Hard News by Russell Brown

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Hard News: Going solar?

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  • Rob Stowell, in reply to Brent Jackson,

    Has anyone else ever connected a hot water feed to the dishwasher ?

    We do, to an ASKO which claims saving up to 75% of the power in the 'enviro' cycle (which uses a water temp of 55 degrees) when you provide hot water to the machine.
    Because we also have a long run from tank to kitchen, and seldom have 55 degree water anyway, the electricity saving will be considerably less on average. Still, solar/wetback hot water is something we can afford to chew through in a way that power isn't, so it works out for us.

    Whakaraupo • Since Nov 2006 • 2110 posts Report Reply

  • Rob Stowell, in reply to Lucy Telfar Barnard,

    a small woodburner for my city life, for aesthetic purposes

    We always wanted on of these 'studio' fires. They look good, but as our architect affirmed (he put one in in his own huge open-plan Queenstown house) just don't put out enough heat for a big space.

    Whakaraupo • Since Nov 2006 • 2110 posts Report Reply

  • Bart Janssen, in reply to Rob Stowell,

    We always wanted on of these ‘studio’ fires.

    If you are just going for looks then this is the fireplace we've always wanted. Of course our little Ahead home really has no place for it :).

    Auckland • Since Nov 2006 • 4460 posts Report Reply

  • Chris Waugh, in reply to Lucy Telfar Barnard,

    According to Norwegian testing standards, it meets our requirements for efficiency and emissions.

    Hmmm... Norway. Lots of forest, lots of wooden buildings, properly cold winters, but those buildings stay warm*. If the woodburner is good enough to keep the Norwegians happy, then how could it possibly be a problem in NZ?

    *I was only there for a summer, but you could tell the houses were built properly in a way NZ houses are not.

    Wellington • Since Jan 2007 • 2401 posts Report Reply

  • Lucy Telfar Barnard,

    I sent off for a brochure for those focus fires, Bart. The cost of them was eye-watering.

    Chris, I agree entirely, though the issue for NZ MfE is mostly about keeping the air clean, with efficiency a by-product of that.

    Still, NS3058/3059 measures aerosol mass using a dilution tunnel. Our New Zealand Standard 7403:1992 (AS4013) uses a similar method, but as recent local Consumer testing has shown, type of wood and testing regime makes a big difference to outputs.

    To add insult to the whole thing, Consumer's test also found that outputs for actual use vary significantly from test outputs - and the manufacturers' need to tweak their models to best meet testing standards, may reduce air quality performance in real conditions. These differences make our refusal to accept other testing systems even more ridiculous.

    Wellington • Since Nov 2006 • 585 posts Report Reply

  • steven crawford, in reply to Bart Janssen,

    They look pretty simple and inexpensive to fabricate. If it only costs around 10 k to have emission tested. We wouldn't need to many interested party's to make it worth while.

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • Lucy Telfar Barnard,

    The trouble is (if it’s the gyrofocus you’re talking about) it’s pretty near impossible to get an open fire to pass emissions tests. I say “pretty near” because I haven’t heard of any that passed, but don’t know enough to say it’d be impossible. Or it could be they don’t pass the efficiency requirement (the other thing required to be on the MfE list)
    If you’re talking about one of the glass-doored models, you might have a better chance. I don’t know how difficult it would be to homebuild a model that would pass the MfE stesting standards, but suspect it might be challenging. The particularly difficult part would be that without your own lab, you couldn’t be confident it would pass the test, and each attempt would cost $10K.
    ETA: I take that all back. Open fires are outside the testing standards, and rules for them vary from council to council. So it you want the gyrofocus, it wouldn't have to pass the testing regime at all - but your local regional council might not allow it anyway.

    Wellington • Since Nov 2006 • 585 posts Report Reply

  • steven crawford,

    Linda really likes the little Dovre vintage that you mentioned, Lucy. And she is suggesting it to one of her friends. It is cute, like you said. That would be a much more difficult stove to build in an engineering workshop.

    Maybe that could be a candidate for a consortium approach. If there is enough interest from New Zealand , the overseas manufacturers might come to the party, and get there burners compliant here.

    But that’s not the point, I know. I am just going build a big wood fire kiln over in the back yard, and I might put salt in it. Thats going to learn them a couple of things, or three.

