Difference between heat & temperature

Too many people don't know the difference between heat and temperature... Dr Robert Curtis included

Yesterday, reading a woefully inaccurate newspaper article, I complained to my long-suffering wife that too many people don't know the difference between heat and temperature. Today, reading PE, I found that their number includes Dr Robin Curtis (Letters, PE November 2010). Fortunately for her, my wife was out of earshot at the time.

Dr Curtis writes that it may be impossible to heat a poorly insulated building to 20ºC with a heat pump delivering a maximum temperature of 60ºC, "regardless of how many kilowatt hours of heat you deliver". Not so. Sufficient heat will always maintain the required building temperature, regardless of whether it is delivered at 50ºC, 60ºC or the 80ºC of conventional boiler systems.

What does need attention is the size and type of the radiators - a lower temperature difference between the heat source and the room requires more surface area to achieve the same heat transfer, so larger and/or higher performance radiators are essential. This is why retrofitting heat pumps to buildings with conventional radiators nearly always results in poor system performance.

A similar problem arises with condensing boilers. The condensing process requires a lower return temperature to the boiler to reap the full benefit. This again demands increased radiator surface area - underfloor heating is one solution.

Roger Richards