@ss7406 They are more effective than flat plate collectors in cloudy weather, but bear in mind there is not a lot of heat to collect in diffused light.
there was a article in the late seventies that used the evacated tubes with a slight charge of co2 gas to increase the temp of the inside tube. the whole system was a compressorless air cond system. and a few years later the pyrex tubes were mirrored in the 180 back side to increase the heat even more. i built a system but used it to heat water and was impressed that the water would get to 210 degrees in a solar day. panel was 2.5 x 4ft, and heated a 30 gal barrel.
@richallenmusic Unfortunately, these tubes have yet to be put into service- they are waiting for my procrastinating friends to install a HX water heater, so I can install the panels. However, I have made some extra heat pipes that I use for demonstrations, and they are still working fine.
Thanks. Is there a ratio for the pipe volume to the fluid amount needed . If the pressure is rising in the tube does it self adjust the temperature at which the phase change takes place so their is always both liguid and gas. Could it all become gas at extreame pressure?
@bscfrnd1 I only know to use about 8cc for the 46" x 3/8" pipe I used, maybe you could figure from there. Yes, it could all become a gas at higher temps, that's why it's important to not use too much acetone, and normally the manifold will be removing the heat, avoiding pressure buildup.
@bscfrnd1 The glass tubes are called evacuated tubes because they have a vacuum pulled in between the inner and outer tubes when they are manufactured. IOW, most of the air is evacuated from the small space between the two tubes when they are formed. They may or may not be then used with heat pipes, which are the metal pipe installed into the evacuated tubes to move the heat captured by the tubes out and into a manifold.
@ebutuou123 A heat pipe is a closed tube with a small amount of working fluid inside. When sufficiently heated, the fluid boils, and rises to the cooler top of the tube where it condenses and gives up the heat it took to boil it. This is called a change of state, and is an efficient way to move heat. There is more detail to it, but that's a general overview.
@ebutuou123 Google it, but its like a vacuum greenhouse that heats a copper pipe, highly efficient and very dangerous in hot climates, handle with care and install a professional geyser, u can save 1000's
hi,my final year project is about heat pipes in solar thermal system..you know where we can buy one of this pipes just for experimental reasons! thanks u!
Sorry for being dumb but.... what do you do with the hot end that sticking out, and why does the copper tube not explode with the heat since you have sealed both ends?
@lezbriddon The hot end goes into a manifold that liquid flows thru to transfer heat to the domestic water. If you put too much acetone into the heat pipe, it could create too much pressure, but instead of exploding, it would separate at a soldered joint, and take off like a rocket. I have experienced this.
Sure, as long as the heat pipe is angled so the liquid will run back down it. The problem with simple parabolas is they need to track, check out compound parabola solar collector at fossilfreedomDOT com
Can you please tell me where you purchased the evacuated tubes and copper netting? What about using a glycol liquid instead of the netting? Thank you so much for sharing.
Adding a lot of liquid like glycol to the collector would hurt performance, low mass collectors are best. Copper scrub pads are available lots of places, grocery stores, Wal Mart, hardware, etc. Search "evacuated tubes" for sources
Can you please clarify what eactly is the nipple end of the tube, you call it a 6" riser? Is it hollow or solid? Also is there a vacuum only in the copper tube or are you pulling a vaccum in the glass tubes as well? Brilliant info thanks you so much for sharing!
It is a standard plumbing part, it's called a stubout, plumbers use it when roughing in new plumbing. It is a 6" (also comes in 12") piece of 1/2" copper tube, with one end sealed shut. The glass tubes have a vacuum in between them, you cannot make the evacuated tubes, only the heat pipe.
I would like to build this and was wondering if you would show installing the baby bottle nipple and where could i get glass tubes if i cant reclaim old solar systems. do you think florescent light tubes would be strong enough to use.
Installing the nipple just involves cutting the tip off to leave a hole just a bit smaller than the bulb, and sliding it down over the bulb and fitting in to the top of the tube. Light tubes are not the same thing these are a tube within a tube, and a vacuum pulled in between for an excellent insulation value.
I made the pipe but cant really see any major temperature differences on nipple end. at the moment its free standing scenes I have no clue where to get the glass tubes. I will be trying to use cans in its place to see if I get any results. I will be making a video soon after I accomplish anything worth watching. Thanks for any ideas or help in advance.
where can ya get those so you can make a solar oven with a few.. I know they are in all commercial solar water heaters.. but I only need two or three for an oven.
how effective are solar vacuum tubes in cloudy weather i.e. in defused sunlight
ss7406 4 months ago
@ss7406 They are more effective than flat plate collectors in cloudy weather, but bear in mind there is not a lot of heat to collect in diffused light.
sundug69 4 months ago
what liquid inside the copper... of course, it is not solid copper
vnyeu 8 months ago
@vnyeu acetone
sundug69 8 months ago
there was a article in the late seventies that used the evacated tubes with a slight charge of co2 gas to increase the temp of the inside tube. the whole system was a compressorless air cond system. and a few years later the pyrex tubes were mirrored in the 180 back side to increase the heat even more. i built a system but used it to heat water and was impressed that the water would get to 210 degrees in a solar day. panel was 2.5 x 4ft, and heated a 30 gal barrel.
advthinker 9 months ago
These are great devices, I ran some tests on one years ago and the results were nothing short of fantastic
1BustedMyth 11 months ago
hi its been 2 years how have the tubes worked out for you
richallenmusic 11 months ago
@richallenmusic Unfortunately, these tubes have yet to be put into service- they are waiting for my procrastinating friends to install a HX water heater, so I can install the panels. However, I have made some extra heat pipes that I use for demonstrations, and they are still working fine.
