Name: 冷卻塔為什麼是這個形狀？ (Why Are Cooling Towers Shaped Like That?)
Uploaded: 2025-07-07T14:58:00.000Z
Duration: 19 min 48 s

This is not smoke, and this isn't a smokestack, at least not the kind we normally think of.

這不是煙，也不是煙囪，至少不是我們通常認為的那種。

程度副詞

It serves a totally different purpose at a power plant than smokestacks, whose job is moving combustion products high into the air, allowing them to disperse away from populated spaces.

它在發電廠的作用與煙囪完全不同，煙囪的作用是將燃燒產物轉移到高空，使其遠離居民區。

Maybe you already knew that, or at least suspected it, after all, you saw the title of this video.

也許你已經知道了，或者至少有所懷疑，畢竟你看到了這段視頻的標題。

Plus, this kind of tower is commonly associated with nuclear plants that don't combust anything at all to create the heat that drives their generators.

此外，這種塔通常與核電站有關，因為核電站根本不燃燒任何東西來產生驅動發電機的熱量。

The largest class of power plants, called thermal power stations, use steam turbines, or turbines, depending on how you say it.

最大的一類發電廠被稱為火力發電廠，使用蒸汽輪機或渦輪機，這取決於你怎麼說。

But once that steam makes it through the turbine, it needs to be condensed back into liquid water.

但是，蒸汽一旦通過渦輪機，就需要重新凝結成液態水。

You spend all those resources heating the water up, and then you spend even more resources to cool it back down.

你花了那麼多資源把水加熱，然後又花了更多資源把它冷卻下來。

And a power plant isn't much good if all the electricity it generates gets used up just trying to cool that steam back down.

如果發電廠產生的所有電力都被用來冷卻蒸汽，那麼發電廠也就沒什麼用了。

So engineers have come up with some pretty creative ways to cool huge amounts of water, like millions of gallons or tens of thousands of cubic meters per hour, and do it relatively efficiently.

是以，工程師們想出了一些非常有創意的方法來冷卻大量的水，比如每小時冷卻數百萬加侖或數萬立方米的水，而且效率相對較高。

Not all cooling towers look like this, but there are some really clever reasons for that iconic shape we all recognize, and I'm going to build one in the garage to show you how they work.

並不是所有的冷卻塔都是這個樣子，但我們都認識到，這種標誌性的形狀有一些非常巧妙的原因，我將在車庫裡建造一個冷卻塔，向大家展示它們是如何工作的。

I'm Grady, and this is Practical Engineering.  Power plants could just vent steam into the atmosphere, but generally, they don't do that.

我是格雷迪，這裡是實用工程。  發電廠可以直接將蒸汽排入大氣，但一般不會這樣做。

For one, it wouldn't be good for the environment.

The heat, moisture, and noise would affect wildlife and weather.

熱量、溼氣和噪音會影響野生動物和天氣。

The feedwater for a boiler is often carefully treated to avoid corrosion and mineral buildup in the machinery.

鍋爐給水通常要經過仔細處理，以避免腐蝕和礦物質在機械中積聚。

It's expensive water, so it doesn't make sense to set it free.

And for three, it would waste a lot of energy.

而對於三人來說，這會浪費大量能源。

It's generally less expensive to cool the steam down just enough to condense it back into liquid water so it can be reused as feedwater.

一般來說，將蒸汽冷卻到足以將其冷凝成液態水的程度，這樣就可以作為給水重新使用，成本較低。

但即便如此，也是一個巨大的挑戰。

I talked a little bit about how power plants actually consume a lot of energy in a previous video.

在之前的視頻中，我曾談及發電廠實際上是如何消耗大量能源的。

It's a net positive, of course, but any energy you spend on all the industrial processes required to produce electricity at scale is energy not being sent out to the grid.

當然，這是一個淨正值，但你花費在大規模發電所需的所有工業流程上的任何能源，都是沒有被輸送到電網的能源。

是以，工程師們希望高效地完成這項工作。

One simple option is to use a cooler stream of water that already exists, like a river, lake, or sea.

一種簡單的方法是利用已有的冷水流，如河流、湖泊或海洋。

And in fact, there are a lot of power plants near me that do exactly that.

事實上，在我附近有很多發電廠正是這樣做的。

This plant draws water from the lake on the south side, sends it through condensers, and then releases it into a channel where it flows to the north side of the lake.

該發電廠從南側的湖中取水，經過冷凝器，然後將水排放到一條水渠中，流向北側的湖泊。

The slow circulation gives that water time to cool down before it reaches the plant again.

