New calculation model – An accelerator to promote the utilization of recycled heat

The Super Supermarkets project is now complete. But the end only marks the beginning of far better utilization of surplus heat from Danish supermarkets. The purpose of the project has been to develop, demonstrate and verify best practice in heat recovery from supermarkets, so that the project can form the basis for much greater realization of the potential for surplus heat from supermarkets.

In the project, a number of tools have been developed to make it easy for supermarkets and district heating companies to develop new surplus heat projects together. The most important tool is the project’S COOKBOOK, which describes the experiences gathered by the project partners during the design, contract design, implementation and validation of demonstration cases, where three supermarkets have been converted for heat recovery. THE COOKBOOK can be downloaded HERE

Another essential tool developed in the project is a calculation model. The purpose of the model is to make it easy for supermarkets across the country to get an estimate of the economy of heat recovery in their particular supermarket. The calculation model is not detailed enough for an actual investment basis, but can instead form the basis for a decision to start a design work.

The calculation model is freely available to anyone interested on the project’s website.

The calculation model estimates the economy for three scenarios for heat recovery:

• Concept 1: Self-sufficiency. The supermarket itself produces all heat for own consumption for heating and hot water. This is achieved by, if necessary, raising the operating pressure of the refrigeration system.
• Concept 2: Self-sufficiency + sale of heat. The supermarket produces heat for own consumption, but when it is economically interesting, production is increased so that heat can be sold to the district heating network.
• Concept 3: Self-supply + sale of heat + heat pump operation on available compressor capacity. In addition to Concept 2, available compressor capacity is activated to supply heat to the district heating network. This heat production takes place as pure heat pump operation, ie not in co-production with cooling. This mode of operation can be equated with the district heating plant itself having to invest in heat pumps for heat production.

The calculation model has been tested on eight calculation cases with widely differing operating conditions and price levels. The results of the calculation cases as well as the calculation model with entered data for each case can be found HERE.

In the calculation cases, the Ministry of Taxation’s draft new tax rules for heat recovery in 2021 have been used. In the calculation model, tax rates and calculation methods can be easily changed so that other tax scenarios can be calculated.

Despite very different district heating prices, store sizes, etc., the eight calculation cases show really good business in establishing heat recovery for almost all the stores. Below are estimated simple payback times for the eight calculation cases. Establishment subsidies in the form of energy saving subsidies have not been included in the calculations shown.

The project is funded by the Danish Energy Agency’s EUDP program

Lotte Gramkow from CLEAN has been the project manager, and Frank Iversen from CLEAN has, with input from TI, prepared the calculation model in the project.

“Danfoss, Coop, Dansk Fjernvarme, OK, Teknologisk Institut, ILK, Dansk Fjernvarme Projektselskab, AK-Centralen, KTH (University of Stockholm) and three district heating companies (Kerteminde Forsyning, Gudenådalens Energiselskab and Fjernvarme Fyn) participated in the project.”