Saving energy the cool way

26 May 2010

As a large user of energy, Broadcast Australia is always on the lookout for energy-efficiency initiatives in order to reduce our carbon footprint. A redesign of the digital transmitter sites’ cooling systems has proved how much energy can be saved with a little bit of lateral thinking.

It is widely accepted that the broadcast industry is a large consumer of energy. However, Broadcast Australia is a firm believer that the more power used, the greater the scope for energy savings.

To put this belief into practice—and in the spirit of World Environment Day, celebrated annually on 5 June—we have conducted a series of energy audits across our sites nationwide. As part of our ongoing energy efficiency opportunities program, the aim of these audits is to identify areas in which our carbon footprint can be progressively reduced.

A key figure in these audits is retired broadcast engineer, Jacob Vanderstok. He has been employed to assist Broadcast Australia with our greenhouse reporting requirements, and to champion initiatives to improve energy performance.

Jacob identified the DTV cooling systems as an area where energy could be saved. These systems, common to all digital transmission sites, typically employ NEC heat exchange (Hex) units, which are designed to run continuously.

Power-saving potential

Under less-than-extreme conditions, Jacob believed that one or more of the Hex cooling fans could be turned off without compromising cooling performance. With most transmitters using a bank of eight fans, and with each fan consuming 600W of power, there is considerable scope here for energy savings to be achieved.

Based on this premise, Jacob set about devising a solution to bring the fans online only when needed. A temperature controller was designed to implement a three-stage fan control strategy.

Under this system, Fan 1 remains permanently on, with Fans 2 to 7 coming on in stages, as required. Fan 8 remains on standby as the emergency overheat fan, controlled by the original cooling-system thermostat.

A greener future

The system has been designed for easy installation, and this can be achieved without interruption to service. It is currently undergoing trials at Black Mountain Tower (Canberra) and Mount Lofty (Adelaide) sites.

While too early to comment on the performance at Mount Lofty, results from Black Mountain Tower are extremely encouraging. Preliminary findings conservatively estimate potential savings up to 40MWh per year for each broadcast service.

Once the trial period is completed—scheduled for mid-2010—a further 60 units will be built for installation at transmitter sites across Australia, used by the national broadcasters. These are expected to give a payback period of under one year, and deliver a total reduction in our carbon footprint of over 1,000 tonnes of carbon dioxide a year. World Environment Day may be just one day, but these savings represent real ongoing reductions in our environmental impact for the future.

Picture caption:  A new temperature controller for DTV cooling systems permits energy savings to be made

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