Air-handling units

There are three types of air-conditioning systems for large buildings.

1.Individual self-contained units are located throughout the building. Each unit contains a compressor, air or water cooled condenser, direct expansion cooling coils, filters, controls and blowers.

2.Central refrigeration plant. From this plant chilled water is pumped through coils in air-handling units placed adjacent to the conditioned area. The units consist of the cooling coils, fans, filters, and controls and may be either of the factory - built type or field assembled on the job.

3.Fan and coils units. This type also employs a central refrigeration plant, but whereas in the other two types duct work is required for carrying (he supplying air from the units to the conditioned areas, the type employs individual fan and coil units in each room, making duct work unnecessary. Central station systems do not present as many maintenance problems as Type 1, create less noise in conditioned, areas, are more economical to operate, and are more widely used for larger buildings.

10. Read the Text "Supply Systems" and say:

(a)if it has something to do with our text «Air - handling Units».

(b)make up list of different air-conditioning units.

(c)choose the characteristic features for each of them.

(d) prepare a report based on the information of both texts: «Supply Systems» and «Air-Handling Units».