Air Conditioning World: How heat pumps are destined to help save the planet

THE debate about our global future continues to heat up as everyone gets incredibly serious about the damaging effects of modern life on the environment.
And no wonder as scary predictions loom large suggesting that if we do not do something about it now, then the increase in greenhouse gases could reach double pre-industrial levels as early as 2035, virtually committing us to a global average temperature rise of over 2°C.

There remain one or two hardcore sceptics who try to deny climate change is a harsh reality but, whether you believe in climate change or not, air conditioning has previously been seen in a bad light by many outside the industry who are concerned about energy consumption and the environment.

Now, one of the country's largest suppliers of heating and cooling equipment - Mitsubishi Electric - is calling for a fundamental review of the way we heat and cool our buildings. It is highlighting the fact that the heat pumps at the heart of modern air conditioning can help reduce energy consumption while providing the modern levels of comfort demanded.

The company also points out that this will not only be good for the environment but it can help reduce the energy bills of individual companies as well.

To stimulate debate and get the ball rolling, the UK Living Environmental Systems Division (LES) of Mitsubishi Electric has produced a 10-point action plan under its 'Green Gateway Initiative'. The company says that, if widely adopted, the plan will contribute to the reduction of more than three million tonnes of CO2 emissions a year by 2016.

The initiative includes technological developments and new thinking combined with simple behavioural changes such as better maintenance regimes or not using the thermostat as an on/off button.

All the moves focus on creating a significant impact on CO2 reduction in the UK's building stock by reducing energy consumption and the energy bills of both consumers and businesses.

Much of the company's plans centre around the utilisation of untapped heat energy that exists in the air all around us and the wider use of cool outside air to keep the need for mechanical cooling to a minimum.

Commercial director Donald Daw, who met with politicians at the House of Commons, to launch the initiative explained more: 'The boom in air conditioning in modern offices looks set to continue as Building Regulations impose limits on the air quality and temperatures that the occupants of building can work in while the amount of heat-generating computer and other equipment increases.

'We estimate that the VRF (variable refrigerant flow) air conditioning sector could account for up to 1.6M tonnes of CO2 emissions a year for cooling and that this figure could increase to 2.4M tonnes of CO2 a year (even with increasing efficiency) by 2016 if current behaviour isn't changed.

'Like all mechanical heating and cooling equipment, air conditioning units consume energy so, as a nation, we need to ask how we can answer the need for a comfortable indoor climate in our offices without adding to the problems for the outdoor climate?'

No going back

With the introduction of stricter Building Regulations, we cannot simply go back to the days before mechanical cooling was invented - even if we wanted to. However, we can and must realise there are now very energy efficient ways of providing a comfortable year-round internal environment that minimises harm to the external environment.

Don't forget that if you reduce the energy a building consumes, you also reduce the overall energy bill and even a reduction of a few per cent a year can make a huge difference to the bottom line.

'One of the easiest ways of achieving a significant reduction in CO2 emissions would be through the greater use of heat pump technology which extracts free energy from the surrounding air,' explained Daw. 'The energy in the air that surrounds us is a key sustainable resource that doesn't currently factor into people's thinking. We need to focus on promoting heat pumps as they are a big solution to the global warming issues we all face today. This technology is already well known in the air conditioning market and is used for heating in countries such as France and Sweden.'

With a conventional gas boiler, 1kW of energy consumed by the boiler delivers less than one kilowatt of heat to a building. With a typical heat pump, one kilowatt of energy delivers a heat output in excess of 3kW - that's a 300% increase in energy efficiency - and that is set to grow as the technology develops.

As the UK's gas reserves decline, the economic and political future of importing gas from around the globe comes into sharp focus and our reliance upon fossil fuels continues to be questioned.

'The optimisation of grid electricity is key to the future of any sustainable energy policy whether the primary source is from fossil fuel, nuclear or renewables such as wind or tide,' asserted Daw. 'If we can make better use of this electricity, then we reduce CO2 emissions and can be less dependent on imported energy.

'By 2016, we estimate that the country could save more than three million tonnes of CO2 per year through the adoption of new air source technologies and improved practices - that's the equivalent of taking more than 830,000 cars off the UK's roads.'

In our homes, more than 80% of energy use goes on space and water heating and the company encourages the installation of new heat pump boilers, which produce more than 30% less CO2 than gas boilers. In particular it is keen to focus on the new build residential sector where all new homes will have to be zero-carbon by 2016.
In the commercial sector, the company's most significant initiative calls for more promotion of the reduction in energy use that businesses can get from replacing older heating and cooling equipment.

'We estimate that businesses will be saving nearly 500,000 tonnes of CO2 a year by 2016 if they are encouraged to quickly phase out old cooling equipment and introduce modern technology,' explained Daw. 'That's not only good for the environment, but it will also make a big impact on the energy bills of individual companies.'

More effective

A year-long trial at Mitsubishi Electric's Hatfield headquarters has also shown modern, inverter-driven air conditioning is much more effective and energy efficient at providing heating and cooling than the traditional boiler in the basement and chiller on the roof. The trial compared a boiler/chiller combination with a City Multi WY water-cooled condensing unit linked to a ground source slinky to extract geothermal energy from the earth.

What also became apparent is that a normal air sourced air conditioning system is also more efficient than a boiler / chiller system. Air sourced heat pump systems are much more attainable for the vast majority of commercial properties than a ground source system and the research shows that the air sourced system produces over 1,900kg less CO2 emissions per year when compared with boiler and chiller.

'The current 'yoyo' practices of using gas boilers for heating and air conditioning for cooling, is no longer sustainable and when it comes to cooling, 'free cooling and heat recovery' strategies are of significant importance,' he added.

The use of fresh air and natural ventilation when combined with an air conditioning system reduces commercial energy consumption significantly. In terms of heating, reuse of the warm air being expelled from a building to provide energy back into the building is far better than warming-up the outside.

Mitsubishi Electric LES has set targets to reduce CO2 emissions through actively using its market footprint to challenge engrained thinking and to develop new approaches to support customers in achieving their CO2 reduction goals by helping them make the right purchasing decisions.

The company has already been quick to back its words with action and has stunned the air conditioning industry by questioning whether a rapid growth in residential air conditioning in the UK is either necessary or sustainable.

'If the government is to be supported in meeting its targets for CO2 reduction then we have radically to change the ways in which we heat and cool our homes, schools, factories, shops and offices,' explained Daw. 'As a nation, we have to accelerate change in heating and address cooling in a responsible manner. Managing the internal temperatures of the environments in which we live, work and learn has to keep pace with the new technologies that are available and the incremental savings in CO2 that are eminently achievable.'

Mitsubishi Electric LES' Green Gateway Initiative is primed for the low carbon generation - asserting that every company's responsibility is to its stakeholders. Stakeholders include the individuals that purchase goods and services from companies and the fellow citizens that are both directly and indirectly affected by those purchasing choices.

A copy of the Green Gateway Initiative report can be downloaded by visiting or aircon.
1 September 2007


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