slab hydronic heat set up with possible solar and wood stove

scuba

Hello all, big newbie to all this but have been ready this and many other sites (anything Google points me to with any relevance).

I am setting up my shop 30x32x12 steel pole building, 6" floor, R20+ wall, r30+ceiling, P2000 floor insulation #10 mesh, 1/2" O2 barrier PEX w/4 equal length runs 12" spacing. I have vapor barrier on walls, floor and ceiling. according to online calculator, I have approximately 25,000 btu heat loss(using 10% margin of error and rounding up)

For equipment I have the pex and manifold (with temp/flow gauges, vents) only, I am very budget minded both with build and operation costs. I have intentions of adding a couple of DIY solar panels to offset fuel costs as well as a wood stove. I am looking for recommendations on both plans, and parts (heaters, controllers, what to do/ not do, etc)

My initial idea was to use a ground loop or geothermal circulation to both heat in winter and cool in summer the slab to approximately 50 degrees with just a circulation pump, but could find no information as to square footage requirements. My guestamations (lol) led me to believe this was not feasible, so this also led me to other alternatives.

I restore cars as a hobby and need to minimize temperature fluctuation. My idea(s) is to use a closed loop system with DIY solar panels (which will offset fuel price) keep the shop at the same 50-55 degrees and use the wood stove as needed when using the shop to reach approximately 70 degrees, also thoughts of designing a wood stove heat exchanger to help with efficiency.

any thoughts for plans on my Ideas would be greatly appreciated. I am geared towards a simple electric/propane water heater as it will also help store solar heat.

As I said I am very green and trying to learn, I enjoy learning and building/creating new things but do not wish to reinvent the wheel nor open a plumping and heating shop

Thank you for reading this and in advance for any and all help

SWEI

scuba said:

6" floor, R20+ wall, r30+ceiling, P2000 floor insulation

Don't waste your money on P2000 under the floor. It's all about conduction (R-value) there, so the radiant barrier adds nothing. Where are you located, and what are your winter temps like? Has anyone done a heat loss calc? Do you have NG available?

scuba

north central ohio. online heat loss shows approximate 25000. winter temps are teens/20s (F) typically but can vary lower than that. no natural gas unfortunately

SWEI

Was that heat loss done using R-4.11 for the walls? What is your winter design temp?

You want a minimum of two inches of XPS or EPS foam under that slab. Three would be better.

hot_rod

Here is some good info on design and piping

http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_6_0.pdf

scuba

swei, I only used R20 for walls as they will roughly 8" of blown in fiberglass plus interior sheeting. building is also house wrapped.

Hot rod, thanks looks like a great site with a lot of stuff for me to chew on

scuba

also I used 20 degrees for average temp as it is a shop and night hour temps were SORT OF irrelevant. My main usage time of the shop will be afternoon/early evening

hot_rod

My shop is about 1200 sq ft. I have about 155 square feet of thermal collector, wood boiler and LP back up.

Once you have an accurate load number, run a solar simulation to see what portion of the load you can cover, with various array sizes..

Those air to air solar collectors work well on shops also, simple to construct.

Brewbeer

Has the floor been poured yet or is there still time to put insulation beneath the concrete?

scuba

I have 5/8 P2000,6 mil plastic, and 6" #10 mesh placed with concrete coming on June 11th. Pex will be placed tonight after work. P2000 was the recommendation from (not sold by) our local radiant heat retailer. they also configured the design/layout recommendation for the PEX tubing runs??

SWEI

scuba said:

P2000 was the recommendation from (not sold by) our local radiant heat retailer

P-2000 has an R-value of 4.1 per inch, per their own website. R-2.5 is nowhere near enough insulation under a heated slab. You want a minimum of R-10 (two inches of EPS or XPS foam, with three or four inches being better.)

scuba

I was advised to this product (actually the 3/8 version) and was skeptical, a friend highly recommended it, still skeptical after mixed online reviews but found this (below) along with a few other (and personal) testimonies and am convinced enough to use it


