From production to delivery

The district cooling system (DCS) is made up of collective chilled water production and distribution facilities. Its development relies on pooling the cooling needs of Paris buildings. It is an essential urban planning tool for communities committed to energy efficiency and the fight against climate change.

CLIMESPACE District Cooling System (DCS)

The DCS has enjoyed a distinct success with developers and cities wanting to implement an energy management and greenhouse gas emissions reduction policy. District cooling systems are therefore by nature infrastructures that are closely linked to urban communal or inter-communal development.

In Paris, with CLIMESPACE, chilled water is produced by refrigeration plants and distributed through pipes serving buildings outfitted with energy transfer stations. Each building consumes the amount of cooling energy required for its own needs. The DCS operates in a closed circuit with two conduits; one for conveying the 5°C chilled water to the users and the other for the return of 15°C water to the generation plants.

The DCS thus consists of three basic elements:

Generation plants

A distribution network

Energy transfer stations (ETS)

Principle of CLIMESPACE DCS

Production and storage

The CLIMESPACE chilled water generating plants are made up of refrigeration units that cool the distribution circuit chilled water from 15°C to 5°C. These plants also consist of other equipment such as pumps, electrical equipment.

Energy storage

CLIMESPACE storage systems facilitate response to one-shot and large demands for cooling capacity.

Since cooling requirements are lower at night than during the day, the refrigeration units continue to operate in order to generate cooling energy for storage in tanks. During the day, this stored cooling is used to cover demand peaks.

The cooling energy can be stored in two forms: chilled water or ice. The latter is more advantageous because it can store more energy in a given volume.

Located on the top level of a car park, this installation is made up of 13 tanks storing a total of 12,000 m³ of chilled water, a volume equivalent to an energy of 90 MWh. The water is stored at 3°C.

Distribution

The cooling energy generated by the plant is distributed within each building connected via an inter-connected network. The main CLIMESPACE network, the "Centre" network, lies in the heart of Paris (1st, 2nd, 7th, 8th, 9th and 16th arrondissements). A second network, named the "Bercy" network, serves the 12th and 13th arrondissements.

A 79 km long network

The entire CLIMESPACE network is made up of two separate pipelines, one “outgoing” line that brings chilled water to customers’ distribution stations, the other “return” line taking warmed water to the production plants. The temperature of the chilled water supplied via the “outgoing” line from the production unit ranges from 1 to 4°C. The “return” water comes back between 12 and 14°C.

Entirely underground, the network utilizes the Paris sewage infrastructure or circulates beneath public right of ways. Interconnected, the network is subject to regular, daily monitoring. The CLIMESPACE system offers all customers wide flexibility of use and service reliability.

Control and monitoring

To ensure the continuous supply of cooling and for increased security, the generation plants, distribution network and ETS are managed from a control centre with human presence 24/7. These connected technologies together achieve continuous improvement in energy efficiency. More than 700 energy transfer stations communicate in real time and 115,000 monitoring points are connected to the control centre.

Delivery

Cooling is delivered to users from a main distribution network connection and transmitted to the building’s secondary facilities via an energy transfer station (ETS). Chilled water is primarily intended for building air conditioning and cooling.

The substation is where the ETS is located, in other words all the devices that transfer chilled water from the distribution network to the user’s secondary network.

The ETS role is to transfer the primary fluid frigories to a secondary fluid (by exchange). It adjusts the flow to regulate the departure temperatures and those of the secondary return to the needs of the various users. The cooling energy and volume consumed are metered at the ETS.

The ETS replaces all the facilities required for the stand-alone production of cold, refrigeration units, pumps, air cooling towers… Since an ETS is more compact than a stand-alone installation, the substitution can therefore be assured in any building already equipped with standalone system production.

The ETS installed inside customers’ buildings are “connected” and fully automated.