How Chiller Works with Cooling Tower

Here’s a clear, simple explanation of how a chiller works together with a cooling tower in an HVAC system:

How a Chiller Works With a Cooling Tower

A chiller and a cooling tower work together to remove heat from a building.

Think of the chiller as the machine that absorbs heat from the building, and the cooling tower as the machine that throws that heat away into the atmosphere.

1. Chilled Water Loop (Inside the Building)

This part cools the building’s air.

1. The evaporator in the chiller receives warm water from the building (called return water ).

2. Refrigerant inside the evaporator absorbs heat from this water → cooling it.

3. The now-cooled water (44–46°F / 7–8°C typically) is pumped back to the building’s AHUs/FCUs to provide cooling.

Result:

Chilled water cools the building, but the chiller must dump that absorbed heat somewhere.

2. Condenser Water Loop (Connecting Chiller → Cooling Tower)

This part moves the heat outdoors.

1. After absorbing heat in the evaporator, the refrigerant moves to the compressor, increasing its temperature and pressure.

2. In the condenser, this hot refrigerant gives its heat to the condenser water (typically 85–95°F / 29–35°C).

3. Condenser water pumps send this hot water up to the cooling tower.

3. Cooling Tower (Rejects Heat to the Atmosphere)

1. Hot condenser water enters the tower at the top.

2. Water trickles down over fill media.

3. A fan draws air upward across the falling water.

4. Some water evaporates → **evaporation removes heat**.

5. Cooled water (usually 75–85°F / 24–29°C) flows back down to the chiller condenser.

Result:

The heat originally inside the building has now been rejected to the outdoor air.

Simple Flow Summary

1. Building heat → Chiller evaporator

Chilled water loop removes heat from inside the building.

2. Chiller → Condenser water

Chiller’s refrigerant rejects that heat to the condenser water.

3. Condenser water → Cooling tower

Cooling tower dumps heat into the atmosphere by evaporation.