Presentationsmaterial EFFSYS 2 dagen Investigations of Heat Recovery in Different Refrigeration System Solutions in Supermarket Samer Sawalha and Yang Chen Department of Energy Technology Kungliga Tekniska Högskola Stockholm-Sweden

Project summary Investigate whether CO2 is a good alternative solution for supermarket refrigeration-Combined cooling and heating analysis Investigate the heat recovery performance of the new system solutions –different heat recovery options System modifications and optimizations will take into account not only the cooling efficiency but also the efficient heat recovery according to the needs in the supermarket Presentationsmaterial EFFSYS 2 dagen

Analysis methods Field measurementsComputer simulation modellingExperimental work-CO2 test rig Presentationsmaterial EFFSYS 2 dagen

Detailed outline Field Measurement (two supermarkets) -MSc thesis work of Jigme Nidup, presented on June 17, CO2 parallel system solution with heat pump in cascade CO2 booster system with de-superheating Simulation models Refrigeration systems solutions CO2 parallel CO2 booster R404A/CO2 cascade NH3/CO2 cascade R404A conventional with sub-cooling Heat recovery solutions Fixed head pressure Floating condensing-desuperheating Cascade heat pump Presentationsmaterial EFFSYS 2 dagen

Parallel CO2 transcritical (TR1) Presentationsmaterial EFFSYS 2 dagen

Field measurement (TR2) Presentationsmaterial EFFSYS 2 dagen

R404A/CO2 Cascade (CC)

NH3/CO2 Cascade

R404A conventional with SC

Total COP comparison Presentationsmaterial EFFSYS 2 dagen

Total COP comparison in HR mode Presentationsmaterial EFFSYS 2 dagen

Medium and low temp. COP Presentationsmaterial EFFSYS 2 dagen

Field measurement (TR2) Presentationsmaterial EFFSYS 2 dagen

Total COP comparison-No condenser loop Presentationsmaterial EFFSYS 2 dagen

Ongoing and future tasks Estimate the heating capacities in an average size supermarket Calculate the annual energy consumption of all the solutions combinations in different climates Conclude the best refrigeration-heat recovery combinations for different climates Experimental validation of CO2 systems in heat recovery mode in laboratory environment Presentationsmaterial EFFSYS 2 dagen

Schematic of the CO2 test rig Presentationsmaterial EFFSYS 2 dagen

Experimental main task Overall system evaluation Heat exchangers evaluation Compressor losses and oil cooler capacity System control Presentationsmaterial EFFSYS 2 dagen

Conclusions Field measurements performed Simulation models for several systems built Test rig built and running CO2 systems have potential with: -floating condensing and recovering heat from de-superheating -connected to heat pump at the condenser loop Presentationsmaterial EFFSYS 2 dagen