PROJECTED HEATING FUEL COSTS FOR THE CITY OF SEWARD
For the past twenty years or more, the City of Seward has utilized heating oil as the primary fuel source
for space heating boilers and back power generation. In recent years, the City has purchased large
quantities of #1 heating oil at bulk rate from Shoreside Petroleum. The actual price paid per gallon for
recent years is shown below. While there have been fluctuations in the unit cost of crude oil products in
the past four years, the overall price escalation has been on a baseline of 6% per year from August 2010
($2.80/gallon) through December 2014 ($3.60/gallon).
The recent surplus of crude in the global market has driven down heating oil price since September of
2014, however this is likely a short term effect. Healthy economic growth in the USA is expected in
coming years, along with some reduction in crude oil demand in the USA due to efficiency increase. The
long term global shortage of crude oil supplies and growing global demand, especially that of China and
India, may increase the escalation rate. The use of a 4.5% per year escalation for heating oil in Seward is
both conservative and realistic given the past and projected history of crude oil prices.
An electric boiler was installed in the new Library/Museum as an alternate heating method to burning
heating oil. The electric boiler has not been used often due the fact that the recent price of oil has made
operation of the two stage (low and high fire) oil boiler far more cost effective.
At current retail electricity and fuel oil rates (Dec 2014), using ground source heat pumps with
electricity priced at the Large General Service (LGS) rate will be approximately 1.6 times more
cost effective than heating with oil boilers.
Using ground heat pumps with electricity priced at the Large General Service (LGS) rate will be
approximately 2.5 times more cost effective than using an electric boiler.
Cost of making 1,000,000 BTU with #1 heating oil (using 85% eff boiler, $3.90/gal) = $34.24
Cost of making 1,000,000 BTU with electric heat (@ LGS Rate of $0.182/KWH) = $53.33
Cost of making 1,000,000 BTU with heat pump system (COP 2.8, $0.182/KWH) = $19.05
$2.50
$2.70
$2.90
$3.10
$3.30
$3.50
$3.70
$3.90
$4.10 Aug 9 2010 Oct 12 2010 Nov 9 2010 Jan 5 2011Feb 3 2011 Mar 29 2011 May 13 2011 Jun 23 2011 Aug 11 2011 Sep 21 2011 Nov 22 2011 Jan 12 2012 Feb 15 2012 Apr 9 2012 Jun 1 2012 Aug 24 2012 Oct 20 2012Dec 13 2012jan 8 2013 jan 31 2013 mar 6 2013 apr 25 2013 jul 18 2013 oct 3 2013 nov 22 2013 Jan 9 2014 Feb 11 2014 Apr 3 2014 May 13 2014 Jul 15 2014 Oct 23 2014Dec 1 2014 Price Per Gallon Delivered Recent Price Of #1 HeaƟng Oil For City Of Seward Buildings + 6%/Yr EscalaƟon Line
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 16 OF 38
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SUMMARY OF EXISTING BOILERS AND ESTIMATE OF PEAK HOURLY & ANNUAL HEAT LOADS
In January 2015, the City of Seward performed field testing of the existing oil fired boilers in City Hall,
Annex and the Fire Hall. While the boilers were running hot, an analysis of combustion flue gas
temperature and composition was performed. Additionally, run time data loggers were installed on these
oil boilers for the entire month to determine how often the boilers were running on the coldest days. From
these field measurements and equipment data, the peak hourly heat load (Btu/hour) of the buildings was
estimated for the design winter outside air temperature of 5F. It was then possible to estimate the size of
new hi-efficiency water source heat pumps that could effectively replace the heating capacity of the
existing boilers:
Data from the run time loggers was used to create heat load graphs for each building that are based the
typical winter outside air temperatures measured in recent years in Seward. These graphs are shown in
the Appendix of this report. From the simulation software associated with the data loggers, the design
annual heat load and heating oil usage was estimated. These design heat loads are then used in the
economic evaluation to establish how much heating oil will be displaced by heat pumps, how much
electrical energy is required for loop pumps and heat pumps, and what annual savings that will produce.
Site Library /
Museum
Library /
Museum City Hall City Hall Fire Hall Fire Hall Annex Bldg.
