solar thermal radiant heating system

[xboxman]

Hi

i'm looking to buy a solar thermal radiant heating system for my office i have about 500 square foot of space i need to heat ... i have 2 solar air heaters that work great but i like the idea of the solar thermal radiant heating system because of the storage (maybe i can heat into the night ) .

i was looking at a site called kingsolar http://kingsolar.com/catalog/mfg/package/closed-ecl4.html

so i was wondering if any of you know whats the best brand to go with ?

i'm thinking a Closed-loop system as it gets below 32f in my area...and maybe use a Heater Baseboard or 2 like this inside my office (see link )http://kingsolar.com/catalog/mfg/other/rb750a5.html

i have a small heat pump for my backup heat when the sun dont shine

lets hear what you all think

thanks

[GaryGary]

Hi,

There are quite a few good collector manufactures out there.  I'd look for collectors that have been through the SRCC certification.  You can look up the performance of certified collectors here:

http://www.solar-rating.org/RATINGS/RATINGS.HTM

A blurb on hos to use the ratings here:

http://www.builditsolar.com/References/Ratings/SRCCRating.htm

List of manufactueres here:

http://www.builditsolar.com/References/Suppliers/SolarHeating.htm#FlatPlate

The SRCC certification means they have passed some punishment tests, and its also necessary if you want to get the tax rebate.

The King Solar page you referenced was for a domestic water heating system.  Space heating systems are similar, but with some differences.  I'd take a look here:

http://www.builditsolar.com/Projects/SpaceHeating/Space_Heating.htm

in the "Active" section to get more info on space heating systems.  There are some examples of the kind of system you want to do there.

Baseboard heaters are not the best match for solar heating as they take pretty high temperature water to get to their rated output, and solar collectors get less efficient as you try to heat the water to higher temps (the losses go up).

Radiant floor heating is the best match as it can use water all the way down to 85F or so.

I've got both solar air heating collectors and a solar water heating collectors in a system I use for space heating.  My feeling is that they both work well, but the water heating systems are several times more complex, more maintenance prone, and more expensive.  On the other hand, the water heating systems can store heat, which is difficult with air systems.  But, you might consider whether you can add some more solar air heating collectors and (perhaps) some more thermal mass.  With more thermal mass, the room will heat more slowly and carry more heat into the evening.  This might work well for an office space that does not need to be heated all night.

Gary

[GeeMac]

I have a simple neophite question about solar water heating. Does a system that is simple such as: as solar water heater some pipe to the house and a radiator of some sort, need a pump to move the water or does is circulate by itself using the heat generated to move the water?

[TomW]

Gee;

It is 4:30 AM and I am not up to a bunch of typing so here is the nutshell version of the answer:

Yes. it can circulate itself. As long as the collection panel is below the "radiator" it will move the liquid / air just fine [if slowly]. There are a couple of simple parameters you must meet but totally doable.

The process is called "thermosiphon" Try googling that and you should find enough information to make it clear and get you going.

Good luck with it

Tom

[GeeMac]

Thank you, young fellow. That is all I needed to know.

Your pal

The Geezer.

[GaryGary]

Hi,

Some thermosyphon systems here:

http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm#Thermosyphon

Gary

[xboxman]

thanks for the info Gary.

i think i will just add more solar air heaters as i dont want to get into Radiant floor heating ( i would have to re do my floor) .

i think i'm using to big of a fan on my air heaters ( i have 2 heaters hook together )now it may not be giving the air time to heat up... my temp out put is about 90 F when it's about 30's or 40's F out side .i'm not sure what my CFM's are as i took the fan out of an microwave oven :p

but i can feel the air from it about 10 feet away .

thanks

[GaryGary]

Hi,

The collector will actually run more efficiently with lots of air and a relatively low temperature rise.  This makes the collector run cooler and reduces loses out the glazing to the outside.  But, 90F air can feel pretty cool blowing into a room, so you may want to slow it down a bit.

Gary