Most air conditioning and refrigeration systems have a mechanical
compressor which relies upon lubricating oil to function. During the
normal course of the refrigeration process, ˝% to 8% of the
compressor’s lubricating oil is circulated throughout the system
along with the refrigerant. Since the early days of refrigeration
and air conditioning technology, the American Society of Heating,
Refrigeration and Air-Conditioning Engineers (ASHRAE) have addressed
the results of this oil fouling1.
This oil fouling arises because the compressor oil builds up on the
metallic walls of the refrigeration tubing reducing the heat
transfer from the refrigerant to the walls of the refrigerant
2. Effects on Heat Transfer
Oil fouling of the heat transfer surfaces of air conditioning and
refrigeration systems will cause a loss of efficiency of the air
conditioning or refrigeration system. This loss is about 7% after
the first year, another 5% after the second year, and a further 2%
per year the following years2.
This loss will continue to accumulate until equilibrium is reached
between flow force and adhesion (surface tension). At this point the
oil boundary layer formed has achieved its maximum thickness,
producing maximum loss of efficiency. Usually, the efficiency
degradation will peak somewhere between 20% and 30%. Published
information by ASHRAE confirms these observations: performance is
degraded by as much as 30% due to the build-up of lubricants on
internal surfaces3. Higher percentages
up to 40% have been observed in systems 20 years old or older.
The losses in efficiency are independent of the type of system.
These physical principles apply equally to air conditioning units in
automobiles, through the wall room coolers, domestic split systems,
walk in refrigerators and freezers, commercial and industrial split
and duct systems, and chillers (both air cooled and water cooled).
3. Effects on the System
Any migrating oil in any refrigeration or air conditioning system
is costly, in power consumption, money, and lost time spent on
Maintenance and repairs.
Equipment suppliers may state that in a particular system, migrating
oil concentration has been reduced to only one percent. The one
percent being referred to is one percent of the total oil volume. If
a compressor has 128 fluid ounces (3.8 litre) of oil, then at one
percent, 1.28 ounces (38 ml) is flowing through the system at any
given time. Since a capillary tube, oil pressure switch, or
expansion valve and the entire length of heat exchanger tubing can
be fouled with a few milligrams of oil, when one percent of any oil
charge is flowing constantly through the system, the system will
become fouled with oil.
4. Managing the Problem
The oil that finds its way into the system must somehow be
managed4. The question then becomes how
to manage this troublesome oil. Some of the techniques used by
manufacturers to control migrating oil include the use of mechanical
devices such as separators, skimmers, drums, heat sources, suction
risers, traps, and pumps. According to ASHRAE’s Handbook, these
high-tech designs are not efficient enough to prevent the oil from
travelling through the system and subsequently sticking to the
inside of the tubes. Most of this oil can be removed from the stream
by an oil separator and returned to the compressor. Coalescing
separators are far better than separators using only mist pads or
baffles; however, even they are not 100% effective. Although the
mechanical solutions may reduce the problems of restricted or
plugged capillary tubes or sticky expansion valves, they do not
resolve the boundary layer fouling over time.
5. The Solution
The thermal transfer efficiency loss can be resolved by a
Monopolar Magnetic Field Generators (MMFG's) that defeat and
release the surface tension forces. It is this van der Waals force
that causes the compressor oil globules to adhere to each other and
then to refrigerant tubing walls, forming the oil fouling5.
Such an additive can defeat the surface tension by tightly bonding
to the metal surfaces in a layer that is one molecule thick and
thereby prevent the recurrence of oil contamination on the heat
transfer surfaces. The release of the oil contamination restores the
lost 20% to 30% thermal transfer efficiency. An added benefit is
that the capillary tubes and expansion valves are also cleaned and
protected from future fouling.
The Engineered Magnetic Field Generators are compatible with all
refrigerants and oils in common use in domestic, transportation,
commercial, and industrial systems.
6. Financial Benefits
Mechanical devices which can ease oil fouling typically yield
improvements in energy efficiency by 2% to 5%, with a return on
investment (ROI) of three to ten years. MMFG's that can defeat the
surface tension of the oil can provide an energy efficiency
improvement of 15% to 25%. Depending on electricity costs and usage,
this typically yields a simple ROI of under a year
An additional benefit is that because the system is operating with
less stress it will require less annual Maintenance charges (AMCs).
Although this is hard to quantify, the reduction in these charges
can be expected to be also 15% to 25%.
The usage of our Engineered Magnetic Field Generators presents a
radical shift from the view that established methods of working are
always correct. The new technology is gaining acceptance due to the
information published by ASHRAE and numerous authenticated case
See links below for more info on MMFG solution
1 ASHRAE Handbook, Refrigeration, Chapter 3.6.
ASHRAE Handbook, Refrigeration, Chapter 2.9.
3. A Survey of Refrigerant Heat Transfer and
Pressure Drop Emphasizing Oil Effects and In-Tube Augmentation;”
ASHRAE Winter Symposium of 1987; Schlager, Pate, and Bergles.
4. ASHRAE Handbook, Refrigeration, Chapter
5. The powerful surface tension forces – van der Waals force – are
10^39 times stronger that gravity.
Magnetizer Refrigerant Patents
Non-Chemical Magnetics - Federal Technology Alerts Article
A1 Green Energies -
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