HomeMy WebLinkAboutJuneau Airport Ground Source Heat Pump Project Feasibility Study - Dec 2007 - REF Grant 2195359Alaska Energy Engineering LLC TECHNICAL MEMORANDUM
25200 Amalga Harbor Road Tel/Fax: 907.789.1226 December 2007
Juneau, Alaska 99801 alaskaenergy@earthlink.net
to: Dave Palmer, Airport Manager
Catherine Fritz, Airport Architect
subject: Ground Source Heat Pump Feasibility Study: Life Cycle Cost Analysis
project: JNU Terminal Renovation and Expansion
INTRODUCTION
This report presents a life cycle cost analysis of a ground source heat pump (GSHP) system for the
JNU Terminal. A GSHP system represents a significant change from the traditional heating,
ventilating, and air-conditioning (HVAC) system that has been proposed for the JNU Terminal
building. The intent of this report is to compare the life cycle cost of the two systems.
The terminal expansion and renovation will happen over several phases, including the complete
replacement of the older commuter terminal. Since a timeframe and exact scope is presently
unknown, the analysis has been simplified by assuming that renovation of the entire terminal building
will be performed in 2009 in one project. It is believed that this approach will not significantly alter
the findings.
The life cycle cost comparison presented in this analysis represents total life cycle costs over 25-
years. The analysis assumptions that all construction costs occur in Year 0 and all maintenance and
energy costs occur equally over 25-years presents valid cost comparison of the systems. Since the
renovation will actually occur over two or more phases of construction, actual construction,
maintenance, and energy costs are likely to be different than present in this report.
DESCRIPTION OF HVAC SYSTEMS
Proposed HVAC Scheme
The HVAC scheme that has been proposed for the JNU Terminal consists of variable air volume
ventilation systems and a fuel-oil heating system using hydronic boilers. Domestic hot water is
generated by indirect hot water tanks heated by the hydronic boiler system.
This scheme is similar to the existing terminal HVAC systems with the following features that
providing greater energy efficiency:
The proposed heating plant has three smaller boilers which can better match the heating load,
improving seasonal efficiency. The existing plant has two large boilers.
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The proposed ventilation system uses a variable air volume system with supply air temperature
reset control to reduce the energy required to reheat the supply air at each zone. The existing
systems are constant air volume with no reset control.
The proposed ventilating system uses a demand control ventilation (DCV) strategy to reduce
ventilation air when the building occupancy is less than design. The highly variable occupancy of
the building allows the DCV strategy to reduce the ventilation air by an average of over 50%, yet
maintain adequate indoor air quality.
Ground Source Heat Pump Scheme
Ground source heat pump systems exchange heat with the ground to heat and cooling the building.
The GSHP scheme has an array of closed-loop vertical well field connected to water-to-air heat
pumps distributed throughout the terminal.
The vertical well field will require 215 wells, each 175’ deep. The wells will be spaced 10’ apart and
each will contain a 3/4” HDPE pipe loop. The analysis assumes two well fields located within 200’ of
the terminal building. The well field was sized based on an industry standard of 300 feet of well per
ton of heating load.
Water circulating through the well field gains heat from the ground. The heat pumps remove this heat
from the water and, using a compressor/condenser cycle, distribute it via warm air to the rooms. The
system will also provide cooling by rejecting heat to the ground, but for our heating-dominant climate
this report will focus on heating operation.
Ventilation air is supplied by a dedicated outdoor air system (DOAS). The DOAS is a central heat
recovery system that transfers heat from exhaust air to preheat ventilation air that is supplied to each
heat pump. A DCV scheme is used to vary the amount of outside air delivered to each heat pump with
building occupancy.
Domestic hot water is generated by domestic hot water heat pumps (DHWHPs) that are also coupled
to the ground loop. The DHWHPs produce hot water which is stored in tanks.
Other Ground Coupling Options
The analysis is based on a closed-loop vertical well field ground couple that has been successfully
used by AEL&P in their office building. It is a dependable, proven scheme that will work well for the
terminal. Other ground coupling opportunities also exist at the site but were not pursued. These are:
Open-loop Method (Pump and Dump): This method extracts heat from ground water and
reinjects it into the ground or discharges it to surface flows. The site is likely to have sufficient
ground water and obtaining a water right should not be a problem. It is used extensively in other
regions because it has lower construction costs, which are partially offset by higher maintenance
and pumping costs than a closed-loop system.
