26-10-2016, 12:23 PM
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Are you planning to buy a conventional type of air conditioner from the market? Wait a moment: the low cost, efficient, and eco-friendly homemade air conditioner design project shown here may just change your mind. The drawbacks of Freon and ammonia air conditioner units are also included.
• Spring doesn't stay long, and then it’s back to the sticky hot summer days. As summer heat becomes unbearable, air conditioners in every house become active and yet again the electric bills start soaring, disgustingly adding salt to the wound. And if your country happens to be within the tropical boundaries, this further makes the situation hostile.
Conventional air conditioners are efficient- there's no doubt about that- but they come with huge costs in the form of electric consumption and the associated utility bills. More electric usage from such units would mean that more hydro-electric and nuclear power plants will have to be installed in the future, resulting in the destruction and occupation of precious land and other natural resources in the process.
However, interestingly of late, scientists have started looking for many different renewable methods for replacing the above rather costly counterparts. Air conditioning is no exception and is at the core of their research.
Water as we know is the basis of life on this planet and moreover has unconditionally provided us with simple solutions to most of the energy related problems. Whether it’s a hydroelectric power station or a cheaply operated evaporative air conditioning unit, water forms the main and ubiquitous element everywhere - a magical fluid that’s available FREE of cost and plentifully on this planet.
Before moving into the proposed design of our homemade air conditioner, let’s study a few of the following conventional AC designs and their drawbacks
Probably one of the better ways of producing cooling effect in ACs, the procedure taking place inside a ammonia air conditioner can be understood with the following points:
Here ammonia acts as the chiller component whereas water acts as the absorbent.
From an ammonia water mixture, ammonia is forced out by heating the mixture in a gas-fired burner.
The separated ammonia is then passed through an outdoor coil and condensed.
The above condensed or the liquid ammonia is forced through another set of low pressure coils where it expands and evaporates to generate the required cooling after which it’s finally reabsorbed in water to repeat the cycle.
Drawbacks: Although ammonia is a highly degradable chemical agent and also does not affect the ozone layer in any way, it is definitely harmful to us in case it leaks out into our rooms. Therefore ACs using ammonia need to be positioned such that any leaking gas is kept well away from the room where it’s installed, quite a complicated and critical affair.
The running cost is also high, equal to the Freon ACs.
• Air Conditioner Based on Evaporation Principle
The important property of water of absorbing the ambient temperature while evaporating has been exploited to cool houses since the early ages. Even today the coolers based on evaporative technology use the above feature of water extensively.
The figure alongside shows the internal mechanism of a standard air cooler, also called a swamp cooler, based on the evaporative principle.
As we can see the entire process takes place inside a rather large box type enclosure.
The side walls of the enclosure have slotted ventilations for the surrounding warm air to get in.
A layer of thick spongy pad is placed immediately after the side ventilations inside the box.
A small electric water pump is used to transfer water from the bottom reservoir over these pads from the top so that they are properly soaked. The excess water drips down back into the reservoir.
A motor/pulley mechanism is used to rotate the propeller of a large fan at the front of the box. When it starts moving, the surrounding air is sucked inside the box through the side ventilations.
The air is dragged in through the water soaked pads where due to evaporation the sucked air loses its temperature and becomes cool.
The cooled air is ultimately forced out by the fan outside into the room, for the desired cooling.
The above principle may be enforced or implemented through different ways and may also be enhanced through new innovations.
For example, water sprinklers are used over the roofs of many houses where the water droplets evaporate helping the house to lower their internal temperature. The principle has been thoroughly studied and improved by NREL and they have succeeded in building a super efficient air conditioner entirely based on evaporative technology.
Although quite cheaper than an ammonia air conditioner, a swamp cooler may be accompanied with certain drawbacks. Here, the evaporated water molecules are distributed into the premise, unnecessarily increasing the relative humidity of the room. This can become a big nuisance especially for the coastal countries where the RH remains already on the higher side for most months. Also the efficiency of these units drastically fall as the surrounding humidity increases.
In our present design of homemade air conditioner, we rather take a different approach and use cold water to produce the required cooling effect, but not in a evaporative manner. This is a bit costly than the swamp coolers, but surely way ahead as far as the efficiency is concerned.