The Physics Of Keeping Thermal Power Stations Cool

August 10, 2026 by Maya Posch 14 Comments

Recently thermal power stations have been in the news quite a bit, mostly in the context of them being throttled back or shut down due to the river water used to cool them either getting too warm or said river having dropped to a level where it can no longer provide cooling water. Obviously this is a problem, but it helps to understand how we got to this point and what can be done to fix it.

Thermal power stations – also called power plants – come in a wide variety of shapes and sizes, ranging from old-school coal- and gas-fueled power stations to modern nuclear power plants. Something like a concentrated solar power (CSP) station is also a thermal power station, as all of them have a heat source that’s used to generate electricity from, whether that’s a boiler, nuclear reactor core or a big vat of sodium heated up by the Sun via massive mirrors or oil-filled tubes in parabolic throughs.

Except for open-cycle gas turbines (OCGTs) – which are basically jet engines connected to a generator – this thermal energy is then used to generate steam that drives a steam turbine. Once most energy in the steam has been depleted, it has to be condensed back into e.g. water, so that it can be led back to the steam generator. How this condensing step is performed is the question here, with a number of methods available.

Continue reading “The Physics Of Keeping Thermal Power Stations Cool” →

Recovering Water From Cooling Tower Plumes With Plume Abatement

May 22, 2025 by Maya Posch 25 Comments

Electrostatic droplet capture system installed on an HVAC condenser. (Credit: Infinite Cooling)

As a common feature with thermal power plants, cooling towers enable major water savings compared to straight through cooling methods. Even so, the big clouds of water vapor above them are a clear indication of how much cooling water is still effectively lost, with water vapor also having a negative impact on the environment. Using so-called plume abatement the amount of water vapor making it into the environment can be reduced, with recently a trial taking place at a French nuclear power plant.

This trial featured electrostatic droplet capture by US-based Infinite Cooling, which markets it as able to be retrofitted to existing cooling towers and similar systems, including the condensers of office HVAC systems. The basic principle as the name suggests involves capturing the droplets that form as the heated, saturated air leaves the cooling tower, in this case with an electrostatic charge. The captured droplets are then led to a reservoir from which it can be reused in the cooling system. This reduces both the visible plume and the amount of cooling water used.

In a 2021 review article by [Shuo Li] and [M.R. Flynn] in Environmental Fluid Mechanics the different approaches to plume abatement are looked at. Traditional plume abatement designs use parallel streams of air, with the goal being to have condensation commence as early as possible rather than after having been exhausted into the surrounding air. Some methods used a mesh cover to provide a surface to condense on, while a commercially available technology are condensing modules which use counterflow in an air-to-air heat exchanger.

Other commercial solutions include low-profile, forced-draft hybrid cooling towers, yet it seems that electrostatic droplet capture is a rather new addition here. With even purely passive systems already seeing ~10% recapturing of lost cooling water, these active methods may just be the ticket to significantly reduce cooling water needs without being forced to look at (expensive) dry cooling methods.

Top image: The French Chinon nuclear power plant with its low-profile, forced-draft cooling towers. (Credit: EDF/Marc Mourceau)

Exploring The Physics Behind Cooling Towers

November 9, 2024 by Maya Posch 21 Comments

A characteristic of any thermal power plant — whether using coal, gas or spicy nuclear rocks — is that they have a closed steam loop with a condenser section in which the post-turbine steam is re-condensed into water. This water is then led back to the steam generator in the plant. There are many ways to cool the steam in the condenser, including directly drawing in cooling water from a nearby body of water. The most common and more efficient way is to use a cooling tower, with a recent video by [Practical Engineering] explaining the physics behind these.

For the demonstration, a miniature natural draft tower is constructed in the garage from sheets of acrylic. This managed to cool 50 °C water down to 20 °C by merely spraying the hot water onto a mesh that maximizes surface area. The resulting counter-flow means that no fan or the like is needed, and the hyperboloid shape of the cooling tower makes it incredibly strong despite having relatively thin walls.

The use of a natural draft tower makes mostly sense in cooler climates, while in hotter climates having a big cooling lake may make more sense. We covered the various ways to cool thermal plants before, including direct intake, spray ponds, cooling towers and water-free cooling solutions, with the latter becoming a feature of new high-temperature fission reactor designs.

