Experimental analysis of thermal properties of tuff from the Campania region in Italy for the design and performance assessment of ground energy systems

Accurate knowledge of the ground thermal properties is fundamental in de-signing and assessing the performance of ground energy systems (i.e., sys-tems using the ground as a heat source or sink), such as solar plants integrat-ed with seasonal borehole thermal energy storages or geothermal heat pumps. Tuff is one of the materials most easily found in the ground of the Campania region (southern Italy). The Transient Plane Source method is a widely used technique for character-izing the thermal properties of an extensive range of materials in a short time. In this study, the thermal properties of the following two different types of tuff, taken from the ground of the Campania region, have been investigated in the “Built environment control laboratory RIAS” of the Department of Ar-chitecture and Industrial Design of the University of Campania Luigi Van-vitelli: 1) “yellow tuff” from the city of Dugenta; 2) “light yellowish brown tuff” from the city of Sant’Agata de’Goti. In particular, the values of thermal conductivity, thermal diffusivity and volumetric specific heat have been measured via the Hot Disk Thermal Constants Analyser TPS 1000 (based on the Transient Plane Source method) with the aim of providing new and de-tailed data to analyze and support the development of ground energy sys-tems. The experimental data have been compared with the values available in the scientific literature for similar materials; the comparison highlighted how the thermal properties of tuff are significantly influenced by the place from which the samples are collected as well as the measurement method.