I Built a SOLAR FREEZER that reaches -48°C ❄️ DIY — Transcript

Full transcript

1. 0:00Can the sun's heat produce cold?
2. 0:02We've replicated a miniature refrigerator capable of cooling to -48° Celsius
3. 0:08using the sun's heat.
4. 0:10Stay tuned to the end to see how it works.
5. 0:19With this copper tube 1.6  meter long and 1/4 inch in diameter,
6. 0:24we'll make a condenser.
7. 0:26Using a can of paint, we'll shape the tube into elongated coils.
8. 0:44We should separate the coils  slightly to allow for natural ventilation.
9. 0:54We'll use this copper tube 3.6 meters  long and 1/4 inch in diameter to make the evaporator.
10. 1:00We'll also shape this tube, but this  time into perfectly cylindrical coils.
11. 1:10Next, we need a copper tube 22  mm in diameter and 200 mm long.
12. 1:18We need to place these two end caps on the ends,
13. 1:21but first we'll mark their centers to drill holes.
14. 1:34We'll use a 1/4 inch drill bit to drill them.
15. 1:45We must thoroughly clean all the metal shavings
16. 1:47from inside all the  tubes we're going to use.
17. 1:55We'll remove any burrs from the holes.
18. 2:04Later, we'll solder the plugs.
19. 2:10With this 3/8 inch 48 mm long tube,
20. 2:14we're going to make a non-return valve.
21. 2:17This will be our gas recharge valve.
22. 2:20We must unscrew the core
23. 2:22and remove it to prevent it from burning during the soldering process.
24. 2:26We use the plug itself to unscrew the core.
25. 2:35We place both pieces  in a holder with metal clamps
26. 2:44and we proceed to braze it.
27. 2:46This type of brazing uses map gas in the torch
28. 2:50and a filler rod containing copper and 5% silver.
29. 2:57Once brazed, we make a mark on  this end to drill it with a 1/4 inch drill bit.
30. 3:10Again, we file to remove any burrs.
31. 3:18And we solder this small quarterinch tube  by inserting one end into the hole.
32. 3:33With fine sandpaper, we  clean the ends to solder them later.
33. 3:40Now we must join the condenser to the  tube that will be the tank of our refrigerator.
34. 3:48We must solder the joints.
35. 3:59Now we bend this end of the evaporator.
36. 4:07We cut off the excess here.
37. 4:18This end will be the seat for the steel  ball that will form part of the non- return valve.
38. 4:24To ensure the 6 mm ball fits  perfectly, we'll counter sync the end of the tube.
39. 4:35This way, the ball makes a perfect seat, preventing the gas from flowing back.
40. 4:45We insert the ball into the valve body
41. 4:55and proceed to weld it to this end of the evaporator.
42. 4:59We check that the ball moves freely inside the valve.
43. 5:03Before connecting the evaporator to the receiver tank,
44. 5:06we must blow compressed air into the  inside of the pipes to remove any impurities.
45. 5:13Once clean, we join  them as shown and solder them.
46. 5:30We bend the end of  the condenser at a 90° angle.
47. 5:36We cut off the excess, ensuring  the two tubes are facing each other.
48. 5:47This thin tube 17 cm long  and with an inner diameter of 0.6 mm
49. 5:57will be the capillary tube.
50. 6:06We coil it into a loop.
51. 6:07We shape the ends to connect them to our refrigeration system.
52. 6:16Using pliers, we crimp the ends  of the tubes to secure the capillary tube,
53. 6:20being careful not to crush it.
54. 6:28After this, we solder the capillary  tube to the ends of the tubes.
55. 6:35Once soldered, we replace the core  of the gas charging valve.
56. 6:40We tighten it again using the  groove in the cap itself as before
57. 6:48and we replace the cap to prevent dirt from  entering the refrigeration circuit.
58. 6:57Before continuing, we will clean  the carbon from the solder with a rag.
59. 7:01And now using ultra fine sandpaper,  we polish the circuit tubes.
60. 7:22To make the solar collector, we  bent these three tubes using this 120 mm diameter mold.
61. 7:30We'll also use three 165 mm long tubes.
62. 7:34Like all the other tubes, they are a 1/4 of an inch in diameter.
63. 7:38We'll also need four 50 mm tubes
64. 7:46and two copper clamps.
65. 7:51We place all the semicircles on this iron template so we can weld them vertically.
66. 8:04At the top, we weld this tube.
67. 8:16And we weld another  tube to each of the lower ends.
68. 8:30This frame will hold the curved mirror  that will collect the solar energy.
69. 8:41We secure the frame with clamps.
70. 8:59We use this 167 mm long, 22 mm diameter tube
71. 9:05to weld the clamps in place.
72. 9:12We also flatten one end of  each of the smaller tubes.
73. 9:28We place the tube with the  clamps in the exact center of the frame
74. 9:36and secure it with rods and two clamps.
