Recent literature works suggest that the implementation of Aquifer Thermal Energy Storage (ATES) systems for heating and cooling purposes can yield reasonable substantial energy savings, leading to a significant reduction in greenhouse gas emissions. Low temperature ATES systems (i.e., operating at low to moderate temperature levels) can act as energy buffers for managing solar, thermal, combined heat and power plants, and intelligent district energy systems. Indeed, evaluating the potential of geothermal resources is a multifaceted challenge requiring interdisciplinary expertise, with reservoir engineering playing a pivotal role. Present study aims to elucidate the influence of inherent shallow aquifer characteristics on the efficiency of installing ATES systems. Our research involves a comparative analysis of performance across diverse subsurface hydrogeological settings through numerical simulations. We perform numerical simulations of ATES in shallow aquifers for three test cases in Milano metropolitan across diverse subsurface hydrogeological settings. Utilizing data collected from three selected locations within the Milan metropolitan Area, we construct simplified box-models of confined aquifers for our three test cases. Simplicity assumption of confined aquifer is not entirely accurate for shallow aquifers in Milan metropolitan area in Italy; for comparison purposes, semi-confined aquifer models are also constructed and tested to assess responses of the ATES system under varying conditions of (i) heterogeneity in rock properties, (ii) aquifer average temperature, (iii) average hydraulic gradient due to aquifer natural flow, (iv) effective rainfall recharge of the aquifer, and (v) the impact of water/air capillary pressure. Our simulations employ in the ECLIPSE 100 (i.e., black-oil formulation of the mathematical models) software environment. To constrain variation of the simulation responses solely to the above-mentioned characteristic parameters of our interest, we maintain consistent well placement and control settings across all comparative test cases. By isolating the influence of key aquifer characteristics on ATES numerical simulations, our research can provide valuable insights into the role of different hydrogeological attributes in the performance, e.g., recovery efficiency, of ATES systems. Our study confirms that simulating a numerical box (confined) model characterized by a homogeneous distribution of permeability/porosity fields can yield notably different recovery efficiencies compared to the open-aquifer simulation model due to the complex interplay of multiple factors, including rock attributes, hydraulic gradients, thermal parameters, temperature fields, effective rainfall recharge, and capillary pressure effects. Our numerical results indicate that heterogeneity of the rock attributes exerts the most significant influence on efficiency of the ATES system. The impact of effective rainfall recharge and capillary pressure within the aquifer varying depending on the specific circumstances, resulting in negligible efficiency changes. Present numerical study can shed light on how various components of hydrogeological characteristics impact the efficiency of ATES systems. This work can constitute a preliminary step toward a comprehensive technical feasibility assessment of installing ATES system in Milano metropolitan.
Pubblicazioni recenti suggeriscono che l'implementazione dei sistemi di Accumulo di Energia Termica in Acquiferi (ATES) per scopi di riscaldamento e raffreddamento può portare a considerevoli risparmi energetici e alla significativa riduzione delle emissioni di gas serra. I sistemi ATES, operanti a temperature basse o moderate, possono agire come accumulatori di energia per la gestione di impianti solari, termici, di cogenerazione e sistemi intelligenti di distribuzione dell'energia. Valutare il potenziale delle risorse geotermiche è una sfida multifattoriale che richiede competenze interdisciplinari, con l'ingegneria dei reservoir che svolge un ruolo fondamentale. Lo scopo del presente studio è chiarire l'influenza delle caratteristiche intrinseche degli acquiferi superficiali sull'efficienza dell'installazione dei sistemi ATES. Questa ricerca comporta un'analisi comparativa delle prestazioni in diverse condizioni idrogeologiche sotterranee attraverso simulazioni numeriche. Sono state effettuate simulazioni numeriche di ATES in acquiferi superficiali per tre casi studio nell'area metropolitana di Milano, con differenti condizioni idrogeologiche sotterranee. Utilizzando dati raccolti da tre località selezionate all'interno dell'Area Metropolitana di Milano, sono stati realizzati modelli semplificati di tipo "box-model" di acquiferi confinati per i tre case-studies. L'assunzione di semi confinamento dell'acquifero non è del tutto accurata per gli acquiferi superficiali nell'Area Metropolitana di Milano in Italia; a fini di confronto, sono stati realizzati e testati anche modelli di acquiferi semi confinati per valutare le risposte del sistema ATES in condizioni variabili di (i) eterogeneità nelle proprietà delle