1) Can you describe to us why the efficiency decreases in AC/R and vehicle A/C systems?

A normal decrease in the system – when no refrigerants leaks occur – is usually linked to a reduction in heat exchange between the refrigerant gas and the exchangers of the system itself.

2) What is the reason for the heat exchange reduction?

It is well known that, inside an AC/R system, together with the refrigerant gas, there are also fractions of compressor oil lubricant (from 1 to 8%) which tend to deposit on internal walls of the evaporator and condenser pipes. This process is called Oil Fouling: it’s harmless for a new system, as the lubricant – that leaves the compressor – returns to it at the end of the cycle. However, over time, less soluble and heavier fractions of the lubricant tend to settle, often in the exchanger and valves. These deposits reduce the space for the refrigerant gas flow and the metal surface where the heat exchange takes place. Heavier fractions, which do not return to the compressor, reduce the lubricating capacity of the oil remaining in the compressor. Besides, moisture from the system collects in these oil deposits, which triggers acidification and oxidation processes.

3) Can we consider Oil Fouling a natural process or an unusual one?

It’s a normal phenomenon that must be kept under control with proper maintenance and the use of a specific additive.

4) What are the consequences of Oil Fouling in an AC/R system?

In an AC/R system, Oil Fouling reduces the heat exchange between the refrigerant gas and the pipes, decreasing the diameter of the latter. Furthermore, this process weakens the lubricating capacity of the oil and the volume of lubricant in the compressor. According to ASHRAE data, this results in a reduction in system efficiency of about 30%.

5) What are the consequences of Oil Fouling occurring in vehicle A/C system?

In a vehicle A/C system the Oil Fouling process causes the same consequences as in residential and industrial AC/R systems.

6) How do I know if the efficiency of an AC/R and vehicle A/C system has decreased?

The efficiency decrease is easily observed by measuring the temperature of the air leaving the evaporator. If the system – set at the minimum temperature – is not as efficient as when you bought it, it means that it isn’t working at its best and action must be taken. Moreover, the system tends to be noisier and consume more energy.

7) How can the problem be solved?

The system can be properly cleaned and replace the lubricant: but these are long and expensive operations for the owner. Alternatively, an additive can be added to dissolve the deposits, allowing the lubricant to run off towards the compressor and inhibiting new deposits.

8) Which product do you suggest using and why?

I absolutely recommend Cool-Shot Ultra: a synthetic catalyst able to maintain or restore the efficiency of all AC/R systems.
It’s the ideal product for several reasons: first of all, it restores the heat exchange of the system by removing all the deposits of lubricant accumulated over time or avoiding their formation if inserted in new systems.
Secondly, it extends the life of the compressor and reduces friction inside it, bringing down vibrations and noise. The result is a reduction in system maintenance costs and CO2 emissions.
Furthermore, Cool-Shot Ultra is safe for the system: it doesn’t cause chemical changes to the lubricant, it doesn’t alter the refrigerant gas, it doesn’t contain polymers and it doesn’t react with humidity and oxygen.
Finally, it’s compatible with all refrigerants including CO2, except R717 (ammonia), and it’s suitable for all types of air conditioning and refrigeration systems (AC/R and vehicle A/C).

9) Without placing the additive in the system, is it possible to prevent the formation of Oil Fouling? If so, how?

No, it isn’t possible to avoid the formation of Oil Fouling deposits, but it can be optimised by carefully evaluating the selection of the lubricant for the refrigerant gas chosen.

10) Do you have any advice for our readers?

Certainly. I recommend adding Cool-Shot Ultra. This additive hasn’t any contraindications when used in any type of AC/R system. In older systems you can easily notice an improvement in their performance and a significant reduction in electricity consumption. In new systems – used for preventive action – Cool-Shot ultra will avoid the natural decrease in efficiency over time.