Storage of meat,floor defrosting and heat recovery

[MilosBog]

Hi All,
I am working on the project of storage facility for one supermarket in Poland. In the file disposition is drawn the evaporator positions, door air curtain and the Underfloor heating pipes. At the moment I am developing the idea and I would like to listen to the different opinions.
On the floor above is a room in which two condensing units are stored. One unit is for regime of 0 °C and another one is for -18°C.
For the piping concept I would like to use headers.
The condensing unit room-units are stored in a room so I will propose to install one grill and above condensing units I would design one air duct for exhaust air. In this would be installed air to water heat exchanger which is connected to the buffer tank. The water from the buffer will be stored until the frost is likely to occur on the floor in two rooms. I have found some controller for the snow melting and de icing from Velta. This controller will control the pump and the 3 way valve.
Underfloor heating-will be used un two rooms. The pipes shall be connected to one manifold in the hallway. The floor sensor will be connected also to the actuators on the manifolds so that normally closed actuators shall open up when necessary.
Door air curtain will blow a recirculated air, without any conditioning, just to prevent infiltration.
What do you think about this stuff? The thing that worries me are condensing units,
Should I use for each evaporator a separate condensing unit or this thing will be OK? I thought to use a Bitzer condensing units with two pistons so that capacity could be changed and also the condensing fan speed control.


All the things that you think that i have missed oranything else, please comment

[MilosBog]

Attachements

[Segei]

Don't locate evaporators above the doors. Put them on opposite walls like for CR5.

[MilosBog]

Thanks, i will do it in such matter

[Peter_1]

What is your intention in the freezer room with the radiant heating? Preventing frost on the upper floor?
If so, then this is completely wrong and it will never work.
Please, elaborate further because otherwise, there's a change you will make a huge mistake.

[MilosBog]

HI,
that was exactly my intention. To prevent freezing with 8-11Watts per m2 of underfloor heating. What is wrong? I have seen that it has been done in such matter in few projects. Could you elaborate it please? Thanks in advance

[Peter_1]

You need to heat the floor under the isolation, not the one above it. It will never work, take my word on it.
The upper floor acts as a large cold buffer. What will you do with the water on the floor in a freezer on -18°C?
it will become a skating ring.
You also add a huge load in your freezer, not very economical these days..
You don't have to worry about frost of the upper floor but frosting up of the lower floor. (frost heave)

[MilosBog]

As i come from AC i have proposed it in such matter. Where did you find this photo? Is there any particular literature for this matter or just experience is at the stake. I have seen some old projects which are done in matter of heating the upper level...Thank you, the help is appriciated

[Peter_1]

I'm 30 years in business, build several big freezers (+/- 50 x 30 x 12 m was the biggest one) so most is coming from experience. And keeping my eyes wide open when others are busy, the best learning school.

I posted here on Re some pictures I made of a failing radiant heating in a freezer (+/- 15 x 15 x 8 as far as I remember) which led to a judicial case in Court.

1° additional heat load which will needs to be removed continuously by the evaporators.
2° you will face a huge load because you continuously have to remove latent heat from the concrete and the water.
3° how you think you can warm concrete to 1°C when 5 mm above the concrete you have an air flow of -18°.
4° what about the fact that if you should reach a temperature of 1°C and ice becomes water on the surface, what will happen when circulation drops and the -18°C comes in contact with the water on the floor.

I wrote an article in French and Dutch for the Belgium Cool&Comfort Magazine about frost heave and how to prevent it.

Regarding you condensing unit: why you want to control the fans and how will you do this?
Will you install 2 Bitzer condensing units on 2 evaporators with each a capacity control on the pistons?

[MilosBog]

HI, i thought of using one condensing unit for two evaporators for a freezing rooms. I know that the condensing units shall work with full load only a bit and as i will have one condensing unit(no budget for two), the condenser fan speed control is I thing a must. |Is there any other way to regulate a capacity at the piston compressors? I am , as you can see, very new in this matter. Do you have a link to your article? I will give my best and Google translate also..
BR

[Peter_1]

Why is fan speed a must.
Search once here on RE for frost heave
for example http://www.refrigeration-engineer.co...ht=frost+heave

[MilosBog]

Hi,
the freezers are in Poland, so they will work on low outer temperatures. That is the reason that i want to use a fan speed control. TNX for the link, i will try to translate it on English so i will send you when it is finished.