What is Oil Fouling?

A Costly Energy Inefficiency Problem & Energy Saving Opportunity

Oil-fouling is everywhere and generates tremendous, steadily growing operational losses, not unlike corrosion. Losses due to the oil-fouling of heat-exchangers in industrialized nations are estimated to be about 0.25% of their GDP. These losses initially result from impaired heat-transfer, corrosion damage, increased pressure drop, flow blockages, flow redistribution inside components, flow instabilities, induced vibrations (possibly leading to other problems, e.g., system fatigue), premature failure of electrical heating elements, and a large number of other often unanticipated problems. In addition, ecological costs should be considered. Ecological costs arise from the increased fuel input to compensate for the reduced output caused by fouling. Installing Nano LiquiTec® enables systems to blow colder air faster, use less electricity, operate more quietly, require less maintenance, and live longer lives. It works as effectively in heat pump systems, creating a natural year-round demand.

A new class of breakthrough green technology, Nano LiquiTec®, with Graphene Dynamics® Technology, provides government and commercial customers, worldwide, a cost-effective, risk-free, guaranteed, proven, energy and carbon footprint saving solution for increasing energy efficiency in cooling, refrigeration, and heat pump systems of all sizes and in all climates by eliminating oil fouling.

The American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) states that some lubricating oil is lost from all compressors during normal operation. Since oil inevitably leaves the compressor with the discharge gas, systems using halocarbon refrigerants must return this oil at the same rate at which it leaves. ASHRAE states that unless oil is removed continuously from the point where it collects, it will cover the heat transfer surface in the evaporator, reducing performance.

As the oil and refrigerant mix, the chemical composition of both is drastically altered. The pressure and temperature characteristics of this refrigerant/oil mixture will be different from pure refrigerant. In addition, the viscosity of the oil is reduced by dilution with refrigerant, thereby increasing the probability of poor lubrication in the compressor. It matters little whether the refrigerant is miscible or immiscible with the oil. Contaminating oil films are deposited throughout the system, and it is these oil deposits that ultimately cause multiple problems.

The result of oil contamination is frequently noticed at the expansion device. Materials dissolved in the refrigerant-lubricant mixture, under liquid line conditions, may precipitate at the lower temperature in the expansion device, resulting in restricted or plugged capillary tubes or sticky expansion valves. A few milligrams of these contaminants can render a system completely inoperative. Any migrating oil in any refrigeration or air conditioning system is costly, both in kWh consumption and money and lost time spent on maintenance and repairs.

Effects on the System

Oil fouling of the heat transfer surfaces of air conditioning and refrigeration systems will cause a loss of efficiency that will continue to accumulate until equilibrium is reached between flow force and adhesion. At this point the oil boundary layer formed has achieved its maximum thickness, producing a maximum loss of efficiency. Published ASHRAE (Formerly the American Society of Heating, Refrigerating, and Air Conditioning Engineers), information confirms that performance is degraded by as much as 30% due to the build-up of lubricants on internal surfaces. Higher percentages of up to 40% have been observed in systems 20 years old or older.

The Definition of ASHRAE

ASHRAE, founded in 1894, is a building technology society with more than 50,000 members worldwide. The society and its members focus on building systems, energy efficiency, indoor air quality, refrigeration, and sustainability within the industry.

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