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Author Topic: snowed in, again  (Read 420 times)

ajaffa1

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Re: snowed in, again
« Reply #15 on: January 18, 2019, 08:13:44 AM »
Absolutely right Glort, the power companies are rorting the system. They have no interest in generating electricity to support the people and industry of Australia. The capitalist system is all about maximizing profits and shareholders dividends, it has nothing to do with investing in the nations future. I wonder what percentage of the shareholders are Australian and actually live here. I suspect that most of the shares are owned by overseas investment funds that don`t give a sh1t about Australia.

Until the government can put in place some sort of long term energy plan things will only get worse. It is farcical that a country whose economy is based around mining fossil fuels and minerals for export, is afraid of using them to benefit our own population.

We are not the only country with this problem, take a look at this: https://www.dailymail.co.uk/debate/article-6605473/As-Japanese-firm-Hiatchi-scraps-20bn-nuclear-power-plant-ALEX-BRUMMER-says-need-fast.html

Bob

glort

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Re: snowed in, again
« Reply #16 on: January 18, 2019, 11:11:23 AM »

I think you are doing the smartest thing possible Bob, setting yourself up to go offgrid.  I'm going to put some more effort and Dollars into that this year myself. I think it will  be a while off before we need it ( but not that far away) and once you do need it cost and availability will head in distinctly different directions.

I saw today Wholesale prices of $380 for NSW and this afternoon a massive $880 Mw in Tasmania. That is just unbelievable. Look back even 10 years and the average price was 26 bux!

I also see the Energy Market Operator is quietly pumping out rather frantic calls and warnings to it's members to take into account what is at this stage predicted to be a nation wide heat wave on the 24th and allow for the effect on their equipment and the likely increase in demand nation wide.

If the weather Prediction comes to fruition ( and even the weather forecasters stuff up sometimes and get it right)  There are going to be a LOT of lights not on in a lot of places.
The predicted shortfalls are considerable and they are all based on equipment NOT going down. That is not only unlikely, it's bloody stupid to think none of the aged equipment the grid is built on is going to stand up to extreme stress with no failures or problems.

Even in the perfect case scenario, the shortfall will be significant. Have a few minor or one major generation source fall over and the effect is likely to be cascading and very widespread.
 Maybe We'll be lucky and half the country will go down and create a ship storm the  political parties won't be able to escape and put some heads on chopping blocks and a dose of reality in to the situation.

It really is no exaggeration or idle whining to say the quality of our Gubbermints around the world is getting constantly worse and on a downhill spiral.

oldgoat

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Re: snowed in, again
« Reply #17 on: January 18, 2019, 01:16:48 PM »
I don't know where the figure of 40000 litres an hour came from they must be enormous diesels. Even the 70,000 hp diesels in the panamax containerships only use about 10 tons an hour (12000 litres).  Might be a bit of an exaggeration or really inefficient diesel or gas turbines.

glort

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Re: snowed in, again
« Reply #18 on: January 18, 2019, 08:09:47 PM »
I don't know where the figure of 40000 litres an hour came from they must be enormous diesels. Might be a bit of an exaggeration or really inefficient diesel or gas turbines.

Quote
At full tilt, the engines would burn at most 80,000 litres of diesel per hour, however those endlessly quoting the figure (looking at you Josh Frydenberg, Craig Kelly and Chris Kenny!) won’t tell you that they’ve used less than 47kL for the summer so far.

They are diesel Fed LM2500 Turbines.
The above quote is obviously an attempt to justify the consumption which is a real figure they do burn. They are supposed to be backup only but none the less, That is what they suck down when they are lit.  There are 9 of them in total but I believe the figure quoted is for 7 of them running only like would be done to allow for maintence and to have backup..... for the backups in this case. 