Submerged Closed Loop System: This method would use the float plane pond as a ground couple
for the system. Pipe loops would be placed in the pond to extract heat. There is an opportunity to
integrate the loop installation with the pond dredging project that will occur in near future.
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While both of these methods are likely to have lower construction costs, they are not recommended
because they bring higher risks to the project. The open-loop method has operational concerns with
ground water quality and low ground water temperatures. The submerged system has concerns about
whether to pond size is adequately sized given that our heating dominated climate. Other concerns
include designing the pipe loops so they can be routinely cleaned of algae and other vegetative
growth while maintaining flight operations.
HVAC Scheme Comparison
System Proposed Scheme GSHP Scheme
Ventilation System Variable air volume Dedicated outdoor air system
air handling units (AHU) supplying each heat pump
Heating and Cooling Fuel-oil fired boilers Water-to-air heat pumps (61);
hydronic heating units Closed loop vertical well field
Electric chiller supplying
AHU cooling coils
Snowmelt System Hydronic heat via boilers Water-to-water heat pump
Domestic Hot Water System Indirect HW tanks heated Domestic hot water heat
by the boilers pumps and HW storage tanks
ENERGY ANALYSIS
Energy Costs
Fuel Oil
Fuel oil currently costs the CBJ over $3.00 per gallon. On average, fuel oil prices have risen 31% per
year for the past 2-years, 16% per year over the past 5-years, and 6.3% per year for the last 15-years.
The analysis assumes fuel oil costs will inflate at 5% per year for the next 25 years, which is lower
than recent history. This represents a deliberate decision to underestimate fuel oil inflation, lending
conservatism to the analysis. The cost of fuel oil is predicted to be today’s cost of $3.00 per gallon
inflated at 5% per year to $3.31 per gallon in 2009.
Electricity
The terminal is billed under Alaska Electric Light & Power (AEL&P) Schedule 25 – Large
Commercial. It is assumed that a rate increase will not occur prior to 2009.
Electricity inflation has historically been under 1% per year but it is expected to be higher in the
future as the community uses up its hydroelectric surplus and buys more expensive power from new
hydroelectric sources and/or supplements with diesel power. The rising cost of fuel oil will also
increase electric heating loads, placing more demand on the electric generation system. The analysis
assumes these factors will cause electricity inflation to triple to an average of 3% per year over the
next 25-years.
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Economic and Energy Factors
Factor Rate or Cost Factor Rate or Cost
Nominal Discount Rate 5.5% Electricity Rate Current AEL&P rates
General Inflation Rate 2.8% Electricity Inflation 3.0%
Real Discount Rate 2.6% Fuel Oil Cost (2009) $3.31/gal
Fuel Oil Inflation 5.0%
Findings
The GSHP scheme has considerably lower energy costs than the proposed scheme. As shown in the
following table, heating costs are the largest difference.
Annual Energy Cost Comparison
Component Proposed Scheme GSHP Scheme
Heating $135,000 $37,400
Fans 10,200 13,000
Pumps 2,300 9,000
Cooling 2,100 5,500
Total Cost $150,000 $64,900
Heating costs are the primary difference between the two systems. This result has been carefully
scrutinized, as the difference is remarkable. There following factors contribute the most to the
findings:
The GSHP scheme is much more efficient at converting purchased energy into heat. While the
fuel oil boilers are 69% efficient at converting fuel oil to heat, the heat pumps are 260% efficient
at converting electricity to heat. The 260% efficiency occurs because for each purchased BTU,
the system extracts 1.6 BTUs from the ground and delivers 2.6 BTUs to the building.
The GSHP scheme benefits from using a lower cost energy source. Fuel oil at $3.31 per gallon
and a conversion efficiency of 69% costs 11.8¢ per kWh of delivered heat. Currently, the terminal
is paying an effective electricity cost—combined energy and demand charges—of 6.7¢ per kWh.
