This section presents the Life Cycle Inventory (LCI) of the surface technologies developed within the GEOSYN Project. LCI is one of the four phases of Life Cycle Assessment (LCA), as defined by ISO 14040 and ISO 14044:
- Goal and Scope Definition – defines the study purpose, system boundaries, and functional unit.
- Life Cycle Inventory – quantifies inputs and outputs across the life cycle.
- Life Cycle Impact Assessment (LCIA) – evaluates potential environmental impacts and resource use.
- Interpretation – analyses results, limitations, and recommendations.
The GEOSYN LCA aims to demonstrate the environmental sustainability of geothermal energy use for industrial heating and cooling. The assessment will focus on the surface components of the GEOSYN system, using 1 kWhth of thermal energy produced as the functional unit.
The results are intended for researchers, industry stakeholders, policy makers, and the broader public, combining scientific rigor with an accessible presentation of geothermal environmental benefits.
Life Cycle Inventory (LCI) analysis constitutes the data collection phase of the study, encompassing the quantification of all relevant physical flows: inputs in terms of raw resources, materials, semi-finished products, and by-products, as well as outputs in terms of emissions, waste streams, and the final energy product. It is worth emphasizing that the reliability of LCA outcomes is inherently tied to the quality of the underlying inventory data; consequently, access to high-quality, site-specific or design-derived data represents a critical prerequisite for ensuring the robustness of the results.
A widely adopted practice to structure inventory data collection is the distinction between the foreground system, comprising the processes directly under study and potentially influenced by the outcomes of the analysis, and the background system, which encompasses the broader economic activities linked to the foreground through material and energy exchanges. Foreground processes are characterized by primary data, whereas background processes are represented by industry-average datasets sourced from established commercial databases. In this study, foreground data were obtained directly through interaction with RIVACOLD, the industrial partner responsible for the laboratory test installation, who provided inventory data, the P&ID diagram, and component catalogues for all mechanical equipment procured for the system. Background data were sourced from the Ecoinvent 3.10 database currently available on UNIFI. It will be updated to the latest version, Ecoinvent 3.12, during the final stage of processing the results.
The general methodology followed for LCI data collection and modelling can be summarized in the following sequential steps:
- Analysis of the P&ID diagram and identification of the main system components
- Review of catalogues and purchase records for each individual component
- Classification and characterization of each component in terms of size, weight, and constituent materials
- Mapping of material and energy flows to the corresponding datasets available in the Ecoinvent database
- Development of the LCI model within the openLCA software environment
These steps were applied consistently across all mechanical components to generate a dedicated LCI model for each element, representing its manufacturing process. For certain components, the inventory accounts exclusively for the constituent materials, while for others, the energy consumption associated with their production is also included. The inclusion or exclusion of energy flows is determined by the modelling approach adopted for each component, as detailed in the following chapter.
The starting point of the inventory analysis was the characterization of the P&ID diagrams provided for both the Heat Pump system and the Ejector system, as reported in the figures below.
Figure 1: the High Temperature Heat Pump (HTHP) plant diagram layout.
Different colors in Figure 1 represent:
Section A, in red, is the condenser-side cooling circuit and has four main elements: a condenser (CON C), a tank (REC C) equipped with an electric resistance heater (Heater C, HC), and a pump (PC);
Section B, in purple, is the intercooler cooling circuit for the compression train and comprises two dry coolers (DC I and DC 1-2), a tank (REC I) equipped with an electric resistance heater (Heater I, HI), and a pump (PI);
Section C, in green, is the geothermal circuit on the evaporator side and consists of a dry cooler (DC E), a steam generator (SG), and the associated water storage tank from which the steam generator draws water;
Section D, in blue, represents the core of the system, consisting of a High-Temperature Heat Pump cycle operating with four compression stages. The circuit comprises an evaporator (EVAP), an economizer (ECO), a compression train composed of four stages (M1 1ST, 2ST, 3ST, 4ST) with their respective intercoolers (INT 1-2, INT 2-3, INT 3-4), and a condenser (COND). In addition to these primary components, the section includes a storage tank (REC) equipped with an electric resistance heater (HR), fed by a dedicated pump (PIN1).
Figure 2: the Ejector plant diagram layout.
Different colors in Figure 2 represent:
Section A, in orange, is the condenser-side cooling circuit and comprises solely the dry cooler (DC C) and the pump (PC);
Section B, in green, is the geothermal circuit on the heat exchangers side;
Section C, in blue, is the ejector-based system for cold production and comprises the following components: a condenser (COND), two pumps (PH and PE1), a dry cooler (DC H), a heat exchanger (HEX H), a flash separator (REC F), a storage tank (REC), and the ejector (EJ).
More details on the GEOSYN LCI are reported in Project Deliverable 1.4 – Report on Data Collection
Download Table with Life Cycle inventories for HTHP and the Ejector Plants