A starting point for reducing energy use
Looking at how hot-water is produced for your building can be a catalyst in significantly reducing its overall energy consumption. Jeff House of Baxi Commercial Division provides the perspective and suggests technological solutions.
Operators of commercial buildings are coming under increasing pressure with regard to energy costs and carbon emissions. On one hand we have a Government policy mix intended to deliver a significant reduction in carbon emissions through a selection of incentive and levy schemes. At the same time the cost of energy is continuing to rise, with no abatement in sight. This combination of factors is prompting estate and energy managers to take stock of their existing building-services provision with a view to increasing efficiency.
Achieving the Government’s legally mandated carbon-reduction targets is based, to a great extent, on how power is generated, involving a switch from fossil fuels to renewable energy sources and a clear move towards local micro-generation. The commitment to reducing overall UK carbon emissions by 80% of 1990 levels by 2050 will be a serious challenge, and the Government appreciates that achieving this target will involve a step change, affecting both the way energy is generated and the way it is used at a local level.
The built environment is responsible for about 40% of the overall UK carbon emission, and Building Regulations are moving towards an ambition of zero-carbon new construction by 2019. However, it is estimated that 75% of today’s buildings will still be in use in 2050, hence the development of policy measures to tackle emissions from existing buildings.
Research indicates that producing hot water can on average account for some 15% of total energy consumed in a non-domestic building; clearly this figure will be significantly higher in certain sectors — hospitality and leisure for example. Therefore water heating is a clear candidate for an energy cost audit, and a reduction in energy use to reduce costs will undoubtedly lessen a building’s carbon footprint.
Although businesses may be able to achieve immediate cost savings by simply making less use of energy-reliant devices or systems, this is unlikely to be a strategic long-term solution. Generally speaking, using energy more efficiently is the best way to achieve sustainable reductions. As far as water heating is concerned, to upgrade or replace current less-efficient solutions will involve capital investment, but this cost can be expected to be recovered over an acceptable period from the ongoing savings on energy bills and, in some cases, Government incentives.
The Government clearly supports investment in more efficient heating systems, as businesses that install water heaters and boilers qualifying for inclusion on the Energy Technology List (ETL) can claim tax relief under the Enhanced Capital Allowance (ECA) scheme. Alternatively the recently launched Renewable Heat Incentive (RHI) allows businesses investing in selected technologies, such as solar thermal, to apply for ongoing payments for metered renewable heat generation for up to 20 years.
|CHP is becoming increasingly popular in locations with a year-round demand for electricity an heat. These are Dachs mini-CHP units from Baxi-SenerTec.|
There are several options when it comes to improving or replacing an existing hot water system. De-centralisation of heating and hot water should be considered if applicable, as separate consideration of respective heat demands can deliver significant efficiency benefits. This solution utilises condensing boiler technology to meet the space-heating load and separate direct-fired condensing water heater technology to meet the hot-water requirement. Case studies have shown end users reporting a reduction in gas use for hot-water production of up to 65%, delivering substantial associated reductions in carbon emissions. When a replacement system is being considered, a prefabricated modular heating solution, constructed off site, can greatly reduce design, manufacturing and installation processes, with production cost savings of as much as 30%.
Microgeneration is a key part of the transformation in energy production and use necessary to attain UK climate change and energy goals. Consequently, a technology of proven effectiveness, CHP (combined heat and power), is becoming increasingly popular in locations with a year-round demand for electricity and heat. As part of a comprehensive campaign by a public sector body involving some 17 locations, mini-CHP units helped lower overall carbon emissions by some 20%, with a similar reduction in energy costs.
Whatever the preferred hot-water solution in a refurbishment project, care should be taken to ensure that it is capable of integration, either immediately or subsequently, with an LZC (low to zero carbon) renewable-energy source. Generally speaking, the low-carbon energy source will be used to pre-heat the cold water inlet into the hot water system, thus reducing the fossil fuel consumed by the primary heating appliance, which needs only to top-up the pre-heated water temperature to the set-point temperature.
Applying LZC requires a detailed appraisal of system and plant operation to deliver the required level of fuel efficiency and carbon mitigation. In this context, it is advisable to seek advice from a heating-industry leader able to contribute at all stages of a project to ensure the selection of energy-efficient systems that enable implementation in stages, with the assurance of component compatibility as full integration is achieved.