A GSHP system will cause an increase in the effective cost of electricity—due to higher demand
charges—to 7.9¢ per kWh. This cost is 33% lower than the cost of fuel oil heat at 11.8¢ per kWh.
The GSHP scheme is systemically more efficient than the proposed scheme. The proposed
scheme is essentially a central cooling system that must reheat the air supplied to zones that do
not require cooling. This reheat energy penalty is larger in our heating-dominated climate than in
warmer climates. The distributed heat pump scheme adds heating and cooling as needed at each
zone and does not have a reheat penalty.
With the GSHP scheme, it is much easier to reduce ventilation air and turnoff the HVAC in areas
that are unoccupied, such as offices during nights and weekends.
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The following factors contribute to the other energy cost components:
Fan Energy: The fan energy is about the same for both systems. The proposed fans are more
efficient but they move air longer distances, resulting in nearly equal energy costs.
Pumping Energy: The GSHP scheme has much higher pumping costs because more water flows
through the well field. This cost partially offsets the energy cost savings.
The proposed scheme is more efficient at cooling because it is capable of naturally cooling using
outside air. The GSHP system must mechanically cool.
LIFE CYCLE COST ANALYSIS
The life cycle cost analysis determined that a GSHP system has the lowest life cycle cost. The
proposed fuel oil system will cost $8,950K and the GSHP system $7,880K over 25-years. The
following table shows the life cycle cost comparison.
Life Cycle Cost Comparison, $K
Heating System Proposed System GSHP System
Construction Cost $5,230K $6,050K
Maintenance Cost 270K 640K
Energy Cost 3,450K 1,190K
Total Cost $8,950K $7,880K
Discussion
The life cycle cost comparison of the two systems reveals that the GSHP system has a life cycle cost
savings of $1.1M or 12%. The GSHP system has higher construction and maintenance costs, but
these costs are more than offset by considerably lower energy costs. The following points are relevant
to the findings.
Construction Costs
GSHP schemes typically require a larger upfront investment. The analysis has confirmed that this is
the case for the JNU Terminal.
The cost of coupling to the ground is highly dependent upon an experienced contractor willing to
come to Juneau and install the well field. A Seattle-based company provided a preliminary
estimate for the analysis. Their estimate was increased 33% to account for Alaska cost factors,
working within an operating airport tarmac, and variations in subsurface conditions.
Three separate ground loops are included in the costs for redundancy.
A test well has been drilled at the airport site and indicates that the site is highly suited for a
vertical well field.
The heat pumps will be located above ceilings. This has a positive effect on construction costs as
it reduces mechanical space and the length of duct runs for each zone. The heat pumps will
generate noise above the ceilings. Locating them in non-sensitive areas can mitigate this issue.
Alaska Energy Engineering LLC Page 6
It is common in cold climates to supply heat along the building perimeter to improve occupant
comfort. Since much of the terminal has a transient occupancy that is dressed for the weather, this
is less of a concern. Modern buildings also have greatly improved thermal envelopes which also
reduce the need for perimeter heat. If perimeter heat is desired in the office areas, the GSHP
system can accommodate this need by supplying heating air along the perimeter during cold
weather.
GSHPs are supplied with standalone PLC controllers and do not require interface with a building
automation system. However, it is desirable to have central control and monitoring of the HVAC
systems. The analysis assumes a similar computer-based DDC monitoring and control interface
for each system.
Maintenance Costs
A distributed HVAC scheme, such as the GSHP system, has more terminal components and moving
parts located above ceilings. This increased number of moving parts coupled with their location above
ceilings in occupied areas, increases maintenance efforts and costs. The analysis assumes airport
maintenance staff will obtain the expertise to maintain and repair both systems without contracting
for specialized technicians.
Energy Costs
Contributing to the annual energy cost difference of the two systems is that fuel oil is projected to
inflate at 5% per year and electricity at 3% per year.
The energy analysis model is incapable of simulating the real-world variations in electric demand that
are likely to occur with an electrically heated building. To account for this likely increase in
electricity costs, building demand costs are increased by 50% in recognition that demand surges are
likely.
