Pumped-Steam Generators, or PSGs, are being used for a variety of energy and water projects around the globe, and it’s a prime example of how thermal technology can improve the efficiency of power and cooling facilities.
Whether you’re looking at upgrading a central facility for schools, heating a concrete factory, or adjusting a cooling tower, a thermal upgrade makes the process much faster and more efficient. And it’s no longer just thermal-power engineers who think this way, as we’ve just published research showing the overall benefits of thermal upgrades in power plants.
The benefits of thermal upgrades are usually worth several times the cost. Thermal upgrades in power plants can reduce carbon emissions by 35–65%, depending on whether it’s a combined thermal-power facility or just the steam turbine, and by 60–95% in cooling towers. And PSGs can add a further 20% to 40% efficiency improvement.
Most cooling towers in power plants use steam that runs into a reciprocating pump, which passes the liquid over a rotating and cooling nozzle to release the water. This process uses hundreds of kilograms of steam per minute. Unlike traditional thermal plants, which use coal or natural gas to generate electricity, cooling towers may require Uranium Production to produce electricity.
And while cooling towers are essential to power plants, they are also used in many industries such as steel mills and chemical plants, as well as in domestic and commercial buildings.
It’s hard to estimate how many cooling towers are used across the world. The Environment Agency’s greenhouse gas emissions database is the only worldwide resource that provides these data, but it only includes facilities located in Europe.
One way we estimate the global market share of cooling towers is by using data from the ASME PEX Power Data Book, which reports on power plants, cooling towers, and thermal plants. We used this to categorize the world’s 25,841 cooling towers by their final operating efficiency, heat content, PSG technology, and the geographic location where they are located.
Let’s start by looking at the heat content of cooling towers. Every ton of cooling tower is about 3.9 tons of air and heat content in the form of water that flows into the cooling tower. The heat content of the cooling towers increases with their final cooling capacity and PSG technology, as shown below.
And although PSGs make cooling towers more efficient in a power plant setting, they actually improve heat content even more in cooling tower engineering technologies that don’t use PSGs, due to the improved efficiency of the cooling tower and a reduction in the pump energy required.
Of course, PSGs aren’t always the best option. And power plants are expensive to build. Thermal upgrades are often needed. The advantage is that the cooling plant itself doesn’t need to be replaced, and the power plant can continue to operate while the process equipment is upgraded.
In most cases, power plants are large, with many cooling towers and lots of equipment, such as boilers and turbines. If a power plant only needs one cooling tower, upgrading it would often be much more cost-effective. When a power plant is located close to another plant, it may make sense to have one of the units near it converted as well.