Thermal Model: The Future of Energy Modelling

If you have ever wondered why the predicted levels of energy consumption outlined at the design stage of a development do not quite match up to the actual figures once the building becomes occupied, it is typically related to several factors including;

• The type of software used to establish the predicted figures.
• The accuracy of the data in-putted into the software.
• Changes to the building’s specifications between the design and construction phases that were not updated into the software as the development progressed.
  

Most construction projects use basic calculation engines: 

1. SBEM for non-domestic buildings. 
2. SAP for domestic buildings.

These programmes do not include key design parameters such as:

• The impact of air flows within and around the building. 
• Shading from nearby property.
• Actual occupancy profiles and patterns. 
• Solar radiation.
• Internal gains from people.
• Lighting and equipment.
  

Thermal Modeling Software

The thermal model, known as dynamic simulation, is an advanced computer programme that is used by building designers and engineers to accurately predict the thermal performance of a building before it is constructed. The results produced by the simulation offer up valuable information that can be acted upon prior to the building reaching the advanced stages of design, making it possible to specify the most efficient materials and energy systems.

A thermal model provides valuable information on a room-by-room basis, including;

• Air temperatures at hourly intervals. 
• How a space will react to Solar radiation at various times of the day/month/year.
• The impact of heat gains from people.
• Electrical equipment and lighting (based on actual occupancy profiles).
• Plant sizing for heating and cooling.
• Impact of natural ventilation. 
• Shading from nearby buildings.
• Brise soleil.
• Benefits from renewable energies.

The use of thermal models as a design tool is of major importance in the growth of sustainable buildings. 

TWC Consulting advocates its use over basic calculations such as SBEM and SAP, as the simulation provides greater accuracy in predicting energy consumption levels, and  identifying conflicts within a design that can be acted on before the development reaches the as-built stage.