HVAC (Heating Ventilation and Air Conditioning)

HVAC (Heating Ventilation and Air Conditioning)

Air conditioning, or HVAC&R, is an active, rapidly developing technology. It is closely related to the living standard of the people and to the outdoor environment, such as through ozone depletion and global warming. The term HVAC&R is an abbreviation of heating, ventilating, air conditioning, and refrigerating. The combination of processes in this commonly adopted term is equivalent to the current definition of air conditioning. Because all these individual component processes were developed prior to the more complete concept of air conditioning, the term HVAC&R is often used by the industry.

HVAC&R, system is composed of components and equipment arranged in sequence to condition the air, to transport it to the conditioned space, and to control the indoor environmental parameters of a specific space within required limits. Most air conditioning systems perform the following functions:

l  Provide the cooling and heating energy required

l  Condition the supply air, that is, heat or cool, humidify or dehumidify, clean and purify, and attenuate any objectionable noise produced by the HVAC&R equipment

l  Distribute the conditioned air, containing sufficient outdoor air, to the conditioned space

l  Control and maintain the indoor environmental parameters–such as temperature, humidity, cleanliness, air movement, sound level, and pressure differential between the conditioned space and surroundings—within predetermined limits.

Parameters such as the size and the occupancy of the conditioned space, the indoor environmental parameters to be controlled, the quality and the effectiveness of control, and the cost involved determine the various types and arrangements of components used to provide appropriate characteristics. Air conditioning systems can be classified according to their applications as (1) comfort air conditioning systems and (2) process air conditioning systems.

Comfort air conditioning systems provide occupants with a comfortable and healthy indoor environment in which to carry out their activities. The various sectors of the economy using comfort air conditioning systems includes the commercial sectors (office buildings, supermarkets, shopping centers etc.), institutional sectors (colleges, concert halls, theaters etc.), residential sectors ( hotels, motels, apartment houses etc.), health care sectors ( hospitals, nursing homes, and convalescent care facilities), and transportation sectors ( aircraft, automobiles, cruising ships etc.)

Process air conditioning systems provide needed indoor environmental control for manufacturing, product storage, or other research and development processes. Some example of areas that require process air conditioning systems are, humidity control in textile mills, clean room for electronic product manufacturing, precise temperature control during the production of precision instruments, and temperature, humidity and air cleanliness control for pharmaceutical products.

Reference:

Shan K Wang, Handbook of Air Conditioning and Refrigeration, McGraw-Hill, 2001.