Using permaculture ethics & design principles to transform an old energy guzzling bungalow into a showcase of sustainable design. It's about energy cycling, building community, self-reliance,creatively using & reusing materials... all without spending heaps of money.

Monday, August 15, 2011

Energy audit and reducing consumption

Principle 4: Apply self regulation and accept feedback
Principle 6: Produce no waste

Small energy meter used to measure the watts used for our 23 year old washing machine
Energy audit
During the last 12 months we used about 2.9kWh of electricity per day, this has not varied much over seasons, which surprised me somewhat. The Jan - Mar quarter is the hottest time of year when we were running the ceiling fans frequently, electric bread maker and also an electric fruit drier which helps explain the higher usage.
July - Sep 2010 (87 days) 238 kWh = 2.74 kWh per day
Oct - Dec 2010 (91 days) 250 kWh = 2.75 kWh per day
Jan - Mar 2011 (98 days) 315 kWh = 3.21 kWh per day
May - June 2011 (89 days) 245 kWh = 2.75 kWh per day
Total power usage for the year 1048 kWh = 2.87 kWh per day
I purchased a small energy meter that allows me to see how much power an appliance draws and uses over time. I have been monitoring some of our major appliances so that I can see where our energy is being used.
Electric fruit drier - 4180W for one batch (plus time in the sun)
Electric bread maker - 330W for one loaf
Fridge (150lt) - 690W per day (before being moved)
Washing Machine - 100W for a load and approx 40W / 70W for water pump (small / extra large load), probably do about five loads per week as we wash nappies.
Water Pump (water pressure for household rainwater supply) - 610W per day average
Computer and peripherals - 1435W (with nine hours 'on-time' during the day)
Entertainment system (TV, DVD and amplifier) - 510W (3 hrs use 4.5hrs on - heavy use for us)
Standby power consumption
While I have been aware of stand by power consumption I didn't realise how much power it actually consumed. I discovered the following:
Water Pump - 19W per hour
Computer and peripherals - 41W per hour
Entertainment system - 14W per hour
Reducing energy use further
We have been considering and applying the following:
Electric fruit dryer - We have decided to limit our use of this appliance and use a solar dryer as much as possible.
Bread maker - We use this during the summer months when the wood oven is not running. 1-2 loaves per week. I'm investigating whether we can use it to make sour dough bread by just using the bake setting as we are not impressed with the quality of the standard loaf that this makes with home ground flour. This will reduce our use slightly, as we wont be using the mix cycle - also we wont need any ingredients other than home ground flour, water and salt.
Fridge - This 150lt bar fridge was given to me when my grandfather died. It was made in the USSR in May 1988. It was positioned in a enclosed space and allowed to frost up considerably. I have since moved it to a more open location that receives little winter sun and have got into the habit of defrosting it every couple of weeks (or when needed). It works much better than it did before and I'm sure uses less power than indicated about (but I haven't measured it yet).
Washing machine - I was surprised at how little power our Maytag washing machine actually used, especially considering that it was made in June 1988, some 23 years ago. It's water use is considerable though, 75lt for a small load, and 150 for a large one. Since we use water collected on site and have had plenty of rain, this has not yet been an issue. I imagine that we will reduce usage later next year as Sen gets out of nappies.
Water Pump
- I've been thinking of using a timer to switch off the pump from 11pm - 7am, saving about 152W per day / 55.5kWh per year (A$12.76 saving per year at 23.5c per kWh).
Computer and peripherals
- We have been changing our usage pattern, turning the computer off during the day when not using it, rather leaving it on all day and relying on sleep mode. Another issue has been the three external drives that are connected, each with it's own power supply, I will only leave the one that I use for back up connected when the computer is on from now on. We also now switch the computer and all peripherals off at the power board, so that there is no standby consumption. This will save us 615W per day / 224.5 kWh per year (A$52.76 saving per year at 23.5c per kWh).
Entertainment system
- My electrician suggested that I add an extra switch on my light switch that controls a power point, which I did. We were using this for controlling a lamp. I have since changed this so that it can control the entertainment system. We now turn off the system when it is not being used, which will save us 273W per day / 99.6 kWh per year (A$22.90 saving per year at 23.5c per kWh).
With these simple measures I estimate that we will save about 1kWh per day / 380kWh per year, over a third of last years energy use. A saving of A$89.30 per year with our new higher electricity rate (assuming all power charged at 23.5c per kWh which it probably wont be).

