Finnish supermarket puts waste heat from refrigeration to use
A supermarket in the Oulu district of Ritaharju uses waste heat from refrigeration to meet its own needs and feed low-emission energy into the district heating network.
The solution, developed in co-operation with VTT Technical Research Centre of Finland, turns the S-Market supermarket into an efficient heat production facility that can heat 150 detached houses without much of a carbon footprint.
“The concept alters the entire business model,” stated Tuomas Paaso, project owner at VTT. “The supermarket does not buy heating energy. Instead, the district heating company invests in the equipment inside the market and agrees to buy the resulting energy while guaranteeing the supermarket the service it needs.”
S Group, the largest retail chain in Finland, has outlined plans to adopt the solution at altogether 110 of its supermarkets in a bid to bring down the markets’ district heating-related emissions to zero. The solution is to be initially adopted at 11 outlets in northern parts of the country given the high concentration of low-energy outlets in the region.
“I hope the solution becomes widespread,” said Klaus Känsälä, the father of the concept at VTT. “If the best technology is used by only some companies, this would be a loss to the entire energy sector.”
Arina Cooperative Association is one of the cooperative societies making up S Group and oversees the Ritaharju supermarket’s operations. Arina and VTT began developing new energy solutions a couple of years ago in order to improve the energy efficiency of retail outlets. Although the development work has already yielded results, the effort is continuing to come up with a solution for feeding heat into the return pipes of the district heating network.
Using the return piping is advantageous because it does not require raising the temperature of the heat to 90–95 degrees centigrade with a heat pump. A temperature of 40–45 degrees is enough, according to VTT.
“Companies are wondering where to get heat in the future,” noted Känsälä. “Possible solutions have included extracting heat from the sea, but using cold sea water with heat pumps consumes large amounts of energy. Taking part of the heat from the return pipes would lead to lower energy consumption.”
Paaso added that the solution also has potential for controlling energy regulating power and energy flexibility trading. A smart energy management solution, he explained, could enable using a district heating network as an energy storage or source of regulating power and, thereby, reduce emissions.
“This would make it possible to build a completely new energy community model that [benefits] both end-users and producers of electrical energy,” told Känsälä.