Alternative Technology Assn Forums

1. 

   cava
   Member

   As some on this site know, we are in the process of building a new house on acreage, on the outskirts of Melbourne. The goal is to try and be as independant as possible from the grid, and we are toying with the idea of a RAPS.

   To that end today I went looking for induction hotplates, to see what was available in the market. It was then that the penny dropped that an induction cooker typically used 7 kW on maximum settings. For the record we will have two (2) kitchens, so I am not sure that a bank of batteries will be able to handle the drain.

   The question I pose is, is induction cooking a feasible option for a RAPS, or should I look at gas cooking? Currently, we have a reticulated NG supply on the block.

   Posted Friday 23 Dec 2011 @ 10:30:55 am from IP #
2. 

   rockabye
   Member

   I'd go gas even if on mains power.

   If the power fails you can still cook as well. And if you must try one a portable induction cooktop is about $150.

   Posted Friday 23 Dec 2011 @ 7:13:45 pm from IP #
3. 

   yabbietol
   Member

   Not sure about induction cooking, but gas from cylinders in remote areas is a problem. If you have access to town gas go for it (make sure all above ground pipes are metal), but if you need to have gas cylinders be careful. The bottled gas is much more expensive than town gas once it is delivered to your house. The cylinders are often positioned next to the house with safety vents pointing towards the structure, which in the case of fire almost certainly will totally destroy the house.

   As a volunteer fireman we dread fires where gas cylinders are on or near the house. Gas cylinders pose a real hazard to all houses with them fitted in bush fire prone areas. Many houses lost in major bush fires are lost because of gas cylinders either venting and acting like a blow torch on the structure or just by the cylinder overheating and exploding. If you must have gas in a remote area place the cylinders away from the house in fire resistant structure or use a bullet cylinder behind a well constructed berm.

   Posted Friday 23 Dec 2011 @ 8:27:33 pm from IP #
4. 

   bundy
   Member

   We have been going through the house extension journey and I looked closely at Gas V's Induction for this very reason as they seem to be very power hungry. However what I found is the running cost differential is minimal compared to Reticulated Gas. (Bottled gas may in fact cost even more to run)a

   One of the reasons is Induction heating is a lot more efficient in getting the heat to where it is meant to be on the food. With induction heat comes from the base of your pan not an element or flame underneath the saucepan. Where as burning gas a lot of heat is actually lost up the sides and around a saucepan. I understand that with gas up to 50% of the energy goes to heating your room not the food, whereas Induction gets the heat right where it is wanted.

   So if it helps in our case we went induction based on
   - Ease of cleaning a flat glass plate V Gas hobs
   - Greater control over temperature settings particularly at low temps
   - Safety (No hot elements and no gas can leak with small Kids that was a big factor)

   At the end of the day Energy use differential really was irrelevant.

   The concept if you lose power its handy to have gas really didn't matter to us either as someone pointed out you can always use the BBQ if you lost power (Presuming you have one)

   How this though relates to RAPS I have no idea as I am not familiar with that term

   Posted Friday 23 Dec 2011 @ 9:41:33 pm from IP #
5. 

   rockabye
   Member

   RAPS is short for Remote Area Power Systems. The fire risks are one disadvantage but then again many fires are started from electrical systems as well. However I agree with the precautions suggested.

   As for costs the monthly service charge for NG is so high it dwarfs our lpg consumption.

   Posted Friday 23 Dec 2011 @ 11:11:29 pm from IP #
6. 

   Russell Moore
   Member

   yabbietol is right about bottled gas, I remember about 10 years ago we had a bushfire come out of Holsworthy army camp, and impact on houses at Wattlegrove. The only house to catch fire was one that had gas bottles on the side of the house facing the bush. The bottles vented, the gas caught fire and shot up the wall of the house and into the eaves and roof.

   That said, we have bottled gas (2x9kg tanks), it costs about $17 to fill one tank, and the two tanks last us over a year. Admittedly we are not big users of the stove.

   Posted Saturday 24 Dec 2011 @ 12:44:53 am from IP #
7. 

   PeterReefman
   Member

   Some other thoughts on Induction Vs Gas hotplates.

   * Induction is 80-90% efficient as the heating mechanism IS the cooking pan/dish. Conversely, Gas cooking is generally only 20-30% efficient, as most of the heat does not absorb into the cooking pan/dish.

