The refrigerator in your kitchen works according to the diag

The refrigerator in your kitchen works according to the diagram. The working fluid for this refrigerator is R134a (Refrigerant 134a, i.e., 1, 1, 1, 2-tetrafluoroethane). You know that the temperature of R134a is +55 degree C at point 1 and -20 degree C at point 3. The refrigeration cycle only runs when necessary, but when it does, you may assume that it operates at steady-state. Unless specified, assume an ideal cycle and operation of the equipment at maximum efficiency. Sketch a P versus H diagram for this cycle. Indicate the phases of the refrigerant and the direction of the cycle with arrows. Do not worry about numeric values in this diagram. Since the refrigerator is operating at maximum efficiency, there are many constant quantities across several of the paths in this cycle. For each path, specify which, if any, quantities are constant and specify the fluid state of the working fluid (e.g., saturated liquid, etc.). You need only consider entropy, enthalpy, temperature, and pressure for each step. What is the heat removal of the evaporator per mass of refrigerant? What is the work of the compressor per mass of refrigerant? or using the P-H diagram included at the end of this problem.) The refrigerant compressor operates at one speed, 0.20 kg/min. If the average daily heat removal requirement for your fridge is 12,000 kj, approximately how many hours per day does the compressor have to run? It is common for dust to build up on the condenser coils of a household refrigerator (it is recommended that you clean these coils twice per year)! In your apartment, the condenser coils have never been cleaned, and as a result, the heat transfer across the coils is reduced by 45%. Sketch the changes you would see on the same P-H diagram you made in part a. Recalculate the hours that your compressor has to run per day. How might this affect your life and the lifespan of the fridge?

Solution

The answer of the following questions are as follows

d) The compressor have to run 22 hours per day approximately.

e) The compressor has to run 17 hours per day.The life of the fridge is decreased and the lifespan too.