Energy, economic and environmental evaluation of a novel combined cooling and power system characterized by temperature and humidity independent control

摘要

A novel combined cooling and power system with independent control of temperature and humidity was presented to meet the energy supply demand in buildings. The energy, economic and environmental characteristics of the organic Rankine cycle powered two-stage vapor compression cycle with sixteen organic working fluids were discussed at variable geothermal fluid temperature. The results showed that organic Rankine cycle powered two-stage vapor compression cycle had certain advantages in improving refrigeration performance. Taking the critical mass flow rate as the boundary, the cooling and electricity output of the system could be controlled by adjusting the mass flow rate of refrigeration device. As far as the output power of the system was concerned, R1234yf, R134a, R600a, R600, R123 and R601 were suitable for different temperature ranges of geothermal fluids, while in terms of refrigeration performance, R1234ze, R245fa, R123, and R601 were respectively suitable for different geothermal fluid temperatures. The system with N-heptane had the optimal techno-economic performance, which electricity production cost decreases from 0.1543 $/kWh to 0.0484 $/kWh. Therefore, the novel combined cooling and power system can meet the seasonal cooling and electricity demand of the building and maximize the use of dry hot rock resources.