Thermo-Chemical District Networks

Abstract

Thermo-chemical networks are a new technology for district networks, which can provide heating, cooling and drying in one heat loss-free multiservice network. The innovation is the use of thermo-chemical fluids as transport medium, e.g. in the form of concentrated salt solutions, rather than water. Due to the hygroscopic characteristics of the salt solutions, a chemical potential is transported and not thermal energy as in conventional networks. The chemical potential is used to generate useful heat or cold from ambient heat at the place and time of demand or to dehumidify air for drying or air conditioning processes. An important advantage of this novel technology is that the technology is heat loss-free, which means the thermochemical potential stored in the fluids degrade neither in the piping infrastructures nor in storages. In comparison to conventional district heating networks, thermo-chemical networks can be realized with less investment (no insulation is required) and over longer distances (no heat losses occur). The aspect of heat loss-free storage is also interesting for applications of seasonal thermal storage. In particular with solar energy, allowing shifting the energy available in summer to the wintertime. Thermo-chemical district networks and the possibility of long-term storages will improve the efficiency and profitability of the use of solar energy in district heating networks.

Thermochemical storage networks for integration of renewable energy sources through seasonal load shifting

“…While the project was successful in implementing individual applications such as e.g. humidity and temperature control in greenhouses [6], there are still several unanswered questions about the network as a whole. This includes details of network design, scale-dependent performance, the extension to other terminal applications and process types, including closed sorption processes for energy storage, buffer and seasonal storages, fluid concentration control, as well as the network management thus, more research is necessary.…”