Air Conditioning and Refrigeration

1. Cold storage The cold storage is a building designed to store certain goods like food stuffs, fruits, vegetables and dairy product within well defined temperature range and relative humidity. The temperature and humidity condition maintained inside a cold storage depend upon the type of product stored inside. Vegetables require the maintenance temperature of around […]

Cooling towers overcome most of these problems and therefore are commonly used to dissipate heat from water-cooled refrigeration, air-conditioning, and industrial process systems. The water consumption rate of a cooling tower system is only about 5% of that of a once-through system, making it the least expensive system to operate with purchased water supplies. Additionally,

Concept of Psychrometry and Psychrometrics Air comprises of fixed gases principally, nitrogen and oxygen with an admixture of water vapour in varying amounts. In atmospheric air water is always present and its relative weight averages less than 1% of the weight of atmospheric air in temperate climates and less than 3% by weight under the

In vapour absorption system the refrigerant is absorbed on leaving the evaporator, the absorbing medium being a solid or liquid. In order that the sequence of events should be continuous it is necessary for the refrigerant to be separated from the absorbent and subsequently condensed before being returned to the evaporator. The separation is accomplished

SIMPLE VAPOUR COMPRESSION SYSTEM Out of all refrigeration systems, the vapour compression system is the most important system from the view point of commercial and domestic utility. It is the most practical form of refrigeration. In this system the working fluid is a vapour. It readily evaporates and condenses or changes alternately between the vapour

Refrigeration Literal meaning of refrigeration is the production of cold confinement relative to its surroundings. In this, temperature of the space under consideration is maintained at a temperature lower than the surrounding atmosphere. To achieve this, the mechanical device extracts heat from the space that has to be maintained at a lower temperature and rejects

Comfort chart The Comfort Chart is a tool that helps operators determines how well air-handling equipment is providing thermal comfort for the building occupants or for a process within the facility. In designing winter or summer air conditioning system, the designer should be well conversant with a number of factors which physiologically affect human comfort.

Humidification and Dehumidification The addition of moisture to the air without change in its DBT is known as humidification and removal of moisture from the air without change in its DBT is called as dehumidification.   Sensible heat factor: It is the ratio of sensible heat to total heat. SHF= Cooling and Dehumidification When moist

The basic functions of an expansion device used in refrigeration systems are to: Reduce pressure from condenser pressure to evaporator pressure, Regulate the refrigerant flow from the high-pressure liquid line into the evaporator at a rate equal to the evaporation rate in the evaporator It controls the flow of refrigerant according to the flow of

The evaporator works the opposite of the condenser, here refrigerant liquid is converted to gas, absorbing heat from the air in the compartment. This causes the refrigerant to absorb heat from the warm air and reach its low boiling point rapidly. The refrigerant then vaporizes, absorbing the maximum amount of heat. While the refrigerant is

Condensers and evaporators are basically heat exchangers in which the refrigerant undergoes a phase change. In condensers the refrigerant vapour condenses by rejecting heat to an external fluid, which acts as a heat sink. In a typical refrigerant condenser, the refrigerant enters the condenser in a superheated state. It is first de-superheated and then condensed

The compressor is the main moving component of the vapour-compression system. It provides the system with the force to draw the vapour from the evaporator, to force it into the condenser by creating a high pressure and to maintain circulation of the refrigerant. The compressor’s work begins by its creating a low-pressure region on the

Air conditioning is the process of removing heat and moisture from the interior of an occupied space to improve the comfort of occupants. Air conditioning can be used in both domestic and commercial environments. This process is most commonly used to achieve a more comfortable interior environment, typically for humans Factors affecting comfort air conditioning:

The refrigerant is a heat carrying medium which during the cycle in the refrigeration system absorbs heat from a low temperature system and rejects the heat to a higher temperature system. Refrigerant Classification Refrigerants are working substances or heat- carrying medium in refrigeration system, during a refrigeration cycle heat is absorbed from a low temperature

A vapour compression refrigeration system is an improved type of air refrigeration system in which a suitable working substance, termed as refrigerant, is used. It condenses and evaporates at temperatures and pressures close to the atmospheric conditions. The refrigerants, usually, used for this purpose are ammonia (NH3), carbon dioxide (CO2) and sulphur dioxide (SO2). The refrigerant used, does. not leave

In an air refrigeration cycle, the air is used as a refrigerant. The basic elements of an air cycle refrigeration system are the compressor, the cooler or heat exchanger, the expander and the refrigerator. Units of Refrigeration The practical unit of refrigeration is One tonne (1000 kg )of ice from and 00 in 24 hours. expressed

AIR CONDITIONING SYSTEMS  Introduction: In order to maintain required conditions inside the conditioned space, energy has to be either supplied or extracted from the conditioned space. The energy in the form of sensible as well as latent heat has to be supplied to the space in winter and extracted from the conditioned space in case

PSYCHROMETRIC PROPERTIES The properties of moist air are called psychrometric properties and the subject which deals with the behaviour of moist air is known as psychrometry. Moist air is a mixture of dry air and water vapour. They form a binary mixture. A mixture of two substances requires three properties to completely define its thermodynamic

VAPOUR ABSORPTION SYSTEM The vapour absorption refrigeration is heat operated system. It is quite similar to the vapour compression system. VAPOUR COMPRESSION SYSTEMS The challenge in refrigeration and air conditioning is to remove heat from a low temperature source and dump it at a higher temperature sink. Compression refrigeration cycles in general take advantage of

REFRIGERATION COMPONENTS Refrigeration system consists of several equipment like compressor, condenser, evaporator, expansion devices etc. A refrigerant compressor is a machine used to compress the refrigerant from the evaporator and to raise its pressure so that the corresponding temperature is higher than that of the cooling medium. The condenser is an important device used in