COOL RUNNINGS
WHAT TO LOOK FOR
ACCURATE and useable fridge controls are important for setting and maintaining a temperature, but most temperature readouts on these fridges are not calibrated, so they are not 100 per cent accurate. We found this be true, with temp readout variations from -1°C to 7°C, even though all fridges were set at 3°C – clearly, what the digital readouts are telling us is not what the actual temps are inside the fridge.
Instant power use means little. Instead, it’s how a fridge keeps its contents within a set temperature range that matters. Power usage is variable and depends on ambient temperatures, humidity, the amount of food in the fridge and the regularity of lid openings. We may all want to use as little power as possible, but my bet is that most people would be willing to sacrifice a little extra power usage knowing that their fridge will do the job long term.
Other than a good power supply and correct wiring, the most important thing to keep any fridge running effectively is ventilation around the compressor. There should be ventilation on the sides and top of the compressor, as well as a fan to expel the hot air the compressor creates.
Watch out for condensation (or excessive coolness) in small sections of the fridge’s exterior. This proves a lack of thermal insulation qualities, which equates to a loss of cooling effectiveness and leads to excessive power consumption.
Look at the position of the evaporator plate in the cabinet – the higher it goes in the cabinet (a gap between the plate and the base of the fridge is okay) the better the all-round cooling will be.
A separate evaporator plate (in the fridge cabinet) should work better than an integrated one, as both sides of the plate can supply cool air to the inside of the fridge. A slight convection current around the plate can also help circulate cold air, but that separate evaporator allows liquid, food and dirt to build up behind it. A
separate evaporator can also be damaged more easily than an integrated one.
Other key areas to look at include the lid seal; good insulation to help reduce compressor run-time; tie-down points; low battery voltage protection; and power options (12-, 24- and 240-volt). Fridge covers may have minimal thermal advantages, but they are a good option for protecting a fridge’s exterior and for keeping direct sunlight off the unit. Covers are more useful on metal fridges compared to plastic and fibreglass units.
COMPRESSORS
DANFOSS was a German-designed and manufactured hermetic-piston-type compressor, which arrived in 1977. It has since been copied, duplicated and counterfeited by various countries and organisations around the world.
These days the German Danfoss brand is no more – it was acquired and its name changed to SECOP in 2010. It’s still the same (or similar) unit with the same (or similar) models (BD35 for smaller and midrange fridges; BD50 for the larger ones) with company headquarters in Germany, albeit with manufacturing in Austria, Slovakia and China. In 1998 the variablespeed compressor was created, whereby the electronics of the fridge manufacturer could control the compressor speed to aid in lower power consumption.
While most of the fridges on test have a SECOP BD35 compressor, the Engel has a Sawafuji unit, the WAECO fridge utilises a Waeco-branded compressor and the Opposite Lock fridge has gone with the Snomaster compressor.
The Snomaster compressor is used in both of Opposite Lock’s fridge sizes (40 and 72 litres) in Australia. It was designed to return faster pull-down temperatures via its higher power, as well as short cycle times in combination with good thermal cabinets. Our testing confirmed this compressor is the standout.