RECOMMENDATION
While a GSHP scheme represents a notable departure from the existing HVAC scheme in the
building, it is a viable, dependable system for heating, ventilating, and air-conditioning the JNU
Terminal. The life cycle cost comparison shows the GSHP scheme has a much lower life cycle cost.
GSHP schemes have also been considered for the Juneau Police Station (1996) and Juneau’s Thunder
Mountain High School (2001). In those cases, the GSHP scheme did not have the lowest life cycle
cost, primarily because the analysis was based on much lower projections of fuel oil prices and
inflation. If actual fuel oil inflation was used, the findings are likely to have been different.
For the JNU Terminal, fuel oil prices would have to be $2.20 per gallon in 2009 (instead of a cost of
$3.31 per gallon that is used in the analysis)—with all other assumptions being equal—for both
systems to have an equal life cycle cost. The high fuel oil inflation of the past 5 years has provided
the financial incentive to invest in GSHP technology.
It is recommended that a GSHP scheme be used for the HVAC systems at the JNU Terminal. The
following factors contribute to this recommendation:
The site offers several options for coupling to the ground, including sufficient space for a vertical
well field and favorable soil conditions.
The GSHP scheme is more suited to reducing ventilation air when the building occupancy is
below design levels (most of the time).
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The building operates 24/7, which offers the GSHP scheme the greatest opportunity to recoup the
initial investment through annual energy savings.
The system is capable of transferring heat from high heat gain areas to other areas where heating
is needed. Since the population moves through the building in groups as planes arrive and depart,
the system can more efficiently deal with the variations in load.
The system allows for unoccupied spaces—offices, community meeting room, customs—to be
turned off when not in use.
GSHP Scheme Design
The primary goal of any HVAC scheme is to provide adequate indoor air quality and maintain
occupant comfort. For the GSHP scheme to achieve these goals at the lowest life cycle cost, it is
recommended that the following issues be considered during design and construction of the system:
Noise Mitigation: The heat pumps will generate fan and compressor noise above ceiling. The
design should reduce noise concerns by located the units in non-noise sensitive areas or
mechanical rooms and using materials that absorb sound.
Maintenance Access: The heat pumps must be installed with adequate clearance for maintenance
and eventual replacement of the unit.
Perimeter Heat: In areas where perimeter heat is deemed necessary, heat pumps can be used to
continuously supply warm air along the perimeter during cold weather. Another more expensive
option is to use a water-to-water heat pump to provide perimeter hydronic heat.
Hybrid System: A hybrid system uses a boiler (electric is preferred over fuel oil) to supply
supplemental heat during cold weather. This allows the well field to be downsized, saving
significantly on construction costs. Typically, the well field is sized for 70% of the design heating
load, which is usually sufficient for heating the building when lights and equipment are operating.
Water-side Economizers: GSHPs can be supplied with a water-side economizer feature which
allows cooling with the ground source water rather than by using the compressor. This option is
applicable to this site since ground water temperatures are likely to be cool enough during
summer air-conditioning periods.
Heat Pumps with Variable Speed Compressors: Variable speed compressors allow the heat pump
to deliver air with less temperature swings than compressors that cycle on and off. This will
improve the thermal comfort in areas such as offices where occupants are more sensitive to
temperature variations.
Heat Pump DOAS System: A variable speed heat pump can be used for the DOAS so that
ventilation air is always supplying at the same temperature as the building. This will decrease
temperature swings as heat pumps cycle on and off.
Conclusion
A GSHP scheme offers the financial incentive to move away from traditional fuel oil-based HVAC
systems to a system that extracts heat from the environment and obtains most of its purchased energy
from cleaner hydroelectric resources. As such, the GSHP scheme offers the JNU Terminal a lower
cost HVAC system that is also more sustainable.
by:
Jim Rehfeldt, P.E.
