Alternative Technology Assn Forums

1. 

   dymonite69
   Member

   It is estimated that the average Victorian household uses about 11000 kWh each year purely for home heating.*

   Cheap non-electrical options are combustion stove or natural gas heating. The former cannot be regenerated rapidly enough for general use and the latter is a non-replaceable fossil fuel.

   Alternatively a 3 kW solar PV system in combination with a highly efficient reverse cycled air conditioner could provide a similar amount of self-sufficient heating output (excluding all other energy requirements within the household)

   Will this be the future of heating in urban areas?

   * http://www.environment.gov.au/settlements/energyefficiency/buildings/publications/pubs/energyuse-part1.pdf

   Posted Thursday 28 Jan 2010 @ 1:34:40 pm from IP #
2. 

   Buzzman
   Member

   dymonite

   Fortunately, the times when you will most need the air-con unit, the solar panels will be producing at max. In the middle of the daytime, in summer.

   Alas, when you need the reverse-cycle heater element most, it will be when the PV panels are working least efficently. At night, in the middle of winter.

   So I'd go with renewable woodlot fuelled wood stove for winter, preferably with a wet-back to supplement the solar HWS, and use the solar PV for the Air-con in summer.

   Tongue firmly in cheek.

   Cheers
   Buzzman

   Posted Thursday 11 Feb 2010 @ 1:01:37 pm from IP #
3. 

   dymonite69
   Member

   The reason I raise this is that most PV installations are rarely large enough to support this amount of heating and yet it comprises the largest % of household energy consumption.

   Posted Thursday 11 Feb 2010 @ 1:50:49 pm from IP #
4. 

   Eskimoau
   Member

   It would be more efficient coupled to a geothermal heat pump. An added benefit would be that the system wold also provide hot water.

   Posted Thursday 11 Feb 2010 @ 11:32:07 pm from IP #
5. 

   dymonite69
   Member

   So no affordable and sustainable methods of artificially heating a house?

   Here is a bespoke idea I have seen. I wonder how many people could do this?

   http://mtbest.net/heat_pump.html

   Posted Friday 12 Feb 2010 @ 12:32:41 am from IP #
6. 

   mizun
   Member

   You have wood/wood chips!!! Well I have the boiler + Steam Generator.

   Use wood chips to produce steam
   Use steam to generate power(1KW to 100KW)in a steam generator.
   The steam loses potency and comes out as hot water.
   Use hot water to heat up the house/barn/??.
   The water becomes cool and is sent back to boiler.
   Vicious cycle?? NO sir, energy cycle.
   Contact mizuncogen@ymail.com for any clarification.
   Mo

   Posted Tuesday 2 Mar 2010 @ 5:54:24 pm from IP #
7. 

   dymonite69
   Member

   Mizun postulates:

   "Use wood chips to produce steam
   Use steam to generate power"

   Average Oz home uses 33 kWh/day.

   Energy content of wood 4.5 kWh/kg

   Turbine efficiency (max 50%)

   Therefore each house need to burn at least 5.35 tonnes per year to supply their energy needs.

   Questions:

   1) Is there enough wood to go around
   2) Local pollution issues
   3) Cost, size, maintenance, safety issues of home turbine
   4) Efficiency of co-generation, tri-generation process of turning waste heat into heating/cooling.
   5) What happens in peak consumption periods e.g. winter
   6) What do we do with excess heat in summer.
   7) Are we also using heat to drive heat engines or chillers?

   Posted Wednesday 3 Mar 2010 @ 11:53:56 am from IP #
8. 

   PeterReefman
   Member

   Hi Dymonite60

   That's exactly the system I have (although with a 1.5kw PV system...). The house is 8.1 Stars and we need the heating system on about 40 nights per year (cold totally blanket overcast winter days). The 8 Star 2.5kw reverse cycle system uses about 2 kWh on those nights, which mean we have an annual heating bill of about $20, and that energy is made up by surpluses in summer when everyone else has their air-con chugging while we don't need any artificial cooling.

   Where is the figure of 33kWh/d from? I was under the understanding it's 16kWh/d. I'm not saying you're wrong - I want to check if I'M wrong! Does it perhaps include a gas equivalent?

   By the way that Mt Best heat pump looks excellent.

   Posted Wednesday 3 Mar 2010 @ 1:58:56 pm from IP #
9. 

   dymonite69
   Member

   The 33kWhr is based on all energy sources.

