Focusing on energy efficiency

Energy efficiency in machinery and equipment is one of the main issues facing industries on a daily basis. There is still significant potential for innovation even in tried and tested technologies such as the climate control of electronics enclosures.

Rittal’s new range of  energy-saving cooling units, the "Blue e" generation, have cooling outputs ranging from 500 W to 4,000 W. The new enclosure cooling units have proven their potential for efficiency in pilot applications in the automotive industry.

Compared to standard cooling units of the same power, the new cooling devices, with a cooling output of 1,000 W, consumed up to 70% less energy in the field test.

The higher efficiency of the new cooling units stems from the optimal interaction of all the components responsible for the cooling output.

The first step to improving efficiency covers the entire geometry of the cooling technology construction. Here, the component manufacturer has systematically analysed existing devices and modified them for increased efficiency.

This includes, for example, the design of the condensers, evaporators, cooling fins, pipe bends and all the other cooling components.

In a second step, the fan technology has been improved. Now predominantly EC (electronic commutation) fan motors are used, which have a very high efficiency over the entire speed range. Precision bearings ensure a long service life and low noise generation.

Thirdly, Rittal has improved the control electronics through the new Eco-Mode control system. If continuous operation of the internal fan is not required, it is shut down automatically, thus saving energy costs.

The fact that there is still potential in traditional enclosure air conditioning with fan-and-filter units was demonstrated at the Hanover Trade Fair in 2011 with Rittal's introduction of a new performance class – 900 m³/h – of its TopTherm fan-and-filter units.

These are fitted with the above-mentioned energy-saving fan motors with EC technology. So-called "diagonal fan technology" is employed, as with the other current TopTherm fan-and-filter units.

These fans, which represent a synthesis of radial and axial flow fans, are characterised by the fact that the air outlet direction is not in the fan's axial direction, as had been the case up to now, but instead diagonally to the outside.

This favours an even distribution of air in the enclosure, and avoids the formation of hot spots. In addition to the flat design, the key advantages are the steeper curve and the higher pressure saddle.

Energy efficiency in machinery and equipment is one of the main issues facing industries on a daily basis.The result is improved higher pressure stability and – when installed under operating conditions – a larger and more constant air flow over a wide area. This in turn leads to an increased operating life for the filter mats without having to settle for any power losses in return.

To ensure increased security in enclosure climate control, the new TopTherm fan-and-filter units can be monitored and regulated by an Eco control unit, available as an accessory.

Benefit: In the event of a fan defect, an error message is actively triggered by the speed (tacho) signal from the fan. This allows a reaction at an early stage, before the internal temperature in the enclosure increases. In addition, energy-efficient climate control is possible with the temperature-dependent speed control system.

There has also been an improvement in the air-water heat exchanger, which transfers heat in the enclosure to the cooling water.

The highlight in terms of energy efficiency is the new Eco Mode control. This intelligent control unit switches the fan on or off as needed, depending on the temperature in the enclosure.

If the internal temperature is 10 °C below the set point temperature, the fan switches off. To measure the effective internal temperature in the enclosure, the controller switches the fan on for 30 seconds every ten minutes, so ensuing circulating air in the enclosure.

The company is now offering new TopTherm Chillers to provide cooling water for air-water heat exchangers in applications where no central supply is available in the production plant.

The modular design uses just a few components: The basic module is the TS 8 enclosure system. It also includes the water and cooling modules, as well as an electrical module with integrated controls.

The water module consists of a tank (in other words, an open system), a pump and control technology. The cooling module comprises a compressor, condenser and evaporator.

The design of the Chillers is largely based on the required cooling output and the boundary conditions at the installation site. The enclosure of TopTherm chiller is available in two basic widths, 800 and 1200 mm. Height and depth are always the same: 2000 and 800 mm.

The cooling modules in the narrow enclosure achieve cooling outputs of 8, 12 and 16 kW, depending on the compressor housing and the size of the condenser, or 20 and 25 kW with the wider enclosure.

Outputs of 32 or 40 kW are possible (2 x 16 = 32 kW and 2 x 20 = 40 kW) if the enclosures are combined. Thus the operator has the choice of seven different cooling capacities with just two different sizes.

[Troy Gersback is Marketing Coordinator, Rittal.]