Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


Filter this topic showing only the reply marked as answer View this topic in a long page with up to 500 replies per page Create new topic
1 | ... | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | ... | 125
14288 posts

Uber Geek
+1 received by user: 2590

Trusted
Subscriber

  Reply # 1481130 29-Jan-2016 11:37
Send private message quote this post

fortydayweekend:

 

 

 

A small battery (10kWh) might even make sense soon - if you're still using 10kWh of power in the winter evenings, you could avoid 10 * $0.12 = $1.20 of lines charges each day by charging the battery at the offpeak rate and using it during the peaks.

 

 

Maybe. I just looked at a random winters evening, we used 13kwh of power at around 13c/kwh, though some was lower at 10c/kwh. Overnight rates were 8c/kwh. Battery and inverter technology will probably have to get a lot cheaper before that narrow margin makes sense. Install costs could be expensive too It may make more sense when power prices are higher, later summer when the lakes are dry.

 

Heat pump driven night store may make sense, but that takes a lot of thermal mass to be worthwhile.





AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer


35 posts

Geek
+1 received by user: 4


  Reply # 1481134 29-Jan-2016 11:45
Send private message quote this post

timmmay:

 

fortydayweekend:

 

 

 

A small battery (10kWh) might even make sense soon - if you're still using 10kWh of power in the winter evenings, you could avoid 10 * $0.12 = $1.20 of lines charges each day by charging the battery at the offpeak rate and using it during the peaks.

 

 

Maybe. I just looked at a random winters evening, we used 13kwh of power at around 13c/kwh, though some was lower at 10c/kwh. Overnight rates were 8c/kwh. Battery and inverter technology will probably have to get a lot cheaper before that narrow margin makes sense. Install costs could be expensive too It may make more sense when power prices are higher, later summer when the lakes are dry.

 

Heat pump driven night store may make sense, but that takes a lot of thermal mass to be worthwhile.

 

 

 

 

Interesting, the Wellington lines co just gives a discount rate for 11pm - 7am power, which Flick is passing on to you. The differential isn't nearly as much as in Auckland - between 3c-9c. It'd take a lot more to make a battery worthwhile then.

 

You could also pump water into a rooftop tank at night and run it through a micro-hydro turbine during the day :)


 
 
 
 


4 posts

Wannabe Geek


  Reply # 1481227 29-Jan-2016 13:55
Send private message quote this post

fortydayweekend:

 

timmmay:

 

fortydayweekend:

 

 

 

A small battery (10kWh) might even make sense soon - if you're still using 10kWh of power in the winter evenings, you could avoid 10 * $0.12 = $1.20 of lines charges each day by charging the battery at the offpeak rate and using it during the peaks.

 

 

Maybe. I just looked at a random winters evening, we used 13kwh of power at around 13c/kwh, though some was lower at 10c/kwh. Overnight rates were 8c/kwh. Battery and inverter technology will probably have to get a lot cheaper before that narrow margin makes sense. Install costs could be expensive too It may make more sense when power prices are higher, later summer when the lakes are dry.

 

Heat pump driven night store may make sense, but that takes a lot of thermal mass to be worthwhile.

 

 

 

 

Interesting, the Wellington lines co just gives a discount rate for 11pm - 7am power, which Flick is passing on to you. The differential isn't nearly as much as in Auckland - between 3c-9c. It'd take a lot more to make a battery worthwhile then.

 

You could also pump water into a rooftop tank at night and run it through a micro-hydro turbine during the day :)

 

 

Interestingly I looked at some of these options. Batteries are too expensive for my requirement but I thought the pump / turbine may be possible until I calculated I would need an Olympic sized swimming pool 3 meters off the ground of my property.

 

This is an interesting article on the different options although his requirements where much larger.

