Air Conditioning

Introduction:

Air-conditioning is the process of altering the properties of air (mainly temperature and humidity) to more favorable conditions, typically with the aim of distributing the conditioned air to an occupied space to improve thermal comfort and indoor air quality.

Generally, air-conditioning can refer to any form of technology that modifies the condition of air (heating, cooling, (de-)humidification, cleaning ventilation or air movement).

Evolution:

The concept of air-conditioning has been applied since Ancient Egypt. In Ancient Rome and medieval Persia some old techniques were used to cool buildings during the hot season.

The 2nd century Chinese inventor Ding Huan invented a rotary fan for air-conditioning with seven wheels.

After some scientist have done experiments related to the evaporation and cooling of some liquids, in the 19th century, the scientist and inventor Michael Faraday discovered that evaporating liquid ammonia it could chill the air.

John Gorrie created the first machine to make ice using compressor technology. With this machine he hoped regulated the temperature of buildings.

Evolution:

In 1842, Lord Kelvin invented the principles of air-conditioning. The aim was obtain a comfortable and healthy air. He created a cryogenic circuit based on the absorption of heat through a coolant gas.

In 1902, the first modern electrical air-conditioning unit was invented by Willis Carrier, in New York. This invention controlled the temperature and the humidity. He sent air through cold coils (filled with cold water). The air was cooled and thereby the moisture in the air could be controlled. Carrier’s technology was applied to increase productivity in the workplace. Over time, air-conditioning came to be used to improve comfort in homes an also automobiles.

In this photo we can see Willis Carrier next to the first air-conditioning unit.

How does an air-conditioner work?

Air conditioners use refrigeration to chill indoor air, taking advantage of a remarkable physical law: when a liquid converts to a gas (in a process called phase conversion), it absorbs heat. Air conditioner exploit this feature of phase conversion to evaporate and condense over and over again in a closed system of coils.

Air conditioners also contain fans that move warm interior air over these cold, refrigerant-filled coils.

For more information: http://home.howstuffworks.com/ac.htm

Link of a video that explains it:

https://www.youtube.com/watch?v=nKZ2DPvvua8

Parts of an air-conditioner:

Evaporator

Expanse valve

Compressor

Condenser

Types: Window air-conditioning system:

Window air conditioner are one of the most common used and cheapest type of air-conditioner.

This units are installed in an open window.

The interior air is cooled as a fan blows it over the evaporator. On the exterior the heat from the interior is dissipated into the environment as a second fan blows outside air over the condenser.

Indoors Outdoors

Types:

Ductless/ mini-split system:

This system supplies chilled air to a single or a few rooms of a building.

The compressor and the heat exchanger can be located further away from the inside space.

Ductless air conditioners can be very expensive.

Types:

Ducted/ central air conditioning:

This system offers whole- house or large-commercial-space cooling and also moderate multi-zone temperature control capability.

It is used in large buildings, theaters, hotels, shopping centers…

Types:

Portable units:

A portable unit can be easily transported inside a home or office.

They are evaporative or refrigerative.

Portable split units has indoor unit on wheels connected to an outdoor

unit via flexible pipes.

The future of air conditioning:

In the future, air-conditioner will use new types of coolants, compressor with less or even non-existent consumption. They are trying to design the most efficient systems that will supply a energetic savings.

Possible solutions would be the use of alternative energies, for instance the geothermal science, new solar air conditioners…

Using new technologies we would control our air conditioners, for example from our mobile phones or computers.

New technologies: Solar air-conditioing:

María Fernández Torres