Air coolers are a cheaper option than air conditioner. They work well in dry areas, in humid climates they are not effective and hence can be avoided.
Air coolers need a lot of water to be filled, hence this can be a big disadvantage if you do not get enough water in summers.
WHAT IS AIR COOLER?
Air cooler works simply where water is put in the cooler. The air is circulated by the pump in the cooler as water is sprinkled on the pads of the cooler. This evaporates the heat and cool air is circulated in the room. You can check more about air coolers at http://www.symphonylimited.com/pdf/Evaporative-brochure.pdf
TYPES OF AIR COOLERS
Direct, Indirect and two-stage evaporative cooling
Direct evaporative coolers are the most common, used to lower the temperature of air by using latent heat of evaporation, changing water to vapor.
Indirect evaporative cooling uses some form of heat exchanger. The moist cooled air does not come in touch with the environment outside.
Two stage cooling goes through 2 stages. In the first stage the air is precooled by heat exchanger. The precooled air in second stage through water soaked pads. Since precooled air goes through in the second stage, in this type of cooler the humidity will be less.
Difference between desert coolers and room coolers
Desert cooler is better and provides better cooling.
However desert cooler requires more power, more space and more water. In a hot place this type of cooler should be preferred.
In a smaller room and less hot environment, room coolers should suffice.
COMPARISON OF AIR COOLERS AND AIR CONDITIONERS
Air coolers use less energy than an AC.
Air coolers need less maintenance than an AC. Also does not need elaborate installation and hence this cost is almost negligeble unless you have some special requirements.
Air coolers have environmental benefits with no harmful Chlorofluorocarbons (CFC) or gases emissions and very low power consumption.
Air conditioners are more effective in extreme temperatures and also in humid environments.
Air conditioners can control temperature which an air cooler cannot do.
Air coolers increase humidity which reduces evaporative functions of human organs.
Air coolers require regular supply of water to wet the pads. In areas where water supply is not constant, this may not be a feasible option
CHOOSING AIR COOLER SIZE
Air coolers are rated by air delivery or the cubic feet per minute of air that the cooler can blow into your home. You can use simple formula to identify the proper size of air cooler that you need.
(SQUARE FEET AREA X CEILING HEIGHT) / 2 = CFM OF AIRFLOW NEEDED.
So if you have a room of 500 sq feet with ceilings of 8 feet high then
( 500 X 8 / 2 ) = 2000
Hence, you will need a cooler with minimum air flow of 2000 cfm.
All air coolers will clearly define the air delivery.
AIR COOLER FEATURES
Cooling media today is mostly honeycomb nowadays. It is made from specifically engineered cellulose paper that is chemically treated to resist deterioration.
Honeycomb cooling pads are designed to provide maximum cooling, low pressure drop and longevity.
Thickness of Pads/media
Pad thickness is essential to get air cooled well - pads should generally be at least 90 mm thick.
Variable speed coolers are used to control the speed of the fan. Unlike 2 speed coolers in the past now the coolers give multiple speed options which can be controlled via regulator or remote, this help specially at night if the environment becomes cold
Electronic thermostats can vary the fan speed automatically, and switch the pump and fan on and off.
Automatic Shutoff Dampers
There are periods when the cooler does not run specially when the summer ends. This necessitates covering the cooler.
The shutoff dampeners are flaps in discharge of fan or in duct which opens when fan starts and closes when the fan is put off. This reduces the loss of cooling from the cooler.
Automatic Water Level Controller
Air coolers come with automatic water level controllers which can maintain water in the cooler at preset levels. This prevents flooding.
A water inlet pipe is needed for this. The controllers automatically lets or prevents water from the connection to flow into the tank.
Water Level Indicator
The water level indicator is useful to determine how much water is there in the water tank. This is an essential feature as otherwise you need to check on the water tank by opening the cooler. Whenever the indicator shows water levels as low you can fill the water tank.
Castors are wheels provided at the bottom of the air cooler so that it can be moved freely whenever needed.
Air coolers nowadays come with remote control for easy and convenient mode of operation. Setting up speed control is one of the important features which can be controlled by remote control.
Air Coolers from local manufacturers will be cheaper compared to branded players. The benefit of branded air coolers is that you will not need to haggle over individual parts though there is a premium to these coolers. The branded ones will come with warranty and additional features which the local ones might not offer.