Why Your Chiller Loses Efficiency

From Day one HVAC systems, including commercial grade air conditioning, chiller and refrigeration unit begins losing energy efficiency due to the effects of oil fouling. Typical oil fouling, which is the accumulation of unwanted deposits in the coil system of your HVAC unit can lead to an energy efficiency loss of up to 30% in the early stages of the units life. This happens through no fault of your own, it has nothing to do with how much you invested in your system, the brand you have or how often you have it serviced.

ASHRAE, the international technical society organized to advance the arts and science of H.V.A.C. (Heating, Ventilation, Air Conditioning & Refrigeration) have confirmed, after decades of studies, that the typical will lose about 7% of its energy efficiency within the first years of operation, 5% the second year and a further 2% per year thereafter, up to a total of about 30%.

These efficiency losses are due to the effects of oil fouling which occurs from the very first moment of your systems operation. Oil fouling is the accumulation of unwanted oil deposits in the coil system of all HVAC units (that utilize a refrigerant lubricating oil), regardless of refrigerant type and or whether the unit is a flooded on non-flooded type.

During the refrigeration compression process that takes place within a system, the units very own lubricating oil migrates from the air conditioning motor/compressor to the coil system of the condenser and evaporator contaminating the metals that transfer heat. Even by having oil separator’s and filters in place, still small quantities of oil migrate. Lubricating oil is NON-CONDUCTIVE (Conductivity rate of standard refrigerant oil is 0.94). This layer of non-conductive material creates a Laminar Friction causing the refrigerant to travel like a bullet with a sharp point which drives up energy use, increases wear and tear, shortens the life of your system and reduces your systems ability to produce quick and efficient comfort.


Please note, for the purposes of explanation, the above graphics is demonstrating the effects within the heat exchanger tubes, in the event you have a flooded system, the below effect is the same except that it occurs outside the tubes within the sealed vessel.