How A Chiller And Cooling Tower Work

Here’s a clear, easy-to-understand explanation of how a chiller and cooling tower work, both separately and together.

How a Chiller Works

A chiller is a machine that removes heat from water, making cold water that is then used to cool buildings, equipment, or industrial processes.

Main Parts of a Chiller

1. **Evaporator**

  * Warm water from the building flows into the evaporator.

  * Refrigerant absorbs heat from the water, cooling the water down.

  * The refrigerant evaporates (turns into gas) because it absorbs heat.

2. **Compressor**

  * The compressor sucks in the low-pressure refrigerant gas and compresses it.

  * Compression raises the temperature and pressure of the refrigerant.

3. **Condenser**

  * Hot, high-pressure refrigerant goes to the condenser.

  * Here, it releases heat and returns to a liquid state.

  * Depending on the type of chiller:

     Air-cooled chiller: releases heat to outside air with fans.

     Water-cooled chiller: releases heat to condenser water that goes to a cooling tower.

4. **Expansion Valve**

  * Drops the pressure of the refrigerant.

  * The refrigerant becomes cold again and goes back to the evaporator.

   Cycle repeats to make chilled water.

How a Cooling Tower Works

A cooling towe removes heat from the chiller’s condenser water by using air and evaporation.

Steps

1. Hot condenser water from the chiller enters the top of the tower.

2. The water is sprayed over plastic “fill” material to increase surface area.

3. Fans pull or push air through the tower.

4. As the water and air mix, a small portion of water evaporates, removing heat.

5. Cooled water collects at the basin and returns to the chiller.

Evaporation is the key: when water evaporates, it removes a lot of heat.

How a Chiller and Cooling Tower Work Together (Water-Cooled System)

Here is the full loop:

1. The Chiller Side (Cooling the Building)

* The chiller cools chilled water (typically 42–45°F or 6–7°C).

* Chilled water circulates in the building, absorbs heat, and returns warm (around 54–56°F or 12–13°C).

2. The Heat Rejection Side (Cooling Tower Loop)

* The chiller’s condenser absorbs heat from the refrigerant.

* This heat + compressor heat goes into the condenser water.

* Hot condenser water goes to the cooling tower.

* Cooling tower removes heat by air + evaporation.

* Cooler condenser water returns to the chiller.

Simple Analogy

Think of the system like a refrigerator + outdoor radiator:

* Chiller (inside): Makes cold water, like a refrigerator makes cold air.

* Cooling tower: Acts like a giant radiator that dumps heat outside.