Author Topic: Fresnel Water Heater/Boiler  (Read 2457 times)

0 Members and 1 Guest are viewing this topic.

My name is AL

  • Newbie
  • *
  • Posts: 19
Fresnel Water Heater/Boiler
« on: March 31, 2008, 12:25:23 AM »
I have a big Fresnel lens scavenged from a 42" LCD Projection. It is not the clearest one I have seen, but it should do something. I want to focus the light on a section of water filled copper tubing. One end of the tube will be in a cold water bucket, the other to a hot water storage bucket. The theory is that the heated water will rise out off the tube and into the storage bucket. The water will be replaced from the cold side. I may need some sort of check valve to keep the hot water from pushing back into the cold. Think of how a coffee perkolater works. I think it would produce a decent amount of water over the course of the day. It could be used to sanitize the water or use the water for heating purposes. It will ofcourse need a tracking device or heliostat. Any one want to jump on board with this experiment?
« Last Edit: March 31, 2008, 12:25:23 AM by (unknown) »

coldspot

  • Hero Member
  • *****
  • Posts: 839
  • Country: us
Re: Fresnel Water Heater/Boiler
« Reply #1 on: March 30, 2008, 07:27:45 PM »
Al-

Cool project !!   :)

 I've got plans for one using the big lens from

one of those lite magnifier on a spring loaded arm.

"a tracking device"

 RedRok sells a nice led one for about $35

"check valve"

 I'd think so, I've got some from siphon pumps from the Dollar store that I got just for the clear plastic hoses they have in them.(the hose is UV reactive) LOL  :)


 Anyway have FUN and post about it!!


:)

$0.02

« Last Edit: March 30, 2008, 07:27:45 PM by coldspot »
$0.02

spinningmagnets

  • Hero Member
  • *****
  • Posts: 599
Re: Fresnel Water Heater/Boiler
« Reply #2 on: March 30, 2008, 07:45:53 PM »
Lots of good ideas like this over at "builditsolar.com"


"Thermosiphon" means if configured correctly, the heated water will rise, causing a natural circulation in the loop without a pump.


If you were to find an old water heater tank, you should insulate the outside and set it up so it stands vertically. Build a set of vertical heat collection pipes alongside the tank. Join the tops of the collector pipes and connect them to the top of the tank, and also join the bottoms and connect them to the bottom of the tank.


If there is some air in the storage tank (for heat expansion) the collector pipes must be full of water and the upper outlet pipe must empty into it under the storage water top level for it to circulate without a pump.


It would be worthwhile to box in the heat collection pipes, and cover the front with glass, perhaps an old glass door. Of course, set the fresnel lens at whatever distance provides the best heat focus.


If you connected the collector to the tank with flexible hoses, you could make a tracking mechanism, so the collector follows the sun.


Perhaps use a fixed collector with two reflecting panels on the sides like a funnel, and have the fresnel lens track the sun. Best of luck, and have fun.

« Last Edit: March 30, 2008, 07:45:53 PM by spinningmagnets »

My name is AL

  • Newbie
  • *
  • Posts: 19
Re: Fresnel Water Heater/Boiler
« Reply #3 on: March 30, 2008, 08:18:18 PM »
I read once about a tracker that used two small solar cells wired to a motor. As the sun moves west it induces more volts in one of the panels, making the assembly rotate untill in reaches equal voltage in the two panels.

I like the idea of a thermal siphon. You could use a conventional Radiator in your house for a storage tank, just let the water cycle through the rad and back to heater. I planned on 1/4" or 3/8" copper so the idea is the water will be really hot, maybe not lots of it. I was not thinking of a hugh collector, maybe something like 2 " square. Those big fresnels can melt pennies so it should heat a small stream of water nicely. Whatch Think?
« Last Edit: March 30, 2008, 08:18:18 PM by My name is AL »

DanG

  • Hero Member
  • *****
  • Posts: 980
  • Country: us
  • Twin Cities Minnesota
Re: Fresnel Water Heater/Boiler
« Reply #4 on: March 31, 2008, 05:33:20 AM »
Image Dimensions: 33.57" x 25.24"

Image area: 847.31 sq. in. - 5.9 ft² or .55m²


A very good solar collector will capture 900btu per square foot per day;

5.9 x 900 = 5310 Btu per day


A borderline collector will capture 600 Btu per ft² per day



  1. 9 x 600 = 3540 Btu per day
  2. Btu heats 43 gallons of water by 10 degrees; or melts 24.7 pounds of ice.
  3. Btu heats 64.7 gallons of water by 10 degrees; or melts 37.05 pounds of ice.


...without losses anywhere past the Fresnel lens...


17.7 Btu per minute = one gallon raised two degrees Fahrenheit during the 5 solar peak hours daily...


Anyhow - what the lens can do quickly is start a fire. Be very careful about shielding it to keep something from getting near the focus that could burn...

« Last Edit: March 31, 2008, 05:33:20 AM by DanG »

My name is AL

  • Newbie
  • *
  • Posts: 19
Re: Fresnel Water Heater/Boiler
« Reply #5 on: March 31, 2008, 12:40:24 PM »
So your saying in theory this would raise one gallon of water 2 degrees every minute? 120 degrees an hour for one gallon? Is that Celcius or Farhenhight?

I wonder what BTU's a 400 square foot room would need in the middle of winter, lets say average heat loss. I live in Southern Ontario Canada.

Just so I understand how long would it take in theory to boil one US gallon of water from 0 degrees, (0 to 100 degrees) with this lens?
« Last Edit: March 31, 2008, 12:40:24 PM by My name is AL »

WindythePoo

  • Newbie
  • *
  • Posts: 3
Re: Fresnel Water Heater/Boiler
« Reply #6 on: April 02, 2008, 04:54:24 PM »
Is it? This is very interesting. I have an old Radiator in my living room, I may now have a use for it. So your saying it will flow a small amount of very hot water? It may take a bit to get the rad up to temp, but once you do that would be great! How are you coming along with this??? Keep up the good work.
« Last Edit: April 02, 2008, 04:54:24 PM by WindythePoo »