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Zero Emmisions Airconditioner idea

Jaune Pendragon

Jaune Pendragon

King Of Servants
Location
Avalon
Soooo I had an idea.

You know A/C's take suck up a lot of power right?

So i was thinking of a design that could work with zero emissions and take very little power to run and use no refrigerant. Unfortunately this idea would only be commercially applicable to be installed on top of a Sky scraper but once installed it could cool down the whole building with a fraction of the power that would normally be needed to do so.

So here's the idea.

You know how heatpipes work? And how ridiculously fast they are at transferring heat? First need a long heat pipe. This pipe needs to start from the ground floor in the center of the skyscraper all the way to the top and then above it. It should keep extending it until it reaches about near 2000 feet from sea level where the temperature reaches 11 degrees Celcius. Considering most skyscrapers higher than 300 m (984 ft) and "megatall" skyscrapers for those taller than 600 m (1,969 ft) the amount it should be fairly simple to set up. Of course there must this heat pipe must be insulated for the most part and it should have a good support to keep it from falling. The bottom where part of the heat pipes which are present in the building should have good heatexchangers with a few fans to blow hot air over them. these fans intun could be powered with solar panels or wind power.

Once this is completed the building would not have pay for cooling except if a fan or a heat exchanger is damaged. The heat pipes will last atleast 15 years before it needs maitainance or replacement.

installation costs might be a big big But the amount of money it would save in the long run for not having to pay for Electicity for A/C's nor maintanence for hundreds of A/C's in a sky scaper would be worth the investment.


What do you think?
 
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Is this actually feasible in real life? Cause if it is and it works you may need to patent the idea and protect it right now.
 
This is a fin fan chiller package with a ten million dollar standpipe attached to it for no productive reason.
 
Is a heat pipe actually able to move enough heat? This is pretty new to me however a skyscraper is a massive volume and a wick pump that relies on capillary forces ain't.
Do you have a cost estimate or estimate of how efficient this would be? Attempting to plug your numbers in broke this calculator. Heat Pipe Calculator | Copper Water Heat Pipes
Do you have a plan for dealing with wind forces?
Typical heatpipes seem to be less than 10feet long? Heat Pipes for Thermal Management | ACT How would you manufacture these?
 
Dark as Silver said:
Do you have a plan for dealing with wind forces?
Typical heatpipes seem to be less than 10feet long? Heat Pipes for Thermal Management | ACT How would you manufacture these?
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For dealing with the wind forces I'm thinking of it being reinforced with Titanium alloy around it to keep it safe, with steel support wire connected to four corners on top of the sky scraper to add more stability.

As for methods of Manufacture.....Well....I guess I have to check out how they manufacture it normally first and see it it is viable for this ridiculous idea.
 
Dark as Silver said:
Won't this impact its ability to evaporate and lose heat, if I remember right from my first googling they usually use copper or something which is 20 times more conductive than titanium.
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Not really. The Titanium will merely wrap around the Heat pipe which is wrapped in insulation until a few meters near the top, which is where the heat pipe is exposed to the Cold high altitude winds and the heat of the building is taken by the freezing temperatures above. Perhaps a Regid Heat sink could also be added to increase the efficiency at which heat is dissipated?
 
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Jaune Pendragon said:
Not really. The Titanium will merely wrap around the Heat pipe which is wrapped in insulation until a few meters near the top, which is where the heat pipe is exposed to the Cold high altitude winds and the heat of the building is taken by the freezing temperatures above. Perhaps a Regid Heat sink could also be added to increase the efficiency at which heat is dissipated?
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So, whats the heat flux you're expecting over the last couple of meters of this pipe? I haven't found a good estimate on how much heat needs to be air conditioned for a skyscraper yet on google
 
Dark as Silver said:
So, whats the heat flux you're expecting over the last couple of meters of this pipe? I haven't found a good estimate on how much heat needs to be air conditioned for a skyscraper yet on google
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Considering it reaches temperatures of 11degrees C at 2000ft and average skyscrapers are about a 1000 feet.....with the amount of heat that all the people and machine inside would be generating....

The Condenser and Evaporator need to be fairly large to be effective hmm... the Condenser should be about 9 meters wide and long? The evaporator on the other hand can be divided into multiple sections of the building.
 
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I still don't know how many watts of heat we need to get out of the average skyscraper and I'm still concerned about how much fluid transfer needs to happen to enable that through capillary action.
 
