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How green is your heat pump?

Investment in green technology is booming, and sustainable products are in demand. However, it’s challenging to understand which products are best for the environment when everything is promoted as green. This is clear in the heating industry, where pretty much any solutions that are better than a fossil fuel burner is promoted as green. Heat pumps vary significantly in terms of environmental impact, so we need to put the ambition higher.

More people are trying their best to reduce their carbon footprint as they are starting to realize that there is no planet B. Despite many ongoing initiatives to reduce our carbon footprint, we have had an all-time-high in greenhouse gas emissions 2019. Moreover, environmentally friendly consumption is especially difficult, when nearly every product of the same category is being promoted as environmentally friendly, simply because they are better than very old-fashioned fossil-based technology.

Heat pumps are superior to the fossil fuel burner

Ideally, heat pumps are supplied with electric energy from renewable sources. But even if the electricity is produced by fossil-fueled power stations, heat pumps are far more efficient than the most efficient condensing type boiler. This means far less primary energy consumption and less CO2 in the atmosphere. In other words, electrically driven heat pumps consume less energy than burner solutions, resulting in a larger contribution to reducing the environmental impact of a heating solution.

Not all heat pumps are equally environmental friendly

So, heat pumps are a more sustainable solution than a fossil fuel burner, but just how sustainable the heat pump is, varies with the technology involved. A comparison can be made with the car industry. Electric cars are being marketed as the solution to decarbonizing the transport sector and are by all means great since electric cars - even with poor energy mix - are better for the environment than combustion engines. However, without being an expert in electric cars, car batteries vary a great deal in terms of environmental impact, such as carbon footprint in production and the mix of metals in the cathode, not to mention the transparency of the supply chain and batteries' wasting and recycling processes. So it is important to not just to settle with a solution that is better than a combustion engine. And it is the same for HVAC-industry – we shouldn’t settle for a solution simply because it is better than a fossil fuel burner.

Total Equivalent Warming Impact (TEWI) is a good measurement

The use of different technologies in heat pumps gives them different impact on the environment. To measure the differences between heat pumps, an index called TEWI (Total Equivalent Warming Impact)  should be used.

TEWI takes into account Seasonal Efficiency Simulation for the specific application and specific climate regions. Different heat pumps have different energy consumption if they are located in, for instance, Italy or Norway. The outcome of efficiency rating with Seasonal Efficiency Simulation is much more precise and relevant compared to the nominal efficiency that drives many incentives schemes and governmental programs.

The type of refrigerant with different Global Warming Potential is also included in the TEWI index. GWP gives the Carbon footprint of the substance in terms of how many Kilograms of CO2 are equivalent to the Warming impact of 1Kg of refrigerant. The most common refrigerant used in Heat pumps has a carbon footprint 2000 times higher than the CO2. But there are new technologies with lower impact refrigerants coming into the marketplace. Moreover, the charge of refrigerant is also included in the TEWI measurement simply because the environmental impact of the units increases with the amount of refrigerant that is used.

In short, TEWI measures the actual warming potential generated by the CO2 footprint – the lower the TEWI value is the lower the carbon footprint of the heat pump will be.

A smart system is imperative for a low TEWI

Modern non-residential buildings often require simultaneous heating and cooling in different parts of the building. A multifunctional heat pump can move energy between areas within the building, further increasing the overall efficiency of the system and lowering the TEWI. But we shouldn't only evaluate the singular heat pump, it is important to look at the entire system when evaluating the carbon footprint. Therefore, having an intelligent control system solution, which integrates heat pumps with air handling units, pumps and terminal units, is imperative for a low TEWI value.

Swegon will soon launch a new heat pump that will set a new benchmark in terms of the lowest TEWI for commercial HVAC application as of 2021. The technology of these products together with advanced control functions will make it possible to maximize the efficiency of the whole system. It’s not just the car industry that is moving fast towards more sustainable solutions, the same applies to the HVAC-R industry – so keep an eye on the new products and systems being developed, and let’s work together in ensuring the best environmental quality, indoors and outdoors.