Improved modeling of HVAC system/envelope interactions in residential buildings

Conference · Wed Nov 01 04:00:00 EST 1995

OSTI ID:113312

Modera, M P; Treidler, B ^[1]

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1. Lawrence Berkeley Lab., CA (United States). Indoor Environment Program

General building energy simulation programs do not typically simulate interactions between HVAC systems and building envelopes. For this reason, a simulation tool which includes interactions between duct systems, building envelopes, and heating and cooling appliances in residential buildings has been developed. The simulation tool uses DOE-2 (to model space conditioning loads and zone temperatures), COMIS (an airflow network solver), and a model of duct leakage and conduction losses. Three augmentations to the simulation tool are presented herein, along with sample results. These include: (1) modeling of steady-state thermosyphon flows in ducts, (2) improved simplified modeling of duct thermal mass effects, and (3) modeling of multi-speed space conditioning equipment. Multi-speed air conditioners are shown to be more sensitive to duct efficiency than single-speed equipment, because their efficiency decreases with increasing cooling load. Thermosyphon flows through duct systems are estimated to be 5--16% of the total heating load, depending on the duct insulation level. The duct dynamics model indicates that duct thermal mass decreases the energy delivery efficiency of the distribution system by 1--6 percentage points.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 113312
• Report Number(s): CONF-950336--; ISBN 0-7918-1300-2
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
BUILDINGS
C CODES
COMPUTERIZED SIMULATION
D CODES
DUCTS
SPACE HVAC SYSTEMS
THERMOSYPHONS