   * Gas requires oxygen to operate, while releasing Nitrogen Oxide. So reduces air quality, and because of this requires the kitchen area to have extra ventilation which may have heating/cooling impacts.

   * Gas cooking will also increase the room temperature, which will increase artificial cooling needs during summer (This will be offset by helping out in winter, but air quality/ventilation is impacted as mentioned above)

   * Induction cooktops have the highest levels of both safety and cleaning.

   * Induction is far more suited to a 100% renewable energy economy, as the reliance of natural gas for uses such as cooking means we need this fossil fuel to be extracted, refined, and distributed across Australia.

   These points are taken from the Cape Paterson Ecovillage - Sustainable Housing Guidelines. The CPEV will not have any gas use other than portable barbeques with small bottles (and even then electric BBQs are recommended.

   Hope that helps, and all the best with it

   Posted Saturday 24 Dec 2011 @ 1:41:08 am from IP #
8. 

   cava
   Member

   Thanks for all the responses. However, my original concerns are to do with the fact that if we proceed with a RAPS, will we be able to operate the induction hotplate(s) x 2 satisfactorily? Or is gas the better option?

   It is an option to beef up the number of PV's and storage batteries - but then it starts to become seriously uneconomic.

   Posted Saturday 24 Dec 2011 @ 11:19:37 am from IP #
9. 

   me
   Member

   Hi

   I guess you need to work out how much power that you will actually use if you get two induction hot plates.

   Will they both be used at the same time? How often will they be used for? How many people will be using them (or how many will it be cooking for)? How long/what do you cook? Do you have induction cookware? Do you use lids or well insulated cookware?

   One plate used several times a day will use more power than two used less often. Using lids can make a huge difference. If you do not have any iron or stainless steel cookware that will be an added expense.

   I do not use induction cooking and I understand it is much more efficient than gas but does that matter if it dearer to use?

   If I was going off grid I would use 12 volts for cooking but that is because mostly it would be just for me and I limit what I cook to things like frying and boiling so I only need about 20 to 40 watt hours to cook a meal for one....it may be much more in-efficient but who cares if it actually uses far less power! If you cook a wider range of foods and for a family 12 volt would be much less practical and to me it would then be simply which is cheaper of induction or gas (or what else is available) or if in the same range which is easier to work with.

   Posted Saturday 24 Dec 2011 @ 7:01:10 pm from IP #
10. 

    Bushwalker
    Member

    cava said:
    Thanks for all the responses. However, my original concerns are to do with the fact that if we proceed with a RAPS, will we be able to operate the induction hotplate(s) x 2 satisfactorily? Or is gas the better option?

    It is an option to beef up the number of PV's and storage batteries - but then it starts to become seriously uneconomic.

    Well, what is the specifications for your RAPS? Could it conceivably handle the load from your two induction cooktops as well as the normal load?

    FWIW we have Gas LPG cooking using a pair of LPG cylinders. Not sure of the capacity but the cylinders are about 1.4m high. The cylinder rental costs more than the gas consumed, we typically need to swap a cylinder every year or so.

    The issue regarding room venting and heating effects of gas are correct, but overstated. In reality with an induction cooktop you would run your range hood for reasons other than to remove the products of gas combustion anyway, and any decent rangehood vents outside.

    Posted Saturday 24 Dec 2011 @ 10:07:30 pm from IP #
11. 

    PeterReefman
    Member

    Fair enough - but you say you want to as independant as possible from the grid, but then are okay using the NG grid?

    Sorry I don't know your exact situation, but my own opinion is it doesn't make a lot of sense to spend a LOT more money/resources getting off one grid (batteries, etc to get off the electricity grid) when grid-interactive solar is now an established practice that can contribute to a 100% renewable energy supply which we as a society should be aiming towards; and then hook up to another grid which is and will likely stay solely reliant on fossil fuel.

    I also don't know what your budget/quotes are to go RAPS; but I know good companies that are installing 5kw Grid-connect PV systems for under $13k now, and 30kW systems for around $50k

    Posted Sunday 25 Dec 2011 @ 6:48:33 am from IP #
12. 

    dymonite69
    Member

    We use LPG tanks solely for our stovetop. A 45kg tank lasts 18 months. That is about 3.6 MJ/day or just over 1 kWhr. If we switched to an induction that is twice as efficient we would reduce energy use by 0.5 kWh (or about 10c/day).

    Posted Tuesday 27 Dec 2011 @ 3:49:48 am from IP #
13. 

