History of the chiller: from the ice trade to today's water chillers

The history of the chiller begins with natural ice cut from lakes in winter and shipped across the sea, and it takes its present form at the start of the 20th century with the idea of cooling water in a machine and distributing it through a building. The turning points are these: in the 1750s, experiments showed that evaporation cools; in 1834, Jacob Perkins built a closed-circuit vapour compression machine; in the 1870s, Carl von Linde built ammonia refrigeration machines; in 1902, Willis Carrier designed the first modern air conditioning system; and in 1922, Carrier introduced the centrifugal refrigeration machine for large buildings. Today's units carry the same idea forward with inverter control and low-GWP refrigerants.

This article focuses on history. You can read how the machine works today in our sister company's article what a chiller is.

Before machines: snow pits and the ice trade

The need to store cold is far older than any machine. In Iran, domed ice houses, and in Anatolia, snow pits, carried the snow and ice gathered in winter through to summer under layers of straw and earth. In Ottoman Istanbul, snow brought down from Mount Uludağ is said to have been used to chill sherbet.

In the 19th century this became a trade. In 1806, the Boston merchant Frederic Tudor sent ice cut from New England lakes to Martinique in the Caribbean; over the following decades, ice travelled as far as India in sawdust-insulated stores and ship holds. Norway also sold ice cut from its lakes to England. The limits of natural ice were clear, though: a mild winter cut supply, ice that melted on the way became waste, and the temperature could not be controlled.

Evaporation cools: the first experiments

The observation behind artificial refrigeration is simple: a liquid draws heat from its surroundings as it evaporates. In the 1750s at the University of Glasgow, William Cullen evaporated ether under low pressure and obtained a small amount of ice. In 1758 in Cambridge, Benjamin Franklin and John Hadley repeatedly wetted the bulb of a thermometer with ether and let it evaporate, bringing the temperature well below the freezing point of water.

These experiments did not yet become a useful machine. But for the first time they made measurable what happens in the evaporator of every refrigeration cycle today: cold could be produced by evaporating a fluid. What was missing was a way to collect the evaporated fluid and use it again.

Closed-circuit machines: 1834 to the 1870s

Turning the evaporated fluid back into liquid and reusing it, instead of releasing it into the air, was the key to continuous refrigeration. In 1834, Jacob Perkins, an American inventor working in London, patented a closed-circuit vapour compression refrigeration machine running on ether. The fluid evaporated, a pump compressed the vapour, and the compressed vapour condensed back into liquid. The cycle of today's chillers rests on the same steps.

In the years that followed, different routes were tried:

• In the United States, the physician John Gorrie developed an ice machine that compressed and expanded air to cool the rooms of malaria and yellow fever patients, and patented it in 1851.
• In Australia, James Harrison started commercial ice production and the cooling of beer and meat with ether machines in the 1850s.
• In France, Ferdinand Carré developed, at the end of the 1850s, an absorption machine that ran on ammonia and water and was driven by heat instead of a compressor. We describe the modern counterpart of this cycle in our article on the absorption heat pump.

In the 1870s in Munich, Carl von Linde developed efficient vapour compression machines running on ammonia. His first major customers were breweries: lager, fermented in the cold, needed a low and constant temperature in summer and winter alike. Cold no longer depended on winter. From the beginning of the 20th century, the natural ice trade gave way to factory-made ice and refrigeration machines.

1902: Carrier and humidity control

The road to what we now call a chiller opened with a printing plant's problem. At the Sackett-Wilhelms printing works in Brooklyn, summer humidity made the paper expand, and colours did not print in register. In 1902, the young engineer Willis Carrier designed a system that passed air over coils carrying cold water, controlling both its temperature and its humidity. This system is considered the first modern air conditioning installation, and it is no coincidence that its first user was a factory.

The decisive step for large buildings came twenty years later. In 1922, Carrier introduced the centrifugal refrigeration machine: it worked with a safer refrigerant than the earlier ammonia machines and could cool large quantities of water in one central place. The chilled water was piped to coils in the halls. In the 1920s, cinemas and theatres were among the first large users of these systems. Cooling water in a central machine and distributing it through a building is still the basic job of a chiller today.

Refrigerants: from ammonia to low GWP

The first refrigeration machines used fluids such as ammonia, sulphur dioxide and methyl chloride. These were either toxic or flammable, and leaks could cause serious accidents. At the end of the 1920s, Thomas Midgley and his team developed chlorofluorocarbons (CFCs, sold as Freon), which were neither toxic nor flammable. From the 1930s on, CFCs allowed refrigeration and air conditioning to spread to a wide public.

In the 1970s it became clear that CFCs damage the ozone layer; the Montreal Protocol, signed in 1987, began their gradual phase-out. First came HCFCs such as R22, then HFCs such as R134a and R410A, which do not harm the ozone layer. HFCs, however, had a high global warming potential; the Kigali Amendment of 2016 put their reduction on a timetable in turn. Today, chillers increasingly use R513A, with a lower GWP than R134a, and R1234ze, with a very low GWP, while heat pumps turn to natural refrigerants such as R290. We compare the climate impact of refrigerants in our article on the environmental impact of heat pumps.

From buildings to factories

Chilled water soon left buildings as well. In the 1930s, during the construction of the Hoover Dam, the temperature of the mass concrete was controlled with water passed through pipes embedded in the blocks; pipe cooling is still used in large pours today. In the second half of the 20th century, as plastic injection moulding and extrusion spread, chilled water that keeps moulds at a constant temperature became part of production. Food, pharmaceutical and chemical plants tied product quality to water temperature; in later decades, server rooms and data centres joined the list.

We cover two of these applications separately: injection moulding machine cooling and concrete cooling.

Today's chiller

Today's units carry the same idea as Carrier's machine but are the product of a different technology. In most applications, reciprocating compressors have given way to scroll, screw and centrifugal compressors; our sister company's article on compressors explains the differences. The main direction of change, however, has been control:

• Inverter and variable frequency drives adjust capacity to the load without steps; part-load efficiency has become as important as full-load efficiency.
• Microprocessor control can hold the water temperature within a ±0.5 °C band in process applications.
• Units connect to building and plant automation through Modbus, BACnet or SCADA and are monitored remotely.
• Free-cooling coils stop the compressor in winter and cool the water with outside air.
• Heat recovery turns the heat rejected by the condenser into domestic hot water.
• Small units arrive with the pump and tank inside the casing, factory-charged with refrigerant and tested; they can run on the day power and water are connected.

The story of the same cycle on the heating side took a separate path; we tell it in our article on the history of the heat pump.

Today's options

From the 5–60 kW mini chiller that serves a single machine, through 50–500 kW commercial units for hotels and hospitals, to 300–2,000 kW industrial chiller units for production lines, you can find today's range of sizes on our chiller units page. We have collected the steps for finding the right unit for your project in our chiller selection article, and you can send us your requirements through our quotation form.