Question

Please answer all the parts if possible. There are some repeated questions, you can just write down some key points. If just answered some parts that's ok.

Refrigeration Cycle Analysis In the refrigeration lab, a water bath is cooled to sub-ambient temperatures by using a refrigeration unit and a heater at the same time. The refrigerant used is R-290 (propane), with a density of 0.5 kg/L. The sight glass for measuring the refrigerant flow rate has a volume of 14 ml. Using the propane property table and the data recorded in Table 3, answer the following questions. Table 3 Refrigeration Lab Data Reporting Pressure [kPa] Temperature [C Compressor Heater Refrigerant [kW] 0.270.3 7.18 0.27 038 S,137 Water Bath Evaporator Condenser Ev Temp InOIn Out gauge absolute gauge absoluteIKW] Evaporator Condenser Power PowerFlow Time 9662 21 60 5°C o70 (200 270 10 C Water bath temperature at 10°C Consider an ideal refrigeration cycle 1. Draw the T-s diagram, and use the two measured pressures to calculate the COP of the ideal cycle Consider an actual refrigeration cycle 2. 3. 4. 5. Draw the T-s diagram and mark all measured temperatures except the one at the evaporator inlet. For this actual cycle, zero pressure loss is assumed in the condenser Consider the expansion process as isenthaipic, calculate the entropy at the evaporator inlet. Mark the temperature on the T-s diagram. Using the T-s diagrams drawn in part 1 and 3, discuss the major differences between the actual cycle and ideal cycle Calculate the COP of the actual cycle. Conduct an energy balance on the water bath. Discuss if it is reasonable to assume that the bath is well insulated 6. ater bath temperature at 5°C an 7. 8. d 15°C Calculate the COP at both temperatures using the above actual cycle analysis. Mark the measured pressures and temperatures on the T-s diagram. Discuss how in theory the COP should vary with the water bath temperatures from 5°C to 15°C. Are your results consistent with the theory? If not, discuss the potential causes.

Answer 1

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8:00 PM Saturation Temperature Table (PC Model) of Propane (C3H8) Spec. Int. Energy Temp. Sat. Press Spec. Volume Spec. Enthalpy Spec. Entropy ul ul ul LU 85.5 1.65x 10 00 2.52 120 2.95x 10 40 7.87 x 1020.001475 3.354 x 10 -389.60 60 8.47 x 10 0.001364 9.570 x 10 0.001392 7.470 x 10 0.001432 7.660 x 103 495.72 -467.82 -428.94 1.8813 2.1826 2.5370 2.8402 3.1067 8.4639 7.6624 6.9421 6.4837 6.1824 5.9814 5.8468 5.7573 5.7219 5.6989 5.6619 5.6391 5.6242 5.6106 5.5884 5.5293 5 3376 50.78 495.72 61.30 467.82 77.05 -428.94 94.10 -389.60 349.68 66.90 x 10 120.49 142.44 165.35 188.92 212.83 0.001521 3.558 x 10 112.31 3.3465 3.5665 3.7719 3.8808 3.9668 0.00157 6.69013 1.84938 0.66753 101.30.00172 0.41342 147.9 0.001752 0.29076 0.14475 581.5 0.001925 0.07919 997.4 0.002043 0.04618 0.0022 0.02793 0.01693 554.0 0.002894 0.00949 -308.95 31.56 -308.95 -267.14 223.95 84.18 199.33 93.72 -179.01 -131.88 -82.05 20.1 0.001624 60.5 0.001684 151.68 172.47 -224.06 231.1 179.27 -132.45 -83.17 30.84 25.38 310.5 0.001831 215.19 4.1542 4.3369 4.5176 4.6996 4.8883 282.57 1598.4 2430.6 0.002433 275.78 290.00 320.42 0.016 93.09 170.69 24.79 5.1013 269 9 4247 7 0 004535 0 0045 240 34 240 34 259 61 259 61 5 3376