Super Supermarkets-Better utilisation of surplus heat in supermarkets

Location: Different cities of Denmark

Population: N/A

Climate: Oceanic

Duration: 2016- 2019

Sector: District energy

Funding sources: Public

City networks: C40

Savings: Savings can be achieved by reusing the heat from the refrigeration system, but they can also be made by using electricity consumption intelligently.

Solutions: Better utilisation of surplus heat in supermarkets.

Multiple benefits: Heat recovery and store’s heating bill reduction.

A significant fraction of a supermarket’s energy consumption is used for refrigeration and frost. This is done by removing ambient heat to assure the goods’ durability. There are several possibilities for collecting and reusing this heat. This is because the heat has already been paid for in electricity.

Objective –  Super Supermarkets project aims to examine, demonstrate, and apply the full potential of available but untapped district heating production and system services in Danish supermarkets.

Solutions – Basic heat recovery has been implemented in around ten Danish supermarkets. This technology will be optimised and standardised as part of the Super Supermarkets initiative, including two more levels of energy system integration.

The first level uses excess compressor power (400 MW) in supermarkets as heat pumps for direct district heating generation. The second level is to use the opportunities for flexible electricity consumption in supermarket cooling systems to report system services in larger groups, e.g., regulating the power market.

The project will compile the most relevant findings and analyses from previous and ongoing research projects on optimising refrigeration systems in supermarkets, demand-side flexibility for power consumption in supermarkets, and heat pump installation in district heating systems (source).

Funding – € 640,000. The project is supported by EUDP and contributes to fulfilling the Danish climate and energy policy goals (source).

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Innovation – A calculation model for calculating the potentials for heat recovery for each supermarket has been created as part of the Super Supermarkets initiative.

The model’s goal is to make it simple for supermarkets around the country to determine the economics of heat recovery in their particular supermarket. The calculation model can serve as the foundation for a decision to begin design work. The developed model considers general and local conditions (i.e., supermarket’s cooling system) and offers an overview. More info here.

Success factors – 1) Utilising surplus heat from the stores’ refrigeration systems and supplying it to the district heating network may be an economic and environmental advantage for both supermarkets and district heating companies; 2) The Super Supermarkets project has also brought together a powerful project group that ensures both the highest level of knowledge in cooling and heating systems, as well as the market’s most important players in the field; 3) The project partners have been – or are – involved in all relevant research projects in this area, and thus have access to the most up-to-date knowledge in the areas (source); 4) The supermarket and the heating business agree on the heating price. However, the price agreement is subject to the substitution principle, which states that the price cannot be higher than the cost to produce or buy heat elsewhere by the heating company; 5) Repayment time. The store’s heating bill can be decreased by recovering heat from the refrigeration system. Besides replacing the store’s own purchase of gas, electricity, or district heating, surplus recycled heat from the refrigeration system may be sold to the district heating network; 6) Purchase of electricity in the spot market. Savings can also be made by using electricity wisely. By following the electricity market (spot market), you can save up to DKK 100 per day by switching off the cooling system during expensive hours and using a little more electricity during cheap hours. The spot market projection is viewed a day ahead.

Significant outcomes

• Savings on the store’s heating bill;
• Recycled heat.

Synergies with local policies:

• N/A

Political alignment:

• Denmark´s National Energy Efficiency Action Planpoints to a long-term objective that in 2050 energy supply will be entirely based on renewable energy. Moreover, according to the agreement, Denmark will reduce its total energy consumption by 7% during the period 2010 to 2020;
• Energy Agreement 2018 focuses on renewable energy, energy efficiency improvements, and research and energy regulation. The agreement provides for significant investments to realise the ambition of a low-emission society by the year 2050;
• Building Class 2020 aims to reduce the energy consumption of buildings by 75% compared with the 2006 level. It was introduced as a voluntary building class relatively early in the building regulations [source].

Marketability:  Some general framework parameters determine the profitability of heat recovery and a wide range of local factors. Local factors such as the supermarket’s cooling system, current heating system in the store, flow temperatures of district heating network, and production units are the economic basis for heat recovery.