I feel that using old appliances, the 23 year old fridge and washing machine, is better that throwing them out and buying new 'low energy' ones. The embodied energy in these needs to be valued, and their actual use of power is not huge compared to other areas.
I'm actually surprised at how valuable an exercise this has been, and has made me much more aware of how and where we use electricity. Installing the solar PV system has been a real motivator in exploring and reducing energy use further.
While numbers vary a lot, the typical Australian household uses around 20kWh per day, with the changes mentioned above we are looking at using about 10% of that without compromising our lifestyle, more like 7% (1.4kWh per day) if we were using mains water and not pumping it ourselves. Anda that's with a family of four, which not typical of Australian households.

Thursday, August 11, 2011

Solar PV: Connection

Principle 1: Observe and interact

It took about seven weeks before the system was actually turned on, fortunately this has been during mid-winter, the time of year that generates the least amount of electricity. The hold up was the time it took for the electrical inspection and meter change over. I have not yet received a bill for the meter change over, the total cost so far for the 1.5kW system is A$3390.
I have taken a lot more interest in seeing how our power is being used since we have had the system turned on, while observing our system generate power and feed into the grid. We have generated 54kWhs, exporting 41.8kWhs and importing 18.1 kWhs over the past two weeks, using (54 - 41.8 + 18.1 =) 30.3 kWhs. This is an average of 2.16 kWh per day, which is significantly less than our average over the past year of 2.9 kWh per day.

Grid interactive inverter showing watts generated over a day during mid winter
The newly installed import / export meter showing power exported to the grid over the first day and a half

I received an email from the Alternative Technology Association a couple of days ago with a pre-emtive warning that the Victorian Governments intends to change the premium feed-in tariff. I predict that the generous rate of 60c / kWh will be reduced considerably. The ATA told its members who have recently installed PV systems to contact "your preferred retailer to discuss establishing a premium feed-in tariff contract for when the smart meter has been installed." I had no idea that this needed to be done.Damien from the ATA told me
You have to have a signed ‘premium feed-in tariff contract’ with an electricity retailer in order to obtain the feed-in credit. It is a specific market contract, between yourself and the retailer.
The silly thing is that they don’t just send you this contract, once your system and meter is installed and signed off, as you indicated in earlier forms that you wanted to take part in the feed-in tariff. That’s large, unweildly organisations for you!
I hope that the form you have just filled in is a specific ‘premium feed-in tariff contract’. Only once one of these is signed and dated can you begin to receive feed-in tariff credits.
I contacted Origin, my retailer, and established that I had not yet entered a contract for the premium feed-in tariff. I told them that I was not happy about this situation, as I may have missed out on the reason why I got the system when I did. I filled out the forms and emailed them to Origin today, asking them if I have done it all correctly and when I might find out when this is all sorted out. I got back this response:
Yes this is fine, thanks. As discussed the rate you were on previous to returning this agreement was the standard rate on 23.5c. The 66c will be applied to the account and effective today.
I'm glad I checked this all out, I certainly got a good return on my ATA membership, I think that the email that they sent me will make me thousands of $ over the next 15 years.

