GUIDE 2014 case study: Advantageous supermarket refrigeration heat recovery using GEA Bock CO2 Compressors

GEA Bock CO₂ compressors are used in two different applications, a supermarket and an abattoir, in Switzerland to provide many benefits in the fields of refrigeration and heat recovery, as presented in the ‘GUIDE Europe 2014: Natural Refrigerants – Continued Growth & Innovation in Europe’, published by shecco in January 2014.

COOP supermarket in Birsfelden, Switzerland

The Coop supermarket in Birsfelden, Switzerland, employs GEA Bock CO₂ compressors to cool the entire supermarket, ensuring the precise temperature is maintained in cold storage rooms, cooling cabinets, freezer cabinets, and freezer rooms.

The high-pressure stage utilises a frequency-controlled HGX34/150-4 S CO₂ T as well as three HGX34/150-4 ML CO₂ T compressors. A total of three HGX12P/40-4 CO₂ compressors, one of which is frequency controlled, are used for the subcritical low temperature cooling. The refrigerating capacity of the system in normal cooling is approximately 111 kW and at low temperatures is about 20 kW.

Using heat recovery, the energy received from the refrigeration cabinets and rooms can be efficiently used as heat or supply hot water to the supermarket.

Kälte AG Basel installed the CO₂ supermarket system, which serves as a booster system, in 2012. The system uses natural and climate neutral refrigerant CO₂. Italian company Enex srl built the system rack.

Hot water for 100-year-old Abattoir in Zurich provided by 12 GEA Bock CO₂ compressors

The abattoir, more than 100 years old, is one of the most important meat-processing plants in Switzerland and is owned by the City of Zurich. The high temperature heat pumps with GEA Bock CO₂ compressors ensure the energy from waste head can be recovered and used for heating and hot water. The heat pumps lift thermal energy from a low temperature level (which cannot be used) to a higher level, making it useable.

thermea. Energiesysteme GmbH installed the heat pumps, consisting of a total of 12 GEA Bock CO₂ compressors, in the abattoir. The heat output of the HGX34/150-4 SH CO₂ T models comes to a total of 800 kW.

The abattoir heating water is generated with a flow temperature of 90°C and coefficient of performance (COP) of over 3.4, leaving over three times the energy input used available as usable heat output. This high degree of efficiency is achieved by a highly efficient compressor in conjunction with comprehensive hydraulic optimisation of the supply systems, so that low return temperatures from the systems for domestic hot water supply and building heating are possible throughout the year.

Employing heat recovery with R744 as a refrigerant, energy costs and CO₂ emissions are reduced in the abattoir of Zurich. The annual output of CO₂ is reduced by more than 510 tonnes, and 260,000 m³ of natural gases are saved.