Tropical Fruit Forum - International Tropical Fruit Growers



Author Topic: Solar power generator for space heater  (Read 904 times)

Citradia

  • Sr. Member
  • ****
  • Posts: 313
    • USA/NC/Old Fort/6B
    • View Profile
Solar power generator for space heater
« on: August 14, 2016, 06:09:38 PM »
Hey, has anyone experimented with solar power heaters or solar power generator that could run a small space heater all night?  Brands, suggestions?

Pancrazio

  • Off Tropic
  • Hero Member
  • *****
  • Posts: 860
  • Florence, Italy, USDA 8
    • Growing fruits in Florence, and Pratovecchio, Italy
    • View Profile
    • FruttAma.it
Re: Solar power generator for space heater
« Reply #1 on: August 16, 2016, 08:39:14 PM »
Not any thought, but a comment.
Changing solar input to heat is very high in efficiency; in fact you ca go for a 90% efficiency easily (with a simple black cover you can be assured that almost all the solar radiation will become heat).
Transforming light to electricity, storing said electricity, and using it for heating,  has several losses in efficiency that will force you the use a comparatively high surface of solar collectors (expensive) and batteries (also expensive) to save few dollars of electric bill (of course, Iím still thinking to single enclosure plants).
I'm all for energy savings, but at this point it think that on the long run, probably, you would be happier (and could potentially save more $$$) if you managed to use sun directly for heating more than for electricity (to use for heating later).
I'm not by any means an expert in solar building, but those links helped me a bit.
Maybe they can be also useful for you who knows?
http://www.builditsolar.com/
https://web.archive.org/web/20120329185815/http://www.ece.vill.edu/~nick/solar/solar.html
https://energyfarms.wordpress.com/2010/04/05/solar-greenhouses-chinese-style/
Italian fruit forum

I want to buy/trade to get the following mango scions: Florigon/Rosa/Francis Hargrave. Avocado: Mexicola. Contact me in PM if interested.

Citradia

  • Sr. Member
  • ****
  • Posts: 313
    • USA/NC/Old Fort/6B
    • View Profile
Re: Solar power generator for space heater
« Reply #2 on: August 19, 2016, 08:53:22 PM »
Thanks for the reply and the info, Pancrazio!

LaCasaVerde

  • Member
  • ***
  • Posts: 148
    • pensacola
    • View Profile
Re: Solar power generator for space heater
« Reply #3 on: October 23, 2016, 12:54:25 AM »
Technically net metering would accomplish this if your solar kwhs produced exceeded your daily kwhs consumed. I have a 6.25kw solar array producing around 36 kwh per day. My home uses less than this so the extra would power a small heater though the night with no cost to me after investment.  Yes it is possible as Im doing it now. Depends on what you want to spend initially. or you can use this method in which I am also using which works just as well using solar in a different way.
 I converted my home completely to solar hot water using in parrallel solar hot water heating panels. I have seven that fill a 40 gallon hot water heater with 160 degree water in 4 hours.  My greenhouse will be suplementaly heated the same way using solar hot water panels which are 2x2 in size each heating a ibc water tote of 275 gallons. This will become a thermal battery and radiant  space heater at the same time for my plants.
Granted Im not sleeping beside the tote as Im assuming your runing a heater to keep you warm...

