solar heat collectors -Does solar thermal work in very cold temperatures? There is heat in light!

July 26, 2014 – 12:24 am

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  1. 8 Responses to “solar heat collectors -Does solar thermal work in very cold temperatures? There is heat in light!”

  2. Ed Hammerly of New Jersey renewable energy forgot to mention some important
    points in his video on Sunday Feb 03.

    I find that most green energy folks always forget to mention reality and
    how it actually works, especially when talking about solar water heating
    systems or electric cars in cold climates with one to two hour commutes in
    rush hour traffic like in Chicago when it is 10 F – Fahrenheit or colder
    with the heater running full blast.

    Most home hot water heaters are set at 120 F for a reason. Legionella
    bacteria (i.e., that can cause pneumonia and mild flu like illness called
    Pontiac fever) can grow in water temperature between 68 and 122 F. And,
    most people like to take showers that are around 100 F. My wife prefers 105
    F. We would be very unhappy having to take showers at 75 F to 89 F. Our hot
    water heater is set at 140 F, which is probably 20 degrees above average.

    Ed indicates that the water tank is 80 gallons. At 12:30 pm, the temp in
    solar collector is at 138 F, the temp in the tank at the top was 79.5 F,
    middle 64.4 F, and bottom 62.8 F. By 2 pm, the temp in the collector is
    138.9 F; the water at the top of the tank is 88.3 F, in the middle 72.9 F,
    and at the bottom of the tank 72.0 F. By 3 pm, the collector is at 115.9 F
    (a loss of 23 degrees F or 16.5%) the top of the tank is 88.2, the middle
    79.0 F and the bottom 78.6 F.

    Ed then states that we have gotten a free tank of hot water; he should have
    said warm water (80 F to 85 F) and stated the actual cost. It was not
    free.
    http://energy.gov/energysaver/articles/solar-water-heaters

    “Doing the Math on Solar Water Heaters”

    A solar water heating system cost from $8,000 to $10,000 for households
    with four to five people.

    Assuming an average life of 20 years, that is from $400 to $500 per year,
    before maintenance. The average energy bill for a single family home is
    about $2,200 per year. Of, this 14%, or $308 per year, is spent to heat
    water.
    http://www.americanthinker.com/2012/06/doing_the_math_on_solar_water_heaters.html

    Ed also assumes that no one is taking a shower in the afternoon on Sunday
    or washing clothes. An average 10 minute shower can use from 25 to 50
    gallons depending on your shower head. A fully loaded washing machine uses
    25 to 35 gallons. A dishwasher uses about 3 gallons. If you are running
    these after 3 pm in the afternoon, you will run out of warm water.
    http://askville.amazon.com/gallons-water-average-10-minute-shower/AnswerViewer.do?requestId=2548818
    http://homeguides.sfgate.com/many-gallons-water-average-washing-machine-hold-full-80612.html

    Ed also forgot to show up what the temperatures in that 80 gallon water
    tank were at 6 pm or 8 pm, 10 pm or 6 am the next morning. My wife and two
    children take long showers before going to bed at around 10 pm. Sometimes,
    my wife and I use the about 50 gallons in our whirlpool tub in the master
    bathroom in the master bedroom. We have a 75 gallon hot water tank that
    works wells, which reheats sufficient amounts of water for all those
    activities.

    Ed forgot to mention that if you do take showers at night or in the
    morning, you will need a back-up water heating system (i.e. gas or
    electric) unless you like taking cold showers.

    Anyway, I have just explained the reality of solar water heaters in cold
    climates. 

    By George Lewis on Jul 26, 2014

  3. yea. would not work here. not much sun light, and -numbers in temp.

    By Mike Warren on Jul 26, 2014

  4. Cool, I’m all about conservating and renewable energy. I’m planning to do
    this myself once there are budgets for it.

    By Chue Hang on Jul 26, 2014

  5. great, I would consider solar PV too. Both continue to come down in price.

    By the43k on Jul 26, 2014

  6. It should work, just not as much obviously…

    By MrEnergyCzar on Jul 26, 2014

  7. We get as low as – 40 degree here with very little sun lights in Minot ND.
    Would there be any benefit?

    By Chue Hang on Jul 26, 2014

  8. The snow and mountain images I posted in this video are from Antarctica. As
    long as you followed the design parameters for you specific location, it
    would work. Keep in mind, the light that lands on you traveled millions of
    miles through space. It can surely handle -40 degrees, ;)

    By the43k on Jul 26, 2014

  9. By Alex Xu on Jul 26, 2014

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