An integration of geothermal energy, waste, and cold energy system employing the technology of organic Rankine cycle

Geothermal energy refers to heat sources from the subsurface of the earth that could be directly utilized in many applications like space heating, aquaculture, greenhouses, snow melting, spas, etc., and to generate power by utilizing the dry, binary, flash, and combined thermodynamic cycle. The value chain of geothermal energy utilization is like the oil and gas production, starting from exploration, exploitation and production. Nevertheless, in the case of distribution, it seems that the geothermal energy might not be freely transported (like oil and gas), and geothermal heat must be utilized immediately at a place where it is extracted. This paper presents the concept, calculation model and thermodynamic analysis of a geothermal power system integrated with a thermal energy storage system using dimethyl ether (DME) as a phase-change material and an Organic Rankine Cycle (ORC) system. The DME appears to be an excellent option for this integration because it is a clean substance produced with syngas that could be obtained from several sources (e.g., coal, methanol, biogas, etc.) and distributed in liquefied form, i.e., the liquefied dimethyl ether (LDME). Since it could be extracted from biogas, the system might exploit biogas production technology from waste. The LDME seems to be an excellent way to distribute the DME as liquefication reduces its volume. It is the similar method as it is widely applied for the liquefication of natural gas (LNG), which could be then used to store cold energy. The cold energy has promising potential to generate power by applying a cryogenic power system based on ORC technology. Thanks to the application of LDME and ORC technology, it could be possible, in a certain sense, to transport the geothermal energy at a distance. Therefore, this integrated method tends to be a promising solution for the energy system and the environment. The advantages of this system are to increase the competitiveness of the geothermal system and the improvement of waste management.     «

Geothermal energy refers to heat sources from the subsurface of the earth that could be directly utilized in many applications like space heating, aquaculture, greenhouses, snow melting, spas, etc., and to generate power by utilizing the dry, binary, flash, and combined thermodynamic cycle. The value chain of geothermal energy utilization is like the oil and gas production, starting from exploration, exploitation and production. Nevertheless, in the case of distribution, it seems that the geothe...     »