Choosing quantity of evaporators for a cold room

[nightfalc]

Hi,

Can I tap the brains of the experts here? How do you decide on the quantity of coolers for a specific space? e.g. 1X3kW / 2x1.5kW / 3x1kW? I believe to ensure that cold air reaches the sides as well there should be a max. distance between wall and cooler OR cooler and cooler? should the sizing be based on Air changes for the space? Thanx in advance.

[ice_cool]

Hi, there're different types of commercial & industrial evaporating coolers (https://www.coolplusref.com/cold-room-condenser-evaporator-refrigeration-units.html) with different air circulation distance. You may need to check the parameters of the coolers and decide according to the cold room size.

[sterl]

If you are NOT actually cooling the product...the first consideration would be, is defrosting required? You always want at least 2-coils in a space where a defrost cycle is applied or the increase in temperature during defrost will be intolerable in most cases.

Additional considerations: Do you have walls or ceilings of the space that could encounter outside temperatures colder than the space? If so, condensation could form on walls or ceiling and air circulation, as well as dehumidification capacity will be required to remove it, which is to say, convey it to the evaporator coils. In doing so, the relative humidity of the space will be reduced, which may be detrimental to product contained...

Another consideration: If you have a big door and vehicle traffic into a relatively small space, you will have condensation and temperature issues around the door, presuming it is hot and humid on the exterior of the door. This can effect the selection of evaporators as well as their orientation.

And: What happens should a fan motor fail? Not only do you need access to the evaporator, but you will need a motor....Similar access/service topics for the control valves?

Each evaporator, at a given operating temperature, has a corresponding air throw to a (reduced) air velocity. In some cases this is a short distance because the proximity to working personnel would make a specific area intolerable for full time work station. In purely storage areas it tends to be a longer distance but high velocities at the immediate discharge of the evaporator can also cause product degradation. If the evaporator air discharge is a couple of meters above the product, this is largely a non issue but if product and evaporator are at more or less the same level it can be a considerable issue with rind fruit, exposed bakery products, grapes and similar....

Cold storages, operating below freeze temperatures, with suitable product wrapping and protection and a clearance above the product stack, can operate pretty well with "free" air throws up to 50 or 60 m. Coolers with wrapped/ enclosed/ bottled or otherwise insensitive products typically keep free air throws at more like 10 to 20m. If real gentle air flows are required ducts may need to be applied but cleanliness issues with most food products results in a different round of maintenance concerns; sooner or later the inside of the ducts will need cleaning and the exposed and insulated side is prone to damage from operations.

[nightfalc]

16051

Hi,

Thank you for the reply. Actually I am concerned about the "dead zone" as indicated in my drawing. How should we select evaporators to ensure that air distribution reaches most of the space? Is there a maximum distance between the evaporators or between the evap and walls?

[RANGER1]

Nightfalc,
Some ideas on how to mount.
You do not show position of doors in your sketch though


Placement Position | Refrigeration Unit | Cold Room Installation | Evaporator | Condensing Unit - YouTube (https://www.youtube.com/watch?v=rYk5u57Hw-k)

How high can you stack the product relative to a cold room evaporator? | Ask an Expert - Bing video (https://www.bing.com/videos/search?q=positioning+of+refrigeration+evaporators+in+a+cool+room&docid=608055446762430511&mid=6CF22DAFCB62DC49502B6CF22DAFCB62DC49502B&view=detail&FORM=VIRE)

Microsoft Word - Successful Refrigeration Depends on Good Airflow.docx (colmaccoil.com) (http://www.colmaccoil.com/media/44174/successful-refrigeration-depends-on-good-airflow.pdf)

[nightfalc]

thank you! this was very helpful! :cool::cool:

[nightfalc]

thought about the issue again and realized the advise was for minimum distance and not maximum between evaporators? let's say we ignore doors. is there a maximum distance between evaporators before the "dead zone" becomes too drastic?

[RANGER1]

Nightfalc,
I think we need real room & evaporator dimensions to comment.
Room temperature as well if you have not supplied already.
There are a lot of ways to do things.

[nightfalc]

16052
Height 6m. how would you configure the evaporator?

[RANGER1]

nightfalc,
To me lengthways with 1 unit at end of room.
Others on forum may have there input.
Suggest you go to evaporator supplier to select unit with required amount of fans that have enough air throw to reach end of room, as well as required capacity.
Suppliers can offer 1 to probably up 6 fan units, of go 2 units.
Let supplier do some work as well to help you make decision, giving them all the information.
If a freezer make capacity at least 50% bigger than required to allow for ice build up.
If you had 2 units side by side does not matter how close they are, as long as air is not restricted on inlet & outlet.
If freezer & electric heater defrost, allow for heater replacement.
See below link, someone like this should be able to help you.

https://www.thermofin.de/en/general.php

[nightfalc]

thanx heaps! how about distance apart? Is there a distance between evaporators after which we run into dead zone issues?