WHAT is CHILLER Maintenance and Service ?
Chillers often represent a plant’s single largest electric load. But factor in fouled tubes, leaking refrigerant, or myriad other factors, and operating costs can quickly escalate by 8% to 10%. Operating chillers at their peak performance will save energy and maintenance costs.
Chiller maintenance has advanced significantly, due to new developments in centrifugal chillers with magnetic bearing chillers, and new remote monitoring technologies. As a result of remote monitoring, the industry has been moving toward demand maintenance programs and away from pre-determined schedule maintenance.
Whichever program you use, here are 10 maintenance tips that apply to most centrifugal chillers, to help maintain high efficiency:
Keep a daily log
The daily log is still the first step toward maintaining an efficiently-run chiller plant. The log allows you to build a history of operating conditions including temperatures, pressures, fluid levels, and flow rates.
Keep tubes clean for efficient heat transfer
Heat transfer efficiency has the greatest single effect on chiller performance, so clean heat transfer is fundamental to maintaining high efficiency.
Treat condenser water to prevent scale, corrosion
All lead to fouling in the condensers and impede heat transfer and can decrease tube and piping effectiveness.
Lower entering water temperature
Lowering the temperature of the entering condenser water will improve the chiller’s efficiency.
Keep chilled water flow rate between 3 to 12-ft per second
Changing the chilled water flow rate affects a chiller’s performance.
Maintain adequate refrigerant charge
The actual amount of cooling a chiller provides depends on how much refrigerant it moves through the compressor. It is important to maintain the proper level of refrigerant for the conditions desired. .
Prevent inefficiencies caused by non-condensables
Non-condensables such as air and moisture leak into low pressure chillers because their evaporators operate in a vacuum. Non- condensable can lower the real efficiency of the chiller from the rated
performance by as much as 4% at 60% load and 7% at 100% load.
Analyze compressor oil
Send a sample of the lubrication oil to a laboratory for a “spectrometric” chemical analysis once a year.
Check operation of starters and motors
For efficient operation of starters and motors, check the safety and sensor calibrations on microprocessor controls (consult manufacturer’s
Install variable speed drives
The chiller motor is typically the largest single electrical load in a building. With the right operating conditions, variable speed drives (VSD) can offer
significant energy savings. VSDs reduce the mechanical shock of starting large horsepower motors, increasing chiller reliability, and life.
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