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • steven crawford,

    Ok, I have my first expression of interest or should I say dissatisfaction with the certified burners available in New Zealand, besides Lucy.

    I am now threatening to become the agent for funky wood burners, and no, I will not be wear my undies on the outside.

    So who would like a funky wood burner?

    If I see some interest here, I will conduct a serios bit of market research. Then we shall think about sticking it to the man, and jumping thru every hoop it takes to bring funky wood burners to the people.

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • steven crawford,

    Update! I have just been talking at Kim Dot Com’s interface. Kim is enthusiastic about throwing his weight at this project. What can I say. Wow, just wow!

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • Hebe, in reply to steven crawford,

    Funky woodburners wood be wonderful. But first you need to get KDC to get the unachievable and inhumane Christchurch pollution targets brought into line with European cities and allow people to instal cleaner burners -- in new builds too.

    Christchurch • Since May 2011 • 2899 posts Report Reply

  • steven crawford, in reply to Hebe,

    I see, I am going to have to talk at lots of peoples people. But eventually, with every one talking at each other, and with Kim Dot Com throwing his weight around, somebody is going to talk back at us. Which will be a start. I’ve got a good feeling about this.

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • Bart Janssen, in reply to steven crawford,

    So who would like a funky wood burner?

    When we finally build "the house", you know the one you dream about building but it's never the right time, a funky wood burner would be on the list of must haves.

    Just one issue, the one we liked from that web site is surely a piece of copyrighted art (rightly so since it is beautiful), so deriving funky designs "in the style of" would be cool/hot but direct copies would be less cool.

    And since we wouldn't be building in CHCH the restrictions would be less draconian ... hmmm Dragon fire, good name no?

    Auckland • Since Nov 2006 • 4460 posts Report Reply

  • steven crawford, in reply to Bart Janssen,

    You on the list, and your concerns are noted. Thankyou!

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • Aidan,

    Bit late, but we've got a 30 tube/250L electrically boosted system. Here in Canberra (more like Christchurch weather, hotter in summer though) we don't need to boost Sept->Apr. We've got a timer switch in the fusebox for the electric boost, and it comes on from 5.00-6.20pm, and it will top it up if we've had a poor solar day.

    We have hard frosts, so the tubes make much more sense here. People on various enviro forums reckon you get a much bigger surface area for panel systems for the same cost, so if frost isn't an issue this is a better way to go. Also the integrated thermosiphon jobs are very well understood, very low tech (I've been quoted $1000 to replace the controller on our system, which is outrageous. I wouldn't pay that, but it gives you an idea of what some are paying). Don't write off flat panel systems, but I don't know enough to recommend any.

    Your water use patterns matter a lot. If you all tend to shower at the same time of day it helps. We scrub the kids in the evening, but the adults are morning showerers. This means the tank is half full of cold water overnight. It is supposed to stratify and not mix too much, but it still has an effect.

    We tilted our tubes up to 50deg, as we have an over-production in summer, but our shoulder and winter production was disappointing. There was a substantial improvement after tilting, with the added bonus of less over-heating and venting in summer. A wetback + solar system would be a great combination, as a solar system sized for summer will struggle in winter. Sized for winter it is likely to be expensive and still struggle on very cold dull days.

    We average about 5kWh/day electricity usage in Summer, 8 kWh/day in winter.

    We also have a 1.5kW PV system. This produces about 2/3 of our power, but as we got in when there was a generous FiT, we don't pay power bills, they pay us.

    CAUTION: PV does not like shade! If there is ANY shade on the panels your output will be substantially reduced. The cells turn into resistors when shaded, so well designed panels have by-pass diodes that, as you may have guessed from the name, bypass that section of the panel. All it needs is a small part of a panel to be shaded to bypass a much larger area of panel: there is a limit to the number of bypass diodes. Upshot of this is you can have a quarter of your panels shaded, but get a 75% reduction in output. It depends very strongly on the geometry of the panels and how the shade interacts with that geometry.

    If you have significant shading from 10am-3pm I think PV would be a mistake.

    I understand thin-film PV suffers less from shading (and possible also better in overcast conditions), but I haven't done any significant research into that.

