Capacity varies or not

[harsha.hv88]

Dear friends,

I have a doubt regarding the capacity of compressor and the fixing of suction temperature. If we are having a plus temperature (say 1 degree celsius as suction) system with an economizer in it , the system is normal.

If we have to make it for negative application say -10 deg C then what is the procedure simply adding a Expansion valve in between the exact place of the system give you the temperature or any other changes has to be made.

[RANGER1]

Harsha,
Simply lower suction pressure set point.
It will decrease compressor capacity a bit as gas is not as dense.
So as long as you have enough compressor capacity to achieve the lower pressure the system will find a new balance.

Tell us why you want to lower it & your system, as it may vary the answer a bit.

[harsha.hv88]

Thank you so much for your valuable reply......ranger1


My customer is having a chilled water plant now and he requires the plant to used with glycol in order to bring some new products into their cold room or cold store. so he asked me to help me out.

Initially he had some food stuff like veggies and some fruits but now he is thinking to divide the room and bring some milk to be stored there and how about the controls for having separate temperatures without any imbalance in the system...........

[RANGER1]

harsha,
The main thing to consider if your room temperature is close to or below zero, is defrost of air coolers.
If 2-3 deg C off cycle defrost, which is close liquid line solenoid at required room temperature, but keep fans running.

If room temperature is lower, possibly defrost heaters or something may be required.
If running one room at a lower emperature than other/s, a bacsure regulator can be used on the warmer room.This prevents frosting of air cooler as well as less moisture removal from product due to less temperature difference between room temperature & product.

My comments are only general as do not know exactly your circumstances.

[harsha.hv88]

Dear Ranger1

a very much worthy reply.

i have a new doubt is there any refrigeration certificate courses for Engineers, can you please specify it with all sort of details. I have my Bachelors degree in Mechanical Engineering from INDIA and working in Johnson Controls International.

with regards,
harsha