How Natural Draft Cooling Towers Work (Stack Effect)
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- čas přidán 14. 07. 2024
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Learn how natural draft cooling towers work! This 3D animated video shows you exactly how a natural draft cooling tower works! You will learn all of a natural draft cooling tower's main parts, how it works and some of its design features.
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▶️How Natural Draft Cooling Towers Work
Natural draft cooling towers (‘natural convection cooling towers’) use the principle of convective flow to provide air circulation.
Natural draft towers are usually very tall in order to induce adequate air flow, they are also expensive to construct and are only used for applications where a large constant cooling requirement over many years is required; a thermal power plant is one such application. We will use a thermal power plant natural draft cooling tower to describe how this type of tower works.
Cool cooling water is pumped from the cooling tower basin to the power plant. The cool cooling water is heated by the process and its temperature increases. The warm cooling water is now pumped back to the cooling tower to be cooled.
The incoming warm water is distributed through spray nozzles inside the tower. The spray nozzles spray the warm water evenly over the entire fill. Water passes downwards through the fill whilst air passes upwards. As the water travels through the fill, some of it evaporates which causes the remaining water to be cooled; this is evaporative cooling. As air travels through the fill, its temperature increases, and it rises to the top of the cooling tower due to the stack effect (hot air is less dense than cool air and thus rises above it). The air exiting the top of the tower draws in more air at the base of the tower, creating a natural air flow from the base to the top of the tower; this is the stack effect and it is continuous providing cooling water is constantly circulated.
The purpose of the spray nozzles and fill is to increase the contact surface area between the water and air. A large contact surface area yields a much greater heat transfer capacity. All heat exchangers rely upon a large contact surface area between what is being cooled and the cooling medium.
Another important part of the cooling tower is the drift eliminator. The white plume exiting this cooling tower is not smoke, it is actually moisture, specifically it is the cooling water that has evaporated. Water losses associated with evaporation can be quite large; these water losses are referred to as drift. In order to reduce these losses, a drift eliminator is used.
Drift eliminators consist of parallel blades arranged on the air discharge side of the tower to remove entrained water droplets from the exiting air stream. The shape of the drift eliminator requires the entrained water droplets to change direction several times prior to being discharged out of the tower. Air has little problem changing direction and passing through the drift eliminator, but water droplets impinge upon the drift eliminator, condense, then drip back down onto the fill, then return to the cooling tower basin.
Why do cooling towers have such weird shapes?
You might be wondering why natural draft cooling towers have such a unique shape. Well, there are two reasons. The first reason is that the shape reduces the amount of construction material required when building such a large tower. The second reason that the paraboloid shape of the tower accelerates the air flow through the tower, which increases the tower’s cooling capacity.
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can we say that natural draft= vacuum???
Best explanation, love this channel
I am going to have one of these build behind my house to cool my pc
😂i also want
INVEST INVEST INVEST
You killed me
"Intel inside" huh?
PC... powder by nuclear energy...🤣🤣🤣
My friend’s young daughter thought those power plants were cloud factories and the finished product came out those towers.
well technically she's not completely wrong
@@MrChoklad She really is not wrong. Clouds are water condensation, exactly what comes out of those cooling towers.
3-year-old child: look! Cloud making machines.
QAnon adults: Look! Proof of deep state manufacturing fake climate change to curb our freedom.
@@maestrovso perfectly logical
Just like what 6yo me think
For 50 years I have wondered how these work - now I know - fascinating and informative video - thank you
Same here
50 years 😮😮
Roshan NAIK
Information was hard to come by
People nowadays tend to neglect this fact.
When I was a kid I thought radioactive smoke comes out of those cooling towers lol
Some adults still think that=P
Some places it does!
@@paullangford8179 that water is not meant to have any contact with the potentially contaminated water of the reactor, It uses heat exchangers so the reactor water and the tower water are not mixing.
@@A.Martin Unless your Britian circa 1950 and just decide to skip the research and build 2 open cycle air cooled reactors where air is just blown through the pile and staight out the chimney!
Simpsons?
