View Full Version : AMMONIA refrigerant

robbiedapict

04-09-2006, 04:58 PM

Hi,

I have a refrigerant related problem and I am hoping you can help me. The question is:

A vapour compression refrigerator with AMMONIA as refrigerant works between 2.908 bara and 12.37 bara. Temperature after isentropic compression is 82 degrees C and the condensate is undercooled by 8 degrees C in the condenser.

What is the COP (Coefficient of Performance) of the refrigerant?

Looking forward to the answer or any pointers you can give me...

Please help!

dwrefrigeration

12-11-2006, 10:40 PM

you will need to find out the Cooling Capacity and the input power for the system

lraja

13-11-2006, 02:33 AM

According to the definition, COP is the amount of output, cooling or heating, you get for each unit of energy you spend on a vapour compression system. For a cooling application,

COP = Cooling capacity (kw)/Power input to the system (kW).

The power input may include all the ancillaries such as fans if you are looking for a realistic value. Otherwise, it is just the power consumption of the compressor.

taz24

14-11-2006, 02:07 AM

Hi,

I have a refrigerant related problem and I am hoping you can help me. The question is:

A vapour compression refrigerator with AMMONIA as refrigerant works between 2.908 bara and 12.37 bara. Temperature after isentropic compression is 82 degrees C and the condensate is undercooled by 8 degrees C in the condenser.

What is the COP (Coefficient of Performance) of the refrigerant?

Looking forward to the answer or any pointers you can give me...

Please help!

Coolpack is your friend.

Go to

http://www.et.web.mek.dtu.dk/Index.html

and follow the links to coolpack down load.

You will find all the answers to your questions

by putting the info you have given into the graph. It will tell you the COP.

Cheers taz,

Paulajayne

14-11-2006, 04:06 PM

Robbie

This looks like a homework question - if we do it for you how will you learn?

If I am wrong then sorry, and there is plenty of advice above.

Paula

COP=RE divided by WD you do not need the refrigeration duty just a pressure enthalpy chart and a calculator

Ian

winfred.dela

19-11-2006, 10:52 PM

I have a refrigerant related problem and I am hoping you can help me. The question is:

A vapour compression refrigerator with AMMONIA as refrigerant works between 2.908 bara and 12.37 bara. Temperature after isentropic compression is 82 degrees C and the condensate is undercooled by 8 degrees C in the condenser.

What is the COP (Coefficient of Performance) of the refrigerant?

Hi robbiedapict,

Why do you need the COP? For what purpose?

Any refrigeration book could have answered your question.

Paulajayne:

This looks like a homework question - if we do it for you how will you learn?

Will you please answer the above question . . . :rolleyes:

Regards,

Winfredy :)

I get it to 5.47 but surely you should have some suction superheat at the compressor which will change the COP a little

Ian

TXiceman

21-11-2006, 03:27 AM

Just read the text book and it will tell you exactly what the COP is defined as. Calculations are pretty straight forward. I agree that it sounds like a homework question.

Ken

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