We regularly get asked about the water consumption of our units. The exact amount is actually very hard to determine as usage depends on the following variable factors.
Setpoint temperature: One of these factors is the setpoint temperature of the room that is being air conditioned. This is because more water will be required to bring the room down to say, 18deg C than it would if it was set to our recommendation of 22 - 23degC.
Outdoor air temperature: The outdoor air temperature is also going to play an important role in the amount of water consumption. The hotter it is outside the more heat is being transferred from the outdoor air to the cooler room being air conditioned.
Building Materials: Another factor is how your property has been constructed and the type of materials that have been used. A building with a lot of glass and thermal insulation will absorb external heat and retain it in the building for longer.
Input water temperature: As we are using cold water to cool the hot refrigerant, the colder the water that comes into the system, the less that will be required to remove the latent heat from the refrigerant.
Usage: Probably the most obvious is the number of hours the unit is operating for someone who leaves the air conditioning system on all day will require a lot more water than someone that switches the system on for a few hours to cool a bedroom before going to bed.
To give you an idea - an average sized bedroom of, 5m x 4m, with a normal amount of glass windows, well insulated to modern building regs, an outdoor temperature of 27degrees C and an incoming water supply of 12degC - would require a 2kw indoor unit, as well as the condenser unit. This condenser would give out a water flow of 40 litres per hour to cool the room to 22 degrees.
Our condenser units only use water when the condenser is running to provide cooling. When the room has reached the setpoint temperature of 22 - 23 degC the condenser will switch off. To maintain the setpoint temperature of the room or systems normally only take 20 – 30 minutes per hour of operation, so water consumption will drop when the setpoint temperature is simply being maintained.