Gotta figure out how to make content, and at the same time he is a dad and wants to work on his home. So the best way to mix tech channel and working on your home is making up weird tech solutions for your home pc setups. Once upon a time they tried doing HTPC setups, and he was constantly installing new TVs and testing different couch gaming setups. I don’t think constantly changing the living room was very wife approved though.
24:10 The way "bladeless" fans work is that they have a small normal fan in the base which forces air through the front edge of the ring. This creates a low pressure area in front of the ring that draws air through the back creating a draft. Basically this makes the small fan move air like a larger fan. Hence their technical name: air multipliers. Needless to say filling the empty ring with a display would nullify this effect, making the air multiplier even less cost effective.
Also a lot of the higher end ones have selectable airflow. In certain scenarios its better to have the switches at the front and run patch panels/longer cables to the back. So if you dont have direct access to the rear of the rack due to Hot/Cold aisle seperation designs it makes it easier for technicians to hav it like that. However in scenarios where densitiy is key then having switches mounted at the rear with reverse airflow makes sense.
Interestingly I work at a place where a lot of networking from a few large retailers go at end of life, and nearly all the networking is cooled front to back, either permanently or configured that way and these aren't small companies. This includes the stuff coming from the data centers. At home I've mounted switches in the back despite this anyway since my home setup isn't dense enough for it to hurt anything.
@@PantherSerpahin yeah, I’m a Systems Engineer at a datacenter and you will typically have warm and cold isles - so the airflow matters. This obviously doesn’t matter for your home-lab since it’s basically the same air on both sides.
@@Karthex Yes alot of networking is configured front to back in Cooling because you would have a dedicted network rack so you want them to pull the air from the cold aisle. For your regular access switch or Top of the Rack Switch (usally found with larger installations and multiple server Racks) you would have them configured back to front cooling and mount them at the back to make managing and changing the cables easier. Smaller installations or Office Spaces Usally have the Network Configured Front to Back as which is the default of you dont specify while ordering.
In a datacenter the switches are either in a remote rack (less common these days) or face backwards. The last datacenter I designed we used 2 x 1U 48port 10g switches (for redundancy) and a 48p 10/100/1000 (the 10/100 ends up being important as not all networked PDU, ILOM, etc... ports talk 1g+.) We mounted these mid rack so it would cut down on the network cable lengths we needed to stock (nothing is ever more than 1/2 a rack away from it's switch ports)
Water is densest at 4 degrees, so if you leave water in the pool, that will be the minimum water temperature on the bottom of the pool at least until all the water in the pool freezes. So the pipes will have the 4 degree water on one side and earth, that is little warmer, on the other side. Basically you protect the water in the pipes freezing by leaving water in the pool. Depending on the depth of the pool, the water will almost surely not freeze to the bottom.
Letting a pool freeze damages the stucco (or whatever lining you use) quite a bit, and damages the pipes for the water returns. The only ways to winterize a pool without damage are winterizing chemicals + keeping the pool heated to like 50F, or draining the pool + use plugs for the drains and returns.
The instant hot water thing is actually code in Germany. It makes a ton of sense to keep all the water in the system up to temperature because keeping it warm needs less energy as bring it up all the way. But that's only good if all pipes are properly insulated.
No it doesn't. You're heating water and running a pump constantly, even if it's not being used. It's way less efficient than leaving the tap open for a minute until the water starts to come out hot. It's a luxury feature, most hotels have it. It's not ecological.
@@25566It's wasting water vs wasting energy. In North America it makes sense to waste the water while in Europe water is more expensive so you want to save the water
The reason the network switches have their ports on the "front" is because they are intended to be mounted facing the back of the rack. The ones at my company are almost all set up that way, and the fans run so they're pulling the cold air from the front of the rack, I.e. their back
i was going to comment on him asking that, typically speaking in the data centers i've been in (facebook, drop box, nvidia, tiktok etc.) generally have all servers and compute power in one room or even row meaning all networking can be run from the hot aisle up to the ladder rack, then over to seperate head racks for networking where all the cabling waterfalls down to the front. but also yes its not uncommon to mount network switches or aggregate layers in the "rear" of the cage in smaller commercial applications. although if its in your house, and cant see all the blinky cool lights for net act do you really get your cool guy "i have a 42u rack at home", points?
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Radiator behind the rack (like a rack-door) connected to the water system. Neither server and peripherals need to be directly connected to the water. Makes maintance much easier and you get all your heat away from the rack and possible room aswell. This is a common way to cool server rooms where you have hot/cold areas. But the radiator and fans usually sits beside two/more racks.
Rear Door Heat eXchanger (RDHX) is very common in the datacenter, Linus actually have experience with them when he toured that Canadian supercomputer a handful of years ago. Trying to get one for myself but no surprise they're really rare in the private market
@@MrMrRubic good luck man! i know you have probably checked marketplace already but its the way to go if you don’t mind used parts, i live in florida and crazy stuff from specialty companies pop up all the time including stuff coming out of nasa
I'm running something inspired by Linus's setup. Kind of a lightbulb moment to be honest when I was watching the video. Had all the electrical wiring upgraded when I bought my caravan. So it was a simple matter to make a small hole in the wall and run the cables through it to the other side. Totally isolates the heat and noise in another room from my living room, and all my peripherals still work.
Look at some cheap geothermal water to water heat pumps. Would need to add some reservoirs on either side but could then very cheaply “push” heat either direction
With well insulated pipes and a circulating always hot system its more efficient for mid sized and larger homes. You run the water lines in a way that the heat loss is going into heating the home anyway.
Linus is doing what we all think is cool and actually doing it instead of saying “nah too much work” like most say, keep on man! (Also huge props to saying where you have gotten stuff wrong which helps the small amount of others in the future, its super interesting)
I have a cistern 8’ deep, and it has 1.5 feet of soil cover. Out here in the prairie -40, where the frost line is up to 8 feet deep, unless the water gets down to the 2’ deep mark (wells are not an option here) the water never freezes. Cisterns I’ve installed for other acerage folk where I’ve insulated over the tank never have frost problem. I suspect keeping the thermal mass of a pool well above freezing shouldn’t be a problem. Aboveground pool pump rooms may be a different story, What is considered the depth to which you get frost in the ground in the lower mainland.
