One of the most successful energy management ‘tools’ ever applied to building HVAC systems is the variable frequency drive (VFD).

For more than 20 years, VFDs have successfully been installed on fan and pump motors in a range of variable load applications. This has resulted in energy savings varying from 10 to 35 percent (over conventional constant speed applications). Consequently, this equates to a return on investment between one to three years.

Arguably, the largest ‘pump’ in your HVAC system, is the chiller compressor(s) which has the largest draw of energy usage. Therefore, by applying a VFD to your compressor, it can result in effective energy and  cost savings. In other words, a great return on your investment.

Most conventional buildings are designed for their HVAC systems operating at full load, where in most cases, they only utilise the full load capacities for short periods of the year. Therefore the need for improved part load performance is in greater need now, than ever before. This means that by applying an energy saving modernisation kit, the McQuay / Daikin and third party manufacturer chillers can achieve just that.

The most significant benefit to using a VFD is energy savings.

Match system capacity to the actual load throughout the entire year. This results in major savings in system motor energy use.

Reduced wear and tear on the motors.

When an induction motor is started, it draws a much higher current than during normal operation. This inrush current can be three to ten times the full-load operating current for the motor. This will generate both heat and stress in the motor’s windings and other components. In motors this start and stop frequently results in early motor failures. In contrast, when a motor connected to a VFD is started, the VFD applies a very low frequency and low voltage. Subsequently, both are gradually ramped up at a controlled rate to normal operating conditions, which results in extended motor life.

VFDs also provide more precise levels of control of applications.

The compressor motor operates at full speed and the loading and unloading of the compressor is done so internally, in a mechanical way. When applying a modernisation kit (VFD) we fix the compressor at full load (mechanically) and oscillate the compressor motor to control the load required. This results in less energy usage.

Part of the Modernisation Kit is to also upgrade the controls. This can be upgraded to the modern Siemens controllers. Upgrading the controls, will result in easier connection to ‘Daikin on Site (DoS),  Daikin Applied’s  24/7 remote monitoring system.

Where HVAC equipment repair is not an option, we can optimise your buildings’ overall efficiency and energy performance through the following:

– Equipment servicing and surveys
– Plant and equipment replacement
– Performance contracting and design underwriting
– Installation and commissioning
– Energy efficiency packages
– Building energy rating surveys
– Self-financing
– Building management system (BMS) advice