Combining Ground Source Heat Pump and Organic Rankine Cyle for Power and Heat

Abstract

This study is conducted to analyze the working of borehole thermal energy storage (BTES) with ground source heat pump (GSHP) and organic Rankine cycle (ORC). Drake Landing Solar Community (DLSC) situated in Okotoks, Alberta, Canada with 144 boreholes generating 236 kW of the heating load is taken as a case study to investigate its functionality when coupling with GSHP and ORC. Nine different refrigerants falling in the desired temperature range when BTES temperature drops to 60°C or 50°C during the winter season. This work is an effort to make the existing heating system into a combined heat and power (CHP) system, which is able to generate power to run the BTES and district loop pumps and also provides the heating at the same time. Results revealed that, at a source temperature of 50°C from the BTES, the combination of refrigerant R1234YF-R1234YF was considered to be the best at 75°C evaporation temperature; it raised the fluid temperature at the condenser to 83°C by having maximum coefficient of performance of 3.5 of GSHP and overall combined heat and power efficiency of 77%.