Burnham Lattner
Electric
System
2000
Weil
McLain
System
2000
System
2000
Weil McLain
V904A S135LW EK-3F V600 EK-1 EK-1 P-768-WT
Lead boiler Lag boiler Lead boiler Lag boiler #1 #2
Stack Temp.370* 360* 440* 400* 350* 480*
CO2 11.60% 3.20% 2.20% 8.20% 7.70% 7.50%
CO 37 ppm 18 ppm 84 ppm 0.0 ppm 0.0 ppm 17 ppm
2 4.90% 16.50% 19.20% 9.60% 9.50% 10.60%
Extra Air 28.20% 34.50% 51.90% 78.30% 53.80% 93.10%
2.1 low fire
4.3 high fire
Nozzle 2.1 2.6 1 N/A
Flow Rate gal/hour gal/hour
Gross Output 281,400 460,000 348,400 134,000 248,000
BTU/Hour on low fire
Field Measured 86.20%
Efficiency on low fire
Net BTU/Hour 242,567 No Data 255,029 110,550 194,928
Run Time @5F 95.00% No Data 95.00% 90.00% 45.00%
Peak Hourly Heat
Load @5F BTU/Hour 230,438 No Data 242,277 99,495 87,718
Heat Pump Cap
(Tons) Req'd To
Offset Boilers
19 21 9 8
Design Annual Heat
Load (MMBTU)700 734 368 261
Design Annual Oil
Usage (Gallons)6,064 7,480 3,325 2,475
Site Library /
Museum
Library /
Museum City Hall City Hall Fire Hall Fire Hall Annex Bldg.
Boiler
Nozzle 2.00-60A 250-60A .75-70A 1.25-60A
No Data 73.20% 68.20% 82.50% 85.00% 78.60%
.75-70A
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 17 OF 38
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SOLAR HEATING OF THE OCEAN ALONG THE EQUATOR IS MOVED BY GYRES TO ALASKA
The natural delivery of warm sea water to Resurrection Bay is part of the global heat engine. Large
amounts of solar energy are absorbed by the ocean and atmosphere and are transported poleward. A
simple example is that winds and currents from the south are generally warmer than those from the north.
In the North Atlantic Ocean, the Gulf Stream carries warm water from the tropics to high latitudes along
the East Coast of the U.S. It then moves across the North Atlantic and warms Europe. This clockwise
gyre or circular pattern fills the North Atlantic.
The North Pacific is also warmed by a similar ocean circulation with the Kuroshio Current bringing water
from the tropics northward along Japan and then eastward across the North Pacific. This current hits
North America offshore of Seattle where it splits into the southward flowing California Current and the
northward flowing Alaska Current. The Alaska Current brings warm water into the Gulf of Alaska.
warm, salty tropical water. This lid overlies the subsurface source of warm water in the Alaska Current.
The Alaska Current flows around the Gulf of Alaska in a counterclockwise direction along the shelf break
which is about 100 miles offshore near Seward.
As the rains increase in autumn, a lot of freshwater enters the ocean from the coast. As it piles up along
the coast, it begins to move offshore. The water beneath this upper layer of freshwater is mixed a little
and is also carried offshore. It is replaced with water from below. This upper layer offshore moving layer
allows deeper water to move to the coast. This deep layer of warm water supplies the heat from the
tropics that warms Resurrection Bay each fall. This same heat has been successfully tapped to heat the
Alaska SeaLife Center through long sub-arctic winters since 2011 using high efficiency heat pumps.
The Seward Line is a line of reference to obtain the oceanographic properties across the shelf and into
the deep Gulf of Alaska. The GAK1 monitoring station and Seward Line was established in December
1970. 17 years ago it was expanded to include biology and it continues to be sampled.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 18 OF 38
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SEA WATER TEMPERATURE IN RESURRECTION BAY PEAKS EACH YEAR AFTER FALL STORMS
It has long been known that sea water temperatures in Resurrection Bay remain well above freezing
through the long Alaska winter. The Bay stays ice free and is often steaming on cold days in early winter.
This is due primarily to a large influx of warm sea water from the Alaska Coastal Current that is drawn into
the bay each fall due to high volumes of fresh water storm runoff. The Alaska Coastal Current is in turn
heated by the North Pacific Gyre that gains immense solar heat during its three year journey along the
equator. Resurrection Bay is a world class source to operate a district heating system from.
Seawater temperatures recorded for a recent five year period (2003 through 2008) at the Alaska SeaLife
each month. The maximum monthly seawater temperature (56F) and minimum monthly seawater
temperature (37F) were also identified. As shown in the graph below, it is evident that the large mass of
seawater contained in Resurrection Bay is slightly charged by local solar during the spring and summer
months, and is heavily charged by warm ocean currents in advance of the winter heating season.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 19 OF 38
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GEOLOGY AND SUB-SURFACE WATER RESOURCE BELOW WATER FRONT PARK
The existing geology and subsurface water resources of Waterfront Park in Downtown Seward show
great promise as a utility grade heat source for ground source heat pumps. Most of the high density area
of Seward rests upon an alluvial fan of gravel and silt deposits that have washed down from the Lowell
Creek Canyon for thousands of years. Due to the steep sloping bedrock under the town site, the
thickness of alluvial gravel along the shoreline is in excess of 300 feet thick. This thick layer of gravel is
water saturated due to the presence of fresh water drainage from higher elevations, and seawater
infiltration from the adjacent Resurrection Bay. The sea water heat is of great interest for this project.
