Water Chiller selection

[HuyLee]

Hi all:
i am designing HVAC system for a 700 RT pharmaceutical factory. But I don't know which selection of Chiller will be optimize the energy of the factory. I am thinking about two option:
1. Select 2 Chiller with 800-900 RT to run alternately.
2. Select 2 Chiller with 500 RT to run at the same time and 1 back up Chiller.
My Water Chiller has screw compressor. Can i have your advices.

 

[goutam_freelance]

Option 2 will be cheaper, however, maintenance cost may be higher due to the higher number of equipment.

Regarding screw compressors, for this cooling load, the centrifugal chiller may also be competitive. Ref below:
https://aircondlounge.com/centrifugal-chiller-vs-screw-chiller-chiller-selection-guide/

 

[moideen]

Choose two chillers with different capacities, such as 300 tons and 600 tons. Switching between these different-sized chillers is more efficient than using two of the same size at a lower load. During low load periods, the smaller chiller can operate at full capacity, resulting in maximum efficiency. The building's full capacity reaches about 1% of the time in a year.

 

[LittleInch]

First work oiut what the range of chiller capacity is over the year.

 

[SAK9]

You need to create an annual load profile for the facility with the percentage of operational time at each segment of the load profile. Once you complete the load profile you may see that the the building peak load occurs for less than 10% of total operation time. You need to find out from the load profile at what percentage of the building peak load the plant needs to operate at most of the time (quite often as high as 60-70%).By selecting the chiller at the part load operation point you will ensure the chiller operates at 100% of its capacity most of its operation time For example the if building load load for most part of the year is 600 tons, you must choose a 600 ton chiller and a 300 ton chiller