    Bushwalker
    Member

    dymonite69 said:
    We use LPG tanks solely for our stovetop. A 45kg tank lasts 18 months. That is about 3.6 MJ/day or just over 1 kWhr. If we switched to an induction that is twice as efficient we would reduce energy use by 0.5 kWh (or about 10c/day).

    And save gas bottle rent as well as reduce your fire risk.

    On the other hand, tearing out a working cooktop and buying/installing a new one would cost years of running costs and add to the embedded energy. Could take a long time to break even from both a financial and energy POV.

    Posted Tuesday 27 Dec 2011 @ 7:05:14 am from IP #
14. 

    cava
    Member

    Thanks for the feedback everyone. And apologies for not responding sooner, but we have been having internet access problems.

    One of the concerns that I have is, security of supply. This is primarily because, it is my belief, that we are on an economic precipice that no one has seen since the 1930's. Whilst no one can be insulated from this entirely, some decisions are better than others.

    We currently have both gas and electricity supply to our block, but from a historical perspective the electrical supply can be erratic, and I feel that there will be problems of supply in the future - hence the RAPS. I am not interested in going for a PV system that feeds back into the grid, as I see that there will also be problems with this.

    Reticulated gas supply is more constant, apart from the Longford VIC debacle, there has never been a supply issue with NG in Australia, that I am aware of.

    The house will have two (2) kitchens and will cater for seven (7) adults. Currently, my thoughts are to have one kitchen equipped with an induction hotplate and the other with a gas hotplate. An ancillary wood fired stove is to be installed in the BBQ/entertaining area - just in case. We also have a small woodlot!

    Posted Tuesday 27 Dec 2011 @ 8:53:02 am from IP #
15. 

    bundy
    Member

    cava said:

    One of the concerns that I have is, security of supply. This is primarily because, it is my belief, that we are on an economic precipice that no one has seen since the 1930's. Whilst no one can be insulated from this entirely, some decisions are better than others.

    Then really your decision wont be based on the merits of Induction V's Gas more of your personal belief of what the future holds for energy security.

    If you think Power is going to be "rationed" in some way or become so uneconomical that only a few can afford it (and that argument is for a different forum) however even if that extreme scenario did unfold I can not see how NG prices and supply would not also be affected, both in price and availability no matter what has happened in the past.

    At the end of the day Energy is energy and if we dont have enough of one source to go around consumers and industry will use whatever alternate sources available to substitute. Thus if I am reading you correctly all energy supplies will be stretched not just Eletricity.

    To be honest it seems an extreme scenario you are banking on and it cant see why you wouldn't feed back excess solar PV to the grid based on what is available today. As you are on the grid you may as well benefit from it.

    If you wanted batteries down the track worry about that then (or by a Generator and start storing diesel)

    Posted Tuesday 27 Dec 2011 @ 10:05:47 am from IP #
16. 

    cava
    Member

    Thank you for the response. It almost seems that I am wearing a tin-foil hat at times.

    By the nature of the beast, it is easier to ration electricity than gas. Electricity supply is also more prone to supply interruptions than gas supply, and please correct me if I am wrong. However, if I had a PV system that was grid connected, and it went down for whatever reason, my understanding is that I cannot draw from the system. In effect, I would be like others, ie left with no power when I wanted/needed it! Which really would, in my circumstance, defeat the original intent.

    Posted Tuesday 27 Dec 2011 @ 10:47:17 am from IP #
17. 

    bundy
    Member

    cava said:
    Electricity supply is also more prone to supply interruptions than gas supply, and please correct me if I am wrong. However, if I had a PV system that was grid connected, and it went down for whatever reason, my understanding is that I cannot draw from the system. In effect, I would be like others, ie left with no power when I wanted/needed it! Which really would, in my circumstance, defeat the original intent.

    Yes you are right you would lose local power if you had PV feeding back to the grid and not into batteries, however you lose your ability to generate when the sun sets too so there are trade off's everywhere. However unless you have a huge bank of batteries a week of cloud and rain may see you losing power when all those around you have grid supply so you would need to factor in a Generator as well.

    I certainly don't know your situation nor how unreliable your supply is but unless it was down for hours every day I personally would be staying on grid.

