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This 'Cold Tube' can beat the summer heat without relying on air conditioning:
"Air conditioners work by cooling down and dehumidifying the air around us—an expensive and not particularly environmentally friendly proposition," explains project co-lead Adam Rysanek, assistant professor of environmental systems at UBC's school of architecture and landscape architecture, whose work focuses on future energy systems and green buildings. "The Cold Tube works by absorbing the heat directly emitted by radiation from a person without having to cool the air passing over their skin. This achieves a significant amount of energy savings."
The Cold Tube is a system of rectangular wall or ceiling panels that are kept cold by chilled water circulating within them. Since heat naturally moves by radiation from a hotter surface to a colder surface, when a person stands beside or under the panel, their body heat radiates towards the colder panel. This creates a sensation of cooling like cold air flowing over the body even if the air temperature is quite high.
Although these types of cooling panels have been used in the building industry for several decades, what makes the Cold Tube unique is that it does not need to be combined with a dehumidification system. Just as a cold glass of lemonade would condense water on a hot summer day, cooling down walls and ceilings in buildings would also condense water without first drying out the air around the panels. The researchers behind the Cold Tube conceived of an airtight, humidity-repelling membrane to encase the chilled panels to prevent condensation from forming while still allowing radiation to travel through.
A new cooling system for your home?
(Score: 3, Insightful) by JoeMerchant on Thursday August 20 2020, @12:20PM (40 children)
Most places have groundwater at mean annual temperature - including day and night, so during the hot daytime the groundwater is quite a bit colder.
Around here, a 200' well gets easy access to water at ~64F, I might wish it to be colder for a chiller system, but when it's 90+F outside, 64 is pretty good.
If air-air heat exchangers weren't so damn cheap to install, rejecting heat from a refrigerant cycle into an "unlimited" supply of 64F water is very efficient.
Also, in the winter, 64F is quite warm compared to night time lows...
🌻🌻 [google.com]
(Score: 2) by ledow on Thursday August 20 2020, @01:42PM (2 children)
Most places, except most major population centres.
Oh, and we all just have to dig 200' wells under every property?
(Score: 4, Interesting) by RS3 on Thursday August 20 2020, @02:01PM
No, digging takes a long time, and when you hit bedrock, you'll wisely stop. Drilling is the way to go with wells.
And frankly it doesn't have to be every property. Municipal wells supply water for thousands of houses and businesses.
A place I used to work, which was the size of maybe 2 or 3 houses, had a building HVAC from probably the 1950s that used water, from the municipal supply, to cool the condenser. It had a thermally regulated valve that controlled the water flow depending on the amount of cooling needed, and the flow rate was reasonably low.
(Score: 2) by FatPhil on Friday August 21 2020, @08:13AM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 4, Interesting) by doke on Thursday August 20 2020, @02:11PM (23 children)
You would still need to pump the water around a loop that goes 200 ft down in the ground, and up into ceiling panels. The overhead part will be heavy, and occasionally spring leaks. You can probably get enough energy for the pumping from solar, but not on overcast days or at night.
Also, what does "The researchers behind the Cold Tube conceived of an airtight, humidity-repelling membrane to encase the chilled panels to prevent condensation from forming while still allowing radiation to travel through." mean? They "conceived" of it, but couldn't figure out how to make it? As dust accumulates, it's probably going to start condensing anyway. Then it will rain under the panels.
(Score: 3, Informative) by RS3 on Thursday August 20 2020, @03:51PM
Maybe 200 ft. I have a 400' well but the water is often about 33 feet down. And the water going back down helps balance the water going up, so the net pumping energy is much less than you think.
(Score: 1) by fustakrakich on Thursday August 20 2020, @04:50PM (21 children)
Um, you have to use circular logic, and realize the return line equalizes the pressure
La politica e i criminali sono la stessa cosa..
(Score: 2) by JoeMerchant on Thursday August 20 2020, @05:33PM (20 children)
It's basically a siphon pump for the long-haul. The pump energy is just to overcome wall friction in the pipes (which is negligible at low flow rates), and whatever energy is required to suck the water out of the aquifer substrate and push it back in at the other end. The scary big lift energy is balanced by scary big suction on the other side, as long as the "head" on the aquifer is reasonably close to the surface.