In 1967, in response to the Good Friday Earthquake of 1964, the United States Geological Survey
(USGS) compiled a report of the existing geology of Seward, with attention to the fracture zone that is
parallel to the shoreline. Much of the infrastructure built along the shoreline prior to the 1964 earthquake,
including rail tracks, fuel tanks, and buildings, were heavily damaged in the 1964 seismic event. The City
of Seward owns the Waterfront Park that now exists adjacent to the shoreline between Ballaine
Boulevard and the ocean, including the green belt bike path. A geologic profile section was developed
along Adams Street, and a 300 ft deep borehole (S-100) was drilled to map the depth of gravel deposits.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 20 OF 38
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DRILLING, CONSTRUCTION, AND TESTING OF TEST BOREHOLE NEAR BIKE PATH AUG 2015
The City secured the services of Denali Drilling of Anchorage in mid July 2015 to install a 300 feet deep x
4 diameter screened test borehole near the Bike Path. The purpose of this test well was to allow
measurement of the subsurface water column and confirm the influence of ocean tides in the aquifer
below. The scope of the work was to drill and drive 6 diameter steel casing to depth, then insert the 4
PVC screened casing; and then extract the steel casing. This work was performed as required, leaving a
4 water column in the test borehole that closely resembles the natural water column in the aquifer.
Once installed, the City rented a Cast-Away marine data logger that could be lowered down the 4 water
column. This data logger sampled temperature, salinity and depth once per second while being lowered
and raised, thus profiling the thermal characteristics of the water column. Data was collected from mid
August thru early September at both high and low tides to determine the difference in ocean tide
influence. The data shows that the deeper portion of the aquifer (180ft to 300ft below water surface)
remains a constant 42F with high salinity. The upper portion of the aquifer (0ft to 180ftbelow water
surface) shows a strong influence of warm subsurface ocean water that peaks about 30 minutes after
high tide. The temperature of ocean tide water in the test borehole closely resembles that measure off-
shore at similar depth. The fact that warm ocean water is moving thru the gravel affords an attractive
opportunity to extract heat from that ocean water via vertical HDPE ground loops that are piped to heat
pumps in nearby buildings. Example temperature and salinity profiles from the data logger are below:
LOW TIDE (-1.6 ft) AUG 18 2015 10:08am HIGH TIDE (+12.1 ft) AUG 31 3:14pm
The sub-surface water table begins at 18ft to 22 ft below grade. Vertical loops inserted in the deep gravel
will then experience full contact with moving tidal water from 20ft below grade to 200 ft below grade, and
full contact with the stationary aquifer from 200ft to 300ft below grade. With 280 ft out of the 300 ft loop
length submerged in water, and the use of double 1 HDPE u-bends in each production hole, it is
anticipated that approximately 3.4 tons of heat pump capacity can be extracted from each production
borehole constructed in this aquifer. This is similar to a fully submerged lake or ocean loop system.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 21 OF 38
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CONCEPTUAL DESIGN OF VERTICAL GROUND LOOPS TO EXTRACT OCEAN HEAT
Vertical ground loops offer several advantages over direct pumping of sea water for the extraction of
ocean heat. By using inert HDPE tubing that acts as a submerged leak tight heat exchanger, vertical
loops eliminate the need for a sea water intake that requires corrosion proof pumps and heat exchanger,
and risks of storm damage, boat anchors and marine bio-fouling. A mixture of water and 20% methanol
is pumped 300 ft down hole in the 1" diameter HDPE tubing and loops back up to the surface, collecting
ground water heat along this path. A series of vertical boreholes spaced 20 feet apart can be piped in
reverse return via horizontal manifold pipes buried 4 ft below the ground surface. This ensures that flow
is split evenly between all boreholes. A single HDPE supply and return trunk line can then deliver the
ground source heat to City buildings via source side loop pumps for the individual heat pumps. Thus the
City has only to operate and maintain a simple closed loop that is pumped from each building at a flow
rate required by the heat pumps in operation at any one time. This approach minimizes pumping energy.
The industry accepted design life of properly installed and buried HDPE ground source loops is 50 years.
Recent ground source heat pump project research in the USA has shown that the heat extraction rate
from a typical vertical ground loop can be increased by approximately 40% by using two loops per hole
that are held in separation by simple "quad bone" clips. These high strength plastic clips are spaced
every four feet along the vertical loops. The clips keep the four HDPE pipes equally spaced at the
perimeter of the bore, so that any one pipe does not lose significant heat to another. In water saturated
gravel this approach affords a marked increase in heat transfer rate as compared to a single loop in the
same borehole.
Discussions with drillers in the region that have certification from the International Ground Source Heat
Pump Association (IGSHPA), suggests the following procedure for 300 feet deep vertical loop installation
in the deep and water saturated alluvial gravels below Waterfront Park near the bike path:
1. Drill and case the 6" diameter borehole to depth of 300 feet. The casing will be needed to keep
the borehole from collapsing due to instability of sand and gravel submerged in the water table.
