Freezer Room Design

[MazlanZ]

Dear All,

Is there any design standard where to install the evaporators units in the cool rooms ?.

what we have here the the evaporators was install on the top of the door, so every times when the door open the evaporator will suck the outside air into the room & moisture will condense at the evaporator fin coil & form the Ice-wall & reduce the freezer performance.

Even the system is having the defrost cycle, we still having severe blockage over period of time since our enviroment huminity is 80%.

From my observation most of the freezer room design was having the evaporators at the end of the cool room or at the side away from the door. In this condition I'm notice, whe we open the door the positive pressure will blow-out toward the doors.

beside the best practice, I need to look for some standard or article by the expert to convince my management the by relocate the evaporator units away from the doors will reduce the amount of moisture being suck-in.

[NoNickName]

Whenever possible, refrigerating air-cooling units should be
located away from enclosure entrance doors and passageways. This
practice helps reduce coil frost accumulation and fan blade icing.
The cooler manufacturer’s installation, start-up, and operation instructions
generally give the best information.

Refrigeration, CHAPTER 42
FORCED-CIRCULATION AIR COOLERS
2006 ASHRAE Handbook

[acnerd]

On some of the small walk-in freezers and fridges I use to install, we would put in evaporator fan-stop switches on the doors. So the evaporator fan stops sucking in too much ambient air. Of course the compressor still runs, so we always ensured the customer was aware not to leave the door ajar for too long. Quite handy on small units where you haven't got a lot of location choice.

[B G Scott]

On some of the small walk-in freezers and fridges I use to install, we would put in evaporator fan-stop switches on the doors. So the evaporator fan stops sucking in too much ambient air. Of course the compressor still runs, so we always ensured the customer was aware not to leave the door ajar for too long. Quite handy on small units where you haven't got a lot of location choice.
In the old days, we used to interlock the fan with the interior light, so that when the light was on the fan was off.
We had one major complaint from a Mr Noah on the ARK he his staff kept leaving the light on and the fan off.

[nike123]

Nearly all unit coolers are ceiling-mounted
and should be placed (1) so they do not discharge air at any doors or
openings, (2) away from doors that do not incorporate an entrance
vestibule or pass to another refrigerated enclosure to keep from
inducing additional infiltration into the enclosure, and (3) away from
the airstream of another unit to avoid defrosting difficulties.

..............................

[shieldcracker]

Standards for evaporator placement? I never seen one, very typical of the refrigeration trade.

Besides ASHRAE try NSF #7 if the freezer has edible products, and try Heatcraft refrigeration manual.

[multisync]

Door or air curtains should be fitted as a std in that enviroment

[powell]

Follow this link and open the "Heatcraft IOM" link. Page 3 has your answer.

http://www.hvacrinfo.com/loadcalcs.htm

[botrous]

Dear Sir,

Please view the attachement
Best regards

[suny]

It is quite strange that the evap position. Best solution is to relocate the evap. Install an electric or PVC air curtain. If you are constraint with space in the cooler, you can interlock with the door and evap fans. But you have to be very careful here. The compressor will flood with liquid. Do not take this risk. Cut off the solenoid valve and evap fans when the door is opened. Then the system will get pump down and stops. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>