SELECTION OF DEVICES

In order to find out the optimum number of heating-and-ventilation devices necessary to heat premises and continuously maintain the desired temperature, it is necessary to define the so-called heat demand. It will compensate heat loss in the premises (through the walls, floor, roof, gates, etc.).

Heat loss in a room depends on:

assumed external temperature in accordance with ASHREE Fundamentals Hanbook,

desired (target) temperature indoors,

type of building materials of which partitions are made and their thickness.

When heat demand is calculated, heat gains should be considered apart from heat losses. Heat gains may be caused by machines working indoors, office equipment and also people who generate heat and moisture.

One should not forget about heat demand in connection with the need to heat the ventilation air.

Below please find a simplified way to calculate heat demand which will allow you to find out the number of necessary heating and ventilation devices necessary to heat the premises easily.
The example was elaborated on the basis of figures and relations found in a guide book entitled, "Heating and air conditioning" by Recknagel, Springer, Hofmann, Schramek, EWFE Gdańsk 1994.