It’s often stated that heat pumps can only be used where under floor heating is specified. Whilst it’s true that heat pumps work very effectively with under floor heating this isn’t the only method of heat distribution that can be used. Most common forms of heating and cooling system can be integrated with a heat pump.
- Under floor heating: The main advantage of wet under floor heating is that the flow temperatures required are relatively low. Most buildings can be effectively heated using flow temperatures as low as 25-35°C. This is particularly true of new buildings with high levels of insulation and low heat losses. This enables the heat pump system to run at maximum efficiency. It is usually more of a challenge to retrofit under floor heating in older buildings but this approach can work. Under floor heating should be carefully specified if it is intended to be run with a heat pump. Pipe spacing and controls are important factors for example. Under floor heating can also be used to provide passive cooling in buildings. This can be a low cost, invisible and silent alternative to conventional air conditioning systems.
- Radiators: Conventional radiator systems are usually specified to run with flow temperatures in the 65-75°C range. This is the norm when running with a gas boiler. When a heat pump is being used we try to limit the maximum flow temperature to around 45°C to maximise efficiency. To run at this temperature radiators need to be larger than would normally be the case. Most radiator manufacturers now give the outputs of their products at a wider range of flow temperatures so that they can be accurately specified to run with a heat pump. In addition there are special, fan-assisted radiators designed to work specifically with heat pump systems. These products, from manufacturers like Jaga offer an excellent alternative to under floor heating in new build and retrofit projects. Some of these products can also be used for cooling purposes.
- Fan coil and AHU systems: In many commercial buildings fan coils and AHU’s are used to distribute heating and cooling. Again these can be specified to run with the lower flow temperatures associated with heat pumps.
- Simultaneous heating and cooling: In some cases there’s a need to offer the capability for simultaneous heating and cooling, in office buildings for example. Many heat pump systems can do this very effectively, with 100% heat recovery. Distribution using 4-pipe, ceiling mounted cassette style units can be a good alternative to conventional VRF systems. Using a water based distribution system saves the need for compliance to the F-Gas regulations which are becoming increasingly onerous for building owners.
- Hybrid systems: We often specify systems where the heat pump is only providing part of the overall heating load. Heat pumps are regularly combined with gas boilers or even biomass systems in some cases. Careful consideration needs to be given to the interface between the two systems and the flow temperatures that are being used. We can also advise on integration of heat pumps with conventional chillers and coolers where cooling is needed.
- District or communal heating: In these systems a single heating or cooling system is linked to multiple buildings or, in the case of apartment buildings, to multiple individual flats. We can advise on the options for communal or district schemes.