Jun. 10, 2024
Mark Hanson, service technician, finishes a maintenance job on a centrifugal chiller by verifying that actual conditions match performance specifications.
Contact us to discuss your requirements of Ai Chiller Plant Optimization. Our experienced sales team can help you identify the options that best suit your needs.
Control water velocity
Flow rate must be regulated closely, because too low a flow rate reduces chiller efficiency, leading to laminar flow. The minimum flow rate is typically around 3 ft. per second. However, too high a flow rate leads to vibration, noise and tube erosion. The maximum recommended flow rate is typically around 12 ft. per second.
Maintain refrigerant charge
The amount of cooling that any chiller can provide depends on how much refrigerant it moves through the compressor per unit time. It's important to maintain the proper level of refrigerant.
Leaks, as well as air and moisture, decrease efficiency and system reliability. Low refrigerant charge, usually resulting from leaks, causes the compressor to work harder and achieve less cooling effect.
Purge non-condensables
Air and moisture are two non-condensables that can leak into low-pressure chillers. Non-condensables can reduce chiller efficiency by as much as 4% at 60% load and 7% at 100% loads.
Air insulates tubes, preventing exchange and elevating condensing temperatures, which also makes the compressor work harder. Moisture promotes acid formation, which can damage motor windings and bearings.
Installing purge units on low-pressure chillers minimizes the effect of non-condensables. Modern, high-efficiency purge units minimize both air ingress and refrigerant loss.
Eventually, positive pressure chillers using HFC-134a, HFC-410a and HCFC-22 will replace low-pressure chillers. The newer units don't require purge units because non-condensables can't enter them.
Analyze compressor oil
Once a year, send a sample of the compressor lube oil to a laboratory for a spectrometric chemical analysis that will provide details about moisture content, metals, acids and other contaminants that affect performance. Oil should be replaced only if necessary.
High moisture levels can indicate a purge unit problem, which has a significant effect on efficiency. Pull samples from low-pressure chillers more frequently, using a schedule based on purge run hours. Replace oil filters when they exhibit a high pressure drop and when the oil charge is replaced.
Check wiring
For efficient starter and motor operation, check the safety and sensor calibrations on microprocessor controls. Consult manufacturer's guidelines. Then check chiller electrical connections, wiring and switchgear for hot spots and worn contacts. To prevent insulation faults, test motor windings for resistance to ground and winding-to-winding. Check the shaft seal on open drive motors for possible refrigerant leaks, and clean motor cooling air vents to maximize cooling.
Modulate speed
A chiller motor is typically the largest single electrical load in a building. Constant-speed compressors match capacity to load through inlet vanes, throttling the gas allowed into the compressor impellers. This is not the most efficient way to modulate chiller capacity.
Under the right operating conditions, variable speed drives offer significant energy savings. Variable speed drives also act as "soft starters" to reduce the motor's inrush current to almost that of the full-load running amps. This reduction is important for chillers operating on emergency power generators. Variable speed drives also reduce the mechanical shock of starting large horsepower motors, increasing chiller reliability and life.
Richard Grenz is national sales and marketing manager for McQuayService in Minneapolis. Call him at (763) 553-.
There&#;s a lot of pressure on individuals, businesses and organisations to increase plant reliability, reduce energy consumption and lower the carbon footprint of their operations on the environment.
In most applications, chillers are the single largest energy consuming piece of equipment within a building.
Suggested reading:
If you are looking for more details, kindly visit Custom Chiller System.
By increasing the efficiency of your chiller plant, you can expect to:
Here are 5 ways you can increase the efficiency of your chiller and make energy savings:
Over or under charged refrigerant circuits can lead to a ~9% reduction in energy consumption.
Cleaning a heavily fouled chiller condenser could lead to an energy saving of up to 10%, compared to a lightly fouled chiller condenser where you could expect to save 1-3%.to a ~9% reduction in energy consumption.
By replacing a thermal expansion valve with an electronic expansion valve, energy savings of around 14% are possible, but this varies on the loading of the chiller.
Replacing the fans of an air-cooled chiller, air handling unit (AHU) or cooling tower can lead to an energy reduction of around 6%.
They can be replaced by EC fans, or by the addition of an inverter. The same goes for water pumps. They can either be swapped out for new, high efficiency units, or an inverter can be added &#; this will save energy by up to 25%.
When the outdoor temperature is below the chilled water set point temperature, heat can be removed from the cooling system without the use or with minimal use of the compressors.
Free cooling can reduce the chillers annual energy consumption by as much as 20%-50%.
To find out how much energy you could be saving on your cooling equipment, while increasing its lifespan please call us on 004 or .
Download the tips here.
For more information, please visit Small Temperature Difference in Chillers.
If you are interested in sending in a Guest Blogger Submission,welcome to write for us!
All Comments ( 0 )