Heat Recovery Research Articles

Does the Novel Dual Source Heat Pump (DSHP) Out-Perform the Ideal DSHP? Experimentation Versus Simulation of DSHP Based Thermodynamic Irreversibility of the Throttle Valve

Purpose: The air-source heat pumps are associated with continuous frosting problems. To ensure a more energy efficiency technology, the novel dual-source heat pump (DSHP) was developed. This article aims to confirm and compare the energy performance of the novel dual-source heat pump (DSHP) with the performance of an ideal heat pump. Methods: We applied an experimental analysis from an installed DSHP system with converters and other components to obtain the energy performance of the DSHP, while the performance of an ideal pump was obtained from simulation based on the theoretical algorithm of the basic principle of the thermodynamic irreversibility of the throttle valve. Results: We found that the Ideal (simulated) DSHP has a higher coefficient of performance (COP) than the installed (experimented) DSHP. The Ideal DSHP’s COP of 4.52 is higher than the Novel DSHP’s COP, which range from 1.78 (day 3) to 2.01 (day 1). The DSHP are power efficient, which reduces carbon emission from whatever power source that is been used. Implications: Energy efficiency in buildings has severe implications for global warmings and the need for sustainability. Because the modern ventilation system utilise energy from waste and heat recovery to power heating and cooling systems, the DSHP remains promising for future generations of building ventilation design. Originality/Value: The value of the study is because it completes an experiment that analyse the performance of the DSHP, comparing the outcomes with results from a simulation based on an Ideal system.

Using AI to Increase Heat Exchanger Efficiency: An Extensive Analysis of Innovations and Uses

Artificial intelligence (AI) has made significant strides toward cost reduction and performance optimization in heat exchanger technologies. Artificial intelligence (AI) methods in machine learning, deep learning, and expert systems provide significant advancements in diagnostics, performance optimization, and predictive maintenance. While deep learning is superior at recognizing intricate patterns, machine learning offers flexibility through data analysis. Expert systems use domain expertise to make decisions, although they might not be as flexible as data-driven methods. Hybrid approaches integrate these strategies to improve flexibility and performance. New developments include smart heat exchangers with IoT capabilities for real-time monitoring, compact designs for a variety of applications, and new materials and coatings that improve durability and efficiency. Reducing environmental effect is also reflected in sustainable solutions like waste heat recovery. Nevertheless, issues like computing costs, data quality, and interaction with current systems still need to be resolved. Optimized computational methodologies, modular integration, and sophisticated sensor technology are required to address these problems. AI has the power to completely transform heat exchanger technology by enhancing sustainability and efficiency. Future breakthroughs will be fueled by ongoing improvements in materials, designs, and AI approaches, offering more complex solutions to satisfy changing environmental and performance requirements.

Building energy consumption analysis and measures: a case study from an administration building in Chengdu, China

With the peak of carbon dioxide emissions and carbon neutrality, China is placing greater emphasis on energy expenditure. Office buildings occupy a prominent position in building energy consumption, which is one of the main energy consumption areas. Taking an administration building in Chengdu as an example, this article simulates the building energy consumption based on Design Builder software, examines the variables influencing energy consumption, and suggests energy-saving strategies combined with fresh ideas for sustainable architectural design. The results showed that the modeling building was a high-energy-consuming building, with an energy consumption of 724,857.59 kWh, and a unit area energy consumption of 288.17 kWh/m2 in Chengdu. For energy conservation and emission reduction, this article proposes the following three energy-saving measures. The first is to apply heat recovery technology for air conditioning systems. The second is photovoltaic glass, which provides partial electricity demand for buildings and reduces dependence on traditional energy sources. The third is roof greening, which utilizes the plants to purify the air and beautify the environment. The results showed that the heat recovery technology in air conditioning systems reduced the total energy consumption of buildings from 642144.04 kWh/m2 to 502937.83 kWh/m2, photovoltaic glass reduced 552243.87 kWh/m2, and roof greening reduced to 635947.35 kWh/m2. All of these have good energy-saving and emission reduction effects. The above three strategies not only help reduce building energy consumption, but also provide substantial support for China to achieve carbon neutrality.

