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SILICON SILIC CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Editor Nicholas Vinen Technical Editor John Clarke, B.E.(Elec.) Technical Staff Ross Tester Jim Rowe, B.A., B.Sc Bao Smith, B.Sc Photography Ross Tester Reader Services Ann Morris Advertising Enquiries Glyn Smith Phone (02) 9939 3295 Mobile 0431 792 293 glyn<at>siliconchip.com.au Regular Contributors Brendan Akhurst David Maddison B.App.Sc. (Hons 1), PhD, Grad.Dip.Entr.Innov. Kevin Poulter Dave Thompson SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490. All material is copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing and Distribution: Derby Street, Silverwater, NSW 2148. Subscription rates: $105.00 per year in Australia. For overseas rates, see our website or the subscriptions page in this issue. Editorial office: Unit 1 (up ramp), 234 Harbord Rd, Brookvale, NSW 2100. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9939 3295. E-mail: silicon<at>siliconchip.com.au ISSN 1030-2662 Recommended & maximum price only. 2  Silicon Chip Publisher’s Letter Big Brother can control your aircon Australians love air-conditioning. Over the last few years, more and more domestic aircons have been installed, to the point where market penetration is now approaching 70% or more in some cities. And why not, Australia has hot summers and if people want and can afford air-conditioning, then there is no particular reason why they shouldn’t have it. In fact, most Australian cities have just sweltered through a very hot Summer and it can be particularly difficult to get to sleep on hot, humid nights. As someone who does not have air-conditioning at home, I can testify to that. That has made me consider having air-conditioning installed so that we can be more comfortable next summer. But in thinking along these lines, I and millions of other Australians are contributing to an ever-increasing peak demand for electricity in those very hot summer periods and our diminishing grid cannot cope, especially with the trend to renewable energy sources which often do not contribute when they are most needed. For example, if a large high pressure system is stationary over the southern states, as can happen in the hottest summer weeks, there may be very little wind power generation. And solar panels drop their power output just when the evening peak demand is ramping up. Ultimately, if there is insufficient grid capacity, the AEMO (Australian Energy Market Operator) can demand load shedding which means that consumers get blackouts. Great. So there you are, enjoying your hard-earned air-conditioning and all the other benefits of a modern economy and the electricity goes off and you don’t know how long the blackout might last. This is set to happen much more frequently in South Australia but other states will not be immune. In their “wisdom”, the authorities have come up with another scheme to control peak domestic demand and it is called, ironically, a DRED or Demand Response Enable Device. It is a system to switch off or reduce the output of your aircon and is described in this month’s issue by Dr David Maddison. DRED-compatible aircons can have three Demand Response Modes, referred to as DRM1, DRM2 & DRM3. DRM1 completely switches off the compressor while leaving the fan running so without warning you will be left sweltering and wondering if your aircon has failed. DRM2 and DRM3 are modes which reduce the compressor’s output and depending on how hot it is outside, you may not notice much change. Virtually all aircons now being sold in Australia are DRM-compatible but most will require an additional module to be installed by the electricity retailer to enable it to be controllable. Some energy retailers are actively encouraging consumers to opt-in to DRED schemes with non-threatening slogans such as CoolSaver or PeakSmart and with one-off incentive payments. But don’t opt in; not if you know what’s good for you! The incentive payment (typically a maximum of $400) is simply inadequate. It means that when you really want air-conditioning, it could be switched off. Worse still, if you have a grid-connected solar panel system, you could be subjected to the bitter irony of having your solar panels feeding the grid with power while you are deprived of air-conditioning. How happy would you be? Right now, DRED is not compulsory but if Australia’s grid becomes more crippled by having to accept more renewable energy input at the expense of good old reliable coal-fired base load power stations, you can bet that DRED will become compulsory for everyone who owns a compatible aircon. Mind you, some technically savvy consumers might then decide to take matters into their own hands and figure out a way to disable DRED. Who could blame them? Leo Simpson siliconchip.com.au