The best methods for recycling refrigerant require an explanation of what refrigerant is and its role in the cooling cycle of refrigerators, freezers, air conditioners and other appliances. Refrigerants are compounds used in cooling that are boiled from liquid to gas then condensed back to liquid. In the 1980s, many of those compounds were discovered to be major contributors to ozone depletion. 

Since the Montreal Protocol (1987), countries all over the world are agreeing to phase out toxic refrigerants and other hydrochlorofluorocarbons (HCFCs) with natural, environmentally friendly compounds.

Refrigerant's power to deplete the ozone and contribute to global warming decreases when proper methods for recycling are followed. One of the best methods for recycling refrigerant starts with installation. HVAC technicians must ensure that home systems that use refrigerant are installed properly. This prevents HCFCs and chlorofluorocarbons (CFCs) from leaking into the atmosphere in the first place.

Portable air conditioning units are similar to window units, but they can be moved around from room to room. They are generally used to cool small spaces such as a small bedroom or office. Portable air conditioning units are often used to supplement a central air conditioning system, in situations where a little extra cooling may be needed. This might include a computer server room, where the computers give off a lot of heat but must be kept fairly cool to operate properly. Portable air conditioning units also work well in small meeting rooms crowded with people, or helping to cool that one bedroom in your house that's always too warm even when the rest of the house is comfortable.

A portable air conditioning unit works in much the same way as a standard window unit. It has a compressor and uses a gas, normally freon, to remove the heat from the air. This hot air must be vented through an exhaust hose, which is routed out a window or into an adjoining space such as the attic, or into the space between the walls. Portable air conditioning units also collect condensation from the air that is cooled, so most units have a water reservoir that must be emptied from time to time.

A mechanical refrigeration system cools by circulating a fluid through a sealed circuit of pipes or tubing. The fluid absorbs heat in the space to be cooled and carries it away to where it is less objectionable. The entire cycle relies on just a few components and laws of physics to reduce the temperature of an area.

The mechanical aspect of the cycle starts with a compressor, a combination electric motor and pump. In the compressor, a low pressure, gaseous refrigerant is squeezed down to a greatly reduced volume. This compression raises the refrigerant’s temperature and pressure and pushes it into the next component, the condenser. The condenser is merely a coil of tubing over which air can flow. In the condenser, the high pressure/high temperature gas releases its heat and becomes a liquid.

A digital thermostat can control the heater and air conditioning (AC) unit in a building, replacing standard analog heater thermostats present in older homes. Among the advantages of switching out the old unit for a new digital model are convenience and savings in the form of a lower energy bill.

Standard thermostats are commonly mounted on a wall in a convenient location where they monitor the room’s air temperature. They are set by adjusting a pointer over a specific temperature along a dial. The thermostat will only trigger the heater on if the temperature in the room falls below the setting. Once the heater comes on, it will stay on until the room warms back up to the setting. At that point, the thermostat turns the heater off.

It’s quite easy to replace an analog thermostat with a new digital model. The old unit is typically held to its mount by one or two screws. Before uninstalling it, switch off power to the unit at the main circuit breaker panel. After removing the screws, wiring coming through the wall to the unit will need to be disconnected and reconnected to the new digital thermostat. The number of wires will vary depending on attached equipment. Be sure to follow all instructions carefully, connecting the correct leads to the correct posts, including the ground wire.

An air conditioning specialist installs, maintains, and repairs heating, air conditioning, and refrigeration systems and may work in commercial or residential settings. These specialists are sometimes referred to as heating/ventilation/air conditioning repair (HVACR) technicians or air conditioning technicians. 

An air conditioning specialist may acquire training from on-the-job experience, an apprenticeship, or through a formal training program. Diagnosing problems, maximizing overall operational efficiency, conducting equipment inspections, and determining fuel or energy consumption is an important part of this job. In order to effect repairs, service contracts and conduct maintenance on various systems, an air conditioning specialist needs to possess some specialized skills and certifications.

Ongoing training to keep up with the ever-changing technology associated with modern air conditioning, heating and ventilation systems is essential for an air conditioning specialist. Some state and regional authorities require licensure, which involve learning the latest information and passing a written test, for air conditioning specialists. 

Some specialists have acquired additional certifications that indicate various levels of competence in handling specialized equipment. For example, special certifications is required for handling anything that uses natural gas or a high pressure boiler. An air conditioning specialist may also be required to pass an examination and gain certification to learn the proper handling of refrigerants.