| Abstract: | Some methods are discussed for detecting the formation of ice on the evaporators of air-source heat pumps and air coolers by electronic means. the sensing of thermal resistance caused by ice build-up can be done by measuring temperature differences between the evaporator and the air, and analyses are presented of the effect of using both linear and non-linear temperature sensors for this purpose. the direct detection of the presence of ice can be done by measuring the capacitance of a suitably-placed pair of plates, and the performance of such a system is analysed. Preliminary reports are presented of the use of both of these methods of ice detection in the defrosting of an experimental heat pump. |