I did construction for a summer as a laborer when I was in college, and saw a geothermal tap drilled at a house to heat the house and the bathroom floors
Use the diy a/c chiller to increase the temperature delta. Instead of just one reservoir, use a cooler on each coil as a reservoir. The condenser reservoir (hot side) gets pumped to the pool loop, and the evaporator side (cold side) goes to the water cooler systems and a radiator for the room air
Linus, add an "Airtap A7 water heater" head to the room. Plumb it into the loop going to the pool after the server rack heat exchanger. The Airtap is like a window air-conditioner that pumps room heat into a tank, but in your case the tank is your pool.
Where im from we have district /central heating, some data centers put the heat they make in that system, meaning they sell the heat they make to the heating company.
15:00 thank you!!! someone else said it, you are paying for htat heat when its winter my NAS and utility closet gets opened its a good 4 or 5 degrees warmer in my house and during the summer my little 2x3 window gets popped open.
I helped a friend duct his (mining) server rack into his HVAC system. Then hooked it up to his thermostat as a dual stage furnace. If no heat was called for the hot air was dumped outside, if it called for heat the server heat was pushed through the HVAC system, and if the server was not generating enough heat then it also turned on the furnace.
The heat exchanger has two benefits: 1) You isolate a large part of the loop (the pool side) if you have a leak on the pc side 2) You can add glycol to the pool side to prevent it from freezing and use it throughout the winter, even if you empty the pool. Preventing condensation in the rack is relatively simple with a 3 port valve and ras pi (or dedicated specialist controller if you want to be fancy) to control it to a setpoint.
Switches are mostly mounted on the back side of the rack, this is why they often come with reverse airflow (back to front). You need to check the flow direction of switches before mounting them. This is because they usually are less than half the length of a server, if you would front mount them with ports on the back you would have to reach halfway through the rack to reach the ports.
regarding the switches and the ports on servers, you either mount the switches also in the back OR you have a patch panel back there, to patch it to the switch-rack OR you have cables going directly from the server to the switch-rack
I literally just installed an instant hot water circulation pump at my friend's place the other day, in the wintertime there is no waste from it as any heat radiated from it goes into the the house that your heating already. In the summertime you can have it turned off or run it off a thermostat or timer. I designed my water system with one trunk and short branches, my circulation pump pulls from the last branch so everywhere get pretty fast hot water, and I turn mine off in the summertime. As I switch to electric hot water and turn off the boiler in the summer, but I just installed high efficiency boiler so that might change
Dyson bladeless fans work by pushing high speed air out of the side of a ring so that the air inside the ring of faster air is dragged with it to increase the flow rate. So you get to use a high pressure air pump in the stand instead of a large swept area wing to propel air at you, and the blades don't get to push air outwards, it's all pushed in the direction you want. The viscosity of air both brings the blown air's speed down to an acceptable, non-turbulent, level while also moving a greater mass of air than went through the fan.
I think I almost understand that explanation 😅 (probably need an animation to truly grasp it, lol) But anyways, does that mean I should try one of those out, next summer? :)
I'm in quebec and the winters are also getting pretty hot. I have air conditioning, only it's a heater. If I want cool air in summer, I go downstairs. I move my setup twice a year just because downstairs/upstairs switch which is warmer
I’d like to see some people from Labs engineer you a solution to use the in floor heating loops and constant water heating loops and pool heating loops that would automatically switch on and off using the computer heat at different places, and using other gas powered heating. I could especially see it being useful if they actually measured all the water temperatures, such as what is being outputted by the computers and what is coming though all the different loops
The best thing for the new heat would be the inclusion of a radiator and fan just to help pull the heat out. Otherwise the only other option is to install a dedicated split air conditioning/heat pump unit.
Linus, for worying about condensation from low return temperature in winter, you can add a 4-way valve and choose the mixing ratio. This used to be a good practice before condensation in furnaces started bing a good thing.
Re: 4:00 In data centers you orient the devices based on airflow. So you end up having to purposefully mount them on the back or front but find them having their ports on different sides.
I think a hybrid water heater (Electric water heater with heat pump to stop standby losses) may be ideal for sucking up low-grade heat. Kind of ideal in the laundry room with a dryer for example. Edit: 25:20 Such water heaters are NOT compatible with a re-circulation pump (normally used in large buildings like hotels and apartments). I think it may be because they rely on keeping the water stratified in layers (with the hot water at the top, ready to use).
Linus, have you considered using the excess heat from your servers to pre-heat the cold water going into your hot water tank? If I recall correctly, in as previous video you showed the existing hot water tank already inside the server room.
Adding a heat exchanger in-line to the fill line would boost the incoming tap cold water a few degrees and when hot water is called for, it would be lukewarm going into the tank instead
But with the solar collectors on the roof feeding into the same tank, would you end up heating the loop to the server more then your dumping heat to the tank? Or would you need a second storage tank, so your heating the water 3 times?@@EricAnderson10
or even better, when the heater pulls cold water make it pull out of the loop directly. so the loop gets fresh cold water when the boiler pulls warm water from the loop. It will be more efficient than an exchanger. Issue of course is you are contaminating you boiled water.
When you order switches you specify your airflow to go from cold aisle to hot aisle. Is all your IO at the back? You order a back to front config and put the ports on the back. Really common.
If you installed a heat pump hot water tank, it would pull extra heat out of the server room into the hot water tank. Then you could use the hot water generated to supplement your in floor heating through the use of a plate heat exchanger
You can get some plumbing done and a small pump installed to circulate hot water through your pipes so when you turn on the hot tap it's instantly hot.
Another way to avoid condensation in the server room with very cold water would be to dehumidify it. The water can’t condense on surfaces if it’s not in the air Edit: nvm I have no idea what I’m talking about and apparently static electricity is an issue
On your pool loop, you need a manifold on the hot side and the cold side. The manifold on the hot side would be Ted to all the hot sources individually to each PC and the solar system. Then the cold side manifold would go to each cold side of all the PCs and the solar system. Also, you need to insulate every piece of piping that you can get your hands on. Insulate the piping in the server room as well as outside as well as in the access cover. These piping are not insulated. You’re right, you will lose all of your heat to where you really don’t want to lose it to. You made an interesting point at the end of the video. If you did mining in place of your pool heater or other types of heating sources, there would be a return on investment for your pool heating. Not sure if that would add up correctly or not. I guess it’s time to build a mining farm
A valid point to the network equipment is that you can actually change the airflow and mount them from the back of the rack. This is how you should do it proper way.
lots of times the switches are front facing ports because you don't have your switches in the same rack as your servers. Patch panels at the top of the rack (say like 24) that aggregate back to a main network rack that has the other end of patch panels to terminate to your huge rack FULL of switches, usually two racks for load balancing/redundancy.
