hybrid solar panel (photovoltaic and thermal)

by:Tunto     2020-03-23
I bought some photovoltaic cells some time ago (
6 \"x 3\", rebeccayi0904 from ebay, very good seller! )
Plan to build a PVpanel (
After reading a series of instructions on solar panels here! ).
When testing individual cells in the sun, it is found that they become very hot.
Then I realized that the photovoltaic board is only about 12% of solar power.
What about the rest?
Become hot (about 88%).
Maybe on the same surface, I think, people can take advantage of the power and heat of the panels. . . .
I will not repeat all the details about how to build the solar panel, and there are many other instructions for this (
Search tools are your friends! ).
I will give some basic information though. . .
Then pay more attention to the \"mixed\" nature of my panel (PV+thermal).
General Features :-about 0.
In the 5 m 2 area, the maximum radiation of 1 KW/m 2 and the efficiency of 12%, this should produce power up to 60 W. (
At the same time, it means it is possible to take advantage of the thermal energy of about 440 W! ). Materials:-
36 cells, 3 \"x 6 \".
Fee: approximately $150 from rebeccayi0904 (
Ebay, good seller! )for 80 cells (
36 for this panel). -
Aluminum back panel (
26 \"x 32\", I can\'t remember the thickness)
: About $10 in a sheet metal store. -
Small Volume bequest sil-
Pad 400, ebay is about $50 (
The seller can\'t remember)-
The hardware store\'s glass front cover is about $15.
Borders\'s aluminum rail, hardware store, is about $12-
25 feet \"about 1/4 of copper pipes, about $20 for hardware stores --some 2-
3 barrels of silicone filler-
Aluminum flux paste from McMasterCarr (
About $30 but you can buy a small amount and I only use 1/20 of the tub)-solder-
Search ebay for 12v pumps for \"12 v pump laser and cpu cooling\" for about $10.
Note: the aluminum paste is a very annoying material.
It contains fluoride and can cause you serious damage if handled improperly.
Read all instructions and material safety data sheets (MSDS)
If you don\'t have 100% confidence in being able to work safely, don\'t do that.
Figure 1: welding 1/4 \"(~0. 5 cm)
Flexible Copper Tubes for aluminum backplates.
The back panel is about 0. 80 m x 0. 65 m.
I used a tube about 7 metres long.
Make sure to bend the pipe with the right tool to avoid squeezing the pipe! The Al.
The plate is about $10.
About $20.
Photo 2: I think it is impossible to weld aluminum. Incorrect!
You need the right traffic.
I bought it from McMaster.
About $30. Notes: 1)
Buy a small pot, much more than I need. 2)
Be careful, this kind of thing is annoying: it has Fl and it is not recommended to breathe steam or touch!
Photo 3: my friend Martin is welding the receiver and the plate.
Please note that we work outside and the breeze is great and we use some protection! Photo 4: End-
Result: won\'t win the welding race but not bad for our first welding of aluminum. . . Photo 5: Close-
Start of welding work. . .
Can it be better?
Aluminum needs to be covered with some electrical insulator (
I\'m using bequest sil.
Pad 400, about $50)
Because the back of the photovoltaic cell is one of the most important components. Sil-
Pad is also a good thermal conductor but I think tar
Paper can also work and will be much cheaper!
Photovoltaic cells are 15 cm x 7.
5 cm, 36 cells will be used in this pane.
I\'m on ebay from rebeccayi0904 (nice! )
The price of 76 batteries is $150 (
1/2 for this panel).
Cells need to be connected in series (
How about your welding skills? )
Then I stick them to sil.
Use a silicone filler pad.
Note: There are only 0 photovoltaic cells.
20mm thick, it will break if you look too hard!
The electrical interconnect between rows is added (electrical bus).
Note that I cracked some of the batteries which will reduce the efficiency of the panel, alas! First test!
Just stick out the panel and connect a 12v halogen lamp and the panel will pump 16.
2 V, the light is very bright!
The open voltage is just over 20 v.