Exploration of new function for thermal energy storage: Temperature stabilizer

Thermal energy storage (TES) is a technology that stores thermal energy by heating or cooling a storage medium so that the stored energy can be used when needed. TES is usually used in greenhouse heating, centralized solar power, and industrial waste heat recovery to improve the efficiency of energy utilization. This article explores a new application of TES, which relies on its constant outlet temperature to provide stable working conditions for other components. A simulation consisting of 10 cycles with a total length of 100 h is designed. Each cycle contains 5 h of discharge and 5 h of charge, achieved by adjusting the inlet temperature. Rock and NaNO3 are selected as materials for sensible and latent heat storage. This paper discusses the temperature distribution and thermal storage capacity of TES under alternating inlet temperature. The results indicate that the outlet temperature of sensible heat storage will fluctuate and the maximum amplitude is 4.56 K. For latent heat storage, the outlet temperature is constant, and fluid temperature and liquid phase ratio distribution do not change with the number of cycles. There is a significant temperature difference between fluid and solid in phase transition stage, with a maximum value of 10.72 K. Mathematical relationship between latent heat storage parameters and the minimum length of TES is obtained.

Thermoelectric Generator Applications in Buildings: A Review

With growing concerns about building energy consumption, thermoelectric generators (TEGs) have attracted significant attention for their potential to generate clean, green, and sustainable power. This comprehensive review explores the applications of thermoelectric generators (TEGs) in building systems, focusing on recent advancements from 2013 to 2024. The study examines TEG integration in building envelopes, including façades, walls, windows, and roofs, as well as non-integrated applications for waste heat recovery and HVAC systems. Key findings highlight the potential of TEGs in energy harvesting and thermal management, with façade-integrated systems generating up to 100.0 mW/m² and hybrid LCPV/T-TEG systems achieving overall efficiencies of 57.03%. The review also identifies critical parameters affecting TEG performance, such as solar intensity, thermoelectric arm length, and PCM melting temperature. Despite promising results, challenges remain in improving overall system efficiency, cost-effectiveness, and scalability. Future research directions include developing more efficient thermoelectric materials, optimizing system designs for various climatic conditions, and exploring integration with smart building management systems. This review provides valuable insights for researchers and practitioners working towards more energy-efficient and sustainable building designs using TEG technology.

Flow-induced vibration of turbo-expander impellers for industrial waste heat recovery: An analysis based on two-way fluid structure interaction

In the effort to conserve energy and reduce emissions, waste heat recovery for power generation offers a significant advantage by enabling energy recycling. The turbo-expander, a critical component within expansion power generation systems, plays a pivotal role. However, flow during various operation can generate vibrations that negatively affect operational efficiency and trigger safety hazards. Therefore, studying the flow-induced vibration of the turbo-expander is of significant value. We apply computational fluid dynamics (CFD) and transient structural mechanics to examine the flow-induced vibration characteristics of the turbo-expander influenced by stator-rotor interaction using a two-way fluid structure interaction (FSI) strategy. The flow field modeling and calculation approach discussed here is validated through actual operating data from a prototype. Subsequent stages involve coupling the steady-state flow field with the structural field and performing pre-stress modal analysis on the impeller. In the end, we integrate flow-induced excitation from flow field calculations with the transient structural field to calculate the impeller’s flow-induced vibration at the expansion end of the turbo-expander. Our analysis reveals that guide vane frequency (3267 Hz), its harmonic frequencies, and pre-stress modal frequency (1465 Hz) prominently manifest in pressure pulsation and the dynamic response of the turbo-expander impeller under the influence of stator-rotor interaction.

Intelligent energy management and operation efficiency of electric vehicles based on artificial intelligence algorithms and thermal energy optimization

As the global concern for environmental protection and sustainable development intensifies, electric vehicles (EVs), as a representative of clean transportation, are gradually receiving attention. This study aims to explore an intelligent energy management system for electric vehicles based on artificial intelligence algorithms, and focuses on optimizing heat energy utilization to improve the overall operating efficiency of electric vehicles. This paper uses machine learning and deep learning technologies to build intelligent decision-making models, and realizes dynamic optimization of energy demand and heat recovery by analyzing real-time data of electric vehicles under different working conditions. At the same time, a set of thermal management system is designed, which combines the driving state and environmental conditions of the vehicle to optimize the thermal management strategy of the battery and the motor. The experimental results show that the intelligent energy management system based on this research shows good adaptability and stability under different climate conditions, and significantly reduces energy consumption. Therefore, the intelligent energy management system of electric vehicles based on artificial intelligence algorithm and thermal energy optimization effectively improves the operating efficiency of electric vehicles.