Most enterprise switches can be either. A ton of companies have switched to top of rack switching where the switch faces the back with inverted airflow, then connects to all the servers. Its backhaul goes to the other racks.
What I would suggest instead of a heat exchanger, if you really want to capture every degree, is to incorporate a filter into the loop when it returns to your house. With a strong pump, which you already have, the flow rate should not be significantly affected. You probably already have a freshwater supply filter system in your house (at least that's standard where I am from), so maintenance is very low and can be combined.
Hi, you cold use the Heated Air to Heat your Use-Water, its called "Domestic water heat pump" what you get is coll air aund hot Water. Better then use Gas for hot water (CO2)
which is why I have been so hesitant to replace my aging yet still very serviceable evga SC2 1080ti. not only because I can't really justify the cost to replace while my games still run 'fine', but because, damn, I used to run ALL evga setups, it pains me so
What you need is a thermal dynamics expert, these are questions right in their field. Linus needs a modular home, but not like the type where the modular part is on the outside, just where literally every panel and board and everything around and between them are easy to take out and replace. So basically a house that doubles as a giant lego set.
Datacenters have switches that have airflow from back to front and are located in the back side of the rack thier called top of rack switches, the reason most have them on the front is because their supposed to be used in patch cabinets which is from patchpanel to switch which is a front side to front side style
You could dump the water into your floors during the winter month's but that probably is to late (Since I imagine you will not have pool water in the winter.) Saving on energy could you dump the heat from your AC unit allowing to heat your pool with the house heat.
Oh it’d be awesome to heat a fish tank that was heated, in part, by your PC-obviously a big fish tank with a a PID looped additional heater to maintain constant temperature and an alarm if it gets too hot, but it’d be a cool small version of the concept.
The pool PC cooling doesn't make much sense in Canada where you're heating the pool, but having a driveway-sourced heat pump hot water system in Australia makes a lot of sense. I'm surprised nobody sells one yet.
As an energy engineer this excess heat re-usal is super cool. You need to get Alex doing energy balances of your house to understand the best use for the heat. It may be too little for some applications or too much for others...
In the winter I would think you would lose a little bit of heat to the ground, then dump a bunch of heat into the cold water, but on the return loop to the house it would probably pick some heat back up again.
you hang the switch on the back of the rack if its a server rack. you hang it on the front if its used as patch panel to client PC's etc so you have the switch and right below it all patched off the lines to the various places in the building...
Telco equipment has ports at the front, because telcos know what they are doing... and they only have cables. Servers are descended from desktops, so ports on the back... and servers also have disks which fail a lot, so you make those accessible at the front.
FWIW most enterprise network vendors sell lines designed for front or back specifically for this as well as fan flow front or rear as well depending on how the DC is cooled.
Hi Linus. You can possibly bring the fireplace radiator idea to life if you put it in the ventilation system after the heat recovery, it is about 80-90% effective, but surely something can be taken out by the heat there. Possibly you could have set it earlier, but if it is -20c on the outside, there is probably a big risk of condensation.
Why not create a chimney effect with the entire server rack? Cool air is pulled in the rack from the front, and hot air is pushed up and out the top of the rack through radiators being cooled by the pool water. Then all your heat-generating devices are being cooled without modifying them at all. You can tweak the speed of the water flow and the number of radiators throughout the year. If it ever gets beyond reasonable then you add a mini-split.
Summer thought - Waste heat to peltier chips for extra electrical or cooling potential. Funny how each energy saving step does inherently introduce unrecoverable energy due to all the conversion inefficiencies. Side note, would be fun to watch yall take another shot at peltiers for all the times they let you down - push those guys to the limits!
I am installing a heat exchanger in my PC and running a loop outside to a hydronic heater. We can compare results soon. woot. Larger/more heat exchangers should be able to decrease those temperature deltas. The one I have is basically the full size of the area under my water cooled graphics card. I think it is 3" by 8" and 30 plates thick.
Put a timer on the Insta hot water, or tie it into home assistant and have it on demand. Then the water that you preheat is minimal, and your water heater would have to heat that water anyway. I live in a desert; I would rather save the water. But with a timer, button, or automaton, you don't need to waste anything. As a kid I saw an episode of 'This Old House' where an instant hot water loop was installed with a shower that resembled a carwash. I thought it was super excessive! But when done right, have your hot water, and save $ too.
I think the water spinning around before you get hot water is recycled back into the water heater. if I remembered that "This Old House" episode correctly.
You are already running an in-floor radiant heat system right? so in the winter could you just plumb your cold return loop from the in-floor heat through your head exchanger for the rack before you feed that water back into the boiler to re-heat and send back through your flooring? That "cold water" should be somewhere in the 60F range id thing, should be enough to extract heat from your exchanger/rack? The installation would just take a couple shut off valves and tee to swap from the "pool" cooler to the "in floor house" cooler
All I can say about port placement on rack equipment, is that past a certain point, you have a 42U rack for network equipment and a 42U rack for servers with only a top of rack switch(or two) for the servers in the rack. But then it's also usually the point where your 42U racks are in some sort of datacenter, where you can access the racks front or back the same so port placement isn't as much as a problem anyway. U racks against a wall are always fking annoying to work with no matter how small scale it is, we don't have tentacles and telescopic eyes to see whats going on behind the equipment.
If I'm not gaming, I throw up Folding@home rather than turning on the heater unless it gets really cold. For the pool, you need to look up the local frost depth in winter.
I don't know the full extent of of what utilities you have in that server room but, if you had a heatpump water heater in that room it would absorb all that extra ambient air heat and consentrate it in the water tank, in fact the best place to locate this kind of water heater is in the warmest location, generally outside of the air conditioned envelope such as a garage. The pool itself was truely overkill but using a large thermal mass of water (or the ground) was the right idea, a heatpump water heater in that room would by its nature cool the space
"I'll never make back what I spent on the implementation. If it wasn't for content, it would make no sense." The summation of your initiate to cool several computers by way of heating an outdoor pool could equally be applied to the vast majority of 'green energy' projects.
