A discontinuous refrigerant cycle

[LEO31]

Hi there, I went to a learning visit to a small plant where it was intended to use a refrigerant cycle to cool down water used in a heat exchanger; from what I've gathered they had to stop using the refrigerant unit altogether as they're doing little batch productions per day, resulting in having to turn off the unit multiple times per day. During the shutting down phase the water sub cools as it has nothing to exchange heat with (as the batch has already ended and the heat exchanger is empty).

My professor didn't have an answer for me, is there really no way to resolve this and being able to use the refrigerant unit accounting for the final transitionary phase ? Thanks

 

[russ_watters]

My professor didn't have an answer for me, is there really no way to resolve this and being able to use the refrigerant unit accounting for the final transitionary phase ?

I don't understand the question (maybe your prof didn't either?). Resolve what? Use the refrigerant unit for what? When you stop needing it you turn it off and it stops working....

 

[LEO31]

From what I understood while turning the refrigerant unit off the water cools too much as there's no more product to exchange heat with. This sub cooling effect makes the fluid unsuitable for the next batch and allegedly it's the reason why they are not using the unit anymore. Obviously this wouldn't be a problem if the process was continuous but they now switched to a batch production. Hope I made my self clearer

 

[Tom.G]

Shut off the cooler shortly before the batch ends,

OR​

Add a heater to reheat for the next batch,

OR​

Sell the chiller on the Used Equipment market.