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How to find tonnage or KW, EER of refrigerator

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michealmassa

Mechanical
Apr 5, 2016
1
Why do refrigerators doesnt quote the rating in tons . How to calculate the EER and Tons from the data available on the plate attached to refrigeraor.
IMG_20160405_104657_mr2wjh.jpg
 
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You should call the manufacturer and ask him this question.

Failing that, ask a senior person in your office.
 
The information is likely not listed because it is not required to be listed by Indian law.

From the information on your picture it is not possible to calculate the capacity.
 
The volume is simply the volume of the refrigerator and is not specifically related to the cooling capacity. All the volume tells you is that this is one of those college dorm or under-the-counter refrigerators.

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faq731-376 forum1529
 
Cooling capacity for a refrigerator is really not a necessary piece of information to the buyer. All the buyer needs is the climate class that matches their usage climate, and they'll know that the refrigerator will keep food cold and the freezer will freeze food. An air conditioner is different, because the buyer needs to know how big a room or house they can cool, using rules of thumb like 1 ton per 700 sq.ft. of living space.

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faq731-376 forum1529
 
If you can make a rough estimate of the COP of this refrig cycle for R134a, then it should be possible to get some idea of the refrig capacity. R134a is stated to be similar to R12 in refrigeration behavior.

For example, if COP is approx 2.5 for an air cooled condensor condensing at 100degF, evaporating at -30degF, then refrig capacity, peak would be 105 x 2.5 = 263W = 897Btu/hr = 0.075tons refrig capacity

While refrig capacity, normal, continous, assuming the compressor runs for say 30% of the time = 263 x 0.3 = 79W = 269Btu/hr = 0.022tons refrig capacity

COP would of course be better in winter and lower in hot weather. Net cooling capacity would also depend on insulation from ambient heat leak into the fridge.

1 ton of refrigeration capacity = 12000Btu/hr

COP = Net refrig effect (sat vap enthalpy - sat liquid enthalpy, Btu/lb)/ heat of compression, Btu/lb



 
The trial value of 2.5 for the COP is taken from table 12-7 in Perry Chem Eng handbook 6th edition for R-12 operating at 100degF condensing, -30degF evaporating intervals, which possibly approximates the operating conditions in this refrigerator. These tabulated values assume the application of a compressor suction HX, but this doesnt alter the COP much.
 
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