Air Source Heat Pumps (Central Heating)

Air source heat pumps heat potable hot water and hot water for central heating. They do not normally have water storage. They are normally activated by a timer and/or a room thermostat plus the temperature to which water is heated by the air source heat pump is set by the ASHP. They heat water by converting electricity supplied by the grid and although they replace fossil fuel boilers in the home they place additional demand on the national grid (electricity).

The main advantage claimed for an air source heat pump is that when the temperature is 0 deg outside the heat pump converts electrical energy to heat energy in the ratio of perhaps 2 to 1. When the outside temperature is favourable the heat store/buffer tank can be filled.

The main disadvantage is that the the Coefficient Of Performance drops by 0.67 – 1.07 for every 10 degrees in temperature fall so at -10 deg C the COP could be 1.0. The lowest temperature recorded in London was -17.4 deg c 1981.

Without stored energy there is a severe risk that the demand on the grid would cause catastrophic failures and individual homes with heat pumps will be the worst affected. The UK is planning to maintain and build more gas power stations and to also reinforce the National Grid. £millions will be spent on new gas power stations, simply to deal with contingency planning for bad weather.

Adding a 1,000 litre water tank in the home, in a garage, in an outside shed, or even below ground, will allow off peak electricity to be stored. A 1,000 litre tank will store 50KW/hr of off peak power which is enough for 4 hours of central heating. At times when the COD is favourable the hot water can be stored in a well insulated heat store and further heated with an immersion heater to 75 degrees centigrade so as to last for several days. Heat from the heat store is only returned to the central heating system when the SP1 ShowerPowerBooster is activated.

The ShowerPowerBooster SP1 gives the perfect flow and pressure to integrate a central heating buffer tank with a Combination Boiler.