HVAC chillers account for the largest electricity consumption in most institutional and commercial facilities. With that in mind, it makes sense to monitor and control the operation of HVAC chillers for maximum efficiency. Fine-tuning your mechanical and HVAC systems will save you costs in the long run. Here are a few steps to follow to improve the performance of your chiller operation.
1) As the load decreases, you can raise the chiller’s supply temperature, with a typical setpoint of 42 degrees F. If it is not possible to measure the demand conditions, then monitor the room temperature and schedule a setback when your building is unoccupied. Adjustments should be made based on outside air temperature.
2) You can also control the chilled water pump speed. To determine the KW consumed per BTU supplied, run a test and compare it to the cost to lower the water temperature. You may notice that the VFD at the far end of your system maintains a differential pressure.
3) Without running the compressor, a chiller can provide cool water. If you cool the water tower to 45 degrees F, then the refrigerant can cycle between the condensing and evaporation sides so that it lowers the chilled water by two degrees. Before the chiller in your HVAC system starts again, bring the condensing water back up to 55 degrees.
4) Controlling the chiller when it starts up is critical if you are paying for peak electricity usage. The chiller more than likely has at least one step, which can limit the maximum full load amps. The maintenance staff needs to know not to override this. Also, program the supply setpoint to limit the amps to the last maximum peak load.
5) Of course, there will be times when the system has to operate at full capacity or provide cooling without any regard to cost. Keep in mind you can program for specific areas in a building and for specific equipment.
For more information about HVAC chiller operations, contact Crockett Facilities Services – a commercial mechanical contractor and HVAC service provider for Maryland, D.C. and Virginia. Call 301.262.2771 or email us at sales@crockett-facilities.com. We’re In This Building Together!
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Drive Your HVAC System to High Performance