boiler vrs water heater?/Jubil

Jubil

Love the wall, hope you guys can help.

Info: Currently building a garage, infloor tubing installed in slab. Now would like to determine: 1.heat loss of structure and 2.) if a propane water heater could be used as heat source vrs boiler? 3.: Heat requirements are to make it warm to break chill to work on motorcycles, wood shop and weld area, no living quarters.

Facts: Shop is 44 ft x 50 ft. 2x6 exterior-insulated. 12 ft interior walls-12inch attic blown in. covers the shop. There are three garage doors- 2@ 9ft x 9ft and 1 @ 10ft x 10ft. The shop is divided into 3 sections, half the shop is open the other half is split into two. There are 7 exterior windows at 3ft x 5 ft- and 3 metal access doors/ 3ft doors.

Tubing installed: 8 loops of 1/2" Oxygen barrier tubing. Each loop is 250 ft. (total length for each) I spaced the lines 9 inches appart on outer edge and 12inches apart in main floor. I have 2" of blueboard seperating the concrete slab from the footing and foundation walls and 1inch of blue board under the slab. We tried to keep the tubing middle of the pour as the concrete was being poured.

Location: I am located in Washington State (Eastern side) Richland, Wa. The climate is mild through the winters, snow doesn't stay long but it does get well into freezing/minus temperatures on hard winters.

whewwww... still with me? O.k., here comes the questions: I will be using Propane as energy source. I would like to warm the building up to make it comefertable, doesn't have to be liveable, I know lag time etc regarding warming of floor etc... Don't be shocked but I am trying to keep costs down.... could a gas water heater/40 gal gas water heater and could an auto dampner/flue vent be installed or possibly point of use unit or should I get the a-typical cast iron boiler? What might work in this situation. I like the boiler as I could run some 180 degree temp water too some forced air units to help dump heat into the room... but not sure of economics of that.. or will the water heater give me enough heat vrs dollars to warm up the building?

Your input is greatly appreciated Hyrdronic wizards!

The e-mail above is temp so don't use I wanted to get this posted to get it started. I can reply back with a new e-mail in a day or two as new account being set up.

Thanks in advance, Jubal

Mark Hunt

Hello Jubil!!

I think you may be beyond the realm of a standard gas water heater as far as BTU's go.

Just rough numbers here but, 2200 square feet with say a 25 btu per square foot heat loss puts you at 55,000 required output.

I think that I would recommend a boiler for this application.

You could throw a plate heat exchanger on for domestic hot water if you are going to have a slop sink or bathroom.

Burnham makes some excellent products that may fit the project and the budget.

Post some pics if you can! Gotta' get out that way some time to do some fishing. Oh......and you can post pics of the garage too if you want!!!

Hope this helps!!

Mark H

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Jubil_2

How about on demand

Thanks for the reply, so now it comes down too cast iron or wall mount/condensing unit. (Sorry cant remember mfg of wall mount unit but built for in-floor and supplyer fax'n me info.)

Wouldn't the on demand wall mount unit make more sense as this is luxery heat for shop (no living space) no potable water too heat and if it breaks I don't care how long it takes to get a part to fix.

A cast-iron would have a higher heat loss do to heating/cooling of cast iron and larger reserve of water in unit to heat up but it would offer the higher temp that I could add hydronic fan coil etc. to dump lots of heat in a hurry to warm air in shop.

The wall mount condensing boiler is running about 1/2 the price of the cast iron which makes it appealing and probably more efficient?

Also, I am worried of short cycling using cast iron boiler, the cast iron boiler is 75,000 btu, Is there a possible chance of short cycling with this system or is there a storage tank that should be used along with this as a capaciter (storage of heat).

FYI: I am familiar with condensing /non-condensing boilers and uses, water temp, mixing valves, pumps etc..
but unsure of best choices, so thus I turn to those who know. Hydronics isn't very big in this area as more desert area so no one to visit with locally. I am calling up to Spokane to gather info and find this website very helpful.

What say you, gods of Hydronic's?

Floyd

I would...

seriously consider the hot water heater.
With LP you should be able to find say a 50 gal.
unit that will get up towards 50,000 BTU which will
get you close enough for the majority of the year.
But one other thought, how bout a high eff. type direct vent
job like a Polaris, being that you are using LP.

Just some thoughts....

Floyd

Paul_6

Polaris

I installed a polaris as the primary boiler in a good sized house about two years ago. it's what the home owner wanted, he had hot water from an electric I think. so the polaris only did the radiant floor. that heater had to be 50 to75 mbh and it worked o.k. considering the mile long loops the guy had installed himself.