Improved modelling of HVAC system/envelope inteactions in residential buildings

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

OSTI ID:273737

Modera, M P; Treidler, B

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 thermosiphon 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. Thermosiphon 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.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); California Inst. for Energy Efficiency, Berkeley, CA (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 273737
• Report Number(s): LBL--36048; CONF-950336--31; ON: DE96012515
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
AIR FLOW
COMPUTERIZED SIMULATION
DUCTS
HEAT TRANSFER
MASS TRANSFER
MATHEMATICAL MODELS
RESIDENTIAL BUILDINGS
SPACE HVAC SYSTEMS
VENTILATION SYSTEMS