Miraculous solution for ACs planned in Paris

Paris plans to triple system of underground pipes that distribute chilled river water, reducing need for individual cooling units

Here’s a breakdown of how it works and the key components involved.

? How the System Works
This system uses water (not refrigerant) as a medium to transport cooling energy throughout a building. The process is a continuous loop:

Cooling Generation: A central piece of equipment called a chiller produces cold water, typically at around 7°C (45°F) .

Distribution: A chilled water pump pushes this cold water through a network of insulated pipes (the "chilled water piping") from the chiller to various cooling units around the building .

Cooling Delivery: The cold water flows through a coil inside units like Air Handling Units (AHUs) or Fan Coil Units (FCUs) . A fan blows air over this cold coil, cooling and dehumidifying the air before it's sent into the rooms .

Return: The water absorbs heat from the air and warms up, typically to around 12°C (55°F). This warmer water is then pumped back to the chiller to be cooled down again in a closed loop .

?? Key Components and Design Details
The Piping Network: The chilled water is distributed through a network of supply and return pipes. Insulating these pipes is crucial to prevent energy loss and condensation . The system can be designed in two main ways:

Direct Return: The pipes take the shortest path. It's cheaper but can be harder to balance water flow.

Reverse Return: The pipes are routed so that the total pipe length to and from each unit is nearly equal. This makes balancing the water flow much easier but costs more in materials .

Flow Control: To regulate cooling in different areas, each unit (like an AHU or FCU) has an automatic control valve. A thermostat in the room sends a signal to the valve, which opens or closes to allow more or less chilled water to flow through the coil .

Energy Efficiency: In colder seasons, some advanced systems can bypass the chiller entirely. They use the cold outdoor air in a cooling tower to cool the water, a process known as "free cooling," which saves a significant amount of energy
By Jamuna Rangachari