What are ceiling fans and air conditioners and a cooler ?
Ceiling Fans :- Before air conditioners there were only air fans to achieve human comfort. These fans are simple combination of a motor and wings connected to it. When motor rotates the wings of fans creates movement of air in the room and it creates comfort for humans. When current passes through the coils of motor a magnetic field is created which tends to rotate the motor casing and electrical energy is converted to mechanical energy. Working principle is simple, hot air tends to move upward and cold air moves downwards and a ceiling fan simply rotates this motion. The air without change in temperature but at high velocity is directly thrown over the human body to feel comfortable. A fan is used only for rotation of air and it doesn't have any concerns with humidity control, temperature control, odours removal, air purification etc.
If there is no one in the room fan should be switched off.
Advantages :-
1. Low electricity consumption and low maintenance cost as only single motor converts the electical energy into mechanical energy.
2. No health issues.
3. Very low price as compared to AC.
Disadvantages :-
1. No temperature control, no humidity control, no air purification and no odour removal is done by a fan.
2. These fans are fail in monsoon or raining season as humidity level increases and it can not remove excess humidity.
Air Conditioners :- For human comfort we need air conditioning system. Air conditioning means not only to mainatain room's temperature but to condition the air as well. Means in air conditioning we maintain comfortable temperature, air purification, control humidity, control odours and maintain level of oxygen by ventilation. Air conditioners are designed to maintain a temprature not below than 16 degree celcius. But human comfort level according to ASHRAE is from 20-24 degree celcius. An air conditioner should not run at temperature below this limit to protect human body's health.
Air conditioning and refrigeration has same cycle and four components and same cycle to produce cooling effect. But main difference between them is, air conditioning is done for human comfort and refrigeration is done to increase the life of eatable products.
Let's understand how cooling effect is produced ?
There are four main components of refrigeration or air conditioner.
1. Compressor
2. Condenser
3. Expansion valve or capillary tube
4. Evaporator
Compressor is called heart of refrigeration cycle. Compressor has two ports one is for suction and other is for discharge. Compressor discharge the refrigerant to condenser (outdoor unit ) at a high pressure and high temperature. At this stage the refrigerant gas is in vapor form and when it starts to pass through the condenser it looses its temperature and comes in liquid form but pressure remains the same. After passing through the condenser refrigerant starts to pass through the expansion valve or capillary tube. Here is the hidden truth. This is the basic principle of gases that if gases are expanded in vaccum they loos temperature, same principle applies in air conditioning and Refrigeration. The expansion valve has very small dia through which refrigerant with high pressure tries to pass but because of tiny space it tends to loose its velocity and suction pressure of compressor start expanding this refrigerant due to which refrigerant's temperature goes down and cooling effect is produced. When this referigerant with low pressure and low temperature passes through the evaporator (indoor unit like split ac) it again gain the heat and space gets cool due to blower which is circulating room's air on its coils. If humidity level (moisture) is high in air, cooling and dehumidification process is performed by air conditioner. When room's air is circulated over the cooling coil of evaporator (indoor unit) humidity content starts to condense over the coils and start to flow through drain pipe in the form of water. This process in called cooling and dehumidification, so there is no separate humidifier installed in air conditioner.
Before filling the refrigerant with refrigerant vaccum inside the copper tube circuit is created so that expansion of refrigerant could take place.
This is how an air conditioner works.
Advantages :-
1. It controls temperatur, purifies air, controls humidity level and controls odours.
2. Air conditioners are very effective in rainy season as they work as a dehumidifier simultaneously.
3. Air conditioners are of various types and capacities according to the space size and heat load calcultions.
4. Applicable everywhere in automobile industry, in residential buildings and in commercial buildings as well.
Disadvantages :-
1. High initial cost as well as operating cost means electricity consumption is way too high as compared to a ceiling fan.
2. High maintenance cost.
3. Not good for human health if made to run beyond human comfort level.
4. Air conditioners are not good for environment as they are increasing global warming.
Advantages :-
- Power efficent, as compared to an air conditioner air coolers consumes low electrical energy and electricity bills are low.
- Eco-friendly, these units don’t produce any kind of global warming content.
- Very low cost as compared to any air conditioners.
- Can be easily installed and carry anywhere.
- No refrigerant gas is required separately to produce cooling effect.
- Very low maintenance cost.
- These coolers can be used where water is available easily in huge quantity.
- These coolers are useful only in dry season and in rainy season or monsoon they don’t perform well as the air is already humid.
- The water should be regularly changed so that no harmful bacteria could produce health issues.
- Pads needed to be changed after every season.