Unformatted text preview: cycle COP? 3. (11.129) A small heat pump unit is used to heat water for a hot-water supply. Assume that the unit uses R-22 and operates on the ideal refrigeration cycle. The evaporator temperature is 15 °C, and the condenser temperature is 60 °C. If the amount of hot water needed is 0.1 kg/s, determine the amount of energy saved by using the heat pump instead of directly heating the water from 15 to 60 °C. 4. (11.133) In an actual refrigeration cycle using R-12 as the working fluid, the refrigerant flow rate is 0.05 kg/s. Vapor enters the compressor at 150 kPa and -10 °C and leaves at 1.2 MPa and 75 °C. The power input to the nonadiabatic compressor is measured and found to be 2.4 kW. The refrigerator enters the expansion valve at 1.15 MPa and 40 °C and leaves the evaporator at 175 kPa and -15 °C. Determine the entropy generation in the compression process, the refrigeration capacity, and the coefficient of performance for this cycle....
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- Summer '09
- Heat Pump, °C, Gas compressor, 2.4 kW