Information & Computational Sciences

Fridge Freezer

By on 20/06/2016 in ICS

Over Hogmanay our fridge packed in. It had lasted for ages; it was passed on to us from my in-laws, and was at least twenty years old when it died. So, we had to buy a new one. There’s a danger in writing about one’s purchases of creating the impression that one is carefully hiding a boast. “Tsk,” some text might begin, “I had the most terrible time getting the colour I wanted for my new Bentley.” I trust, however, that a fridge-freezer constitutes a sufficiently mundane item that I am relatively safe in writing about buying one, fraught though the matter is with navigating the social statuses associated with different brands.

My motivation in sharing this episode derives from my involvement in the GLAMURS EU project, which is looking at ways we can transition to more sustainable lifestyles by learning from behaviours and practices in various ‘alternative’ small-scale initiatives. I have also been working with Tony Craig on the NESEMP project, funded by the Scottish Government, where we have put energy monitors into several people’s homes to get data on their long-term electricity consumption patterns.

Having had a personal interest in such things for several years, I have been a subscriber to Ethical Consumer magazine, which in one of its reviews of fridges, suggested that one could always keep food in a hole in the ground, because the temperature there is always cool. I imagine they were motivated for each of their reviews to show that there is an alternative to the gadget or appliance in question, but this is a little too alternative. The point is nevertheless well-made that before Fred Wolf invented the domestic refrigerator in 1913, we somehow survived without a piece of domestic equipment that is now by-and-large taken for granted as being a part of everyday life.

Even if it is given that a household will own a piece of refrigeration equipment, there is a considerable choice of appliances available. Further, since it is on all the time, it constitutes a commitment in terms of energy comprising the product of its life-expectancy and energy consumption. Appliances are not built to last as long as once they were, but assuming a new fridge will last 10 years, every 100kWh of energy it uses per year adds 1MWh to its lifetime demand.

There is a huge choice of refrigeration equipment, from small worktop devices and drinks chillers to ‘American’-style fridge-freezers so large that when you open them you half expect to find Narnia under the rule of the Snow Queen. These all range in consumption from about 100kWh per year to 500kWh, so the choice does make a significant difference to the base load of a house. In the EU, this information is conveyed using the energy label.

The European Union’s energy labelling system is supposed to convey information on energy efficiency using a grade, from A to G, where A is the most energy efficient. Improvements in technology since the scheme was first introduced in the nineties means that changes have been needed. I don’t know how you would feel if your child (if you have one) came home from school saying they got an A+ today. To me, it sounds pretty good. But since July 2012 in the world of refrigeration, A+ has been the lowest grade appliance manufacturers have been allowed to market in the EU. (Retailers can still sell A and B rated models from old stock.)

The energy ratings of fridges on the market are therefore B, A, A+, A++ and A+++ in ascending order. The advantage of a grading system using just letters is that you know that ‘A’ is the best. Once you start adding pluses in, you don’t automatically know what the best is, and let’s face it, when choosing a fridge, freezer or fridge-freezer, you will have other criteria on your mind than the energy efficiency rating. Interestingly, when I went in to a popular high-street electronic goods store in Aberdeen recently, all of their goods were A+ rated. It is not difficult to imagine customers being told that the A+ rating means the energy efficiency is dealt with, allowing them to concentrate on all the features they are really interested in (or can be made interested in by the salesperson). George Monbiot has been scathing on the subject.

The energy efficiency calculation that determines the grade is not a straightforward computation. In fact, it is the ratio of the appliance’s estimated annual consumption to a ‘standard’. To get the highest rating, an A+++ rated appliance needs to have an efficiency better than just over a fifth of the ‘standard’. This standard depends on the type of appliance, the number of compartments, whether it is frost-free and whether it is built-in. These parameters have a large effect on the grade. For example, a fridge-freezer can use more three times the energy of a larder fridge and still have the same grade. Each frost-free compartment allows you another 120% on the annual energy consumption, as does being built-in. This is probably why the Energy Savings Trust’s advice when buying refrigeration equipment is to compare the annual energy consumption that is displayed in the bottom right of the energy label.

The same store I walked in to has a wider variety of appliances on sale on its website, some of which have better than A+ ratings. So, it would seem that if you are concerned about energy efficiency, you need to shop online. And here is where the interesting computer science comes in. Most data you see online is stored in a database from which information is extracted using the Structured Query Language (or SQL). SQL is a fourth-generation language; first generation language is very low-level computer code, and in general, the higher the generation of the computer programming language, supposedly the easier it is to understand and work with. When I did my Artificial Intelligence degree a quarter of a century ago, we were being taught fifth-generation programming languages by excited lecturers who thought we would one day (soon) write computer programs in English. I can now talk to my mobile phone in English, which is very impressive, but the answer I get to, “Which fridge-freezers use less than 200kWh per year?” is a list of webpages, mostly discussing the energy label, not a list of currently-available appliances.

Searching databases using their native language rather than yours is therefore still a specialism. To get round this, website developers have to provide an interface on the webpage from which they can construct the database search SQL you want using options you have selected on the interface. This mostly consists of a set of filters with pre-defined options. The website of the store I visited has a large number of filters, including price, brand, customer rating, energy rating, capacity, number of drawers, and even colour. What it doesn’t have is a filter for annual energy consumption even though this information is in the database as it is displayed in the technical specifications. Neither does any other on-line shop I looked at, which means I can’t search for it. Energy rating may give me rough guide, but the formula for energy rating has so many terms that depend on appliance features, that it is no longer a particularly good guide of energy efficiency.

Following the advice of the Energy Savings Trust almost requires you to compile your own database, which I expect is more effort than most people will be prepared to take. I finally managed to find an A+++ fridge-freezer with a 176 kWh estimated annual energy consumption, which impressively is less than my A-rated freezer alone. However, with the recent VW scandal in mind, how trustworthy is that estimate? I connected a dedicated energy monitor to the new fridge-freezer, and the mean daily consumption over a period of just over 28 days (most of which were in March) was 0.45 kWh, which, if maintained year-round is pleasingly a little under the official estimate. Although some allowance is needed for the 28 days in question not having been in the summer, when refrigeration equipment has to work harder to keep things cool, it really does seem that the appliance has the advertised energy efficiency.

Positive though this outcome is, if this story says anything about the prospects for transitioning to a more sustainable Scotland or Europe, it is that in even such a trivial everyday practice such as refrigeration, several stars have to align for there to be any chance of success. First, consumers need to care about energy efficiency. Regulations on energy labelling need to maintain ‘A’ as the best, so that consumers who care can quickly rule out less efficient options. The high street needs to provide a choice that includes the most efficient options for those without access to the web. Web interfaces to stores online need to provide tools to conduct appliance searches using the EST’s recommended criterion. It would seem we have a lot to do if we are really going to achieve the changes in lifestyle needed to live sustainably.

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