What Works with What?

Feb. 11, 2011 - PRLog -- As the Government gets firmly behind renewable energy with the confirmation of the Renewable Heat Incentive, it’s a good time to look at the different technologies available.

Renewable energy encompasses any technology that takes its energy from the natural resources of the sun, wind, tides and ground. ‘Renewable’ simply means that this energy, unlike fossil fuels, is self-replenishing. There is now a wide range of renewable products, from wind turbines and wave hubs to biomass boilers, heat pumps, solar thermal and photovoltaic.

Currently no single technology offers a complete solution, so the way to achieve the most energy efficient system is to integrate several technologies. Nu-Heat has been researching the different options available based around its range of products.

Most of the heating systems in our homes run at 70 - 80°C but heat pumps can work efficiently at temperatures as low as 35 - 45°C. Underfloor heating is an ideal partner for heat pumps as it works efficiently with low temperatures, although factors such as floor coverings have to be considered as this will influence the performance.  

Connecting a heat pump with radiators used to be impractical, as the reduction in flow temperature would require a standard radiator to be approximately 250% bigger than normal! However, new high-efficiency radiators (incorporating low energy fans that cut in if the temperature drops below a certain level) are a similar size to regular models giving a more realistic alternative. Using the same radiator type, underfloor heating downstairs can also be combined with radiators upstairs, although it’s important that the temperature of both elements is kept exactly the same to maintain the effectiveness of the heat pump.

For an even more efficient system, solar thermal can be added into the design to supply domestic hot water. For this, a hot water cylinder with solar coil will be needed. With different controls for the separate elements of such a system, it’s important that the controls work in harmony and are correctly programmed. It helps the supplier to know when heating and hot water is likely to be used and the estimated water usage for a property.  

A holiday cottage development in Awliscombe near Honiton is a good example of how an energy efficient system can be successfully installed. The conversion of two derelict barns into three contemporary holiday cottages utilises a combination of underfloor heating and air source heat pumps. The farm buildings were Grade II listed, so the way the internal space was used for the conversion was crucial, as the existing ‘footprint’ of the building couldn’t be expanded. The choice of underfloor heating removed the need for radiators, freeing up around 15% of the room space. System design indicated that heat pumps were viable and an 8kW air source heat pump linked to a cylinder (for the hot water requirements of each cottage) was specified. As air source heat pumps are located outdoors, even more practical use was made of the existing internal space. For this property, Nu-Heat’s heat pump calculations show that potentially the annual fuel consumption of the cottages could be reduced by around 50% against gas and 58% against oil – and even more as fossil fuel prices continue to rise. Before installing the system, Paul Pulman of Pulman’s Builders received specialist training at Nu-Heat’s Honiton based training centre.    

When thinking about renewable products and systems, it’s good to talk to local experts who can give advice about what will and won’t work. For example, a heat pump may not be the right product for a poorly insulated older property but solar thermal could be a suitable alternative. A reputable supplier will be able to put you in touch with an experienced renewables installer.

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Nu-Heat is the largest specialist supplier of warm water underfloor heating systems to the UK domestic market, delivering fully designed underfloor systems to housebuilders and installers nationwide.