Ideas for heating a wharehouse

todd s

I have a customer with the a storage wharehouse. This is approx 120 x 120 x 30. This is used to store furniture and there are also wooden storage crates. There is nothing temperature sensitive in this space except a wet sprinkler system. He is presently heating with 4 hanging natural gas unit heaters. The problem with these are: 1. difficult to service 2. high heating bills 3. twice (at least) they were hit by a forklift requiring the utility company to come shut down their gas until repaired. 4. Aged enough to be replaced.
He has asked my opinion and I would like to use a hydronic based system. There's no way to install radiant floor at this point. Would walls be an option? I had thought of running a hydronic trunk line around the ceiling and have it feed modine style fancoils. If the units were hung with chains and connected with pex, they could better resist a bump by the forklift.
I advised the customer to consider first insulating this space then re-doing the heat. I will perform a heatloss on this, he's getting me a set of plans and info on what insulation exists already. At this point I'm just trying to come up with ideas.

joel_19

warehouse

I like that scenario. ihate hanging gas/oil unit heaters as they are a pain to service. service would be simpler/cheaper with a boiler on the ground.

todd s

control

What would you suggest to control this? At this point I have the ability to choose any approach I want. Maybe run outdoor temp with longer fan on cycles?

harvey

infrared heaters

Go to detroitradiant.com They have a full line of infared heaters. Even two stage. We install alot of them in owner occupied buildings

todd s

infared

I had thought of them. The problem is they stack these boxes so high that I would be nervous about a fire. There looks like less than 3ft from the top of the highest boxes and they're wooden. Possibly could do them over the doors though. Thanks for the idea.

Kevinj_2

heating

I would look at an air rotation unit or the Green heck warehouse heating unit with 100% outdoor air.

Paul Pollets

Consider...

Steel fin tube, which can be heated by HW or steam; Radiant floors would be too costly to install, but the least expensive to heat.

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todd s

thanks Paul

What brands can you recomend for the steel fin tube? I would love to do radiant here but I was 20years too late for the concrete pour.

hr

Does it really need heat?

maybe just freeze protect the sprink system if you are just storing boxes and furniture.

I think just about all the codes require metal frames around fired unit heaters, by the way. Around here the drawings need to show that and be stamped by an engineer.

It's the first thing the inspectors look for, the spec and installation of the protective cages. A big liability issue, as you can imagine, especially in a warehouse full of cardboard!

hot rod

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todd s

yes it does need to be heated

The customer does want it warm enough to work in. They store furniture for short term while people are moving and long term in the boxes. If your box is buried 20deep you have to pay to have it brought out. About a third of the space is wood crates. The remainder is shelving(like in a big box store) and aisles. There are 3-4 workers moving things around all day and he does want it decent for them. I discussed only designing it for 50° at 0° outdoors. This is upstate NY, so it will be needed. A forced air system may be all thats needed but he asked what I'd do and I prefer boilers.

If this where to be a steel fin convection system, would it be more economical than forced air?

hr

I'm not sure where

you could locate the fin tube to assure good air flow. I'd agree unit heaters hydronic or gas fired or the radiant tube heaters would be best. As you mentioned the ceiling is unemcumbered so use this for the heat source.

Personally getting a comfortable working condition with a concrete slab being heated from the top with forced air just doesn't happen. The slab will be uncomfortably cold to work on,especially at 50° design. But since you don't have a choice.

We just wrapped up a woodworking shop with hydronic air handlers hung below the ceiling.

They actually came out cheaper than a suspended hydronic unit heater, are much quiter (squirrel cage as opposed to propeller fans), gave us a filter rack, allowed for some ducting, 4 speed motors to fine tune output,and has the ability to add an AC coil.

Used a wood fired, pressurized boiler, located outside the shop in an enclosed shed, for the heat source.

This was the insurance company requirement to have the wood fired equipment outside the building. We did find a wood boiler manufacture that has UL and ASME H stamped equipment, although not a high eficiency gasification unit.

We ran insulated copper (PAP would be an option also) to the airhandlers and made the final connection with 1" Onix rubber to allow movement and flexability should the units get bonked. They can swing and move up and down on a unistrut rack suspended by all thread, if needed.

hot rod

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harvey

low intensity

infrared heaters. They have to have an aisle for the lift trucks. You hang the tube heaters in the aisle or the loading areas. When you go to a wet heat site the only answer you'll get is wet heat.

todd s

infared heaters

This may end up as the way to go here. I just thought that I would see what kind of ideas other people came up with. I prefer hydronics, but the overhead radiant may be the best way to go here.

todd s

Just out of curiosity

How thick would the slab have to be if there are trucks/forklifts riding on top? Would this even be a consideration based on the fact that there's no slab insulation? I have been thinking about this and radiant seems like the best way possible to heat a space such as this. If there were a considerable fuel savings he may do the job.

hr

Depends on the weight

of the trucks and loaded lifts Generally 5 or 6" slabs are called for when heavy trucks are used. Rebar is often called for by the structural engineer, as is a tested and certified compaction of the subgrade. The slab is only as good as the ground below when loading is concerned.

On large spaces is is not uncommon to see just a 4 or 8 foot band of insulation around the perimeter. And of course edge insulation is always a must!

I'd watch you heat flux carefully with storage space. If 80% of the floor will be covered with boxes or furniture you will not get the output needed to meet the load, sometimes. Crunch the numbers! This is one of the main reasons why the overhead radiant tubes CoRaVac, etc are so common in storage facilities.

Maybe just consider radiant floors in the offices and shop spaces and overhead in the storage. Mix and match works fine. Hard to beat warm floors where folks sit at desks on concrete.

hot rod

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Rudy

cambridge

Look at cambridge direct fired equipment. I have appx 100+ units that I service in warehouse applications. The equipment can be indoor or outdoor configured, roof mounted or sidewall. Usually 1 pm visit in early fall is all that I preform umless the customer is using the equipment for ventilation in summer also. This brand of 100% ODA direct fired units have proven to be extremely reliable to me. The Contractor that I work for is the primary warranty dealer for the kentucky,indiana, ohio region, so I see many sloppy installations and this equipment is very forgiving. The Gordon-Roberts Co-Ray-Vac is another excellent system, just remember it is long wave uv and does not like to heat effectively above 15 feet although installations to 30 feet are not uncommon. Also with the co-ray-vac air stratification and proximity to sprinkler heads are also a concern.