How efficient are air cooled chillers?

For some of us who have air conditioning chillers at home or industrial chillers in the offices, there are questions waiting to be answered. Only a few of us know how they truly work and there’s one thing that boggles the mind. When it comes to air cooled chillers, energy efficiency has become an ambiguous term.

Air cooled chillers remove heat from water or other fluids. This heat is then dispersed into air through a system called refrigeration.

It all starts when a fluid is forced with high pressure through a tube. This changes the fluid to turn into gas which absorbs heat through the evaporator heat exchanger. This gas then travels to the compressor where it is compressed into a hot gas before being pumped to the condenser. In the condenser, the gas is passed through small copper tubes with thin aluminum fins bonded to them. When ambient air is forced through the condenser via the process chiller’s fans, the gas is condensed back to a liquid state. In this process, the heat that the gas has collected is released through the chiller fans as well. The liquid is sent back to the tubes so that the whole process can start again.

The efficiency of an air cooled chiller depends on the efficiency of the chiller compressor. This can be measured through COP or Coefficient of Performance. A COP is the ratio of heat removed to the electrical input required. In chiller efficiency, the higher the COP is, the more energy efficient it is. If a COP is 5, it means that for every 1 KW of electrical energy input, 5 KW of heat is removed. If a COP is 10, it means that for every 8 KW of electrical energy input, 8KW of heat energy is removed.

Check out the COP of the chiller the next time you’re out chiller shopping. You can now tell the difference in terms of energy efficiency.

Chiller Maintenance

Chiller maintenance is an essential and critical part of having and owning a chiller. Chillers need special attention and care to fully maximize their performance and efficiency longer. They don’t come cheap thus should be kept in good condition. There are specific handling techniques in taking care of used chillers. Here are some of them:

- Keep a daily log that consists of the different operating characteristics of your chiller. This gives you an overview of its dxlay to day performance.
- Before the cooling season, check the starter and controls of your chiller.
- Make sure the interior of you chiller is clean and in proper condition:
• No litter, dirt or any kind of debris.
• All the wiring connections are tight.
• All linkages move freely.
• Overloads are set correctly and are functional.
- Double check to see if the safeties and controls work. They all should work.
- Do a careful and thorough inspection of the compressors every so often.
• Check the compressor oil level and filter. Change them as often as the manufacturer’s guidelines say so.
• Have the oil sample examined to check for destructive acids and corrosive materials.
- Make sure the crankcase heaters are functioning correctly.
- Check if the water cooled chillers have full refrigerant charge by keeping a close eye on operating pressures and temperatures.
- For air conditioning chillers, clean the condenser coils and make sure that the condenser fans are working.
- For bigger chillers such as industrial or process chillers, performing an eddy current tube helps prevent major chiller breakdowns. This is a process wherein a trained technician runs electricity on each tube and studies the flow of current.

Following the above mentioned chiller maintenance tips help a great deal in preserving and lengthening the lifespan of your chillers.