Hydronic radiant heating?

gascort · 10-18-09, 08:48 PM

Anyone made a DIY hydronic radiant heating system? Maybe one that uses solar energy?
Simply Radiant | Extreme How To, DIY - Do it Yourself, Home Improvement, Home Decorating

I was thinking it could be added to my house; we have exposed joists in the basement ceiling, could use PEX tubing run back and forth under the floor there; would heat the basement below and the floor above.
I want to ecorenovate our roof using builditsolar - style copper and polycarbonate solar collectors, and probably use a simple drainback system that could also include the hot water heater.

My question for those of you with solar thermal experience: How effective would it be? (assuming proper angling of panels and midwest weather/climate...) Would I be able to heat one room adequately when it's sunny with one 4x8' panel, or my whole house if I covered my roof?
I see that many people have used small-ish panels to cover 90+% of their hot water needs.... is there enough extra to space heat....really?

Daox · 10-19-09, 08:10 AM

I have hydronic floor heating in the sunroom in my house. It is wonderful. However, right now it is just running off of the hot water heater. Going forward with my home projects, I'll be using hydronic heat as I would like to go with a solar heating system as well.

From what I have read, 50% of your heating from solar isn't too hard to do. 70% is more difficult, and 90% is really quite high. You'll need a fair amount of panels and also a very large amount of thermal storage to maintain heat during cloudy days/weeks.

In order to size your system, you'll want to estimate the heat loss of the house to see how much energy is required to heat it. I think a very easy way of doing this is looking at previous bills. X therms of gas = X kWh (you can throw in the efficiency loss of your furnace too). You'll compare that to a solar map that shows you how many kWh of heat you can get from the sun per square meter. It looks like you can get 4-5 kWh. From that, you can calculate the square footage of collector you'll need to heat your home. I'm not sure exactly what kind of efficiency Gary has been getting out of his panels either, but you'll have to include that. You'll also have to take into consideration that you can get sun for X hrs each day, and that you'll also have to harvest more heat for cloudy days, etc.

If you don't think that your house is as well insulated as it could be, I'd really start there (and I am actually). Insulation is cheap compared to solar stuff.

Daox · 10-19-09, 08:34 AM

I just decided to do the calculation for my energy usage for the last month as an example (for me as much as for you).

I used 192 therms of natural gas last January. This is by far the worst month I had. Anyway, 192 therms over 35 days is 5.5 therms per day. My furnace efficiency is around 90%, so 5.5 *.9 = 4.9 therms is roughly my daily usage. Lets convert that to kWh and we get 143.6 kWh.

Now, in my (and your) part of the country, we can harvest 4-5 kWh per square meter per day. So, lets take 143.6 and divide by 4.5. That gives us 31.9 square meters of panel. A square meter is 10.8 square feet, so we need 345 square feet of collector roughly. I still haven't compensated for cloudy days or efficiency loss through the collector. For reference, Gary's solar shed is 240 square feet.

The good news for me is that my house is horribly insulated, so I can likely reduce that 192 therms drastically. Hopefully yours is already lower.

gascort · 10-19-09, 09:52 PM

Thanks, Daox. lol - regarding the horribly insulated.... your tatooine basement is not much better than my house - we have no insulation in many areas of our home and where there IS insulation, it is done wrong - except for the stuff I've re-done.
I'm getting there... but slowly. Plus, it's not as fun!
I 'm actually going to have some students at school work with me to design and install a drainback system run from PV power. Will be a good learning and teaching tool for them and myself.... We already have an old solar thermal panel and some PV panels.
Thanks for the solar map info.... will do some thinkin'...

Daox · 10-20-09, 07:09 AM

Very cool idea. Keep us updated on what they come up with.

cloves · 03-11-10, 07:51 PM

Yeah def update this thread. I am also curious about this. thanks!

