DOE-2 Engineers Manual Version 2.1A - DOE-2.com

2. DESIGN CALCULATIONS (Subroutine DESIGN)
Overv iew
The design subroutine (DESIGN) ensures that all the various quantities needed
for the system simulation are given values. These values are either
(1) specified by the user,
(2) defaults built into the program, or
(3) calculated for peak cooling and heating conditions that were
determined in the LOADS program.
This subroutine also ensures consistency among the multiple values of related
data. The hourly simulation requires:
(1) a value for the air flow rate (for air systems) for each conditioned
zone,
(2) a heating and cooling capacity for each system, unit, or coil,
(3) the electrical consumption of fans and direct expansion
condenser-compressor arrangements,
(4) minimum and maximum air flow rates for variable-air volume flow
equipment,
(5) outside ventilation air flow rates, and
(6) other controller set point or operational information.
Because the built-in calculations of this subroutine may not always do things
as the user wishes, it is sometimes necessary for critical keywords to be
specified in such a manner that will result in the desired sizing.
The design calculations are performed for each SYSTEM specified in a PLANT­
ASSIGNMENT instruction and for each ZONE in one of these SYSTEMs. The results
of the calculations can be found in the SYSTEMS verification report, SV-A.
Calculation Outline
A. Correct the zone peak heating and cooling loads if the user has specified
SIZING-OPTION = ADJUST-LOADS in the ZONE instruction.
For each SYSTEM that has a PLANT-ASSIGNMENT instruction:
B. Calculate the supply air and return air fan heat gain and energy consumption
at the design air flow rate.
C. Calculate for each ZONE attached to this SYSTEM
1. the outside ventilation air flow rate,
2. the total zone supply air flow rate,
3. the heating capacity for zone coil systems (zonal systems),
4. the cooling capacity for zone coil systems (zonal systems),
5. the minimum supply air flow rate for non-zonal systems (central
sys tems ), and
6. the sum of the various quantities needed for the central air handler
calculation, if present.
IV.25