Im 44 yrs old... And have litterally spent 30 yrs wondering about this. Thank you for scratching a 30 yr old itch!
I cannot stress enough just how much John's videos have opened up my understanding of engineering principles and processes I once thought I was too... 'Dumb' to understand. His ability to convey how mechanisms work through both 3D animations and calm, un-hurried narration is second to none. Normally I dismiss CZcams creator's suggestions to subscribe to their paid content but, because HIS approach to teaching is so genuine and intuitive I subscribed for three months. Just for purely educational purposes.
Sorry.... JON not John
A natural draft cooling tower is essentially a huge vertical venturi tube. The added bonus is that as the hot humid air from the tower's base rises to pass thru the tower's constriction (throat), its velocity increases and its pressure drops (Bernoulli). This drop in pressure causes more water to condense out of the air mass (adiabatic cooling), creating a separate stream of hot air. This hot air stream accelerates the rising air mass and keeps it rising even after it clears the throat.
Basically, a sort of ground level cumulusnimbus cloud maker.
Cool!
I would expect the drift eliminator to be placed in the lowest pressure location in order to maximise the production of adiabatic condensate. But that's not the case in this schematic. Lowest pressure should be just atop of the narrowest section, same as you would have your atomiser in a carburettor. However, here it appears to be below the narrowest section, which is a region of high relative pressure. But then again, maybe there's other things going on or other considerations that aren't obvious to a casual observer like myself.
Thank you very much sir, now i clearly understood. I was amazed after hearing bacterial growth in cooling tower, thanks for the information.
Bacteria will grow almost anywhere and in the most unlikely places. It was the discovery of bacteria growing in Coke-plant effluent discharge (seriously toxic) that lead to the use of treating toxic industrial waste with bacteria. The result was the ability to treat chemical waste to the point where the discharge was drinkable.
@@PhilJonesIII Right! They also use bacteria to treat arsenic loaded rain water coming from old mine tailings.
Evaporative cooling is also used in many industrial refrigeration applications. Workers are made aware of the dangers presented by handling this water.
Why didn't I find you earlier. Just brilliant. The best explanation of cooling towers so far
Wow, that's an excellent, thorough and understandable explanation. THANK YOU!
My master's professor didn't even explain how a cooling tower works inside and expects us to know how to design an HVAC system for a building using both CWS and DX air conditioning. We were all lost! This has been extremely helpful!!! I'm preparing for final exams now and this has brought so much clarity into everything I was trying to memorize, which now I UNDERSTAND. THANK YOU.
I'm a fast learner (I bore easily) but I really appreciate you taking the time to carefully explain everything. Most 10 minute CZcams explainer videos skip over important points (often because the creators themselves doesn't understand them) and you end up with more questions than answers.
Good observation. Share your opinion concerning quick and easy videos that don't make much sense if you watch them a few times.
This video is super helpful, I have no need to know this but it's really interesting
The most explanatory video I've ever seen.
I enjoy learning and your video is very educational. I get a clearer idea of what goes on in these towers now. They are so distinctive and intriguing looking structures, towers, and now I know more about them. So thankyou.
Wow! So beautifully explained. Thank you so much.
just a thing; you went into calc III theories and i totally understood what you were saying. mad props; i owe my understanding of the difference of and the relationship between hyperboloids and hyperbolic paraboloids to you and this video. and i thought i was gonna learn about convection... mad thanks and props brother
@@savree-3d gotchu
Thanks for making the video. Love the content. It is simple in principle but the complexities came towards the end - freezing, bacteria growth, and probably calcification. The pumps, and/or the infusion water of the entire system probably needs to be modulated to regulate the basin water temperature.
Thank you so much, now i clearly understood.
I remember Kearsley power station near Bolton getting demolished in mid 80s. We used to go down and get thousands of 20mm ceramic spheres and use them in our catapults. The glass industry around Bolton was booming
this is cool, you basically learn all those basic in high school, but the way they are used here in this big scale, its just amazing!
very good video. Id like to point out that the exit for the cooled water is wider and usually has grates to prevent plugging of the water circulation pumps
Good point. We modelled a cooling water system (CWS) inlet with grates for a nuclear power station, and it was indeed much larger. The model did not exist when we made this video otherwise we would have most likely included it.
