Plant & Works Engineering April 2022

42 | Plant & Works Engineering www.pwemag.co.uk April 2022 Energy & Environmental Management Focus on: HVAC Are heat pumps the answer to the energy crisis? Given that Europe is currently in the midst of an energy price crisis, many businesses are looking to alternative, renewable means of decarbonised heat. Luke Worrall* explores why heat pumps may offer a reprieve for industry. W ith gas prices at record highs, any business operating with gas boilers will already be acutely aware of the impact of fluctuating prices and the inherent risks of relying entirely on energy derived from fossil fuels. Many then, are looking to alternative, renewable forms of energy. While for most businesses a complete transition to net zero will not be possible overnight, heat pumps may well deliver a perfect trifecta of reduced carbon footprint, improved energy efficiency and reduced energy costs. Pumping heat So, what exactly is a heat pump? Although there are several types: They all work on the same basic principle: they take low grade energy generated by the sun and use refrigerant technology to increase this heat to a usable level. Air source heat pumps (ASHPs) use energy in the air, or from the exhaust systems of buildings as their heat source. Ground source heat pumps (GSHPs) use energy from the ground, using a transfer fluid to absorb the heat at low temperatures, passing this through a heat exchanger and into a heat pump. Finally, water source heat pumps (WSHPs) extract heat from water so that it can be reused for space heating and hot water. WSHPs can be connected to rivers, lakes, boreholes and even effluent discharges from industrial processes. With a correctly designed system, heat pumps can deliver carbon savings of over 70% when compared with traditional oil and gas heating. Annual running costs are also lower and, because heat pumps are highly efficient, they can generate between 3.5kW to 4.5kW of energy for every kW of electricity they take to run. Benefits of heat pumps It’s important to think outside the box when considering heat pumps. There’s often a misconception that, because the flow temperatures you can achieve using heat pumps are normally relatively low, around 45- 55oC, that they aren’t appropriate for use in a commercial facility. However, it is possible to install high temperature heat pumps that can deliver temperatures of 80oC. What many people don’t often consider is that higher temperatures aren’t always necessary. For space heating, for example, facilities can use heat pumps for the majority of the year. It’s only on the coldest days that you might need to top up with energy derived from fossil fuels. But even that might not be necessary if you can recover energy from waste heat from a building or process. Waste heat can be recovered from a ventilation fan from an industrial process, or from effluent, for example, and can be put through a heat pump, being recycled back into usable heat. For manufacturers with process heating requirements, heat pumps can be used for pre- heating raw materials or to top-up water for washing down equipment at the end of a shift. It’s clear that heat pumps, which can be powered by electricity from renewable sources, have a lot to offer. The key is to rethink the traditional ways of providing space and process heating. *Luke Worrall is business development manager at heat pump