    Have you thought of even having a standby NG Generator that could kick in to provide power should the grid ever fail? Same as they do in most commercial premises (Usually diesel not NG but same concept)

    If you scenario of no Grid power whilst still having NG supply eventuated you would still have your NG supply to generate locally, and there is no need to cut yourself off from a very useful utility such as Grid supplied power. Plus batteries don't last forever and do need to be replaced (currently at considerable expense)

    Posted Tuesday 27 Dec 2011 @ 11:02:57 am from IP #
18. 

    cava
    Member

    bundy said:Have you thought of even having a standby NG Generator that could kick in to provide power should the grid ever fail? Same as they do in most commercial premises (Usually diesel not NG but same concept)

    Thanks for the response.

    Point taken and we have been looking into NG generators. Currently have a diesel generator which gets used intermitently, as recent as this week actually.

    Posted Tuesday 27 Dec 2011 @ 10:10:02 pm from IP #
19. 

    KimW
    Member

    Hi,
    Can I make a comment about the cooking on both induction vs gas. Currently living in a house with induction cooktop and find it is not able to generate enough heat to cook certain things eg wok.
    As a result, for the small amount of energy used coking, will be getting a gas cooktop in my own house.
    Does anybody else have similar experiences in using these appliances?
    cheers Kim

    Posted Friday 30 Dec 2011 @ 1:28:45 pm from IP #
20. 

    bundy
    Member

    KimW said:
    Hi,
    Currently living in a house with induction cooktop and find it is not able to generate enough heat to cook certain things eg wok.

    Does anybody else have similar experiences in using these appliances?

    Kim do you have a flat bottomed or rounded Wok?

    If a traditional round Wok there is probably not enough surface area covering the induction zone. I found induction to be far hotter than Gas as gas is actually limited to the size you can use indoors (15MJ from memory) due to safety reasons, and as mentioned you lose a lot of that energy up the sides of the pan.

    For true WOK cooking you would have a flame two or three times as big - like a restaurant but it's just not allowed as too dangerous in the home.

    Anyway try a Wok built for induction, (Or turn up the heat in a frypan for a test) as you might be pleasantly surprised at how hot it actually gets

    Posted Friday 30 Dec 2011 @ 9:28:27 pm from IP #
21. 

    Bushwalker
    Member

    Agree re the gas burner sizing. You need about 50MJ and up for an effective wok burner. Even the BBQ's like Beefeater with 'Wok Burners' are only 12 or so MJ. You can buy decent burners at camping shops but I'd hesitate to run these inside the home.

    I also agree with Kim regarding Woks and induction cooktops. The whole point of the wok is that it's a large, hot, rounded cooking surface. Yes, the flames run up the side of the wok, heating the sides (it's not a straight sided pot like a saucepan). Used properly, they don't sit still for long. If you put a flat bottom on it and depend on it being level and in contact with the induction cooktop then it will be wok by name but not by nature, you might as well use a frypan.

    Wok cooking by nature is better outdoors anyway, so I think the best outcome might well be an induction cooktop inside and a decent gas wok burner outside with the BBQ. That gives you options in a power failure too.

    Posted Friday 30 Dec 2011 @ 11:28:32 pm from IP #
22. 

    dymonite69
    Member

    Bushwalker said:
    Agree re the gas burner sizing. You need about 50MJ and up for an effective wok burner. Even the BBQ's like Beefeater with 'Wok Burners' are only 12 or so MJ. You can buy decent burners at camping shops but I'd hesitate to run these inside the home.

    You might find a commercial induction wok burner on ebay. There are a few Hong Kong manufacturers that do > 7 kW burners.

    You will need a commercial rangehood to match to suck up the cooking vapours.

    My mum runs a 45 MJ gas burner outside. I once almost singed my eyebrows off with it. My brother in law's mother has a separate area next to the kitchen to do her stir fries so that it doesn't make the whole house smell.

    Posted Saturday 31 Dec 2011 @ 4:47:35 am from IP #
23. 

    macklinvinger
    Member

    hello guys i am mack from torranto.
    nice to meet you.

    Posted Saturday 31 Dec 2011 @ 9:56:41 am from IP #
24. 

    Bushwalker
    Member

    dymonite69 said:

    My mum runs a 45 MJ gas burner outside. I once almost singed my eyebrows off with it. My brother in law's mother has a separate area next to the kitchen to do her stir fries so that it doesn't make the whole house smell.

    Yep, which is why I said I'd hesitate to run one inside the house.