 

http://physics.ucsd.edu/do-the-math/2011/09/got-storage-how-hard-can-it-be/


14288 posts

Uber Geek
+1 received by user: 2590

Trusted
Subscriber

  Reply # 1486437 6-Feb-2016 12:35
Send private message quote this post

I've done some calculations this morning to work out how much I'd save if I had water heating only between 2 and 4am. This meets the requirements to heat to some given temperature at least weekly to prevent legionaries disease.

 

I've based it around these assumptions, with a couple of notes:

 

  • 80% of the power used in the 60 minutes that we get up is hot water. This seems reasonable as we have efficient lighting and don't use much heating at that time - if we heat in the winter it's before we get up. Towel rail runs after this period, but underfloor heating is running.
  • I can't estimate evening hot water usage, so I use the morning usage, but I take 95% instead of 80%. This is because we wash the large dishes by hand every evening.
  • We're two adults, and we shower 6am - 6:30am in the morning, and randomly in the evening. There's also an occasional bath which I haven't taken into account.
  • I haven't taken into account the random bits of heating to keep the cylinder warm during the day. This probably adds to the savings.

 

 

The data came from:

 

  • Flick sent me my usage for 5 months May to September a while back, when I asked them to
  • Geoff from Nodewatch sent me my node's usage over a period of years. You can download pricing history by month here, but he'd already done it for my node so I used his data (I checked a few points and it as accurate).
  • I wrote a couple of little Java programs to parse the long form data. Excel could probably have done it, but the formula would've been a PITA to write.

 

 

My working is available on Google Drive:

 

  • This document works out how much money I think we'd save based on our actual usage from Flick, May to Sept 2015. This suggests savings of $139/year, though I note that I have no data for summer, and I think prices are highest at the end of summer.
  • This document estimates how much we'd save over the 2009 - 2015 period, based on estimated power usage. This comes out at $175 to $210 per year.


I've recently gotten an estimate to fit a timer, a heavy duty relay, and labor to fit a timer, around $400 inc GST. This suggests a payback period of around two years.





AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer




730 posts

Ultimate Geek
+1 received by user: 13


  Reply # 1486679 6-Feb-2016 21:46
Send private message quote this post

The cost for me was $378 for a EZYswitch (SMS controller), $34+gst for a 12VDC relay on my switchboard, and 30 mins of electrician labour ( he was here doing other stuff ).  I already had a spare sim card.

 

Phone is programmed to send a text at 5 am to turn hot water on for 2 hours.  And if it's cold during the day, I can send a text to turn water on for an hour if I want a hot shower in the evening.

 

It was useful initially for it to sms me back with acknowledgements but since it all works I let the sim card balance expire so it can't send me texts, but it can still receive my commands.

 

But I also gain another port on the EZYSwitch to control another device or monitor something else.

 

I should do the analysis to see what my payback period is as well.  But it's a little tricky since although I might turn the power to the cylinder on for 2 hours, it may only need 1 hour until it switches off due to the internal thermal regulator.


21621 posts

Uber Geek
+1 received by user: 4432

Trusted
Subscriber

  Reply # 1486699 6-Feb-2016 23:05
Send private message quote this post

Ouch. I was just going to get a contactor put on it with a plug to put into a wemo.





Richard rich.ms

497 posts

Ultimate Geek
+1 received by user: 19


  Reply # 1486728 7-Feb-2016 00:18
Send private message quote this post

richms:

Ouch. I was just going to get a contactor put on it with a plug to put into a wemo.



If you get a Wemo from the UK it's rated at over 3kw too. Then with Nodewatch and IFTTT you can control it based on the current spot price. Once it goes below a certain spot price let it turn on, and then when it's goes above a higher spot price you can get it to turn off automatically.

21621 posts

Uber Geek
+1 received by user: 4432

Trusted
Subscriber

  Reply # 1486730 7-Feb-2016 00:32
Send private message quote this post

I wouldn't trust the silly little relays they put in the things with constantly switching 13 amps in any case.

 

Mine will be timed so that it runs when the sun is out, because I am not going to bother with a complete solar diverter system just yet as there is going to be very little spare power during the day.





