Variable air and fan control in HVAC systems
Variable air and fan control is an essential aspect of maintaining energy efficiency in commercial buildings. It involves using controls to automatically adjust the supply air temperature and chilled water temperature in response to building loads or outdoor air temperature. This helps reduce energy consumption, improve system efficiency, and maintain a comfortable indoor environment.
Supply Air Temperature Reset Supply air temperature reset is an energy-saving control strategy that automatically adjusts the supply air temperature based on the building load or outdoor air temperature. The goal is to maintain a comfortable indoor temperature while minimizing energy consumption. The controls reset the supply air temperature to at least 25% of the difference between the design supply air temperature and the design room air temperature.
Chilled Water Temperature Reset Chilled water temperature reset is another control strategy that automatically adjusts the supply water temperature based on representative building loads or outdoor air temperature. This helps maintain a consistent indoor temperature while minimizing energy consumption. However, there are exceptions to this requirement when the supply temperature reset controls cause improper operation of equipment.
Variable Air Volume Fan Control Variable Air Volume (VAV) systems are commonly used in commercial buildings to control airflow to different zones. To maintain energy efficiency, fans in VAV systems should have controls or devices that result in fan motor demand of no more than 30% of their design wattage at 50% of design airflow based on manufacturer’s certified fan data. This helps reduce energy consumption and maintain a comfortable indoor environment.
In conclusion, variable air and fan control is an essential aspect of maintaining energy efficiency in commercial buildings. By implementing supply air temperature reset, chilled water temperature reset, and variable air volume fan control, building operators can ensure that their HVAC system is functioning efficiently and providing occupants with a comfortable indoor environment while minimizing energy consumption.