GREEN Writeout 01 – Energy Saving Air Conditioning System
An Air Conditioning System (Aircon) “conditions” the air by purifying it as it absorb the air through a filter and releases cool and clean air. Air conditioner also lowers the humidity. Although air conditioner makes the air comfortable, it will also cause expensive electricity bills. Air conditioning can account for 5 to 50% of your household budget. Thus, it is important to select the “right” air conditioner to prevent heavy cost.
It is important to know your needs clearly before deciding whether to install a Central Air Conditioning System or Room Air Conditioning. Central Air Conditioning Systems are usually used for commercial buildings as they releases cool air though ducts located across the buildings. As for Room Air Conditioning, it has a smaller capacity which caters mostly to residential units or small offices.
Central air conditioners generally provide the greatest comfort but they also cost more than room units. If several rooms need to be cooled, however, a central system is probably the best buy. Central systems generally are not cost-effective as an addition to an existing home unless the existing ductwork can be used.
Room air conditioners are mounted in windows or built into an external wall. Room units are less expensive than central units; however, they only cool the general space in which they are located.
There are three types of room units;
-window models can be installed in most windows;
-casement window models, used in narrow, vertical windows, usually require the removal of a window panel for installation;
-and built-in models which are encased in a sleeve installed in the wall.
Size of air conditioner can be a factor to consider when purchasing it. This has to depend on the owners’ usage as well as capacity of the area to be cooled. For instance, an air conditioning unit which is bigger in size does not mean that it is good at cooling an area as it tends to cool the area faster if the capacity is small. This results in frequent on and off of the air conditioner which contributes to high electricity consumption and wastage. Vice versa, a small-sized air conditioning unit may not be sufficient to cool the area uniformly.
Therefore, it is advisable that owners consider the dimensions of the areas to be cooled and its purpose before deciding on the size of air conditioner to purchase.
Calculating BTU requirements becomes more complicated when you consider an area’s use. For instance, if you use passive cooling techniques such as shading, ventilation or vegetation, your BTU estimate can be lowered. Likewise, your BTU needs are increased by factors such as the size of the household, frequent use of heat-producing appliances, or summer humidity levels.
Energy efficient air conditioning units may be costly at the time of purchase, but its efficiency will lower its operation costs. It is definitely more worthy to spend more at first and save up throughout the years instead of spending less at first and continue to pay more for subsequent years. Maintenance costs also have to be considered upon purchase.
During installation of air conditioning units, it is mandatory to follow its detailed installation requirements in order to prevent energy wastage even for a high efficiency rated air conditioning unit. Air conditioners have to be installed in shaded area on the east or north sides of houses to reduce sunlight exposure. Room air conditioner should be installed on flat surfaces to ensure smooth operations for the inside drainage system and other mechanisms.
If your system is already exposed to the sun, a shading device such as an awning will protect the unit. Also, do not try to hide the unit’s external part behind shrubbery. The shrubbery reduces the unit’s ability to exhaust air and lowers its efficiency. Plenty of air circulation is mandatory.
Maintenance and Operation
Air filters has to be inspected once a month and cleaning is required if it is dusty. Clean filters help to reduce 5 to 15% of energy consumption. Drain channels should also be cleared to prevent blockage as excess moisture may damage walls and carpets.
Owners also need to conduct annual checks to make sure that seals in between air conditioning units and window frames are not damaged by moisture. Air conditioner coils should also be cleaned by vacuuming its interior heat exchanger. The exterior heat exchange may be cleaned using water.
For Central Air Conditioning System, ducts has to be properly insulated; specifically those which pass through unconditioned areas. Unoccupied rooms should also be shut to prevent unnecessary airflow.
Do not set the thermostat lower than the desired temperature when you first turn it on. It will not cool faster; it will only cool to a lower temperature than necessary and waste energy.
Set the fan speed on high except in very humid weather. When it’s humid, set the speed on low; you will get less cooling but more from the air which will make it feel cooler.
Curtains helps to keep out the heat in the day and windows could be opened at night to draw in cool air. Ventilation and vegetation also helps to reduce cooling needs. Although fans are unable to be as effective as air conditioner, it provides supplemental cooling and it saves 60% more in energy than air conditioner.
Air Conditioner and Mechanical Ventilation (ACMV) contribute heavily to energy usage in buildings. We can make it more energy efficient by having unitary air conditioner and implement Heat Pipe Technology to reduce air conditioning load. Building Integrated Heat and Moisture Exchange (BIHME) System and Variable Refrigerant Flow (VRF) with better specification and performance monitoring also help to make ACMV more cost efficient in the long run.
Air-conditioner heat recovery
Heat generated by outdoor unit could be used to power water heaters for energy savings.