Sizing the Central Unit - Verasys - LIT-12012331 - General System Information - Verasys System - 4.0

Verasys System Changeover Bypass Zoning System Design Application Note

Brand
Verasys
Product name
Verasys System
Document type
Application Note
Document number
LIT-12012331
Version
4.0
Revision date
2020-03-24
Language
English

When sizing the central unit, use a dependable load estimating program to calculate the individual zone loads. Select the central unit for the instantaneous peak load instead of the sum of the peak loads to ensure load diversity. A constant volume single zone system also uses this method. Consider the following guidelines when you size the central unit:

  • Size the peak cooling load based on the month, day, and hour of the greatest total building system load.
  • Size the heating load for the lowest design temperature with an additional margin for morning pickup. This margin is generally 20% to 25% of base design.
Note: In addition to unit size, consider that RTUs with multiple heating stages tend to provide better temperature control than single-stage RTUs.