I installed solar thermal heat on my workshop a year ago. Three panels, each measuring 4 feet by 10 feet. These plus thermal shutters on 4 of 11 windows on the building cut the heat bill in half compared to a year earlier.
This past fall i completed construction of a five panel array of solar thermal to help heat this house. The system has been running for all of a month but it looks like the reduction in heat bill will be significant.
Both systems heat a glycol-water solution which is passed through a unit heater (basically a car radiator in a box with a fan on it) to draw the heat out of the water and then the water circulates back to be reheated by the sun. No storage on either system at this time, but a storage tank is planned for the house.
The take-home message is that solar thermal IS a DIY project. If you can solder, perform basic wiring tasks and construct anything then you are probably skilled enough to install your own solar thermal.
Pete
This post was submitted by Peter Gruendeman.
Your right, with some caveats.
It would be nice to know what you’re climate is like.
Temperatures and pressures with solar water heaters can be lethal. You need to have a functioning pressure release!! Summer temperature in particular can skyrocket the temperature. You’ll need a way to dump heat at times like that - or drainback - or you’ll cook your glycol.
I’m partial to passive solar - using windows to collect the heat for free.
The really nice thing about solar water heaters is that they allow one to take the heat - but not have to deal with the energy loss of a windows.
A window is only about R3 (R10 with really good insulating shutters) while a wall is R20 or ideally R30.
It would be neat if you could document your system a bit more. Where are the collectors (roof? ground?). You insulated the runs into the house? What sort of pump did you use (choose the incorrect type and it’ll fail pretty soon!)?
Comment by Eric — January 27, 2010 @ 9:02 am
I’ve been tossing around the idea of building a “heat grabber” for a while now: http://greenterrafirma.com/solar-air-heating.html
I’m not great with power tools though so it’s a little bit intimidating. My boyfriend (the uber-geek) says that I’d have to be really careful aobut sealing the opening or I’d end up letting in more cold air than I am saving with the heat.
Any thoughts?
Comment by Rebecca — January 27, 2010 @ 5:02 pm
The solar thermal panels described at the start of this thread are at my house in western Wisconsin, at 44 degrees north latitude. They are on a ground mount, with the bottoms of the panels about 16 inches off the ground. They are tipped up 60 degrees from horizontal. This is to provide maximum solar gain during the winter months and equally important, to limit solar gain in the summer. This system is only intended to heat my shop space. No heat is needed in the summer so the panels are covered with heavy white plastic so they collect little or no heat.
It’s true that solar thermal collectors can endanger a person with heat and pressure. I know of people who have died with exposure to automobiles, bicycles, ethanol and one very serious injury due to a batted baseball. With suitable precautions all of these devices can be reasonably safe. With solar thermal that includes a reliable water pump and temperature controller to keep the glycol solution moving so it does not overheat in the panels. I use a Grundfoss ups15-58FC circulating pump. If the electricity was to go out on a sunny day the panels would get too hot. I would like to add a DC pump and a PV panel to at least keep the liquid moving enough to not overheat. I may instead use battery storage and an inverter. To be determined. An overpressure valve is in place, at the top corner of the panels.
Passive solar is popular in WI even though there are the occasional cloudy days and it is totally dark for at least 15 hours of every winter day. As commented above, it’s pretty tough to take in enough solar energy during the good days to overcome the R-3 losses. At least with active solar a R-19 wall is a R-19 wall without a major R-3 hole in it.
The link provided to homemade hot air panels shows panels made from wood. I am greatly concerned about the fire hazard presented by overly dried wood exposed to temperatures in the low 200 F range which will be reached when the circulating fan quits working. Insist on all-metal construction for projects like this!
Pete
Comment by Peter Gruendeman — January 30, 2010 @ 2:38 pm