The main purposes of thermal building-dynamics simulation are

• Energy-demand predictions for heating and cooling

• Energy-performance assessment of a building

• Evaluation of passive cooling options

• Thermal comfort assessments: room air and operative temperatures (but not draft risk evaluations)

• Determination of peak loads and dimensioning of HVAC system components

• Optimization of operation and control of HVAC systems

• Performance assessment of innovative HVAC systems, facades, and glazings

• Daylighting analysis (interaction with solar gains)

• Moisture transport

• Proof of compliance with building regulations or codes expressed in terms of either peak load targets or energy targets Combined and Integral Building Design

Combined thermal and multizone airflow models are needed for problems such as thermal comfort analysis in naturally ventilated buildings, determina­tion of heat-removal capacity by natural ventilation, design and evaluation of passive cooling by nighttime ventilation. This is outlined in more detail in Sec­tion 11.5.

For integral building design and performance assessments (thermal com­fort, indoor air quality, visual comfort), either integrated building simulation tools must be used or the thermal building simulation must be complemented by airflow and daylighting simulations.

The structural elements of a building consist of the envelope elements (exter­nal walls, floors, ceilings, roof) and internal constructional elements (internal walls). All these opaque (not light transmitting) elements are referred to as Walls in this section. Translucent elements are referred to as Windows.