Calculation of "U" in Evaporator design

[anup]

In Air Source Heat Pump, while designing the evaporator, how to calculate "U"?
Whether high ambient temp (incidently which is used for refrigerant evaporation and India it could go up to 48 deg. C) affects "U"?
Thanks in advance for your valuable advice.
Regards
Anup

[Lc_shi]

contact evaporator manufacturer,they can provide the data for u. or get the software for selection. The simple way is to design on basic data(U is around 30~50w/m2.k which is related to your manufacturing tech or materail etc）but you need to do some test and get your own data. If you want more help,pls list your design reqiurement. perhaps we can do some help.

rgds
LC

[lana]

As you may know U factor in the heat exchangers is the most difficult parameter to evaluate. If one of the design parameter is changed then U will be changed.
There are so many equations developed to calulate U factor. Each one is good for a range of applications.
In real life these equations are modified according to the test results and they are used in computer softwares. The reliable and accurate ones are very very expensive?!!!
Try (If you can) HTFS software ACOL. You must be a member in order to use this software and the membership fee is too much. But in my opinion it is hte most reliable and accurate one. The company is called Hyprotech.
Cheers.

[Victorman]

Hola ! ANUP

Maybe this will help.

http://www.hvacindia.org.in/journals/2002oct/article01.html

Victorman

[Lc_shi]

Hi Victorman
It's a real good site. i‘ve never checked India's web.
hope more good links-:) thx

rgds
LC