    Reality: If you want to run a proper wok burner in a domestic situation, run it on gas and run it outside. That way it won't cost you much and it will work as expected, whereas an induction burner will not:

    http://en.wikipedia.org/wiki/Wok#Induction

    Induction cookers generate heat in induction-compatible cookware via direct magnetic stimulation of the pan material. While carbon steel and cast iron (the most common wok materials) are induction-compatible metals, induction cooking also requires close contact between the cooking vessel and the induction burner. This presents two problems when using a wok on an induction cooktop: traditionally shaped woks, which are round-bottomed, don't have enough contact with the cooking surface to generate notable heat; and the tossing technique, where the wok is lifted off the burner and agitated, will break contact and turn off the burner.

    Flat-bottomed woks make sufficient contact to generate heat. Some cookware makers are now offering round-bottomed woks with a small flat spot to provide induction contact, with a specially-designed support ring; and some induction cooktops are now also available with a rounded burner that is able to make contact with the rounded bottom of a traditional wok. In both cases, the food will need to be stirred with a cooking utensil, instead of being tossed by lifting the wok itself.

    Really, induction hobs are just not made for wok cooking. If you must use induction, just use a frypan.

    Posted Saturday 31 Dec 2011 @ 10:18:27 am from IP #
25. 

    KimW
    Member

    Hi all,
    thanks for the comments.
    My example of a wok is not the only "issue" that my partner has with induction.
    Cooking anything in a frypan where you are trying to cook quickly on a hot surface, the induction method just does not seem able to generate enough heat to match a gas flame.
    I am using a De Dietrich Model DT1709X, which is rated at 10800 W.
    cheers Kim

    Posted Saturday 31 Dec 2011 @ 10:38:03 am from IP #
26. 

    dymonite69
    Member

    Bushwalker said:
    Really, induction hobs are just not made for wok cooking. If you must use induction, just use a frypan.

    http://www.smeg.com.au/Product-306-78cm_High_Power_with_Wok_Recess_and_Boost_Induction_Cooktop.aspx

    http://www.gourmetandkitchen.com.au/premium-buffetware.html

    http://restaurantsplus.com.au/listings/catering-equipment/cooking-equipment/wok888-dl-5kw-induction-wok

    Or just get one of these for less than $100 - 67 MJ of pure fun:

    http://www.auscrown.com/page/shop/flypage/product_id/169/a/category/e/commercialcastironburners_duckbillburners

    Posted Saturday 31 Dec 2011 @ 1:10:05 pm from IP #
27. 

    Bushwalker
    Member

    dymonite69 said:
    http://www.smeg.com.au/Product-306-78cm_High_Power_with_Wok_Recess_and_Boost_Induction_Cooktop.aspx

    http://www.gourmetandkitchen.com.au/premium-buffetware.html

    http://restaurantsplus.com.au/listings/catering-equipment/cooking-equipment/wok888-dl-5kw-induction-wok

    Great exercise for your wallet, but in terms of cooking in a wok using traditional methods, waste of time and money. As soon as you lift the wok from the stove to toss the ingredients, the heat is removed from the pan. Refer to the wikipedia article for details.

    Or just get one of these for less than $100 - 67 MJ of pure fun:

    http://www.auscrown.com/page/shop/flypage/product_id/169/a/category/e/commercialcastironburners_duckbillburners

    Which is exactly what I suggested previously...

    Posted Saturday 31 Dec 2011 @ 3:26:36 pm from IP #
28. 

    Bushwalker
    Member

    One of these would be adequate for domestic:

    http://www.auscrown.com/page/shop/flypage/product_id/72/a/category/e/highpressurewokburners

    Posted Saturday 31 Dec 2011 @ 3:36:43 pm from IP #
29. 

    cava
    Member

    Bushwalker said:
    One of these would be adequate for domestic:

    http://www.auscrown.com/page/shop/flypage/product_id/72/a/category/e/highpressurewokburners

    This is a very good wok burner. I should know - I approved it for use in Australia.

    Posted Sunday 1 Jan 2012 @ 10:49:50 am from IP #
30. 

    dymonite69
    Member

    Bushwalker said:
    it will be wok by name but not by nature, you might as well use a frypan.

    Except that tossing stuff vigorously with a spatula in a fry pan tends to make a mess. With a quick flick you can toss stuff in a wok without it staying out of contact from the burner for very long.

    Posted Sunday 1 Jan 2012 @ 11:05:28 am from IP #

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