2. Fill HDPE double loops with water and insert to depth of hole, using a weight to sink the loops
and to anchor end of loops to bottom of hole. Each loop will have round trip length of 600 feet.
3. Extract casing slowly section by section, allowing the natural sand, silt and gravel down the hole
to fall in and fill voids in between the four vertical 1" HDPE u-bend pipes. The option of filling void
space at depth with sand, pea gravel and/or drilling mud via a retractable 1 1/4" tremie pipe,
routed thru the center of the quad bones, may be recommended pending further research.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 22 OF 38
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EXAMPLE PROJECT USING DOUBLE U-BEND VERTICAL LOOPS WITH SEPARATOR CLIPS
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 23 OF 38
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CONCEPT DESIGN OF STARTER GROUND SOURCE DISTRICT HEATING SYSTEM
By using heat pumps sized to displace the heat load on existing oil boilers in the Library, Annex, City Hall,
and Fire Hall, the amount of ground source heat needed for this project can be estimated and several
alternatives can be developed for a district heating system. The first alternative "A" would be a system to
initially serve the Library and Annex, with source loop trunk size for expansion to the City Hall and Fire
Hall. The second alternative "B" would be a system to serve all four city buildings. For both alternatives,
the borehole field and trunk supply and return mains would be sized to meet the peak hourly heat load of
the winter design day of 5F with moderate winds. A table that summarizes the sizing of critical elements
of these two alternatives "A" and "B" is given below. Note that the main trunk noted below is the buried
supply and return pipes that carry ground source flow from the boreholes to the first building (Library).
Peak Hourly Load # Of 6" Dia x 300' Max Source Flow Req'd Trunk
ALT Bldgs Served @5F Winter Day Boreholes Req'd In Main Trunk Pipe Size
"A" LIB + ANX 320,000 BTU/HR 9 100 GPM 3"
"B" All 4 Bldgs 672,000 BTU/HR 17 225 GPM 4"
A concept level piping schematic for ALT A and ALT B is given on the following page. A description of
critical elements of the proposed district heat system is given below:
Borehole Field - Vertical Ground Loops. Boreholes are 20 feet apart and staggered along bike path to
allow equal access to ocean side heat for each vertical loop. A piping manifold along boreholes will be
piped in reverse return configuration, sending and returning an equal amount of flow to each vertical loop.
A 4" diameter full depth (300 ft) test/monitoring hole has already been constructed to confirm the
temperature, salinity and static level of the subsurface water resource. This test well will be used as a
production hole with a single u-bend loop installed to full depth and become part of the final loop field.
Supply & Return Trunk Mains. There exists a nearly straight alignment along the south unpaved shoulder
of Adams Street that currently has no other parallel buried utilities. The alignment from the bike path to
the north wall of the Library includes several water and sewer main crossings, however these lines are at
least six feet deep and the new trunk lines can easily cross above them. The remainder of trunk main
alignment shown from the Library to the Fire Hall is the simplest and most utility free corridor available.
The supply and return mains are essentially one unitary closed loop that will be pressurized to 30 psi at
the highest point (Fire Hall) with a 20% methanol / 80% clean water mixture for anti-freeze protection.
Heat Pumps And Source (Cold) Side Loop Pumps. Each heat pump will receive 25 GPM source side
flow at 36F to 46F and reject heat into 20 GPM load side flow at 125F to 145F. A packaged push/pull
double centrifugal pump station is proposed for the source side loop pumps; this ensures that adequate
flow is delivered thru the long trunk mains and thru the in-line strainer and heat pump evaporator coils.
The source and load side pumps are enabled when the heat pump is enabled by a call for heat.
Load (Hot) Side Loop Pumps & Buffer Tank. Unlike oil fired boilers that are designed to burn hard and
fast to cover the immediate heat load in the hydronic system, heat pumps work best by first supplying a
large buffer storage tank that then supplies the hydronic system. This approach levels out the heat load
that is required of the heat pumps and allows for higher efficiency operation. Additionally it is possible to
also tie the existing oil fired boilers to the buffer tank so they can assist if required. This creates
redundancy and reliability of the heating system and makes use of equipment already installed. The set
point at which the heat pumps will typically reach their capability is 145F. Above 145F the oil boilers may
be needed during extreme cold weather and high winds, or if heat pump units should be off-line.
Connections To Existing Hydronic Systems. All buildings have medium temperature hydronic
baseboards, some also have fan coils or heating coils. The Library has low temperature radiant floors.