🌻🌻 [google.com]
(Score: 1) by fustakrakich on Thursday August 20 2020, @05:46PM (19 children)
Heh, I forgot, if the pipes are open at the bottom, gravity will be an issue. Drop in a submersible pump...
La politica e i criminali sono la stessa cosa..
(Score: 2) by JoeMerchant on Thursday August 20 2020, @07:04PM (18 children)
Yeah, beyond 33' of lift you need to push instead of suck.
Around here, the head on our 200' well is about 6' above ground level - flows into my tank without pump assist, but we still have a pump to get it to flow faster.
🌻🌻 [google.com]
(Score: 1) by fustakrakich on Thursday August 20 2020, @07:11PM (17 children)
If you have gravity flow, wouldn't a fatter pipe do the same thing without the pump?
La politica e i criminali sono la stessa cosa..
(Score: 2) by RS3 on Thursday August 20 2020, @07:21PM (5 children)
Yes but you want some actual pressure at your shower head, faucets, etc.- 20-60 PSI depending on preferences.
(Score: 1) by fustakrakich on Thursday August 20 2020, @08:16PM (4 children)
Yeah, I like 60. Shower massage works better, and it's almost like having one of those high pressure washers in your kitchen. And for the water cannon, well, goes without saying...
La politica e i criminali sono la stessa cosa..
(Score: 2) by RS3 on Thursday August 20 2020, @09:48PM (3 children)
Why stop at 60? Your local home improvement store can hook you up with 4,000. Dirt gonesky! Hang all your dishes in with you- get everything clean at once. :)
Now I'm going to have to try a pressure washer on some cookware...
(Score: 1) by fustakrakich on Thursday August 20 2020, @09:52PM
Most appliances and faucets, etc. are only built to handle up to 60.
At 4000, you don't want to even get nicked by the stream
La politica e i criminali sono la stessa cosa..
(Score: 3, Funny) by Bot on Saturday August 22 2020, @12:13AM (1 child)
Pressure washer and big pots, feasible in the open, where pieces of food ejected from the pots can land wherever.
With dishes, very very risky and of limited efficiency.
With glasses and smaller pieces not recommended at all.
Source: direct experience.
Account abandoned.
(Score: 2) by RS3 on Saturday August 22 2020, @01:06AM
Thank you for saving me from making a mess! That's pretty funny that you actually tried it. "Nothing ventured, nothing learned" or something like that...
(Score: 2) by JoeMerchant on Thursday August 20 2020, @07:29PM (10 children)
Yes, we could expand our 4" well to 12" (if we could get a permit to drill such a big hole into the aquifer), and then we could run that 12" pipe over to our holding tank, the water comes out of the ground with a high Hydrogen Sulfide content, letting it outgas before bringing it into the house is a good thing...
However, that's all "kinda weird" whereas the 4" borehole with submersible pump feeding a 2" line to the house system is bog-standard and competitively quoted by all the contractors. If you asked for the 12" borehole solution, not only would it cost a bit more because of the materials, bigger drill bit, etc. it would cost a LOT more just because it's weird and is using the kind of parts that generally only get used for huge (expensive) operations.
The spring pressure used to be quite a bit higher, high enough for showers on the 2nd floor in the 1950s if the stories are to be believed, but when the local municipal water supply tapped the aquifer and started pumping out of it, the pressure dropped a lot. They gave all the affected residents submersible pumps "for free" when they did that back in the 1960s, but from there we're on our own - had to replace the pump last year: $1200.
🌻🌻 [google.com]
(Score: 1) by fustakrakich on Thursday August 20 2020, @08:05PM (7 children)
:-) Just run two more 4" pipes... I kid I kid! I'm getting a clearer picture now...
For a giant bottling company, or actual local needs?
1200 bucks, damn thing should at least be gold plated. They last a long time?
La politica e i criminali sono la stessa cosa..
