Number of unit heaters?

[m2e]

Hi,

I have a warehouse-like room where I wanted to heat with unit heaters. The floor area is approximately 1200 sq.ft. and it's square shaped. The heat loss is about 120 MBH.

How many unit heaters would you use? A big one or several smaller ones?

Thanks.

 

[trashcanman]

(4) heaters, 30 MBH each, (1) at each corner blowing parallel with wall, forming a circular (squarish) pattern to blanket all walls. All would blow in either clockwise or counterclockwise (plan view).

 

[RossABQ]

In general I agree with TCM, however it really depends what is in the warehouse. Are there racks along the walls? Are they tall, or are there other obstructions? This may drive more units at lower capacity. If there are occupied areas (like in a distribution warehouse) you may want to put some of the heat on the people. Are these gas or electric?

 

[DrRTU]

Your space seems to have very thin walls and roof at 100Btu/ft2 or you did not do a heat loss calculation. We are in 5A climate and most new buildings are less than 30Btu/ft2 for typical warehousing. Depending on use and racking, the most economical use would be to install one (1) unit at 100,000 to 150,000 Btu/hr. I check the throw tables to make sure I get coverage at the far side. If you are short on throw or have a high roof, add a destrat fan (57” or 60”) to improve the turnover. Do not forget about outside air.

 

[jmaglott]

RE-VERBER-RAY's website has design tools for unit heaters:

http://www.reverberray.com/design/design.html

 

[willard3]

It also makes a difference whether you are in the Northern hemisphere or Southern hemisphere and which way the Coriolis effect works where you are.

Blow direction of the unit heaters should take advantage of the effect, ie, cw or ccw.

 

[m2e]

Thanks for all the advices. From the RE-VERBER-RAY's website, I can only find information regarding infrared heater, but not unit heater. Maybe it's hidden somewhere, do you have a direct link?

For North America, what should be the Coriolis effect direction? Should I position the unit heaters blowing cw, or ccw?

Thanks.

 

[jmaglott]

I'm sorry, the re-verber-ray is infra-red heaters only. i'll check it next time before i post.

 

[ChrisConley]

1200ft2? Definetly a little small for that kinda heatloss, especially without ventilation.

I'd take another look at the heat loss.

For that size of building, for warehouse storage I'd think 2 unit heaters on opposite corners would accomplish your goal.

 

[Zapster]

willard3,
I can only assume that you are having fun with the Coriolis effect comment. Very funny. The Coriolis effect will have no measurable effect on your building’s interior circulation pattern.

 

[willard3]

Zapster:

Flush your toilet and see whether or not it works.

The effect works the same with air as it does with water.

CCW in Northern hemisphere, CW in Southern hemisphere.

Coriolis force per unit mass = 2 (omega)V sin(theta)

where:

* omega is the angular velocity of the Earth (360 degrees, or 2pi radians per 24 hours)
* V is the velocity of the object relative to the earth
* theta is the latitude in degrees

The Coriolis force is zero on an object moving over the equator (theta = 0).

 

[mauricestoker]

Hire an ME.

 

[AbbyNormal]

choose reznor space heating handbook gives tips on unit heaters, radiant heaters

https://www.rezspec.com/index.php?pageid=000000000014&mod_files

[currpos]=000000000087

It has NG and propane orifice tables, and a basic industrial ventilation table in it if you have no where else to start

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[AbbyNormal]

truncated link, have to copy and paste the entire thing

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[m2e]

Thanks.

 

[blutfort]

This has to be the most thought that has ever been put into a unit heater project.
;-)