緩慢的循環讓水有時間冷卻，然後再流向植物。

But it's not feasible to have a lake or river for cooling water at every thermal power plant, and there are a lot of environmental impacts with the heat and intakes that require careful consideration.

但是，在每個火力發電廠都用湖泊或河流作為冷卻水是不可行的，而且熱量和取水口對環境的影響也很大，需要仔細考慮。

So instead, lots of power plants use cooling towers.

是以，很多發電廠都使用冷卻塔。

You might be familiar with the various machines humans have devised for cooling stuff down.

您可能對人類設計的各種冷卻設備並不陌生。

You might even be enjoying the comfort of such a device right this very minute.

您甚至可能此時此刻就在享受這種設備帶來的舒適感。

But like I mentioned, the simplest way to cool something is to simply let natural physical processes do the work.

但正如我提到的，最簡單的冷卻方法就是讓自然物理過程發揮作用。

After all, the temperature is usually less than boiling outside, so the heat from steam will naturally transfer to the ambient air if you let it.

畢竟，室外的溫度通常低於沸點，所以如果讓蒸汽的熱量自然而然地傳遞到周圍的空氣中。

這就是許多冷卻塔的工作原理。

I designed a cooling tower in my garage so I can show you exactly how this works.

我在自己的車庫裡設計了一個冷卻塔，可以向你們展示它是如何工作的。

This is made from laser-cut strips of acrylic with a carefully selected shape.

它由脈衝光切割的亞克力條製成，形狀經過精心挑選。

And when I carefully tape these carefully sized strips together, I get a nice, somewhat transparent cooling tower.

當我小心翼翼地把這些大小合適的條帶粘在一起時，我就得到了一個漂亮的、有點透明的冷卻塔。

This is a model of a natural draft tower.

It's not the most common type out there, but it is one of the simplest and also the most iconic and recognizable, so it's perfect for this demonstration.

它不是最常見的類型，但卻是最簡單的類型之一，也是最具標誌性和辨識度的類型，是以非常適合這次演示。

You may have noticed the holes I drilled in the bottom of each acrylic strip.

您可能已經注意到我在每條亞克力條的底部都鑽了孔。

This tower needs a way for air to get inside at the bottom.

這座塔的底部需要有一條讓空氣進入塔內的通道。

If you look closely at the real thing, you'll see something similar.

如果你仔細觀察實物，就會發現類似的情況。

They aren't continuous all the way down, but actually open around the bottom.

它們並不是一直向下延伸的，而是在底部開口。

Steam from turbines doesn't go to the cooling tower directly.

渦輪機產生的蒸汽不會直接進入冷卻塔。

Instead, there's a separate stream of water, aptly called the cooling water.

取而代之的是一股獨立的水流，恰如其分地稱為冷卻水。

The steam is condensed into liquid water in the condenser that's cooled by the cooling water, which then flows between the condenser and the tower.

蒸汽在冷凝器中冷凝成液態水，液態水被冷卻水冷卻，然後在冷凝器和塔之間流動。

I'm simulating that here with a bucket of hot water and a beer brewing pump.

我在這裡用一桶熱水和一個啤酒釀造泵進行模擬。

That hot water gets pumped to sprayers inside the tower.

If you know a little bit about thermodynamics, you know that we can only get this water as cool as the ambient air temperature.

如果你對熱力學稍有了解，你就會知道，我們只能讓水的溫度達到環境空氣的溫度。

Heat naturally flows from hot to cold, so you can't get any more heat transfer once the water reaches the outside temperature.

熱量會自然地從熱處流向冷處，是以一旦水達到室外溫度，就不會再有熱量傳遞。

But if you know a little bit more about thermodynamics, you know there's a trick that can improve the performance of a system like this.

但如果你對熱力學稍有了解，你就會知道有一個小竅門可以提高這樣一個系統的性能。

And this layer of material below the sprayers is the key.

而噴灑器下面的這層材料就是關鍵所在。

I'm just using a dehumidifier pad, but in an actual cooling tower, the fill is usually a layer of plastic carefully designed to maximize the surface area of the water in the system.

我只是在使用除溼墊，但在實際的冷卻塔中，填充物通常是一層精心設計的塑膠，以最大限度地增加系統中水的表面積。

It does this by forcing the water to either splash into tiny drops or form thin sheets as it falls downward.

它的作用是迫使水飛濺成小水滴，或在向下下落時形成薄片。

The goal is to expose as much surface area of the hot water as possible to the air flowing through the tower.

這樣做的目的是讓儘可能多的熱水表面積暴露在流經塔內的空氣中。

The pros call this counterflow, and it's the trick to the whole process.

專業人士稱之為逆流，這是整個過程的訣竅所在。

Actually, you can use crossflow as well, but let's jump over that rabbit hole for now.