With the exception of a few heating coil replacements, the existing hydronic systems will be used.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 24 OF 38
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DRAWING G-1: CONCEPT PLAN OF STARTER HEATING DISTRICT
(11 X 17 PDF OF G-1 CONCEPT PLAN IS ATTACHED SEPARATELY)
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 25 OF 38
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DRAWING G-2: PROJECT SCHEMATIC OF DISTRICT HEATING SYSTEM FOR ALTERNATIVE A
(11 X 17 PDF OF G-2 PROJECT SCHEMATIC IS ATTACHED SEPARATELY)
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 26 OF 38
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TRENCHING OF SUPPLY & RETURN MAINS ALONG AND UNDER CITY STREETS AND ALLEYS
The quantity of open cut trenching required in both shoulder and paved streets to install district source
heat piping is significant for the concept designs presented herein. The recommended strategy to
minimize the cost of trenching, pipe installation, backfilling, and surface restoration is as follows:
For ground source flow, the use of pre-insulated SDR 11 HDPE with field heat fusion joints is
recommended. The insulation will allow the pipe to be installed with the minimum cover of 4 feet
above, and allow the supply and return pipes to lay close together in the trench without heat loss
to each other. The heat fusion joints will ensure long lasting integrity and flexibility of the piping at
shallower depths below road grade. Properly fused HDPE pipe installations operating at low
system pressures (30 to 50 psi) have proven design life of 50 years or more.
The shallow cover depth above the pipe allows open trench excavation without trench boxes or
wide cuts because the risk of trench wall collapse is very low. This reduces the amount of earth
that must be removed and replaced, the cost of pipe installation, and the surface area to be
restored. The shallow depth of the HDPE mains also allows them to pass over both water and
sewer mains without conflict.
The native soil is alluvial sand and gravel and is likely suitable for both bedding and backfill
material; this will reduce the need for importing materials to support and protect the pipe
installation.
The alignment of mains along Adams Street from Ballaine Boulevard to Sixth Street can be
routed in the unpaved shoulder on the south side of Adams Street where no parallel buried
utilities currently exist.
A typical pavement cut and trench section for the largest supply and return source trunk mains (4" inside
diameter HDPE) is shown below. The detail shows that the shallow trench could be kept to a minimum of
4 feet width if native soils will hold a 3'-6" vertical face, this would reduce cost of trenching significantly.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 27 OF 38
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INSULATED AND JACKECTED HDPE SUPPLY AND RETURN GROUND SOURCE MAINS
For district heat piping mains, High Density Polyethylene (HDPE) is a proven, reliable, and structurally
strong choice for core pipe material and standard jacketing. The tough, rugged nature of HDPE
complements its flexibility and structural strength, guarding against cracking, star-crazing or other
damage often caused by abuse or rough handling. HDPE core pipe and jacketed piping is non-corrosive,
requiring no cathode protection or special coatings. The seamless property of HDPE jacketing insures the
watertight integrity of HDPE. Each length of factory-preinsulated pipe is "pressure tested" when
polyurethane foam is injected between the HDPE jacket and the pipe, using state-of-the-art, high
pressure polyurethane foam equipment. The expanding polyurethane foam flows between specially
designed support spacers, completely filling the annular space while exerting pressure against the jacket,
insuring that the jacket is watertight without any pinholes, cracks or crazes that can allow moisture
penetration into the insulation.
Pre-insulated HDPE piping is available in 20 or 40 foot lengths with standard component (HDPE) fittings.
The carrier pipe is high density polyethylene (HDPE), conforming to ASTM D-3350. Pipe and fittings are
manufactured from extra high molecular weight polyethylene compound E4710 and fabricated to
Standard Dimensional Ratio 11 (SDR) wall thickness in standard IPS sizes. Available pressure ratings
range from 50 psi (SDR-32.5) to 255 psi (SDR-7.3) at 73° F, with operating temperatures from -50°F to
+140°F.
The insulation is rigid, 90 to 95% closed cell polyurethane with 2 to 4 pounds per cubic foot density and a
"K° factor of .14 at 75°F per ASTM C 518. The polyurethane foam is CFC free and comply with HH-I-
1751/4. The polyurethane foam is injected into the annular space with low-pressure foam equipment.
Centering spacers are factory-installed to insure uniform insulation around the pipe. Insulation thickness
will be 2" to 3" in thickness.
The outer protective jacket is High Density Polyethylene (HDPE) per ASTM D 1248, Type III, Category 5,
Class C, Grade E4710. The HDPE jacket is seamless and pressure tested for watertight integrity during
foaming. Mastic moisture barriers are factory-applied to each pipe end. End seals are mastic completely
sealing the exposed end of the insulation.
