introducing airconditioning systems

Air Cooled Chiller Selection Tips :

The vapor compression chiller is employed to supply water or cold gaseous refrigerant in AC or industrial refrigeration systems operating at 7–12 C (depending on the application and requirements) by the vapor compression refrigeration cycle.

Air cooled chiller, as a type of vapor compression chiller, serve as the heart of the cooling system for buildings in climates with high Relative Humidity (RH) where it is not possible to use cooling towers and water-cooled chillers. Air cooled vapor compression chillers, which are often installed in open spaces (such as rooftops), operate by the vapor compression refrigeration cycle similar to water-cooled chillers.

The main reason for installing air cooled chiller in an open space is for the condenser to be capable of thermal exchange with fresh air.

The Main Components of Air Cooled Chiller

•     Compressor
•     Condenser
•     Evaporator
•     Expansion valve

A larger amount of refrigerant circulates the air cooled chiller, and at a higher working pressure, than water-cooled chillers, which is cooled down in the condenser by forced convection, entering the cooling coil of the water-cooled DX air handling unit or the evaporator DX. It is important to note the difference between the nominal and actual capacities of the chiller—particularly, considering the local design outdoor summer temperature. Further, note whether the condenser and chiller heat transfer surface area—as determining factors—at the claimed capacity (length, size, and the number of tubes used in the condenser and the evaporator) are sufficient. Air cooled chiller (including an air cooled condenser, gaseous refrigerant, and oil) are 1.5 times more expensive than water-cooled chillers of a similar capacity.

In general, to calculate the required chiller capacity in a project, based on the exact total refrigeration load, facilities engineers take into account the amount of required cold water and safety factors for the correct function of the chiller in addition to such parameters as the climatic conditions (ambient temperature), the design outdoor summer temperature, elevation, relative air humidity, building use (design indoor temperature), type of incorporated materials and the facade, orientation of the building relative to the sun angle, number of residents and small or large electrical equipment in the building. However, as a rule of thumb (phase 1 calculations), the required nominal capacity for residential and office buildings in a climate similar to Tehran can be estimated by 4 tons of refrigeration per 100 square meters of effective floor area.

Further, before determining the final capacity and selecting an air cooled chiller, contact our specialists at

DamaTajhiz for consultation and controlling the estimations of the refrigeration load for accuracy.