Who Invented District Cooling? How Does It Work?
● Today, district cooling systems are taking over the world. District cooling systems' advantages are very high compared to individual cooling systems.
● These systems are reliable and safe, we can use alternative fuels like waste or biomass, it has low emissions levels, peak power saving, and much more.
Before understanding how the system works let's take a look at the timeline of how the system developed over the years:
● Roman hypocausts were the first example of DCS systems. It was a type of hot furnace that was used to heat buildings that were nearby.
● In 1322, hot springs were used to heat several houses and taxes were levied on them.
● This system inspired Dutch polymath Cornelius Drebbel to introduce district heating in London in 1622.
● Bonnemian, a French Engineer heated many large buildings using hot water.
● The Great Exhibition of 1851 became a turning point in the history of DCS systems as a separate boiler plant was set up to provide power to the exhibits in the huge Crystal Palace.
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Institutional buildings in both Europe and America started adopting district heating systems. In 1867, a state capital complex was powered by a heating system and in 1876, Croydon Asylum used hot water.
● The first proper district cooling system was introduced in 1877 by Birds Hill Holy in Lockport, New York, known as the Holly Steam Combination System. The system used boilers as the central heat source. Holly constructed a loop which consisted of radiators, steam pipes and condensate return lines. Within 5 years, the Holly System was installed in 50 cities across Europe and North America.
● Denver Colorado’s Automatic Refrigerator Company installed the first-ever DCS system in 1889.
● In the 1930s, the Rockefeller Center in NY and the Capital Buildings in Washington installed the largest DCS system.
At present, the global market for DCS is dominated by the Middle East and Africa. Why is district cooling an apt system for these regions? The answer is quite simple, it is because of the hot climate in this region.
We all know that cooling is an essential requirement for everyone. A district cooling network is made up of the following components:
1. Chiller plant which cools down water to 4-5 degrees Celsius. It makes use of refrigerants and heat rejection methods including seawater, treated sewage effluents and river water.
2. Water filtration and treatment system helps in preventing the equipment from being damaged by conditioning the recirculated water.
3. Equipment whose main function is to monitor and control the whole system including the pumps and ensure that it achieves adequate temperatures and is responsible for opening and closing the automatic valves.
● Now, this is how the process works- insulated distribution pipes transfer chilled water to various buildings.
● Each building is equipped with an energy transfer station with an interface that consists of valves, meters and pumps.
● A building can reject heat from the chilled water with the help of a simple plate heat exchanger.
● The heated water(13-15 degrees Celsius) returns to the chiller plant after absorbing the heat from the individual building systems.
● This water is filtered, treated and then passed through the chiller where it gets cool and goes back to the buildings.
● Although the process sounds complicated, the cost of a district cooling system is quite affordable and not only that, adopting these systems can also help our planet breathe for a longer time.
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