Posts Tagged ‘energy conservation’

With refrigerators, bigger is better in more ways than you think

Wednesday, June 19th, 2013

High end: a 603-liter refrigerator with a five-star rating and 244 percent energy efficiency that uses ¥5,500 of electricity a year

High end: a 603-liter refrigerator with a five-star rating and 244 percent energy efficiency that uses ¥5,500 of electricity a year

Over the past decade or so our diet has changed slightly. We almost never eat meat at home and have gradually eliminated most dairy products. Consequently, the volume of food in our refrigerator has decreased over time, and since we bought it in 2002 it is already considered obsolete, inefficient even. Refrigeration technology has improved markedly in the past 10 years to the point that devices made now use as little as one-fourth the amount of energy used by an equivalent sized refrigerator made in the ’80s or ’90s. And since we are contemplating moving sometime in the future we decided it might be a good idea to buy a new, smaller model when we do in order to take advantage of this greater efficiency.

So we went to our local discount electronics store and looked at all the models. Of course, smaller refrigerators cost less than larger ones, but when we looked at the energy consumption specifications we became confused. The bigger the volume of the refrigerator, the less energy it used. In some comparisons the difference was startling. If you look on the inside of the main compartment door of a refrigerator there is a sticker with the pertinent specifications, one of which is the average amount of kilowatts the appliance uses in a given year when operating continuously. We saw one 500-liter model that used only 40 percent of the energy that a 350-liter model used. The manufacturers make the comparison even easier by printing the average amount of money you will pay in electricity for a year on the outside of a given model. Moreover, there are star ratings, from one to five, that indicate energy efficiency in relative terms, with five stars indicating the most efficient.

We asked a salesman if there was a smaller refrigerator that was as efficient as a large one and he quickly said there wasn’t. The difference he said was that larger refrigerators used inverters to control the operation of the compressors in a smoother fashion, while smaller refrigerators used conventional compressors that simply went on and off to control interior temperatures. The inverter, however, also makes the refrigerator itself more expensive. When we said our present refrigerator was 415 liters and that we wanted something smaller, he said rather presumptuously, “I can tell you which size you need.”

Since we aren’t newlyweds and found his manner condescending we decided to look into the matter ourselves. The star system is administered by the Energy Conservation Center of Japan, a government organ, and is based on the energy savings achievement rate (sho-ene taseiritsu) established by the 2006 Energy Conservation Law. The unit used for comparison’s sake is Annual Performance Factor, a means of measuring energy efficiency. In order to come up with an efficiency rating, the ECCJ currently uses “the most efficient product” on the market in terms of energy consumption in 2010. The efficiency percentages on the store sticker are based on APF and thus only indicate relative values. For instance, an energy efficiency finding of 110 percent means that the model is 10 percent more efficient than the 2010 model chosen by the ECCJ as the standard, and which is not publicly disclosed. The stars are more or less a means of making these comparisons even easier. However, comparing refrigerator prices against money saved on electricity bills may require a certain algebraic capability that most consumers don’t possess or, if they do, probably don’t want to bother with.

Conventional compressors, which use electricity and chemicals to cool the interior of the refrigerator, turn off when the desired temperature is reached and then turn on again when the temperature rises above that level. It takes a lot of energy to turn a compressor on. The inverter works on a kind of fuzzy logic principle. It keeps the compressor working all the time but at variable levels, using less energy in the process. It also produces much less noise since conventional compressors tend to get loud when they start up again. That’s why an older refrigerator, or a smaller new one, suddenly kicks into high gear whenever you open the door. An inverter will add at least ¥20,000 to the price of a refrigerator, and according to one website we saw electronics manufacturers don’t think people will buy smaller refrigerators if the price is above a certain threshold, so they don’t bother putting inverters in them.

Of course, some people simply think that the small-big energy-saving paradox is a scheme by these manufacturers to compel consumers to buy refrigerators that may be too big for their homes or their needs, since profit margins rise almost exponentially with the price of the unit. If that’s the case then it seems to be working. Last year, the only household appliances whose recycling rates increased were air conditioners (up 0.8 percent) and refrigerators (2.7 percent).

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