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clint84
24-07-2013, 06:31 AM
Hi,

I'm new to this forum and I have a question about the specific heat of R134a during the condensing phase in the refrigeration cycle.

I am currently trying to assess the impact of increasing seawater inlet temperature (as cooling medium) on the cooling capacity (Q) of the Chilled water plant. I have estimates for mass flow but i can't find a figure for specific heat for R134a at 70 deg C as it enters the SW condenser. So far i have only found the specific heat of R134a at 0 deg C saturation which is 1.34 kJ/kg.K.

Secondly, this may be a silly question but would I be correct in assuming that the specific heat of R134a changes as it condenses at 40 deg C at constant pressure as an example. How do you account for the temperature glide as the refrigerant is superheated at 70 deg, condenses at 40 deg, and then is sub cooled at 30 deg C???

Sorry so many questions but i would appreciate if someone could help me out. :)

Cheers

Clint

Josip
24-07-2013, 09:47 AM
Hi, clint84 :)

Welcome to RE forums ...



Hi,

I'm new to this forum and I have a question about the specific heat of R134a during the condensing phase in the refrigeration cycle.

I am currently trying to assess the impact of increasing seawater inlet temperature (as cooling medium) on the cooling capacity (Q) of the Chilled water plant. I have estimates for mass flow but i can't find a figure for specific heat for R134a at 70 deg C as it enters the SW condenser. So far i have only found the specific heat of R134a at 0 deg C saturation which is 1.34 kJ/kg.K.

Secondly, this may be a silly question but would I be correct in assuming that the specific heat of R134a changes as it condenses at 40 deg C at constant pressure as an example. How do you account for the temperature glide as the refrigerant is superheated at 70 deg, condenses at 40 deg, and then is sub cooled at 30 deg C???

Sorry so many questions but i would appreciate if someone could help me out. :)

Cheers

Clint

If you take a time to search RE forums for sure you'll find your answer and much more ....

There is no silly question/s, but sometimes answer/s can be silly, see my sig ;)



anyhow ... check with Google for CoolPack program .... free and mighty to give you a lot of possibilities to virtually play with any refrigeration plant you like ...

There you have Log(p)-h diagrams, T-s diagrams, h-s diagram, saturation table for many refrigerants and much more .... you can see and plot your refrigeration cycle .... I believe you'll like it ... enjoy;)

Hope this will help you ....

Best regards, Josip :)