Decarbonisation Technology - November 2022

The heat-pump way to more sustainability

The heat pump as an industrial technology has been mature for decades, but only now with sustainability demands and price of fossil fuels is it coming of age

Rasmus Rubycz Atlas Copco Gas and Process

T he industrialisation of much of the world over the past few centuries has been predicated on an abundance of fossil fuels as energy sources. And until the last 40 or 50 years, whether coal, oil, or natural gas, this was hardly seriously questioned. It is easy to figure out why: cheap energy powered the modern world and helped develop modern consumer societies, first in Europe and the US, then further afield. There was, however, a major price to pay: burning fossil fuels to power modern industry is the main cause of climate change, experienced in extreme weather, poor air quality, and species extinction across the planet. Nevertheless, if albeit belatedly, attitudes to fossil fuel use are changing, and not just because climate demonstrations have put greater pressure on governments, businesses, and industries. For the first time in modern history, the goals of many politicians, business leaders, and climate activists are aligning: the consensus is that green sources of energy must replace fossil fuels if we are to continue to power modern societies. At the same time, the reasons and motivations underpinning this growing consensus vary, with some people more concerned about protecting the planet, for example, and others more focused on the continued existence of a specific business or business model. But whatever the reason, they all agree that the result must be a rapid transition to a more sustainable way of living. End dependence on fossil fuels While notions of sustainability have long underscored the reasons for providing green

energy sources, more recently it has also become about efforts to minimise the effect of geopolitical crises, volatile prices, and disruptions to fuel imports. Green hydrogen, for example, is one much-touted alternative energy source, something frequently depicted as a transformative solution to help end dependence on fossil fuels. Often overlooked, however, is that it is produced from electricity with high energy losses, and it still requires greater efficiencies before its wide-scale deployment. Similarly overlooked is that in many situations heat pumps can do the job as well as hydrogen does, and even increases in electrolyser efficiency will not change this fact. That is not to downplay the potential of hydrogen, and there are many industrial applications for which it can be used sensibly, such as with high temperatures for combustion, direct chemical reaction, or long-term energy storage. Indeed, the decentralised production of hydrogen on-site in chemical and petrochemical production plants offers upcoming opportunities to not only use the produced green hydrogen, but also to use the unavoidable waste heat. Temperature disparity While there are industries and processes that require high temperatures, there is also a lot of demand for energy below such high levels. Unfortunately, we usually use extremely hot flames to generate even low temperatures, even though it is not necessary. Temperatures of only 100-250°C are required in paper production, district heating, the food industry, and parts of the chemical industry, for example (see Figure 1 ).