Alaska Energy Engineering LLC Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 alaskaenergy@earthlink.net
JNU Terminal Renovation and Expansion
Alternative #1: Proposed HVAC Scheme
Basis
25 Study Period (years) 2.8% General Inflation
5.5% Nominal Discount Rate 5.0% Fuel Inflation
2.6% Real Discount Rate 3.0% Electricity Inflation
Construction Costs Qty Unit Base Cost Year 0 Cost
Commercial Terminal
Demolition
Per Schematic Cost Estimate 1 job 40,000.00 40,000
Fuel Oil System
5,000 gallon buried tank complete with piping, monitoring 1 ea 42,750.00 42,750
50 gallon day tank, piping, connections 1 ea 8,225.00 8,225
Penthouse Mechanical Room
Per Schematic Cost Estimate 1,820 sqft 320.00 582,400
Heating Plant
Boilers - 750 MBH ea with controllers and chimneys 3 ea 21,000.00 63,000
Primary Loop - pumps, boiler header 3 ea 7,200.00 21,600
Secondary Loop - ex. tank, separator, pumps, piping 1 job 20,000.00 20,000
Snowmelt System
Heat exchanger 1 ea 3,900.00 3,900
Boiler side piping 1 lot 10,000.00 10,000
Domestic Hot Water System
300 gallon indirect HW heater, hw pump, piping, etc. 1 lot 12,225.00 12,225
Hydronic Heating System
Unit heaters 7 ea 1,250.00 8,750
Terminal box reheat coil and valves 18 ea 745.00 13,410
Reheat coils 12 ea 660.00 7,920
Finned tube baseboards, valves, controls 362 lnft 59.00 21,358
Baseboard enclosure 480 lnft 21.00 10,080
Insulated hydronic piping (3/4" to 3"), supports, seismic 2,440 lnft 42.00 102,480
Ventilation
AHU-1: 30,000 CFM supply fan, 23,000 CFM return fan, VFD s 30,000 cfm 5.25 157,500
3,000 CFM boiler room combustion air fan 3,000 cfm 5.50 16,500
2,500 CFM main exhaust fan 2,500 cfm 2.50 6,250
100 CFM janitor closet and small toilet exhaust fans 4 ea 415.00 1,660
VAV boxes 30 ea 675.00 20,250
Grilles and diffusers 184 ea 137.00 25,208
Sheetmetal ductwork, insulation, lining, hangers 18,550 lbs 8.75 162,313
Sound attenuators 1 lot 10,000.00 10,000
Outside air louver and damper 100 sqft 57.00 5,700
Miscellaneous dampers, etc. 1 lot 4,000.00 4,000
Cooling
50 ton roof mounted chiller and circ pump 1 ea 65,820.00 65,820
Chilled water insulated piping (2" to 3/4"), glycol 800 lnft 36.50 29,200
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Alaska Energy Engineering LLC Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 alaskaenergy@earthlink.net
JNU Terminal Renovation and Expansion
Alternative #1: Proposed HVAC Scheme
December 14, 2007
Construction Costs Qty Unit Base Cost Year 0 Cost
Controls
New DDC system 200 pts 1,625.00 325,000
Start up
Test, balance and commission 325 hrs 150.00 48,750
Electrical
3-phase circuits: pumps, ahu, rf 9 ea 2,500 22,500
1-phase circuits: boilers, fans 7 ea 1,500 10,500
Commuter Terminal
Mechanical Room
Fan Room 750 sqft 320.00 240,000
Hydronic Heating System
Unit heaters 3 ea 1,250.00 3,750
Terminal box reheat coil and valves 12 ea 745.00 8,940
Reheat coils 8 ea 660.00 5,280
Finned tube baseboards, valves, controls 400 lnft 59.00 23,600
Baseboard enclosure 500 lnft 21.00 10,500
Insulated hydronic piping (3/4" to 3"), supports, seismic 3,400 lnft 42.00 142,800
Ventilation
AHU-2: 20,000 CFM supply fan, 17,000 CFM return fan, VFD s 20,000 cfm 5.50 110,000