Richard rich.ms

14288 posts

Uber Geek
+1 received by user: 2590

Trusted
Subscriber

  Reply # 1486746 7-Feb-2016 07:13
Send private message quote this post

Text control sounds like a pain in the butt to me. I'll put in a regular timer. I'll not even put in a bypass switch, but I'll do that when we redo the switchboard whenever that is. We still have fuse wire for a couple of circuits...





AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer


57 posts

Master Geek
+1 received by user: 8
Inactive user


  Reply # 1486938 7-Feb-2016 13:12
Send private message quote this post

Brand new to Geekzone, and a recent Flick convert, haven't even got the first bill yet. I installed a hot water timer switch a week ago, and it's working out well according to the Flick web portal graphs.

My question is regarding Nodewatch however - is there a reference somewhere to correlate street address to the relevant node code? (Porirua/Titahi Bay in case anyone knows it off the top of their head).






35 posts

Geek
+1 received by user: 4


  Reply # 1486947 7-Feb-2016 13:21
Send private message quote this post

TKR0331 for Titahi Bay I think

14288 posts

Uber Geek
+1 received by user: 2590

Trusted
Subscriber

  Reply # 1486958 7-Feb-2016 13:55
Send private message quote this post

That's the node I have in Johnsonville, so even if it's not perfect it'll be pretty close. No idea how to look them up.

 

Tony, what's your % saving compared with your old company, according to Flick? It might not tell you yet. We're at 18% this period and 22% overall, with minimal behaviour modifications - we run washing and drying off peak if we can, and the dishwasher runs at 3am. In winter we put the heating on earlier than we otherwise would, to avoid the evening peak, but there's not much you can do about needing heating during the evening in winter.





AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer


57 posts

Master Geek
+1 received by user: 8
Inactive user


  Reply # 1486973 7-Feb-2016 14:14
Send private message quote this post

Thanks for that - big help. I don't think flick will tell me, as I came from Powershop so it's a bit hard for them given the variability. I recall the signup blurb saying something about comparing to the majority retailer instead. My trade me sourced hot water timer cost me $25 including installation (which luckily was free). That and using the dishwasher delay button is the sum total of my changes so far.

As a matter of interest, where have you set the Nodewatch threshold, and can you change easily it if it starts to spam you? Nodewatch didn't ask me to login when I peeked into the site today. What frequency emails does that generate? I guess I only want to know if the price goes OTT.

14288 posts

Uber Geek
+1 received by user: 2590

Trusted
Subscriber

  Reply # 1486984 7-Feb-2016 14:38
Send private message quote this post

Electrician quoted me $400 for a hot water timer, details here. Summary: even $100 timers will burn out because of the high regular load, care is required.

 

Yes you can change Nodewatch thresholds easily. My threshold is 14c/kwh (plus some at higher numbers), I think I've gotten a half dozen emails in the past 3-4 months. In winter they're a lot more regular, as power prices vary a lot more. 14c/kwh plus line charges and GST is about what most people pay all the time in Wellington.





AWS Certified Solution Architect Professional, Sysop Administrator Associate, and Developer Associate
TOGAF certified enterprise architect
Professional photographer


57 posts

Master Geek
+1 received by user: 8
Inactive user


  Reply # 1486999 7-Feb-2016 15:01
Send private message quote this post

I guess time will tell about how long it lasts. Rated for 25amps so it has a bit of headroom. I was surprised it actually had a real contact, I was expecting a SSR actually.
Scope to fine tune its running period yet, although the price at night appears quite consistent between 12 and just after 6 looking at the graphs. Early days, but I suspect it only needs a couple of hours or less running in normal circumstances. I have it set to on between 0030 and 0600 at the moment.


1 | ... | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | ... | 125
Filter this topic showing only the reply marked as answer View this topic in a long page with up to 500 replies per page Create new topic



Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Geekzone Live »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.