#5. Geothermal probes. Thermal siphon.

Geothermal probes. Thermal siphon.

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• Greetings, my dears!
• As kids get older, the toys get more expensive
• Let`s have a real fun
• In today’s series
• We’ll look at
• the design of the geothermal probe
• And start to assemble it
• I’d like to reveal a part of the intrigue
• What is a geothermal probe?
• In this case it’s a thermal siphon
• Thermal siphon is a special case of a heat pipe
• How does it work?
• It’s a soldered pipe
• Let’s imagine that it’s a shut from both ends pipe
• If we somehow manage to pump the air out of it
• And fill it with, for example, water
• What will happen?
• First of all, water will accumulate at the bottom
• Saturated steam will rise to the top
• If we bring the heat to this point
• The water will start to boil
• At any temperature
• It can be 20 degrees
• Here it’s 10, here - 20
• The water is boiling and condenses
• Transfers heat
• And this point is heating up
• almost to the temperature of the lower point
• And backwards
• Water condenses here
• And under the influence of gravitational forces
• flows down the walls of the tube to the very bottom
• When it’s flowing on the walls
• if we apply heat here
• the water will evaporate here
• As it flows
• and condense here
• And the whole process will repeat again
• There’s some disadvantage
• of using water in the thermal siphon
• That it will work
• up to +5 degrees, maybe up to 0 degrees.
• If you need precise numbers, Google it
• So we won’t use water here
• But another gas
• As a variant we can use refrigerant here
• Any of the available
• There will be high pressure in the pipe
• Depending on the temperature
• one, two, three, maybe five atmospheres
• You can check out tables that show this info
• What’s nice about the variant
• when the thermosiphon is under high pressure
• Is that
• firstly, you can detect leakage
• by simple soaping
• But if it’s going to be under the low pressure
• when, for example, water
• can boil even at +50 degrees
• for it to boil at +50 degrees
• there should be 0.1 or 0.2 of atmospheric pressure
• In this case, if depressurization happens
• The air flows inside through the small hole
• And the thermal siphon stops working
• Here’s what, in short, a geothermal probe
• Now I’ll show you how
• I’ll be assembling it
• You already saw how I soldered the pipe
• This one
• It has 2 ends
• For refueling from this side
• a Schrader valve
• 1/2 inch thread from the other side
• On which we will put the connector
• half-inch to
• 16 mm
• of metal-plastic pipe
• I got reinforced connectors
• At first I was confused that
• This connector consists of 2 parts
• You can see that it has two parts
• I opened it from this side
• It’s all done good here
• Looks like they are soldered and then
• it’s treated with a cutter
• and polished
• You really can’t tell that there’s two parts
• Oh, here it is, I just saw it
• Here it’s assembled in one
• But you still can disconnect the parts
• It should be airtight
• We’ll see
• We’ll replace them if something happens
• So, I take the silicone
• Smear it all over the thread
• The sealant, to be more precise
• Silicone is a special case here
• Next, I take my favorite tow
• and wind it up here
• Using tow here is reliable
• for cases like this one
• All these FUM tapes
• and other crap
• works much worse
• Or I’ll need to learn how to use them
• Than silicon + tow
• At home, the entire heating system is mounted in this way
• So far, not even one leakage detected
• Now I’ll do all of them it this way and we’ll continue
• Started doing connections
• of the metal-plastic pipes
• What should be noted here
• in this construction
• among useful things
• that it assembles quite easy
• Whoop and it’s ready
• Then you need to only slightly adjust it
• bend it this way
• And it sits on it’s place
• Tighten it up
• Superb!
• In comparison with the usual connectors - night and day
• I’m not sure how much better it’ll be
• Will there be more problems or not
• We’ll see
• Also, it should be noted that
• All pipes must be at an angle
• slight angle
• They must be angled towards the ground
• If there will be a counter-angle
• the moisture will accumulate there
• Bending it
• At the end of the assembly
• I’ll make a video
• of how it’ll all look
• Ok, now it looks like that
• looks cool, right?
• It’s a view from the top
• I’ll need to make it more presentable
• But I want to touch a thermal syphon question again
• I had a problem - what to fill a thermal siphon with?
• As I mentioned earlier, it should be under the excess pressure
• In our case, the operating temperature range
• at which thermal siphons will work
• is going to be about
• -10 degrees, that’s a minimum
• We’ll say starting from -10 degrees
• up to +10 - +20 degrees
• What to fill it with?
• I was banging my head…
• If we fill it with
• At first I had an idea to fill it with propane-butane
• But then most of the work would’ve been done by propane
• A the butane would’ve been a simple ballast
• But a propane at +10 already has 4 atmospheres
• And it’s a quite high pressure
• The same goes for
• the freons of type R22 and others
• At first,
• And then I thought, maybe fill it with butane?