SF-1 Kitchen Makeup: 4,600 CFM 4,600 cfm 6.00 27,600
Kitchen hood exhaust fan 4,600 cfm 1.00 4,600
2,500 CFM main exhaust fan 2,500 cfm 2.50 6,250
100 CFM janitor closet and small toilet exhaust fans 2 ea 415.00 830
VAV boxes 20 ea 675.00 13,500
Grilles and diffusers 125 ea 137.00 17,125
Sheetmetal ductwork and hangers 23,000 lbs 8.75 201,250
Sound attenuators 1 lot 8,000.00 8,000
Outside air louver and damper 80 sqft 57.00 4,560
Miscellaneous dampers, etc. 1 lot 4,000.00 4,000
Cooling
30 ton roof mounted chiller and circ pump 1 ea 52,000.00 52,000
Chilled water insulated piping (2" to 3/4"), glycol 800 lnft 36.50 29,200
Controls
DDC system 100 pts 1,625.00 162,500
Start up
Test, balance and commission 200 hrs 150.00 30,000
Electrical
3-phase circuits: pumps, ahu, rf 5 ea 2,500 12,500
1-phase circuits: fans 2 ea 1,500 3,000
CONTINGENCIES
Premium time 1,300 hrs 65.00 84,500
Subcontractors OH&P 15% 462,830
General Contractor OH&P 34% 1,206,444
Estimating contingency 10% 475,481
Total Construction Costs $5,230,000
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Alaska Energy Engineering LLC Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907.789.1226
Juneau, Alaska 99801 alaskaenergy@earthlink.net
JNU Terminal Renovation and Expansion
Alternative #1: Proposed HVAC Scheme
December 14, 2007
Annual Costs Qty Unit Base Cost Present Value
Replacement Costs
Pipe mounted pumps: one $1600 pump every eight years 1 - 25 1 ea 200.00 3,538
Base mounted pumps 12 - 12 2 ea 2,500.00 3,568
Indirect HW heaters 12 - 12 1 ea 8,000.00 5,709
Maintenance Costs
Boiler maintenance: 3 @ 40hrs/ea 1 - 25 60 hrs 50.00 53,064
Pump maintenance: 5 @ 8 hrs/ea 1 - 25 40 hrs 50.00 35,376
Hot water tank maintenance 1 - 25 6 hrs 50.00 5,306
Hydronic system maintenance 1 - 25 30 hrs 50.00 26,532
Miscellaneous parts 1 - 25 1 lot 2,000.00 35,376
AHU maintenance (2 @ 10 hrs ea) 1 - 25 20 hrs 50.00 17,688
Chiller 1 - 25 10 hrs 100.00 17,688
Exhaust fans 1 - 25 4 hrs 50.00 3,538
DDC system 1 - 25 1 job 3,000.00 53,064
Fuel monitoring calibration 1 - 25 4 hrs 100.00 7,075
Total Annual Costs $268,000
Energy Costs Qty Unit Base Cost Present Value
Fuel Oil 1 - 25 40,825 gals 3.31 3,176,412
Electricity 1 - 25 212,000 kWh 0.0697 274,416
Total Energy Costs $3,451,000
$8,949,000Present Worth
Years
Years
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Alaska Energy Engineering LLC Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 alaskaenergy@earthlink.net
JNU Terminal Renovation and Expansion
Closed Loop Ground Source Heat Pump System
Basis
25 Study Period (years) 2.8% General Inflation
5.5% Nominal Discount Rate 5.0% Fuel Inflation
2.6% Real Discount Rate 3.0% Electricity Inflation
Construction Costs Qty Unit Base Cost Year 0 Cost
SITE WORK
Demolition
Remove paving 25,600 sqft 0.75 19,200
Closed loop vertical well field
Vertical ground exchange wells
Mob/Demob to/from barge lines 2 RT 4,000.00 8,000
Shipping 1 LOT 10,000.00 10,000
Drill rig transportation and down time 10 days 5,000.00 50,000
Per Diem; 3 people, 60 days 180 days 175.00 31,500
Drill cased hole, install 3/4" HDPE loop, remove casing, backfill 37,505 lnft 20.00 750,100