   Posted Thursday 4 Mar 2010 @ 12:17:09 am from IP #
10. 

    SANTHOSHKS
    Member

    hi,
    i got a farm where i want generate power of my own by using scrap wood and full fill my power requirement. my power requirement is max 10KW.

    please advise me on avialiblity of full system + cost of it.

    with regards

    Posted Saturday 5 Mar 2011 @ 7:59:57 am from IP #
11. 

    TonyT
    Member

    Solar energy is most economically captured and stored by using a grid-connected photo voltaic (PV) system if the 60cent/kWhr Feed in Tarrif (FIT) can be used to maximise the return for the generated electricity which is fed into the grid and "stored" as cash $.

    When heat is needed, a heat pump uses one kWhr of electricity to deliver 3kWhr of heat.

    A wood fire is best used mainly for its ambience and for the pleasure of watching the flames. Wood will become increasingly expensive and I am doubtful about the environmental friendliness of what comes out of chimneys.

    The highest quality slow combustion heater burns at ? 75% efficiency.
    Growing wood contains 80% water.
    Wood is "dry" when its water content has reduced to 10%.
    Dry firewood typically contains 17MegaJoules of heat energy per kilogram of firewood.
    Burned at 75% efficiency, this dry firewood delivers 13MegaJoules of heat per kilogram of firewood.
    Because one kiloWatthour = 3.6 MJ, 13MJ of heat = 3.6kWhrs of heat.
    Wet firewood delivers much less heat because much heat is wasted to evaporate the water.

    In Adelaide the cost of firewood is increasing every year.
    In 2011 firewood is costing ? $240/tonne = 24cent/kg.

    At this price firewood provides heat at 24/3.6 = 6.7cent/kWhr.

    An additional cost of firewood is the labour to stack the purchased wood in the woodshed, to carry the wood into the house, to feed the fire and to remove the ashes. My estimate for the labour I use to harvest our home-grown firewood totals 16 hours per dry-tonne to cut, collect, cart and stack the fire-wood. Additional daily labour is needed to cart (wheelbarrow) and feed the wood into the fire 5 times per 24 hours.

    A reverse cycle air conditioner delivers about 3kWhr of heat from one kWhr of electricity.
    If electricity costs 21cent/kWhr, the heat from a reverse cycle air conditioner costs 21/3 = 7cent/kWhr and the labour is reduced to ZERO.
    After 20 years of chopping and handling firewood, flicking the switch of our new air conditioner is making me a very happy chappie.

    Posted Monday 18 Jul 2011 @ 2:07:25 pm from IP #
12. 

    dymonite69
    Member

    There is no doubt that heat pumps are the most efficient method of heating. Wood will be the preferred choice for those in remote locations who have a ready supply of it.

    Posted Monday 18 Jul 2011 @ 2:21:12 pm from IP #
13. 

    TonyT
    Member

    The solar PV plus reverse cycle air conditioner heating system that is described by dymonite69 in the first post of this thread can deliver space heating at least cost.

    However we find that comfort is less than ideal due to:
    (1) the noise from the fan, (2) the air movement and especially (3) cold feet caused by the cold air moving at floor level back to the heater.

    Increased comfort can be bought for a higher capital cost but with the same low running costs if the heat pump heats water and that hot water is used for hydronic heating using radiators or, even for even more comfort, in-floor pipes.

    Space heating using a heat pump that extracts heat from tank-water with a temperature of 5 to 10 degrees C is described at
    http://mtbest.net/heat_pump.html

    From a heat source at 5 to 10degC will any heat pump deliver a Coefficient of performance that is between 3 and 5 ?

    Posted Tuesday 19 Jul 2011 @ 7:42:02 am from IP #
14. 

    Jeffbloggs
    Member

    dymonite69 said:
    There is no doubt that heat pumps are the most efficient method of heating. Wood will be the preferred choice for those in remote locations who have a ready supply of it.

    Do you mean efficient as in money wise? There are still losses from electricity production to include as well. Typically you only get 35% of the energy as electricity that was consumed for generation. A HP (Heat Pump) with a COP of 3 (the COP falls with cooler heat source in the winter) effectively becomes neutral if compared with a 90% efficient timber gasification heater. But compared to coal, timber produces only half the emissions for each unit of heat produced. Plus timber is RE (Renewable Energy), coal isn't.

