choose right air cooling chiller

[yfuo28]

Hello everyone,

For the first time I have to choose from the catalog air cooling chiller.
I have the water temp. (in and out) of the chiller, I also have the ambient temp. & RH and the load from the building

I want to calculate the chiller's cooling power in tons.
Some one can please help me with this and give me a short guide?

thx!

 

[yfuo28]

Maybe I'll be more clear,
How does the temperature and relative humidity of the environment affect the selection / calculation of the chiller?

 

[willard3]

This is not a course in Thermodynamics, it is a web forum.

If you have to ask such basic questions, you need help from a senior engineer.

 

[LittleInch]

Well it depends what sort of heat rejection device you are using.

A cooling tower is impacted by temperature and RH

A finned heat exchanger more by temperature than RH, but you would need to look at the catalogue more closely.

I suggest you put down what you know and which chiller you intend to use with the catalog and then people can let you know if you've chosen the correct one.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Emrelug84]

Hello yfuo28,

There are more parameters than you think, it affects chiller performance directly and indirectly.

Firstly, air temperature is the parameter that you should think since your water circuit is cooled with air. As air temperature is low, chiller performance is increasing because colder air cools more, it is simple. As air temperature is increasing, chiller performance gets worse. There is usually a restriction in air maximum temperature that you should take into the consideration. When air temperature reaches the max. value for chiller, chiller stops working since the pressure in evaporator is high. The max. air temperature will be written in the product catalogue. This is important. Keep in mind!

Secondly, cooled water temperatures are the parameters that you design. (for example, 6/12oC, 8/14oC) These values also affect chiller performance because of LMTD (log mean temperature difference). I strongly suggest you to search LMTD phenomenon.

Thirdly, chiller installation is another important issue, you can easily find the suggestions from catalogue.

Finally, altitude is another parameter that you consider since it affects the atmospheric pressure. When seleceting chiller, you shoulg give that data to vendor.

I hope these give you an idea. These topics are very interesting and enjoyable to search.

Regards,
Emre

 

[lilliput1]

Chiller size should match the diversified cooling load of each chilled water air handling units and fan coil units served plus chilled water pump heat + pipe insulation loss + allowance for future load expansion. If cooling is critical consider adding spare chiller and associated equipment (pumps, cooling towers). Note centrifugal chillers optimum operation is at about 50% load so it could be beneficial to operate both chillers.