Which heating source for in floor heat?

[Fastback]

Here, this is the very first video I found when I did a casual search. This shows how they can gather heat even in snow. What would it do on a 30º-40º day? I would think it would really contribute to the heating system then!

I would think one could improve on this setup because I dont like the panel in this video, the tank on top of the tubes is not the optimum setup.

My next system will be a hybrid. Of course, internet "experts" said my current system would not do really well either...go figure.

 

[anthony666]

wow fastback .. who pissed in your cornflakes ??

i do know lots about solar .. a big chunk of my business is solar dhw .. i have factory training from veissmann & enerworks on their solar water heating systems .. what exactly do you have ???

the biggest problem with solar is that heat is not cumulative .. 50 degree water plus 60 degree water does not equal 110 degree water .. as the azimuth of the sun changes during the winter the amount of the sun's radiation per square foot decreases and the length of the day shortens meaning you get less and less energy from the sun .. that's why the portion of the planet that is under those effects experiences winter

even with evacuated tubes, which are not new technology, present solar technology is not sufficient to run a heating system cost effectively .. if your return temps drops to the point where you can add heat from solar gain in january and you are comfortable, good for you .. i'm very happy for you

i'm not trolling anything here man .. if you think i'm some kind of **** here on some kind of agenda please pm me, or call me out on it .. im just trying to stop people chasing fool's gold

 

[anthony666]

This shows how they can gather heat even in snow. What would it do on a 30º-40º day?

i have solar panel hooked up to my 500 gallon stock tank for my horses to drink it just runs by a simple submersible pump and keeps it above freezing .. im not saying you cant make heat at all in the winter via a solar panel .. i'm saying you cannot economically make enough heat to drive a slab to a comfortable level and the part you seem unable to grasp is HEAT IS NOT CUMULATIVE .. you must inject water above the lowest temp in your system (return temp) or you will have a negative effect

 

[Highbeam]

im not saying you cant make heat at all in the winter via a solar panel .. i'm saying you cannot economically make enough heat to drive a slab to a comfortable level

As an outsider to the ******* match I see this as the issue. You each have different performance goals and I think you would both agree that 100% solar will not do the job all year.

 

[anthony666]

woah woah .. i'm not in any ******* match

 

[anthony666]

i really don't understand the hostility at all .. i'm not billing for this info .. is it because i'm not affirming what you wanna hear ?? i do this **** for a living so yes i have some insight into this stuff that might be useful

i learn other stuff from this forum, i wanna pay back, it's not rocket science

if i'm not welcome please tell me, i got other **** i could be doing with my time

 

[walrus]

As an outsider to the ******* match I see this as the issue. You each have different performance goals and I think you would both agree that 100% solar will not do the job all year.

I'm in Maine, its been one ***** of a winter. We've had more below 0f nights here then any winter I can remember and my memeory goes back a ways. My solar panels are homemade, I'm not anywhere near the efficiency of a factory built copper collector and my shop has never dropped below 40 using just solar for heat. Now the caveat is my shop was built for solar, R54 ceiling, R33 walls, foam, cellulose, fiberglass, tight and I mean tight building, one 10 by 10 insulated door, couple windows on south and west sides and a man door. Solar works but it isn't keeping my shop in tee shirt temps. Right now its 50 out there, wasn't sunny yesterday but the collector ran as the suns packs a punch right now, getting ready for a rather large snow/rain event so it isn't running today, nor will it run tomorrow. By this weekend when its sunny and 40s again my shop will be back in the 50s. I have a woodstove for when I need it tee shirt temps. I'd love to see how the system would work with 4 or 5, 3 by 8 ft factory built flat plate collectors.
As far as DHW is concerned I have 2, 3 by 8ft copper flat plates on my roof, its easy to get 160f water at this time of year, all you need is a sunny day. Not sure what snow has to do with anything but there is plenty outside

 

[anthony666]

ironically i did a service call today .. complaint; pump running, pipes 'cold' .. system log showed it had been running in freeze protection mode for 68 days .. in layman's that is when the solar side pump runs and the system is allowed to pick up ambient heat from INSIDE THE HOUSE to stop the system from freezing and bursting the piping .. it is in effect operating in reverse .. please tell me again about your plan to heat your structure via solar power & what an 'internet expert' i am

 

[rburke65]

Hmmm....... I don't see a response from anyone anthony666....

 

[Legwound]

I'll drop in here as this looks like as good a thread as any for my question, I see lively discussion which to me means lots of eyes and experience.

I'm planning a move to Nova Scotia within a year or so and for see a large shop with radiant in floor heat. I'm tossing around the idea of a wood boiler as wood will be available.

I also recently went to a home show and got some reasonable pricing on trenched geothermal. If I couple that with provincial efficiency rebates it may be doable and more attractive than a wood boiler.

Is it possible to configure a radiant system that circulates convectively without circulation pumps?

