Page 172 - TCDB combined Book

148 The Complete DESIGN BUILDER

Building Design:

HVAC Design Calculations (Heating & Cooling)

The climatic information necessary to complete the calculations are available through building
codes and other publications issued for this purpose (see appendix) and will depend on the
geographic location (degrees latitude etc.) and time of day selected etc.. The inside design
temperature can be personal preference or published comfort standards, depending on the
intended use and occupancy. The factors for heat gains and losses are based on published figures
(see appendix) for the types of construction assemblies (U values) and corrections for particular
circumstances and special situations.
.

Cooling Load Calculations

There are many variables in calculating cooling requirements. The method described here and the
chart below is based on heat gain calculations that should result in a reasonably accurate level of
cooling load for pricing purposes. All design calculations should be reviewed by an experienced
design professional prior to finalizing your pricing or preparation of actual working drawings

Where: G (gradient) = difference between outside summer and inside comfort design temp.
A = area of transmission surface
F = factor or U value of transmission loss item
BTU = cooling load in Btu/hr

Therefore:

G x A x F = Btu/hr (cooling load)