Heat fusion butt-welded fittings are used to join adjacent pipe sections. Fittings are either HDPE butt
fused bare fittings, insulated with a two peace polyurethane foam half shell set with a Polyurea jacket, or
a pre-insulated HDPE fitting with a appropriate HDPE stub. All joints are field-insulated per the
manufacturer's recommendation, using a two-part foam injection method or a pre-formed half shell with a
full-length Aluminum Band.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 28 OF 38
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GROUND SOURCE HEAT PUMP OPERATION AND COEFFICIENT OF PERFORMANCE (COP)
Coefficient Of Performance (COP) for a heat pump is the ratio of total heat output to electricity
input. For ground source heat pump projects, a minimum COP value of 2.8 is desirable as this can lead
to viable economic returns. Ground source heat pumps are water to water heat pumps that operate by
using electricity powered compressors in combination with the physical properties of an evaporating and
condensing fluid known as a refrigerant. The refrigerant used in the heat pumps in this evaluation is
known as R-134a. The vapor compression cycle of the refrigerant is what allows heat to be lifted from
ground temperature (36F to 46F) up to building loop temperature (100F to 140F). When the refrigerant
vapor is compressed, its temperature is raised; this reality of physics is what allows the lifting of heat to
occur at a high efficiency. It is typically far more cost effective to move or lift heat than to make it directly
through the combustion of organic carbon, or through heat of resistance in an electrical element.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 29 OF 38
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SELECTION OF WATER SOURCE HEAT PUMPS SUITABLE FOR USE IN CITY BUILDINGS
The process of removing heat from ground source water and making that same heat useful for space
heating and domestic hot water heating is now both proven and increasingly common in Southcentral
Alaska. The engineering challenge of achieving this for City of Seward is made greater by the distance
that exists between the borehole field near the ocean and the buildings that require heat. The heat
transfer fluid that will be used is clean water with 15% methanol for freeze protection during winter
months. An alternative anti-freeze is propylene glycol, however this choice imposes a reduction in heat
transfer rate, and an increase in pumping cost due to its higher viscosity at colder temperatures.
There are several manufacturers in the USA at this time who have considerable experience with
manufacturing water to water heat pumps that can lift commercial quantities of heat energy from a
temperature range of 35F to 50F on the evaporator side to as great as 140F on the condenser side.
These manufacturer's include Water Furnace and Climate Master who have both developed high quality
models and a healthy competition in the Alaska market. In this evaluation, simulations that define the
glycol flow rates, evaporator and condenser temperatures, coefficient of performance (COP), electricity
demand and heat output, are based on Water Furnace (WF) Series 5 Hi Efficiency 7 Ton Capacity units.
These heat pumps are commercially available as compact self contained units which can be shipped to
Seward, placed on floor stands, and piped and wired in place. A vertical loop ground source heat pump
project completed in the Seldovia House in late 2014 by Cook Inlet Housing Authority is an example:
Concept designs for heat pumps included in this evaluation for City buildings are based upon:
MFG Model Capacity Heat Output Peak Load Dimensions Weight
WF 5 Series 7 Tons 84,000 BTU/Hr 10 KW 34 24 26"W 420 LBS
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 30 OF 38
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SUMMARY OF OPERATION & MAINTENANCE COSTS FOR STARTER DISTRICT HEAT SYSTEM
Like most City owned and operated utilities, a ground source district heating system will have certain on-
going operation and maintenance (O&M) costs throughout its useful design life. It is necessary then to
include costs in the project Net Present Worth Analysis, and account for the escalation rates that will
impact these costs each coming year. The principal elements of O&M cost addressed in this evaluation
for both Alternative A and B are given below and the cost of these elements in Year 1 is estimated:
Electrical energy used by source and load side loop pumps, and by the heat pumps and associated
controls. A single energy monitor will be installed in each building to measure all electrical energy used to
move heat from the ground source loop, through the heat pump, and into the hydronic system.
ALT A (LIB+ANX Only): Electricity - Loop Pumps = 6,220 KWH/yr @$0.184/KWH = $1,145/yr
ALT A (LIB+ANX Only): Electricity - Heat Pumps = 101,110 KWH/yr @$0.184/KWH = $18,770/yr
ALT B (Four City Bldgs): Electricity - Loop Pumps = 12,440 KWH/yr @$0.184/KWH = $2,290/yr
ALT B (Four City Bldgs): Electricity- Heat Pumps = 202,220 KWH/yr @$0.184/KWH = $37,210/yr
Annual monitoring service labor by City staff for the heat pump equipment. One or more individuals on
the City Public Works staff may be assigned to oversee the daily monitoring of performance, and prepare
reports for the City on the system. While the heat pump equipment is covered under standard warranties,
there will be a need for the City to adjust equipment and controls during the design life of the project.
