Sunday, July 20, 2008

We're In HOT Water

No we're not in trouble - at least as far as we know, but we do have a lot of hot water at our fingertips thanks to our solar hot water system. I've even had to adjust the balance on the system because we're making so much of it.
In response to a couple of requests, I'll do a bit more explanation of our solar thermal domestic hot water system. That's quite a mouthful for something that makes hot water for our household use.

Here's how it works:

Solar Collectors are mounted on the roof. Piping runs through the solar collectors and down into a storage tank. Inside the piping is a glycol solution that picks up heat when running through the solar panels and sheds heat when it gets to the storage tank (The pipes are full of hot glycol. The hot pipes make the water in the tank hot). The hot water, when it's hot enough, goes directly to our showers, baths, sinks, etc. If it's not, it goes to our back up water heater (the water heater that came with the house) and gets brought up to temperature. Sounds so simple you'd think a code inspector would understand it right? Well, I suppose that's another story for another time.

Right now, our water is plenty hot. This winter, I expect the water heater will have a little work to do, though not nearly as much as it's had to do in the past.

Our solar panels are Solar Skies SS-32 Flat Plate Collectors, 4'x8' mounted at 45 degrees. We mounted them "landscape" rather than the traditional "portrait" to reduce their profile. Mario of Best Power International custom designed this system and improved the way the piping works in this type of installation. We're getting higher efficiencies and a much sleeker aesthetic. It's pretty dang sexy.
The panels have anodized aluminum frames, low iron textured glass and a high efficient nickel-chrome selective surface copper absorber. All of these things increase solar energy transmission - making them more efficient.

Our Solar storage tank is an 80 gallon Rheem HE Soleraide tank (in addition to our 40 gallon water heater - so we have 120 gallons of superbeautifulandwonderful hot water when we want it.

The system also has an expansion tank, a controller, sensors and a Caleffi Pump assembly.

The pump and valve system essentially manages and controls water temperature. It brings in cold water when it needs to or sends the warm water to be made hotter in the existing water heater. (If the existing water heater hadn't been a fairly new, energy efficient model - we'd have done a different kind of combination system.)


Mike said...

Wow - good on you. I've been toying with at least the idea of doing the same thing - I have the perfect pitch and angle on the south side of my house - but I've been put off by the fear of commercial viablity - finding someone in Michigan to do it, and, that someone trying not to make their entire's year income off of one job.

I'd like to do this to heat my boiler and heat my home. I'll be spending about $2k on propane this year. I need to make an investment in a new boiler, but I've been putting it off.

What can I expect a system like this to run, and what do you predict your return on investment is (if that's your concern).

thanks so much, this site has been a great help with ideas and concepts.


Kevin & Roxanne said...

Mike - Have a look at an earlier posting in June - A Roof Full of Energy - and you'll see costs associated with both the Solar hot water and the PV systems.
Not knowing houw big your home is, or how well insulated, type of windows etc, I can't tell you how big your system will need to be to heat your home. My guess is that you'd need 4-6 solar collectors + the tank, etc. I'd expect the price for that size system to be in the $9,000 range, installed. Check with your state dept of commerce to see if they have any rebate programs available as well as a list of solar installers. Talk to a few folks, get bids, and go to work. Solar Thermal systems are pretty affordable compared to solar pv.