The decision about the number of coils in their places in the refrigerator space and direction of air discharge are interrelated and influence of the geometry of premises, finishing of the ceiling and product placement. The sum of the cooling capacity of the heat exchangers must be equal to or exceed the design cooling load, but the number of coils in which the total capacity divided is a compromise. A small number of large coils usually leads to low cost and low maintenance costs) in connection with the reduction in the number of pipelines, valves and regulators for coils. On the other hand, the distribution of the total capacity in a large number of turns helps to avoid pockets of high temperature in space.
The goal of achieving a uniform temperature is dominant in the choice of a number of coils and their placement. Several recommendations are often used by system designers include:
select coils and place them on the basis of two steps from 30 m to 60 m (100 to 200 ft)
blow air blowing in the same direction, beams
kick in the door, and not from the city, or in relation to them (Fig.
6.39)
direct discharge of air down the aisles
direct discharge of air down from the ceiling coils of the high-rise storage
Sometimes, air injection served with the coil to pass it on, but most of the coils, probably, discharge directly into space. There is a danger of ducts in the conditions of low temperature spaces becomes dull without any means automatic defrosting. Coil sometimes mounted near the floor for ease of maintenance (Fig. 6.40), and the air duct to the ceiling. The dampers must be installed in the duct, and should close during defrost. Otherwise, warm coil creates the chimney effect that slows down the process of defrosting prices. One of the situations where floor mounted unit will be considered when the coils are installed in the existing facility, where the design of the roof may be unable to accommodate the weight of the ceiling-suspended or roof air conditioners.
A concept that is gaining popularity in the penthouse accommodation coils, as shown in Fig. 6.41. Coils are grouped in a penthouse and air is directed downwards, and then in various horizontal directions using a short duct elbow. Penthouse installation coils likely location of highest first cost, but there are some advantages to this operating concept11. Space which is available for storage of products or processing operations is not occupied by the coils. Location yield " safe installation than ceilingmounted reels, where the refrigerant is in the refrigerator space, where there is a danger of damage from collisions with the help of lift trucks. Valve groups needed for the hot-gas defrost are outside the penthouse, where they can be serviced by more comfortably, safely and effectively. Refrigerant is outdoors, above the roof. If there is a need for staff to work on the reels or the fans, they can stand on the metal bars on the floor of the penthouse. For such cases, you can manually enter the defrost, to warm penthouse over the space of temperature for a short period of time. Perhaps 15% of industrial refrigeration coils are now installed in penthouses.
Industrial 
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