Ground Breaking Technology for Super Energy Efficient Home
ECO-FRIENDLY TIMBER FRAMED HOME
This stunning, Oakwrights property built recently in the heart of Berkshire Downs may look traditional from the outside, but inside it is anything but.
It houses a state of the art heat recovery and ventilation system which the distributors Starkey Systems have specified to replace trickle vents and extractor fans.
Energy savings are gained with the use of a 95% efficient heat exchanger that will recover heat from the extracted air of the property and transfer it to the fresh filtered incoming air. In essence, the property will benefit by having a constant supply of fresh air without the heat loss associated with traditional cold drafts from trickle vents and extractor fans.
The five bedroomed 557m² property has been crafted to an exacting specification for businessman Darren Rayner and his family. Mr Rayner who has also overseen the entire project, specifically chose products that would help deliver the most energy efficient solutions. Unlike most Eco builds however, it is built around a traditional oak framed constructed by Oakwrights of Hereford and has all the style and features that you would expect from an English period property. Quite simply it is a brilliant combination of state of the art building technology and family home comforts.
Darren Rayner’s objective to build his house in a traditional style with contemporary, energy efficient technologies has been achieved very successfully.
The property has a ground source heat pump which extracts energy from the earth to power an under-floor heating system and a ground – air heat exchanger system which provides a constant supply of fresh air.
GROUND AIR HEAT EXCHANGER
The ground – air heat exchanger is a new system in the UK from polymer specialists REHAU which is branded AWADUKT Thermo. It works on the principal that at just 1.5m below ground, the earth is a fairly constant 8-12ºC. A run of polypropylene pipes is simply laid at 1.5m depth and, as air is drawn in through the pipes, heat transfer takes place either cooling the incoming ventilation air in summer or warming it in winter.
The system can reduce the temperature of the air by as much as 14ºC in summer and increase it by as much as 9ºC in winter. This not only produces a more comfortable internal environment but promises to deliver annual energy savings of around 1,500kWh/a for heating and 700kWh/a for cooling.
At the Rayners’ property, Starkey Systems has laid two 40m runs of 200mm polypropylene pipe work and sited the air inlet tower discreetly out of sight. Each of the pipe runs is combined with a separate heat recovery unit located in the basement which increases the overall heat recovery efficiency and also allows the air to be delivered into the property via smaller 100mm diameter pipe sizes. A summer bypass provides the cooling solution in summer offering an energy efficient alternative to air conditioning.
Starkey Systems use specific software to calculate the energy performance of the system. The length of pipe work required is based on the soil conditions, the airflow of the ventilation system and the geographical location.
Rigid ducts and pipe work are used to deliver the air into the house and 3D CAD drawings map the internal pipe runs to the nearest millimetre so that the pipes are accommodated easily within the building without any ugly boxing.
The AWADUKT Thermo system has been brought to the UK by REHAU, which is one of the world’s leading producers of polymer pipe work. It is used extensively across Europe and in the UK is already popular in commercial applications, particularly as part of the Building Schools for the Future programme.
Although based on the simple principle of using the earth’s natural heat to pre warm or pre cool incoming air, it is actually very advanced polymer technology which enables the system to operate successfully.
For example, the polypropylene used for the pipe work is optimised to enable the maximum heat transfer to take place and a patented silver antimicrobial layer incorporated into the inside of the pipe ensures there is no microbial growth in the pipe itself which could cause musty smells. A condensation collection chamber is also sited under the ground so that there is no build up of water within the system.
The Coefficient of Performance of REHAU AWADUKT Thermo is hard to beat in the domestic environment. Typically, it is between 50 and 100 (ie 50 – 100 units of energy are delivered for every 1 unit of energy consumed) which compares very favourably with a Coefficient of Performance of between 3 and 4 for a ground source heat pump.
REHAU has identified the domestic market as a key growth area for AWADUKT Thermo and has linked with specialist installation companies like Starkey Systems to help to deliver the system into the oak frame self-build and specialist eco homes sector.