Hi,

I bought a used portable air conditioner from eBay which was rated as 7500BTU cooling.

I have peasure the power input as 600W (comp and fans)

7500BTU means 2.2kW of heat being moved.

This should mean that 2.8kW of hot air gets blown out the back.

I have ran the system and found that given a 20C condensor air inlet, exit temperature is 35C giving a 15C temp rise.

I set up an experiment to check if 2.8kW of heat is coming out the back.

I ducted the air flow leaving the AC unit through some heaters and applied power unitll i got the same temperature rise (15C) then that will tell me what the power is.

I have done this and found that only 1.5kW was needed to warm the air leaving the condensor by the same ammount the condensor does.

Given that the input power was 600W, 600W of the 1.5kW was input, therefor i was only producing 700W of cold air as opposed to 2.2kW of cold air.

Does anybody know why the system would be operating at such a poor level or what the test criteria for domestic portable AC systems are?

Thanks,
Stuart