During the heating season, a portion of heat loss is attributed to the infiltration of cooler outside air into the interior of the structure through cracks around doors and windows and other openings. The amount of air entering the structure by infiltration is important in estimating the requirements of the heating system, as well as composition of the air.
A pound of air is composed both from dry air and moisture particles, which are combined so that each one retains individual characteristics. The distinction of these two basic components of air is important, because each involved with a different type of heat; dry air with specific heat, and moisture content with latent heat.
Each heating system must be designed with the capability of warming the cooler infiltrated dry air to the temperature of the air inside the structure. This amount of heat referred to as sensible heat loss and is expressed in Btu/hr.
The most common methods of calculating heat loss by infiltration are:
1) the crack method;
2) the air-change method.
No comments:
Post a Comment