    With a in house NG (Natural Gas), Biogas (aka RNG) or gasification CHP unit, heat can be directly collected from the "cooling" of the CHP and the electricity can still run the HP on top of that, when electricity is not needed for anything else.

    One other point with heat pumps is that they only produce a relatively low temperature heat ie ~50c' from ambient. Timber, Biogas and gasification can be much hotter.

    Posted Tuesday 19 Jul 2011 @ 3:37:14 pm from IP #
15. 

    TonyT
    Member

    JB
    For an un-initiated beginner, what are "NG and gasification CHP units" ?
    Thanks.

    Posted Tuesday 19 Jul 2011 @ 11:09:46 pm from IP #
16. 

    Lance
    Key Master

    NG is natural gas, CHP is combined heat and power...

    Posted Tuesday 19 Jul 2011 @ 11:40:07 pm from IP #
17. 

    Russell Moore
    Member

    NG, Natural Gas, Next Generation? CHP, Combined Heat and Power? It's usual to quote the full name, then later on you can go with the acronyms. I must admit that I had to look them up, and even then I'm not sure what they mean.

    Posted Tuesday 19 Jul 2011 @ 11:44:19 pm from IP #
18. 

    Jeffbloggs
    Member

    Sorry guys for using technobable...but I know that D69 knows what they mean.

    As Lance rightfully pointed out NG is for Natural Gas and CHP for Combined Heat and Power, as in a electrical generator driven by a combustion engine, were the heat is harvested from the engine cooling, and sometimes from the exhaust heat as well.

    Here a 4 piston stirling engine powered CHP: (Price about $8k)

    
    

    Or here a free-piston stirling (aka Sunpower): (price about $5k)

    Here a conventional reciprocating engine CHP:
    

    And here a gasification unit to run your CHP:

    In general any liquid cooled prime mover (combustion engine) can be adapted to reclaim the "waste" heat produced by the cooling circuit, by simply attaching a liquid to liquid heat exchanger (HE). Air cooled engines are more difficult as the airflow is harder to collect and harness for a hydronic system.

    However both allow heat collection from a gas to liquid heat exchanger connected to the exhaust system. It is a simple modification even on small engines. Silicone hoses with hose clamps can be used to re-direct the hot exhaust gases through the HE, which then warms the water in the secondary HE circuit. The heat can then be utilized in a hydronic/radiator/boiler system. Note that the exhaust HE mod needs to to always be full of cooling water, an air pocket can otherwise allow the high temperature exhaust gases to generate supercritical steam in the HE, which can result in spectacular (and dangerous!) failure of the HE or attached devices.

    Like this one by Jamie and Adam:

    Overall there is more than one way to make heat...
    Enjoy.

    Posted Wednesday 20 Jul 2011 @ 5:29:38 am from IP #
19. 

    dymonite69
    Member

    The cost to CHP is only economically feasible where a lot of waste heat is being generated. It is more suited to commercial/industrial processes.

    Posted Wednesday 20 Jul 2011 @ 7:30:17 am from IP #
20. 

    Jeffbloggs
    Member

    D69
    I disagree.
    Ongoing fuel savings alone make them economically feasible in the home if room heating is required.

    Capital costs are similar to installing a wood fired stove, a HWS and a small PV system and it replaces all of these in functionality and convenience. In Europe small CHP units in households are very common. Any CHP will produce 2-3 times as much heat than it's rating in electricity.

    The small 1kW electrical unit (eg Whispergen) will produce most of your electricity consumption, (winter it can run 24/7, unlike PV) and produce enough for all HWS and room heating (3kW from waste heat from stirling alone, 14.5kW from afterburner on same HE in the device) and with a HP/Air-con even do cooling in the summer as well.

    They are already feasible from 1kW in size, which is even good for apartment sized dwellings, hence the range of CHP units already available at that size. In Australia they are yet to be brought to market. (Even though the Whispergen unit is originally from NZ)

    Do you care to run some comparisons with me?
    Say between solar ET&PV, HP HWS, wood, gasification and biogas for RE sources and NG, coal and diesel for fossil fuel sources?

    I think it would be interesting to see. Maybe we can share a spreadsheet via google docs. Do you want me to start one and post a link/screenshot?

    (P.S. No comment on my post to you above regarding your comment that HP are the most efficient for heat?)

