Switching geyser off?

Wiring, circuits, batteries etc.

Re: Switching geyser off?

Postby Greystoke on Mon Jul 20, 2009 8:33 am

windgat wrote::lol: Where do you find all these icons!?
I borrow them from another forum (tropical fishkeeping: http://forums.tfhmagazine.com/index.php) Don't worry, I asked permission :D
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Re: Switching geyser off?

Postby Greystoke on Tue Aug 04, 2009 2:08 pm

I've checked the power usage between switching the geyser OFF between bathtimes, except for time to heat-up the water befor the next use (about 4 hrs), and leaving the geyser ON 24/7.
I have found the difference between the two minimal. Infact, the kWhr usage overlapped in some case. (see graph)

Image
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Re: Switching geyser off?

Postby windgat on Tue Aug 04, 2009 4:59 pm

Sounds interesting... or would be if I could understand your graph! How about some axis labels? And explaining what that table is at the bottom.

4 hours before is a very long time. I think most saving may happen if you turn geyser OFF around midday (enough heat for rest of day), then on about half an hour before first morning use. Could you try something like that?
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Re: Switching geyser off?

Postby Greystoke on Tue Aug 04, 2009 5:53 pm

OK,OK,

It's a distribution graph. It records the number of instances(occurrences) for a specific range of values.
So, . . . there is one occurence at less than 5kWhr, then there are 5 occurrences between 5 and 6 kWhrs, followed by 3 "On" occurences between 6 and 7 kWhrs, etc ...etc

4 hrs isn't bad. You need arong 2.5 hrs to heat-up the full volume of the geyser, but if someone wants to use the bath early (like 6am) the water isn't hot enough yet.
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Re: Switching geyser off?

Postby windgat on Tue Aug 04, 2009 6:24 pm

I am trying hard, believe it or not, but I STILL don't get the graph. Ok, a distribution graph, I get that, but what is an 'on occurrence'?? And a 'off' one too?
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Re: Switching geyser off?

Postby Greystoke on Tue Aug 04, 2009 6:40 pm

"On" = on 24/7
"Off" = off most of the time, except for some time (4hrs) before the next use.

I've taken readings every 24 hrs, and worked out how many kWhrs were used, either in the "On" position, or in the "Off" position.
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Re: Switching geyser off?

Postby Greystoke on Wed Aug 05, 2009 7:17 am

If you take readings every 24 hrs at the same time, you get a distribution of readings. There should be two distinct distributions, ie: one for when the geyser was "On" all day, and one for when the geyser was "Off" most of the day, and you expect the "On"-distribution to be higher than the "Off"-distribution. Question is: By how much ?

In this instance the difference between the two distribution is about 1kWhrs per day on average, which (at the proposed increased rate) amounts to ±R0.75 per dayImage.
There is also evidence of an overlap between the two distribution. Between 5 - 6 kWhrs and 8 - 9 kWhrs the two distributions completely intermingle, which indicates that the results from month to month could become negligible.


(Sorry for the confusion. Is this better explained ? :wink: )
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Re: Switching geyser off?

Postby windgat on Wed Aug 05, 2009 10:30 am

That's better, even I can understand now! (I thought an 'on event' was the thermostat switching on...)

Now the trick is to find the switching off pattern that maximises the saving.

Secondly, if you force the geyser off during peak hours and on at 10pm or so (as Eskom plans to do for you), will this use slightly more power as I suspect?
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Re: Switching geyser off?

Postby Greystoke on Wed Aug 05, 2009 11:03 am

windgat wrote:Now the trick is to find the switching off pattern that maximises the saving.
I'm not sure if there is an optimum "switching-off" pattern (and if there is, I suspect the effect will be minimal)
The main problem appears to be the random use of the bath: never at the same time (hours apart !), and never the same amount of water (from 50 to 100L !)
It makes "fine-tuning" the "switching-off" pattern very difficult.
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Re: Switching geyser off?

Postby Greystoke on Wed Sep 09, 2009 6:40 am

Right,
I've finally come to a decision.

You can't have a windcharger to power a geyser if you don't have blades that are at least 1.5m long. Easy to work that one out: average windspeed in PE = 3.3m/s; average required output power (enough to maintain the temperature of a 100L geyser) = ± 125 Watt.

So, . . . I've asked a friend - who is a welder - to give me a price to make me a solar panel, according to the attached drawing, to heat-up my geyser.
Attachments
ENERGY in Your Own Back Yard.doc
(66.5 KB) Downloaded 555 times
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Re: Switching geyser off?

Postby windgat on Wed Sep 09, 2009 1:51 pm

Looks good! Let us know how it goes...
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Re: Switching geyser off?

Postby Greystoke on Thu Sep 10, 2009 6:39 am

Oh, I will (in the end) build this wind turbine. It's only off the priority list now.
Did you hear that ESKOM wants an additional tariff increase of 60% in April next year?
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Re: Switching geyser off?

Postby windgat on Fri Sep 11, 2009 12:01 am

I heard 90%...

In order to build new power stations, Es-skom will need dramatic and ongiong tariff increases. They are being quite obstructive to the potential new IPPs, for example w.r.t. the PPA (power purchasing agreement) regulations now being worked out.
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Re: Switching geyser off?

Postby Greystoke on Fri Sep 11, 2009 7:35 am

Oh, I can understand that tarif increases have become necessary. I knew the "old" ESKOM board very well (I was a director of a well-known electric cable making company). They weren't the brightest brains around, but at least they knew how to budget (and strategies). They would build a new powerstation every five years or so, and they invested in new technology.

However, THE PRESENT LOT . . . . . have been sitting on their butts for fifteen years, doing sweet nothing, and getting moerse salaries and bonusses for it. Image
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Re: Switching geyser off?

Postby Bream on Thu Jun 02, 2011 12:12 pm

I ahve been using USB loggers for more than a year and I find it very much practical. It can gather all the data, and yu can later analize it.
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Re: Switching geyser off?

Postby windgat on Thu Jun 02, 2011 6:57 pm

So have you experimented with switching off etc, and have you found anything interesting?
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