(Score: 2) by JoeMerchant on Thursday August 20 2020, @10:47PM (4 children)
The submersible pump itself is I think $450, the idiot neighbor I share the well with called a service contractor who charged him double what he could have paid if he had shopped the deal.
The one that died was put in by the local utility in the late 1960s, so, yeah, they last a while - or used to at least.
🌻🌻 [google.com]
(Score: 1) by fustakrakich on Thursday August 20 2020, @11:31PM (1 child)
The one that died was put in by the local utility in the late 1960s, so, yeah, they last a while - or used to at least.
Ah cool, then the kids will have something to do when they turn 50
La politica e i criminali sono la stessa cosa..
(Score: 3, Insightful) by JoeMerchant on Friday August 21 2020, @12:51AM
Ah cool, then the kids will have something to do when they turn 50
Well, the kids are already 15, so if this one lasts like the previous they'll be nearly 65 when it goes.
However, this one already "took a break" after a lightning strike - came back when the breakers were reset, but if it's like the yard lights - it might not be at 100% after that strike. Also, I'm pretty sure that industry endeavors to make things that DON'T last 50+ years anymore - in the name of saving $0.30 on bearings they can ensure that a pump will wear out after 10 or 20 years instead of 50 or 60.
🌻🌻 [google.com]
(Score: 2) by RS3 on Saturday August 22 2020, @01:10AM (1 child)
If you've got artesian you may not need a submersible- a normal self-priming centrifugal might be enough, or a jet pump for sure. Unless the level occasionally drops way down.
Interesting it's shared. I'd think the agreement would disallow one party making absolute decisions unless they're willing to pay 100%. That'd be my terms anyway.
(Score: 2) by JoeMerchant on Saturday August 22 2020, @02:49AM
The agreement is a handshake - property used to be single owner for the two houses, prior buyer lost the deal by trying to lawyer up the shared well agreement. Truth is, you can sink a whole new well, with pump, for about $3K - so there's little point in engaging lawyers over an agreement. Neighbor didn't demand payment, but the poor schmuck lost his $400K/yr job with Microsoft that he's been working at for 15+ years and is selling real-estate now, so I figured least I could do was chip in what I would have paid to have the whole thing done myself.
Most days we don't need to pump at all, when the submersible pump goes out it has typically taken us weeks to months to notice that it happened - never had the water table drop below about 6' of head around here. Same aquifer 200 miles south in Orange grove country, when a freeze is coming the groves crank up the 1000hp diesel pumps sucking on 12" boreholes to feed their "microdrip" irrigation systems, saturating the citrus trees before the freeze event, which apparently helps the fruit and tree survivability through the event. When the groves do that, our 6' of head drops to about -6 feet, we can still use a suction pump - have a hand powered pitcher pump on the wellhead for just those occasions, but even the 4hp gasoline pump won't fill the pond the way that the natural flow will when it's up.
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Thursday August 20 2020, @10:56PM (1 child)
Two... more...
How do you think pipes are measured, in order that flow from 3x 4"would give equal flow to 1x 12"?
Eeeeep.
(Score: 1) by fustakrakich on Thursday August 20 2020, @11:49PM
OMG! You're serious?!
Obviously you gotta bump up the pressure. Don't you know anything?
Man! I hope this didn't need a tag!
La politica e i criminali sono la stessa cosa..
(Score: 2) by RS3 on Thursday August 20 2020, @09:41PM (1 child)
Sorry you paid so much. I can't replace my 400' one, but I've pulled up a few 150-200' ones and changed a pump, replaced a bad check valve, fixed wire break, etc. It's normally 1" black polyethylene pipe. Some older ones would have used threaded steel and would need a derrick or something to pull them up. Ugh. To pull my 400' one they use a 3-wheeled motor-driven thing you could almost make out of 3 wheelbarrow wheels (and maybe I will someday...).
I've done some hydrogeology work and large municipal wells are typically 12-14", and the pumps run 480 3-phase and typically 1,000 gpm.
