How can I get lower temp?

[meister]

If I drop condenser temp by switching from air to cooler tower water on the condenser of my HVAC unit, will I get a lower evap temp? I'm trying to get a lower cooling temperature on my process fluid that I am cooling. Thanks!

 

[chicopee]

Thinking about the refrigeration cycle, it seems that the low pressure side temp could drop, however, you could also get saturated vapor instead of superheated vapor in the compressor. Should I say more about potentially damaging the compressor when compressing liquid.

 

[ChasBean1]

No.

 

[quark]

If the TEV works properly I don't see any problem with saturated vapor at compressor suction. Lower condensation temperatures generally help you getting better performance and efficiency. Just check with the manufacturer about the design details.

 

[ProfSporlan]

Lowering condensing temperature will both lower the enthalpy of refrigerant liquid, and the pressure ratio across the compressor unit increasing its efficiency, provided the TEV is sized to handle the lower condensing pressure.

For any system employing a TEV, one can expect some capacity and efficiency gains with lower head pressures. Lowering head pressures substantially, however, requires one to consider system design issues.

 

[jcavti]

Hello,

Tell us more about the process (eg. temps, product, schedule,...)
How is it today? How many degrees you should drop?
What is the optimal cooling temperature? What's the process fluid?

I believe that you could get more practical answers.

Stay Cool...

 

[ChasBean1]

Air cools the unit now. After change, cooling water, which is cooled by air, cools the unit. Compressor work and COP may change, but I don't see a difference significant enough to change the low side pressure that determines the evaporator temp.

 

[pennpoint]

meister;
As noted in profsporlan's post, what will result for sure is an increase in efficiency and added capacity (in that order) of your current system but would not lower the evaporator temperature all that much.
For a real reduction in evaporator temperature you will likly need to change the refrigerant which could mandate changing out the compressor and other components such as the txv (thermal expansion valve). You do not say where you are and where you want to be as far as evap. temperature. It would be of instrest to know more about your requirements.

pennpoint

 

[anandHVAC]

As per my opinion it is possible to get the lower evaporator
temperature but not because of lowering the condensing temperature. By lowering the condensing temperature to acceptable limit(Refer manufacturer data) you can increase the refrigerating effect(TR).Refer enthalpy-Entropy chart for a particular Refrigerant.
If you want to lower the evaporating temperature, your compressor will derate i.e refrigerating effect will reduce.
How much deration or lowering of evaporating temperature is allowed varies with type of refrigerant. Also you will have to check your TEV for revised parameters.
Hope I have clarified your queries.