Heat recovery on CO_2 refrigeration systems for supermarkets
The project seeks to analyze and demonstrated the opportunities there is for heat recycling on a cooling system for supermarkets’.
The main objective of this project is to analyse and demonstrate the possibility for heat recovery on supermarket refrigeration systems. The heat is used to reduce the consumption of heat and electric energy in other energy demanding processes in the supermarket. The project will also support the popularisation of natural refrigerants by using CO_2 refrigeration systems, which have special advantages in combination with heat recovery. The first phase of the project will concentrate on finding the most efficient technology for utilising heat from the cooling system. Different heat driven processes will be analysed by means of combined system modelling. The different technologies will be evaluated with regard to the energy and cost savings potential. The most cost-effective solution will be chosen for demonstration. In the second phase, a demonstration system will be built in a selected supermarket. The third phase will comprise data collection from the operation of the demonstration system. The fourth phase will comprise analyses and conclusions obtained from the test results. At the same time, project results will be disseminated. The project is in its start-up phase. The project results will be used to extend and improve the product range of the project participants. The heat recovery system developed in the project will give the supermarkets the opportunity to choose energy efficient refrigeration systems based on natural refrigerants that to a high degree are in demand after the Danish HFC refrigerant legislation was introduced in 2007.
From being a new but promising technology in relation to the transition to refrigeration plants using natural refrigerants in the supermarket industry at the beginning of the project, trans-critical CO2 has matured during the project as a cooling technology in supermarkets. Thus, there is currently a full component range for CO2 including dedicated controllers. Currently, trans-critical CO2 covers the entire market of new installations in Denmark, and it also has good footing abroad (mainly Britain and the Nordic countries).
Various users of the recovered heat has been studied (hot water and heat driven cooling processes: Ejector, ab-and adsorption and sorption), which has led to the focus of the project, i.e. heat recovery for domestic hot water and space heating.
At the beginning of the project, the development of the methods for heat recovery in these plants was not emphasized. However, this project in particular has supported the development and demonstration, so that today it is almost more the rule than the exception that equipment for heat recovery is mounted in new installations. Heat recovery in refrigeration plants is often the only heating source in many plants designed especially for Norway. It has not been found profitable to retrofit heat recovery in existing plants.
Supermarket systems are characterized by having a highly variable load, which means that both the power available for heat recovery and the temperatures by which it can be done vary greatly within a short period of time. Measurements show that in principle it is possible to recover a significant amount of heat at 55°C at an ambient temperature of only 5°C. Here, the plant is, however, running in so-called sub-critical (condensing) operation, where the inlet temperature of the water being heated has great significance on the amount of heat, which it is possible to recycle.
With the introduction of heat recovery, the boundaries between two and sometimes three contracts have become much less clear-cut, namely
- Cooling contract
- Pluming contract
- Ventilation contract
This goes not only for the installation side, but especially for the management and thus the design of complete system.
A need for further training has been identified, in particular concerning pluming, but also within the ventilation industry, I order to create knowledge about interaction and solution when the refrigeration plant and the heating systems are integrated into one unit.
During the project, Advansor, project partner, has been developed into the world´s largest supplier of commercial CO2 refrigeration plants, and from having delivered more than 80 plants with heat recovery in 2010 (which all together constitute almost 10 % of the total number of plants provided by Advansor), today, heat recovery has practically become the rule than the exception.
All the refrigeration plants currently being delivered to COOP, project partner, including heat recovery. Thus, today, approx. 15 % of coop´s total heat consumption is covered by heat recovery.
Key figures
Category
Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| ADVANSOR A/S | 0,28 mio. DKK | 0,45 mio. DKK |
| COOP DANMARK A/S | 0,01 mio. DKK | 0,18 mio. DKK |
| SUPER KØL A/S | 0,01 mio. DKK | 0,10 mio. DKK |
| Teknologisk Institut | 0,58 mio. DKK | 0,37 mio. DKK |
Contact
Teknologisk Institut. Center for Køle- og Varmepumpeteknik
Gregersensvej
DK-2630 Tåstrup, Danmark
www.teknologisk.dk
Reinholdt, Lars , 72201270, lre@teknologisk.dk
Øvr. Partnere: Advansor A/S; Superkøl A/S; COOP Danmark A/S