ALT A (LIB + ANX Only): 0.5 hrs/week labor time @ $50/hr x 52 weeks/yr = $750/yr
ALT B (All Four City Bldgs): 0.8 hrs/week labor time @ $50/hr x 52 weeks/yr = $1,200/yr
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 31 OF 38
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COST OPINION - ALT B: GROUND SOURCE DISTRICT HEAT FOR ALL FOUR CITY BUILDINGS
Item Description Installed Installed
Unit Total
Ground Source Borehole Field Quantity Unit Price Price
Mobilization / Demobolization Of Drilling Contractor 1 LS $4,000 $4,000
Drill & Case 6" Vertical Well To 300 FT Depth, 16 Ft Spacing Between Boreholes 16 Each $13,500 $216,000
Install 305 Ft Double U-Bend Loops = 1" Dia HDPE SDR 11 w/Quad Bone Spacers 16 Each $1,800 $28,800
Extract Well Casing To Leave Double U-Bends Intact In Saturated Natural Gravel 16 Each $2,000 $32,000
Remove test well steel casing, install 305 Ft Single U-Bend Loop = 1" Dia HDPE SDR 11 1 Each $1,800 $1,800
Excavate & Backfill 4 Ft Deep Trenching For Borehole Manifolds 160 CY $20 $3,200
Install 3" Dia Insulated Manifold Piping To Connect Vertical Loops - HDPE SDR11 400 LF $25 $10,000
Restore Surface Of Recreation Area 440 SY $10 $4,400
Sub-Total $300,200
Source Trunk Supply & Return Mains Along Adams Street
4" Dia Insulated Supply & Return Main - HDPE SDR11 540 LF $75 $40,500
3" Dia Insulated Supply & Return Main - HDPE SDR11 - LIB to 5th Ave 200 LF $65 $13,000
Flush Ground Source Loop, Charge With Water w/20% Methanol 1 LS $3,400 $3,400
Trench Excavation & Backfill for Supply & Return Mains - 4 Ft Deep Trench 440 CY $20 $8,800
Restore Unpaved Shoulder Along Adams Street 310 SY $15 $4,650.00
Core Drill Holes/Install Sleeves In Library Basement Wall For Supply & Return Main 2 Each $800 $1,600
Restore Base Course & Asphalt Pavement at Ballaine Blvd Crossing 20 SY $75 $1,500.00
Restore Base Course & Asphalt Pavement at 6th Ave Crossing 20 SY $75 $1,500.00
Restore Base Course & Asphalt Pavement In Library Parking Area 40 SY $75 $3,000.00
Sub-Total $77,950
Library Basement Mechanical Room
Construct New Interior Walls & Doorway For District Energy Room In Basement 1 LS $4,000 $4,000
Source Side Piping, Valves & Connections To Loop Pumps & Heat Pumps 1 LS $4,000 $4,000
Source Side Packaged Push/Pull Loop Pumps (WF Flow Center) 25 GPM 4 each $1,000 $4,000
Hi-Efficiency Water Source Heat Pump, 7 Ton, w/ Package Controls 4 each $11,700 $46,800
Load Side Hot Water Buffer Tank - 360 gal - ASME 120 psi Insulated w/6 side taps 1 each $8,000 $8,000
Load Side Circ Pumps, Piping & Connections To Exist Hydronic System 1 LS $6,000 $6,000
Install New Low Temp Heating Coil in Existing Air Handler AHU-2 + Insulated Piping 1 each $3,000 $3,000
Local Power Panel w/Energy Monitor, Elect Power Wiring To Pumps, HPs 1 LS $6,000 $6,000
Instrumentation Devices (Pressure, Temp, Flow), Testing & Commisioning 1 LS $6,000 $6,000
Sub-Total $87,800
Hydronic Hot Water Supply & Return Mains To Serve Annex
Trench Excavation & Backfill - Supply & Return Hot Water Mains - 4 Ft Deep Trench 30 CY $30 $900
Core Drill Holes/Install Sleeves In Annex Basement Wall For Supply & Return Main 2 Each $800 $1,600
1.5" Dia AquaTherm Supply & Return w/2" poly ins & HDPE Jacket, buried 4ft 60 LF $60 $3,600
1.5" Dia AquaTherm Supply & Return w/1.5" FG insulation - Inside To Buffer Tank 80 LF $50 $4,000
Load Side Hot Water Buffer Tank - 120 gal - ASME 120 psi Insulated w/6 side taps 1 each $4,000 $4,000
Load Side Hot Water Circ Pumps, Piping & Connections To Hydronic System 1 LS $4,000 $4,000
Power Wiring - Load Side Pumps; Tank Temp Sensor w/Buried Cable To Library 1 LS $3,000 $3,000
Modify & Upgrade Local HVAC Controls To Integrate Heat Pump/Boiler Operations 1 LS $3,000 $3,000
Instrumentation Devices (Pressure, Temp ), Testing & Commisioning 1 LS $3,000 $3,000
Restore Base Course & Gravel Surface In Alley Between Library & Annex 40 SY $20 $800.00
Sub-Total $27,900
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 32 OF 38
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COST OPINION - ALT B: GROUND SOURCE DISTRICT HEAT FOR ALL FOUR CITY BUILDINGS
(CONTINUED)
Item Description Installed Installed
Unit Total
Source Trunk Supply & Return Mains Along 5th Avenue + City Hall Branch Quantity Unit Price Price
3" Dia Insulated Supply & Return Main - HDPE SDR11 - Up To City Hall 140 LF $65 $9,100
Trench Excavation & Backfill for Supply & Return Mains - 4 Ft Deep Trench 178 CY $20 $3,560
