Using operating power which is generally electrical, heat pumps lift thermal energy from a low temperature level, which cannot be used, to a higher level which can be used. An example of this is in the Zurich Abattoir, where high-temperature heat pumps from thermea. Energiesysteme GmbH ensure that energy from waste heat can be recovered for heating and hot water.
High-temperature heat pumps with transcritical GEA CO2 compressors used in the abattoir Zurich
The abattoir, which is more than 100 years old, is one of the most important meat-processing plants in Switzerland and employs almost 500 people. The owner of the site and building is the City of Zurich. The plant serves as a model for a lot of abattoirs in Switzerland and abroad.
The high-temperature heat pumps in the Swiss abattoir operate with the environmentally-friendly refrigerant R744 (CO2), and they consist of a total of 12 virtually maintenance-free transcritical GEA CO2 compressors. The heat output of the HGX34/150-4 SH CO2 T models is a total of 800 kW.
Heating water with a flow temperature of 90°C and a coefficient of performance (COP) of over 3.4 is generated. More than three times of the energy input used is available by this means as usable heat output.
This high degree of efficiency is achieved by a comprehensive hydraulic optimization of the supply system, so that low return temperatures from the systems for domestic hot water supply and building heating are possible throughout the year.
The heat sources are connected to each other by a closed cooling water circuit, and they are transported to a waste-heat buffer reservoir, which is cooled by the heat pump.
Thanks to the concept of heat recovery with R744 as a refrigerant, not only energy costs, but also CO2 emissions to the environment, are reduced significantly: The annual output of carbon dioxide can be reduced by more than 510 tonnes, while 260,000 m³ of natural gas are saved.
On the right side, you can find a picture of the installation of the heat pumps in the abattoir Zurich.
Transcritical GEA HG34 CO2 T Compressor
The gas-cooled semi-hermetic piston compressor HG34 CO2 T is ideally suited for use in transcritical CO2 applications. The compressor uses the natural refrigerant R744 (CO2) which presents a very low Global Warming Potential (GWP) of value 1, and can therefore be seen as a climate neutral refrigerant.