PDF Publication Title:
Text from PDF Page: 052
air/refrigerant temperature difference reducing the required heat exchanger area. For R410A, as the optimum discharge pressure is dropped by increasing the airflow rate, the air refrigerant temperature difference decreases and the required heat exchanger area increases. This is shown in Figure 4.23, which shows the effect of heat exchanger area on system COP. 4 3 2 1 Airflow Rate: R744: Solid R410A: Open 0.05 kg/s 0.15 kg/s 0.25 kg/s 0.35 kg/s 0.45 kg/s 0 0 2 4 6 8 10 12 Area (m2/kW cooling capacity) Figure 4.23 Effect of heat exchanger area on system cooling COP, 45oC outdoor cooling condition, 12oC evaporating temperature 4.6 Real cycle conclusions By specifying the isentropic compressor efficiency, the thermodynamic cycle can be specified with only an evaporating temperature, a condensing pressure and a refrigerant exit temperature from the gas cooler. Additionally, if heat transfer coefficient correlations are included then estimated can be made regarding the size of heat exchanger required for a given cycle efficiency. In cooling mode, the compression ratios and compressor efficiencies, of the two cycles are comparable. As a result, relative cycle efficiencies are the same as for the ideal cycle, and R410A shows a considerable advantage. If the air flow rates over the heat rejecting coil are matched at reasonable levels, however, then the efficiency advantage of the R410A cycle over R744 is reduced by nearly half. In heating mode, because of the lower compression ratios for R744, above supply air temperatures of about 40oC the efficiency of R744 is higher than the efficiency of R410A, approximately 10% higher at a supply air temperature of 60oC. For supply air temperatures below 40oC R410A has higher efficiency than R744, approximately 8% higher for a supply air temperature of 35oC. For systems with compressors sized such that the cooling capacity is equal, R744 has higher capacity in heating at low outdoor temperatures. In a typical application, 41 Cooling System COPPDF Image | Comparison of R744 and R410A
PDF Search Title:
Comparison of R744 and R410AOriginal File Name Searched:
CR039.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 |