How efficient is a refrigerator compressor?
The reciprocating hermetic compressors are those most commonly found, especially in refrigerator and freezer type applications. As shown in table 3 the compressor efficiency is approximately 50 % of the Ideal cycle with ∆T.
How do you calculate Exergy efficiency of a refrigerator?
The refrigerant mass flow rate is constant through the cycle and denotes as ˙m in kg/s, h is the specific enthalpy of each state point in kJ/kg, exi is the specific exergy of a state point in kJ/kg and defined as exi=(hi−h0)−T0(si−s0) , and s is the specific entropy of the refrigerant at each state point, and its unit …
How is refrigerator efficiency calculated?
The coefficient of performance of the fridge is the refrigerating effect per cycle, Q1, divided by the net work done on the fridge per cycle, and, for a Carnot cycle it can be calculated from T1/(T2 − T1).
How do you calculate Exergy efficiency?
(EEF) of Complex Systems 1988) that the exergy efficiency of the system on the whole can be calculated as the ratio of total useful exergy effect of the system (product) to available exergy (fuel).
What is the efficiency of a fridge?
When selecting a refrigerator, remember the following: Refrigerators with the freezer on either the bottom or top are the most efficient. Bottom freezer models use approximately 16 percent less energy than side-by-side models and top freezer models use about 13 percent less than side-by-side.
What is the efficiency of refrigerator?
Refrigerators can use 2.5 percent more energy for each 1 degree over normal ambient room temperature (70 degrees). This means your refrigerator could use 22 to 25 percent more energy in an 80-degree room, and 45 to 50 percent more in a 90 degree room.
How do you increase exergetic efficiency?
Based on your exergy analysis, find the most destructive component. Then carry out the parametric study of design parameters of destructive components to identify the most sensitive component. This can leads to improvement of the system by improving the component performance.
Is exergy efficiency higher than energy efficiency?
So the input exergy is a fraction of input energy. Therefore, the exergy efficiency is higher than the energy efficiency.
How is the exergetic efficiency of an evaporator determined?
Furthermore, the highest exergetic efficiency is obtained by a decrease in the temperature of the secondary fluid inside the evaporator, and by an operation of the compressor at low speed. The efficiency of the compressor is also included in the analysis, which is a parameter that determines the exergy destruction of the largest component.
When to use a vapour compression refrigeration system?
Commonly, simple vapour compression refrigeration systems are used for comfort cooling and cold storage application. Depending upon the applications evaporating temperature varies from –50 °C to 7 °C (Bilal and Syed, 2011). The scientists investigate more environmentally friendly refrigerants to resolve the problems of ODP and GWP.
Where does exergy destruction occur in a refrigeration system?
Thus, the results show that most exergy destruction is located in the condenser, followed by the compressor, the expansion valve and the evaporator. Furthermore, the highest exergetic efficiency is obtained by a decrease in the temperature of the secondary fluid inside the evaporator, and by an operation of the compressor at low speed.
Which is better for vapour compression R134a or r410c?
Considering the first set of refrigerants R134a, R410A and R407C while second set include the refrigerants of R717, R404A and R290. From a first law standpoint, the COP of R134a always performs better than R410A and R407C unless only the evaporator is being fouled.