How an Aquarium Chiller Works

Most aquarium chillers use a vapor-compression method to chill your aquarium water. While the science behind this process can be a little complicated, it is a good idea to understand the basic principles and components in order to properly operate and maintain the chiller.

Chiller 1

The diagram above represents the basic parts found on common aquarium chillers and we've outlined the functions below in order to help you better understand exactly how your aquarium chiller works.

  1. Aquarium water is pumped into the chiller and enters the heat exchange. Inside the heat exchange, aquarium water flows around a series of cool metal coils filled with refrigerant. This is where heat is transferred from your aquarium water into the refrigerant.
  2. Heated refrigerant is compressed and changes from a liquid into a gas inside the compressor. The pressure created inside the compressor is what moves the refrigerant through the cooling system.
  3. Gaseous refrigerant is sent into the condenser from the compressor via pressure. A fan blows air over the condenser cooling the refrigerant inside and expelling heat into the atmosphere around the chiller. This is why it is important to place your chiller in a well-ventilated area. This process is similar to what happens in the radiator in your car.
  4. As the refrigerant passes through the condenser, it is cooled and transformed back into a liquid.
  5. Refrigerant from the condenser passes through an expansion valve which reduces pressure inside the refrigerant line controlling the rate at which the aquarium water is cooled inside the evaporator or heat exchange.
  6. A temperature controller monitors the temperature of your aquarium water and automatically switches the chiller ON when the temperature rises and turns it OFF when temperatures are within a suitable range. The temperature controller is built into most chillers, but sometimes sold separately depending on the brand of the chiller.

Quick Tips

  • Choose a water pump that can provide the proper flow rate through your chiller.
  • Always place your chiller in a well-ventilated area.
  • Never let your chiller run dry; this can quickly damage internal components.
  • Chillers use a substantial amount of power; be sure to allow for the necessary electricity consumption in addition to all of the other equipment on your aquarium.
  • Clean the fan and condenser fins regularly to remove dust and increase air flow.
  • Calcium build up inside the heat exchange can reduce chilling efficiency; regular back-flushing with a freshwater/vinegar solution can help remove build-up and keep your chiller performing optimally.
  • A properly sized chiller is important for longevity and proper function. Your chiller should only be ON for roughly 15-20 minutes per hour.