How Does A Water Source Heat Pump Work Cooling Tower

A water-source heat pump (WSHP) system with a cooling tower works by using a shared water loop to move heat between multiple heat pumps and the outdoor environment. This setup is very common in commercial buildings.

Below is a clear, step-by-step explanation, tied directly to the cooling tower’s role, how does a water source heat pump work cooling tower.

1. Main Components in a WSHP + Cooling Tower System

* Water-source heat pumps (one per zone)

* Common water loop (closed loop)

* Cooling tower

* Boiler or auxiliary heater

* Circulating pump(s)

* Expansion tank, valves, controls

2. Basic Operating Principle

The system maintains the loop water temperature typically between:

60–90°F (15–32°C)

Each zone’s heat pump can either:

* Reject heat to the loop (cooling mode), or

* Extract heat from the loop (heating mode)

The cooling tower removes excess heat from the loop when needed.

3. Cooling Mode – How the Cooling Tower Works with WSHP

Step-by-Step

1. A zone needs cooling → its WSHP absorbs heat from the room.

2. That heat is transferred to the condenser water loop.

3. Loop water temperature rises.

4. When loop temperature exceeds a setpoint (typically 85–90°F):

  * The cooling tower turns ON.

5. Warm loop water flows to the cooling tower.

6. Heat is rejected to the atmosphere by evaporation + airflow.

7. Cooler water returns to the loop (≈75–85°F).

Result: Loop temperature is controlled so all heat pumps can operate efficiently.

4. Heating Mode – Role of the Cooling Tower

In heating season:

* Some zones may still reject heat (internal loads).

* Other zones extract heat from the loop.

* If loop temperature drops below ~60°F:

 * The boiler adds heat.

* The cooling tower is usually OFF, unless there is excess internal heat.

5. Why a Cooling Tower Is Needed in WSHP Systems

✔ Removes excess building heat

✔ Keeps loop temperature within operating limits

✔ Improves heat pump efficiency

✔ Allows simultaneous heating & cooling

✔ Reduces boiler runtime

 6. Simplified Flow Diagram (Text)

[Zone WSHPs]

    ↓

[Common Water Loop] ← Pump

    ↓

[Cooling Tower] → Heat Rejected to Air

    ↓

Back to Loop

7. Typical Control Strategy

* Tower ON: Loop water > 85–90°F

* Tower OFF: Loop water < 80–85°F

* Boiler ON: Loop water < 60°F

* Two-way valves at each WSHP

* Variable speed pumps often used

 8. Key Differences vs Chiller System

Feature	WSHP + Cooling Tower	Chiller + Cooling Tower
Heat removal	Distributed (each WSHP	Central chiller
Cooling tower role	Loop temperature control	Condenser heat rejection
Energy efficiency	High for mixed loads	Better for large uniform loads
Flexibility	Excellent	Moderate

9. Common Problems & Tips

* Dirty cooling tower → high loop temperature

* Poor water treatment → fouling in WSHP heat exchangers

* Incorrect setpoints → tower runs too often

* Pump oversizing → wasted energy