aircooled chiller & water cooled chiller performance /derating

[navas72]

Dear member,
i wish to know the performance of aircooled chiller & water cooled chiller when the opearting condition is different from the design condition.
(i.e) when the dry bulb(air cooled) or wet bulb( water cooled chiller) is different from the design condition.
also what will be the impact when the aircooled chiller condensing coil is choked(dirt deposit) or not maintained properly.
is there any graph or article explaining this query in details.

 

[trashcanman]

The chiller catalog should have correction factors for different outside air temperatures.

When the condensing coils are clogged, performance goes right into the dirt. The unit will probably shut off due to high head pressure (refrigerant is not condensing).

When the unit is not maintained properly, performance also goes right into the dirt and can result in expen$ive repairs.

 

[navas72]

Dear members,
i came to know about this. is there any illustrative examples or articles regarding this.

A dirty condenser coil that raises condensing temperature from 95°F to 105°F cuts cooling capacity by 7 percent and increases power consumption by 10 percent, with a net (compressor) efficiency reduction of 16 percent

 

[KiwiMace]

If you want to deep dive into this: look up the recent ASHRAE research project RP 1275 Final Report. It'll tell you more than you ever wanted to know about the relative effects of faults on chillers.

ASHRAE technical committee TC 7.5 has churned out a tonne of fault diagnostic related studies.