Grout plug between aquifers 215 holes 100.00 21,500
Exterior piping
Excavate and backfill trench and wells 870 cuyd 11.00 9,570
Install 4" HDPE, SDR 11 mains in trench 2,520 lnft 15.00 37,800
Install 2-1/2" HDPE, SDR 11 in trench 360 lnft 12.00 4,320
Install 2" HDPE, SDR 11 in trench 720 lnft 10.00 7,200
Install 1-1/2" HDPE, SDR 11 in trench 720 lnft 7.60 5,472
Install 3/4" HDPE, SDR 11 in trench 4,500 lnft 6.10 27,450
Connect supply and return to well 216 ea 125.00 27,000
Sub base and leveling course 630 cuyd 30.00 18,900
Paving 25,600 sqft 5.00 128,000
COMMERCIAL TERMINAL
Demolition
Per Schematic Cost Estimate 1 job 40,000.00 40,000
Additional hydronic heating system demo 1 job 20,000.00 20,000
Additional duct system demo 1 job 40,000.00 40,000
Additional domestic hot water system demo 1 job 5,000.00 5,000
Penthouse Mechanical Room
Mech space for DOAS, water-to-water HPs, DHWHP 800 sqft 320.00 256,000
Hydronic Ground Source System
Source manifold
6" HDPE SDR 11 manifold 40 lnft 55.70 2,228
4" HDPE SDR 11 ground loop piping 50 lnft 37.20 1,860
Manifold valves, gauges, appurtenances 1 ea 3,500.00 3,500
Source pumps, 225 gpm @ 150' head, 15 HP, VFD 3 ea 6,500.00 19,500
Expansion tank, separator, glycol mixing tank 1 job 6,000.00 6,000
Insulated hydronic HDPE piping (3/4" to 6"), supports, seismic 1,800 lnft 25.00 45,000
Snowmelt System
120 MBH water-to-water heat pump 1 ea 20,000.00 20,000
Source side
3" HDPE WWHP piping 60 lnft 37.20 2,232
Manifold piping, valves and gauges 1 ea 2,750.00 2,750
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Alaska Energy Engineering LLC Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 alaskaenergy@earthlink.net
JNU Terminal Renovation and Expansion
Closed Loop Ground Source Heat Pump System
December 14, 2007
Construction Costs Qty Unit Base Cost Year 0 Cost
Domestic Hot Water System
120 MBH water-to-water heat pump 2 ea 20,000.00 40,000
Source side
3" HDPE WWHP piping 90 lnft 37.20 3,348
Manifold piping, valves and gauges 2 ea 2,750.00 5,500
300 gallon HW tank 2 lot 7,500.00 15,000
Ventilation
Dedicated Outdoor Air Systems
DOAS-1: 7,000 CFM HP with HRU, VFD s 7,000 cfm 4.00 28,000
DOAS ductwork to each HP 12,000 lbs 8.75 105,000
Outside air louver and damper 50 sqft 57.00 2,850
Miscellaneous dampers, etc. 1 lot 2,000.00 2,000
100 CFM janitor closet and small toilet exhaust fans 4 ea 415.00 1,660
Water-to-air heat pump, 0.5 ton, ductwork, loop and elect conn. 2 ea 5,000.00 10,000
Water-to-air heat pump, 1 ton, ductwork, loop and elect conn. 6 ea 5,500.00 33,000
Water-to-air heat pump, 1.5 ton, ductwork, loop and elect conn. 5 ea 6,000.00 30,000
Water-to-air heat pump, 2 ton, ductwork, loop and elect conn. 1 ea 6,500.00 6,500
Water-to-air heat pump, 2.5 ton, ductwork, loop and elect conn. 11 ea 7,000.00 77,000
Water-to-air heat pump, 3 ton, ductwork, loop and elect conn. 2 ea 7,500.00 15,000
Water-to-air heat pump, 5 ton, ductwork, loop and elect conn. 2 ea 9,000.00 18,000
Grilles and diffusers 184 ea 137.00 25,208
Controls
Heat pump DDC interface (29 HP @ 8 pts ea)232 pts 1,100.00 255,200
Ground loop pumps, DOAS, EF, etc.25 pts 1,625.00 40,625
Start up
Test, balance and commission 500 hrs 150.00 75,000
