Description and Operation:
A heat pump is classified according to the source from which it extracts heat, i.e. the low temperature heat source. One that collects and utilises thermal energy from the outside air to heat the home and provide domestic hot water is called an air source heat pump.
In an air source heat pump, outdoor air is drawn into the heat exchanger, which contains coils filled with a pressurised refrigerant gas. The refrigerant gas referred to here is a chemical compound that circulates around a closed loop passing through all major components of the heat pump. Next the gas which is in vapour form is compressed to raise its temperature, before it is passed through a second heat exchanger which removes the heat and uses it in the heating system to provide space heating and hot water. Essentially it acts like a fridge in reverse.
Key Performance Parameters:
* Available output range: 4kW – 17kW
* Operating range (outdoor): -20oC – 45oC
* Provide water temperature of between 55°C - 60°C for domestic hot water applications. * Typical space heating between 35°C and 55°C.
* Designed to operate efficiently with radiators or under floor heating systems. * “Advertised” figures for coefficient of performance (COP) of 3-4 implying an efficiency of 300% - 400%, i.e. 1kW electricity in and 4kW heat out. * Compressor operates from 20% load to 120% load, fully modulating.
Information required by DEAP:
When calculating the BER of a domestic dwelling in evaluating its overall performance, DEAP requires information on whether the air source heat pump is required to deliver interior space heating or domestic water heating (DWH). On this basis, there are two options for accounting for this in DEAP with regard to the efficiency (also called Seasonal Performance Factor or SPF):
* If the air source heat pump is not supplemented by a separate water heating immersion for DHW and can therefore provide...