S1E8 – Nuclear Power Plants Essentials – Cooling Tower Transcript
This is a transcript of the video S1E8 – Nuclear Power Plants Essentials – Cooling Tower
G’day and welcome back to the Engineering All Sorts Video Courses – professional development for teachers, helping you to Engineer your Expertise. My name is Daniel, and I’m your navigator of all things Engineering. I’m also the founder of Engineering All Sorts, where we’re all about Engineering for Educators – stem education to help you to be confident in the details – over at engineeringallsorts.com.au.
In this video we’ll finally find out what those big concrete towers are used for in a nuclear power plant! This is where the water used to cool the steam down gives off the waste heat to the atmosphere. We will also consider the physics of cooling and the social effects of the cooling towers on the local area.
At the end of this video you’ll be able to:
- Identify the different components of a cooling tower in form and function
- Describe the flow and conversion of energy through a cooling tower
- Identify the key phenomenon that is exploited in a cooling tower to reduce the water temperature
- Contrast key considerations in the creation and operation of a nuclear power plant, such as physics and social effects
For the full list of learning outcomes, transcripts and worksheets for this series, check out the downloads section of the series at engineeringallsorts.com.au
We’re on the home stretch now, so let’s jump into the video – let’s take it apart!
The final major component of a nuclear power plant, and probably the most recognisable, is the cooling tower. We have the outline of one here with its large billowing vapour cloud coming out the top.
The cooling tower is used to remove the waste heat from the cooling water in circuit 3 so it can continue to be used in the condenser. The waste heat is transferred to the atmosphere using the cooling effect of evaporating water. In essence, it’s another heat exchanger, but this time it’s exchanging heat between water and air.
Warm water from the condenser is piped in and sprayed into the middle of the cooling tower. This falls onto a fill material, which is basically a porous filler to massively increase the surface area of the water. As we have seen before, the more surface area in a heat exchanger, the faster the heat transfer.
As some of the warm water evaporates into the air, the remaining water cools down and drips through the fill material into a collection dish at the bottom. This cool water then can be used again in the condenser.
As the ambient air warms up inside it starts to rise, and through the chimney effect, cooler air is sucked in the bottom, aiding the cooling even more. Sometimes fans are added to help this airflow even more.
One last thing that can be added is what is called a drift eliminator. These try to capture some of the vapour that is escaping out the top and send it back down so it can be reused. This increases the efficiency of the cooling tower, so it consumes less water.
As the air rises, the drift eliminator forces the rising air and vapour to change direction suddenly. The air can make the bend, but the vapour is heavier and can’t turn as quickly, so it’s knocked out of the air. It then collects on the drift eliminator and then falls back down to be reused. It’s not perfect, but it does help.
As we spoke of before, cooling towers are huge structures, and can often be seen from far away. They can be up to 200 meters tall! Some might consider these very unsightly buildings, so we have to consider their placement and the effect that they are going to have on the visual landscape. Many towers remain in place long after the rest of the power plant has been decommissioned and removed, simply because of the sheer cost and effort of knocking them down. As a result, we can’t just consider their effect during the life of the power plant, but also for many years afterwards.
But now, one last activity for this series. See if you can have a look for decommissioned or abandoned cooling towers around the world. What condition are they in? How long have they been there? Are there any future plans for them? Have they been repurposed already? What do the locals thinks of them?
Just pause the video to give yourself enough time, and then come back to us when you are done.
How did you go? Maybe the cooling towers are near where you live, or where you’ve visited. Feel free to share your research in the comments below, so we can all see what you’ve found.
In this video we’ve covered the basic concept of the cooling tower, which use evaporative cooling to transfer heat from the cooling water to the atmosphere. It again uses a heat exchanger, but it’s transferring heat between air and water this time. We looked at the drift eliminators which knock some of the extra water vapour out of the air. And we looked at the social effect of the cooling tower on the visual landscape.
Don’t forget you can check out the resources for this series and more professional development for teachers at engineeringallsorts.com.au, including learning outcomes, transcripts and worksheets.
If you haven’t left your comments below from the activity it would be great if you could also share that below, so we can all share our stem education.
Thanks for watching and I hope you’re looking forward to the next video, which is the last one for the series! You made it! I’ll see you there!
This is a transcript of the video S1E8 – Nuclear Power Plants Essentials – Cooling Tower