December 2021

36 | Plant & Works Engineering www.pwemag.co.uk Annual Buyers’ Guide 2022 Energy & Environmental Management Focus on: HVAC V SDs are connected to more motors than ever in HVAC systems because they can provide significant energy savings. This is due to better speed control. In applications where traditional belts or gearboxes are used to lower speed, the motor still runs at full speed. Conversely, using a VSD in the same way serves to actually reduce the motor speed. The upshot of this effect is that fewer amps are drawn by the motor. In turn, there is less energy consumption, resulting in lower energy bills. But, this isn’t the only reason VSDs are the best choice for HVAC systems. Optimal capacity modulation HVAC systems are designed to function at peak load, even though this requirement only occurs for a relatively short period of time in any given year. As a result, one of the most effective ways to improve the energy efficiency of a HVAC system is to make use of a VSD. The VSD can be deployed to vary the speed of one or more motors based on load requirements. Dramatic cuts in energy consumption can therefore be achieved. Precise levels of control The use of VSDs for HVAC applications provides more precise levels of control. A system utilising a VSD can exert more precise control over a wider range of flow rates and output, while simultaneously reducing energy requirements and pump wear. For example, a pressure sensor placed inside of an air duct can provide feedback to a drive (Proportional- integral- derivative) PID regulator, comparing desired pressure with actual pressure and delivering optimisation by adjusting the How can VSDs make HVAC applications more efficient? One way to make heating, ventilation and air-conditioning (HVAC) systems more efficient is through the use of variable speed drives (VSDs),as Marek Lukaszczyk* explains.