A cycling enthusiast’s guide to evaporative cooling

August 24, 2020

By Paul Walsh, General Manager, CIM EMEANow I don’t claim to be an elite cyclist by any stretch of the imagination but I do enjoy a good spin at the weekends with my Borrisoleigh cycling club teammates. We’ve successfully slogged up some of Europe's famous hills including Le Tourmalet, Colombier, Healy Pass and The Vee. All of these climbs involve cycling up a constant gradient of anywhere between 5% and 13% per kilometre for more than 20 kilometres. These hills are always challenging, especially for an amateur cyclist like myself, but the huffing and puffing is always worth it when we reach the top, take in the stunning views and replenish our energy stores with a sneaky snickers! Once we’ve rested and regrouped, we start our descent, the part of the ride that intrigues me the most due to how cold I feel on the way down.I used to watch the Le Tour de France in the 1990’s and wonder why the pro racers would stuff newspapers down their tops when they reached the summit. Prior to joining CIM, I'd not taken the time to understand why. It was only recently, after I started working with CIM and took a refrigeration course that the puzzle pieces finally fell into place. I fact-checked my theory with CIM’s head of engineering, Tony Mickaeal, who confirmed that I am experiencing a thermodynamic principle called ‘latent heat of evaporation’. This occurs when liquid water changes into water vapour. In my case, this was occurring when the water (sweat) in my clothes evaporated due to high velocity, low humidity warm air coming into contact with my sweat-soaked top as I sped down the hill. As the water evaporates from a liquid to a gas, it absorbs heat from my body, which explains why I am always freezing by the time I make it down the hill.

Evaporative cooling is the oldest form of cooling and has been around for many centuries. Examples of such systems have been found in the archaeological remains of societies such as ancient Egypt and Rome. It’s well suited for climates where the air is hot and humidity is low. Modern evaporative air coolers are compact, well designed and efficient; they provide comfort cooling at a far lower electrical demand and emit less greenhouse gases into the atmosphere.Whilst they are an energy effective cooling technology, these systems do have the tendency to consume a significant amount of water. Building analytics helps identify opportunities to reduce water consumption in modern evaporative coolers, ensuring the system is both energy and water efficient.It’s satisfying to connect the fascinating parts of a social cycle on the weekends to the engineering principles for heating, ventilation and air conditioning systems (HVAC) that I learn more about in my job. Every day at CIM is really a day at school.Have you got a question for our HVAC experts? Get in touch with us today.

CIM Team
August 24, 2020