Tangential blower with EC motors and multiple housings for building HVAC

By Helen McHugh - Head of New Product Research - 17th January 2018

Introduction

Reducing energy consumption within buildings is still a key consideration for all businesses, however there is also a growing interest in building automation. By increasing the functionality and controllability of the equipment within a building, it is possible to maintain optimum conditions for the occupants and at the same time, reduce operating costs. A smart building is one where functions such as lighting, HVAC, lifts etc, can communicate with each other and adapt to meet the changing needs of the occupants.

HVAC is one of the main considerations in any modern building, and to meet the demands of a smart building it is essential it has the flexibility to respond quickly to meet the variable demands, whilst also delivering energy efficiency and reliability. GreenTech EC fans are key to delivering optimum performance and flexibility of HVAC equipment. With built in speed control, they can adapt to meet changing demands, they are also able to communicate with each other and with the Building Monitoring System (BMS), giving essential information for ensuring reliability of operation and consistency of service. EC fans also deliver significant energy savings and have an extended life expectancy compared to AC fans.

A specific example of EC fans being used in smart buildings, for both commercial and domestic HVAC equipment, are the new EC tangential blowers from ebm-papst. The tangential blowers are ideally suited to use in convection heaters, where they not only lower the energy consumption but also have variable speed control, reduced noise and increased life expectancy.

Tangential blowers have a cylindrical forward curved impeller which is much longer than it is wide - combining a compact cross-sectional size with long fan lengths. The large air intake and discharge area delivers a high volume of air at low flow rates, and provides uniform airflows across the entire length of the blower; also the low air velocity means that noise levels are very low.

Ideally suited for applications where an even flow of air is needed across a wide surface, such as a heater coil for convection heating. Other key applications include Air curtains, and electronics cooling.

ebm-papst’s tangential blower range uses high efficiency EC motors; which, when compared to the traditional AC motors, are much more energy efficient, have lower noise levels, increased reliability and life expectancy. They also benefit from variable speed control and connectivity. Available with either single or multiple housings, up to 3 impellers can be driven by a single motor, this increases the maximum surface area and provides a uniform airflow across the blower.

ebm-papst Tangential range

The new tangential blowers available in single or multiple housings, and benefit from GreenTech EC technology.

Key features:

  • Steady and consistent air flow
  • High air volume at low velocity
  • Very low noise (with vibration cushioned suspension)
  • Optimised space utilization (multiple housings)
  • High efficiency
  • Long service life
  • Continuously variable speed via PWM or 0 – 10v signal.

To deliver uniform airflow over the widest possible distance, the fans are available with multiple housings - up to 3 impellers being driven from a single motor. The impellers are precisely aligned and the housings joined by a unique coupling system with two maintenance free ball bearings.

The multiple housings are available in impeller diameters of 45, 60 and 65mm and overall lengths of up to 900mm, with airflows to 840m3/h. Larger diameter single impellers are also available.

The GreenTech EC motors enable the fans to run at a higher speed than the traditional AC motors, delivering higher airflow as well as higher pressures. The on-board control allows the fan speed to be optimised and adjusted automatically to provide the exact amount of air needed.

The motor also offers very high efficiency and virtually silent operation, and is available with both AC and low voltage DC input voltage.

Convection Heating – Advantages of using EC technology

One application benefiting from EC tangential fans is floor convection heaters or trench heaters; these are used in commercial buildings such as offices, schools and hospitals, as well as domestic homes.

These products are installed beneath windows to eliminate draughts and heat loss from the window area, and often used where there is floor-to-ceiling glass. When fitted into a trench at the perimeter of a building close to the glazing, the warm air rises over the window and reduces cold down draughts and the likelihood of condensation. Once installed these units require little or no maintenance.

Case Study – Trench Heaters

A leading British manufacturer of trench heaters SPC Ltd is using the GreenTech EC multi housing tangential fans in its high output trench heaters, which are used widely in commercial buildings. The use of EC fans enhances the performance and controllability, and also significantly improves energy efficiency and noise levels.

One project recently completed, was the refurbishment of a restaurant within a 5-star hotel. The customer wanted high heat outputs that could adapt to meet their changing demands, the solution also needed to be extremely quiet and energy efficient.

The Trench heaters fitted incorporated the EC twin impeller tangential blowers. The high output of the EC fans enabled SPC to meet the performances required, whilst consuming 50% less power than a conventional unit using AC fans. The customer was impressed by the energy savings, however it was the ability to control the units that the customer was most impressed by. The units were connected to the BMS, allowing the airflow and heat to adapt automatically to meet their changing needs. The units were also fitted with a potentiometer which allowed manual adjustment if required.

SPC have found that the principle advantage of their system is the controllability of the fans via a 0-10V signal. The majority of installations for these trench heaters now use some form of central control. The speed control and added functionality of EC technology makes these Tangential blowers an ideal solution. The fan has also been described as "whisper quiet" once installed, which again is perfect for this type of noise sensitive application.

For enquiries and further information about this article, please contact Hannah.Morphew@uk.ebmpapst.com