• But butane has slight disadvantage
• It starts to boil at the atmospheric pressure of -0.5 degrees
• Which means that if the temperature drops in our thermal siphons
• the pressure will be below atmospheric
• And I don’t like that
• Then the great MR. FREEZE - Roman Aleksandrovych
• You’ll meet him later
• Made a valuable suggestion
• Did you know that there’s a thing called “isobutane”?
• And this thing…
• So called R600A
• Which can be purchased in a clean form
• in the cylinders
• For a reasonable money
• About 200+ hryvnas ($10)
• So, I chose it right away
• I read a bit on that topic. Turns out that
• it starts to boil at -10 degrees
• which is ideal
• At +10 degrees it has 2 atmospheres
• of absolute pressure or one of redundant pressure
• Seem pretty great from my point of view…
• Not to mention that it’s harmless for the ozone layer
• According to my calculations
• the pipe needs to be filled with 25 grams of refrigerant
• Each pipe will have about 0.5 meters
• of liquid
• And we don’t really need more
• or less
• It’ll be hard to measure 25 grams
• We’ll have to put up a laboratory or kitchen scales
• which can measure these 25 grams
• I’ll show you how it’s done
• Before thermal syphons refueling
• I decided to check the temperature
• on the probes thermal sensors
• This will be a reference data
• for further observations
• 4 days have passed
• Almost 5 after refueling
• with the pressurized air
• This one let out almost all the air
• I decided that it was a faulty Schroeder’s valve.
• These ones - the pressure was a bit lower
• This guy and this one too
• When I pumped in compressed air
• I screwed the cap not very tight
• screwed it very lightly
• And apparently the air got through the valve
• Because I was doing crimping again
• soaped it again
• If there’s a leakage
• it should be at the end of the pipe
• I’ll fuel it now
• And then we’ll see
• If the pipes will stop working
• we’ll need to
• either pour something at the bottom
• to seal
• the holes
• It can be done
• there’s a spray for fixing broken tyres
• and this spray seals the tyre. We’ll see.
• We’ll fill in about 25 grams
• of Freon R600A
• And then we’ll start the assembly
• of the compressor
• If you noticed
• you now can see that it’s connected
• to the heating line
• Both of these pipes
• I made it before refueling R600A
• for the reason that
• it’s flammable
• and it’s heavier than the air
• It’ll accumulate here
• If in the future I will be doing some work here
• the pit needs to be pretty well ventilated
• before using open flame
• And only after ventilation I’ll be able to work here
• Or there will be a “BIG BANG BADA BOOM!!”
• The pit is small, nobody will hear the bang :)
• Alright, we’re doing the first stage of thermal siphons fueling
• we’re vacuuming the system
• The process is slow
• Especially, counting that I bought
• a cheap vacuum pump
• it’s productivity is 24 liters
• one of the weakest pumps
• I bought it
• real cheap
• to make my experiments less expensive
• And second - it has 2 speeds
• The vacuum degree should be higher.
• We’re not in a hurry
• All we need is a better vacuum degree
• And how much it’s gonna take - really does not matter
• It costs about $90
• Plus refueling collector for $30
• Moving on
• That’s how I adapted the scales
• Because the hose at the top affects readings
• A little life hack
• when refueling thermal siphons
• you fuel them to a certain degree of vacuum
• then close the valve
• And for a second
• open the freon
• just a tiny bit
• We let the freon into the system
• And because it’s heavier than air
• it should go down in the tube
• and the air should go up
• they’ll partially mix
• After that
• open up the compressor valve
• and pump out the mixture
• The compressor sound changes
• pump it out
• Then
• Close it and stop the vacuum pump
• flip the cylinder upside down
• I don’t know if I can take it off
• Cylinder in the hands. Turning off the compressor.
• Close here
• Letting out the gas
• The cylinder is in my hands, turned upside down
• Here’s it
• I hold it with my hands
• heating it up a bit
• The ground and air temperatures are almost the same
• About +8 degrees
• It’s fueled up
• So here’s it
• I’ll let it pump further
• Cut it out
• The cylinder is turned upside down
• I put the cylinder
• on the scales
• To roughly estimate the weight
• Around 550 gram
• Now it’s 526
• Of course it would’ve been nice
• to hang it somewhere
• It ran out quietly here
• If it doesn’t run out, I warm it up a bit with my finger
• and it starts to run out
• We’ll need to wait
• until the pipes are empty
• I’m trying to warm it up
• with my hands
• That’s it
• So, the cylinder is empty
• It’s reusable
• We’ll try to refuel it
• Not sure how it’ll go
• because when I was disconnecting it
• residual gas escaped through the valve
• Maybe the Schrader valve got frozen
• We’ll see
• Alright guys,
• In the next video we’ll look at
• the compressor
• How the cooling machine is made
• We’ll see how it all turns out when we connect it
• See yall!