The short circuit current is about 2a.
It is in winter, so the sun is not very bright.
Figure 1: Test the water system.
Pay attention to the pump (
12 V, buy on ebay for $10)
Powered by half of the solar panels (
Generate ~ 9 v).
Plastic pipes are recycled from old medical conditions!
Figure 2: Water is circulating!
Cloudy today, only 4 V is generated for 1/2 of PV panels (
Should be over 9v on sunny days! ).
Photo 3: cool man in mirror :-)
Figure 4: The water cycles between the panel and the small cooler, and some volume heat will be done later to check the thermal output of the system. (
The sun is not enough today. . . )
Photo 1: insulation on the back.
I just stuck some foam plastic on the back with a silicone filler.
Photo 2: Details, try to keep the weather tight.
The cable goes through a hole in the aluminum frame and has enough caulking to keep things in place.
We finally have a sunny day!
I can do some testing.
Unfortunately, it will not be done until 4: 00 pm. . .
The sun is bright, but not the brightest.
Figure 1: The first day of the real test (May/5).
Half of the panel supplies some 12v halogen lamps.
This half panel offers 9 lights. 3 V at 1. 47 A (power = 14 W)
, Connect 2 lights, the voltage drops to 7. 9 V at 2. 69 A (power = 21 W).
Extrapolation of the entire panel, which will be at least 42 W of power (
Considering that the theoretical maximum value of this panel is 60 W, assuming the solar power is 1 KW/m2 and the efficiency of the photovoltaic system is 12%, it is not too bad to do this experiment at 4: 30 p. m).
The other half of the PV panel power the water pum, which makes the water cycle between the panel and the cooler.
The system has 3 kg of water.
Photo 2 and results of photo 3: May/5.
Given the heat capacity of water [4. 2 kJ/(C kg)]
It can be concluded that the maximum thermal power of the transfer is about 200 W (
Considering that the panel receives up to 500 W of solar power, it\'s also good! ).
Please note that I have ignored other possible heat transfer (cooler, etc).
See the following day\'s experiment. The max.
The temperature reaches 52 °c (126 F).
It\'s hot to touch!
Photo 4 and results of Photo 5: May/6.
The second day of the experiment
I used 3 kg of water in the cooler again.
Please note that I closed the pump at 94 minutes and the water started to cool (
In ~ Under the energy loss rate of 56w.
Look at the next picture.
I estimate that in the \"more stable\" area of temperature rise, the thermal power is about 210 W.
On this day, the solar flux is similar, noting that the power of the 2 lamps is almost the same as the previous day.
Please also note that connecting 3 lights in parallel will reduce net power: This is an important factor when designing a complete photovoltaic system and you need to optimize the IV operation point!
In the figure, a very high heating rate in the first few minutes may be a product of the use of cold water (
By the way: the temperature is around 24 degrees Celsius).
I turned off the pump in 94 minutes and the water began to cool (
In ~ Under the energy loss rate of 56w.
Please note that before the maximum temperature is about 52 °c (126 F).
Overall I was very happy with the results, but I did spend a lot more dollars than I expected! ! !
Is this a cost?
It remains to be seen to provide effective solutions for people\'s homes.
Ilike\'s idea of using solar energy as much as possible, which makes the surface area the most complete use (e. g. Roof of a home).
An additional advantage is that water reduces the temperature of pvcell and improves efficiency (or so Ihope).
Please comment if you find this description interesting.
Please comment if you have suggestions.
What other types of heat exchangers can be used?
I still have enough pvcell to make the second panel, but I would like to have a cheaper, simpler way to take advantage of thermal energy.
Any suggestions are welcome.
Please like, let me know if you decide to make a panel like this. THANKYOU. Carlos Wexler(carlos1w@yahoo. com)Note (
May/13/2010 has been added)
: Google search shows that there are obviously some business systems that use the same concept (
Use both electricity and heat in one package).
For example, see: they use air convection on the back of the panel (
Not water).
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