Cooling capacity and energy useage!

Hi, can someone please explain why when the evaporating temperature is increased by 1degC the energy usage DECREASES by 3%. I understand that the cooling capacity increases by 3%, because the evaporator fills with more liquid as the txv maintains the S/H. In my ignorance the energy usage would be more as the temperatures increase and the condenser fan runs at say full speed.
A little confused
Thanks

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why when the evaporating temperature is increased by 1degC the energy usage DECREASES by 3%

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Not DECREASES, but INCREASES - if by that condensing temp is kept unchanged. This means mass flow increases, therefore power consumption rises.

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Originally Posted by Burrah Boy

Hi, can someone please explain why when the evaporating temperature is increased by 1degC the energy usage DECREASES by 3%. I understand that the cooling capacity increases by 3%, because the evaporator fills with more liquid as the txv maintains the S/H. In my ignorance the energy usage would be more as the temperatures increase and the condenser fan runs at say full speed.
A little confused
Thanks

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You are confusing yourself with the terminology. It uses a little more energy as it runs, but shuts off a lot sooner. It is 3% more energy efficient.

Its not the bang and its not the buck. Its the bang for the buck.

Thanks, it was just one of the questions they ask on the F-Gas practice question paper in the UK. Thanks for the help. Sometimes I wonder just WHO actually sets some of these questions as I sometimes question their answers!

Your COP increases

Your energy useage decreases due to your suction pressure increasing and the compressor taking less energy to get the pressure up. The gas flow goes down so the condenser has less to do.