Monday, August 8, 2011

Making the most of firewood

Principle 3: Obtain a yield
Principle 4: Apply self regulation and accept feedback
Gourmet combustion stove in full swing, cooking on stove top, drying clothes, boosting hot water, heating oven and warming our house
We obtain multiple benefits from using our combustion stove, because it is designed as a stove / oven / heater and hot water booster, which helps to maximise our yields. We also get the added benefit of a glass door, which creates a fantastic ambiance and allows us to more easily monitor the fire to ensure that it burns hot, key to a longevity and low emissions. One of the inefficiencies with this style of cooker is that we use more fuel than we would for a specific task focused model, because we are performing many functions from the one task. In our case, the advantages multiple functions outweigh the disadvantages.
Some of the other functions that we use our stove for is to dry clothes, dry citrus peel (in oven overnight) for use as firelighters, warm our sourdough bread before baking, keep a large pot of water on the boil for cooking or topping up the bath.
Firewood: sustainable and appropriate energy source
This is an extract from the article of the same name from the eBook David Holmgren: Collected Writings & Presentations 1978 to 2006 available as a free download (article 41 written in 2005).
 ...wood heating has lower greenhouse gas emissions than any other fuel heating. Even poorly managed woodlands supplying wood heaters (60% efficient) up to 400 kms distant, have a net greenhouse gas production of one third that of natural gas and one tenth that of electricity. The figures for sustainably managed regrowth native forest are one third that of woodland systems while new plantations managed for timber and firewood have no net carbon dioxide emissions and actually take 0.17kg of CO2 out of the atmosphere for every kWhr of heat produced.
Heating only requires low quality energies such as passive solar gain or firewood. If we use high quality energies such as electricity for space or water heating then this is wasteful (and therefore environmentally damaging in some way) whether that electricity is from coal or renewable sources. We should reserve electricity for lighting, communications and electric motors.
In a more enlightened sustainable and low energy future, the very real problems of localised air pollution from wood burning in cities needs to be addressed by better training of firewood users, better designed wood burning stoves and most importantly, use of cleaner burning charcoal produced in sustainably managed forests using modern wood gasifer technology which recovers the waste heat.
Our fuel supply
Most of our wood was sourced from the large red gum that was on site, but we have also been using off-cuts from the building of the new house, scrap timber from the deconstruction of the old bungalow and prunings from other trees on site. We also use scrap paper / card and oven dried citrus peel (high oil content) to start the fire. The wood stove provides us with the service of being able to use this renewable natural resource that would otherwise need to be disposed of (or composted).
I expect that this intial supply will keep us going for a number of years, but in the longer term we need access to a good wood source, this means either buying it in (very expensive) or cutting it up ourselves from appropriate locations. If my only option was to buy firewood from a expensive or unsustainable source I would think twice about using a wood stove as my primary heating and hot water back-up system.
Living in the country and having established good contacts throughout the local community makes cutting wood ourselves a good option. We'll source it either from friends or with permission from the appropriate authority from public land. I've learnt how to use and maintaining a chainsaw by working with friends who know what they are doing, gaining enough confidence to operate the machine on my own. Since moving here I've acquired a 30 year old chainsaw and purchased the accessories and safety gear to be able to use it as safely as it can be used.

Storage location
Originally I stacked our firewood in the backyard, against a south facing wall, thinking that this would be the best spot. This was based on the belief that the space wouldn't receive any sun, so it wasn't good for growing, was fairly close to the house and would have good access to the fireplace.
After our first year I realised that this was not a good spot at all. In order to collect wood in winter I needed to get out into the elements, putting on boots and sometimes braving the rain. The other issue with this location was that I would need to transport any new wood that I collected all the way around to the backyard to stack it.
I have since begun stacking wood at the front of the property, where there is better access and it's close to the covered entryway where a smaller stack of wood is stored on a stand near the front door. Using the stand I can measure how much wood we use over the cold season, so I can estimate how much wood I need for the future. I measured the stand space in cubic metres and mark how many times I fill it over the season. By locating our wood stack in a good spot we've saved ourselves a lot of time and effort, a good example of design principle 4.

