Saturday, September 23, 2006

The Ice Man Cometh?


The energy meter that I fitted to my fridge and freezer a year ago shows a consumption of 569 kWh in the last year - a little more than 1.55kWh per day, or 19.2% of my total consumption.

I reckonned that this was a little high, so I watched the energy meter a while and noticed that the freezer was taking a continuous 50W, instead of cycling on and off.

I suspected that it was time for a defrost, so that the cooling coils can work more efficiently. A couple of hours spent with some hot water in baking trays soon had the freezer completely ice free!

At the same time I turned down the freezer thermostat from 5 to 4, as clearly the freezer had been running very cold.

The strategy worked and the fridge/freezer daily consumption has halved, resulting in an overall 10% saving in my electricity consumption.

It's now a year since I started my "E-Plan" electricity diet, there have been some successes, some failures, and plenty of room left for improvement.

My Excel Spreadsheet, of meter readings tells me that I have used 2954 kWh of electricity in the last 365 days, which is an average of 8.1 units per day.

The main problem has been remembering to turn off devices at the end of the day, particularly those with clocks, such as the microwave, which over the course of a year will use about 27 kWh - keeping its clock running!

Also the TV in the bedroom is always on standby drawing 3.5W - another 30kWh per year.

One of my pastimes is listening to the radio whilst I work. There is always something intelligent to listen to on BBC Radio 4, and it helps pass the time, whilst working alone from home. This morning I discovered that my mini-HiFi had a standby current of 6W, and only 7W whilst playing the radio - perhaps its time to re-instate my solar/clockwork radio.

One other revelation was that the power supply for my solar panel circulation pump, that comes on for 8 hours per day on a timeswitch, was using 25W doing nothing and 28W when pumping. I have now replaced it with a plug-in supply that uses just 7W whilst pumping. This will save at least another 52kWh per year.

My workroom/Office is central to everything I do, and has it's own power budget. Some time ago I speculated on the "200W Office", and this is something that I have tried to adhere to. As the Office is powered for nearly 18 hours per day, it is essential to keep the parasitic loads to a minimum. Typically it runs at around 175W, during the day and 200W when I need extra lighting.

One shocking fact, is that when I do turn off the PC at the end of the day, the Office is still drawing 20W of power keeping things on standby. This situation must be remedied and I am going to fit a master switch to the office, allowing everything to be turned off overnight.

Having totalled up all of the parasitic loads, i.e. things that consume power yet do nothing useful, I found that they were consuming 206 kWh of electricity per year - exactly 7% of my annual electricity consumption. To put that into perspective, that's enough electricity to heat my hot water for 30 days.

Having completed a year of the diet, I am eager to make further improvements, and see if I can get my consumption down to just 7.5kWh per day, by remembering to habitually turn off the unwanted devices.

Watch this space.

1 comment:

NiC said...

After getting an energy meter (after reading your blog a few months ago) and finding similar standby problems, I've fitted timers to some plugs (thus TV, cable box, vcr, dvd player automatically get turned off at midnight every night). I know this plays havoc with some vcr timers but ours seems to reset itself.

Thanks for the inspiration! :)