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energy technology  |   Article

Saving energy

The ‘challenge of saving energy’ is a central issue for the future, concerning the cooling of power electronics in industrial production

In view of the growing global climatic and environmental problems, existing resources must be used effectively, economically and in a socially acceptable way. Intelligent climate control technology can make an important contribution.

S tarting from a very low basic level in the 1960’s, the cost of energy has now reached a level that exceeds even the most pessimistic forecasts of the past. Short-term falls in the oil price rise curve, as an indicator for all forms of fossil-fuel energy, will not counteract the long-term price trends. Aside from the need to maintain the quality of environmental life, it is also an economic necessity to take every opportunity for saving energy that arises.

The quality sign on cooling devices can likewise be an important aid to make decisions. It guarantees that the refrigeration factor on the rating plate or the catalogue is achieved and adhered during operation. Rittal India has traditionally been a pioneer and trendsetter in such energy saving innovations.

Energy efficiency course

The decisive steps towards energy-efficient climate-control solutions start before the installation of the cooling systems and is usually built a long time before the first prototype. Powerful planning instruments and auxiliaries like computer-assisted project engineering tools, which, through computational fluid dynamics (CFD) simulation, and testing in well equipped heat laboratories and optimisation by means of thermography, lead to optimally dimensioned and energy-efficient cooling solutions. Nevertheless, there are limitations; the selected cooling components need to be scalable so that if necessary, a later extension is possible should additional users be assigned to the enclosure. Cooling units from experienced system suppliers offer such possibilities.

Keeping cooling outputs constant saves energy

Building and employing cooling units with a high refrigeration factor is one side of the coin, keeping the cooling capacity constantly high during the operating lifetime is another. Chiefly because the cooling capacity of the cooling units and the upstream-connected air filters is rapidly and severely affected by the contamination of the cooling fins. Energy consumption rises as a result. With conventional enclosure cooling units, power losses of 30 to 50 per cent can be expected after a brief operating time when the environment is burdened. The only remedy is to ensure maintenance or replacement of the filter element at very early on.

Rittal’s TopTherm Plus cooling units have a novel, gleaming nanocoating on the surface of the condenser package. This provides a thin sealing layer on the cooling fins, where the nanoparticles arrange themselves and fit together in a seemingly ‘intelligent’ way. A polymer structure is formed that is extremely hard and as smooth as glass, thanks to the high amount of carbon contained. Due to the lower amount of contamination, the condenser remains clean for far longer, meaning that filter mats are often unnecessary. Where it is not possible to do without mats, easy-to-clean and reusable metal filters can be used instead of fleece filters that rapidly deteriorate.What does this mean in practice? The intervals for maintenance work are extended and the cooling outputs remain at a constantly high value for a longer time. University research confirms the unique characteristics of this surface. Scanning electron microscopy has shown that there is a mirror-smooth, sealed structure instead of a ‘jagged’ aluminium surface. Even in environment contaminated by dust and oil vapours, there was no sign of any appreciable drop in cooling capacity over an observation period lasting several months. No additional cleaning was needed.Overall, cooling units of this type make an active contribution to reducing CO2emissions because of their consistently high cooling capacity and also due to their built-in energy efficiency, which is much higher than the industry average. Comparisons show that this leads to generous savings in terms of money and CO2. Rittal climate control units have refrigeration factors of up to 2.30. In contrast, many conventional cooling units only have a factor of 1.64. Thus, if 200 units are in operation (a figure that is not unusual in production lines and factory control systems) extra energy costs of more than Rs 2.3 million per annum are possible over an operating period of 16 hours per day on 250 days per year and with a full load to idle running ratio of 60 to 40 per cent (assuming a rate of Rs 7.50 per kWh). The different CO2balance is also clear: The climate control units with the higher refrigeration factor generate 203,000 kg less CO2per year than the comparable units stated. That is the real bonus - not only monetary, but also, and above all, for the environment because only around three per cent of the greenhouse effect of electronic enclosure cooling systems are the result of the refrigerant - on the other hand, 97 per cent is due to the energy consumption and the carbon dioxide involved.

A change is on its way

A Europe-wide ban of the refrigerant R134a has been the subject of discussion for a long time. In years past, Rittal investigated many possible refrigerants and is already prepared for climate change. CO2cooling units are the favourites. Their development has been successful, and roof and wall-mounted versions in this technology have been exhibited at previous trade shows and are ready for series production. This solution is neutral in terms of the greenhouse effect, as the gas required is reclaimed directly from the atmosphere. In other words; no additional emissions from fossil fuels are caused.

The future

The need of the hour is to use energy in a responsible and economical way from an ecological and economic perspective. Holistic system solutions are thus called for in cooling industrial and electronic enclosures and modern process control technology. This will enable achieve very high accuracy and performance with the best possible energy balance.

Rittal is conducting wide-ranging basic research and advance development at its global headquarters in Herborn. The energy-saving switch-off of the internal fan by a master signal in the event of a production standstill has already been implemented. The use of fuel cells, as a particularly safe, low-maintenance and ecologically undisruptive technology in outdoor applications has already begun.

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