I'm New to this

Options
System
System Posts: 2,511 admin
in Solar Beginners Corner #1
I have wanted a solar electric system but it doesn't make ecconomic sense, but I would like to do it anyway. My calculations say that the break even point is over 25 years. Tax rebaits don't help because I am retired with low income.

To keep my investment reasonable I am considering a group of series connected solar panels to obtain 220 volts to power a stand alone resistive heater that in my basement. I would not be using batteries or an inverter. My question is "Is this a reasonable starting point for a solar electric system?"

I understand that solar hot water is more cost effective, but I don't like the idea of the heat exchanger running antifreeze thru my household water supply.

Comments welcome

Dozer
· Share on Twitter

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Options
    Re: I'm New to this

    Welcome to the forum!

    You've already discovered the ugly economics of solar electric. :cry:
    The panels are probably the most expensive part. Couple that with the difficulty of switch high DC Voltages and the inefficiency of electricity for heating things and you see your plan is probably not the best way to spend your money.

    If you want solar water heating, look in to building a "direct" solar hot water heater. Have a look at some of the DIY projects here: http://www.builditsolar.com/

    If you want to experiment with solar electric, consider some sort of direct DC low Voltage system, such as security lights perhaps.

    In my opinion, putting up 240 VDC worth of panels to feed a standard electric water heater would not be a good way to spend money.
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #3
    Options
    Re: I'm New to this

    And, I have a thread going (not organized yet) with lots of information and links to various solar electric, solar thermal, and other projects... Take a look through them and see what strikes your fancy.

    Working Thread for Solar Beginner Post/FAQ

    If I was looking for projects... I would start with conservation, look at solar thermal (lots of plumbing and pump related stuff--but does lend itself to DIY projects), and a small off-grid solar PV system that supplies enough power for an emergency (small fridge/freezer for medicines) plus a backup genset like the Honda eu1000i or eu2000i with stored fuel (gasoline, propane, diesel, natural gas--whatever makes sense for your home/area) for backup.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • zeuspaul
    zeuspaul Solar Expert Posts: 59 ✭✭✭✭
    #4
    Options
    Re: I'm New to this

    220 volts seems a bit scary to me.

    There are water heating elements designed as diversion loads that thread into standard electric hot water heaters. They are generally in the 12 to 48 watt range. It wouldn't make economic sense but you could make an electric hot water heater.

    I have also contemplated using raw PV to start playing as you don't need batteries or inverters. I bought a 135 watt panel and it is sitting in the garage waiting for me to decide the next move.

    I think I'll go for a more traditional off grid system with a battery, battery controller and an inverter. With 120 volts AC I can run a small 150 watt refrigerator ( I know I need more panels) and a waterfall pump. Much more fun and interesting than heating.

    Zeuspaul
    · Share on Twitter
  • AntronX
    AntronX Solar Expert Posts: 462 ✭✭
    #5
    Options
    Re: I'm New to this
    dozer wrote: »
    ...My question is "Is this a reasonable starting point for a solar electric system?" I understand that solar hot water is more cost effective, but I don't like the idea of the heat exchanger running antifreeze thru my household water supply...

    This is almost silly. What's wrong with heat exchanger and antifreeze? Afraid it will leak into water supply? That's close to impossible. With PV you are spending 4 times more money for a system 3 - 5 times less efficient. You can increase the efficiency of your water heating idea by 3 times by installing heat pump water heater and grid-tie based solar setup. Then you get additional 20 - 40% better solar harvest amount because of MPPT feature in grid-tie inverter. And with grid-tie you get 30% rebate off your (or your working family member's) income tax, plus possible local monetary incentives as well.
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #6
    Options
    Re: I'm New to this

    Also, the antifreeze used is usually a non-toxic type called propylene glycol.

    Now, I would look at a drain back type system for my home as the antifreeze is not cheap and does have to be replaced every 5 years or so (from what I understand).

    Some people still use a drain back type system for even very cold areas--But that may not work for you (waste of water, won't collect heat until it warms up some during the day).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #7
    Options
    Re: I'm New to this

    Using PV to resistance heat water to capture solar energy is far and away the worst use of PV $$ and energy. PV will be lucky to Capture ~15% of the solar energy, and by the time you convert that into heat it might be 5%. A Solar hot water hot water heater can capture way over 50% of the energy at way less cost.

    So looking at it this way, why spend 4 times as much for 1/2 as much gain?

    If you want to save money or do a project, consider doing energy conservation projects instead. Your dollar will go way further. For example $1000 spent on insulation will pay off in a matter of a few years if not a few months depending on the project and your location.

    Tony
    · Share on Twitter
  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #8
    Options
    Re: I'm New to this
    dozer wrote: »
    To keep my investment reasonable I am considering a group of series connected solar panels to obtain 220 volts to power a stand alone resistive heater that in my basement. I would not be using batteries or an inverter. My question is "Is this a reasonable starting point for a solar electric system

    Nope.

    220v AC is not scary. 220v DC is a defibrillator looking for a heart to grab hold of.

    To get 220vdc, you'd need a bunch of panels. Half a dozen or so depending on the panel voltage.

    You could buy one less PV panel and buy a charge controller and battery instead and have a more useful system.

    Of all the things you can power with solar electric - heating is probably the worst.

    If you want heat - the best plan would be solar hot water (even a simple one that only heats water not anti-freeze) and/or solar hot air (hot boxes are simple and cheap) and then maybe use a small solar electric system to power the pumps and fans (though, it would a LOT cheaper to power them off the grid).

    Solar heating is really cheap. Solar electric is really expensive.
    · Share on Twitter

Categories