(Score: 2) by JoeMerchant on Saturday August 22 2020, @02:53AM
$600 once every 7+ years isn't a bad water bill... only other expense (besides electricity to the pressure pump) was a starter capacitor for the pressure pump - pump wouldn't start - struggled, so I pulled out the starter capacitor to get its specs for a replacement, then when I put the starter capacitor back in it fired right up. I ordered the replacement capacitor anyway, I think there's a Murphy corollary at work: keeping the replacement capacitor handy right by the pump means you'll never need it.
🌻🌻 [google.com]
(Score: 2) by RS3 on Thursday August 20 2020, @02:22PM (12 children)
Article doesn't mention it but the (air) fan in ACs uses quite a bit of energy, and air isn't a great heat container compared to water. You could incorporate an efficient compressor / refrigerant system into the water cooling panels if needed and overall would consume much less energy than air-based ACs. Yes, condensate and mold are problems but can be dealt with by cleaning and anti-mold coatings.
(Score: 2) by JoeMerchant on Thursday August 20 2020, @03:31PM (10 children)
I designed (but only partially built) an off-grid cabin with - potentially - a ground water chiller system of pipes in the ceiling of the sleeping area. My idea was to use copper pipe installed on a slope that would drain the condensate over to a gutter that would carry it outside, and yes, if you slam the door it might well rain inside.
We had a naturally flowing spring (4" borehole), and were already using it to feed a waterfall pond-filler, so the supply and discharge were taken care of, and would flow without any pump energy. The question remained: was it worth the effort and expense to install all that copper pipe as compared to slapping in a $200 window rattler that would chill the room faster and to a lower final temperature? For the money side of the equation, the window rattler wins hands down, even if you need a $1000 generator to drive it. Where that solution loses is in listening to a window rattler all night long - if you're going to the woods to sleep in a cabin, who wants to listen to the same A/C noises you hear at a Motel 6?
🌻🌻 [google.com]
(Score: 2) by RS3 on Thursday August 20 2020, @03:47PM (9 children)
Super-cool! Yes, pun intended, but great project. Yeah, that condensate is a difficult problem if you don't want indoor rain.
You're poisoned by capitalism- not all worthwhile projects are the least cost. You've learned, and are now sharing some of that. Imagine if everyone compiled what they learn!
But yes, copper has become quite expensive over the past 50 or so years.
I live in higher latitudes but still need (er, want) the window rattler occasionally but can't sleep with the noise, so I run it full-on for a couple of hours, get the bedroom down to 70 or so and I'm good for the night.
Thermodynamics is a favorite of mine- did very well with it in college. Didn't like partial differential equation analysis, but the bottom-line natural logarithm that it boils down to (another pun!) is pretty easy and makes sense to me.
Years ago I had seen in a Popular Science mag. where someone had 2 holes dug, insulated, and installed septic tanks, filled with large rocks, to act as hot and cold energy storage. Combined with solar panels, graywater heat reclamation, all integrated into an efficient control system with counter-flow heat exchangers is some of my dream system.
I'm really big on insulation. And, keeping the humidity OUT.
Does your cabin have good plastic moisture barrier under it? If not, can you add it? Maybe diminishing returns?
(Score: 2) by JoeMerchant on Thursday August 20 2020, @05:01PM
It's not only the money, it's also the time cost - which, ultimately, is why the cabin was never finished: not enough time to build it. Capitalism means you can just go to WallyWorld and buy a $200 AC unit and have it installed in less than an hour - as opposed to sourcing a truck full of copper pipe and sweating joints in the ceiling for 6 days before it's all assembled.
🌻🌻 [google.com]
(Score: 2) by JoeMerchant on Thursday August 20 2020, @05:09PM (7 children)
Hit send quick before joining a conference call, but it's a 99% listen conference, so....
Cabin is built on an elevated deck, interior floor is ~8' above outside ground - quite a bit more breeze up off the ground. I built the deck, almost built the stairs, then life happened. Sold the property a couple of years ago, not sure if I want to know if the buyers finished the cabin or not, they thought they were going to.
The big idea of the cold tubes was to get the radiant cooling while being able to leave the windows open for breeze at night, sort of like sleeping under a 64F cloudy sky, but one that doesn't rain or let the bugs in.
