Donald Daw, commercial director of Mitsubishi Electric Living Environmental Systems, looks at a joint venture that culminated in the development of a heat pump air curtain
If we are to achieve government emissions targets, we must find more energy-efficient ways of
providing modern comfort levels in our buildings.
It is not possible to go back to the days before mechanical cooling and heating was invented, but modern methods can be used to provide a comfortable internal environment all year round. This can be done in a way that is much more energy efficient than traditional systems.
The air-conditioning industry can take a lead here. This is by demonstrating the environmental value of the heat pump in helping fundamentally to alter the way we heat and cool our buildings.
The added advantage in promoting heat pump systems is that they also have the potential to save the customer money by reducing fuel bills. Heat pumps really can offer a win-win situation for the industry, the customer and the environment.
Political ramifications
This is vital. Throughout Europe more than 40% of our energy is spent on heating, lighting, cooling and running our homes and offices.
In the UK, 50% of CO2 emissions are directly attributable to the built environment, and more than 27% currently comes from energy use in buildings.
That is not only bad for the environment, it also has potential political ramifications because forecasts show that by 2030 Europe will import 70% of its energy. This places us at the mercy of both the world markets and political instability.
So there is immediate need to minimise energy use for environmental and political reasons. But, as previously stated, there are also tangible financial benefits in examining energy consumption and heating and cooling requirements.
Energy prices are rising year on year. Any initiative that can reduce this outlay can lead to significant annual savings.
This is where heat pumps can come to the rescue. Heat pump technology has been around for decades and is already used for both heating and cooling across the globe. Modern heat pumps have moved forward in recent years - for heating they can outperform an equivalent gas boiler by at least three to one.
The system uses the thermo-dynamic properties of refrigerants to absorb heat from one place and release it to another. It uses the ability of the refrigerant to boil from a liquid to a vapour, and its capacity to condense back into a liquid.
Traditional method
Mitsubishi Electric conducted tests at its Hatfield offices during a 12-month period. The tests demonstrated that the VRF ground source heat pump air conditioning system is much more effective at heating and cooling a building than the traditional method. This method uses a boiler in the basement to heat - and a chiller system on the roof to cool - and these results were achieved at last year's gas price.
The heat pump system is able to transfer energy around the air conditioning's refrigerant circuit to transfer heating or cooling. This offsets the energy required for one against the other, thereby reducing the overall energy consumed.
Now, in a development that offers the industry potential expansion into new markets, heat pumps are being used in different ways in new sectors.
Air curtain company Thermoscreens recently teamed up with Mitsubishi Electric to develop a heat pump air curtain. It offers a 67% reduction in running costs and emissions over a conventional direct-electric equivalent.
Air curtains have long been used to ensure that the busy entrances of commercial buildings do not suffer dramatic energy loss every time the door is opened.
Air curtains are also important in the retail sector, where they allow businesses to operate an open-door policy to encourage trade - without allowing all of the heating or cooling energy to escape. The jet of air from the curtain acts as a barrier to help the building keep energy consumption down.
Excess heat
Heat pump water heating is becoming a reality and these systems offer a serious and viable alternative to gas boilers. This is in both the commercial and residential sectors.
For commercial buildings, one of the new specialised heat pump units can divert excess heat energy from a VRF air conditioning system to supply a building's hot water supply - outputting water up to 70º C.
This offers the potential for companies to receive all of their hot water for free. In the residential sector, heat pump water and space-heating systems - such as Ecodan from Mitsubishi Electric - are now available to suit almost any property from the 1970s onwards.
The residential models extract latent energy from the ambient air and upgrade this to useful heat. This delivers improvements in performance over traditional methods such as gas, oil, LPG or direct electric.
Air source heat pump systems, such as Ecodan, are designed to be as plug-and-play as possible, and leave the homeowner noticing little difference from their previous water heating system. They just get reliable hot water when they want.
By 2016, the UK could save more than three million tonnes of CO2 per year through the adoption of new heat pump technologies.
This would be coupled with improved practices and maintenance regimes - that is the equivalent of taking more than 830,000 cars off the UK's roads.
Controllable comfort
When we look at our built environment, modern life demands controllable comfort. What we must all realise and focus on is that, with modern heat pumps, the technology currently exists to help achieve his in a much more sustainable way.
The issues discussed here are part of the Green Gateway Initiative - a ten-point action plan for energy reduction in the built environment. Further details are at www.greengatewayinitiative.co.uk