"Water cooler" or "water dispenser" is a device that cools drinking water and makes it available for human consumption. The consumable cold water should be within a temperature range of 10-15 degrees Celsius in moderate regions and 13-18 degrees Celsius in tropical regions.

Water coolers are divided into three categories based on their construction: reservoir-based water coolers, bottle-based water coolers, and instant water coolers. Below, you will find a complete description of the similarities and differences of each of these water coolers.

Reservoir-Based Water Coolers:

These types of water coolers are connected to the plumbing and are connected to the sewer system for draining any excess water that may occur during drinking cold water.

Reservoir-based water coolers usually use a heat pump system to cool drinking water. Operator pipes surround a metal tank. Water enters the tank and is cooled by the cooling circuit using electricity. As water is consumed, the float inside the tank drops, and the inlet water valve opens to fill the tank.

To maintain hygiene, operator pipes must be outside the tank. Additionally, the cooling system's power must be sufficient so that the tank walls do not ice, but the water cools quickly.

Depending on the structural conditions, water coolers should deliver half their tank capacity in one hour. For example, a water cooler with a 300-liter tank should deliver 150 liters of cold water per hour. One of the problems with these types of water coolers is that if water consumption suddenly increases, as mentioned above, cooled water exits the tank, and warm water replaces it through the float valve. Therefore, the rate of cold water consumption is inversely related to the water temperature. This means that the more water we consume, the gradually warmer the water we receive.

Bottle-Based Water Coolers:

The source of consumable water for reservoir-based water coolers is supplied by a large bottle that is inverted on the device and, after being emptied, must be replaced with a bottle full of water. These water coolers also use a heat pump, but the operator is plate-shaped, separate from the tank, and cools the water with less volume by placing it on the plate. Bottle-based water coolers (fancy) are suitable for use in places with low water consumption.

Instant Water Coolers:

The instant water cooler was invented in 2007. The cooling system of instant water coolers is a heat pump; however, the drinking water tank has been eliminated in this system. These water coolers operate instantly and cool the water at the moment. For this reason, with an increase in the rate of water consumption, the water temperature does not increase, so the cold water temperature remains constant between 9-13 degrees Celsius even during peak water consumption hours.