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High capacity heat pumps for providing heat for industrial plants and buildings are still a rarity in Germany - and the trend is rising. This is because they can play a decisive role in the decarbonisation of the heating sector and in achieving climate targets. A Fraunhofer study commissioned by Agora Energiewende even states: "The entire German demand for heat up to 200 degrees Celsius can technically be met entirely by heat pumps. High capacity heat pumps with an output of 500 kW or more play a particularly important role in this." This could save three quarters of Germany's natural gas consumption - and, in purely mathematical terms, cover the entire demand for building heating and hot water as well as a good third of industrial process heat.

However, only 100 MW are currently installed in Germany, with a further 600 MW under construction or in planning[1]. In order to become climate-neutral by 2045, an annual thermal capacity of four GW would have to be added.

[1]https://www.heise.de/hintergrund/Studie-Grosswaermepumpen-koennen-drei-Viertel-des-deutschen-Gasverbrauchs-sparen-9187670.html

To operate a high-capacity heat pump, an abundant heat source is required. The heat can come from air, earth, river or lake water, industrial waste heat or waste water. In contrast to a network with decentralised, normal heat pumps, for example in a neighbourhood of detached houses, the corresponding distribution network runs at a higher temperature level. This is because very large heat pumps (HPs) in the MW range are always located at the source: as a result, the network itself has a higher temperature, which may already be able to cover a large part of the heat demand. A booster HP can then be placed there for certain processes, which reduces heat losses in the distribution network and thus increases the overall efficiency of the network. In contrast, networks with small, decentralised heat pumps, which are located in every house, generally have the temperature level of the heat source - i.e. it is cold. 

High-capacity heat pumps are particularly useful where there is a need for both heating and cooling, because like its little brother, the large heat pump can do both. They are ideally suited for combination with district heating networks, horticulture and agriculture, swimming pools, office buildings, hotels, hospitals, supermarkets and catering.

These applications usually have a high demand for heating and cooling and can benefit in particular from lower energy costs for heating and cooling. A business case can be made if there is a year-round demand for low-temperature heating and cooling, which is controlled fully automatically and monitored by smart meters. Then the investment costs in a large heat pump solution will soon have been amortised.

A high-capacity heat pump works in exactly the same way as its smaller brother: heat is extracted from a renewable source and transferred to a refrigerant, which transfers the heat to a carrier medium at a higher temperature level via a heat exchanger. This can be water, for example, which is used to provide heat. The temperature transfer causes the refrigerant to liquefy again and is expanded before the process starts again. For cooling, the cycle is simply reversed and heat is extracted from the building, transferred to the refrigerant and then returned to the original heat source using the heat exchanger. 
In this cycle, additional energy in the form of electricity (ideally from renewable sources such as photovoltaics) is largely only required for compression and expansion; the remaining energy is obtained from the respective heat sources (e.g. ground or aquathermal). There are also more and more direct evaporator systems, especially for high-capacity heat pumps, which are complicated to control but can save a lot of additional electricity and thus increase efficiency.
We have described in this blog post how the efficiency of a heat pump is represented by the seasonal performance factor and coefficient of performance (COP). However, the COP tends to be higher if the temperature difference between the source and consumer is lower.
High-capacity heat pumps often consist of several cascaded heat pumps in order to minimise the necessary heat loss.

As the heat pump output is more expensive than a gas boiler, for example, it is generally worth installing larger heat buffer storage tanks. The stored heat allows load peaks and fluctuations in source availability to be (partially) absorbed cost-effectively. The same also applies to self-generated electricity, for example from PV or wind. The aim here is always to consume the self-generated electricity as much as possible in order to operate as cost-effectively as possible and not to have to purchase the electricity at high cost and feed it into the grid at minimum prices. 
In addition to the advantages of a more efficient energy concept (the combination of heating and cooling by means of heat recovery as a heat pump source in combination with self-generated renewable electricity and storage reduces the dependency on external producers as well as the overall energy requirement and thus saves operating costs.

High-capacity heat pumps are also increasingly being used in projects to create and transform district heating networks. 
goodmen energy has already been able to advise a number of local authorities on this and has, for example, planned the decarbonisation of a network that is fed from wastewater and river water and activated by a high-capacity heat pump. Waste heat from process exhaust air and process water can also be recovered on a large scale in industry using high-capacity heat pumps. The high temperatures ensure that the heat pumps are highly efficient. Due to the resulting reduction in heat demand (to a COP 3-4), funding opportunities and, in some cases, possible operating subsidies and the rising price of CO2, the investments are already amortising within a reasonable time frame in many cases.

Indoor swimming pools generate large amounts of waste heat, which is often released unused into the environment. With an exhaust air high-capacity heat pump, it is possible to recover this waste heat in a targeted manner, recycle it and thus reduce the overall heat requirement. A fan integrated into the exhaust air heat pump draws in the heated air from the indoor pool, uses it as a heat source for the heat pump unit and discharges the cooled air to the outside. By utilising this waste heat, both primary energy consumption and CO2 emissions can be reduced. 
In our feasibility studies for Stuttgart's swimming pools (indoor, outdoor, thermal and river pools), we have also designed with corresponding high-capacity heat pumps and the utilisation of waste heat, hot water, thermal springs and river water.

The launch of another remarkable project took place in Prague at the beginning of December 2023: As a partner of the Czech project developer JN infra AS, goodmen energy is planning floating energy centres, known as ComPons, as well as the associated heating networks on land. The pontoons are equipped inside with high-capacity heat pumps fed by river water, which are attached to the shore. They are designed to supply heat energy to urban neighbourhoods near navigable rivers (read press release in German here).