Economic feasibility of ground source heat pump system deployed in expressway service area

Abstract

In an attempt to mitigate the reliance on fossil fuels as main power sources for expressway service areas in South Korea, a ground sourced heat pump (GSHP) is explored as an alternative power source, especially for high-oil-consuming service areas, and its economic feasibility is evaluated using three investment financing metrics: Payback Period, Net Present Value (NPV) and Internal Rate of Return (IRR). Fuel consumption and energy load data collected from 174 (out of 197) expressway service areas are analyzed to characterize their energy profile, and along with the energy per unit price, 20 simulation targets (service areas) with high oil consumption are selected to maximize the potential benefits of the GSHP system. Rather than a conventional peak load design concept, a base load (an energy load corresponding to 65% of total annual energy) is introduced for an optimal system design and operation. A pilot test building is constructed to verify the coefficient of performance (COP) of a GSHP system applicable to the target service areas. The results show that the payback period of GSHP systems is less than three years, regardless of energy loads and deployment options (new and retrofit). In addition, positive net present values and higher internal return rates suggest the proposed GSHP systems should be a viable option to save operation costs while maintaining higher energy efficiency. Finally, the potential greenhouse gas reductions of GSHP systems relative to oil furnace/air conditioning systems are calculated over the selected service areas.