2864 Installation Costs

Application-specific parameters, such as equipment capacity, type, refrigerant, air-distribution system, control system, plumbing configuration, and ground-coupling system type, significantly affect the total cost of the overall system. While equipment costs are competitive, installation costs vary significantly.

To illustrate the potential range of installation costs, the following examples have been reported.

• Stockton State College in Pomona, New Jersey, retrofit a system that totaled 1,655 tons (5,826 kW) at a total cost of $5,246,000 (Gahran 1993). The facility received grants and rebates reducing the capital outlay to $135,000. The system included 63 rooftop units, 500 variable-air-volume (VAV) boxes, and a 3,500- point energy management control system (EMCS). The unit cost was $3,170/ton in 1993 dollars.

• WaterFurnace, a ground-source heat pump manufacturer, designed the technology using a submerged pond closed-loop system into its new office building located in Fort Wayne, Indiana. The system totaled 134 tons (471.7 kW) at a cost of $239,800 (Wa-terFurnace WF639). The unit cost was $1,790/ton in 1991 dollars.

• Salem Community College in Carney's Point, New Jersey, retrofit a system that totaled 160 tons at a total cost of $284,000 (Gahran 1994). The system included 32 heat pumps. The unit cost was $1,775/ton in 1993 dollars.

• Paint Lick Elementary School in Garrard County, Kentucky, designed the technology into the new school building. The system totaled 123 tons (433 kW) at a total cost of $380,010 (WaterFurnace WF666). The unit cost was $3,090/ton in 1992 dollars.

• Maywood Elementary School in Hammond, Indiana, designed the technology into a new school building. The unit totaled 250 tons (880 kW) at a total cost of $1,277,190 (WaterFurnace WF925). The system consisted of 74 heat pumps and a ground-coupling system consisting of 244 vertical wells. The unit cost was $5,110/ton in 1994 dollars.

• The Lincoln, Nebraska, school district installed ground-source heat pump systems in four new elementary schools. In each school, the system consisted of 54 heat pumps ranging in size from 1.4 tons to 15 tons, with a total cooling capacity of 180 tons (630 kW). Four gas-fired boilers with a capacity of 330,000 Btuh each provide hot water for preheat and terminal reheat. The total heat pump cost per school was approximately $657,000 ($3,650/ton) in 1995 dollars (Shonder et al. 1999).

• Kavanaugh (1995) concluded that the average cost of ground-source heat pumps (including unit, loop, duct, and installation) ranged from $2360/ton for a 5-ton horizontal loop to $3000/ton for a 3-ton vertical loop system. Compared to a 3-ton conventional system, the added cost was $1250 to $1550 per ton.

Installation costs are expected to drop as the ground-source heat pump industry infrastructure grows and designers and installers become more experienced. Reducing installation costs is one of the prime goals of the International Ground-Source Heat Pump Association and the Geothermal Heat Pump Consortium.

28.6.5 Other Impacts

There are no significant negative environmental impacts associated with ground-source heat pumps. There is, however, the potential for systems to be affected by some local codes and regulations. The most likely source of conflict, if any, lies with the installation of the ground-coupling system. Working with an experienced installer is the best advice. However, local electric utilities and other local sites with existing ground-source heat pump installations are other sources of information about local permit and regulation issues.

With the application of any electrotechnology, there is a potential environmental benefit. Installing a ground-source heat pump system in lieu of a fossil-fuel heating system will reduce local emissions. Furthermore, installing a more efficient electrotechnology such as a ground-source heat pump system for cooling will reduce source emissions at the utility power plant. Typical emission reductions per MWh of energy conserved are 0.3 pounds (0.14 kg) of particulates, 3.3 pounds (1.5 kg) of sulfur oxides, 5.3 pounds (2.4 kg) of nitrogen oxides, and 1,720 pounds (780 kg) of carbon dioxide. These numbers vary with time and region, depending on the power generation fuel mix (EPA 1994; Nemeth 1993).

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