Jaune Pendragon said:
Considering how ridiculously fast Heat pipes can transfer heat. I don't think that's something you need to worry about.
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How fast you can transfer heat within a pipe is meaningless, if that heat cannot be dumped out of it at an equal rate. In order for there to be a cooling effect, your must fulfill

heat in =< heat out

as otherwise eventually the system will just fail in prolonged use.

So if you have for example 100kW of heating put in, you must expel those 100kW at the top of the heat pipe tower. 'A couple of feet' of uninsulated heat pipe... will not do that.

For something meant to cool down an entire skyscraper, we're talking of a very hefty air-cooled heat exchanger built 1000 feet.... above it. On one hand, winds are good for pushing air around into whatever fin-stacks end up there and improving heat transfer, on the other hand that's quite murderous wind-loads.

So think less of a single pipe, and more Eiffel tower, in terms of needed support construction.

More than that, while I'm not sure of the precise maths behind heat-pipes, I have to echo @Dark as Silver here: We're talking 2000ft long pipe powered by capillary action. This sounds like something that needs to be mathed out hard to say if this is possible even on paper.

EDIT:
for reference, this here:

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is the Scythe Fuma 2, a high-end air-cooled heatpipe-based CPU cooler. It uses 6 heatpipes in conjuction with a twin-tower double-fan design and a copper baseplate connected directly to the CPU.
It is total about 155mm/6.1 inches tall and weights about 1 kg / 2.2 pounds with the fans included.
Vast majority of that is the air-cooled fin-stack towers.

This hefty unit of a PC CPU air-cooler can keep a very small, very hot (so efficient heat transfer) surface producing a consistent 200W of heatload at a temperature of about 50-60 degrees C above ambient. So at room temperature of 21C, the cooled down surface temperature is at around 70-80 deg.C or 158-176 deg. F.

An adult human at rest gives off about 100 Watts. An old-school light-bulb is around 40-60 Watts. Most household appliances tend to be in the range of 100 - 1000 Watts.

So if the heatpipe is the only source of cooling, then this sort of heatpipe-to-finstack ratio is insufficient.
 
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Some approximations.

Let's assume an average person consumes 2500 kilocalories per day, and generally input = output over the long term so they will emit as much as heat. Let's assume half that amount is emitted inside the skyscraper (the rest at work and what not). Let's assume there's 3 people per residence unit, on average. Each kilocalorie is 0.001162 kwh, so 3 people * 2500 kcal/person * 0.001162 kwh * 1/2 = 4.35 kwh each day.

According to US Energy Information Administration survey data, households in larger, relatively modern apartment buildings in the northeast that use electric stoves for cooking use ~3700 kwh per year on average for non-space-heating, non-air-conditioning purposes; or approximately 10 kwh per day.

Code: 
select avg(kwh - kwhsph - kwhcol) from eia where typehuq = 5 and regionc = 1 and yearmaderange >= 5 and stovenfuel = 5;
kwh = total energy consumption
kwhsph = space heating energy consumption
kwhcol = air conditioning energy condition
eia = what I'm calling the SQL table
typehuq = housing unit type; 5 corresponds to "Apartment in a building with 5 or more units"
regionc = census region; 1 corresponds to the Northeast
yearmaderange = when the housing unit was built; >=5 corresponds to 1980 onward
stovenfuel = type of fuel used for stove; 5 corresponds to electricity

We are going to ignore things like conduction of building materials and energy gained from radiation sources (sunlight).

We'll round off the 14 kwh per day and say heat needs to be dissipated at a rate of approximately 0.5 kw per housing unit. By definition, that is 0.5 kJ/s. The heat of vaporisation for water is approximately 40kJ/mol, so, assuming perfect energy transfer between the two ends, to service the energy output by one residence unit you need the water to evaporate at a rate of 0.5 kJ/s * (1 mol/40 kJ) * (18 g/mol) = 0.225 g/s. If you have a 100-story building (reasonable for a 300m skyscraper) with 10 apartments per story, you'll need to evaporate 810 kg of water per hour. This is probably a fairly conservative estimate.

Something like that?
 
Altaigne said:
We are going to ignore things like conduction of building materials and energy gained from radiation sources (sunlight).
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I think most skyscrapers are office space or at least mixed and the majority of heat gain appears to from solar, I don't know these estimates are ideal. However I think the ball park is probably right.
I found this calculator, it limits the length to 50m which I think shows how abnormally large this plan is. Flow-rate and pressure-drop Simulator – John Cantor Heat Pumps
However there is a critical issue with this plan. Flow rate appears to be inversely proportional to length, probably because its being driven in part by the pressure gradient.
 
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