Using VSDs In HVAC Applications

Customers using HVAC are now demanding greener equipment to provide their heating, ventilation and cooling. Also, tightening regulations mean that manufacturers have to ensure that the pumps and fans they supply meet with these regulations.

As well as electrical efficiencies mechanical design solutions can be utilised. One mechanical solution is the replacement of a single supply or return fan with a bank of fans called a split or multi point system. These systems, by their nature, mean that building maintenance can be more complicated than with a traditional motor and VSD package. This issue can be further complicated by the huge variety of non-standard options that are available. Whilst providing a more local control these systems can often cause issues with maintaining nominal static pressure.

Split system fans and pumps utilise Electronically Commutated (EC) motors. The motor tends to be integral to the fan or pump with fan blades integrated in the outer casing of the fan. Should a bearing or motor fail this will involve the change out of the complete integrated unit leading to higher maintenance and life costs for the system. As the EC units are not standardised this can lead to prolonged downtime due to availability of replacement units and an over reliance on one supplier for units.

EC fans, due to the motor being fitted in line with the airflow, often have to be oversized to achieve and maintain the required airflow and therefore the motor is not running at its most efficient. With a traditional motor and drive package the nominal static pressure can be achieved and maintained without oversizing and therefore maximum running efficiency can be achieved.

Other advantages of the motor and drive package over the EC fan and pump are the ability to connect directly to most BMS or control systems as standard, use of standard industry sizes and therefore widespread availability and the ability of the drive to continue to operate when voltage is 15% below nominal.

The safe torque off functionality of the ABB drives ensures that the fan, pump or motor can be worked on safely without the need for complicated external components.

With guaranteed efficiencies, simple connectivity and reduced and safer maintenance IDS recommend fitting of the ACH580 and SynRM Motor package to HVAC systems.

Need Assistance?

IDS engineers have a wealth of HVAC experience and can offer this expertise during a free inital site survey, to book contact us 0115 944 1036 or email [email protected]