1. Utilizing Excess heat from a Supermarket Refrigeration System in a District heating Grid as part of a Smart Energy System
XIX INTRNATIONAL CONFERENCE ON DISTRICT ENERGY
Portoroz March 2016
Jan Eric Thorsen
Danfoss A/S Heating Segment Application & Technology
Torben Green, Torben Funder-Christensen
Danfoss A/S Cooling Segment
Denmark

2. Content Supermarkets as smart appliance Flexibility in supermarkets
Aggregated potentials
Thermal networks
Case study on District Heating connectivity
Unused compressor capacity is an opportunity
Conclusion
This presentation is about the smart grid opportunities for a combined heating and refrigeration cycle applied in food retail applications.
The potential of adding the flexibility of supermarkets to a smart grid network is outlined as well as the potential of utilisation of unused compressor capacity. In connection with external thermal networks a functional storage opportunity for renewable energy sources like wind is shown viable and backed up by a new case study. The business implications of connecting the supermarket to the district heating are briefly outlined.

3. Supermarkets as a smart appliance
Exploiting flexibility is doable without big investments
The existing retail service structure is perfect to leverage on
Exploiting flexibility is doable without big investments
The existing retail service structure is perfect to leverage on

4. Flexibility in supermarkets

5. Flexibility characteristics

6. Aggregated flexibility potentials
Supermarkets use up to 2% of all electricity use for compressor
corresponding to 10 TWh in GER, 2012, outlets, 32 mill. m^2
Flexibility of multiple supermarkets can be aggregated, and adressable
Total supermarket aggregation in GER would account for
> 15 % of average delivered wind power (57,4 TWh/2014) in GER
> 25 % of average delivered PV power (36,1 TWh/2014) in GER

7. Thermal networks expand the perception of smart systems and the scope for supermarkets
“Waste” or excess heat and cooling from refrigeration can be exported
Supermarkets can add flexibility and become storage enablers for heating and cooling

8. In the perspective of DH development
District heating networks can absorb and store fluctuating energy
Typically only 30% of the total compressor capacity is used
Assumingly a factor 2 more energy can be produced with external heat sources

9. Case study on District Heating connectivity
Southern Denmark
Area: 1000 m2 from 2010
Compressors: 5 MT (1 VS), 4 LT
Cooling Capacity: 160 kW
Online COP calculation
Heating :
Sanitary water (1.8m3 ,65 oC)
Space heating/low temp (35 oC )
District Heating connection
Flow line temp. 65 oC
Return line temp oC
Online COP to ensure that only real waste heat is produced

10. Outline of system concept
DH from return line
DH to flow line
Space heating water loop

11. Results The heat loss is 65 % of the total heat energy
The heat loss is expected to be 35 % when space heating cut in at low ambient temp.
Average export of DH heat is 27 kW at 65 °C . (This can be regarded as an average for the year, Summer ~40 kW / winter ~15 kw)
Yearly DH income to the supermarket is estimated to be 6000€ (24€ per MWh)
Accumulated Energy exported to the DH grid
MT cooling contains LT energy. But it not contain the MT compressor energy.
MT + Compresso energy will be approx. 1,3*78 = 101 kW
DH heat + Heat loss to ambient is = = 95 kW.
Difference is heat lost in machine room + small amount of space heating (T-amb was 8 degrees in week 15 in SDBG airport)

12. Conclusion Supermarkets:
can play a significant role in smart and integrated energy systems
are addressable flexibility resources
require modest investments before they make up a good business case
Heat recovery is taken to the next level by connecting DH grids to the supermarket refrigeration system
Extended heat and cooling production can be utilised once connected to the DH grids
Thermal and Electrical Flexibility can enforce each other providing a multiplier factor for the business case

13. Thank You for the attention Jan Eric Thorsen jet@danfoss
Thank You for the attention Jan Eric Thorsen Danfoss A/S Heating Segment Application & Technology