3" Dia Insulated Supply & Return Main - HDPE SDR11-City Hall Branch 60 LF $65 $3,900
Trench Excavation & Backfill for Supply & Return Mains - 4 Ft Deep Trench 18 CY $20 $360
Restore Base Course & Asphalt Paving - Crossing Of Adams Street at 5th Ave 20 SY $75 $1,500.00
Restore Base Course & Asphalt Shoulder Along 5th Avenue 114 SY $75 $8,550.00
Restore Base Course & Asphalt Paving - Crossing Of 5th Ave At City Hall 20 SY $75 $1,500.00
Core Drill Holes/Install Sleeves In City Hall Basement Wall For Supply & Return Main 2 Each $800 $1,600
Restore Sidewalk Where Mains Enter City Hall 6 SY $120 $720.00
Sub-Total $30,790
City Hall Basement Mechanical Room
Source Side Piping, Valves & Connection Of Loops To Heat Pumps 1 LS $4,000 $4,000
Source Side Packaged Push/Pull Loop Pumps (WF Flow Center) 25 GPM 4 each $1,000 $4,000
Hi-Efficiency Water Source Heat Pump, 7 Ton, w/ Package Controls 4 each $11,700 $46,800
Load Side Hot Water Buffer Tank - 360 gal - ASME 120 psi Insulated w/6 side taps 1 each $8,000 $8,000
Load Side Circ Pumps, Piping & Connections To Exist Hydronic System 1 LS $8,000 $8,000
Power Panel w/Energy Monitor, Elect Power Wiring To Pumps, HPs 1 LS $6,000 $6,000
Instrumentation Devices (Pressure, Temp, Flow), Testing & Commisioning 1 LS $6,000 $6,000
Modify & Upgrade Local HVAC Controls To Integrate Heat Pump/Boiler Operations 1 LS $3,000 $3,000
Sub-Total $85,800
Fire Hall Basement Mechanical Room
Trench Excavation & Backfill for Supply & Return Mains - 4 Ft Deep Trench 100 CY $20 $2,000
Core Drill Holes/Install Sleeves In Fire Hall Basement Wall For Supply & Return Main 2 Each $800 $1,600
1.5" Dia AquaTherm Supply & Return w/2" poly ins & HDPE Jacket, buried 4ft 180 LF $60 $10,800
1.5" Dia AquaTherm Supply & Return w/1.5" FG insulation - Inside To Buffer Tank 20 LF $50 $1,000
Restore Base Course & Gravel Surface In Alley Between City Hall & FireHall 120 SY $20 $2,400.00
Load Side Hot Water Buffer Tank - 120 gal - ASME 120 psi Insulated w/6 side taps 1 each $4,000 $4,000
Load Side Circ Pumps, Piping & Connections To Exist Hydronic System 1 LS $4,000 $4,000
Power Wiring - Load Side Pumps; Tank Temp Sensor w/Buried Cable To City Hall 1 LS $3,000 $3,000
Instrumentation Devices (Pressure, Temp ), Testing & Commisioning 1 LS $3,000 $3,000
Modify & Upgrade Local HVAC Controls To Integrate Heat Pump/Boiler Operations 1 LS $3,000 $3,000
Sub-Total $34,800
Total Installation Cost Opinion for ALT B $645,240
City Project Manager/Administration $37,000
14% for final design services $83,880
3% for construction phase services $19,356
10% Contingency $64,524
Total Project Cost Opinion - ALT B: Ground Source District Heat For All Four City Buildings $850,000
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 33 OF 38
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APPENDIX A: ANNEX BUILDING - OIL BOILER - FUEL USE VS. OUTSIDE TEMP - DATA LOGGER
Note: Closest temperature data base set available in energy software was Kodiak. Seward temperatures
are about 5 F colder on average, and accordingly fuel use may be slightly higher than shown.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 34 OF 38
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APPENDIX B: FIRE HALL - OIL BOILER - FUEL USE VS. OUTSIDE TEMP - DATA LOGGER
Note: Closest temperature data base set available in energy software was Kodiak. Seward temperatures
are about 5 F colder on average, and accordingly fuel use may be slightly higher than shown.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 35 OF 38
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APPENDIX C: CITY HALL - OIL BOILER - FUEL USE VS. OUTSIDE TEMP - DATA LOGGER
Note: Closest temperature data base set available in energy software was Kodiak. Seward temperatures
are about 5 F colder on average, and accordingly fuel use may be slightly higher than shown.
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 36 OF 38
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APPENDIX D: QUOTE TO DRILL AND INSTALL 2 TEST HOLES & 10 VERT GROUND LOOPS
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 37 OF 38
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APPENDIX E: QUOTE FOR INSULATED HDPE PIPE WITH JACKET- SUPPLY & RETURN MAINS
GSHP SYSTEM EVALUATION FOR CITY BLDGS CITY OF SEWARD 9/12/15 PAGE 38 OF 38
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APPENDIX F: QUOTE FOR HEAT PUMPS, LOOP PUMPS, BUFFER TANKS, U-BEND COILS