A LOW CARBON DEFROST SYSTEM

PowerPoint Presentation

A LOW CARBON DEFROST SYSTEM Tom DAVIES , Robin CAMPBELL, Varun THANGAMANIFrigesco Ltd., Innovation Centre, University of [email protected] Intnl Refrigeration and Air Conditioning Conference, Purdue, 2014EXISTING DEFROST METHODS ElectricHot gasCool gasWarm liquidReverse cycle

ALL USE EXTRA ENERGY TO MELT ICE AND THEN TO RE-CHILLSome use thermal storage2FLASH DEFROSTREQUIRES A HEAT STORE INSERTED IN THE LIQUID LINE LEAVING THE CONDENSERREQUIRES 3 SOLENOID VALVES + PIPEWORKDOES NOT USE EXTRA ENERGYNORMAL OPERATION & HEAT STORE ON CHARGE

SUBCOOLING DURING CHARGE

START OF DEFROST

EVAPORATOR TEMP DURING DEFROST

HEAT STORE DEPLETED

HEAT STORE RECHARGEDPOSSIBLE COLD CHAIN APPLICATIONSLARGE SYSTEMS WAREHOUSESTRANSPORT SYSTEMSSUPERMARKETS AND CONVENIENCE STORES WALK-INSRETAIL DISPLAY CABINETS (RDCs)DOMESTIC FREEZERS______________________________________________PLUSAIR SOURCE HEAT PUMPS

TESTS ON:

Supermarket retail display cabinets - 4.8m worldwide.

Cold Rooms - over 2.5m worldwide, 900k in large supermarkets, 300k in fast food (MacDonalds, Starbucks, etc) plus hospitals, schools, restaurants.

Air source heat pumps, rapidly growing market. Over 2m units sold in Europein 2010.

RDC TESTS2.6m HALF GLASS DOOR PLUS OPEN WELL (R404A)BOTH REFRIGERATION CIRCUITS MODIFIED TO TAKE HEAT STORE MODULESCOULD BE RUN WITH EITHER ELECTRIC DEFROST OR FLASH DEFROST24hr TESTS TO COMPARE ENERGY CONSUMPTION TO EN23953:2005 STANDARD AT CC3.FLASH DEFROST REDUCED ENERGY CONSUMPTION BY 40% WITH 6 DEFROSTS PER DAY.

RDC TESTS AVERAGE PRODUCT TEMPERATURES

WALK-IN TESTS 8m3 STOREROOM WITH SIMULATED LOADSREFRIGERATION CIRCUIT MODIFIED TO TAKE HEAT STORE MODULE (R404A)COULD BE RUN WITH EITHER ELECTRIC DEFROST OF FLASH DEFROST24hr TESTS TO COMPARE ENERGY CONSUMPTIONFLASH DEFROST REDUCED ENERGY CONSUMPTION BY 20%

ELEMENTS OF WALK-IN RIG

WALK-IN TESTS PRODUCT TEMPERATURE SWINGS

DAILY ENERGY CONSUMPTION RDCElectric defrostFlash defrostDEC (KWh/24h)52.2631.87RECRC (KWh/24h)66.6639.03TEC (KWh/24h)118.9270.90WALK-INElectric defrostFlash defrostTEC (KWh/24h)360288BENEFITS OF FLASH DEFROSTFlash defrost eliminates the use of electrical power for melting iceFlash defrost limits the temperature rise in the air coilFlash defrost reduces temperature rises in the productFlash defrost reduces energy consumption in post-defrost re-chilling phaseFlash defrost creates the opportunity to operate at higher evaporator temperaturesFlash defrost allows more frequent defrosts

Questions?