PDF Publication Title:
Text from PDF Page: 292
Appendix A – CO2 as a Working Fluid in Heat Pumps At 8.5 MPa high-side pressure, there is a pinch point inside the gas cooler (∆Tm), which leads to a high CO2 outlet temperature from the gas cooler. Despite the moderate input power to the compressor, the COP will be relatively low due to the limited heating capacity of the heat pump. By increasing the high-side pressure to 10 MPa, the CO2 isobar becomes more linear, and the outlet temperature from the compressor increases. Due to the improved temperature fit between the fluids, there is no pinch inside the gas cooler that hampers the heat transfer process, and the mini- mum temperature difference ∆Tm is now identical to the temperature app- roach ∆TA at the hot outlet of the gas cooler. Since the marginal increase in the heating capacity is considerably larger than the marginal increase in the power input to the compressor, the COP increases. At 11 MPa high-side pressure, there is only a marginal change in the heating capacity of the heat pump, and due to the relatively larger increase in the input power to the compressor, the COP is lower than at 10 MPa. Consequently, 10 MPa is the optimum high-side pressure that leads to a maximum COP for the CO2 heat pump water heater at the actual operating conditions (5/70oC). Heat Transfer Coefficients The thermophysical properties of CO2 exhibit large variations at super- critical pressures (ref. Section A1.6), which will affect the local heat transfer coefficients in the gas cooler. Due to this fact, variations in the high-side pressure influences the heat transfer process and consequently the CO2 outlet temperature from the gas cooler. A22PDF Image | Residential CO2 Heat Pump System for Combined
PDF Search Title:
Residential CO2 Heat Pump System for CombinedOriginal File Name Searched:
20559406.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |