Hydronic Heat in Woodworking Shop

Phil Gaudio

I am planning on adding a zone to my oil fired hydronic system to provide heat to a woodworking shop. The pipes will pass from the house through an unheated garage space to the shop, and I suspect there may be times when this zone will be shut down, i.e., freezing is an issue. I am thinking I should use a plate type heat exchanger and use some sort of antifreeze in an isolated loop for this zone. In addition, I will have to insulate pipes in unheated spaces. Any thoughts on how to accomplish this?

hot_rod

Sound thinking

You might consider an indirect tank as both a HX and buffer tank if this is a small load zone on a large boiler. Glycol just the coil and loop to the shop. Run the tank at boiler temperature and draw your shop loop from the coils with a 3 way thermostatic to modulate the temperature, would be one simple way.

Remember the "B" side of the HX or tank will need an expansion tank and relief valve.

I'd go with 1" fiberglass pipe insulation, possibly foam if you can UV protect it, through the un-heated spaces.

hot rod

Phil Gaudio

Thanks for the advice

Thanks for the info. Now to decide whether to use baseboard (cheap and effective) or radiant slab (sig. more expensive and maybe more effective).

Dan Peel

emitter choices

In a wood working shop be conscious of dust and having to keep specific areas clear. Panel rads may well be a better choice than either radiant or baseboard. If the area is to be heated for days or weeks at a time radiant is great - for only sporatic heating select quicker response emitters. Dan

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

kevin

i have done...

a coulpe slabs in work areas...very nice. Another option would be to find a few old cast iron rads(hot water) to use. They are durable and often people are just tossing them out.kpc

Phil Gaudio

Why a 3 way thermostatic valve?

One question: why use a 3 way thermostatic valve to modulate temp? Could you instead adjust the output temp of the water heater to some fixed value? Then, instead of modulating the temp of the loop, you just control whether the loop is on or off, just like baseboard heat.
Thanks again for your help.

mike celiano

Thoughts

Phil,
I would recommend a HW fan forced unit heater.This would be controlled as follows.As the space thermostat calls for heat-it will energize a local zone valve whose endswitch will start the boiler. Once HW is available, an aquastat, mounted on the supply or inlet line of the heater will then enable the fan to start. When finished or unoccupied mode the space will maintain the lower setting.
The space thermostat could have a remote sensor to average the adjacent area as well for freeze protection. As long as you maintain flow,a freeze condition won't occur.

Tom Meyer

Response time

Just something to remember when considering options:

A slab system has a slow response time. You're going to be pouring alot of BTUs into the area to get it started up. It's one of the advantages of the slab system, but depending upon the application, can also be one of its handicaps.

The baseboard system is a dust collector. The dust acts as insulation and cuts down on system effectiveness.

Rad panels seem to make the most sense. Faster response. The drawback there is most workshops have things hung all over the walls.

Overall, stick with a low mass, faster response system, if that's what you have in mind. Also take into consideration the restrictions the design places on hanging things, and above all, remember woodshops are lovely places for fires.

Senior Designer/Trainer
Precision Hydronics Corporation
www.precisionhydronics.com

Mike T., Swampeast MO

2nd for iron rads

That is unless you need the space heated continually--then in-slab radiant would be HIGHLY preferable to baseboard.

My woodshop is currently in what will be my library and family room. The inevitable accidents that might harm or even destroy a panel or baseboard won't bother an iron radiator in the least.

Since a shop has to be fairly spacious, the physical size of rads isn't too much of an issue. They also make a nice warmer for a cold gallon of glue, etc.

For relatively quick response when needed yet gentle temperature while maintaining would suggest that the rads be quite oversized (design load at 140° or so) and the use of TRVs. The TRVs don't seem to mind the dust but I do brush/blow them off occasionally.

With their hefty radiation and gentle convection I find that I can enamel is a space filled with SETTLED sawdust without fear of contamination--impossible with a forced air system. Have also found that my natural finish work turns out MUCH nicer in a space without much convection.

With a little patience and persistence you can find plainer, non-sizeable iron rads in most locations for little cost--often even "free for the hauling." If at all possible don't forget to get BOTH HALVES of the valves/unions to save the expense of buying new.

jim f

if using a fan coil unit, i would suggest not using an aquastat, instead use a time delay turning the fan on. sequence of operation would be as the t-stat calls for heat-circulator comes on, after preset time on the delay is met , sends 24volts to fan relay coil on unit closing 120 volt contacts to power fan. when t-stat is satisfied the fan and circulator turns off.

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

hot_rod

blower type

of heaters are not my favorite for wood shops. Too much airborn dust. Hard on the unit itself, and the occupants to have saw dust and sanding dust stirring all the time

I, too, would look at radiant floors, ceilings, or walls. Or even a combination of these. Radiant ceilings in a shop with a lot of benches or floor mounted equipment, might be a nice fit. It also allows you to bolt down equipment to the slab, without worry.

Second best would be panel or standing radiators, in my opinion.

Sealed combustion boilers are also a must or locate them in a seperate sealed room.

hot rod