Thermoelectric Cooler 2

I’ve been running the thermoelectric cooler (prior post) steadily for a significant fraction of a day, and measuring its power consumption and the temperature difference. It uses about 1.0 kilowatt-hour per day of power (from the wall outlet, via convertor to 12V DC). That costs about 25 cents US. The temperature difference maintained is about 13.3-13.5 degrees C.

Perhaps I should elaborate on that 25 cents per kwh figure. When I take my electrical bill, and look at the power actually used (before markup of quantity by about 9 percent for transmission losses), and divide that into the total charge (inlcuding various service charges, etc), it is about 22 cents Canadian, or 20 cents US. However, a couple of decades ago when I was reading a lot about solar power alternatives, especially for off-grid situations, a figure was offered that if you were on-grid, local solar generation would be an economic break-even if the grid charge was about 25 cents per kwh. Considering capital costs, etc. Thus I’ve taken to using 25 cents/kwh as my guideline for evaluating the economic cost or value of a kilowatt hour of electricity, however produced.

There are always other considerations. But it’s nice to have a rule of thumb, so that one does not have to get into some complicated calculations when a simple Yes/Maybe/No question is being asked, and if the answer is Yes or No then the action to take is simple. It’s mostly the Maybe answers that require a further detailed investigation.

Best wishes,
Ken Roberts
28-Jun-2014