tag:blogger.com,1999:blog-7762293635463803805.post5572591207516955070..comments2022-10-19T15:54:10.874-07:00Comments on Guesstimated approximations: Holistic home temperature managementAngus Wallacehttp://www.blogger.com/profile/01518875828382696708noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-7762293635463803805.post-33559992706561562162016-07-20T21:29:36.678-07:002016-07-20T21:29:36.678-07:00Thanks, the excess PV thing shouldn't be an is...Thanks, the excess PV thing shouldn't be an issue long term if the utility/retailers work with their customers and trade electricity, society will find daytime use for it. The resistive water heating saga is created by some short sighted policy (SIGH) I'm hoping it will pass before the utilities get their customers too far offside and destroy their own business.<br /><br />Lloyd makes a good case (treehugger) sash windows are great for cross ventilation but they also leak heat like a sieve. If we dont have the tree for afternoon shade as well, its going to be bleak, its all about combinations that work together. The alternative, insulation, double glazing, a heat exchanger for fresh air and air conditioner will certainly do much better on some sites particularly if there is a chance of mould from condensation.<br /><br />A thermal mass floor that is not insulated underneath is almost impossible to warm with heated room air, the walls change temperature a lot faster than a floor because they leak less heat out to the environment. My observation about floor coverings is the plusher the pile the colder it feels, the captured air layer in the carpet is the same temperature as the mass underneath. I think short tight pile or weave would be better for a rug. The benchmark I go by is standing barefoot on a flattened cardboard box, try it, if a floor surface can match that, its a winner. <br /><br />Given a choice, I would insulate a thermal mass floor out of the living space rather than leaving it in.<br /><br />A pressurised firebox is not something that is is available on wood heaters in Oz.. yet, there are some tech hurdles to clear. I see some merit in choosing a freestanding heater over the inserts, mainly because with an insert the circulation fan has to run to extract heat. Very little radiant or convective heat gets into the room without it running. It's hard to maintain a temperature with an insert heater (particularly a big one) they are a blast furnace when you stoke them and dribble to nothing at an idle.<br /><br />Yes, the heat in the secondary burn area when that extra bit of hot oxygen is introduced is the key to complete combustion, however, if the primary firebox is not hot enough some of the combustible molecules are never formed in the first place. Fires that run hotter need furnace grade firebrick or cheap easily replaceable parts, not popular in a price sensitive industry. It is easier to sell brass trim rather than proper efficiency.<br /><br />I was tossing a few ideas around with somebody last week, we reckon a heat pump with a small inverter driven scroll compressor pushing a hydrocarbon refrigerant through a solar collector could be extremely efficient, we could heat water, thermal mass and interior spaces all from the one unit with no frost risk on the collector side. In theory it could work down to -40C.<br /><br />I guess it is all relative, burning 4 tonne of redgum is worse that 1.5 tonne for the same result, is worse than burning low grade chip off-cuts or plantation trimmings, is not as good as not having to stoke a fire in the first place.<br />cheers<br />PS Just read Chris's post before I hit the publish button he has covered it well. Architects talk about thermal bridging, every time there is a join or fitting that cuts across the thermal envelope of a building heat is lost, window frames and joists are a large part of that.Yahoo2https://www.blogger.com/profile/06808439179020727092noreply@blogger.comtag:blogger.com,1999:blog-7762293635463803805.post-23083604494397103552016-07-20T19:55:18.646-07:002016-07-20T19:55:18.646-07:00Hi Angus,
The term management is spot on. A great...Hi Angus,<br /><br />The term management is spot on. A great idea. Control does lend the wrong mindset to the whole issue.<br /><br />I also have to second Steve's comment about thermal mass under floors. I have thick R3.5 batts under 19mm timber tongue and groove flooring and even on the coldest day I can walk around barefoot if I so chose. Do that on a concrete floor and you immediately know that it takes a huge amount of energy to stop the thermal mass draining the heat out into the soil and no amount of insulation can stop that loss to the soil. And the cold radiates at you if the house has not been mechanically warmed for many long days - even if the air is warm.<br /><br />Why do we make houses on concrete slabs then? Because it is quicker and takes less skill to do than strip footings or stumps. And labour costs a huge amount. Nuff said really. Stumps are not a cheap way to build a house.<br /><br />I agree with your overall strategy. Local has the benefit of being cheaper and easier to manage too as you get immediate feedback.<br /><br />I don't reckon people think much nowadays about actively managing for the inside temperature in a house. They used to do that when I was a kid.<br /><br />I can't really speak for Adelaide, but there is no heat in the winter sun here, so you can have as much sunlight streaming in through windows as you can manage to achieve, but it won't actually heat anything. Otherwise you'd be able to grow tropical plants in a greenhouse all year around down here - but that is not possible this far south. You know, I've often wondered whether this viewpoint favours the societal preference for large windows in houses? Dunno, but if you look at older houses you generally notice that the windows are very small in proportion to the walls. Sure, glass was expensive back then, but it isn't cheap nowadays either.