Alkali alkanoate ionic liquids for thermal energy storage at mid-to-high temperature: Synthesis and thermal–physical characterization

Thermal energy storage is gaining much attention and experiencing a renascence in last years. In this sense, storing thermal energy in form of latent heat is of special interest due higher energy density, lower energy losses and higher energy efficiency. To store thermal energy as latent heat the presence of a phase change material (PCM) is needed and its performance the key for its implementation in a thermal energy storage (TES) system and the temperature at which the phase change takes place, low (<150 °C) or high (>150 °C) temperature, will condition the application of a given PCM. In this context, the development of PCM materials to store latent heat at mid-to-high temperature in between 150 °C and 350 °C is of special interest e.g., in the field of concentrated solar power or heat recovery. There are already some solid–liquid phase change materials working in this range of temperature e.g., sugar alcohols, aromatic organic compound, inorganic salts, or blend of inorganic salts but all of them present different drawbacks, such as vapor pressure, degradation, low thermal conductivity, corrosion, etc. In consequence, there is a need to explore new PCM materials in this range of temperature applications. In this context, ionic liquids could play a key role in the development of novel PCMs due to their intrinsic properties. Indeed, ILs are gaining increased attention in the field of thermal energy storage in the last years but mainly in the low temperature range (<150 °C) remaining their application in the mid-to-high temperature range in between 150 °C and 350 °C underestimated. In this work, we prepared six different alkali alkanoate ionic liquids, namely [Na][MeOC2], [K][MeOC2], [Na][MeOC3], [K][MeOC3], [Na][MeOC4] and, [K][MeOC4] by direct reaction between the desired methyl methoxycarboxylate ester with NaOH or KOH. The prepared ionic liquids were structurally characterized, and their thermal–physical properties evaluated. Five of them but [K][MeOC3] showed good enthalpy values ranging from 119 J/g to 197 J/g and four of them [Na][MeOC2], [K][MeOC2], [Na][MeOC4] and, [K][MeOC4] have showed excellent thermal stability above 380 °C. In addition, these four ionic liquids have successfully passed the cyclability test showing no significant enthalpy losses (between 0 % minimum and 7 % maximum) after 50 heating/cooling cycles compiling with the cycling category F of the RAL-GZ 896 (Quality Association PCM). All in all, these prepared ionic liquids surpass sugar alcohols in terms of cyclability and thermal stability and are comparable with the inorganic salts e.g. NaNO3 employed in the studied range of mid-to-high temperature (150–350 °C).

Coupling a thermoelectric-based heat recovery and hydrogen production unit with a SOFC-powered multi-generation structure; an in-depth economic machine learning-driven analysis

This study presents a comprehensive technical, environmental, and economic analysis of a thermal power plant utilizing solid oxide fuel cells (SOFC) to meet urban demands for electrical power, fresh water, and hydrogen. The integrated system includes SOFC with anode and cathode recycling, multi-effect desalination, a power generation cycle with a heat recovery unit using a thermoelectric generator, and a hydrogen compression unit. A detailed parametric analysis was conducted to identify optimal conditions for key outputs such as total cost rate and exergy efficiency, employing genetic algorithms and artificial neural networks. According to the economic evaluation, the SOFC stack accounts for 65.11 % of total costs at 139.8 $/h, with the inverter contributing 11.9 %. The environmental analysis shows that the proposed system emits the least CO2 per energy unit compared to SOFC/GT and SOFC/GT/RC systems. The parametric study indicates that increasing the pressure ratio enhances the output power of the SOFC and the production of the gas turbine. However, this also leads to higher compressor consumption, thereby reducing net power. Furthermore, increasing the current density results in greater production of electricity, hydrogen, and freshwater, while also raising the exhaust gas temperature, which aids in the desalination process. The optimization results show an exergy efficiency of 61.38 % and a total cost rate of 132.9 $/h, with artificial neural networks reducing optimization time from 124 h to 14 min.

Improving Wastewater Heat Recovery Using Phase Change Material Heat Exchangers: A Numerical Study of Thermal Performance

ABSTRACTIndustrial processes often generate substantial amounts of wastewater with significant thermal energy content, which is typically discarded as waste. A promising approach to increase energy efficiency and advance sustainable resource management is waste water heat recovery. Utilizing a phase change material (PCM) to extract waste heat from wastewater and transfer it to cold water is an innovative method that separates the demand and supply of heat, while also integrating storage and transmission within a single heat exchanger (HE). A 3D numerical model of PCM‐based HE is developed and simulated. The thermal behavior of PCM and preheating of cold water are investigated in this study. In order to increase the thermal conductivity of the PCM, fins are strategically positioned. Around 71.13% of melting time is reduced by adding fins. Further, the 10° orientation of the fins is also numerically observed and it is found that it helps to improve natural circulation of molten PCM. Thus, melting time is reduced by 34% compared to the vertical fin. A 3.5°C–4.5°C temperature rise in cold water is obtained with the inclined fin, which is 14.28% higher than the vertical fin model.

