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Reduduction of Electricity Use

Discussion in 'Home Power and Microgeneration' started by Alan Combellack, Feb 6, 2006.

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  1. 1. I need to greatly reduce the cost of powering, including heating, of an
    old log farm house which is entirely powered by mains electricity at
    present. It is located in Canada.
    2. I know I can get considerable improvement by increasing insulation and
    air sealing and including heat transfer from outgoing and incoming
    ventilation air. This should pay for itself in a very few years, depending
    on who does the necessary work.
    3. The next best solution is to add a fairly large solar panel to heat water
    when the sun is shining. I might also use heated air spaces on an outside
    wall. This is quite expensive but should still pay for itself in a
    reasonable period.
    4. We will always require access to a reliable supply of electrical power,
    say 24 kWh per day if the space and water heating is done from the solar
    panel and hot water store. This might be supplied by PV panels mounted with
    the hot water panel so as to cool the PV cells and improve efficiency
    somewhat. This is very expensive and at present is not economically viable
    for me while electricity prices are so low. The usual assumption is that
    batteries will have be used to store electricity for night time use and to
    carry over sunless periods. The PV and battery costs will be very high if
    this is done and at best might pay for itself in 20 years or so. Sometime,
    probably fairly soon, energy prices will increase a lot so such a system
    will become more viable. Hopefully prices for PV will reduce as demand
    increases. I don't want to wait for this, however.
    5. Energy can be quite economically and efficiently stored in a well
    insulated tank. Inevitable leakage of heat can be directed to assist in
    space heating when required so is not entirely wasted This is actually
    comparable to lead acid batteries in terms of volume and weight but is much
    cheaper than batteries. We could have a couple of thousand gallons of
    water, or more, heated to, perhaps, 125 degrees F. this can provide the
    space and domestic hot water quite nicely. My problem is figuring how,
    other than PV, I can use this source of heat to generate one kW of 60 Hz
    power. I see claims that Stirling and Sterling motors can do this fairly
    efficiently but am rather sceptical about this since the claims have been
    around for several years and have not yet become widely used. Can anyone
    point me towards such a machine which I can buy at a reasonable (<$2000)
    price and which has a proven performance record?
    If you wish to email remove the obvious bit and replace the first "a" with
    "r."
    Thanks.
    Alan C

     
  2. SQLit

    SQLit Guest

    No offence Alan but do you have a clue how many solar panels it will take to
    get 2000 gallons of water to 125F in Canada?
    I live in Phoenix and my old house had 1 4x10 panel and a 80 gallon water
    heater. 4 months out of the year the electric back up ran. 2 months a year
    the electric back up ran most of the time.

    In my opinion mixing potable and heating water is a MISTAKE.

    Stirlings do work, and no your not going to find one for $2k. My local
    electric company has 2 solar sun flowers and stirling generators. I have
    heard that for the 25 kw that they produce, the cost for the installed set
    up was over a million US dollars. Probably why they only have 2 in their
    test area. http://www.aps.com/my_community/STARtour/default.html?seq=1

    stirling direct page
    http://www.aps.com/my_community/StarTour/default.html?seq=15

    I go through the place every time they offer tours. It is a trip what they
    are doing.
     
  3. Those are a little more "active" than I think he means. I think he really
    means the solar lean-to type of concept. I've used both SolarWall and
    CanSolair - scrapped the SolarWall. SolarWalls will raise the ambient
    temperature ~10C - on a still day, and do nothing on a windy day. Since
    it's getting it's air from outside it doesn't do much for a home - but
    works great for a barn or warehouse. The CanSolair, otoh, is heating
    interior air. It might actually be less efficient than the SolarWall, but
    works better for a home.
    Ditto. First thing is to get your energy use _down_.
    Definitely.
     
  4. Thanks. I had hoped it wasn't so. I'll certainly look into the solar flat
    panel space heating. I think Nick has done a lot of work on this. Looks
    feasible for me. I still like the idea of warm water used to replace lead
    acid batteries. Not much bigger or heavier and much cheaper. If only there
    was some way to upgrade the "quality" of the energy stored!!
    Alan C
     
  5. Thanks to everyone who replied. All good, thoughtful and useful comments
    which I greatly appreciate. I have a lot more to think about now.
    My present power charges are over $4000 per year and I use about 3.7 kW
    continuously, 88 kWh/day on average; 55 in summer and 121 in winter, so
    money is a serious concern for me although "going green" has a certain
    appeal. I don't ever expect to get completely off the grid.
    Clearly I must continue to improve insulation etc. a lot first and see
    where we go from there.
    I have done a lot of calculation about hot water storage systems and I
    reckon I would need a fixed, sloped panel of about 600 square feet and a
    well insulated tank of about 100 cubic feet (624 UK gallons). This would
    require that I make a separate building (which will also need heating) to
    hold the thing up but I do have a suitable site for it. I could use it as a
    garage, storage and, perhaps, greenhouse as well which spreads the cost a
    bit and increases, I hope, the house value. As some of you said this isn't
    going to get cheaper so if I do something then it must be done as soon as
    possible.In the meantime would someone please invent some means of turning
    low grade heat into electricity reasonably inexpensively :-}. I have tried
    but don't seem to be getting anywhere
    Thanks folks.
    Alan C
     
  6. Jim Baber

    Jim Baber Guest

    Jim Baber comments:
    Since you are on the 'Mains' now, you are on the commercial grid,
    and do not need to incur the cost and complexity of batteries at all.
    The only need you might have is to provide backup for the grid if the
    commercial power should fail. This can be useful if you need it for
    medical needs, or common long outages (storm damage etc.), but normally
    it is an expensive extra.

    You probably just need to be installing a grid tied system. These
    systems effectively use the grid just like a battery and store any power
    you do not use during the day (meter runs backward) and you then use
    power the utility generates at night, during bad weather, or when your
    PV system is simply not producing enough for your immediate current
    needs. For example when starting large motors like an air-conditioning
    compressor, or well pumps.
     
  7. Jim Baber

    Jim Baber Guest

    They do and that is what you pay for, but correcting a poor power factor
    reduces the amount of power (watts) you need. In my own case the year
    before I corrected my power factor for the entire house we used 25,999
    kWh (from the bills). After I installed the correction capacitors that
    my total usage was reduced to 17,869 kWh for the following year. We had
    no other significant changes in our life style or equipment around the
    house.

    I believe the correction of the power factor reduced our power
    consumption by about 31%

    If you were a large commercial or industrial account your contract would
    even allow the utility to charge additional penalties for power factors
    worse than 0.85.
    No, you have to pay the meter, they will supply any additional power to
    compensate for you poor power factor, but, you do pay for it. In fact
    today in California your utility company makes very little electricity,
    they are primarily just delivery and billing agents. And thusly, the
    utilities don't care how much you use, unless they have to build new
    transmission lines.

    Note: all those local solar systems (like mine) just help the utilities
    to avoid building new transmission lines, but they do charge all you non
    generating users for them even when you use my surplus that I generated
    next door.

    As you may be aware from my other posts I do have a large (for a home)
    10 kWh PV solar system. That first year I had the system my own
    generation dropped my PG&E bill down to a total of about $450. The 2nd
    year our own generation produced about the same amount of power, but my
    PG&E bill dropped down to a $400 credit (which I lost), but I only had
    to pay them a required $74 minimum standby & service charge. These 2
    annual bills were both a lot better than the $5,050 I had paid the year
    before I put in my solar system.
     
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