Help- Costs for Water heat under concrete 1

[jackedup40]

I work in a steel mill and have a lot of return hot water from our mill. I would like to tap off from our header and funnel the hot water under the concrete to keep the concrete warm. We have all this hot water and we would like to utilize it. Anyone done anything like this? Looking for information on the process.

 

[ACtrafficengr]

Do a web search on radiant floor heating. It's becoming fairly common in residential and commercial applications.

 

[ERV]

Recently designed and built an airplane hanger and used radiant floor heating (hot water). The material for piping was AquaPex.

Check out this site for more info:

http://www.wirsbo.com/main.php?pm=1&mm=0&sm=0&pc=homeowner/ho_mm0sm0.php

 

[jheidt2543]

jachedup40,

Underfloor radiant heat has been around for a long time. You should be able to find a lot of information on the topic. You should also talk to a good HVAC engineer in your local area about the costs, design aspects and problems associated with it. It could be a good way to make use of your waste heat.

ERV notes a type of pipe he used. This is a VERY important point. Once the pipe system is under the floor slab there is little one can do to find and fix leaks. Twenty years ago a volunteer group, in our town, installed an underfloor refrigeration system for the local youth hockey program. They used black iron pipe. The system worked fine - for a few years, but now there are so many leaks that they can't find, the system is nearly unusable. Just a little horror story I thought I would share - in hopes that you will avoid the problem.

Don't forget that soil conditions can also affect the piping performance.

 

[Zambo]

I worked in Eastern Europe -Romania - for a while. They have thermal plants which provide heating to towns and cities. The only problem I found in my small apartment was that it was difficult to control the temperature and opening the windows in the middle of winter was often needed. In your case wouldn't piping the hot water around the plant keep the place warm without going under the floor slab?

Zambo

 

[ERV]

Addition to my earlier post. Currently designing 17,000 sq ft dental facility and surgery center, plan to incorporate hot water in slab radiant heating (AquaPex piping). This facility will have concrete exterior walls and conrete floor slab, no basement, and 1,200 sq ft 2nd floor medical record storage. Floor slab details will be worked out soon, so I will have more info on current radiant heating details in coming weeks, if interested let me know.

 

[cvg]

zambo has a good point. how will you install the pipe / tubing under the existing slab? This might be easier to construct using standard radiators either free standing or mounted along the walls. Above ground piping system will be easier to install and maintain.

 

[jackedup40]

I am looking at replacing some sidewalks, steps and a pad or two of existing concrete. I would like to try this out before we attempt to redirect the water to the interior of our offices as a heat source. If we can feasably do these easy areas I mentioned above, a lot of other areas inside and out will probably be looked at also.

 

[aspearin1]

Is there no summer at your facility? I presume you will always need to get rid of this water regardless of season. How will you keep temperatures reasonable for your employees during the hotter months if you put this "always-on" heat source through their work space?

aspearin1

 

[jackedup40]

It will not be an "always on" heat system. Looking for the best way to regulate the heat. Year round.

 

[RDK]

Just remember that with any hot water heating system there is a LOT of heat available in the system after the thermostat or regulating valve shuts down the flow.

You will usually overshoot the set point, especially if the outside temperature is rising. (Typical spring and fall weather).

You might want to set the hot water heat to a slightly lower set point than you want the area to be heated and then install small capacity trim heating systems.

Again a good HVAC engineer will know all this and most likely have some additional ideas.


Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com