Tommaso Ferrarese - Carel Industries - SUPERMERCATI AD ALTA EFFICIENZA

XV EUROPEAN CONFERENCE MILANO 7th-8th JUNE 2013 CSG

Latest Technology in Refrigeration and Air Conditioning Under the Auspices of the PRESIDENCY OF THE COUNCIL OF MINISTERS

High efficiency supermarkets: BLDC compressors and waterloop

Tommaso Ferrarese – HVAC/R Laboratory, Carel Industries S.p.A. Giacomo Bagarella – PhD Energetic Engineering, University of Padua



Refrigerant leakages and power consumption in supermarkets

Refrigeration systemLightingHVACMiscellaneous

7%

18%

21%

54%

15%

20%

8%

36%

21%

MT compressorsLT compressorsAircooled condensersDisplay case fans/lightsDefrost & anti-sweat heaters

Refrigerant Charge

3.5 ÷ 4 kg/kW

Refrigerant leakages

10% ÷ 15%



Waterloop solution

BLDC compressor onboard, inverter driven

Condenser and inverter electronics are cooled by water

Electronic expansion valve

Reverse cycle defrost available

Inverter driven BLDC compressor allows flexibility, high efficiency in part load operation and optimal temperature control

No need of 3phase power supply for each cabinet. Heat produced during defrost can be recovered by the water loop

Stand-alone cabinet



Waterloop solutionWaterloop plant



Charge and leakages reduction

Leakage reduction: from 10%-15% to 1-2%

Charge Reduction over 70%:From 3.5 ÷ 4 kg/kW to 1 kg/kW



Energy efficiency

In traditional supermarkets suction pressure setpoint depends from «worst» conditions: maximum cooling power demand

A centralized system with floating suction can increase the setpoint when the cooling demand is lower, but it always depends on the «worst» unit



Energy efficiency

Each self contained cabinet can operate with the maximum evap T allowed

When load ratio is less than 1 the inverter compressor reduces its speed and works with a higher Evap T than in traditional systems



Costs

Stand-alone units are more expensive than standard onesCooling devices installed on the waterloop are standard

AC units, available on the market, reliable and operating in more efficient conditions

Copper pipes are replaced by hydraulic pipesNo need of pipe insulationCharge reductionMore flexibility in plant architectureHigh reliabilty due to factory assembled unitsRunning costs reduced by higher efficiency and easy

maintenance



Medium Temp

UnitsControl Devices

CpsCool.Cap.

[kW]Low Temp Units

Control devices

CpsCool.Cap. [kW]

Vegetables 2 2 2 3780Frozen

food6 6 6 9500

Dairy 6 6 6 20800 Cells 2 4 4 4200Meat 3 3 3 9700 Total 8 10 10 13700

Fish 2 4 2 2780Comp.

cool. cap.Evap T: -35°C Evap T: -10°C

Deli 6 8 3 9080 Small 800 2200Cold rooms 7 7 4 13600 Medium 1300 3600

Total 26 30 20 59740 Large 1700 4500

Real supermarket plant



Supermarket simulation

Data Acquisition

Energetic Model(Water-Loop

Solution)

RealSupermarket

Energetic Model(Traditional

Supermarket)

Condensation: FixedEvaporation: Fixed

SimulationsEnergetic Model(Advanced

Supermarket)

Energetic ModelR134a/CO2

Cascade

Weather Data(Berlin)

Cooling Loads

Condensation: FloatingEvaporation: Floating

Condensation: FloatingEvaporation: Floating Energy

Analysis

Energetic Model

Model Validation

Superm

arket Area 3000 m

2



Supermarket simulation

Medium Temperature

CabinetsCooling

capacity [W]Low

TemperatureCabinets

Cooling capacity [W]

Vegetables 6 10000 Frozen food 24 35000

Dairy 18 60000 Cells 6 20000

Meat 8 26000 Total 30 55000

Fish 6 8000

Deli 18 26000

Cold rooms 8 35000

Total 64 165000

MT/LT Comps

MT/LT Cool. Capacity [kW]

MT/LT Electric Power [kW]

MT/LT Evap T [kW]Cond T

[°C]Waterloop

solution72/30 170/60 79/34 Variable/Variable 20

Traditional Supermarket

6/3 200/64 87/53 -10/-35 33

Advanced Supermarket

6/3 200/64 87/53 Variable/Variable Variable

R134a/CO2 Cascade

7/3 270/78 100/22 Variable/Variable Variable

Reference



Supermarket simulationEnergy efficiency



Supermarket simulationEnergy efficiency

Energy absorbed

[kWh/year]Energy saved

[kWh/year]Energy saving

Money saving [€/year] MIN

Money saving [€/year] MAX

Waterloop solution BLDC

418500 - - -

W.loop fixed speed Comp

458200 39700 9% 5955 9925


592400 173900 29% 26085 43475


457000 38500 8% 5775 9625

R134a/CO2 Cascade

466000 47500 10% 7125 11875



Supermarket simulationTEWI

CO2 indirect [t CO2/10 yrs]

CO2 direct [t CO2/10 yrs]

C02 End of Life [t CO2]

TEWI [t CO2/ 10 year]

Waterloop solution

4425 72 36 4533


5469 19% 4560 98% 152 76% 10181 55%


4656 5% 4560 98% 152 76% 9368 52%

R134a/CO2 Cascade

4711 6% 936 92% 31 -15% 3764 20%



Thank you for your attention!

Tommaso Ferrarese - Carel Industries - SUPERMERCATI AD ALTA EFFICIENZA

Business

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