Discussion: Design temperatures

George Town may well be 33 degrees. The design ambient for Melbourne air conditioner design is 35 degrees. This is fine for humans who can tolerate the higher temperatures if the set temperature is raised on the previously rare occasions when the ambient is above 35. But computers and Connex drivers don't fall into that category as they require a relatively low temperature to function. I first met this issue back in the seventies when dealing with an irate I/T manager who didn't understand why his air conditioning (which he had purchased) couldn't cope on hot days.

Just try finding the extra $1M to spend on your electricity network that will make everyone else on the planet millionaires & you will understand one reason why the design specs are so low.

Another reason may be that the people they bought the technology from didn't understand our climate.

I have had Europeans come back to me telling me that some of our system parameters are an order of magnitude out when they were just an order of magnitude outside their understanding of "normal".

And finally - the electricity system is only intended to be reliable for a 1 in 10 year event. Most politicians and business lobbyists believe that 1:10 is an extremely rare occurrence(???) and so are unwilling to provide adequate funds to do anything more.

Call the investment recession busting infrastructure and you'll get your million extra!

You shouldn't read the Advertiser, it will rot your brain. I used to be a lot smarter :)

As much logic in the Addy argument as their take on the lower Murray lakes.

Weird ..I have been at Lagoon beach between Low Head and George Town on a day that felt way hotter than 29 degrees, well I guess Low Head is exposed to winds from just about every direction. . We used to have a rule at high school in Tasmania, when it hit 35 degrees everybody could go home. No air conditioning in schools. I guess they never really thought it would reach those temperatures.

The interesting thing I find with this one is that it doesn't seem to me like a case of a decision to save money by accepting a lower level of reliability (something which I think is at play with, say, the rail system), as there is a strong commercial incentive for the system to function during the most extreme events - it's during them that there are extreme amounts of money to be made.

From an engineering designer perspective it is perfectly logical to not design for the worst case if the risk assessment is appropriate. The cost / equipment size / operating cost is so much greater for a design at 40 degrees cf a design at 35 degrees. There was no air conditioning in my high school and if we had closed when the temperature in the classroom was > 35 we would have had very long summer holidays. North walls in the modern classroome were glass panels. Design by some Melbourne architect??? They have a lot to answer for. I can remember my exercise books being sodden with perspiration and unusable.

The simple truth is that at some time past the committee for setting standards has looked at the historical data and decreed that 95% of January Melbourne's summer max is < 35. Therefore the design figure is 35.
Or some similar logic - don't hold me to these numbers!

I think you are attributing far too much logic to the decision making. There are two more likely and plausible explinations. The first is that when "shopping around" they were offered a standard unit rated at 33 for significantly less than one with a higher rating, and they just changed the specs to save money. The secong is that it was just a stuff-up. As the old saying goes "Given the choice between a stuff-up and a conspiracy, go with the stuff-up every time."

I'm actually a bit perplexed as to why the thing had to shut off rather than run at a reduced rating once the temperature exceeded design specs. We had something similar happen here where the literature on a piece of equipment showed a slow ramp down above a certain level, but the implementers had just gone for the simple switch-off. Plant similar to ours had been in operation in Europe for years, but never exceeded the design conditions & so no-one had ever come across the problem. 2 weeks in service in Australia and we ran into trouble...

As for the market - I don't know Basslink well, but as far as I understand, on dispatch they are paid at a rate related to the differential between the Tasmanian and Victorian regional prices. In a situation where temperatures are high in both regions, then it would be reasonable to assume that prices are going to be high in both regions and so there is little incentive pay for the capability to be dispatched in these circumstances.

There was a fair degree of concern when the Basslink project was undertaken that Victoria could syphon off lots of cheap Tassie hydro when it suited them, drain their capacity then sell back to Tassie at inflated prices. This was just after NZ got itself into trouble by dispatching a lot of cheap hydro, running into drought conditions & then needing to rely on very expensive alternatives to get them through. The gas generators had used their market power without the almighty market understanding what was coming next . So, good old conspiracy theory between states is alive & well :)

So what we need is a national grid, run by a non-profit-making organisation (the federal government)?