實際上，您也可以使用交叉流，但我們還是先跳過這個兔子洞吧。

You might think the outside air has just one temperature, but to cooling professionals it has two.

您可能認為室外空氣只有一個溫度，但對於製冷專家來說，它有兩個溫度。

One we call the dry bulb temperature is what you normally encounter.

我們通常所說的乾球溫度就是您通常遇到的溫度。

That's what shows up in the weather report.

這就是天氣報告中顯示的內容。

If you soak the end of a thermometer and pass it through the air, that water will evaporate.

如果將溫度計的末端浸溼並穿過空氣，水分就會蒸發。

The drier the air, the more easily water evaporates.

空氣越乾燥，水分越容易蒸發。

This is why it feels so much hotter when it's also humid outside.

這就是為什麼室外潮溼時感覺更熱的原因。

It takes energy, called latent heat, to convert water from a liquid to a gas, and that energy is absorbed from the liquid water, cooling it down.

將水從液態轉化為氣態需要能量（稱為潛熱），這些能量會被液態水吸收，使其冷卻下來。

So as long as the ambient air isn't already saturated, 100% relative humidity, you can actually cool water below the dry bulb temperature using evaporation.

是以，只要環境空氣不是已經飽和（相對溼度為 100%），就可以利用蒸發將水冷卻到乾球溫度以下。

And the lower the humidity of the air, the more evaporation can take place, so the bigger the difference in wet and dry bulb temperatures.

空氣溼度越低，蒸發量就越大，乾溼球溫差也就越大。

Nature figured out evaporative cooling millions of years ago.

大自然早在幾百萬年前就發現了蒸發冷卻的原理。

這就是為什麼天熱時我們會出汗。

But using it at this scale is really impressive.

但在這種規模下使用它，確實令人印象深刻。

And it's not the only innovation in a natural draft cooling tower.

這並不是自然通風冷卻塔的唯一創新。

For that, I need to show you a cool graph.

為此，我需要向大家展示一張很酷的圖表。

You could spend an entire college course learning about this stuff, and there are probably a few HVAC professionals groaning at the screen right now.

你可以花整整一門大學課程來學習這些知識，而現在可能有一些暖通空調專業人士正在對著螢幕呻吟。

But I just want to use it to explain a few important things about the physical and thermal properties of air.

但我只想用它來解釋一些關於空氣物理和熱學特性的重要問題。

First, as the temperature of air goes up, its capacity to hold water goes up too.

首先，隨著空氣溫度的升高，它的持水能力也會隨之升高。

Kind of like hot tea can dissolve more sugar than cold tea, hot air can hold more water than cold air.

就像熱茶比冷茶能溶解更多的糖，熱空氣比冷空氣能容納更多的水。

Next, as air temperature goes up, its density goes down.

其次，隨著空氣溫度的升高，其密度也會降低。

Confusingly, the psychrometric chart actually shows specific volume, which is the inverse of air density.

令人困惑的是，心理測量圖實際上顯示的是比容，而比容是空氣密度的倒數。

So as you move up in temperature, these lines slope downward.

是以，隨著溫度的升高，這些線條會向下傾斜。

But maybe less intuitively, it's also true for humidity.

但也許不那麼直觀，溼度也是如此。

If you hold the temperature constant and just increase the amount of water in the air, its density goes down.

如果保持溫度不變，只是增加空氣中的水量，其密度就會下降。

Water molecules actually weigh less than the nitrogen or oxygen molecules in the air, so humid air is more buoyant than dry air.

實際上，水分子的重量小於空氣中的氮分子或氧分子，是以潮溼空氣的浮力大於乾燥空氣。

And this is the second key to a cooling tower, convection.

這就是冷卻塔的第二個關鍵--對流。

The hot water transfers its heat to the air.

The warm air becomes buoyant, flowing upward in the tower and drawing fresh air in through the intakes.

暖空氣受到浮力作用，在塔內向上流動，並從進氣口吸入新鮮空氣。

But some of that hot water is also evaporated, removing more heat from the water and making the air even more buoyant.

但其中的一些熱水也會被蒸發掉，從水中帶走更多的熱量，使空氣的浮力更大。

The process both cools the water down and creates a natural draft up through the tower, drawing in even more fresh, drier air as it does.

這一過程既能冷卻水，又能在塔內形成自然風，從而吸入更多新鮮乾燥的空氣。

Ignoring the pumps and minor control features, there are no moving parts.

除了水泵和次要的控制功能外，沒有任何活動部件。

字幕列表影片播放

冷卻塔為什麼是這個形狀？ (Why Are Cooling Towers Shaped Like That?)

material

constant

basically

straight