<br /><br />Again, I'm generally suspicious of talk about eaves too instead of a proper full sized verandah shading external walls and windows. We do things in buildings because they are cheap and not because they are good and thus that is what is promoted as being the correct solution. And many of the processes involved in building are skewed towards project builds.<br /><br />Wood heating is great as I can manage that energy resource from start to finish, although it has taken me at least six years to come to such an understanding. It is a complex resource. In a city, to use coal fired electricity means that you are laying waste to somewhere else. You should travel to the Latrobe valley someday and see the smoke stakes from the brown coal power plants. Oh my!<br /><br />Cheers<br /><br />ChrisFernglade Farmhttps://www.blogger.com/profile/06950962122594709186noreply@blogger.comtag:blogger.com,1999:blog-7762293635463803805.post-18412429822183330272016-07-20T17:04:22.158-07:002016-07-20T17:04:22.158-07:00Hi Steve,
Thanks for your great comment and inter...Hi Steve,<br /><br />Thanks for your great comment and interesting links.<br /><br />The TreeHugger article is interesting. I think it's highlighting the tension between new-build and retrofit scenarios, as well as the greater context of urban planning. The comments are interesting too. I think that a lot of consideration needs to be given to the specifics of the site. For example, if shading means that winter sun is affected, then it doesn't make sense to have a lot of Equator-facing glazing since even the best glazing loses a lot more heat than a well. This is precisely the dilemma I face at my house -- a large gum tree means our North-facing wall only gets winter sunshine form about midday onwards. I don't want to put too much glazing there!<br />The One Step Off The Grid article is intersting too. I am planning to buy one of these radiant heaters, and wire it with a movement sensor so that it automatically switches off if no one is there. See how that goes... I don't think I agree about using "excess" solar PV to resistively heat water though -- I still support either solar HWS or heat-pump. This is for the simple reason that solar PV energy that is exported to the grid is not "wasted".<br /><br />Your thoughts about flooring are interesting. I guess historically, floors would be heavy and cold, and in winter they'd be covered with a rug (that was put away in summer). That has the best of both worlds, perhaps?<br /><br />Our current combustion heater is about 60 years old, and exhausts into a chimney. It's very inefficient. Perhaps it would be better to replace it with a fan pumped one so that I can have a cleaner burn and also capture the heat in the house without it going up the chimney. Certainly having an exposed flue like on the 800LE (which looks good, btw) helps a lot.<br />I am presuming that a strong secondary burn will consume most/all of the smoke and soot?<br /><br />I will try to incorporate some of these ideas/links into the article prior to publication. Thanks very much for your suggestions!<br /><br />Cheers, AngusAngus Wallacehttps://www.blogger.com/profile/01518875828382696708noreply@blogger.comtag:blogger.com,1999:blog-7762293635463803805.post-5969025260336416782016-07-20T03:49:31.984-07:002016-07-20T03:49:31.984-07:00Everything I ever knew or said about green sustain...<a href="http://www.treehugger.com/green-architecture/everything-i-ever-knew-or-said-about-green-sustainable-design-was-probably-wrong.html" rel="nofollow">Everything I ever knew or said about green sustainable design was probably wrong</a><br /><br /><a href="http://onestepoffthegrid.com.au/a-journey-to-fossil-fuel-freedom-no-heat-pumps-required/" rel="nofollow">no heat pumps required One Step Off The Grid</a> <br />Hi Angus, some links for your consideration. Im not a fan of thermal mass floors myself, cold feet equals unhappy me! insulation under a thin low conductive surface ie (polyurethane sealed wood) is barefoot anytime of the year. <br />Wood heaters are tricky, they need to reflect enough heat back into the fire and secondary combustion area to keep it above a minimum temperature. Going out on a limb I'm guessing 800-850 C for the primary and at least 500 C for the secondary chamber. Much below that and the high heat generating clean burn collapses and takes the chimney draw with it. Some of the super low emission heaters lose their draw occasionally, so I am thinking of backing off the ragged edge and trialing a local heater next winter <a href="http://blazefireplaces.com.au/freestanding-heaters/" rel="nofollow">*800LE</a>. Perhaps modifying it to run pressurised with a tiny fan for overnight burns and playing around with the insulation to keep the fire internal temp up a little higher. I'm confident it will run well without the mods but Hey! where's the fun in that. I have looked at a lot of wood heaters in the last 5 years and I am not very impressed, I think we are paying for form rather than function.<br />SteveYahoo2https://www.blogger.com/profile/06808439179020727092noreply@blogger.comtag:blogger.com,1999:blog-7762293635463803805.post-74947646233634809052016-07-18T21:26:32.781-07:002016-07-18T21:26:32.781-07:00Chris,
I'm particularly interested to hear yo...Chris,<br /><br />I'm particularly interested to hear your thoughts on my recommendation against using wood fires in (sub)urban areas, given your experience with wood heating in rural areas.<br /><br />Cheers, AngusAngus Wallacehttps://www.blogger.com/profile/01518875828382696708noreply@blogger.com