Mitsubishi Electric has some timely advice for anyone whose building does not currently incorporate heat recovery equipment as part of their heating and cooling system. Jason Tinsley explains
WE are all under pressure to save energy. As a manufacturer of energy-consuming heating and cooling equipment, Mitusbishi is trying to help customers reduce their energy use under its Green Gateway initiative, which aims for UK reductions of more than 3Mtonnes of CO2 per year by 2012.

One of the central ideas is combining as much free cooling as possible with the recovery of wasted heat. This will keep the level of energy a building consumes to a minimum, and ensure the occupants have a comfortable environment.

It is good business to keep your outgoings to a minimum. If you can cut your building's energy consumption - and therefore your energy bills - not only will you earn the praise of Al Gore and the green lobby, your finance director is sure to be impressed too.

Life does not make things easy though. Part F of the Building Regulations insists on appropriate levels of fresh air. But it seems to contradict Part L, which aims to cut energy wastage and stop heated or cooled air being thrown away.

So, just how can you balance the need to keep as much heating or cooling energy inside your building, while ensuring you can provide a fresh and healthy working environment? Thankfully, help is available in the form of heat-recovery ventilators that allow you to extract and replace stale air while recovering the energy.

This energy is then used to treat the incoming fresh air to reduce the overall energy consumption, thereby helping comply with both Part L and the new air tightness of buildings regulations and Part F ventilation requirements.

When the outdoor temperature is lower than the indoor air conditioned temperature in the summer, these units can also provide fresh outdoor cool air to reduce the indoor air temperature. This effectively provides free cooling - minimising the amount of mechanical cooling required, and therefore the energy consumed.

Systems such the Lossnay air-to-air heat recovery systems have all received Enhanced Capital Allowance approval because of their energy efficiency.

Equipment qualifying under this scheme allows customers to claim tax relief on the products and offset some of the capital investment against their annual tax bill. So, not only are you reducing energy use and your monthly bills, you can also lower the level of tax you face.
At the heart of the heat recovery system is a special core of ultra-thin film. This separates the incoming fresh air and outgoing stale air but allows the energy to transfer from one to the other.

This energy is transferred through the cross-flow, plate-fin structure of the diaphragm to keep supply and exhaust air separate but maximise the efficient transfer of heat.

This diaphragm is made of specially processed paper. It offers superior heat-transfer and moisture permeability, and ensures efficient heat exchange (temperature and humidity) when inlet and exhaust air supplies cross inside the unit.

The ability to deliver simultaneous air exhaust and supply is what provides effective ventilation and energy recovery. Conventional ventilators such as extract propeller fans do not work effectively within air-tight buildings because of the negative air pressures involved.

There are further advantages as the heat recovery systems can be linked to a building's air conditioning system, and fully controlled so that they work in harmony.

Poor air quality is believed to contribute to a loss in productivity, low morale and higher rates of sickness among many employees. Providing good ventilation alongside air conditioning is to provide conditions under which people can work, relax and shop in comfort.

Mitsubishi's research has shown that if heat recovery systems were adopted across the market, it could lead to potential savings of nearly 500,000 tonnes of CO2 by 2012.

When increased free cooling and energy recovery are linked to the other initiatives in the Green Gateway Initiative, the industry can start to make a difference to the nation's energy consumption.

www.greengatewayinitiative.co.uk