I'm thinking of looking for a south facing sloped property and having my heat input lower than the shop.

I'm trying to imagine a system that has the lowest power demands possible. I imagine I'll need power for a heat pump if I go geothermal but eliminating circ pumps would be nice.

I'm in Ontario and had a several day power outage over the winter and would like to be able to go to an off grid heating system in cases of emergency. I'm thinking maybe a small Photo voltaic panel and battery bank for the heat pump and convection for circulation.

Am I out to lunch?

 

[volleyball]

Where the heck is the OP? Been over a week and not one response.
I'd like to know the usage pattern desired before I say go one way or another.
Doesn't matter if we just want to take the chill off, use it just on weekends or full time, it is what the OP wants and we have no clue.
I think most suggestions presented will work to a point. Even knowing a budget leads us towards a particular solution. A large old inefficient boiler might be the cheapest overall solution given the situation.

 

[Denwood]

My first post, but I see a lot of questions here on heat, but very little on sustainable behavior. I'm in a midst of a garage reno, so will post a bit about that (8ft to 10ft ceiling + MaxJax lift all in for $3000) We have long winters here, with temps dipping below -35C in the winter. Just over a year ago we finished a 2 level, 10 000 sq/ft warehouse renovation including insulated the existing slab followed by 4" over-pour with 4500 sq/ft radiant, and five air handler units for AC/HRV. We used a furred air space wall technique (building was gutted back to studs), spray foaming at the apron, and cellulose to r80 in the attic space.

The renovation was intended to be phase one in getting to a net-zero footprint for Cinevate. Last winter was the coldest recorded in the last 35 years with 61 days below -20C. The building is heated with a single triangle tube NG wall mounted unit, which is a "backup" solution for yet to be installed evacuated tube system. There's little incentive actually to complete the project as the building is extremely efficient. During last winter, our largest bill for gas usage over 1 month was ~$300. That's 10 000 sq/ft heated to 20C during business hours and set back evenings/weekends. Our loading bay has a 14ft overhead door, nothing fancy for insulation. Our roof was modeled for PV as well as evacuated tube arrays. Fully sensor driven lighting as well as solar modeled window placement and clerestory/passive ventilation features add to a very pleasant workspace.

Start with an efficient envelope...and evacuated tube solar can be 100% of your heat with the correct design. There are several examples locally of evacuated tube heated garages.

This is a great example of good planning:
http://www.latitude51solar.ca/solar...-heating-homes-with-evacuated-tube-collectors

Cheers,
Dennis. (CEO, www.cinevate.com)

 

[Legwound]

That was a helpful article for me,as were the links to other articles within it. I especially liked the thermostatically controlled, finned tube system for excess heat dump described in one of the linked articles.

Looks like having a really big tank for heat storage will maximize the effectiveness of solar. Since I'm in the very early planning stages of a build I have the opportunity to do just that.

I toured a dome house with evacuated tubes on the roof and the guy said he had to dump heat at times and needed supplimental in winter. I think this will always be the case to some degree but he had 80 gallons of storage and that was it. From what i gather he is suffering from not enough thermal storage capacity to maximize solar heat capture. I'm keeping this in mind for my upcoming build.

I think 10,000 plus gallons of storage insulated and set under the floor of my building will allow me to run 2-4 banks of solar and get decent capture and storage with minimal supplimental heat. All that said with me not even having nailed down building size.... I plan on at least 40 x 60 foot, possibly double story on the Bruce Peninsula in Ontario (equivalent to Michigan I figure). So good insulation and a tight building are a given also.

I'm obviously just spitballing right now but getting a better feel for things.

I also need to nail down the best supplimental heat source. Electric seems easiest and cheapest for initial install but more expensive to run. Natural gas is not available, but propane is an option but buying a tank and suffering fluctuations in fuel prices less palatable. The building will have a woodshop so lots of scrap for a wood boiler.

More research required. Glad I found this forum.

 

[Legwound]

I'm curious if raising the temperature of water/glycol exiting the evacuated tubes before then sending to a large tank/heat storage unit has any merit.

I came accross this DIY solar concentrator which I'm speculating could further raise the temperature of the output of the evacuated tube heaters.

Funny thing is this guy I found online is in the very town I visited in my hunt for real estate. I'll be talking to him personally.

Anyway for the experienced folks here, am I out to lunch with this idea?

http://georgesworkshop.blogspot.ca/2012/08/diy-solar-parabolic-trough-20-intro.html

 

[ketas47]

I just wanted to do a summary of using a Navien 210A natural gas on demand water heater for my infloor heat. I installed it in 2012 and works awesome. Only maintenance I had to do is replace a water flow sensor ($15). Works better than ever expected! Would do it again! I have 2 prior posts of my system and set up ,on this same original post back in 2014. There’s also pics of my system. So if someone tells you that the Navien 210 on demand waterheater won’t work for in floor heat, I totally disagree and have the history to prove it.