What is also rarely mentioned is the fall off these things have above 30oC which is exactly when they would be most likley to be fired up.... to cope with hot weather demand. Once the temp gets to 40 and above, they are starting to loose significant efficiency. They are in fact an air expansion engine and when the air is already partially expanded... Bit different to when you have the things at 30,000ft and the air is - 30o C.

I really think at least one of these things should be fitted with an afterburner.
Yes it ill increase consumption significantly more and No, it won't allow the to make any more power but with an AB at full noise we could feed the useless politicians right in between the engine and the AB and the only emissions then would be a small amount of fine, completely inert ash.

Now that would be great value for money in a toxic waste disposal system in anyone's book and improve the value of this asset to the state and country 1000 fold.

At least!

ajaffa1

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Re: snowed in, again
« Reply #19 on: January 18, 2019, 09:43:09 PM »
Someone needs to build a generator that runs on BS, the stream of effluent coming out of Canberra would power the nation for years.

I worry about your prediction for cascading power failures, I`m OK cos I can fall back on R A Lister. The old, young and sick don`t have that luxury and many could die from heat stroke. The inevitable political fallout won`t achieve anything, they will all just point the finger at someone else as usual. Eventually they will conclude that it`s the peoples fault for using too much power.

Bob

carlb23

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Re: snowed in, again
« Reply #20 on: January 20, 2019, 01:53:03 PM »

 Western Sydney forecast to hit 48 today, that`s going to need a lot of AC to cool down.

I can't see that anywhere but i hope not.
48 is the most I have ever been in in my life, Twice, and it's no fun.

Problem there is when it gets over about 35, most AC starts falling off it's curve pretty rapidly. So do solar panels well before that.

I have a hose on the back of the AC condenser with some garden water mist Nozzles that throw bit of a fog into the coils and cools the intake air.  Makes a HUGE difference to the exhaust air, goes from distinctly hot like a fan heater to quite warm but maybe 20o or more drop.
Allows the machine to do it's job and also not trip out on heat overload.  Nozzles use like .5L water an hour so well worth the benefit.

Nice and cool in here so far and haven't even touched the air.  Will warm up from now on as the sun hits the back of the house.  I'm definitely thinking of getting some shade cloth and clamping it to the gutter all along the exposed back of the house. I think that would make a very big difference to keeping the place cooler.

Of course Mrs would go into orbit about that like every other thing that upsets the look of the place despite the benefit.

I have done my bit for the wildlife this morning.  Got the birdbath I found in the over grown Bushes and put it right next to the grevillia all the native birds are at all day and I can watch from my window.
Might take them a bit to get used to it but if it gets warm enough i'm sure they will soon put their concerns aside for a splash and a drink.  Dad has one and refills it 4 times a day in the hot weather. they know where to find it and make the most of it so hopefully will do the same here.

I suspect in a few short years your  condenser coils will be covered in minerals from the water and become much less efficient  as the air flow becomes restricted and the coils are insulated from the mineral deposits. The coils will begin to corrode in the same time period.   I would not put city or well water over the condenser coils.

I just purchased a new heat pump condenser that i will be installing in april.  It a Bosch Bova 5 ton unit with a seer of 18.  its uses a fully modulating inverter driven Mitsubishi compressor and inverter board with bosch coding.  It only draws about 2 amps on startup and then ramps up via a 85 step program as needed based on load.  It can modulate anywhere from 25% to 110% of its 5 ton capacity. It doesn't use any complicated wiring to control the modulation it sets compressor output based or suction line temperature at the condenser.  it is designed for long low power consumption runs as opposed to a lot of start stops.  with a multi stage stat and variable  speed blower you can get as many or as little BTUs as needed based on outside temps. it can perform anywhere between 1.25 to 5.5 tons depending on load.

They also make a smaller 3 ton model.


I expect with its very soft start amp draw it will be very load friendly.