Water naturally gathers at a bottom of a deep enough container at ~4 degrees Celsius, cause it's at its most dense at that temperature. The warmer and colder water than that is lighter and rises to the top, mixing together. So put very simply, until all of the water is at 4 degrees Celsius, it won't freeze through-and-through. The exception to this is the surface layer, where it's in direct contact with freezing air. In that case, based on the air temperature, a layer of ice will appear on top. The ice sheet is a better insulator than the water, so as it gets thicker, less and less heat is lost to the air, which exponentially slows down the freezing of the pool. That's how you can have a body of water liquid under a very thick sheet of ice for, well, not ever, but pretty damn close.
I love how Linus is what everyone here is as well - an absolute nerd that gets excited about things, just with a bit more money to actually try out those things
Joe Listibruk (spelling?) Has a great amount of input on hot water design! Less than 3 seconds for hot water is his golden rule, mostly using hot water tanks and not the instant heaters.
Not worth the electricity. The main point of cooling the room is to save on AC. Cooling the room with AC defeats the point, even if an air to water AC may be more efficient.
my room gest quite cold in the winter, I'm thinking of making a Kotatsu desk by adding blankets around my desk and putting my PC under it. it (hopefully) creates a nice warm space underneath it while I'm gaming for free!
When water gets colder it becomes more dense so the cold water will sink to the bottom, water is at it's most dense at 4°c. So at the bottom of the ocean it is 4°c When water freezes it explodes into giant ice crystals becoming less dense than the water surrounding it causing it to float I don't know if that helps anything but it's a fun fact
Heating the water would be more expensive in most areas of the world, with the exception of severe droughts. At any rate, if you have any plants or garden in need of watering, you can store the cold water in a cannister to use on those later. Just make sure to let it sit for a while to let the cholorines etc. evaporate. Also, some hot water distributions may be adding anti-corrosion substances, so it may not be ideal for plants. That's btw why you shouldn't drink hot tap water.
3:28 they actually dont. Most Top-Of-Rack switches have the fans reversed so air go in from the "back" and come out of the "front" so they can ve mounted at the rear without disrupring airflow.
For winter you are going to need to use a bypass loop. Where some of your cpu heater water bypasses the pool and goes right back into the pool cooled water. That will prevent the inside loop from getting too cold and createing condensation. I think you will need a radiator in the room. To do that. Unfortunately that means your room will never be able to achive like less than 80 degrees for a pretty darn cold pool. So that means you will probably need to use a small water to water heat pump. That would fix both problems in one go. It would prevent it from getting too cold and allow you to get a greater temperature difference. You'd then need the temp of that to either always be set something like 65 degrees or if you wanted more exstream Temps You'd need to use something that will calculate due point and dynamically set that temperature. All of these sorta have issues with due point. Or the temp differential being so low that a room radiator wouldn't do much durring the summer.
Connected to some sort of heatpump this type of thing could probably save some serious $$$. My kit has a delta of just 1-4 degrees centigrade. It keeps us warm during winter with serious sub-zero temperatures and supply warm water all year round. But I might have this the wrong way around...
In the winter my family winterizes the pool, we drain the pool until the filter cant take in water and we drain and turn off the filter and we put the winter cover over the pool and we add anti freeze in it. I live in Ohio so i can only imagine how cold it gets in Canada
Get a bigger heat exchanger and put insulation on the coolant lines and heat exchanger , it should be really close If you want to go really insane. Put a heat pump system in there. You could supercool the PCs... basically an ac but instead of condensor use one of those ac to fluid heat exchangers on both sides Sub ambient pc cooling babyyyyy yeahhhh
I'm centralizing my PC components underneath my terrarium which in turn will be heated by all the PC stuff running. Since the terrarium is a rather closed enclosure, I'd dump the heat into my room. Especially in winter, it'll be good. I'm also planning to move a 3D printer there. With careful air management and sensors, I could maintain a constant temperature in the cabinet beneath the terrarium, heat my terrarium all year round (needed, as it's a tropical terrarium) and I have less PC stuff EVERYWHERE. The problem, however, is that I need to custom design everything as I cannot fit a rack, even a small one, under the terrarium. With a new flat (or house lol) and potentially higher ceilings, it'll work.
Due to pressure at a depth of around one meter I think the pressure on water is already high enough for it to "stay" at four degrees Celsius. This is due to the water density being at its maximum at that temperature, any lower and it will expand before it changes phase into ice.
Linus graduated from always redoing and rebuilding desk/gaming setups to always redoing and rebuilding his home setup.
Just his home ^^
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Just dad things lol
Gotta figure out how to make content, and at the same time he is a dad and wants to work on his home. So the best way to mix tech channel and working on your home is making up weird tech solutions for your home pc setups.
Once upon a time they tried doing HTPC setups, and he was constantly installing new TVs and testing different couch gaming setups. I don’t think constantly changing the living room was very wife approved though.
As we all 😅
Appreciate the name-drop @ 16:38! The basement water cooling setup is still running great, 8 years later.
Would be cool to see an update video, interesting project
@@undefined879 what because he makes minecraft videos? more relevant than you
@@undefined879 still more relevant than you've ever been and will ever be. crazy how that works
@@undefined879 I think your life needs you. go back and create something.
Good lord, I watched your golden apple videos YEARS ago... now that I'm 27 seeing your name was a blast to the past. Glad you're still around
24:10
The way "bladeless" fans work is that they have a small normal fan in the base which forces air through the front edge of the ring. This creates a low pressure area in front of the ring that draws air through the back creating a draft. Basically this makes the small fan move air like a larger fan. Hence their technical name: air multipliers.
Needless to say filling the empty ring with a display would nullify this effect, making the air multiplier even less cost effective.
Matthias Wandel has a great video demonstrating this principle!
Rack Mount Switches typically have their airflow back to front because you mount them at the back, where your server's io is.
Also a lot of the higher end ones have selectable airflow.
In certain scenarios its better to have the switches at the front and run patch panels/longer cables to the back. So if you dont have direct access to the rear of the rack due to Hot/Cold aisle seperation designs it makes it easier for technicians to hav it like that.
However in scenarios where densitiy is key then having switches mounted at the rear with reverse airflow makes sense.
Interestingly I work at a place where a lot of networking from a few large retailers go at end of life, and nearly all the networking is cooled front to back, either permanently or configured that way and these aren't small companies. This includes the stuff coming from the data centers. At home I've mounted switches in the back despite this anyway since my home setup isn't dense enough for it to hurt anything.
@@PantherSerpahin yeah, I’m a Systems Engineer at a datacenter and you will typically have warm and cold isles - so the airflow matters. This obviously doesn’t matter for your home-lab since it’s basically the same air on both sides.
