Initial Design Considerations The modes of heat gain

By admin on November 14th, 2007

Initial Design Considerations

The modes of heat gain in a space may include solar
radiation and heat transfer through the construction
together with heat generated by occupants, lights and
appliances and miscellaneous heat gains as air
infiltration should also be considered.
Sensible heat (or dry heat) is directly added to the
conditioned space by conduction, convection and
radiation. Latent heat gain occurs when moisture is
added to the space (e.g., from vapour emitted by the
cooking process, equipment and occupants). Space
heat gain by radiation is not immediate. Radiant
energy must first be absorbed by the surfaces that
enclose the space (walls, floor, and ceiling) and by the
objects in the space (furniture, people, etc.). As soon
as these surfaces and objects become warmer than
the space air, some of the heat is transferred to the air
in the space by convection (see picture 2).
To calculate a space cooling load, detailed building
design information and weather data at selected
design conditions are required. Generally, the following
information is required:
building characteristics
configuration (e.g, building location)
outdoor design conditions
indoor design conditions
operating schedules
date and time of day
However, in commercial kitchens, cooking processes
contribute the majority of heat gains in the space.