Refrigeration floorheating

[klaverlover]

Hello all,




I have a question that maybe one of you can answer.
Sometimes we need to lay floorheating for a industrial freezer, now my question.
For a blast freezer we lay the floortubes at 20 cm from each other, but for a normal freezer we lay them 50 cm from each other. Even when they work on the same evap temp.
Same thing with the isolation, sometimes we lay it 7cm thick and othertimes 20 cm thick.


Has that something to do with the glycol solution/watertemp that flows trough the floorheating?
Or is there no standard for floorheating.




Thx in advanced,
Klaverlover

[Lowrider]

It has to do with the amount of watts needed. In floor heating in houses or office's the distance is 15 cm and the heating delivers 125W per m2, from the top of my head!

[Peter_1]

Klaverlover, welkom op ons wereldwijde forum. Finally a new Belgium member among us.
Long time we heard something from BESC5240.

Mag ik vragen, voor welk bedrijf werk je of van welk bedrijf ben je de zaakvoerder?

This is realy coincidence, I just wrote a technical article about this topic (+/- 3 or 4 pages) in the new C&C which will be published within some weeks.
For those interested - it's written in Dutch of course - I can post the article here or on an external server.

I there give some practical guidelines.

I also published some pictures of a froozen-up floor where the heating system failed, or better, was wrong engineered. (Veurne, langs de autostrade om meer precies te zijn)
These pictures were already posted somewhere on this forum.

There's no standard about this but there are some good guidelines and practical experience gained over the years.

In my opinion, the purpose of the application doesn't matter how far the tubes are spread in the underfloor.
The temperature in the freezer and the blast freezer is approximately the same. Anyhow, a difference from 20 cm to 50 cm is to much. Especially when a circuit should fail, you don't have any redundancy at all.

Isolation for an industrial freezer of 7 cm is not enough, at least 20 cm in 2 layers, seams not over each other.

Minimum = 7 to 10 W/m² (23 -> 34 BTU/h) and 20W/m² (68 BTU/h) to have some redundancy.

[Lowrider]

@ Peter_1: Do uou remember where the pictures are? Would like to see them and also read your article!

Thanx in advance!

[taz24]

This is realy coincidence, I just wrote a technical article about this topic (+/- 3 or 4 pages) in the new C&C which will be published within some weeks.
For those interested - it's written in Dutch of course - I can post the article here or on an external server.
.

Hi Peter.
I would be very intrested in reading the article.

Thanks taz.

[Peter_1]

http://www.refrigeration-engineer.com/forums/showthread.php?t=3965

As soon the article is published, I will post it. Remember me within some weeks.
It looks better if I post it the way it's published. I just give my raw text together with the pictures.

[US Iceman]

Here is some miscellaneous information I found.

http://www.bylinusa.com/cold_storage/frost.html

http://www.thermonfibreform.com/us/catalog/us_pdf_files/CPD1038.pdf

http://www.fao.org/docrep/003/V3630E/V3630E08.htm

Apparently, there is more public information available on electric heating for this purpose than warm glycol.:confused:

[Lowrider]

Perhaps because they want to sell the stuff? But why buy electricity when you have plenty of heat supplied by sytem!

And then saying the electric system is more efficient!

[US Iceman]

Perhaps because they want to sell the stuff? But why buy electricity when you have plenty of heat supplied by system!


No doubt you are correct. I only posted the information in the hope that someone might find some useful information.

I am certainly not advocating the use of primary energy consumed for this purpose as that would be absolutely crazy. I agree with you, there is enough energy coming out of a refrigeration system to be used for floor heating without paying for energy twice!

[Sledge]

I have worked on a cold storage facility, which was built with ducts under the floor, through which they blew air, ambient in summer, and heated air in winter. They used gas fired make-up air units to maintain the floor at 1-3 degree F.

That facility was a 14 story frozen food warehouse with 6 automated stacker cranes, storing 50,000 skids at -20F. They have 2 blast freezers at -40F. There are 7 engine rooms, all ammonia.
They had more than enough sources of heat, but viewed it as more cost effective, and also more reliable, plus less headaches to use the gas fired makeup air unit.

Maintaining the floor at those temperatures was not a huge energy consumer.

[Peter_1]

This is the link to the article.
It will stay there 14 days after the last download of someone.
The publisher gave me the pdf file of my article but forgot to add the last page.
I will repost it after he gave me the complete version of the article.
http://www.megaupload.com/nl/?d=FPMDCXPY

[smpsmp45]

We are building a 60 m x 60 m x 12 m cold store complex with racking, Linde MHE, ( 5 Nos) , for -25 deg c in Mumbai India. panels & doors are from Germany , Raking from Spain.

We generally provide floor ventilation pipes being the most economical in terms of power. We have also used heaters, elevated floors etc. But 90% of our projects now use Ventilation pipes

[Peter_1]

If you are speaking in terms of power, then underfloor heating via a HE in the discharge or liquid to the freezer is without any doubt the best way.
This can be proven thermodynamically.
You have to see this much wider and spread the eventual higher investment over a longer time and especially when you can increase seriously the COP.

And especially in your country with it's high temperatures

[smpsmp45]

That is right. Infact as I can see, the floor heating/ pipes etc started in India may be in the last 15 years or so. I have seen no of old cold stores where in this point is not at all considered. Many a times to match the loading dock heights for container docking , the cold store needs to be built over elevated floors. I remember this point was discussed over a no of times when we were building the coldstore for Lever Ice cream factory. The Lever specs did call for Heaters, but eventually due to site conditions, elevated floors were used