@@Karthex Yes alot of networking is configured front to back in Cooling because you would have a dedicted network rack so you want them to pull the air from the cold aisle. For your regular access switch or Top of the Rack Switch (usally found with larger installations and multiple server Racks) you would have them configured back to front cooling and mount them at the back to make managing and changing the cables easier. Smaller installations or Office Spaces Usally have the Network Configured Front to Back as which is the default of you dont specify while ordering.
was going to say as most cabling for a rack will drop in from the back from above for a server room rack
In a datacenter the switches are either in a remote rack (less common these days) or face backwards. The last datacenter I designed we used 2 x 1U 48port 10g switches (for redundancy) and a 48p 10/100/1000 (the 10/100 ends up being important as not all networked PDU, ILOM, etc... ports talk 1g+.) We mounted these mid rack so it would cut down on the network cable lengths we needed to stock (nothing is ever more than 1/2 a rack away from it's switch ports)
Water is densest at 4 degrees, so if you leave water in the pool, that will be the minimum water temperature on the bottom of the pool at least until all the water in the pool freezes. So the pipes will have the 4 degree water on one side and earth, that is little warmer, on the other side. Basically you protect the water in the pipes freezing by leaving water in the pool. Depending on the depth of the pool, the water will almost surely not freeze to the bottom.
and the top freezing creates insulation for the water.
Letting a pool freeze damages the stucco (or whatever lining you use) quite a bit, and damages the pipes for the water returns. The only ways to winterize a pool without damage are winterizing chemicals + keeping the pool heated to like 50F, or draining the pool + use plugs for the drains and returns.
The instant hot water thing is actually code in Germany. It makes a ton of sense to keep all the water in the system up to temperature because keeping it warm needs less energy as bring it up all the way. But that's only good if all pipes are properly insulated.
No it doesn't. You're heating water and running a pump constantly, even if it's not being used. It's way less efficient than leaving the tap open for a minute until the water starts to come out hot. It's a luxury feature, most hotels have it. It's not ecological.
@@25566It's wasting water vs wasting energy. In North America it makes sense to waste the water while in Europe water is more expensive so you want to save the water
The reason the network switches have their ports on the "front" is because they are intended to be mounted facing the back of the rack. The ones at my company are almost all set up that way, and the fans run so they're pulling the cold air from the front of the rack, I.e. their back
i was going to comment on him asking that, typically speaking in the data centers i've been in (facebook, drop box, nvidia, tiktok etc.) generally have all servers and compute power in one room or even row meaning all networking can be run from the hot aisle up to the ladder rack, then over to seperate head racks for networking where all the cabling waterfalls down to the front. but also yes its not uncommon to mount network switches or aggregate layers in the "rear" of the cage in smaller commercial applications. although if its in your house, and cant see all the blinky cool lights for net act do you really get your cool guy "i have a 42u rack at home", points?
Radiator behind the rack (like a rack-door) connected to the water system. Neither server and peripherals need to be directly connected to the water. Makes maintance much easier and you get all your heat away from the rack and possible room aswell. This is a common way to cool server rooms where you have hot/cold areas. But the radiator and fans usually sits beside two/more racks.
Rear Door Heat eXchanger (RDHX) is very common in the datacenter, Linus actually have experience with them when he toured that Canadian supercomputer a handful of years ago. Trying to get one for myself but no surprise they're really rare in the private market
@@MrMrRubic good luck man! i know you have probably checked marketplace already but its the way to go if you don’t mind used parts, i live in florida and crazy stuff from specialty companies pop up all the time including stuff coming out of nasa
@@MrMrRubic He did mention Radiator Door, so he probably know about them. But the question is, if he will make the rational way or the content way.
I'm running something inspired by Linus's setup. Kind of a lightbulb moment to be honest when I was watching the video. Had all the electrical wiring upgraded when I bought my caravan. So it was a simple matter to make a small hole in the wall and run the cables through it to the other side. Totally isolates the heat and noise in another room from my living room, and all my peripherals still work.
It'll look like the engine room of a WW1-era submarine at this rate.
I would LOVE that, haha. Awesome!
This whole project could be a PhD thesis for a thermal engineering doctorate.
Look at some cheap geothermal water to water heat pumps. Would need to add some reservoirs on either side but could then very cheaply “push” heat either direction
With well insulated pipes and a circulating always hot system its more efficient for mid sized and larger homes. You run the water lines in a way that the heat loss is going into heating the home anyway.
Linus is doing what we all think is cool and actually doing it instead of saying “nah too much work” like most say, keep on man! (Also huge props to saying where you have gotten stuff wrong which helps the small amount of others in the future, its super interesting)
I have a cistern 8’ deep, and it has 1.5 feet of soil cover. Out here in the prairie -40, where the frost line is up to 8 feet deep, unless the water gets down to the 2’ deep mark (wells are not an option here) the water never freezes. Cisterns I’ve installed for other acerage folk where I’ve insulated over the tank never have frost problem. I suspect keeping the thermal mass of a pool well above freezing shouldn’t be a problem.
Aboveground pool pump rooms may be a different story,
What is considered the depth to which you get frost in the ground in the lower mainland.
I did construction for a summer as a laborer when I was in college, and saw a geothermal tap drilled at a house to heat the house and the bathroom floors
the cold but clean water can be used again.
it is just moved around the system for a bit.
helps thin the sewer contents as well.
Use the diy a/c chiller to increase the temperature delta. Instead of just one reservoir, use a cooler on each coil as a reservoir. The condenser reservoir (hot side) gets pumped to the pool loop, and the evaporator side (cold side) goes to the water cooler systems and a radiator for the room air
Servers with IO on front are usually not on rails i.e. small depth,
and servers on rails have cable arms where cables are safely tucked
Linus, add an "Airtap A7 water heater" head to the room. Plumb it into the loop going to the pool after the server rack heat exchanger. The Airtap is like a window air-conditioner that pumps room heat into a tank, but in your case the tank is your pool.
Where im from we have district /central heating, some data centers put the heat they make in that system, meaning they sell the heat they make to the heating company.
15:00 thank you!!! someone else said it, you are paying for htat heat when its winter my NAS and utility closet gets opened its a good 4 or 5 degrees warmer in my house and during the summer my little 2x3 window gets popped open.
I helped a friend duct his (mining) server rack into his HVAC system. Then hooked it up to his thermostat as a dual stage furnace. If no heat was called for the hot air was dumped outside, if it called for heat the server heat was pushed through the HVAC system, and if the server was not generating enough heat then it also turned on the furnace.
