The efficient connection of refrigeration systems, heat recovery and geothermal energy is a major challenge in terms of control technology. The integration of functionalities for the use of geothermal energy is a logical development of the E*LDS system.
Geothermal energy and heat recovery
Refrigeration systems are always also heat pumps and, hence, potential sources of heat. For this reason, heat recovery for the heating of drinking and heating water has for a long time been customary when fitting out refrigeration systems in food retailing as well as in other sectors where large-scale refrigeration systems are used.
In the past few years, geothermal heat has increasingly been used as a renewable energy source – usually in the form of near-surface geothermal energy generated with the aid of geothermal probes and collectors. Heat pumps raise the heat extracted from the ground to a level where it can be used for heating purposes.
Where refrigeration and heating pump circuits as well as heat transfers to heating and drinking water treatment are optimally coordinated, the energy efficiency of such plants can be increased considerably.
Control technology combines heat flows
Control technology is used to combine heat pump and refrigeration circuits and to harmonise all technical heat transfer processes. Given the appropriate process design and control, the annual heating demand of a food product market, for instance, can be covered exclusively by geothermal energy and the waste heat from the refrigeration system.
Systems of this kind place particularly high demands on refrigeration and building management systems, as a relatively high number of field devices need to be integrated. The compressors of the heat pump system can be controlled by the VS 3010 WP pack controller which was specially designed for this kind of purposes.
Case controllers for electronic expansion valves (UA 400 E) ensure the controlled heat transfer, both from the brine (ground) and at the refrigeration system condenser to the refrigerant in the heat pump circuit. The water-related heat pump control is implemented with the aid of a GLT 3010 which is perfectly adapted to interact with VS 3010 WP and UA 400 E.
Using synergies for the refrigeration system
The refrigerant of the heat pump circuit effectively absorbs the condensation enthalpy at the refrigeration system condenser and can also be used for sub-cooling. Hereby, the thermo-dynamically usable refrigeration capacity and the COP value are increased, and the generation of flash gas, minimised.
During the summer months, geothermal energy can be used for cooling. The ground as heat repository regenerates itself.
- Integration of refrigeration system and geothermal energy increases energy efficiency
- Geothermal energy for heating and cooling
- Using synergies for optimising the refrigeration system