Chopping, stacking and seasoning
Wood needs to be cut into pieces that can easily fit into our stove. Big rounds may need to dry for quite a while before you can chop them up. I like to leave pieces as big as possible as they will take longer to burn as they have less surface area, but you need smaller sizes too to get the fire up to temperature. I like to use smaller diameter branches for this purpose. I've found that its easy to cut branches to size using loppers while wood is green or with a drop saw when its dry, or if it's too thick for loppers.
It's important to stack the wood so that air can circulate and carry away moisture as it evaporates through both ends of the piece. I make sure that wood stacks lean slightly back to the wall and that the pieces fit tightly with each other. By stacking the wood well I can be sure that it wont easily fall over and can be covered to help keep it dry.
Freshly cut wood has up to 80% moisture content, it must be seasoned (dried) to 20-25% before it should be used. Leaving wood in the rain will cause the wood to reabsorb moisture, reversing the drying process, so it need to be covered for at least 6-9 months to dry sufficiently. Leaving big chunks will take much longer to dry, 2-3 years is not a bad guide, if wood sizzles when it burns then it's not dry enough.
Red Gum and building offcuts stacked and later covered with a tarpaulin to dry
Cutting up and stacking dried red gum branches for firewood using a drop saw
Small branches are cut to length when pruned and stacked for use as kindling. Smaller pieces are chopped up finely and left on site for mulch.
Oven dried citrus skins makes great fire starters because of the high oil content

Efficient burning
Most of the remaining moisture in wood is the resins. When the wood heats up in the firebox the resins emit combustible gases, when these ignite they can account for as much as half the heated output of the fire. If the wood is not properly seasoned then steam is emitted when the wood heats up, preventing the gases from igniting. These unignited gases build up on the glass door, if you have one, and inside the chimney as creosote.
Creosote is highly combustible and condenses in liquid form as the wood exhaust cools up the chimney, solidifying as it dries. As it builds up it increases the risk of a chimney fire, which can burn for an extended period and reach temperatures that can destroy your chimney. Creosote is also caustic and will reduce the life of your chimney.
By seasoning firewood and giving it enough oxygen to properly combust you will reduce creosote formation by burning the gases and sending more heat up the chimney, thereby reducing flue gas cooling.

Learning how to use a wood stove takes time, and each stove has its own intricacies. Practice makes perfect, but these tips that I've picked up may help.
  •  If the firebox is filled with ash it may be a good idea to remove some. With our stove we leave a 25mm bed of ash to prevent the oven below getting too hot, but too much ash prevents the oven getting hot enough. With kitchen stoves it may be best to remove all ash, but the wood heaters it's sometime best to leave a nice bed. I like to leave any coals in the firebox to give them a second chance to burn.
  • Start with well dried citrus peel or eucalyptus leaves as a fire starter, lightly scrunched paper with small dried twigs and sticks stacked around the paper like a tepee. Open up the flue damper and air controls before lighting the paper, and leave the door open until the fire takes. Then close the door, leaving all vents fully open.
  • The fire should get roaring pretty quickly. Once it begins dying down a bit you can flatten out the remaining material and add some larger sticks on the small bed of coals, criss-crossing them to ensure that there is plenty of air around them. Leave all the vents fully open still.
  • Let the fire roar some more. Once it begins to die down again, after 5-10 minutes, add some small logs onto the bed of red hot coals. You can then close the flue damper, but leave the air vents fully open until the logs are well alight.
  • Once there are plenty of hot coals you can add big logs and control the heat of the fire using the air vent. With our combustion stove it's important to open the flue damper before opening the door to add more wood, otherwise smoke will flood into the house setting off the smoke alarm.
  • Burning the fire hot initially helps clean the chimney and glass door and gives you a good coal bed that allows large pieces of wood to burn. Once the wood box is hot it's much easier to burn the combustible gases and make the most of burning wood. You can see this happen with a glass fronted firebox, as flame dances all around the space - which is beautiful to watch. There should be little to no smoke.
  • If the fire dies down and smokes a lot then you will need to stoke it up and add some smaller branches to get it fired up again. Smoldering wood creates pollution and doesn't have the heat to fully combust resins, reducing efficiency. 
  • I tend not to completely close the air vents (we have two) overnight unless there are just hot coals left in the firebox. The thermal mass of the stove keeps the chill off the air overnight after the fire has gone out.
Some other information in this post was sourced from the fantastic article: Wood Burning Basics by Tom Oyen

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