Energy from the sun that is stored in the air that surrounds us can be used to heat your building efficiently and effectively via the use of air source heat pumps. The energy is gathered by blowing fresh air over something called an evaporator which either contains refrigerant or a glycol/brine mixture which is transferred to the heat pump unit. When this low grade heat energy warms the liquid refrigerant, inside the ASHP unit, it boils at very low temperatures and expands into a gas. This gas is then compressed in the unit and it gives up its high grade heat energy into the building’s heating system. As is does so this hot gas is cooled and condenses back into its liquid form and the whole cycle start again. Optimum performance depends on a variety of factors including the design of the evaporator, the sizing of the ASHP unit and the design of the heating distribution system. The evaporator design is important because ASHPs will gather ice at some point and will need to get rid of this via a “defrost cycle”. Some units on the market are reversed cooling units and for this reason tend to have less than optimum evaporator design with close fins making it easy for ice to gather. Sizing of ASHP units is especially important as the capacity tends to reduce at lower outdoor temperatures and there also needs to be a sufficient amount of energy available for teh defrost cycle. Lower temperature heating systems such as under-floor heating allow ASHPs to operate at a higher efficiency than traditional radiator systems. At JKN Renewables we take great pride in designing systems for optimum overall performance and for this reason we like to take the “whole system approach”. We also like to get involved in more complex ASHP systems where “free” cooling can be provided as a by-product of hot water production and where energy recovered from outgoing ventilation air is used to increase system performance. We are an independent provider of GSHPs from a range of high quality manufacturers such as NIBE, Thermia, Danfoss & Dimplex.