The heat exchanger has two benefits: 1) You isolate a large part of the loop (the pool side) if you have a leak on the pc side 2) You can add glycol to the pool side to prevent it from freezing and use it throughout the winter, even if you empty the pool.
Preventing condensation in the rack is relatively simple with a 3 port valve and ras pi (or dedicated specialist controller if you want to be fancy) to control it to a setpoint.
Switches are mostly mounted on the back side of the rack, this is why they often come with reverse airflow (back to front).
You need to check the flow direction of switches before mounting them.
This is because they usually are less than half the length of a server, if you would front mount them with ports on the back you would have to reach halfway through the rack to reach the ports.
regarding the switches and the ports on servers, you either mount the switches also in the back OR you have a patch panel back there, to patch it to the switch-rack OR you have cables going directly from the server to the switch-rack
I literally just installed an instant hot water circulation pump at my friend's place the other day, in the wintertime there is no waste from it as any heat radiated from it goes into the the house that your heating already. In the summertime you can have it turned off or run it off a thermostat or timer.
I designed my water system with one trunk and short branches, my circulation pump pulls from the last branch so everywhere get pretty fast hot water, and I turn mine off in the summertime. As I switch to electric hot water and turn off the boiler in the summer, but I just installed high efficiency boiler so that might change
Dyson bladeless fans work by pushing high speed air out of the side of a ring so that the air inside the ring of faster air is dragged with it to increase the flow rate. So you get to use a high pressure air pump in the stand instead of a large swept area wing to propel air at you, and the blades don't get to push air outwards, it's all pushed in the direction you want. The viscosity of air both brings the blown air's speed down to an acceptable, non-turbulent, level while also moving a greater mass of air than went through the fan.
I think I almost understand that explanation 😅
(probably need an animation to truly grasp it, lol)
But anyways, does that mean I should try one of those out, next summer? :)
@@MrNicoJac They also have dyson mark up
I'm in quebec and the winters are also getting pretty hot. I have air conditioning, only it's a heater. If I want cool air in summer, I go downstairs. I move my setup twice a year just because downstairs/upstairs switch which is warmer
I’d like to see some people from Labs engineer you a solution to use the in floor heating loops and constant water heating loops and pool heating loops that would automatically switch on and off using the computer heat at different places, and using other gas powered heating. I could especially see it being useful if they actually measured all the water temperatures, such as what is being outputted by the computers and what is coming though all the different loops
The best thing for the new heat would be the inclusion of a radiator and fan just to help pull the heat out. Otherwise the only other option is to install a dedicated split air conditioning/heat pump unit.
Linus, for worying about condensation from low return temperature in winter, you can add a 4-way valve and choose the mixing ratio. This used to be a good practice before condensation in furnaces started bing a good thing.
Re: 4:00 In data centers you orient the devices based on airflow. So you end up having to purposefully mount them on the back or front but find them having their ports on different sides.
""mine or fold..." -> or offer CUDA cores for people doing massive amounts for video upscaling via Stable Diffusion... :)
I think a hybrid water heater (Electric water heater with heat pump to stop standby losses) may be ideal for sucking up low-grade heat. Kind of ideal in the laundry room with a dryer for example.
Edit: 25:20 Such water heaters are NOT compatible with a re-circulation pump (normally used in large buildings like hotels and apartments). I think it may be because they rely on keeping the water stratified in layers (with the hot water at the top, ready to use).
Maybe if you add more insulation to the pool cover, you might help even more against freezing.
Linus, have you considered using the excess heat from your servers to pre-heat the cold water going into your hot water tank?
If I recall correctly, in as previous video you showed the existing hot water tank already inside the server room.
Problem with hot water tanks is they build up a lot of crap you don't want that getting into the small fins of a watercooling block
Adding a heat exchanger in-line to the fill line would boost the incoming tap cold water a few degrees and when hot water is called for, it would be lukewarm going into the tank instead
But with the solar collectors on the roof feeding into the same tank, would you end up heating the loop to the server more then your dumping heat to the tank? Or would you need a second storage tank, so your heating the water 3 times?@@EricAnderson10
or even better, when the heater pulls cold water make it pull out of the loop directly. so the loop gets fresh cold water when the boiler pulls warm water from the loop. It will be more efficient than an exchanger. Issue of course is you are contaminating you boiled water.
@@legendaryone66 Hybrid water heaters have their own heat pump: and will use any low-grade heat source.
When you order switches you specify your airflow to go from cold aisle to hot aisle. Is all your IO at the back? You order a back to front config and put the ports on the back. Really common.
If you installed a heat pump hot water tank, it would pull extra heat out of the server room into the hot water tank. Then you could use the hot water generated to supplement your in floor heating through the use of a plate heat exchanger
You can get some plumbing done and a small pump installed to circulate hot water through your pipes so when you turn on the hot tap it's instantly hot.
Heat exchanger before your hot water heater to preheat your tap cold a small amount - not major, but just a boost since it's free heat
Another way to avoid condensation in the server room with very cold water would be to dehumidify it. The water can’t condense on surfaces if it’s not in the air
Edit: nvm I have no idea what I’m talking about and apparently static electricity is an issue
Wouldn't dry = static?
@@Zwamdurkel maybe, idk
Which is one more reason server rooms have AC.
Server rooms usually need a humidifier to reduce static buildup.
That will increase static buildup
Considering the cooling loop going to his pool, I wonder if Linus has the only outdoor pool in Canada that doesn't freeze over during the winter.
When the whole family is gaming it becomes a Jacuzzi! ♨ 🌊
@@NeoDemocedes - Kids, we need more heat!
Since it's Canada, I'm pretty sure it will still be... 'freeze-able'?
It'll just take a more-severe cold snap, lol
Vancouver doesn't really snow and freeze.
On your pool loop, you need a manifold on the hot side and the cold side. The manifold on the hot side would be Ted to all the hot sources individually to each PC and the solar system. Then the cold side manifold would go to each cold side of all the PCs and the solar system.
Also, you need to insulate every piece of piping that you can get your hands on. Insulate the piping in the server room as well as outside as well as in the access cover. These piping are not insulated. You’re right, you will lose all of your heat to where you really don’t want to lose it to.
