How Does a Refrigerant Recovery System Work?

Why Recover Refrigerants

Every home and business in the industrialized world has at least one machine that uses a refrigerant to heat or cool space, food or water. Hydroflourocarbon (HFC) gases make up the refrigerant chemicals that are compressed, circulated and re-compressed by refrigeration, air conditioning, heat pumps and other heat-exchange equipment. Most domestic refrigerants function for years without the need for replacement but some, including vehicle cooling systems and industrial units, must be changed on a fairly regular basis. The U.S. government began regulating the use of refrigerants with the Clean Air Act of 1990, which prohibited the use of older chloroflourocarbons (CFC) that were proven to dissipate ozone, raising concerns about effects on the atmosphere. The act gave the Environmental Protection Agency the responsibility of regulating the removal and recycling of these materials and contains standards and guidelines for their handling.

The Basics

Refrigerant recovery systems all work using a vacuum or compression pump, in a similar manner to the "donor" machines upon which they are used. Recovery machines contain one or more tanks connected to drain the refrigerant. Depending on the type of recovery apparatus, there may also be filters in this line before it enters the recovery tank. A vacuum pump pulls the refrigerant out of the donor's compressor and into the recovery tank. Current EPA standards require that 95 percent or more of the old refrigerant be evacuated from the donor. Recovery machines contain a "float cable" that signals the pump to shut off as the recovery tank becomes full; some have a "float chamber" that acts as an overflow tank. The chemical heats as it flows into the holding tank, much as it does in the compressor of the machine being serviced. Some recovery machines actually contain compressors rather than simple vacuum pumps that essentially enlarge the compression cycle to draw the refrigerant out into the recovery tank. Hoses used to drain systems are either 1/4 or 1/2 inch in diameter, depending on the specific refrigerant used. Technicians must match recovery equipment to the equipment to be serviced.

Options

Machines operated under high pressure (for fast draining) or long operation use cooling fans to keep the chemical from getting too hot in the transfer process. Recovery machines that also reclaim coolant may contain a number of filters and driers to remove pipe sealant or lubricant that may enter the coolant as it circulates in a donor system. Recovered refrigerant may also contain dye used by service technicians to test the system over the life of the coolant and moisture that gets trapped in the system when it is opened for draining or refilling. Once the refrigerant is recovered, some machines can actually complete the reclamation process using additional filters and tanks and recycle the refrigerant back into the donor machine.

Resources

• North American Retailer Dealers Association certification
• Ask a Mechanic--vehicle refrigerant recovery and recycling