Does anyone know how COP relates to temperature rise.
COP is coefficient of performance, it's a dimensionless number but
will be dependent on temperature rise, so if the heat pump is capable
of moving heat from the low temperature reservoir to the higher
temperature dump then the COP for that temperature difference tells
you how much heat will be put in the dump for every unit of energy
used in the pump.
That is, if the
ground is 10C and a heat pumps is rated at COP 4, what temperature would the
heat pump recover? What would COP 3 produce at 10C?
You need to specify both the low temperature reservoir and the heat
dump temperatures.
So if the pump is rated at a COP of 3 with the lower reservoir at 10C
and a dump at 21C then for every kWhr of electricity put into the
device it will release 3 kWhrs into the higher temperature.
As the delta t between cold and hot increases the COP will fall,
ultimately to the point that the difference is to great fro the
refrigerant to work at.
I'd quite like to know the COP of a natural gas liquifying unit.
AJH