Idiotically saving energy
By Brett - Tue, 08/26/2008 - 5:09pm.
The Globe has a few tips on making your home "green", like installing solar panels to make electricity to heat water to heat your home. Instead of, you know, buying solar hot water collectors? (the "tip" also fails to mention available tax breaks and loans, and is overly pessimistic about the return rate.)
Or, how about this brilliant advice to use space heaters? Maybe the Globe should search their own archives to see just how irresponsible that 'tip' is. It doesn't help to have an in-house photo by Suzanne Kreiter for the 'tip' that shows almost everything you're NOT supposed to do: the most dangerous kind of heater (radiant), in a bedroom, with combustible material (the bedsheets) clearly not 3 feet away from the heater.
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Geez
Once again, Brett, you're rambling about things you don't understand. That "brilliant advice" is just fine!
Just playin'. That picture is pretty much completely irresponsible. They might as well heat that room with a fire pit in the center of it.
About that space heater picture ... and solar hot water
I seem to remember that it ran with a story on how people in foreclosed houses didn't have the legally required heat because the banks were illegally trying to force them out. Certainly not a recent sort of model of heater!
That said, space heaters can be very safe and economical. We had some ancient baseboards in our basement bedroom. We disconnected them and brought in a new model space heater = less money, safer (has an overheat protection), and right up against where the disconnected baseboards are. When we had work done the electrician foolishly threw stuff on top of it while working above it - it shut off like it was designed to.
We also have newer, safer ones that use fans and have very much shielded elements. They never get too hot to touch, have overheat protection, and shut off if they tip more than 15 degrees from upright.
Most space heater problems occur when people use old pieces of crap. There needs to be an awareness to throw those things out and buy new ones - they aren't exactly expensive, and are much cheaper to operate than some old fire hazard.
We need to replace our 30 year old solar hot water panels, and upgrade the system. I can see why people would do the electricity to hot water route, because I am intimately familiar with the requirements of a hot water solar heating system.
First there are the panels. These sometimes have a system to tilt them as the day progresses = more complexity. There is also a glycol circulation pump system. Then a heat exchanger in a secondary tank, that transfers heat from the glycol to the water. That water is often too hot when another system pumps it into the hot water heater, so it goes into the hot water tank, and comes out through a special mixing valve to prevent scalding.
Oh, and somehow all this hot glycol has to find its way from the roof, through the panels, and back through the house to the basement via a circulation system of pipes.
Much simpler to generate electricity, run it into the house, and heat the water if you don't already have all of the piping. (although you'd best use gas for the hot water and use the electricity for the fridge). Then again, I suspect that the bonehead they assigned to do the captions got it all mixed up and didn't realize that these are apples and oranges here ...
Much simpler to generate
Yes, but also far less efficient and with far higher costs (both initial and lifetime). Solar thermal systems are typically about 70% efficient, while the best consumer-ready photovoltaic systems are about 15%. For a typical home-sized system, the cost of PV equip/install is going to be several times higher as well.
Of course once you've got it, PV is a lot more versatile - because you can do anything you want with the electricity. Make enough of it and you can even sell it back to the electric company! Solar thermal is pretty much a single purpose tech. But modern versions are getting really good at that one thing. And the pro-installed systems are often warranteed for up to 40 years. Most PV has a lifespan of 15 years tops.
Don't I know it!
Even though my house has been dubbed "the best solar location in Medford", I know that it would be very expensive to replace that gronked and ancient hydro set up with PV array that would do about half to two-thirds of our electron needs.
Meanwhile, on a 15F sunny day in the winter about ten years ago, I used to get enough hot water off the roof to do about five loads of diapers (we are talking HOT water here) before I would hear the hot water heater start up. That is a considerable amount of heat transfer given the external weather conditions.