1,720,961 research outputs found
Untapping Industrial Flexibility via Waste Heat-Driven Pumped Thermal Energy Storage Systems
No full textPumped thermal energy storage (PTES) is a promising long-duration energy storage technology. Nevertheless, PTES shows intermediate round-trip efficiency (RTE—0.5 ÷ 0.7) and significant CAPEX. sCO2 heat pumps and power cycles could reduce PTES CAPEX, particularly via reversible and flexible machines. Furthermore, the possibility to exploit freely available heat sources (such as waste heat and/or CSP inputs) could increase RTE, making the system capable of an apparent RTE > 100% as well as reducing CAPEX, avoiding the need for two TES systems. This paper analyses the potential valorization of industrial waste heat (WH) to enhance PTES thermodynamic performance as well as increase industrial energy efficiency, valorizing different levels of WH sources in the 100–400 °C temperature range. In fact, the use of additional heat, otherwise dumped into ambient surroundings, may contribute to avoiding the need for a second TES, thus enhancing plant competitiveness. Starting from an assessment of the most relevant industrial sectors to apply the proposed solution (looking at available WH and electric flexibility needed), this paper analyses the feasibility of a specific sCO2-based PTES case study, where the cycle is integrated into a cement production plant with a WH temperature of around 350 °C. It is demonstrated that the CAPEX of the proposed systems are still relevant and only a robust exploitation of the PTES in the ancillary service market could attract industrial customers’ interest in sCO2 PTES
Thermo-economic performance evaluation of thermally integrated Carnot battery(TI-PTES) for freely available heat sources
No full textIn a scenario driven by non-programmable renewable energy sources (RES) being integrated into the grid, there is a critical need for large-scale energy storage solutions for maintaining grid stability and providing services of frequency regulation as being currently provided by conventional thermal power plants. Among various options, Carnot batteries stand out for their ability to provide GWh scale storage without geographical limitations, at reasonable costs, integrating power to heat to power technologies to thermal energy storage (TES), however at the cost of relatively low Round Trip Efficiencies (RTE). This study delves into a new concept in Carnot battery called Thermally Integrated Pumped Thermal Electricity Storage (TI-PTES) utilizing sCO2 heat pump and power cycles. Thermal integration of heat source in the charging cycle leads to attractive Round Trip Efficiency(RTE) values as compared to conventional PTES. Additionally, using supercritical carbon dioxide (sCO2) as a working fluid offers several advantages of compact designs leading to reduced overall footprint compared to other fluid-based technologies. The study analyzes thermo-economic performance of sCO2 based TI-PTES using an in-house tool WTEMP-EVO; for integration of various industrial and renewable heat sources into the PTES system while exploiting market available thermal energy storage options through a mapping approach
Turbomachinery Design and Part-Load Operation Analysis of a Supercritical CO2 Cycle-Based Thermally Integrated Pumped Thermal Energy Storage Experimental Test Rig
No full textTechno-Economic Assessment of CO2-Based Power to Heat to Power Systems for Industrial Applications
No full textThe industrial sector is a major source of wealth, producing about one-quarter of the global gross product. However, industry is also a major emitter of CO2 and it represents a key challenge toward achieving the worldwide CO2 emission reduction targets. Nowadays, about 22% of the overall energy demand is heating for the industrial sector, generating about 40% of the global CO2 emissions. Additionally, 30% of the final energy demand of the industrial sector is electricity. Solutions to decarbonize the industrial sector are needed. This work presents the techno-economic assessment of four different molten salts-based power-to-heat-to-heat and power solutions aiming at decarbonizing the industrial sector, requiring medium temperature heat. The systems are studied under different electric markets. Dispatch strategies and system sizing are identified to ensure optimal techno-economic performance. The main performance indicators investigated are the levelized cost of heat and electricity (LCoH and LCoE), the operational expenditure, and the attainable savings with respect to alternative business as usual solutions. The results highlight that the proposed system can be cost-competitive, particularly in markets characterized by low electricity prices and high daily price fluctuations, such as Finland. In these locations, LCoE as low as 100 e/MWh and LCoH lower than 55 e/MWh can be attained by the base system configuration. The introduction of high temperature heat pumps can provide further LCoH reduction of about 50%. This study sets the ground for further power-to-heat-to-heat and power techno-economic investigations addressing different industrial sectors and identifies main system design strategies
SCO2 BASED PUMPED HEAT THERMAL ENERGY STORAGE SYSTEMS VALORIZING INDUSTRIAL WASTE HEAT RECOVERY: A TECHNO-ECONOMIC ANALYSIS OF THE ROLE OF HIGH TEMPERATURE TES
