Building on the success of the exceptionally low-noise TD Silent, S&P (Solar & Palau Ventilation Systems Ltd) has enhanced the design further in the TD Silent Ecowatt, introducing improved energy efficiency and controllability. The result is what we believe to be the widest range of fans that have been awarded the Quiet Mark and satisfy the specific fan power requirements of the latest Building Regulations in the majority of applications.
The TD Silent range of low profile, inline, mixed-flow fans is a direct result of significant investment in product design by S&P and was the first range of commercial fans to be awarded the Quiet Mark (see below for more detail).
The TD Silent Ecowatt combines the advanced low-noise features of the TD Silent with an EC (electronically commutated) motor to deliver enhanced energy efficiency and facilitate more sophisticated control strategies, such as demand-controlled ventilation as well as standard trickle and boost requirements for schools, offices, health centres and many other commercial applications.
TD Silent Ecowatt fans are available in diameters from 100mm to 315mm, enabling the benefits of these fans to be applied to a wide range of applications – especially those where energy efficiency and noise levels are particularly important and, due to continuous operation, a significant energy saving is desirable.
Unlike axial fans where the airflow is normally axial, with mixed-flow fans the initial air flow is axial but is then deflected through 45 degrees by the impeller. The result is an increase in pressure due to the centrifugal force, making them ideal for overcoming the inherent resistance of ducted systems. At the same time, the design of mixed-flow fans retains the benefits of compact dimensions and low profile.
Energy saving design + ultra low noise + controllability
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TD Silent Ecowatt[/caption]
Using mixed-flow inline fans also contributes to energy efficiency as the mixed-flow configuration allows for a very efficient impeller. This, combined with the use of EC motors, ensures that the TD Silent Ecowatt provides very low specific fan power (SFP).
This is an important metric, as the current Part L of the Building Regulations requires fans to meet an SFP of 0.8W/l/s. TD Silent Ecowatt fans are able to meet this requirement at many different working points and system pressures, helping specifiers and installers to comply in a wide range of projects.
For example, the 250mm version uses 494% less electrical power to deliver the same performance as other inline fans, while the 315mm version reduces power consumption by 461%.
The design of the TD Silent Ecowatt also anticipates future changes in European regulations. Following on from the first wave of fan minimum efficiency grades (FMEG), which came into effect on 1 January 2013, there was a second, even tougher, stage at the start of 2015. The European regulation pipeline also has new minimum efficiency requirements scheduled to cover residential ventilation products and commercial ventilation products such as box fans, roof fans and air handling units.
As this legislation stands at the moment, it will probably signal the end of many product types and configurations that cannot deliver the required efficiencies. These include axial roof fans and just about any product fitted with a forward-curved centrifugal fan.
The mixed flow design of the TD Silent Ecowatt will provide the perfect compromise between energy-efficiency and ‘usability’ in many low to medium pressure ducted systems.
Controllability is only one element of differentiation
EC motors are highly controllable, making fan speed 100% adjustable using a 0-10V input signal. The difference with the TD Silent Ecowatt range is that it comes with an on board 10V signal voltage and potentiometer that allows a trickle ventilation rate to be set.
This can then be switched via an external sensor (CO2, PIR, RH%, IAQ, Timeswitch, etc) to give a higher-boost airflow as required without the need for any other interface. Most competitor ventilation systems that provide adjustable Trickle and Boost settings involve the use of expensive and unnecessarily complex ‘smart’ controllers; with the TD Silent Ecowatt, this is integral with no additional cost or complexity. The TD Silent Ecowatt is unique, as none of its competitors can match the combination of such low noise levels, low energy use, low profile and flexibility of control.
EC motors also provide a constant torque so that efficiencies are maintained at all fan speeds – taking full advantage of the fan cube law whereby a 50% reduction in fan speed results in power being reduced by a factor of eight times.
To put this into perspective, if a fan has a normal speed of 2,000 rpm to deliver air flow rates of 1,260m3/h with an absorbed power figure of 200W, the SFP is 0.57W/l/s. If the speed is halved to 1,000 rpm, the duty is halved to 630m3/h but the absorbed power is reduced to approximately 25W. Thus the SFP is only 0.14W/l/s.
Use of EC motors provides a more efficient solution than the use of variable frequency drives (VFDs) as these are subject to typical motor losses of 2-5%, though these can be as high as 20% (based on guidance in IEC60034-31). VFDs also have small inherent losses which vary with drive switching frequency.
The result is that TD Silent Ecowatt fans are ideally suited to applications where ventilation needs to be aligned to usage of the space, such as in Demand Controlled Ventilation, to achieve maximum energy efficiency. As Demand Controlled Ventilation becomes the standard requirement for many ventilation systems this functionality of the TD Silent Ecowatt will prove increasingly useful.
Whisper quiet
Low-profile inline fans are often installed in false ceilings or other locations close to the space they are ventilating. Consequently, noise is even more of a critical issue that it might be with some other fan types.
S&P has invested heavily in R&D that has led to the noise reduction measures incorporated into TD-Silent Ecowatt fans. These include a specially developed sound-absorbing perforated lining which provides integrated attenuation and sound absorbing insulation in the external skin of the fan. As sound waves are produced inside the fan they are directed through the perforated inner skin and absorbed by the insulation in the outer skin.
In addition, TD-Silent fans feature a specially modelled, aerodynamic inlet that reduces sound further, as well as improving airflow. Motor vibrations are absorbed by a twin-material support bracket for the motor section.
The overall result is that sound levels are reduced by as much as 7dB(A) less than a box fan with the equivalent performance. As a consequence, TD-Silent Ecowatt fans of all sizes have been awarded the Quiet Mark. This is a mark of approval from the Noise Abatement Society given to the manufacturers of the quietest products on the European market. Crucially, the Quiet Mark is only awarded following rigorous testing and independent verification by the Association of Noise Consultants.
The design of the TD Silent Ecowatt addresses two key factors that influence fan specification and end user requirements – energy consumption and noise. As such, they provide specifiers and installers with the opportunity to deliver added value solutions to their clients, while also helping to reduce the environmental impact of the ventilation system.
For more information on the TD Silent Ecowatt, please click here.