Heat Pump.

The biggest design problem is the way that people think they can just replace the gas boiler and get any reasonable efficiency. The coefficient of performance (COP) of a heat pump is directly related to the temperature difference across the pump, in the same way as water and a water pump. More head takes more power in pretty much direct relation as more work is done. If the temperature difference is small the COP can be quite large, perhaps as much as 10 for a fridge on a cold day in the kitchen, but the freezer in the same conditions will get 3-4. Air exchange heat pumps have another problem when the temperature is somewhere close to zero, and that is that the evaporator (the outdoor bit gaining heat) may well freeze up with ice and block ait flow, just like the fridge but worse because of the high air flow.

It is being suggested that radiators may be used with water at 50-60C. This is mad as we only need to heat the air to 20C, so why not heat it directly which will give a much better COP as the condenser temperature needs to be little more than 20C to work. Such systems are in common use in offices and commercial premises. Thus we exchange a temperature difference of 60C for 30C and the COP will approximately double. Surely these “fine minds” planning the Green revolution know just a little science?

Actually, I am sure they know none whatsoever, and if they did this Climate and Green nonsense would have stopped dead in its tracks. Clearly, the IET editorial team does not either, as the latest E&T shows, it is simply regurgitated press releases from the COP26 mob. Why an Engineering Institution has so little science and engineering knowledge is completely beyond me. The most interesting point is that they don't want to listen and learn either!

The biggest design problem is the way that people think they can just replace the gas boiler and get any reasonable efficiency. The coefficient of performance (COP) of a heat pump is directly related to the temperature difference across the pump, in the same way as water and a water pump. More head takes more power in pretty much direct relation as more work is done. If the temperature difference is small the COP can be quite large, perhaps as much as 10 for a fridge on a cold day in the kitchen, but the freezer in the same conditions will get 3-4. Air exchange heat pumps have another problem when the temperature is somewhere close to zero, and that is that the evaporator (the outdoor bit gaining heat) may well freeze up with ice and block ait flow, just like the fridge but worse because of the high air flow.

It is being suggested that radiators may be used with water at 50-60C. This is mad as we only need to heat the air to 20C, so why not heat it directly which will give a much better COP as the condenser temperature needs to be little more than 20C to work. Such systems are in common use in offices and commercial premises. Thus we exchange a temperature difference of 60C for 30C and the COP will approximately double. Surely these “fine minds” planning the Green revolution know just a little science?

Actually, I am sure they know none whatsoever, and if they did this Climate and Green nonsense would have stopped dead in its tracks. Clearly, the IET editorial team does not either, as the latest E&T shows, it is simply regurgitated press releases from the COP26 mob. Why an Engineering Institution has so little science and engineering knowledge is completely beyond me. The most interesting point is that they don't want to listen and learn either!