How is the total heat load affected by external gains in a commercial building?

The concept behind total heat load in a commercial building is that it is influenced by various factors, including both internal and external heat gains. External gains refer to heat that enters the building from outside sources, such as sunlight (solar heat gain) through windows, heat from the outdoors, and other environmental factors.

When calculating the total heat load, it is essential to consider both external and internal gains because they both contribute to the thermal energy within the building. Internal gains often come from occupants, equipment, and lighting within the building. To determine how much cooling or heating is necessary to maintain desired indoor conditions, the total heat load is calculated by summing these external gains with the internal gains.

This combined total provides a comprehensive view of what the HVAC system needs to address to maintain a comfortable environment. Therefore, recognizing that external gains are added to internal gains is crucial for accurate HVAC load calculations and ensuring energy efficiency in the building design.