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DHASHU
20-06-2005, 03:50 PM
HEY GUYS,
PLS BEAR WITH MY KNOWLEDGE OF A NOVICE IN REFRIGERATION SYSTEMS, WE ARE UNDERTAKING THE MANUFACTURING OF A NEW TEST PEICE AND DO NOT KNOW HOW TO GO ABOUT SELECTING A CONDENSING UNIT. I HAVE THE OPENING SIZE FOR THE REFRIGERATOR(24"X48"x22"), WE PLAN TO USE 404A AS THE REFRIGERANT, THE AMBIENT TEMPERATURE IS 86F-100F, AND THE TEMPERATURE WE NEED TO MAINTAIN INSIDE THE REFRIGERATOR IS 34F-40F.
I WOULD REALLY APPRECIATE ANY INFORMATION YOU CAN GIVE ME AS TO HOW TOO CALCULATE THE BTU/HR CAPACITY AND THUS ENABLING ME TOO CHOOSE THE RIGHT CONDENSING UNIT AND COMPRESSOR.
THANK YOU
ASH

Peter_1
20-06-2005, 06:55 PM
What is the purpose of this 'thing', this test peice?
What goods are brought in it?
Entering temperature?
Final required temperature?
Mass/hour?
Required cooling time?
Humidity level?
Doors and size?
How any times will they open?
Other heat producing equipment inside?
.....

Why R404a and why a condensing unit AND a compressor?

SERGIO ROD
20-06-2005, 11:04 PM
For What I Know R-404a Is For Freezers, Ice Machines, Margarita Machines An So On..., You Can Use A Condensing Unit That Uses R-134a For Medium Temp, The Compresor Is Already Included In A Condensing Unit..., All The Questions Peter Is Asking Are Very Important Facts To Consider, Because They Are Variables That Will Affect And Determine The Right Choice Of The Condensing Unit You Will Use... Do You Know The Size Of The Evaporator That Is In That Refrigerator Or Are You Gonna Use A New One...? Cubic feet...? the more information you can provide the more accurate the help will be....

DHASHU
21-06-2005, 01:27 PM
1:What is the purpose of this 'thing', this test peice?
IT IS TO BE USED AS A REACH IN COOLER FOR FOOD PRODUCTS IN A CAFETERIA.
What goods are brought in it?
STUFF LIKE SALADS ETC
Entering temperature?
38F
Final required temperature?
ANYWHERE IN BETWEEN 34F AND 40F
Mass/hour?
N/A
Required cooling time?
VARIES
Humidity level?
EQUIVALENT TO FOOD PRODUCES
Doors and size?
2 SETS OF SLIDIDNG DOORS 35"x20"
DOORS ARE INSULATED
How any times will they open?
CANNOT BE ACCOUNTED
Other heat producing equipment inside?
NONE
.....
THANKS GUYS
ASH
Why R404a and why a condensing unit AND a compressor?

frank
22-06-2005, 08:07 PM
PLS BEAR WITH MY KNOWLEDGE OF A NOVICE IN REFRIGERATION SYSTEMS, WE ARE UNDERTAKING THE MANUFACTURING OF A NEW TEST PEICE AND DO NOT KNOW HOW TO GO ABOUT SELECTING A CONDENSING UNIT

If you want to avoid problems later on I would honestly suggest that you employ an refrigeration design engineer at this stage.

There are many variables that you need to consider in the design, it is not as simple as selecting a condensing unit.

Peter_1
22-06-2005, 08:37 PM
Somewhat same question: I'm a novice in designing airliners.
I want to make an airliner which can fly from Belgium to Russia, non-stop, carry 50 persons and fly at FL350.
I want as much information as possible how to design the jet-engines.

wambat
22-06-2005, 11:34 PM
On the following parameters, I have come up with the following system for your project
For a cabinet temperature of 35/40*F and a volume of ~16 cu ft, a load of 1300btu/hr is given in “Heatcraft” calculations also the (2) insulated sliding glass doors are equal to about 1000btu/hr, all is based on a 16 hour run time total ~2300btu /hr. If the doors are not insulated then you need to add 1000btu/hr. So with the following in mind, I feel that the following condensing unit should do a proper job.

Copeland model# ASE20C4E-IAA
MT: Medium Temperature Rating Conditions
Refrigerant: 404A 40 Return Gas (F)
Voltage: IAA 115-1-60 0 Sub Cool (F)
20 Compressor Super Heat (F) 95 Ambient Temperature (F)
Production Status: Available for sale to all U.S. customers. Please check with your local Copeland representative for international availability.
Evap Temp (F) = 20 RLA = 5.2
Cond Temp (F) = 110 Half Winding RLA =
Capacity (Btu/hr) = 2370 LoLRA =
Power (Watts) = 451 HiLRA = 26.5
Current (Amps) = 5.3 Half Winding LRA =
Mass Flow (Ibs/hr) = 52 Max Operating Current =
EER (Btu/W-hr) = 5.3
Isentropic Efficiency = 42.8
Evaporator Superheat (F) = 20, Net Refrig Effect (Btu/hr) = 2370
If this is not to your satisfaction, then may I suggest you talk to the copeland people at the following
http://www.copeland-corp.com/cp_rf/cp_rf_.htm

gerryboy00
23-06-2005, 04:09 AM
The total refrigeration load is the total of the following “load segments”:

• Transmission Load - heat gain through walls, floors and ceilings.
• Air Change Load - heat gain associated with air entering the refrigerated space, either by infiltration or ventilation.
• Product Load - heat removed from and produced by products brought into and stored in the refrigerated space.
• Internal Load - heat produced by internal sources such as
lights, electric motors, and people working in the space.


....not as simple as you thought ;)

DHASHU
23-06-2005, 03:48 PM
thanks guys,
the information has been extremely helpful. shall let you all know if the prototype functions.
ASH

Peter_1
23-06-2005, 08:06 PM
Never thought it could be that simple.
Why on earth I ever read al those books?

Deejey
24-06-2005, 05:35 AM
I'm with you peter. think I'll just get all my refrig students to log on here..be easier than than having to teach them all the theory

DHASHU
24-06-2005, 01:18 PM
Hey Peter,
Well I Dont Know If That Was Sarcastic Or What, But I Did Have To Read A Lot Of Books Just To Figure Out What U Guys Were Saying.
Thanks
Ash

Vincent Yu
07-07-2005, 09:39 PM
I do agree with Peter. You had better to hire a refrigeration engineer to design it for you. At least you should ask someone to calculate the heat load for you. The information you gave is not enough to determine the heat load. At this point, it is impossible to select the right condensing unit for you.

There is one thing I want to piont out. If you want to keep the food temperature between 34F to 40F, I feel R134a is better than R404a.

wesmax
22-07-2005, 03:24 AM
first why r404 at the amb you are running your head is going to be out of sight. use a drop in i dont know where you are so dont know what is sold here i would use r22. size would be hard to tell not knowing how the cooler was built. Here i would use a 1500 BTU coil and match compressor at 20 deg sst.
wesmax