HEAT PUMPS
HEAT PUMPS: LOWERING CARBON AND COSTS
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he UK has reduced greenhouse gas emissions by 43% compared to 1990, thanks to the rigorous and impactful Climate Change Act. Currently celebrating its tenth birthday, the Climate Change Act was launched in a bid to set a binding emissions target for the UK by 2050. Ensuring that the UK continues to build on the strong foundations set in previous years and remains on track to meeting the third carbon budget will require a concerted effort across all industries. However, certain sectors will require significant attention.
BUILDING EMISSIONS AND THE DECARBONISATION OF HEAT Energy use in the built environment is one of the most important aspects that must be addressed in the UK and
Figure 1: Heat pumps work by absorbing heat from a cold space and releasing it to a warmer one
abroad in the near future. Around 40% of the primary energy use within Europe is related to the building sector, with buildings accounting for 34% of carbon emissions in the UK. Among the key drivers of investment in efficiency include carbon reduction, fuel poverty alleviation and cost savings. The major challenge lies in the decarbonisation of heat. The UK has a particularly rigorous framework for achieving decarbonisation, and the decarbonisation of heat will become increasingly important in the coming years. Nevertheless, doing so will be an arduous task. Decarbonisation policies up to now have mainly affected electricity, leading to fundamental changes and challenges for the sector. It is now time for heat to follow suit. One of the most promising technologies aimed at increasing efficiency and reducing emissions in the building sector is provided by electric heat pumps. Heat pumps offer a modern, low-carbon solution to provide space heating and domestic hot water and are particularly appropriate in countries that have both high heating requirements (in winter) and cooling requirements (in summer). At the time of writing, there
Figure 2: Air-source heat pumps have small physical footprints, though they need to be positioned somewhere with adequate airflow.
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ENERGY MANAGER MAGAZINE • MAY 2021
are 11,279,386 installed in Europe, saving 29.8 million tCO2, producing 116 TWh of renewable energy and providing 60,000 jobs.
WHAT IS A HEAT PUMP AND HOW DOES IT WORK? A heat pump is an electrical device that extracts heat from one place and transfers it to another. Heat pumps are a highly efficient way to heat buildings. They draw in heat from the environment and use electricity to raise the temperature to a suitable level for space heating and hot water. Typically for each kWh of electricity consumed, 2.5-4kWh heat is supplied. Heat pumps deliver lower temperatures than boilers, so they work well with underfloor heating in new buildings or radiators with a larger surface area. The most conventionally applied heat pump is the mechanical heat pump, which is based on the compression and expansion of a working fluid, or ‘refrigerant’. Heat pumps transfer heat by circulating the refrigerant through a cycle of evaporation and condensation. A heat pump comprises four main components: evaporator, compressor, condenser and expansion device. The
