Experimental analysis of shallow underground temperature for the assessment of energy efficiency potential of underground wine cellars

Energy saving in production processes is a topical issue in wine sector, where energy demand is mostly due to temperature control. Thus constructive solutions and technological systems that maximize energy efficiency are requested by companies and stakeholders. Underground cellars may represent a solution, as they can provide temperature peaks dampening, thermal wave phase shifting and temperature variation breaking down. The effects depend on building and site features; therefore the knowledge of underground thermal properties and space-time variability of thermal phenomena are fundamental for building design. The objective of the study is to identify time variations of temperature distributions related to ground layers interacting with underground buildings in the wine sector. A monitoring system was implemented and experimental analyses were carried out on two boreholes at different distances from a real underground cellar. Results showed to what extent building design can take advantage of underground thermal properties to minimize energy demand for temperature control. The validity of the standard model of underground temperature distribution was verified for the shallow zone and a procedure was proposed and validated for the assessment of thermal diffusivity. The research represents also a basis for theoretical provisional model definition for surface zones.