Ground Storage is considered a powerful solution for supplying thermal energy for H&C of buildings. MESSIB Project has tackled the development of this technology in order to enhance the current status of the technology and integrate those systems into buildings together with other energy solutions considered in the project. Ground Storage can mainly supply thermal energy to be used for H&C of the buildings and SHW covering the energy demand of buildings by means of extract or inject heat in the ground. The behaviour of the ground in those systems is considered as a thermal reservoir, and, subsequently the thermal characteristics of the ground will determine the efficiency of the geothermal systems.

Messib project has been focused on different aspects to assure the enhancement of the ground storage.

1. Design and development of new methods for measuring the soil conditions in order to facilitate the understanding of the ground as a thermal reservoir. The temperature conditions of the ground and the thermal conductivity determinate the heat transfer from the heat exchangers to the ground and vice versa. Those parameters are usually inferred from thermal response tests but can be completed using the techniques developed within MESSIB Framework using temperature sensors and measuring the thermal conductivity of the different lithologies using the cores and cuttings extracted during the drilling stage.

2. Optimization of the ground for thermal storage purposes by means of inject inert mineral materials which could enhance the thermal conductivity of the grounds. The development of those materials has been obtained within the development of the project and the thermal conductivity of the grounds has been increased from average values of 2 to 4 w/mK. The enhancement produces a better transfer of the heat from the exchangers to the ground. It also permits to increase the effective area of heat transfer with a positive repercussion on the efficiency of the installation. The efficacy of the actuation will be tested and demonstrated in a pilot plant which will be placed at Paterna (Spain).

3. Development of new enhanced pipelines systems to increase the performance of the geotermal systems. This system will permit a better exchange process between the exchangers and the ground.

BTES (Borehole Thermal Energy Storage)