To achieve maximum efficiency, an Air-Conditioning Evaporative Cooler Inspection should be performed regularly. One of the greatest benefits of air conditioning, besides allowing us to achieve the desired temperature in a room or home, is dehumidifying the circulating air. This benefit, however, is not without cost. In fact, cooling and dehumidifying the air is more costly than cooling alone.
In the southwestern part of the United States, the outdoor air is relatively dry, so dehumidification is not necessary. Consequently, cooling can be achieved by means of an evaporative cooler. If humidity is low, water evaporates, and in the evaporation process it absorbs heat from its surroundings and lowers the temperature.
A typical evaporative cooler consists of a sheet-metal and plastic casing containing a fan, filter, pads and a water source. The pads, which hold the water, can be wetted by a trickling stream, a spray or by passing through a reservoir on a rotating drum. There are also units in which the wetted pads function as air filters as well. As the air passes through the pads, it is cooled by the evaporating water and then distributed throughout the house.
Air-Conditioning Evaporative Cooler Inspection – Direct and Indirect Evaporative Coolers
During an air-conditioning evaporative coolers inspection, turn the unit on and listen for any unusual sounds or vibrations in the blower department. In addition, look for signs of water leaks and check the pads for deposits and crusting. The pads may require cleaning or replacement for in order to operate efficiently.
Evaporative coolers have a low cost at first, use far less electricity than conventional air conditioners and do not use refrigerants such as such as chlorofluorcarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) that can harm the ozone layer.
Basically, there are two types of evaporative coolers: direct and indirect. In a direct one, a blower forces the air through a permeable, water-soaked pad, and as the air passes through the pad it is filtered, cooled and humidified. An indirect evaporative cooler has a secondary heat exchanger which prevents humidity from being added to the airstream which enters the home.
Evaporative coolers can be used as a sole cooling system in a home, as an alternative cooling system to a refrigerant air conditioner or in combination with a refrigeration system. Conventional air conditioners, however, should not be operated simultaneously with direct evaporative coolers, because air conditioners dehumidify while evaporative coolers humidify, and the two systems will work in opposition.
The size of evaporative coolers is based on cubic feet per minute (cfm) of airflow. Typically, airflow for evaporative coolers is higher than conventional air conditioning systems. In hot desert climates, for instance, two or three cfm per square foot or three to four cfm per square foot is typical. Improperly sized evaporative coolers will waste water and energy and may cause excess humidity or other comfort problems.
Unlike air conditioned rooms, when an evaporative cooling system is operating windows or ceiling vents need to be open. The large volume of fresh air added to the home replaces a significant amount of air exiting from the house.
There are also many systems that incorporate a bleed-off valve that purges water about every six hours. This will result in an additional five gallons of water used per hour, however it may be necessary in some cases to reduce mineral buildup. Bleed-off valves are generally recommended.
Indirect evaporative coolers do not add humidity to the air, but they cost more and operate at a lower efficiency. Basically, they combine indirect with direct evaporative cooling by passing the air inside a heat exchanger that is cooled by evaporation on the outside. In the second stage, the pre-cooled air passes through a water-soaked pad and picks up humidity as it cools. The result is cool air with a relative humidity between 50 and 70 percent, depending on the regional climate.