Supply cooler air
As a rule. outside air temperatures are considerably cooler than those
inside a building. As superheated air is exhausted, provision should
be made to replace it with fresh, cooler, outside air. Exhaust air
in many areas of a building may have a temperature of 125° to 150°.
This is usually the case where heat-producing machinery is in use.
Similar air temperatures frequently occur near the roof or ceiling
where rising warm air is trapped and further heated by the sun load
on the roof.
When this high temperature air is replaced by outside
air, a substantial improvement in the average air temperature of the
building results. Even where outside air temperature may be in the
80s or 90s, invariably it is 15° to 20° cooler than the air it replaces.
This is a very important improvement to the individuals affected.
Supply
cooler, fresh air
Breeze
conditioning
A very effective way to overcome the
discomfort of a hot, stuffy room is to create a breeze. Before refrigerated
air systems were invented, mechanical fans of every description
were used to provide air circulation.
The circulation of
air over a person's body immediately causes a cooling effect on
the skin. When air is passed over a moist surface, it will evaporate
some of the moisture and thus lower the temperature of the surface.
This is precisely what occurs when air circulates across the human
body.
Create
a breeze
By creating a gentle breeze throughout
a room or area, a great deal of cooling comfort is provided for
individuals who must work there. This pattern of air circulation
is called "breeze conditioning" by American Coolair engineer.. It
is effective even when the air temperature may be 85°' to 95°. When
this air circulation is achieved in combination with the factors
mentioned in the paragraphs above, a very effective and practical
solution is provided for the problem of personnel discomfort in
hot weather.
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Benefits
A work stoppage or strike may occur if the problem of personnel discomfort
is unresolved. The benefits from a solution to such a situation are
enormous. In plants where there is a high density of employees and
many manual operations involved, an improvement in the environment
can produce substantial benefits in terms of increased production,
reduced errors, and a decline in complaints and absenteeism among
employees. In other circumstances, the attentiveness of an audience
or student group may be a factor that spells success or failure for
the project.
There is an American Coolair case history
where a high ambient temperature had actually reduced the capacity
of a big power turbine. To obtain rated performance by the machine,
an improvement in the room ventilation and cooling system was necessary.
When this was accomplished, the plant management was amazed to find
an equivalent improvement in the efficiency of the employees who were
required to work in this same environment with the machine.
Available
cooling methods
The three basic considerations outlined in A practical approach
should he used as yardsticks to evaluate the methods of cooling
being considered to solve the personnel discomfort problem. Commonly
available methods that should be considered are:
Exhaust
fans or Power Roof Ventilators (PRVs)
Almost every building has some type of ventilators to vent hot or
contaminated air from the structure. As a rule, this equipment is
inadequate for anything more than safeguarding the health of the
occupants. In some cases, it does an inadequate job of this.
To do a satisfactory job of eliminating
excessively hot air, it is usually essential to have powered wall
and/or roof exhausters. These fans should also help to control air
pressure within the building whether it be negative or positive
pressure.
The most effective way to incorporate wall
or roof exhausters into a system will be discussed in the sections
that follow.
Propeller
Fan-----Type C
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