Thanks for that Moz. According to that we should have the panel at 33 degrees for maximum annual solar input with a fixed panel. But as you say that is not what we should be trying to maximise. What we want is sufficient hot water all summer, extended as far as we can for spring and autumn. Based on when we currently turn the power supply on (May to October) it appears that we need about 5kwh/m2/day, so setting to the winter tilt angle won't give us sufficient heating all summer. So, eye-balling the Adjusting the tilt four times a year table, probably 45 degrees would maximise electricity savings.
However, this may be overly simplistic, as the turning on of the power booster is usually the result of 4 cloudy days in a row, which will occur much more often in the seasons other than summer.
Especially for people who are switching from off peak resistive systems to on-peak boost (as in Australia and very probably NZ) because the boost cuts in in the evening when it’s clear the solar has not got the water hot enough.
We don't have peak and off-peak power charges, and the booster is not timed, so as we mainly shower in the morning, the booster will heat the cold water being added to the tank, which would be unnecessary on a sunny day, as the sun itself can achieve it by the end of the day.
But better to spend a little bit more than to suffer luke-warm showers in the colder months.
When we had our solar hot water installed (an Edwards LX305 in 2004), I asked about increasing the angle of the panels, and was shown a convincing graph of the efficiency based on angle, and basically the efficiency does not fall off all that rapidly. Basically, if your panel is facing within 30degrees of north, and is tilted between 15 and 50 degrees you'll be getting over 95% of the optimal annual solar input for a fixed panel.
Our return on investment calculation at the time, was that the system would never pay for itself (we'd make more money by investing the funds, and paying more for our electricity). We installed it anyway because we felt it was a good thing to do. As it turns out, investment returns have dropped, and electricity prices have increased, so it was probably a good investment. We turn the mains feed to the cylinder off at the start of November, and turn it back on at the end of April, so basically have free hot water all summer. Of course it is still helping the rest of the year, so our power bill is less than similar families (2 teenage children). We use 14kw/day around this time of year (electric blankets and heaters), and about 8kw/day in summer (really should get a more efficient fridge).
When our dishwasher was installed, I asked for the plumber to connect the hot pipe to it, but he refused, saying it would invalidate the warranty. Of course the dish-washer is out of warranty now, but I don't think the $200 (or more) it'd cost to get it changed over now would be recouped, but it does annoy me that we have to unnecessarily heat water to run it in summer.
If everyone did then we could solve practically all of society’s problems.
… surely the Chinese block travelling thousands of kilometres to market whilst remaining frozen also increases its total emissions
Yes, of course. But as David keeps re-iterating in his comments, the details of the ice-block are irrelevant. The ice-block is merely an example, to show how taxing carbon for goods manufactured in NZ will send the wrong price signal to the market, so it would favour the worse outcome for the world.
Edit: I'd just like to re-assure you, David, that at least one person out here understands what you did, and is pleased to have been educated on why taxing carbon is a tricky problem.
How can a so-called newspaper get its “facts” so blatantly wrong :
BP and Caltex continue to offer supermarket docket discounts through Progressive Enterprises,…
It’s Z and Gull at the moment, but Z only until the end of the month, which, bizarrely, is what the rest of the article is about.
Update: Oh okay. Stuff explains it better :
However, Countdown customers with fuel dockets issued after that date will still be able to redeem them at BP and Caltex, through a partnership with AA's Smartfuel programme.
Surely you mean "Petal B".
Stuff stuffs up in a mega-way ...
New Zealand-based Kim, meanwhile, is in a protracted legal battle with the United States Department of Justice, which accuses him of criminal copyright infringement through his now from his defuncted Megalupload file hosting service.
Pfft, spell-checkers, who needs 'em when you can stuff up grammar so easily.
The pinged drivers should start suing Uber. Uber promised to "stand by them 100%" but have not. That's a breach of contract right there.
To get an idea of the Norwegian sense of humour I recommend watching the "Made in Mosjøen" web series.
With the Saudi disdain for Human Rights, and Uber's disdain for law, it looks like there is some synergy there for creating Evil MegaCorp Inc.