rocce, (ii) temperatura media dell'acquifero, (iii) gradiente idraulico medio dovuto al flusso naturale dell'acquifero, (iv) ricarica effettiva da pioggia dell'acquifero e (v) l'impatto della pressione capillare dell'acqua/aria. Le diverse simulazioni utilizzano il software ECLIPSE 100 (formulazione black-oil). Per limitare la variabilità del risultato, sono stati assunti fissi, in ogni case-study, i pozzi di estrazione e di iniezione in modo da osservare l’impatto dei parametri già citati. Isolando l'influenza delle principali caratteristiche dell'acquifero sulle simulazioni numeriche di ATES, questo studio può fornire preziose informazioni sul ruolo di diversi attributi idrogeologici nelle prestazioni, ad esempio, l'efficienza di recupero, dei sistemi ATES. Lo studio conferma che la eterogeneità delle proprietà delle rocce esercita l'influenza più significativa sull'efficienza del sistema ATES. L'impatto della ricarica effettiva da pioggia e della pressione capillare all'interno dell'acquifero varia a seconda delle circostanze specifiche, comportando cambiamenti di efficienza trascurabili. Lo studio numerico può gettare luce su come varie componenti delle caratteristiche idrogeologiche influenzino l'efficienza dei sistemi ATES. Questo lavoro costituisce un primo passo verso una valutazione completa della fattibilità tecnica dell'installazione del sistema ATES nell'Area Metropolitana di Milano.
Role of Hydrogeological Traits in Numerical Simulation of Aquifer Thermal Energy Storage
MANAFI, MASOUD
2022/2023
Abstract
Recent literature works suggest that the implementation of Aquifer Thermal Energy Storage (ATES) systems for heating and cooling purposes can yield reasonable substantial energy savings, leading to a significant reduction in greenhouse gas emissions. Low temperature ATES systems (i.e., operating at low to moderate temperature levels) can act as energy buffers for managing solar, thermal, combined heat and power plants, and intelligent district energy systems. Indeed, evaluating the potential of geothermal resources is a multifaceted challenge requiring interdisciplinary expertise, with reservoir engineering playing a pivotal role. Present study aims to elucidate the influence of inherent shallow aquifer characteristics on the efficiency of installing ATES systems. Our research involves a comparative analysis of performance across diverse subsurface hydrogeological settings through numerical simulations. We perform numerical simulations of ATES in shallow aquifers for three test cases in Milano metropolitan across diverse subsurface hydrogeological settings. Utilizing data collected from three selected locations within the Milan metropolitan Area, we construct simplified box-models of confined aquifers for our three test cases. Simplicity assumption of confined aquifer is not entirely accurate for shallow aquifers in Milan metropolitan area in Italy; for comparison purposes, semi-confined aquifer models are also constructed and tested to assess responses of the ATES system under varying conditions of (i) heterogeneity in rock properties, (ii) aquifer average temperature, (iii) average hydraulic gradient due to aquifer natural flow, (iv) effective rainfall recharge of the aquifer, and (v) the impact of water/air capillary pressure. Our simulations employ in the ECLIPSE 100 (i.e., black-oil formulation of the mathematical models) software environment. To constrain variation of the simulation responses solely to the above-mentioned characteristic parameters of our interest, we maintain consistent well placement and control settings across all comparative test cases. By isolating the influence of key aquifer characteristics on ATES numerical simulations, our research can provide valuable insights into the role of different hydrogeological attributes in the performance, e.g., recovery efficiency, of ATES systems. Our study confirms that simulating a numerical box (confined) model characterized by a homogeneous distribution of permeability/porosity fields can yield notably different recovery efficiencies compared to the open-aquifer simulation model due to the complex interplay of multiple factors, including rock attributes, hydraulic gradients, thermal parameters, temperature fields, effective rainfall recharge, and capillary pressure effects. Our numerical results indicate that heterogeneity of the rock attributes exerts the most significant influence on efficiency of the ATES system. The impact of effective rainfall recharge and capillary pressure within the aquifer varying depending on the specific circumstances, resulting in negligible efficiency changes. Present numerical study can shed light on how various components of hydrogeological characteristics impact the efficiency of ATES systems. This work can constitute a preliminary step toward a comprehensive technical feasibility assessment of installing ATES system in Milano metropolitan.| File | Dimensione | Formato | |
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Masoud_Manafi_Executive_Summary.pdf
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https://hdl.handle.net/10589/210986