sundug69 11 months ago
Thanks. Is there a ratio for the pipe volume to the fluid amount needed . If the pressure is rising in the tube does it self adjust the temperature at which the phase change takes place so their is always both liguid and gas. Could it all become gas at extreame pressure?
bscfrnd1 11 months ago
@bscfrnd1 I only know to use about 8cc for the 46" x 3/8" pipe I used, maybe you could figure from there. Yes, it could all become a gas at higher temps, that's why it's important to not use too much acetone, and normally the manifold will be removing the heat, avoiding pressure buildup.
sundug69 11 months ago
Thanks
bscfrnd1 11 months ago
I thought the glass tube was suppost to be evacuated and the solar fluid was in the copper pipe. Im confused :/
bscfrnd1 11 months ago
@bscfrnd1 The glass tubes are called evacuated tubes because they have a vacuum pulled in between the inner and outer tubes when they are manufactured. IOW, most of the air is evacuated from the small space between the two tubes when they are formed. They may or may not be then used with heat pipes, which are the metal pipe installed into the evacuated tubes to move the heat captured by the tubes out and into a manifold.
sundug69 11 months ago
can someone please explain how heat pipes work?
ebutuou123 1 year ago
@ebutuou123 A heat pipe is a closed tube with a small amount of working fluid inside. When sufficiently heated, the fluid boils, and rises to the cooler top of the tube where it condenses and gives up the heat it took to boil it. This is called a change of state, and is an efficient way to move heat. There is more detail to it, but that's a general overview.
sundug69 1 year ago
@ebutuou123 Google it, but its like a vacuum greenhouse that heats a copper pipe, highly efficient and very dangerous in hot climates, handle with care and install a professional geyser, u can save 1000's
catatonicable 4 months ago
hi,my final year project is about heat pipes in solar thermal system..you know where we can buy one of this pipes just for experimental reasons! thanks u!
ktmandra 1 year ago
@ktmandra No, but Google shopping might turn up one of these easily made heat pipes
sundug69 1 year ago
@ktmandra hi on ebay
richallenmusic 11 months ago
Did you make the evacuated tube or purchase it ?What are the copper scrub pads used for?
Bubblytubebob 1 year ago
@Bubblytubebob The evacuated tubes must be bought, the scrub pads help transfer heat from the inside of the tube to the heat pipe
sundug69 1 year ago
Sorry for being dumb but.... what do you do with the hot end that sticking out, and why does the copper tube not explode with the heat since you have sealed both ends?
lezbriddon 1 year ago
@lezbriddon The hot end goes into a manifold that liquid flows thru to transfer heat to the domestic water. If you put too much acetone into the heat pipe, it could create too much pressure, but instead of exploding, it would separate at a soldered joint, and take off like a rocket. I have experienced this.
sundug69 1 year ago
do you think this would work in a parabolic trough system.I am thinking about a large hot water system.
mrgreenbeans 1 year ago
Sure, as long as the heat pipe is angled so the liquid will run back down it. The problem with simple parabolas is they need to track, check out compound parabola solar collector at fossilfreedomDOT com
sundug69 1 year ago
Can you please tell me where you purchased the evacuated tubes and copper netting? What about using a glycol liquid instead of the netting? Thank you so much for sharing.
throwawaylist 1 year ago
Adding a lot of liquid like glycol to the collector would hurt performance, low mass collectors are best. Copper scrub pads are available lots of places, grocery stores, Wal Mart, hardware, etc. Search "evacuated tubes" for sources
sundug69 1 year ago
What is the heat transfer in watts by one of these tubes?
1foxtrot70 2 years ago
Can you please clarify what eactly is the nipple end of the tube, you call it a 6" riser? Is it hollow or solid? Also is there a vacuum only in the copper tube or are you pulling a vaccum in the glass tubes as well? Brilliant info thanks you so much for sharing!
enoxhs 2 years ago
It is a standard plumbing part, it's called a stubout, plumbers use it when roughing in new plumbing. It is a 6" (also comes in 12") piece of 1/2" copper tube, with one end sealed shut. The glass tubes have a vacuum in between them, you cannot make the evacuated tubes, only the heat pipe.
sundug69 2 years ago
I would like to build this and was wondering if you would show installing the baby bottle nipple and where could i get glass tubes if i cant reclaim old solar systems. do you think florescent light tubes would be strong enough to use.
dante042066 2 years ago
Installing the nipple just involves cutting the tip off to leave a hole just a bit smaller than the bulb, and sliding it down over the bulb and fitting in to the top of the tube. Light tubes are not the same thing these are a tube within a tube, and a vacuum pulled in between for an excellent insulation value.
sundug69 2 years ago
I made the pipe but cant really see any major temperature differences on nipple end. at the moment its free standing scenes I have no clue where to get the glass tubes. I will be trying to use cans in its place to see if I get any results. I will be making a video soon after I accomplish anything worth watching. Thanks for any ideas or help in advance.
extreme2locura 2 years ago
where can ya get those so you can make a solar oven with a few.. I know they are in all commercial solar water heaters.. but I only need two or three for an oven.
RMCrowley 2 years ago
My array has the top of the tubes up inside an enclosure, so no weather can get to into the tubes. I do not seal the tops, other than the nipples.
sundug69 3 years ago
Nice ~ Useing silicon for weather plug/seal ? To keep rain water out . Thanks for all Advice
SpikenAL 3 years ago
It`s 100% silicon, and can withstand those temps.
sundug69 3 years ago
How does the nipple not melt?
0pioid 3 years ago