Thermal energy distribution networks are important components of the territorial energy system. Yet, despite the technological advances of 5 successive generations of networks, the basic principle - circulation of a single-phase fluid with sensible heat exchange - has remained unchanged. The aim of this project is to simulate and experiment an innovative 6th generation heat and cold distribution network, the CO2 network.
The principle of the first heat distribution network, dating from the 14th century, has remained unchanged for 4 technological generations: the production of energy-heat distributed by a single-phase fluid with a high temperature difference with the environment. This system is characterized by a single service (heating or cooling), fixed producer and consumer roles (no interaction), high temperature differences between the fluid and the environment (losses), and a medium energy density imposing diameters unsuitable for urban deployment. As an alternative, the 5th generation network - aenergie network - distributes cold water (ambient temperature 10 to 25°C). This water is fed to heat or cold pumps (heat pumps or refrigeration systems, respectively) that raise or lower the temperature of the power-heat to provide the required energy service. The decrease in the temperature of the network has reduced the thermal losses, but has caused a decrease of its energy density, which is compensated by the increase of the diameter of the network pipes. This makes the network even less suitable for the urban environments, where the subsoil is already overexploited and major road works have a strong impact on the local economy. In order to solve this problem, the 6th generation network has been developed, the CO2 network. This network uses a heat transfer fluid in liquid and vapor phases (two-phase system) and uses the enthalpy of vaporization and/or condensation to exchange its heat. This system combines the advantages of all previous generations. By exploiting the energy density associated with phase change, this network uses a more compact pipe diameter, which is easier to deploy, in particular in urban areas.
As this is a new technology, there is no digital model or physical installation. However, it is important to have an experimental tool to study, in a simple and secure way, the behaviour of the network and its components under different demand profiles. In the same way, a numerical tool must allow the optimisation the experimental approaches.
The aim of this project is to study the dynamic behaviour, through simulation and experimentation, of an innovative 6th generation heat and cold distribution network, the CO2 network. The objectives are
a) to characterize and transpose a case study in order
b) to model and simulate it numerically,
c) to emulate its operation experimentally with a scaled-up installation, and
d) to valorize and disseminate the results.
The knowledge developed will allow us to understand the dynamics of such a network, especially in view of the stochastic interactions between producers/consumers and between thermal and electrical networks. The components of the network will also be mastered. Finally, the experience gained will allow the consortium to continue its collaboration and to undertake the design, deployment and technical-scientific support of systems in the context of future larger-scale projects.
The ROADMAP project covers the entire value chain of the CO2 energy network technology: numerical simulation, design and construction, experimental laboratory emulation and full-scale demonstrator.
Project partner(s)
Project leader - team
Ricardo Lima
(HEPIA)