Continue reading “Exploring The Physics Behind Cooling Towers” →

A Swamp Cooler For Burning Man

August 11, 2014 by Matt Terndrup 41 Comments

Swamp%20Cooler%20(4)

For those who don’t know, Burning Man is a week-long festival in the middle of the Black Rock Desert in Nevada. The event attracts a wide range of creative people from all over the world.

This year, [Jake] is going to bring his homemade evaporative ‘swamp cooler’ to help battle the heat. His design uses a medium-sized shipping container with two large holes cut out of it and two 200mm PC cooling fans embedded into the plastic. The fans blow air from the outside into the bin. Humidifier filters sourced from a local dump are inserted into the middle of the container. The filters acts as an absorbent material to hold melt-water being pumped in from another cooler chest above.

A 30 watt solar panel provides enough power to keep the swamp cooler going while giving enough juice to energize decorative LED interior lights along with some backup batteries for phones and cameras. [Jake]’s system contains a re-purposed A/C computer load center for the solar system. He plans to take temperature and humidity readings at the Burn, bringing back the data from the desert to share with the world.

[Jake] does warn about mold with this system though, but one of the advantages with the filters he chose is that they are pretreated with biocidal compounds. This should help to reduce the chance of mold growth. High humidity conditions are also a disadvantage with this type of cooler, but this is a non-issue in the extremely dry desert of The Playa.

If you plan to go to Burning Man, tell about your energy/cooling preparations. Will you be bringing a system similar to this? If so, let us know.

A Do-It-Yourself Air Conditioner With Evaporative Cooling 5 Gallon Bucket

August 8, 2014 by Matt Terndrup 58 Comments

image42-300x225 The people over at Gray Wolf Survival have this amazing little air conditioning project that is a perfect addition to any household that doesn’t have flowing air wafting through. It was created by [Figjam] for a trip to Burning Man, where all kinds of crazy ideas are bred in the hot dry heat of The Playa sun.

The design uses no ice, which is the cooling agent typical found in other DIY air conditioners. Those generally cut holes in the top of a cooler, put a fan on top to blow the air down across the ice. This is similar, but acts more like an evaporative cooler (not really a traditional air conditioner but it does the job).

397648283-300x225 It uses a LOT less energy than an air conditioner unit so there won’t be a need to increase the power capabilities of a simple system to work it, and it can reduce the temperature by up to 30 degrees as well as alleviate the dryness associated with living through a Burn. It runs off 12V DC so it can either use the solar panel or connect to a battery. It has a 12V power plug for this, and draws as little power as absolutely possible. Plus, it has the ability to easily connect to a larger water source so it won’t have to be continually refilled. These considerations make it very portable and perhaps backpackable as well.

[Figjam] took a 5 gallon bucket, wrapped the inside with two layers of swamp cooler matting, made a loop of hose above it connected to a submersible pump and ran a fan out the top with piping. Connecting it to a shelter is done with a vent hose.

A Low Cost, Solar-Powered Swamp Cooler

May 5, 2014 by Marsh 53 Comments

A looming, torturous summer is preparing to bear down on many of us, making this dirt-cheap swamp cooler build an attractive hack to fend off the heat.

Though this is a pretty standard evaporative cooler, the design comes together in a tidy and transportable finished product. The base is a ~$3, 5-gallon bucket from a local hardware store with its accompanying Styrofoam liner. Three 2 1/8″ holes carved into the side of both the bucket and liner will snugly fit some inch-and-a-half PVC pipe with no need for glue.

One last cut into the lid to seat a small desk fan rounds off this build—or you can chop into the styrofoam liner’s lid if you prefer. The video demonstrates using a 15W solar panel to run the fan, and we have to admit that the cooler seems to be an excellent low-cost build. It does, however, require a frozen gallon jug inside to pump out the chilled air for around 5-6 hours per jug. Maybe one of our frugal and mathematically-inclined readers can throw out some guesstimations for the cost of stocking the bucket with a jug of frozen water a couple times a day? Video after the jump.

Continue reading “A Low Cost, Solar-Powered Swamp Cooler” →