BruceM

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Re: snowed in, again
« Reply #21 on: January 20, 2019, 04:51:07 PM »
These electronically controlled, variable speed motor systems for home A/C and heat pump systems are technically brilliant except for one thing.  They generate massive home power EMI, as bad or worse than typical grid tie inverters.  Bad enough that the power of neighbors sharing your transformer are also affected. A quick check with an AM radio (of the tuner type with static between stations) near home wiring will show that the AM band may be obliterated by the inverter drive and/or GTI.

 It does not have to be this way.  TI has some new Mosfet gate drive components to help control this problem of variable speed drives, by intentionally reducing power slew rates and high frequency gate currents.  Likewise, more and more Mosfets are being fully characterized for linear and semi-linear operation so that better designers, skilled in EMC, can use them more skillfully to control emissions at the source, by slowing down switching speeds.  This does have a modest affect on efficiency and increases heat sinking requirements, and may also best require some redesign for slower switching frequency and the increase the size some power inductors, of so you can understand why marketing pressures would limit it's application. All consumers know about is price, efficiency, and reliability.  In industrial situations, variable speed motor controls are affecting other control electronics so badly that TI (Texas Instruments) felt there was a market for special integrated gate drive components specifically to address the EMI problem at the source.

The independent science showing that EMI and intentional radio/microwaves affects our biology is being ignored thanks to half a billion $ of power co. cigarette science by the EPRI.   Short term profits and reduced liability triumphs over public health, again. Andrew Marino's "Going Somewhere: Truth about a life in Science" explains who we got here.  https://andrewamarino.com/goingsomewherebook/health.html

A passive filter consisting of a couple stages of toroidal common mode chokes and some small differential capacitors can substantially reduce the EMI generated by these variable speed motor controllers and help keep it off of home power.  On a grid tie inverter they should be on both AC and PV sides of the inverter so that the PV wiring doesn't radiate EMI so badly.  PV with microinverters or buck/boost regulators  on each panel make it more difficult to control PV side EMI, since instead of clean DC from the panels, you now have distributed EMI sources at every panel and every panel will need filtering. 









BruceM

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Re: snowed in, again
« Reply #22 on: January 21, 2019, 02:18:40 AM »
Nice weather today, just a bit overcast and high 50Fs.  So I decided to get my backup PV regulator board put together.  I did that, and bench tested it. 

It's a low side linear regulator that takes an analog optical isolator input of 0-5 ma for 0-15 amps charge current. The battery bank controller computes that signal via micropower analog op amp math. The PV linear regulator is powered by 7 ma of nominal +24V from the lowest 24V panel in the 5 panel string.  It was designed for a nominal 120V (220V peak no load) PV array but now that I've changed to 500V linear mosfets, it could do a 230VDC system at half the current.  Mosfets as linear devices are pretty sweet compared to power Darlington Bipolars, there is no base current (called gate for Mosfets) to control them, just gate voltage of around 4 to 10 volts.  Each transistor carries 1/7th of the total demanded current.

The PV regulator is a tight squeeze on the experimenter's bargain board size at ExpressPCB.  On the back you see the solid 14 gauge "jumpers" for power distribution.  For the new build I updated the two quad operational amplifiers  to some newer ultra low offset bias, rail to rail input and output types.  The analog world just keeps getting better.  To use MOSFETs as linear devices in parallel, you must use an op amp for each MOSFET, just as for Darlington transistors.  A 0.1 ohm, 3W shunt resistor for each transistor's output allows current sensing for each.  The op amp drives the gate voltage just enough to get the desired current at the shunt resistor. The world runs on OP amps.

This board gets mounted on a 36"x12"x 5 inch deep finned aluminum heat sink as I don't care for fan motors. 

I do miss out on about 17% power gain of very cold mornings; the linear regulator must piss away the excess voltage on very cold days, unlike a switching buck converter.  It's not all loss, it does help warm up the closed up battery bank shed in the winter.

I am not seriously tempted to do a low frequency, low EMI buck converter version just yet, but I have thought about that design after my success with the inverter project. 
Linear is simple, and I like that.