You made an interesting point at the end of the video. If you did mining in place of your pool heater or other types of heating sources, there would be a return on investment for your pool heating. Not sure if that would add up correctly or not. I guess it’s time to build a mining farm
A valid point to the network equipment is that you can actually change the airflow and mount them from the back of the rack. This is how you should do it proper way.
lots of times the switches are front facing ports because you don't have your switches in the same rack as your servers. Patch panels at the top of the rack (say like 24) that aggregate back to a main network rack that has the other end of patch panels to terminate to your huge rack FULL of switches, usually two racks for load balancing/redundancy.
Most enterprise switches can be either. A ton of companies have switched to top of rack switching where the switch faces the back with inverted airflow, then connects to all the servers. Its backhaul goes to the other racks.
What I would suggest instead of a heat exchanger, if you really want to capture every degree, is to incorporate a filter into the loop when it returns to your house. With a strong pump, which you already have, the flow rate should not be significantly affected. You probably already have a freshwater supply filter system in your house (at least that's standard where I am from), so maintenance is very low and can be combined.
Hi, you cold use the Heated Air to Heat your Use-Water, its called "Domestic water heat pump" what you get is coll air aund hot Water. Better then use Gas for hot water (CO2)
The fireplace idea sounds like a great April Fools prank for the wife and funny content for TH-cam
CSF Video: Dennis broke into Linus's house and pumped hot air out of his fireplace. He destroyed the chimney in the process.
And the hardwood floor.@@tyrannicpuppy
EVGA will be sorely missed in the GPU space. I have been using them since the 200 series through to the 30 series.
which is why I have been so hesitant to replace my aging yet still very serviceable evga SC2 1080ti. not only because I can't really justify the cost to replace while my games still run 'fine', but because, damn, I used to run ALL evga setups, it pains me so
What you need is a thermal dynamics expert, these are questions right in their field. Linus needs a modular home, but not like the type where the modular part is on the outside, just where literally every panel and board and everything around and between them are easy to take out and replace. So basically a house that doubles as a giant lego set.
Datacenters have switches that have airflow from back to front and are located in the back side of the rack thier called top of rack switches, the reason most have them on the front is because their supposed to be used in patch cabinets which is from patchpanel to switch which is a front side to front side style
You could dump the water into your floors during the winter month's but that probably is to late (Since I imagine you will not have pool water in the winter.) Saving on energy could you dump the heat from your AC unit allowing to heat your pool with the house heat.
Oh it’d be awesome to heat a fish tank that was heated, in part, by your PC-obviously a big fish tank with a a PID looped additional heater to maintain constant temperature and an alarm if it gets too hot, but it’d be a cool small version of the concept.
The pool PC cooling doesn't make much sense in Canada where you're heating the pool, but having a driveway-sourced heat pump hot water system in Australia makes a lot of sense. I'm surprised nobody sells one yet.
As an energy engineer this excess heat re-usal is super cool. You need to get Alex doing energy balances of your house to understand the best use for the heat. It may be too little for some applications or too much for others...
In the winter I would think you would lose a little bit of heat to the ground, then dump a bunch of heat into the cold water, but on the return loop to the house it would probably pick some heat back up again.
you hang the switch on the back of the rack if its a server rack.
you hang it on the front if its used as patch panel to client PC's etc so you have the switch and right below it all patched off the lines to the various places in the building...
Telco equipment has ports at the front, because telcos know what they are doing... and they only have cables. Servers are descended from desktops, so ports on the back... and servers also have disks which fail a lot, so you make those accessible at the front.
FWIW most enterprise network vendors sell lines designed for front or back specifically for this as well as fan flow front or rear as well depending on how the DC is cooled.
You could hook up the pump for the hot water loop in your bathroom to your home automation to just turn on, when someone is in the bathroom
Hi Linus.
You can possibly bring the fireplace radiator idea to life if you put it in the ventilation system after the heat recovery,
it is about 80-90% effective, but surely something can be taken out by the heat there.
Possibly you could have set it earlier, but if it is -20c on the outside, there is probably a big risk of condensation.
Why not create a chimney effect with the entire server rack? Cool air is pulled in the rack from the front, and hot air is pushed up and out the top of the rack through radiators being cooled by the pool water. Then all your heat-generating devices are being cooled without modifying them at all. You can tweak the speed of the water flow and the number of radiators throughout the year. If it ever gets beyond reasonable then you add a mini-split.
Hello, there is a central air circulation system in the house, because if it is, you should install it with a warm air blowing radiator in the winter.
Summer thought - Waste heat to peltier chips for extra electrical or cooling potential. Funny how each energy saving step does inherently introduce unrecoverable energy due to all the conversion inefficiencies. Side note, would be fun to watch yall take another shot at peltiers for all the times they let you down - push those guys to the limits!
I am installing a heat exchanger in my PC and running a loop outside to a hydronic heater. We can compare results soon. woot. Larger/more heat exchangers should be able to decrease those temperature deltas. The one I have is basically the full size of the area under my water cooled graphics card. I think it is 3" by 8" and 30 plates thick.
Put a timer on the Insta hot water, or tie it into home assistant and have it on demand. Then the water that you preheat is minimal, and your water heater would have to heat that water anyway. I live in a desert; I would rather save the water. But with a timer, button, or automaton, you don't need to waste anything.
As a kid I saw an episode of 'This Old House' where an instant hot water loop was installed with a shower that resembled a carwash. I thought it was super excessive! But when done right, have your hot water, and save $ too.
15:50
I did a similar thing with copper cables. Costed me 50€ and my room is cold and quiet in the summer.
I think the water spinning around before you get hot water is recycled back into the water heater. if I remembered that "This Old House" episode correctly.
You are already running an in-floor radiant heat system right? so in the winter could you just plumb your cold return loop from the in-floor heat through your head exchanger for the rack before you feed that water back into the boiler to re-heat and send back through your flooring? That "cold water" should be somewhere in the 60F range id thing, should be enough to extract heat from your exchanger/rack? The installation would just take a couple shut off valves and tee to swap from the "pool" cooler to the "in floor house" cooler
I love it ! These kinds of projects are the best, as its your house. And you can what you want to do xD
You could run a split system air conditioner and feed the pool filter water through a heat exchanger with the refrigerant.
All I can say about port placement on rack equipment, is that past a certain point, you have a 42U rack for network equipment and a 42U rack for servers with only a top of rack switch(or two) for the servers in the rack. But then it's also usually the point where your 42U racks are in some sort of datacenter, where you can access the racks front or back the same so port placement isn't as much as a problem anyway.