You're a very competent teacher. Thank you for the video!
As a future electrical engineering student I got to tour a nuclear power pant in some time in the late 1980s that was going online. It was a very interesting tour. I did get to see the cooling towers up close.
Excellent explanation, thank you
Cooling towers fascinate me as a kid because of how oddly shaped they are. Now I finally understood how it works.
Great informative content and explained in great detail, I searched for so long, couldn't find anywhere.Thanks a lot.
Excellent video! Very easy to understand.
Thank you for bringing so much rain
Thank you very much to understand for better way.
Excellent video, extremely informative and detailed. Thoroughly enjoyed the video. Just one tidbit bit of information jumped out at me.. "Forced draft cooling towers are rarely, if ever used" They're actually quite popular in the Oil and Gas refinery processing plants ! Albeit they are usually a different design, but they are out there ! :)
Beautiful explanation!
Great work!
loved the explanation thank you
Really great explanation.. I am completely new to this and you explained it very well. Often it is super hard to explain something complex in a simple way. Thanks again! Well done! I will be looking for some more details about why the towers have the shape they have. I got from your video that it has to do with improving air circulation..??? But I would to understand better how the shape helps in this. I will try to check out some of your other videos. This was the first of your videos I watched. Again, well done and thanks a lot!!!
Very Clear and details introduction, would like to learn about how the evaporation-crystallization mechanical works!
Technical know-how including Health and Safety knowledge! Thanks a lot.....
I'm sure they'd mix a small amount of the incoming hot water with the cold water in the basin in winter. This will keep it around 5 degrees Celsius to stop it freezing and will cost them nothing.
Thats what I figure would happen too.
The cooling water never gets cold enough to freeze as long as the plant is running... The hotter water is continuously sent to the cooling tower.
Thank you for the video
thank you for the free education...👍🏻
Boom, the best one
Awesome video!
Great video! Will help for my 4th class power engineering exam :)
Best of luck!
Outstanding presentation ! Thank you !
Thank you for easy and precise information!
You are welcome!
For Winterization, why not just divert some of the hot intake water directly to the basin to keep it warm enough?
Was kind of expecting that to be shown as the obvious solution...
It's a bit odd because another solution would be to simply install baffles to restrict airflow when freezing is a concern. You can compensate for lower temperature cooling air by reducing flow rate.
Thank you very much
The best video that I've ever seen in my life.. Thank you so much..
Extremely helpful 👍
Excellent video. Please make more
This is awesome, thank you!
Please upload "Air conditioning System" .... your explanation is great 👍 ....new subscriber 😋
Thank you so much for this video! I have just one doubt that doesn't got clear, I didn't understand the reasons of the shape of the tower (larger on top and thinner in the middle). Thank you!
excellent ....love from INDIA🥰
Excellent video.
You deliver excellent content to your audience. It's very interesting material. All of your effort put into creating this video is much appreciated. I'm truly grateful for your help!
You are most welcome!
Please apload video on steam boiler like Cochran, locomotive, webcock and Wilcox boiler.
Video was very informative,kindly make a video on the following points:- Range, Approach,cycle of concentration, NDCT heat load calculations and chemical dosing for tube scaling and biological fouling.
very nicely explained video...
Thanks for informative videos. It is good to have two more points. 1st, re-fill water pipes to replace that evaporated volume. 2nd, how air is passed through as cross flow, cases for low air flow versus high air flow due to windy day and why narrow bell shape body is needed.
Awesome vedio.... It clears my many concepts... Please keep on adding such 3D type vedioes... I am gonna to watch all 😍😍
@@savree-3d already done
Fantastic video, congratulations!
Great content
Excellent video! Thank you.
Glad it was helpful!
Thanks for your sharing
I’m amazed how the are built especially when you think when the first were built
i have often wondered how much power could have been gotten from some of those just using natural convection and a turbine kinda like those old wooden minature candle powered art peices. possibly even using baffles like tesla valves and rampump effect.
