Switching to a greener future
In the commercial sector, the use of low carbon zero (LZC) technologies is gaining some traction but these are predominantly specified for new build premises, when in fact retrofit applications can offer just as significant returns on investment. Here, Sean Green, Senior Product Manager at Baxi Commercial takes a closer look at heat pumps – a versatile solution for the delivery of efficient heat and hot water both in new and existing commercial buildings.
The non-domestic sector contributes to 38% of the UK’s carbon emissions, and as such has an important part to play in meeting the country’s carbon reduction commitments. To achieve meaningful carbon savings, we need to maximise efficiencies where energy use is highest – this means at least considering the use of new heating and hot water technologies in commercial or public sector buildings.
As it stands, more renewable and low carbon technologies are installed in new build properties than existing ones. Although this uptake, being largely driven by legislation, is encouraging, new buildings account for a small number of the commercial buildings located in the UK. In fact, just one in five commercial buildings are new builds. This means there are vast opportunities for upgrading existing heating and hot water systems which have not yet been explored.
For some businesses and organisations, the prospect of investment in a renewable or low carbon technology can seem on the face of it to be too expensive, but there is a solid business case for LZC equipment. If the right products are correctly specified for an application, the energy savings can be substantial, thus delivering tangible operational cost savings as well as a higher level of carbon compliance that could be essential to meeting future legislation. Some renewable and low carbon products are also included on the Energy Technology List, so are eligible for an Enhanced Capital Allowance to bring down the cost of installation.
When renewables began making an impact on the UK commercial heating market around 10 years ago, solar thermal water heating was an early leader in the field. After all, the technology had been around for many years and people were relatively comfortable with it. However, as the renewables and low carbon market has grown and diversified, other technology is coming to the fore. One particularly versatile option is the heat pump.
Heat pumps essentially draw ambient heat from either the air or ground and convert it to useable heat through a thermodynamic process which is similar to the way a refrigerator works, but in reverse. Heat pumps come in many outputs and can be suitable for large, commercial use as well as domestic applications.
Gas absorption heat pumps (GAHPs)
Gas absorption heat pumps are a good low carbon solution for cutting running costs and carbon emissions, as they provide around 65% free energy. The evaporation cycle is driven by a gas burner to start and sustain a refrigeration cycle, supplemented by energy from ambient air to increase the thermal output. The heat produced can be used to supply low temperature hot water for space heating and/or for the production of domestic hot water via an indirect cylinder, similar to a traditional boiler.
GAHPs, such as our A-Cubed heat pump, can deliver efficiencies of up to 141% which is 60% more than standard condensing boilers – and could achieve an A+++ rating under the expected requirements of the ErP Directive.
As with standard condensing boilers, it is possible to cascade GAHP units up to 100kW, and the heat pumps can also be installed to run alongside traditional boilers. This allows for a commercial building’s heat load to be better distributed to increase the longevity of the equipment and reduce disruption to users when the heat pumps or boilers require maintenance or repair.
Air source heat pumps are considered easier to install than a biomass boiler or ground source heat pumps and can be easily integrated with underfloor heating systems, particularly in new builds. Compared to a boiler, heat pumps require less maintenance and servicing over the lifetime of the system for a largely ‘fit and forget’ installation.
Most GAHP units can be installed inside or outside, to free up space in the plant room. There are many compatible controls available which can be used with the heat pumps to maximise comfort, so building users retain all the flexibility of a traditional heating system, but with less carbon emissions.
While GAHPs can provide both heat and hot water provision for a commercial application, there are alternative air source heat pumps which focus solely on pre-heating mains cold water to support gas fired water heaters. These heat pumps – such as our AMBIflo – are a practical alternative for sites where it is not possible to use solar panels and can also be installed outside.
Ground source heat pumps (GSHP)
Ground source heat pumps are highly efficient units which harness the earth’s geothermal energy to provide efficient heat and hot water. At a depth of around 1 to 2 metres the temperature within the ground remains fairly constant at around 10ºC to 12ºC, as it is continually heated with solar rays.
Ground source heat pumps harness this energy through either ground loops, installed laterally across a larger area of ground, or a bore hole if space is limited, which extract the ambient heat to commence and sustain refrigeration within the heat pump.
GSHPs offer a coefficient of performance of between 3 and 4, which means that for every unit of electricity you put in, you get between 3 and 4 units of heat out. Baxi Commercial’s GEOflo has a best-in-class coefficient of performance of 4.7 when used with a low temperature heat load such as underfloor heating.
Like the gas absorption heat pumps, GSHPs can be cascaded for a multi-unit installation and used together with commercial boilers to boost the efficiency of a building’s existing heating and hot water provision.
Some heat pumps are eligible for the Government’s Renewable Heat Incentive (RHI) scheme, providing an additional revenue stream to reduce payback times and enhance return on investment.
Open to commercial organisations since November 2011, the RHI scheme is designed to bridge the gap between the cost of fossil fuel heat installations and renewable heat alternatives through financial support for owners. The RHI essentially pays participants of the scheme that generate and use renewable energy to heat their buildings, and can provide regular income for commercial organisations who choose to go green.
As the commercial heating market evolves, more renewable and low carbon technologies will become available – all delivering heat and hot water solutions to meet the demands of users, but with ever increasing efficiencies. For advanced technologies, like the latest generation of heat pumps, to really make an impact on the UK’s carbon emissions, they must be embraced by the commercial sector and more widely incorporated into retrofit applications to bring down energy use for the benefit of both the bottom line and the environment.