Modern Heating and Ventilation

Ventilation means the circulation of air without any treatment. Ventilation is used where the cost of air conditioning is not justified. Ventilation may be natural or mechanical. Natural ventilation is due to the action of wind through wall openings and the updraft caused by the difference in temperature between indoors and outdoors. The limiting factors in natural ventilation are usually cold weather conditions and the availability of heat. Buildings with small floor areas are ventilated by natural means. Natural ventilation has the advantage of being cheap to install. Mechanical or artificial ventilation is used for theatres, factories, large public halls and other buildings with large floor areas. Artificial ventilation may be classified as follows: exhaust ventilation, plenum ventilation and some combination of the above mentioned systems. Heating and ventilation may be required to provide comfortable conditions for people and for industrial processes. Both are necessary and should be considered together. But the design of each must be treated separately. Heating and ventilation of buildings by electrical methods are finding their application nowadays. These methods have the advantage of being quick in construction. They are suitable for buildings of all sizes and types. Small rooms can be adequately heated with electric fires. Tubular heaters are used for rooms where the temperature must be maintained for long periods. These heaters are usually fixed to the walls near the floor. Not long ago electrically heated panels were developed. On these the heating elements are mounted behind metal panels. The heating of rooms by means of large warmed panels is named panel heating or radiant heating. Electric heaters play a large part in the air conditioning plants of large buildings. The air enters the building through the ventilation ducts and passes over electric heaters. They raise the temperature of the passing air and give comfort to the people.

Дата добавления: 2015-07-25