The floor, as I left it, was 6" deck boards with 1/4" to 1/2" gaps - never tested it myself but common wisdom is that mosquitoes and other noxious flying insects tend not to fly up through floor gaps like that. Easy enough to put in a solid finished floor, if needed. Just time and money.
🌻🌻 [google.com]
(Score: 2) by RS3 on Thursday August 20 2020, @07:26PM (6 children)
If I live 3x normal I still won't have enough time to do all the projects I envision. I need to win a big lottery and hire a team. Guess I have to play to win...
I envisioned you using soft copper tubing- no soldering.
Now they make those nice aluminum heat spreaders for under-floor PEX heating. Probably work great for cooling overhead, or in walls too. Nice sweat stains on the walls... Would need to finish walls with FRP and condensate troughs along the bottom. Some might object... More engineering needed...
(Score: 2) by JoeMerchant on Thursday August 20 2020, @09:22PM (5 children)
That would be a quicker install, but you're going to be looking at those pipes. Now, you made me think of putting a thin copper foil catchplate underneath, that could be practical, but would still dampen the radiant properties... When I thought about soft copper, in addition to appearance I also thought about irregularities in the "straight" sections leading to drip points...
I did learn about those heat exchangers later - when it had already become pretty obvious that the cabin wouldn't be happening. They'd work well, but I don't think you'd want to pay for enough of them to cover a ceiling.
I was going to go for Hawaiian style single-layer wall construction, maybe sprayed with ceramic insulation on the inside - the insulation could also semi waterproof the wall, but even Killz loses its anti-microbial action after a few years. There are some "nanotech" companies proposing shark-skin inspired antimicrobial surfaces, but I'm skeptical of their longevity: they use silver in their formulation, and I suspect that as the silver oxidizes the antimicrobial action dissipates.
🌻🌻 [google.com]
(Score: 2) by RS3 on Thursday August 20 2020, @09:45PM (4 children)
https://www.amazon.com/Ft-Aluminum-Transfer-Radiant-Heating/dp/B009KT7PO6 [amazon.com]
Pretty inexpensive. I was envisioning them behind something decorative. Again, maybe FRP?
(Score: 2) by JoeMerchant on Thursday August 20 2020, @10:55PM (3 children)
Nifty, and cheaper than the ones I was looking at... still, would work best for radiant heating/cooling if exposed. I think these are made to underlay concrete for hot water systems.
🌻🌻 [google.com]
(Score: 2) by RS3 on Friday August 21 2020, @02:27PM (2 children)
I've mostly seen them tacked up under wooden floors- between joists, up flat against subfloor. Again, these kinds of things are more common at higher latitudes like mine.
I'll have to think about this whole thing a lot more, but condensation seems like a huge problem for any chilled surface inside a structure. TFA talks about treated surfaces. I almost remember something about a coating that resists water, maybe ionically repels water? Not even sure if that's possible. Drip drip drip.
My personal preferred system, and they exist, would involve an air to liquid heat exchanger with fan and temp. control for each room. Water / anti-freeze would circulate to a central heating / cooling system, often located outside. That system can take or give heat to rooftop panels (which could radiate heat away at night), ground loop, air, graywater, underground thermal storage tanks, whatever.
The master heat pump doesn't need an efficiency-robbing refrigeration reverser- just a control system with solenoid valves to control what goes where. 2 master heat pumps might be needed, or would be more efficient- one for higher temps and one for lower temp ranges.
Control system is the fun part. :)
(Score: 2) by JoeMerchant on Friday August 21 2020, @04:13PM (1 child)
In a home you could probably control the mold better - my entire high school was air conditioned using a chilled water system, no opening windows anywhere, about 2 acres of flat roof. I had chronic bronchitis for 4 years, only cleared up in the summer months, and when I went to college it disappeared permanently.
🌻🌻 [google.com]
(Score: 2) by RS3 on Saturday August 22 2020, @01:18AM
Legionella...
(Score: 0) by Anonymous Coward on Thursday August 20 2020, @04:50PM
Even worse if they're the portable type that have everything inside the building with an exhaust vent to the outside. Rather than proper ones where the hot side of the machine is located outdoors with the energy being dissipated outside, rather than inside where it has to be cooled.