Energy saving with PHE for air cooled chiller

[moideen]

There are lot of thinking and ideas on energy saving in hvac system, here an idea dawn in my mind, I don’t know whether it is work out. In my case, an air-cooled chiller placed on rooftop, I want connects its compressor discharge line in to compact type phe. Primary cooling water to PHE used by building water tank nearby. I have not calculated any capacity of phe,pump…etc.. This is just outline thought…what you think ….thank you

 

[lukaiENG]

Proceed with caution.

If I understand correctly, you're effectively talking about converting an air cooled chiller to a water cooled/air cooled hybrid chiller. My first reaction to this is "don't do it!"
My second is I wonder how the chiller will cope with this from a pressure perspective - both overall static and head pressure. adding in a separate cold heat exchanger prior to the evaporator may run the risk of sub-cooling the refrigerant outside of the machines normal operating characteristics.
It will also adds another component of pressure drop to the system which will affect capacity - possibly offset by the additional subcooling.
You also need to factor in what happens to the temperature of the water tank, and if you are creating a potential breeding ground for microbio by elevating the temperature.

You will need to consult carefully with the equipment manufacturer before making any modification to their equipment. Not doing so will void warranties, you will run the risk of voiding warranties anyway I imagine.

If you're really interested in increasing efficiency of an air cooled chiller, you are better to add free cooling/economization prior to the chiller. You can do this by piping in a dry cooler (or cooling tower via PHE) into the chilled water system prior to the chiller to act as a pre-cooler . This way you can reject heat (admittedly for less hours per year) without running your compressors. Or, if you're dead set on using this water tank, pipe a PHE into the CHW system prior to the air cooled chiller and add a heat pump to increase the grade of the heat to maximize your hours of operation.