Electrical
Additional electrical panels and feeds 2 ea 18,000 36,000
3-phase circuits: HP and DOAS 18 ea 2,500 45,000
1-phase circuits: boilers, fans 13 ea 1,500 19,500
COMMUTER TERMINAL
Mechanical Room
For DOAS, DHWHP 400 sqft 320.00 128,000
Hydronic Ground Source System
Insulated hydronic HDPE piping (3/4" to 6"), supports, seismic 2,500 lnft 25.00 62,500
Ventilation
Dedicated Outdoor Air Systems
DOAS-2: 3,000 CFM HP with HRU, VFD s 3,000 cfm 4.00 12,000
DOAS ductwork to each HP 8,000 lbs 8.75 70,000
100 CFM janitor closet and small toilet exhaust fans 4 ea 415.00 1,660
Water-to-air heat pump, 1 ton, ductwork, loop and elect conn. 20 ea 5,500.00 110,000
Water-to-air heat pump, 1.5 ton, ductwork, loop and elect conn. 2 ea 6,000.00 12,000
Water-to-air heat pump, 2 ton, ductwork, loop and elect conn. 1 ea 6,500.00 6,500
Water-to-air heat pump, 2.5 ton, ductwork, loop and elect conn. 3 ea 7,000.00 21,000
Water-to-air heat pump, 3 ton, ductwork, loop and elect conn. 3 ea 7,500.00 22,500
Water-to-air heat pump, 6 ton, ductwork, loop and elect conn. 1 ea 10,000.00 10,000
Water-to-air heat pump, 12.5 ton, ductwork, loop and elect conn. 2 ea 15,000.00 30,000
Grilles and diffusers 184 ea 137.00 25,208
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Alaska Energy Engineering LLC Life Cycle Cost Analysis
25200 Amalga Harbor Road Tel/Fax: 907-789-1226
Juneau, Alaska 99801 alaskaenergy@earthlink.net
JNU Terminal Renovation and Expansion
Closed Loop Ground Source Heat Pump System
December 14, 2007
Construction Costs Qty Unit Base Cost Year 0 Cost
Outside air louver and damper 40 sqft 57.00 2,280
Miscellaneous dampers, etc. 1 lot 2,000.00 2,000
Controls
Heat pump DDC interface (32 HP @ 8 pts ea)256 pts 1,100.00 281,600
Ground loop pumps, DOAS, EF, etc.18 pts 1,625.00 29,250
Start up
Test, balance and commission 250 hrs 150.00 37,500
Electrical
Additional electrical panels and feeds 2 ea 18,000 36,000
3-phase circuits: HP and DOAS 12 ea 2,500 30,000
1-phase circuits: boilers, fans 22 ea 1,500 33,000
CONTINGENCIES
Premium time 1,500 hrs 65.00 97,500
Subcontractors OH&P 15% 535,496
General Contractor OH&P 34% 1,395,859
Estimating contingency 10% 550,133
Total Construction Costs $6,051,000
Annual Costs Qty Unit Base Cost Present Value
Replacement Costs
Test, balance and commission 2 ea 7,000.00 14,000
Water-to-air heat pump 1 - 25 3.0 ea 1,500.00 79,597
DHWHP 15 - 15 2 ea 20,000.00 26,404
Ground loop pumps 12 - 12 2 ea 6,500.00 9,276
Maintenance and Repair Costs
Water-to-air heat pump (61 @ 6 hrs ea) 1 - 25 366 hrs 55.00 356,063
Water-to-water heat pumps (3 @ 2 hrs ea) 1 - 25 6 hrs 55.00 5,837
DOAS HRU (2 @ 10 hrs ea) 1 - 25 20 hrs 55.00 19,457
Ground loop system: pumps, glycol, gages 1 - 25 10 hrs 55.00 9,728
DDC system 1 - 25 1 job 2,000.00 35,376
Miscellaneous parts 1 - 25 1 lot 5,000.00 88,441
Total Annual Costs $644,000
Energy Costs Qty Unit Base Cost Present Value
Fuel Oil 1 - 25 gal 3.31 0
Electricity 1 - 25 656,000 kWh 0.070 852,791
Increased demand charges (50% greater than prediction) 1 - 25 1,650 kW 11.00 337,068
Total Energy Costs $1,190,000
$7,885,000
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