Heating requirements in greenhouse farming in southern Italy: evaluation of ground-source heat pump utilization compared to traditional heating systems

Greenhouse farming, where energy consumptions are mainly related to the greenhouses heating, is one of the sectors consuming the most energy in the agricultural industry. High costs and the uncertain availability of fossil fuels constrain the use of heating applications. Among possible solutions, the utilization of renewable heating systems such as geothermal energy through ground-source heat pump systems (GSHPs) at competitive prices has to be taken in consideration. The competitiveness of these systems depends mainly on the characteristics of the end-users, i.e., the annual heating loads. Few studies focusing on the potential of using these systems start with an analysis of the thermal requirements and end with a cost evaluation in tune with local assets, geo-climatic conditions, and landscape protection. This paper analyzes the greenhouse crop industry in the Apulia region in southern Italy, as a potential end-user of GSHP systems. Data collected from an area mainly devoted to greenhouse crop production have been used to (a) describe greenhouse farms, (b) define the heating requirements of a greenhouse model representative of the most used typology in the investigated area, and (c) examine the economic viability of greenhouse heating with GSHP systems. Both vertical and horizontal ground heat exchanger (GHE) configurations are compared with conventional fossil-fuel heating systems. In all scenarios considered, the observed payback periods appear reasonable and worthy of consideration. The results suggest that these technologies can fully satisfy the winter heating requirements in a costeffective way and they can support the planning of measures aimed to improve the sector competitiveness.