BajaJohn

  • Member
  • ***
  • Posts: 94
    • Mexico, Baja California Sur, Loreto, Hot Desert
    • View Profile
Re: Solar power generator for space heater
« Reply #4 on: February 19, 2017, 10:20:03 PM »
The problem is storing the energy to generate heat overnight. LaCasaVerde has one solution. There are others ways to store heat directly.
Other thoughts would be candles, a kerosene lamp or heater or even a tiny wood or charcoal stove using trimmings from your trees although you may need to rig a thermostatically controlled blower to keep the temperature in a good range.
As for solar electricity, as with all methods, you need to figure the energy you will need. I will assume that a 100w incandescent light bulb would fit your needs. If you burn it for 12 hours you will consume 1.2 kWh of energy, equivalent to 100Ah at 12 volts. That determines the battery you will need. It needs to be double the energy you will us - in this case 200 Ah - at a cost of around $600 for an appropriate deep cycle battery. Solar panels run around $1 per watt. If you get 10 hours of usable sun per day, you need a minimum of 120 watts. With losses and cloudy days you should at least double that. A 250 W panel would cost you $250. A 20 amp charge controller runs around $100 and a 300 W inverter to produce the 110 volts for the light bulb would run under $50. That is about $1000. The battery is the limiting piece here (other than usable sun) and is also the most expensive.
Prices are from Northern Arizona Wind and Sun (https://www.solar-electric.com) which also has an awesome online forum with many real experts to answer any solar power questions you may have.
« Last Edit: February 19, 2017, 10:23:50 PM by BajaJohn »

Citradia

  • Sr. Member
  • ****
  • Posts: 313
    • USA/NC/Old Fort/6B
    • View Profile
Re: Solar power generator for space heater
« Reply #5 on: February 20, 2017, 08:17:27 PM »
Wow. Thanks, Bajajohn. I was hoping for a small affordable solution for a few single-tree cold frames, but sounds like it's not simple or affordable, which is why nobody is using solar power for small greenhouses. I can't use candles or wood heater in a 6x6 ft greenhouse full of satsuma because it would all go up in flames fast.

Ilya11

  • Member
  • ***
  • Posts: 117
    • France, Paris region, Vaux le Penil, middle of Northern z8
    • View Profile
Re: Solar power generator for space heater
« Reply #6 on: February 21, 2017, 06:56:43 AM »
Probably geothermal heating is a more economical solution

http://ipm.uconn.edu/documents/raw2/html/660.php?aid=660
Best regards,
                       Ilya

BajaJohn

  • Member
  • ***
  • Posts: 94
    • Mexico, Baja California Sur, Loreto, Hot Desert
    • View Profile
Re: Solar power generator for space heater
« Reply #7 on: February 21, 2017, 12:40:48 PM »
You need a bigger greenhouse! I thought you were talking about enclosures for single plants but solar electric heating still seems a burdensome option.
There are solar water heater panels available that you could use to heat water in 55 gallon drums if you have the space. One example is https://www.amazon.com/EZ-37-Solar-Water-Heater-Heliatos/dp/B007F54PUY. You could also look into insulating your greenhouse - even a removable cover for nighttime.
Google insulated greenhouse kits and insulated greenhouse covering for more ideas.
A fine wire mesh box will isolate combustion as a fire precaution. There are also small kerosene, propane and solid fuel heaters available (5000 BThU / 2's) that are completely enclosed (http://www.go2marine.com/category/14757/marine-boat-heaters-for-boats.html) at around $600. The kerosene models use about 1 gallon per 24 hours but they may produce too much heat for you.

Millet

  • Moderator
  • Hero Member
  • *****
  • Posts: 2148
    • Colorado
    • View Profile
Re: Solar power generator for space heater
« Reply #8 on: February 21, 2017, 01:08:55 PM »
Australian researchers have developed a clear glass energy harvesting panel that generates power that can be used for lights, heat etc.  The clear glass panels have a great future in greenhouse construction.

http://www.freshplaza.com/article/171198/Australian-scientists-develop-first-clear-energy-harvesting-glass
« Last Edit: February 21, 2017, 01:11:15 PM by Millet »

Citradia

  • Sr. Member
  • ****
  • Posts: 313
    • USA/NC/Old Fort/6B
    • View Profile
Re: Solar power generator for space heater
« Reply #9 on: February 21, 2017, 08:31:57 PM »
Thanks for the links and info guys! Very interesting concepts.

 

Copyright © Tropical Fruit Forum - International Tropical Fruit Growers