Hot crawlspace space for radiant heating

[Cjrac]

I am working on a building in Nunavut(very cold minus 50F design). Due to permafrost the buildings are built up on stilts. There is an insulated crawl space under the entire building. The client does not want in slab heating. The crawl space is heated with finned tube convector heaters. I am thinking of adding more capacity to these heaters to keep the crawl space at around 85F which will radiate heat through the slab above and thus provide radiant floor heating. The building is one storey and has baseboard convector heaters on the exterior zones and duct mounted coils on the interior zones. My main reason for wanting to do this is to keep the building core warm during night set back hours when the air handling units are down (no reheat coil capacity). Any thoughts or concerns with this idea? Thanks.

 

[Drazen]

the more you heat crawl space, the more you will lose to the outside through roof.

in radiant heating you have low temperature which reduces convective heat transfer plus increased insulation to the outside.

this is just a chat, but of you have some calculation program, put in it, the same capacities, and you will see huge difference.

ahu is down, but i assume baseboard heaters are not down?! interior spaces will not cool much if they don't receive outdoor air.

 

[Compositepro]

"the more you heat crawl space, the more you will lose to the outside through roof." I don't understand how that works.

You will need to insulate between the ground and the crawlspace and the walls of the crawlspace. How will the humidity be controlled? This is normally done by ventilating with outside air, which you cannot do if you heat the crawlspace. High humidity can cause a lot of damage.

 

[chicopee]

It seems to me that heating the insulated crawl space is a waste of energy, It would be better to heat the occupied portions of the building at night to a minimum temperature which in your case could be around 50 dF.

 

[Drazen]

yes, i mistaken it for attic. the principle is the same, though, it is just increasing losses through crawl space walls that are possibly even less insulated than roof.

 

[GMcD]

Why would the core of the building get too cool during night setback? Aren't the internal zones equipped with room sensors or thermometers that will cycle on the air unit and reheats on a call for heating at that lower night setback temperature?

I agree that trying to heat the crawlspace to create a warm floor is a huge waste of energy and virtually uncontrollable.