This is just a geothermal unit with the evaporator built around the load and instead of air to air transfer through convection it is air to air transfer through radiation... nothing but smoke and mirrors. The problem with efficiency and A/C is the excess heat generated by the compression element of the Refrigeration Cycle. The closest thing to 100% efficiency is achieved through absorption chillers that utilize an internal chemical reaction based off of external heat to produce compression through a metered system... neat idea though. Heating systems that utilize the same process are different though - you can achieve greater than 100% efficiency with the use of flash gas bypass designs that will say for example produce 1.5 tons of heat in a 1 ton system.
“Cold Tube” cooling system uses half the energy of an air conditioner
31–40 of 137 posts
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#32Earlier quoted context omitted.
New buildings are rather efficient in US. The problem is old buildings that use 5X the energy for HVAC. I echo that AC is quite efficient. Far more efficient than traditional heating. There's a misconception that hot areas are less environmentally friendly due to AC. The opposite is true. Hot areas are only 25 freedom units hotter than humans prefer. Cold areas have months of 50+ temperature difference. The misconcep…
It is amazing how tight we can make buildings today. I had to learn a lot about HVAC on a remodeling job a few years ago. I had no idea that the drywall can be sealed so tight that when the HVAC system is running it can be next to impossible to open a door without a pressure release duct. Also saw how the HVAC system had vents to bring in air from outside with baffles controlled by the system. Can't remember exact pu…
The outdoor fresh air intakes are typically via ERVs (Energy recovery ventilation systems). These systems bring in fresh air, filter it, and typically run it through a heat exchanger to minimize energy losses as the fresh air comes and and the stale air goes out.
The purpose is to prevent buildup of harmful gasses and VOCs (everything from CO2 to CO to regular out-gassing of furnitures, etc) that can become dangerous if not cycled regularly.
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#33This sounds pretty neat, but their description of cold things sucking thermal radiation doesn't jive with my freshman-physics understanding of thermodynamics. AFAICT they've got cold water circulating in a moisture-repellent membrane, so they're able to absorb heat by chilling the water in the pipes instead of fussing with the humidity in the air like most AC does. So it sounds like trading inefficiency of standard A…
> but their description of cold things sucking thermal radiation doesn't jive with my freshman-physics understanding of thermodynamics.
Pseudoscience alarms started to sound in my head, until I read the comments.
If I understood this correctly - you will still radiate heat as normal. But, since the thermal radiation you emit will reach these things (assuming line of sight), you won't have much reflected back at you (or at nearby objects, which would heat them up). And so, you feel colder, even though the air is not being chilled.
That would make sense, similar to how we can make ice during the night even in a desert. You can radiate heat into space(as not all thermal radiation will be absorbed by the air)
https://tecped.com/process-of-freezing-ice-in-the-desert-acc...
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#34Earlier quoted context omitted.
[I was wrong]
Air conditioners are often more than 100% efficient- they move more heat energy than they consume. (Of course if you start with a fossil fuel, turn it into electricity, and then pipe that into an AC unit, the overall efficiency will be dropped by the efficiency of the power plant, but it's still somewhat made up for by the advantages of heat pumps)
This is false
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#35> The notoriously bad energy efficiency of air conditioners Air conditioners are actually pretty fantastically efficient for what they do. The problem with air conditioners is that there's no way to move a ton of heat without using a lot of energy. So, they do use a lot, but they make the most of it. What's truly bad are our buildings that have the minimal insulation and sealing possible, leaking all that cold air ri…
> What's truly bad are our buildings that have the minimal insulation and sealing possible, leaking all that cold air right back out into the environment.
In the case of the house I'm currently at, it is pretty good at retaining heat in "winter" (in quotes, because it's Bay Area winter). However, in the summer it will be quite warm late at night. So sometimes I want it the other way around, I want it to radiate excess heat away as fast as possible, but I can't control that. We should be able to deploy "heatsinks" at night.
That's for a house. Modern office buildings are built like greenhouses, even when they are otherwise insulated.
We can't really roll out solar panels fast enough. They would help offsetting the cooling energy costs by a lot. After all, it's during warm sunny days where the air-conditioning needs are the greatest. They also provide shade.
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#36> The notoriously bad energy efficiency of air conditioners Air conditioners are actually pretty fantastically efficient for what they do. The problem with air conditioners is that there's no way to move a ton of heat without using a lot of energy. So, they do use a lot, but they make the most of it. What's truly bad are our buildings that have the minimal insulation and sealing possible, leaking all that cold air ri…
Portable air conditioners are bad. All the hot components are in the room with you and it takes air from the room and blows it outside.
Technology Connections has a good video about this: https://youtu.be/_-mBeYC2KGc?t=355
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#37Not sure why they are researching the mechanism, these systems are commonly installed in Germany and known as "Kühldecke" (cooling ceiling). https://de.wikipedia.org/wiki/K%C3%BChldecke
This is a bit different. A cooled ceiling cools the air through convection, but this isn't supposed to. Instead, it basically just "removes" the warm walls you'd experience in any other setting.
A cooled ceiling would cool more effectively but possibly not as efficiently.
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#38Earlier quoted context omitted.
There are some "radiant cooling" installations out there. Most use either the ceiling or the floor, for the reasons you point out.
Yeah, my brother used to work in a building that was cooled like this with a 'chilled beam' system - https://en.wikipedia.org/wiki/Chilled_beam Apparently it works pretty well.
That uses a different mechanism. It cools the air and relies on convection. TFA specifically avoids cooling the air.
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#39The author doesn't really explain it well because his explanation breaks some physics laws, so it doesn't "suck" your body heat away.
Instead, it lowers the amount of heat radiating onto you from your environment by replacing hot walls with cold walls, which will lower the temperature of your skin.
It's efficient specifically because it doesn't cool by convection (like every other cooler). This allows the designers to insulate it so they only have to offset temperature gained by incoming heat radiation when keeping it cool. That also means it won't cool the air, just the objects near it.
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#40Earlier quoted context omitted.
New buildings are rather efficient in US. The problem is old buildings that use 5X the energy for HVAC. I echo that AC is quite efficient. Far more efficient than traditional heating. There's a misconception that hot areas are less environmentally friendly due to AC. The opposite is true. Hot areas are only 25 freedom units hotter than humans prefer. Cold areas have months of 50+ temperature difference. The misconcep…
It is amazing how tight we can make buildings today. I had to learn a lot about HVAC on a remodeling job a few years ago. I had no idea that the drywall can be sealed so tight that when the HVAC system is running it can be next to impossible to open a door without a pressure release duct. Also saw how the HVAC system had vents to bring in air from outside with baffles controlled by the system. Can't remember exact pu…
Full Fresh Air is typically called an "economizer" at least in California. The idea of those is to save energy.
But there is also typically fresh air requirements to bring in some percentage of fresh air.
And lastly the HRV/ERV mentioned in the other comment is typically more a residential thing from what I've seen but that's totally a thing I want in my next house.