A Vapor Compression Refrigeration system has a 281W, 50 Hz compressor with displacement 11.1 cm3/rev. 50 Hz compressor has RPM 3000. The discharge pressure is 13.5 bar, the suction pressure is 0.13 bar. Subcooled liquid temperature is 32°C, superheated temp is 54.4°C and evaporator temp is -23.3°C. Thus, the mass flow rate can be calculated to be 2.2 kg/min. That gives heat removed from the evaporator as 254kJ/min. Thus, to cool a load of 100 kJ, it takes only 23 sec? But in reality, it takes somewhere around 1 hr to cool the object with a 100 kJ load. How to approach this problem?
The time required to cool the midsection of the product is determined from transient temperature charts
First, the heat removed you mentioned above is for steady state condition analysis. Second, your calculation is probably ideal condition. Let's assume your refrigeration system is already ideal condition.
Then, is your 100 kJ load your experiment? if yes, is it perfectly thermal insulated?
In real world, there always small heat loss when you use insulation material. So you need to consider this heat loss. How? The simple way is to analyze the transient temperature increasing when your object is cold and without cooling system (your refrigeration system is off).
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