Good man
Cooling Towers are one of the most surreal designs
Thanks
You could just bypass some of the hot water straight to the basin to warm it if it is getting too cold in winter.
Absolutely saved me when writing a lab report
Hey thanks; always wondered about these cooling towers and happy to say I learned something new today. I'll have a look at yr linked courses below. Take care :-)
Great, thank you very much!
So It's a giant swamp cooler, like the one on my trailer.
Go figure, LOL
That's exactly what I thought swamp cooler
Thank you for your excellent video.
Just a minor correction - the water molecules are not heavier than air, they are lighter. The reason water accumulates on the drift eliminator is that it mostly allows for deposition of already condensed water in the form of aerosol - tiny droplets. These droplets - not the individual molecules - are much heavier than the particles of gas. What happens is similar to sedimentation of a suspension in a centrifuge - in this case sedimentation of an aerosol.
The plastic fill is similar to what was used in the cooling towers at Thorpe Marsh near Doncaster. The fill at the cooling Towers at Drakelow power Station was asbestos.
I would love to get some technical information on the cooling system that was used at the cooling towers at Willington in Derbyshire. I think it could have been an old Marley Davenport cooling system at Willington given the age of the towers.
The draft has also another component forcing the air up than the heat alone: As the water have evaporated, there is way more water vapor in the "warm" air. And because water vapor is about half density than the air, the more humid air becomes less dense than the dryer air at the bottom.
And the "drift eliminator" is not supposed to catch water molecules (these are actually lighter than air when in a vapor form), but to catch water droplets that have not evaporated, so those would present the real water loss.
Our lage nuke plants, at my company, us a large gate for the pump suction basin, as opposed to a drain and pipe. That is because the suction demands for the pumps is quite large(~500kgpm). The pipes a several meters in size.
coool!
Great !
Very nice explanation. Thanks a lot!
You're welcome
very informative
Interesting
Very informative video
I think it should be mentioned that the drift eliminators only return the water in liquid form and not the evaporated gaseous water :) the evaporated water happily passes through as it is actually composed of smaller and lighter molecules than air.
Not quite. The change in direction results in what we call 'impingement'. The pressure at those points is higher and it does cause the water to condense. Not all of it, but certainly a good portion.
@@PhilJonesIII The dynamic pressure change is totally negligible in this case. The water would have to travel at much higher speeds. Drift eliminators are based on the fact that the more dense droplets tend to change their direction less than the steam, thus they gather and coalesce into the surfaces.
Also I want to add that steam does not necessarily condense when you increase the pressure. It can also superheat. This depends on the ratio of steam and liquid water in the container.
thank you very very much. your videos are brilliant. please create more free videos for your youtube students.😊🌾
Really helpful!!
I'm so glad!
which application you used to make this 3D great cooling tower ?
and did you mean by induced or forced cooling tower artificial cooling tower ?
and what is rectangular cooling tower ?
is this what you explained cross flow or co-counter flow or counter flow cooling tower ?
Could you please make video on smog tower
Please make videos in detail working of nuclear power plant
We walked day and night by the big cooling tower, they have the plant but we have the power.
Which designing software did you used for making this video.....really loved it✌
@@savree-3d --- SolidWorks is a great program to create these animations !!
Dope
It's an interesting topic, but the same information could've easily been covered in half the time.
Good grief, no kidding!!!!!
This video is part of a courses, that's why he's doing 7 minutes recap after 12:00
@@akhirulfajar The information density is low from the start.
Why do they not have something like a turbo style generator to utilize the exhaust draft?
why aren't the internals at the slim part of the tower? you would expect the velocity to be highest there right? so wouldn't that give a better cooling effect?
7:09 Did anyone else instantly do this after he said it and got chills down their spine as it actually worked?
What's the temperature of hot water and cold water that this tower takes in and gives out?
15:10 Water droplets, not molecules. In fact, water molecules (17 daltons) are much lighter than air molecules - N2 (28 Da) or O2 (30 Da).