FIELD STUDY 1” P2000 INSULATION SYSTEM VS R 20, 6”FIBREGLASS Miniature buildings with identical interior dimensions (23” wide X 34” long X 27” high). Both buildings are heated with a 100 watt light bulb and are constructed to National Building Code standards. The fiberglass building is 2X6 construction. The P2000 building is 2X4 construction. 2 X6 Fibreglass Building Six inch R 20 fibreglass insulation complete with a 6 mil poly vapour barrier was installed on the inside of the walls and the ceiling. Note# In order to observe the performance of the insulation a (TEMPORARY) exterior layer of poly was installed. The poly held the insulation in place and protected the fibreglass insulation from the weather. There was no exterior OSB installed at this time. The building was set on one inch R-5 extruded polystyrene insulation. 2 X4 P 2000 Building1” P 2000 was installed with no vapor barriers. There was no exterior OSB installed. The building was set on a one inch piece of P2000. Observations Nov 10 / 2006 Outside temperature -3 C.Two miniature buildings were constructed indoors. Buildings were moved outdoors. The small 12” X 12” windows in both buildings were facing the sun (south). The heat was activated (100 watt light bulb) in both buildings. In 25 minutes the P 2000 building reached 25C.Fibreglass building required 2 hours & 44 minutes (six times longer) to achieve the same interior temperature as the P 2000 building. Observations Nov 14 / 2006 Outside temperature + 4C to -6C Day windy 25 KPH gusting. Night no measurable wind.Fibreglass Building: After three days condensation was noticeable on the inside of the exterior vapour barrier. When windy the fibreglass building’s temperature was 10C colder than the P 2000 building. Average night temperature (no wind) in the fiberglass building was 3 to 5C warmer than the P 2000 building. P 2000 Building: No condensation formed. Wind had little to no effect on the P 2000 building. Daytime temperature was 10C warmer than the fiberglass building. Observations Nov 30 / 2006 Outside temperature -14C / 10 to 15 KPH WindsFibreglass Building: Exterior vapour barrier was removed. Fibreglass insulation was frozen to the vapour barrier. No other moisture was apparent in the fibreglass insulation. Building was left without outside vapour barrier for one day. Temperature dropped (10C) without exterior vapour barrier.P 2000 Building: The P 2000 building was 10C warmer than the fibreglass building after the exterior barrier was removed from the fiberglass building. Observations Dec 1 / 2006 Installed 7/16 OSB on both buildings. No temperatures recorded. Observations Both Buildings Dec 6 / 2006 4:45 PM Outside temperature -17C Light WindInterior Temp. P 2000 Building 22CInterior Temp. Fiberglass Building 19C9:30 PM Outside temperature -22C Light Wind Interior Temp. P 2000 Building 20C Interior Temp. Fiberglass Building 17CObservations Dec 7 / 2006 6:45 A.M Outside temperature -25 Wind Gusting to 50 KMH Fiberglass Building: Heat source was shut off for approximately two hours. One section of the OSB was removed. Condensation in the fiberglass insulation was apparent. OSB was re-installed. When the heat source was re-activated the interior temperature was -5C.The fiberglass building required over 9 hours to achieve an interior temperature of 15C. P 2000 Building: Heat source was shut off for approximately two hours. Conventional thinking suggests radiant barriers do not perform (reflect radiant heat) when covered by a conductive surface such as drywall. Removed the P 2000 building from platform and installed ½” drywall directly over the P 2000 on the walls and ceiling. i.e.: There was no air space between the P 2000 and drywall. Re-installed the P 2000 building on the platform. When the heat source was re-activated, the interior temperature was -25C.The P 2000 building recovered (40 C) in approximately one third the time it took the fiberglass building to recover (10C). Observations Both Buildings Dec 8 / 06 7:10 AM Outside temperature -9C Light Wind Interior Temp. P 2000 Building 19C Interior Temp. Fiberglass Building 17C 7:00 PM Outside temperature -11C No Wind Interior Temp. P 2000 Building 25C Interior Temp. Fiberglass Building 25CBoth Buildings March 2 / 07 Outside temperature -10 Light Wind and SunnyThe heat source was turned off in both buildings. The sun was shining directly on both buildings. The P 2000 building maintained an interior temperature of 15C while the fiberglass building maintained an interior temperature of 6C.Overall ObservationsThe buildings were monitored sporadically for the balance of the winter. Relative to the outside temperature the overall trend was consistent with the above observations. Whenever the heat source was turned off and then re-activated the P 2000 building achieved the desired interior temperature 5-10 times faster than the fiberglass building. With or without an exterior barrier or sheathing the fiberglass building was adversely affected by wind. The interior temperature of the P2000 building was virtually unaffected by wind. The fibreglass building developed condensation in the wall and ceiling cavity while the P 2000 building showed no signs of condensation anywhere. In sunny moderate winter temperatures (-10C to 0C ) the P 2000 building was able to maintain an average interior temperature of 10 to 15C while the fiberglass building averaged an interior temperature of only 3C to 6C. When the outside temperature ranged between -8C to +5C with no wind and no sun the interior temperature the fiberglass building was 2 to 3C warmer than the P 2000 building. Overall the P 2000 building maintained a significantly warmer interior temperature than the fibreglass building. Significantly less time was required to install the P2000 Insulation system than the fiberglass insulation, vapour barrier, vapour box, stapling and acoustic sealing.Angela ProntiManagerFireProof Paints & Products1764 Empire Blvd., Suite 9 Webster, New York 14580Phone: 585-787-9302 x 18Fax: 585-267-5218 - See more at: http://www.metalroofing.com/v2/forums/index.cfm?action=mboard.members.viewmessages&ForumTopicID=5230&ForumCategoryID=38#sthash.WmHrqnkE.dpuf

scuba

I'm not trying to argue beliefs and apologize if I seem ungrateful because I am surely not, I am looking more for info and recommendations for combi system equipment/components pumps, boilers, controllers, etc,. trying to figure out what I can get by with as funding is concern for this project. I intend to construct thermal collectors based off of proven units on the Build It Solar site . I also have an abundant wood collection and am becoming energy/waste conscientious. I am very mechanical and skilled, Im just not yet knowledged in these areas.

SWEI

Walls and roofs are exposed to air on both sides, so radiant energy does affect their performance. The best way of quantifying that effect is the subject of ongoing (rather heated) discussions in the industry.

Slab insulation is in direct physical contact with the earth and the slab. A radiant barrier offers no benefit under those conditions.

Find me a study that compares P-2000 to EPS or XPS foam under a slab.

njtommy

Laying on a Cold concrete floor is no fun ( I know i will get hell for this comment) but have you looked into Ductless split for heating and cooling the garage? They will heat down to -10F out side and aren't too expensive to install or run.

hot_rod

SWEI said:

Walls and roofs are exposed to air on both sides, so radiant energy does affect their performance. The best way of quantifying that effect is the subject of ongoing (rather heated) discussions in the industry.

Slab insulation is in direct physical contact with the earth and the slab. A radiant barrier offers no benefit under those conditions.

Find me a study that compares P-2000 to EPS or XPS foam under a slab.

Healthyheating.com, hosted by Robert Bean has some solid data on under slab insulation.
http://www.healthyheating.com/Radiant_heating_designs/insulating-underslabs.htm#.V1iXsVc3clI