Air Washer: Overview, Parts, Working, Types, Advantages, Disadvantages, And Applications
The temperature inside the factories or warehouses exceeds 30 degrees Celsius in the hot summer. Employees feel uncomfortable working in much higher temperatures, and that decreases employee morale and productivity of the Company.
Conventional air conditioning can be the solution to this problem. But it involves a lot of installation and running costs.
Air washer is an excellent option to deal with this problem. Most of us know about the working of humidifiers and air purifiers. But the hybrid concept of air washer may leave you surprised.
Air washer is a device that suctions the polluted air and purifies it. It further cools the air, adds humidity, and then sends it to the desired space. You can even use an air washer at home to improve the air quality.
Parts Of Air Washer
Air washer is comprised of the following components
1. Insulated Water Tank
There is an insulated water tank on the bottom of the air washer. The water level is maintained constant in this tank. There is also a provision for make-up water.
2. Pump
The pump draws the water from the tank and sends it to the heater/Cooler. The water is either heated or cooled, and then it is an end to the spray nozzles inside the air washer.
3. Heater/Cooler
When the pump draws water at a specific pressure, it moves to the heater or cooler. The water is heated or cooled and then sent to the spray nozzles.
So by controlling the water temperature, you can achieve various psychometric processes like heating and humidification, cooling and humidification, and many more.
So the temperature leaving the air washer depends on the temperature of water sprayed inside the air washer.
3. Filter
When the polluted air passes through the filter, it removes all the dust, impurities, and allergens from it. As a result, clean air enters the air washer. It is cooled and sent to the conditioned space.
4. Blower
The blower draws the ambient air and admits it inside the air washer.
5. Spray Nozzles
The spray nozzles spray the water in mist inside the air washer.
6. Pipeline Arrangements
Pipeline arrangements are made so water from the insulated tank can rise and go to the spray nozzles inside the air washer.
Working Of Air Washer
The blower sucks the hot and polluted air, further entering the filter. The filter removes all the dust, impurities, and allergen and sends it inside the air washer.
The pump draws water from the tank and sends it to the heating or cooling arrangement. It then rises to the spray nozzles, which are fitted in the header pipe—the work of spray nozzles is to spray water in the form of mist.
So whenever the hot, dry, and unsaturated air passes through the air washer, it comes in contact with the water droplets sprayed by the nozzle.
The air washer works on the principle of evaporative cooling. The heat exchange will take place between the air and water. As a result, the temperature of the air gets reduced. Some mass of water vapor is even added to the air.
So finally, the cool and humidified air moves out of the air washer through the eliminator plates. It is then blown into the conditioned space. So here, we have achieved the cooling and humidification psychometric process.
You can use an air washer as a summer and winter air conditioning system just by changing the water temperature supplied inside the air washer.
Psychometric Processes Achieved By Air Washer
1. Cooling and dehumidification
Using an air washer, you can achieve a cooling and dehumidification process in the summer. But, the water temperature sprayed inside the air washer should be less than the dry bulb temperature of the incoming air but higher than the wet bulb temperature of the air.
When the air comes in contact with the sprayed water, sensible and latent heat transfer takes place, and finally, cooled and dehumidified air is released outside. You need to cool the water externally to achieve the process.
2. Heating And Humidification
You can achieve heating and humidification when you spray water inside the air washer at a temperature greater than the dry bulb temperature of the air inside the washer. Here you need to heat the water externally.
3. Adiabatic Saturation
You don’t need to heat or cool the water externally to achieve the process. You just need to recirculate the water in the air washer, as the sensible heat transfer equals the latent heat transfer. The water sprayed inside the air washer should have a temperature equal to the wet bulb temperature of the incoming air to achieve this process.
4. Cooling And Humidification
You can achieve a cooling and humidification process when the spray temperature is higher than the wet bulb temperature of the incoming air but lower than the dry bulb temperature.
5. Humidification
You can achieve a humidification process when the water sprayed inside the air washer is equal to the dry bulb temperature of the incoming air.
6. Cooling
You can achieve cooling when the water is cooled externally in the air washer. Here the water temperature sprayed inside the air washer should be equivalent to the dew point temperature of the incoming air.
Types Of Air Washers
An air washer is otherwise known as an evaporative cooler. It can be classified into two types based on the evaporative cooling system.
- Direct Air Washer
- Indirect Air washer
Direct Air Washer
In a direct air washer, the dry and unsaturated air passes through the air washer. The air comes in contact with water droplets, so sensible and latent heat transfer occurs.
As a result, cool and humidified air is released outside, which is further supplied to condition the space.
Indirect Air Washer
In an indirect air washer, the dry and unsaturated air is admitted inside the air washer. It comes with water droplets and heat transfers between air and water.
As a result, cool and humidified air is released. It is then passed into the fin and tube heat exchanger tubes. The secondary air(supply air to the conditioned space) is passed over the tubes. The sensible heat transfer takes place between the primary and secondary air, and as a result, the temperature of the secondary air reduces.
The secondary air is now cooled and will be supplied to the conditioned space. It is called an indirect air washer because the primary and secondary air doesn’t come in contact with each other. You get a better cooling effect through an indirect air washer than a direct air washer.
Advantages Of Air Washer
1. Cheaper
Air washers are cheaper than conventional refrigeration systems like air conditioners because a compressor, refrigerant, or condenser is not used.
2. Saves energy
Electrical energy is only used to run the blower and pump in the air washer. So it saves energy compared to conventional refrigeration systems.
3. Easy Maintenance
The parts used in the air washer are few and not expensive. So you can easily maintain them.
4. Provides Fresh air
Awasher always supplies 100 percent fresh air, so it will not create health problems.
5. Environment Friendly
There are no harmful chemicals used in the air washer. So they are 100 percent environmentally friendly.
Disadvantages Of Air Washer
.1. Moisture Level
There can be high moisture levels in the conditioned space.
2.No Control Of Temperature And Humidity
Using an air washer, you cannot control temperature and humidity in the conditioned space.
3. Can Create Heath Problems
If the water used in the air washer is not appropriately cleaned, microorganisms start developing inside. Breathing such air can create various health problems.
Application Of Air Washer
- Hotels
- Malls
- Industries like textile, printing, and package
- Pharmaceutical labs
- Office
- Manufacturing facilities
- Warehouses
- Factories
Conclusion
Air washer removes the dust, pollen, allergen, and other impurities from the air. It then cools and humidifies the air sent to the conditioned space.
The best thing about an air washer is that this device can achieve various psychometric processes like heating and humidification based on the sprayed water temperature.
We have discussed the air washer, its advantages, disadvantages, and applications, and we hope the information is helpful.