An experimental study on the wettability of nanofluids

The wettability of nanofluid is a key factor affecting oil recovery and fluid heat transfer. However, the traditional wettability measurement method consisting in determining the contact angle enables to assess the wettability at a solid–liquid contact point only and not within the continuous detection range. Therefore, in this work, a lateral friction detection system is used to continuously measure the wettability of hydroxylated multi-walled carbon nanotubes/deionized water (MWCNT-OH/DIW) nanofluids on polydimethylsiloxane surfaces. Specifically, MWCNT-OH/DIW nanofluids with various mass fractions are configured, and different surfactants are introduced to regulate the dispersion in deionized water. The results reveal that the surface tension and contact angle decrease simultaneously with the increase in MWCNT-OH/DIW mass fraction. Meanwhile, this change also causes an increase in the lateral friction at the nanofluid/PDMS interface. Furthermore, both sodium dodecyl sulfate and cetyltrimethylammonium bromide (CTAB) as surfactants can effectively reduce its surface tension. Notably, when CTAB is added, the maximum static friction (132.62 μN) exceeds that of SDS (113.13 μN). Therefore, the proposed method opens up new prospects in wettability detection of nanofluids.

Thermodynamic analysis of heat pump heating system based on flue gas waste heat recovery

Abstract A lot of waste heat has not been recycled from exhaust gas of gas-fired condensing boilers. By enhancing boiler’s thermal efficiency, condensation latent and heat sensible heat should be deeply utilized. This article uses a heat pump to recover the waste heat from boiler flue gas to improve the heating efficiency of the unit. Taking an example of boiler unit, to illustrate the function of the thermodynamic capability, this article create a new heating system by installing a flue gas condenser and a low-temperature economizer, and a thermodynamic model. The experimental results show that if gas is cooling from 130°C to90°C and coefficient of performance(Cop ) is set by 1.746, by setting a low-temperature economizer, 20.87MW can be obtained from waste heat, which decrease water consumption of desulfurization tower 28.792t / h; due to that the heat pump use the condenser, waste heat can be recovered to 10.10MW and condensed water can be recovered to13.654t / h. When heat network’s return water increases, Cop decreases, but efficiency will increases in network; when outlet water in condenser increases, Cop and network efficiency decrease, but heat pump system increases in efficiency.

Design, optimisation and evaluation of the S-CO2 Brayton cycle for marine low-speed engine flue gas

Five configurations of the S-CO2 Brayton cycle (SCBC) were constructed for flue gas waste heat recovery (WHR) of the marine low-speed engine HHM-6EX340EF on the EBSILON platform using the bench test data to save energy, reduce emissions and the efficient operation of ocean-going vessels. Experimental data from Sandia National Laboratories (SNL) was utilised to validate the accuracy of the model and the effect of Brayton cycle parameters on flue gas WHR for different configurations was analysed. The parameters of the SCRBC (S-CO2 recompression Brayton cycle) were optimised by combining the Neural Network Fitting (NNF) model, Multi-objective optimisation algorithms, and multi-criteria decision-making methods. Finally, the thermodynamic analysis of the low-speed engine was comprehensively evaluated by comparing five configurations of SCSBC (S-CO2 simple Brayton cycle), SCCBC (S-CO2 recuperative Brayton cycle), SCHBC (S-CO2 reheating Brayton cycle), SCIBC (S-CO2 intercooling Brayton cycle), and SCRBC. The optimised SCIBC configuration had the highest net recuperated work of 195.76 kW and the highest Brayton cycle efficiency of 20.13 %. The engine efficiency was improved by 0.82 %, 1.45 %, 1.78 %, 1.86 % and 1.68 %, the BSFC was decreased by 3.20 g/kW·h, 5.56 g/kW·h, 6.82 g/kW·h, 7.04 g/kW·h, and 6.43 g/kW·h, and the output power increased by 86.90 kW, 153.33 kW, 195.76 kW, 189.36 kW, and 178.14 kW, respectively. The maximum exergy loss of the cooler was 162.67 kW with an exergy loss efficiency of 14.54 % in the SCSBC configuration. Optimising the flue gas heat exchanger and cooler will further enhance the efficiency and reduce emissions. Research on the parameter and configuration optimisation of the SCBC for marine low-speed diesel engines can be extended to other low-speed engines.