    Canberra, Australia • Since Feb 2007 • 154 posts Report Reply

  • Lucy Telfar Barnard,

    So, I had a reply from the local distributor I was hoping might pick up importing Dovre. They said "The testing process for the last fire we tested cost closer to $50,000 and the manufacturer will not test any more unless we order a minimum of100 fires . The NZ standards are much more stringent than the European and US testing.
    Sorry but it is not worth it." I don't blame them in the slightest. The retail price overseas for the Dovre Vintage 30 seems to be about NZ$3,000 at discount, but I don't know what the markup would be. Still, 100 fires would be $300K worth of stock to shift.

    So looks like I might be in the market for a locally produced funky model too. In some places, where open fires are still allowed, you could avoid the whole testing regime by doing open fires (like some of those uber-cool focus ones).

    Otherwise, yeah, it'd be the testing that would be a cow.

    Incidentally, some years back, I asked Pyroclassic if they had any plans to make woodburners that were a bit more ... aesthetically pleasing. At the time they responded saying no, and that they thought it was a "classic design" or something equally blind ( :-P ), though I see that since then they have introduced colour options for the surround.

    Wellington • Since Nov 2006 • 585 posts Report Reply

  • James Green,

    So I've come up with my design for a one household experiment on whether a drain water heat recovery system is worth it. Will update once I have some results
    http://distractedscientist.wordpress.com/2014/07/25/drain-water-heat-recovery-weve-ordered-one/

    Dunedin • Since Nov 2006 • 703 posts Report Reply

  • steven crawford, in reply to Lucy Telfar Barnard,

    So looks like I might be in the market for a locally produced funky model too. In some places, where open fires are still allowed, you could avoid the whole testing regime by doing open fires (like some of those uber-cool focus ones).

    Another thing I have been thinking about, is dressing existing burners in new cloths. When I brought the Wagner wood stove, I didn’t buy the accessory parts because they where overpriced and under funky. It’s just a matter of doing the checks and calculations make sure any additions are safe and compliant. That Dovre style, could be replicated to some extent by cladding the outside of a New Zealand made firebox, maybe.

    I am also working in partnership with Andrew, to build top of the line funky coffee machines for home use. Andrew is a precision engineer who went and did a design course at Massy, and like I said before, I am a fabricator. Between us we could build espresso machines from the ground up, between getting wives/ kids off to school/work, vacuuming, hanging out the washing and collecting wives/kids from work/school and the dinner sorted. And we both chivalrous;/)

    Right, so, It’s not difficult to weld pressure boiler and test it, but like getting making wood burners compliant, it’s difficult. There are espresso machine parts that are cheaper to buy of the shelf than to fabricate, so what we are discussing, when we are at the barbers shop, is to concentrate on the exterior design, and shopping for all of the essential parts that require certification. The same concept could be applied to the wood burner. I could make enamel glassed panels to retro clip onto a permitted basic fire box such as this.

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • steven crawford,

    After rereading what I wrote, I see it's badly written:(

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • steven crawford, in reply to James Green,

    And, the system looks elegant enough. It's going to take sting out of the cold, that's for real.

    Atlantis • Since Nov 2006 • 4442 posts Report Reply

  • Aidan,

    Another thing to carefully consider is the size of the water tank you attach to your panels. Often people are advised to get a larger tank as it can store hot water for longer, potentially covering for a cloudy day or two. The danger of too large a tank is twofold: not being able to heat the large mass to a high enough temperature, and having to boost a large volume of water on cold winter days.

    A properly designed tank can have the booster heating element placed higher up, so when it does boost it is only heating a smaller volume of water. Again, it relies on stratification.

    I believe that newly installed electric boost systems here in Canberra are no longer allowed to turn off their booster, as they are paranoid about legionella. This is unfortunate, as it will be a great deal less efficient, harvesting much less solar energy if the tank is always maintained at 60 degC. Not sure what the regs are in NZ.

    It might also be worth it to lag all your hot water piping while you’re redoing things. Especially if the new system is located further away with longer runs of piping. Make sure they use the plastic coated pipe lagging for exterior work exposed to UV. The other stuff breaks down very quickly in sunlight.

    We also had to have a tempering valve in our setup, which we had never had before. Again, new regulations. This drops the outlet temperature to 50 degC to prevent burns, but it also meant we had lukewarm water in the kitchen in winter, until we lagged the pipes.

    Canberra, Australia • Since Feb 2007 • 154 posts Report Reply

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