U racks against a wall are always fking annoying to work with no matter how small scale it is, we don't have tentacles and telescopic eyes to see whats going on behind the equipment.
Linus! Top of rack is deployed to the rear with back to front cooling!
If I'm not gaming, I throw up Folding@home rather than turning on the heater unless it gets really cold. For the pool, you need to look up the local frost depth in winter.
Use a heat pump. Instead of doing a straight water heat exchanger, use a heat pump like a geothermal system pumping heat out and into the pool
You mount he switch in the back of the rack if you are adding your switch to your server rack. It's easy.
Those circulating pumps for instant hot water is basically standard for uns in germany. Cant believe youve never heard about those :O
I don't know the full extent of of what utilities you have in that server room but, if you had a heatpump water heater in that room it would absorb all that extra ambient air heat and consentrate it in the water tank, in fact the best place to locate this kind of water heater is in the warmest location, generally outside of the air conditioned envelope such as a garage.
The pool itself was truely overkill but using a large thermal mass of water (or the ground) was the right idea, a heatpump water heater in that room would by its nature cool the space
"I'll never make back what I spent on the implementation. If it wasn't for content, it would make no sense." The summation of your initiate to cool several computers by way of heating an outdoor pool could equally be applied to the vast majority of 'green energy' projects.
insulate all of your pex pipes to prevent the heat from dissipating prior to where you want it to dissipate.
Water naturally gathers at a bottom of a deep enough container at ~4 degrees Celsius, cause it's at its most dense at that temperature. The warmer and colder water than that is lighter and rises to the top, mixing together. So put very simply, until all of the water is at 4 degrees Celsius, it won't freeze through-and-through. The exception to this is the surface layer, where it's in direct contact with freezing air. In that case, based on the air temperature, a layer of ice will appear on top. The ice sheet is a better insulator than the water, so as it gets thicker, less and less heat is lost to the air, which exponentially slows down the freezing of the pool. That's how you can have a body of water liquid under a very thick sheet of ice for, well, not ever, but pretty damn close.
I love how Linus is what everyone here is as well - an absolute nerd that gets excited about things, just with a bit more money to actually try out those things
Joe Listibruk (spelling?) Has a great amount of input on hot water design! Less than 3 seconds for hot water is his golden rule, mostly using hot water tanks and not the instant heaters.
Have you considered using a heat pump water heater to scavenge the ambient heat from the room and put it into your hot water for the house?
This! We had this in Houston and while slow, it did heat the pool with minimal power needed.
Or pool. I think the energy removed from a small server room would freeze it.
Not worth the electricity. The main point of cooling the room is to save on AC. Cooling the room with AC defeats the point, even if an air to water AC may be more efficient.
Box fan laying on hockey picks for a gap. Radiators on top. Then a blow up fire fabric thing
my room gest quite cold in the winter, I'm thinking of making a Kotatsu desk by adding blankets around my desk and putting my PC under it. it (hopefully) creates a nice warm space underneath it while I'm gaming for free!
Linus,
You need a Mixing valve .. like its everytime used in a central heating system.
„30% cool water, mixed with 70% warm water“
When water gets colder it becomes more dense so the cold water will sink to the bottom, water is at it's most dense at 4°c. So at the bottom of the ocean it is 4°c
When water freezes it explodes into giant ice crystals becoming less dense than the water surrounding it causing it to float
I don't know if that helps anything but it's a fun fact
Heating the water would be more expensive in most areas of the world, with the exception of severe droughts. At any rate, if you have any plants or garden in need of watering, you can store the cold water in a cannister to use on those later. Just make sure to let it sit for a while to let the cholorines etc. evaporate. Also, some hot water distributions may be adding anti-corrosion substances, so it may not be ideal for plants. That's btw why you shouldn't drink hot tap water.
3:28 they actually dont. Most Top-Of-Rack switches have the fans reversed so air go in from the "back" and come out of the "front" so they can ve mounted at the rear without disrupring airflow.
For winter you are going to need to use a bypass loop. Where some of your cpu heater water bypasses the pool and goes right back into the pool cooled water. That will prevent the inside loop from getting too cold and createing condensation.
I think you will need a radiator in the room. To do that. Unfortunately that means your room will never be able to achive like less than 80 degrees for a pretty darn cold pool. So that means you will probably need to use a small water to water heat pump. That would fix both problems in one go. It would prevent it from getting too cold and allow you to get a greater temperature difference.
You'd then need the temp of that to either always be set something like 65 degrees or if you wanted more exstream Temps You'd need to use something that will calculate due point and dynamically set that temperature.
All of these sorta have issues with due point. Or the temp differential being so low that a room radiator wouldn't do much durring the summer.
Connected to some sort of heatpump this type of thing could probably save some serious $$$. My kit has a delta of just 1-4 degrees centigrade. It keeps us warm during winter with serious sub-zero temperatures and supply warm water all year round. But I might have this the wrong way around...
In the winter my family winterizes the pool, we drain the pool until the filter cant take in water and we drain and turn off the filter and we put the winter cover over the pool and we add anti freeze in it. I live in Ohio so i can only imagine how cold it gets in Canada
Linus is in Vancouver, so it definitely gets colder where you are.
Get a bigger heat exchanger and put insulation on the coolant lines and heat exchanger , it should be really close
If you want to go really insane. Put a heat pump system in there. You could supercool the PCs... basically an ac but instead of condensor use one of those ac to fluid heat exchangers on both sides
Sub ambient pc cooling babyyyyy yeahhhh
I'm centralizing my PC components underneath my terrarium which in turn will be heated by all the PC stuff running. Since the terrarium is a rather closed enclosure, I'd dump the heat into my room. Especially in winter, it'll be good. I'm also planning to move a 3D printer there. With careful air management and sensors, I could maintain a constant temperature in the cabinet beneath the terrarium, heat my terrarium all year round (needed, as it's a tropical terrarium) and I have less PC stuff EVERYWHERE. The problem, however, is that I need to custom design everything as I cannot fit a rack, even a small one, under the terrarium.
With a new flat (or house lol) and potentially higher ceilings, it'll work.
Due to pressure at a depth of around one meter I think the pressure on water is already high enough for it to "stay" at four degrees Celsius.
This is due to the water density being at its maximum at that temperature, any lower and it will expand before it changes phase into ice.
@24:00 it is called the Venturi Effect!
POU on demand heating is much more efficient than a repeating loop, though perhaps a bit harder to maintain.