Thermodynamic analysis of the air separation unit and CO2 purification unit in the semi-closed supercritical CO2 cycle with nearly zero emission

The natural gas-fired semi-closed supercritical CO2 cycle is an efficient oxyfuel combustion power generation technology featuring nearly zero emissions. This study investigated the interaction of the semi-closed supercritical CO2 power unit with the air separation unit (ASU), which supplies O2 for combustion and adiabatic compression heat for the heat recovery process in the power unit, and the CO2 purification unit (CPU), which refines the CO2 in the exhaust gas to 99.97% for enhanced oil recovery (EOR) applications. The detailed thermodynamic models of the power unit, ASU, and CPU have been constructed to explore the impact of variations in oxygen purity and excess oxygen coefficient on the overall thermodynamic performance of the system. The results demonstrate that the net electric efficiency peaks at an oxygen purity of 98%, and a one percent decrease in oxygen purity reduces the net electrical efficiency by approximately 0.36% to 0.97% points. Moreover, the net electric efficiency decreased by 0.10% points when the excess oxygen coefficient increased from 3.00% to 13.67%. These findings may offer valuable guidance for developing oxyfuel combustion power generation technologies.

Performance analysis and additive screening of a liquid carbon dioxide mixture energy storage system coupled with a coal-fired power plant

Liquid carbon dioxide (CO2) energy storage is a promising technology for balancing grid supply and demand, but liquefaction in high temperature environments is a substantial dilemma. In this study, a novel liquid CO2 mixture energy storage system coupled with a coal-fired power plant is proposed to broaden the liquefiable ambient temperature range, where condensate and feedwater without phase change are used for compression heat recovery and CO2 mixture heating. Firstly, eight refrigerant additives are selected to blend with CO2; then, comparative performance analysis between CO2 mixtures and pure CO2 is conducted, followed by parametric studies; finally, a double-layer decision-making framework based on multi-objective optimization is adopted for additive screening across various ambient temperatures. The results show that a moderate amount of additive favors system safety but degrades thermodynamics and economy, well at high temperatures the performance of CO2 mixture improves and absolutely outperforms pure CO2. CO2/difluoromethane (CO2/R32) reduces the system operating pressure by 20.95 % over pure CO2 at ambient temperature of 298.15 K, accompanied by only 5.78 %, 0.76 % and 9.92 % deterioration in round-trip efficiency, energy storage density and levelized cost of electricity, and exhibits optimal adaptation to varying additive mass fraction. The working fluid unit cost and heat exchangers are the main factors causing these variances. In response to environmental changes, CO2/propylene (CO2/R1270) and CO2/R32 emerge as the two most adaptable mixtures, with the former preferred at low ambient temperatures (288.15–293.15 K) and the latter at high ambient temperatures (298.15–308.15 K). Among all additives, R600 and R161 consistently rank lowest in priority regardless of ambient temperature.

Performance and optimization evaluation for integration of sCO2 power system into the aircraft propulsion system

The aviation industry accounts for part of the CO2 emissions contributing to climate change. The industry has established a target to reduce 2050 net aviation carbon emissions by 50 % relative to 2005 levels. With this in mind, waste heat recovery is a key pathway to achieve reduced emissions and improve system efficiency. The waste heat may potentially be converted to electric power using a supercritical CO2 Brayton power cycle. The sCO2 power system offers the advantage of compactness owing to the high working fluid density, which is an important consideration for aircraft performance. The present work focuses on the integration of the sCO2 power system into the aircraft propulsion system and evaluation of its performance. Detailed optimization of the sCO2 waste heat system will be evaluated with a focus on cycle efficiency and net power under different operating conditions, including ground, takeoff, climb, cruise, and landing operations. The study is divided into two parts with two different turbofan engines, one with a nominal thrust of 30 kN and the other with a nominal thrust of 9 kN. The first part shows the effect and operation of the waste heat recovery unit under the different operating conditions. The second part is focused on cycle optimization and performance evaluation. The results demonstrate the potential of waste heat recovery during a range of operational conditions. The sCO2 cycle efficiency can reach between 25 and 39 % (depending on aircraft engine) with net power output in the range of 100 to 260 kW.