No full textIn the current renewable energy dominated power system, as power production is becoming more and more unpredictable, it would be important to act at two levels: integrating relevant power/energy capacity of energy storage and making demand more controllable. At this purpose, acting on industrial energy demand via integration of energy storage and electrification of local processes, could provide a significant contribution. At the same time, waste heat recovery (WHR) is quite a consolidated industrial practise. Nevertheless, WH valorisation is usually performed via bottoming cycles, such as steam, ORC or supercritical CO2 (sCO2) power cycles. The development of thermo-mechanical storages to be installed at industrial level, can contribute in this direction through the use of traditional technologies (rotating machinery) employed in power plants as well as in Waste-heat-to-power (WH2P) plants. This paper presents a thermo-economic analysis of Pumped Thermal Energy Storages (PTES) for sCO2 cycles, comparing market available thermal energy storage materials for different temperature range of operation. The proposed system is purposefully designed to exploit the waste heat sources for the temperature ranges of 150-400°C, difficult to exploit for WH2P solutions and rarely addressed in literature so far. The use of sCO2 enhances the techno-economic features of these systems, the independent charging and discharging system proposed in this study can also provide a keen sense of flexibility especially for the upscaling of a PTES plant to reach an equal grid flexibility power for charging and discharging. At the same time, the valorisation of low temperature waste heat enables industries to enhance their energy efficiency, limit their operational costs and environmental impact, whilst becoming an active part in the regulation of the grid. At this purpose optimal system configurations and dispatch strategies are identified based on typical load curves of specific EU markets. Starting from an identified reference case (a cement production plant with WH temperature to be valorized around 330°C), different PTES cycle layouts and TES technological solutions are compared on a techno-economic basis. The waste heat integration to the PTES system has been found to add satisfactory value in terms of RTE. On the other hand, it proves to be an optimal use case of waste heat valorisation than traditional waste heat to power cycles when compared in terms of exergy, capital cost and dispatchability in ever increasing RES penetration scenarios. The identification of the most optimal TES however is driven by economic factors too as presented in CAPEX and dispatchability analysis
Multicriteria Optimization and Comparison of ACAES and PTES for Long Duration Energy Storage Market
No full textTECHNO-ECONOMIC ASSESSMENT OF CO2 BASED POWER TO HEAT TO POWER SYSTEMS FOR INDUSTRIAL APPLICATIONS
No full textThe industrial sector is a major source of wealth, producing about one-quarter of the global gross product. However, industry is also a major emitter of CO2 and it represents a key challenge towards achieving the worldwide CO2 emission reduction targets. Nowadays, about 22 % of the overall energy demand is heating for the industrial sector, generating about 40 % of the global CO2 emissions. Additionally, 30 % of the final energy demand of the industrial sector is electricity. Solutions to decarbonize the industrial sector are needed. This work presents the techno-economic assessment of four different molten salts based power-to-heat-to-heat and power solutions aiming at decarbonizing the industrial sector, requiring medium temperature heat. The systems are studied under different electric markets. Dispatch strategies and system sizing are identified to ensure optimal techno-economic performance. The main performance indicators investigated are the levelized cost of heat and electricity (LCoH and LCoE), the operational expenditure, and the attainable savings with respect to alternative business as usual solutions. The results highlight that the proposed system can be cost-competitive, particularly in markets characterized by low electricity prices and high daily price fluctuations, such as Finland. In these locations LCoE as low as 100 €/MWh and LCoH lower than 55 €/MWh can be attained by the base system configuration. The introduction of high temperature heat pumps can provide further LCoH reduction of about 50 %. This study sets the ground for further power-to-heat-to-heat and power techno-economic investigations addressing different industrial sectors and identifies main system design strategies
A NOVEL THERMALLY INTEGRATED CO2-CARNOT BATTERY UTILIZING COLD THERMAL STORAGE
No full textThe growing integration of renewable energy sources in the energy grid presents challenges related to intermittency and negative pricing, necessitating large-scale energy storage solutions. Pumped Thermal Energy Storage (PTES) is an innovative system designed to address these issues by storing and delivering substantial energy in the form of heat using thermal heat pump and power cycles respectively. High temperature heat pump development is crucial to the deployment of PTES as it needs to store heat at > 450°C above the ambient temperature to ensure a reasonable round trip efficiency (RTE). Currently however, it is not a technological possibility for heat pump machinery to achieve these temperatures even with integration of freely available heat sources (200°C to 400°C) which can support the heat pump cycle from a RTE standpoint. This study explores a potential layout of TI-PTES system that exploits commercially available equipment by storing heat below the ambient temperature while still being able utilize the freely available heat source (Solar, Waste heat, biomass etc.) to support the overall RTE, in the power cycle instead. The charging phase employs a well-established CO2-refrigeration cycle to accumulate energy below the ambient temperature in a cold thermal storage. While the discharging phase runs a trans-critical CO2 power cycle between the freely available heat source and the cold thermal storage. Overall, offering a practically implementable model for the PTES system with market available components. The study investigates design of this innovative system presenting the relevance of different operating and machine parameters as well as the contribution of freely available heat source in the overall performance. Finally benchmarking the technology with other long duration energy storages
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