18-2 The heat pump and structure whose characteristics are shown in Fig. 18-6 are in a region where the design outdoor temperature is -15°C. The compressor of the heat pump uses two cylinders to carry the base load and brings a third into service when needed. The third cylinder has a capacity equal to either of the other cylinders. How much supplementary resistance heat must be available at an outdoor temperature of -15°C? Ans. 5.8 kW. Energy flow rate, kW 24 22 20 18 16 14 12 10 8 00 T New balance point -20 Balance point -10 Additional capacity Heat loss of structure 10 Outdoor-air temperature, "C Figure 18-6 Balance points of heating capacity and heating load. Heating capacity 20

18-2 The heat pump and structure whose characteristics are shown in Fig. 18-6 are in a region where the design outdoor temperature is -15°C. The compressor of the heat pump uses two cylinders to carry the base load and brings a third into service when needed. The third cylinder has a capacity equal to either of the other cylinders. How much supplementary resistance heat must be available at an outdoor temperature of -15°C? Ans. 5.8 kW. Energy flow rate, kW 24 22 20 18 16 14 12 10 8 00 T New balance point -20 Balance point -10 Additional capacity Heat loss of structure 10 Outdoor-air temperature, "C Figure 18-6 Balance points of heating capacity and heating load. Heating capacity 20

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter48: Cooling Towers And Pumps

Section: Chapter Questions

Problem 13RQ

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6-11 A refrigeration plant that operates on the cycle shown in Fig. 6-23 serves as a water chiller. Data on the indivldual components are as follows: 30,600 W/K evaporator condenser (6.8 kg/s 7.6 kg/s evaporator condenser UA = Rate of water flow = | 26,500 W/K The refrigeration capacity of the compressor as a function of the evaporating and condensing temperatures & e and 1C, respectively, is given by the equation developed in Prob. 4-9 de, kW = 239.5 + 10.073te - 0.1091 - 3.41te - 0.00250 - 0.2030fc + 0.00820te + 0.0013fef -0.00008000st2r2 The compression power is expressed by the equation P, kW = -2.634- 0.3081te - 0.00301/ + 1.066f- 0.005281 - 0.0011lete - 0.00030612t, + 0.000567tet + 0.0000031r21 The condenser must reject the energy added in both the evaporator and the compressor. Determine the values of te, le, le, and P for the following combinations of inlet water Condenser Compressor Evaporator Expansion valve