Experimental investigation of a small-scale reversible high-temperature heat pump − organic Rankine cycle system for industrial waste heat recovery

Innovative technologies are required to mitigate the challenges of climate change. A reversible high-temperature heat pump (HTHP) − organic Rankine cycle (ORC) system can be used for effective utilisation of industrial waste heat in the lower temperature band <100 °C. The system can provide useful process heat for industrial processes by operating in HTHP mode or generating power in ORC mode. This paper presents the experimental investigation of the reversible system in both HTHP and ORC modes. A single scroll unit was selected for the compressor (HTHP) and expander (ORC) roles, keeping the system compact. A HCFO refrigerant, R1233zd(E), with a low GWP value, was chosen as the working fluid for both operating modes. When operated in HTHP mode, a maximum compressor overall isentropic efficiency of 73.4 % and a COPmech of 4.8 (ΔTlift,rside = 41 K, Tsf,ev,in = 60 °C) was obtained. In ORC mode, the maximum net power output was 512.4 W (Tsf,ev,in = 90 °C, rp = 2.3), overall cycle efficiency was 3.01 %, and overall isentropic efficiency of the expander was 54.6 %. The technical limitations encountered, and solutions put in place during the experimental testing campaign are discussed in detail.

Waste heat utilisation during moulding sand reclamation process

The paper presents research to develop a complete system for recovering, storing and utilising the thermal energy of the knocked-out moulding sand. The cooling of the moulding sand is slow and, therefore, moulding sand cannot be used in a regeneration station and returned to the foundry process quickly. The moulding sand cooling process can be accelerated, and the recovered heat can be used in other energy-intensive processes in the foundry. As for now, the heat recovery methods or the ways of the heat further use are unknown. This paper presents the concept of a heat recovery system that allows to utilise the heat contained in moulding sand knocked out of large moulds at temperatures between 350 and 400 °C. The permissible moulding sand temperature at the inlet to the regeneration station should not exceed 90 °C. It is assumed that the moulding sand will be cooled with water in two vertical cylindrical tanks where heat exchangers with finned tubes will be placed. Using numerical modelling, the design of a heat exchanger for moulding sand cooling was selected. The capacity of the developed heat exchanger is 600 kW. Numerical analyses and experimental tests confirmed that the heat exchanger can absorb all the heat from the moulding compound and cool it down to 90 °C within 6 h. Implementing the developed system will reduce the foundry's CO2 emissions by 329 tonnes annually.

Radiative heat recuperation in combustion of layered solid fuel

In this work, we investigate the properties and stability of the combustion waves propagating in a system of layered solid fuel material in which the neighbouring fuel sheets can recuperate heat via thermal electromagnetic radiation. The analysis is undertaken within the flame sheet model, which allows to determine the combustion wave speed and structure and derive the dispersion relation characterising the stability of the reaction front. The proper choice of parameters leads to superadiabatic combustion temperature and significant increase of the combustion wave speed. In addition, the stable steady regimes of combustion can be substantially extended in the space of parameters. Such an enhancement of stability and ability to control the characteristics of the combustion wave propagation can be very attractive for the combustion synthesis of new layered materials, similarly to the chemical furnace technology proposed earlier.

Operational strategies and well design for reservoir thermal energy storage (RTES)

The intermittency of renewable energy sources necessitates effective energy storage solutions. This study narrows in on reservoir thermal energy storage (RTES) as a system to bridge the supply–demand gap through the storage and recovery of heated water for periods ranging from daily to monthly timescales. By injecting hot water into subsurface formations and later retrieving it for use in electricity generation or direct heating, the viability of RTES is explored for load-levelling applications, typically on daily to monthly timescales rather than extended seasonal or multi-year storage. Many factors including formation parameters (e.g. permeability, porosity, thermal conductivity of rock, thickness and insulating layers), completion parameters such as injection well design, operational parameters such as injection and production rates, and schedule affect the facility's performance. The two key performance indicators (KPI) considered herein are the produced water temperature and the heat recovery factor. In this study, three operational strategies and four different well completions were investigated using a coupled fluid–thermal simulation model. Heat loss from the upper and lower boundaries of the reservoir was also studied. While the immediate impact of initial hydro-thermal charging on produced water temperature may not persist in the long-term operation, it does influence the overall system efficiency by reducing the cumulative heat recovery. Through detailed analysis, it is demonstrated that vertical injection across the entire well length offers a balanced approach between minimizing pumping costs and maximizing heat extraction efficiency. This study establishes basic calculations for developing innovative operational and completion strategies to maximize the long-term economic benefit of RTES.