How Does Cold Water Air Conditioning Work?

There are many places around the United States where summer temperatures necessitate air conditioning to maintain comfortable conditions. Depending on where you live, your home might require air conditioning throughout the year. No matter what climate you live in, however, central air is an essential element in most homes. Central air is also needed for comfort control in many businesses, stores, schools, and office buildings. In many instances, larger buildings require much larger HVAC systems than residential homes. As a result, you might find larger chilled water air conditioners in commercial settings.

While chilled water HVAC systems are standard in commercial properties, many homeowners are also beginning to realize the benefits of these systems. Chilled water systems differ from standard air conditioners in that they rely on cold water instead of refrigerant to cool air. Even though many aren’t familiar with chilled water systems, the idea has been around since the time of the ancient Romans. The Romans would run cold water through the walls to help lower the indoor temperature to cool their buildings. More recently, Willis Carrier invented the first centrifugal chiller in 1926 that made it possible to provide air conditioning on a larger scale.

While chillers have undergone many changes and innovations since 1926, the basic principle of removing heat from water remains the same. Cold water air conditioning relies on chiller units to cool the water that ultimately produces cold air coming from the vents. Let’s take a closer look at chilled water systems.

How does a chilled water system work?

As discussed, a chilled water system relies on cold water circulation to provide cool air. While standard HVAC units circulate a refrigerant to absorb heat and provide cool air, a chilled water unit sends cold water around to do the same job. The water absorbs heat from the house and releases it outside, just like a standard unit. The system consists of pipes and pumps to move chilled water around the building. The chilling unit cools the water in the system down to around 40 degrees and then sends it to the air handler equipment.

As the cold water is pumped through the water coil’s air handler, the coil is cooled, and the water absorbs the heat and humidity from the air being drawn in by the fan. As the air moves across the cooled coil, it cools down and circulates through your air ducts and vents. The system pumps the heated water outside, where the heat and humidity are released into the air, and the water is cooled again. This process continues until the house reaches the temperature set on the thermostat.

How do chilled water systems work in commercial buildings?

With the invention of the chiller, commercial buildings could have a quality air conditioning system. While chilled water systems are finding their way into some residential properties, they are predominantly used in commercial settings. A chilled water system relies on an outside chiller unit and cooling tower in buildings like schools, shopping malls, hotels, and offices. In many instances, the chiller is mounted on the roof. Like the residential system, the chiller cools the water to around 40 degrees and performs a similar operation as your home’s system. The cooling tower helps with efficiency by creating a stream of cool water.

Different areas or rooms might have their own temperature controls in large commercial buildings. Cool water flows from individual chillers or a centralized chiller plant in these instances. Often, a central chiller is used as a more practical way of cooling multiple spaces or buildings without requiring several pieces of equipment in different locations.

Chilled water systems are more common for large systems that service bigger properties. However, water chilled systems that rely on a chiller unit are becoming more popular even in smaller homes. Water systems can cost more up front but will be more efficient and require less maintenance in the long run.