75. 9:46We position the four tubes connecting  the frame with the clamps on the central tube.
76. 9:53And we soldered everything together.
77. 10:09This is how it all turned out.
78. 10:11Now we can remove the central tube.
79. 10:22We sanded the entire structure well  to enhance the copper's shine.
80. 10:34Here we have a 2 mm  thick sheet of acrylic mirror.
81. 10:40Since it's acrylic, we can heat it  with a heat gun to mold it without breaking it.
82. 10:48This was our third attempt. The previous ones broke.
83. 10:54Once the mirror was molded, we pressed  it into the solar collector frame.
84. 11:13This frame has the capacity to collect the sun's rays
85. 11:16and concentrate them in the  center along the length of the tank tube.
86. 11:30We're going to install our solar  cooler on this wooden base.
87. 11:39We'll use clamps to hold the device in place.
88. 11:59We position it on the clamps
89. 12:03and tighten them with pliers.
90. 12:12Now we're going to charge it with  refrigerant through the charging valve.
91. 12:18We'll use isobutane gas, the  same kind used to refill a lighter.
92. 12:25We press the nozzle against the valve  and inject the gas.
93. 12:30Then we extract it completely.
94. 12:32And we repeat  this operation three or four more times.
95. 12:39This purges all the air that  might be inside the line.
96. 12:45This ensures that  only isobutane is inside.
97. 12:52We replace the cap
98. 12:56and attach the solar concentrator.
99. 13:04This design will allow us to orient  the concentrator towards the sun.
100. 13:14How does this device work?
101. 13:18Most of the refrigerant gas is housed in this tank.
102. 13:22When the solar collector captures sunlight,  it concentrates it in the tank.
103. 13:26This causes a significant temperature increase  making the gas expand.
104. 13:31But the gas cannot circulate in this direction
105. 13:34because the ball inside this valve will prevent it from flowing to the evaporator.
106. 13:39Therefore, the gas will only  circulate in this direction.
107. 13:42It will circulate inside the condenser
108. 13:45and accumulate a  high pressure due to the obstruction
109. 13:48caused by the enormous narrowing of the capillary tube.
110. 13:51The gas will flow through this narrow conduit
111. 13:54and upon reaching the evaporator will  experience a significant pressure drop
112. 13:58causing massive cooling of the conduit.
113. 14:01The gas will pass through the entire evaporator freezing it.
114. 14:05When it reaches the non-return valve,  the internal pressure will push the ball upwards,
115. 14:10allowing the gas to flow back to the  receiver tank, restarting the refrigeration cycle.
116. 14:22We will conduct the tests in  an urban environment
117. 14:25where the sun doesn't even shine very intensely.
118. 14:32We adjust the collector to receive the maximum amount of sunlight.
119. 14:37For our system to start working,
120. 14:39we only need the receiver  tank to reach a temperature of about 60° Celsius.
121. 14:45We have sped up the video slightly  to show the freezing process more clearly.
122. 14:50After a few minutes, we see how frost has completely covered the capillary tube
123. 14:54and the evaporator.
124. 14:56Even in sunlight with  a temperature of over 30° Celsius,
125. 15:00we get ice at a very low temperature.
126. 15:03It's real ice. You can see it melting between my fingers.
127. 15:07How is it possible for heat to produce ice?
128. 15:10It's very simple.
129. 15:12The sun's heat is the greatest source of energy we know.
130. 15:15And this machine converts that energy into cold.
131. 15:18With this laser thermometer, we observe how the  evaporator temperature has dropped to -48° Celsius.
132. 15:26That's the temperature of the North  Pole in winter.
133. 15:30Since it's hot, let's cool a beer.
134. 15:36After a minute, we see water condensation  surrounding the entire can due to the cold.
135. 15:44More and more ice is  accumulating in the tube.
136. 15:59The surface of the  can has already reached -13° Celsius.
137. 16:06The can being in contact with the evaporator  has given up some of its heat.
138. 16:11And for that reason, the evaporator's temperature  has now increased.
139. 16:16If we clean off the layer of frost,
140. 16:18we get a reading on its surface of 34° below zero.
141. 16:23As we can see, the temperature has risen slightly.
142. 16:29It's time to enjoy an ice cold  beer under the blazing sun.
143. 16:38Let's try it with a bottle of  water, which freezes at 0° Celsius.
144. 17:00We speed up the video. And after a few minutes,  we see the water freeze completely.
145. 17:08As it expands, the bottle gets a little stuck in the coil.
146. 17:18Our portable cooler has been  in the sun for over an hour
147. 17:21and is still cooling as well as it did at the beginning.
148. 17:29It's still at 47° below zero.
149. 17:35If we turn the solar collector so it's  not in direct sunlight,
150. 17:39the gas stops flowing through the pipes.
151. 17:42The temperatures of the  two coils equalize and the evaporator defrosts.
152. 17:51We hope you enjoyed this invention.
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155. 18:01Thanks for watching.