10-18-09, 08:48 PM	#1
gascort Helper EcoRenovator Join Date: Feb 2009 Location: Saint Louis, MO Posts: 59 Thanks: 0 Thanked 0 Times in 0 Posts	Hydronic radiant heating? Anyone made a DIY hydronic radiant heating system? Maybe one that uses solar energy? Simply Radiant \| Extreme How To, DIY - Do it Yourself, Home Improvement, Home Decorating I was thinking it could be added to my house; we have exposed joists in the basement ceiling, could use PEX tubing run back and forth under the floor there; would heat the basement below and the floor above. I want to ecorenovate our roof using builditsolar - style copper and polycarbonate solar collectors, and probably use a simple drainback system that could also include the hot water heater. My question for those of you with solar thermal experience: How effective would it be? (assuming proper angling of panels and midwest weather/climate...) Would I be able to heat one room adequately when it's sunny with one 4x8' panel, or my whole house if I covered my roof? I see that many people have used small-ish panels to cover 90+% of their hot water needs.... is there enough extra to space heat....really?

10-19-09, 08:10 AM	#2
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I have hydronic floor heating in the sunroom in my house. It is wonderful. However, right now it is just running off of the hot water heater. Going forward with my home projects, I'll be using hydronic heat as I would like to go with a solar heating system as well. From what I have read, 50% of your heating from solar isn't too hard to do. 70% is more difficult, and 90% is really quite high. You'll need a fair amount of panels and also a very large amount of thermal storage to maintain heat during cloudy days/weeks. In order to size your system, you'll want to estimate the heat loss of the house to see how much energy is required to heat it. I think a very easy way of doing this is looking at previous bills. X therms of gas = X kWh (you can throw in the efficiency loss of your furnace too). You'll compare that to a solar map that shows you how many kWh of heat you can get from the sun per square meter. It looks like you can get 4-5 kWh. From that, you can calculate the square footage of collector you'll need to heat your home. I'm not sure exactly what kind of efficiency Gary has been getting out of his panels either, but you'll have to include that. You'll also have to take into consideration that you can get sun for X hrs each day, and that you'll also have to harvest more heat for cloudy days, etc. If you don't think that your house is as well insulated as it could be, I'd really start there (and I am actually). Insulation is cheap compared to solar stuff. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-19-09, 08:34 AM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I just decided to do the calculation for my energy usage for the last month as an example (for me as much as for you). I used 192 therms of natural gas last January. This is by far the worst month I had. Anyway, 192 therms over 35 days is 5.5 therms per day. My furnace efficiency is around 90%, so 5.5 .9 = 4.9 therms is roughly my daily usage. Lets convert that to kWh and we get 143.6 kWh. Now, in my (and your) part of the country, we can harvest 4-5 kWh per square meter per day. So, lets take 143.6 and divide by 4.5. That gives us 31.9 square meters of panel. A square meter is 10.8 square feet, so we need 345 square feet of collector roughly. I still haven't compensated for cloudy days or efficiency loss through the collector. For reference, Gary's solar shed is 240 square feet. The good news for me is that my house is horribly insulated, so I can likely reduce that 192 therms drastically. Hopefully yours is already lower. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.* To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-20-09, 07:09 AM	#5
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Very cool idea. Keep us updated on what they come up with. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-19-09, 09:52 PM	#4
gascort Helper EcoRenovator Join Date: Feb 2009 Location: Saint Louis, MO Posts: 59 Thanks: 0 Thanked 0 Times in 0 Posts	Thanks, Daox. lol - regarding the horribly insulated.... your tatooine basement is not much better than my house - we have no insulation in many areas of our home and where there IS insulation, it is done wrong - except for the stuff I've re-done. I'm getting there... but slowly. Plus, it's not as fun! I 'm actually going to have some students at school work with me to design and install a drainback system run from PV power. Will be a good learning and teaching tool for them and myself.... We already have an old solar thermal panel and some PV panels. Thanks for the solar map info.... will do some thinkin'...

03-11-10, 07:51 PM	#6
cloves Lurking Renovator Join Date: Feb 2010 Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	Yeah def update this thread. I am also curious about this. thanks!