    Posted Wednesday 20 Jul 2011 @ 9:47:20 am from IP #
21. 

    dymonite69
    Member

    How much is a 1KW unit?

    Posted Wednesday 20 Jul 2011 @ 11:47:32 am from IP #
22. 

    gazmo88
    Member

    D69 asked:
    How much is a 1KW unit?

    GBP 3000 :
    http://www.greenconsumerguide.com/powergenminisite/whispergenunit.htm

    Posted Wednesday 20 Jul 2011 @ 12:15:20 pm from IP #
23. 

    dymonite69
    Member

    $9000 AUD. And what source of heat are you using to power it?

    Posted Wednesday 20 Jul 2011 @ 12:22:04 pm from IP #
24. 

    gazmo88
    Member

    D69 said:
    $9000 AUD. And what source of heat are you using to power it?

    actually thats 4,502.10 at the current exchange rate.

    The marine units I have seen run on diesel, but I believe the domestic units deployed in Holland run on town gas. Of course, being a stirling engine it could run on anything that produces heat.

    Posted Wednesday 20 Jul 2011 @ 12:37:50 pm from IP #
25. 

    Jeffbloggs
    Member

    D69
    I wrote the prices on the relevant videos I posted. The complete Whispertech system with boiler, installation etc is about $8k. The Baxi version is a bit cheaper, but effectively only has 2 moving pieces. Note as "external combustion engines" neither stirling engine combusts fuel inside the pistons and as a result neither requires oil changes etc. They can also handle various liquid and gaseous fuels. Ideal for gasification fuel sources even with unfiltered syngas.

    The ultimate version would be like this solar powered one from Infinia:

    Just add some gasification/biogas for fuel and a few LiFePo4 batteries to power the integrated inverter and allow energy production/consumption decoupling. Bonus: solar thermal for heat and sun tracking included.

    Posted Wednesday 20 Jul 2011 @ 12:44:20 pm from IP #
26. 

    dymonite69
    Member

    What is the efficiency? Diesel $1.33/L providing 10kWhr energy. So 13c/kWhr

    Posted Wednesday 20 Jul 2011 @ 12:47:45 pm from IP #
27. 

    Jeffbloggs
    Member

    dymonite69 said:
    What is the efficiency? Diesel $1.33/L providing 10kWhr energy. So 13c/kWhr

    Smaller units are around 25% fuel to electrical, larger ones have achieved over 45%.

    Your diesel calculation is total fuel energy btw not electrical output in kWh. Multiply by about 20% for conventional diesel 5 kW CHP or 15% for petrol to get eletrical output, but multiply by 1-2 for heat ex tractable from water cooling circuit of CHP and the same again from a exhaust HE. Overall +90% of the fuel energy can be recovered from the CHP. As above apply ca.25% for Stirling.

    Posted Wednesday 20 Jul 2011 @ 12:59:24 pm from IP #
28. 

    dymonite69
    Member

    So 19.5c/kWhr electrical

    13c to heat 18-36L of water?

    Posted Wednesday 20 Jul 2011 @ 1:08:34 pm from IP #
29. 

    sun2steam
    Member

    This unit http://www.bluegen.info/en/bluegen/home/ is made by an Australian company and according to their web page can produce electricity from gas with 60% efficiency using fuel cells. This is impossible with small mechanical engines. The wast heat can be used to heat water bringing overall efficiency to 85%. This might actually be a better mach for the mild Australian climate.

    Unfortunately the product is still in the pilot stage. As far as I can remember Harvey Norman has become the sole Australian distributor. Unfortunately they wanted to sell it only to industrial customers. Maybe this has changed by now. http://www.harveynormansolar.com.au/BlueGEN.html

    Posted Wednesday 20 Jul 2011 @ 1:43:22 pm from IP #
30. 

    Jeffbloggs
    Member

    dymonite69 said:
    So 19.5c/kWhr electrical

    13c to heat 18-36L of water?

    From what fuel source? Natural gas? And what temperature water?

    -

    S2S
    Interesting link thx. Methane fuel cells are much better than hydrogen ones. At least the fuel is storable and one can produce it easily from Biogas! We had a look at 200kW methane fuel cells from Mercedes last time we were in Germany. It was an eye opener even 4 years ago how far they have progressed. Have you seen any 5 to 25kW versions? Would be interested in a few of those.
    Regards
    JB

    Posted Wednesday 20 Jul 2011 @ 2:02:45 pm from IP #

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