kW Of Heat Research Articles

Energy and exergy analysis of a new solar hybrid system for hydrogen, power and superheated steam production

This study investigates the amalgamation of solar tower technology and thermal energy storage (TES) within the framework of a supercritical carbon dioxide (S-CO2) Brayton cycle, a copper-chlorine (Cu-Cl) hydrogen production cycle, and a heat recovery steam generator (HRSG) to generate superheated steam. The various subsystems have been merged to enhance overall energy efficiency significantly, ensure uninterrupted operation, and minimize exergy loss. Energy and exergy analyses have been carried out to assess the prerequisites and effectiveness of each subsystem, highlighting the thermodynamic benefits of integration. Engineering Equation Solving Software (EES) was employed to solve the integrated system model and assess the thermodynamic properties provided by the EES library. Results showed that in the basic design mode, exergy destruction in the solar tower, S-CO2 Brayton cycle, and Cu-Cl cycle are 9930 kW, 7111 kW, and 9735 kW, respectively. The system produces 4226 kW of power, 2697 kW of heat, and 0.04971 kg/s of hydrogen. The overall energy and exergy efficiency of the power plant are 17.48 % and 18.72 %, respectively. These findings demonstrate that this integrated system can address key gaps in the literature by presenting a novel combination of solar power-driven Cu-Cl hydrogen production and superheated steam generation. The proposed system contributes to advancing renewable, efficient, and uninterrupted energy production.

Design and analysis of thermoacoustic air source heat pump water heaters

Thermoacoustic air-to-water air source heat pumps (TAWASHP) are the eco-friendly, simple, compressor less, low cost and likely looking future substitute for the existing compressor-based heat pumps. In this work, the design optimization of the 1-kW TAWASHP with helium for the temperature difference of 15 to 70 K for pumping heat from the atmospheric air to water using the linear thermoacoustic concepts was discussed. The optimized design can fit for both cooling and water heating applications without wasting the heat rejection to the surrounding atmosphere, rather supplied to the insulated hot water tank. The optimized one-fourth wavelength resonator TAWASHP shows the coefficient of performance of 1.1 to 2.34. The theoretical results are validated with the DeltaEC software results, and the results are in concurrence with each other. The DeltaEC predicts the TAWASHP can supply 1.55 to 3.35 kW of heat to water, which is equivalent to 37.3 to 80.3 kWh of heat energy per day.

Comprehensive evaluation of a new integrated ORC-VCR system with a thermoelectric generator unit combining sustainable energies for hydrogen production

Recently, there has been a growing emphasis on the efficient generation of energy from sustainable sources. This study aims to evaluate a new combined Organic Rankine Cycle-Vapor Compression Refrigeration (ORC-VCR) system from energy, exergy, economics, and environmental perspectives. The system has been designed to cogenerate power, heat, cooling, and hydrogen using solar and biomass energy. To enhance efficiency, a Thermoelectric Generator (TEG) unit has been integrated into the system. The power produced by the TEG is used to generate hydrogen in the Proton Exchange Membrane Electrolyser (PEME). To ensure the continuous operation of the solar collector, especially under conditions of unstable and intermittent solar radiation, a thermal storage tank and a biomass-fired boiler utilizing four different types of biomass (wood, paper, municipal solid waste, and sawdust) have been incorporated. The primary objective of this research is to investigate the impact of employing various biomass types on the system's performance. The results indicate that in terms of energy and exergy, municipal solid waste yields the highest system efficiency. However, from an environmental viewpoint, paper incurs lower pollutant emissions. The proposed hybrid system can produce 145.5 kW of cooling, 513.6 kW of heat, 37.93 kW of electricity, and 0.756 kg/h hydrogen with energy and exergy efficiencies of 32.73% and 14.18%, respectively. The estimated total equipment cost is 7.67$/h, with a CO2 emission of 0.0029 kg/s.

Performance analysis of compression-assisted absorption refrigeration-heating system for waste heat recovery of liquid-cooling data center

The power consumption for cooling of data centers increases continuously contributed to the enlargement of heat dissipation demands. Waste heat recovery is regarded as a promising solution for energy conservation and carbon reduction. A compression-assisted absorption refrigeration-heating system aimed at waste heat utilization of liquid-cooling data center is proposed. The effects of heat sources, auxiliary compression process and split ratios on the proposed system performance are discussed, and the analysis of application that synchronously produces chilled water for liquid-cooling data center and hot water for domestic use is conducted. The compression process can provide effective compensation for the system performance that weakens the demands on the quality of cooling source and driving heat source. As the compression ratio raises from 1.067 to 2.0, the minimum generation temperature decreases from 52.0 °C to 27.2 °C. The system can completely satisfy the refrigeration need, of 4.29 kW for liquid-cooling data centers and provide additional thermal energy, of 1.37 kW for heating. A quantitative relationship between the flow split ratios and circulation ratios is found out that can be a wise presentation for the adjustment of the refrigeration and heating loads. This research results can provide theoretical basis and guidance for low-grade waste heat recovery in liquid-cooling data center based on the absorption heat pump technology.

Thermodynamic analysis and multi-objective optimization of an ORC-based solar-natural gas driven trigeneration system for a residential area

Regarding the growing demands for energy, depletion of fossil fuel resources, and the adverse environmental consequences associated with their utilization, especially global warming, it is imperative to increase the share of renewable resources within energy systems. During the summer season, the residential sector in Khuzestan province, Iran, experiences a significant surge in energy consumption. This elevated demand is mostly attributed to the region's severe temperatures, requiring the extensive use of cooling equipment. As a result, taking into account the high potential for solar energy in the nation, this research first uses TRNSYS software to calculate the cooling and heating loads of a residential area in the province of Khuzestan. Next, a solar-natural gas Combined Cooling, Heating and Power (CCHP) system is designed and modeled using Engineering Equation Solver (EES) software, with the goal of supplying the cooling load. Then, using the particle swarm optimization technique, the system's multi-objective optimization was completed. The results showed that a fuel consumption rate of 0.04274 kg/s is required in steady state conditions to supply a cooling load of 1446.2 kW for the region with 1000 m2 of solar collecting area. A total of 465.7 kW of electric power and 3336 kW of heating are produced. The system's energy and exergy efficiencies were determined to be 186.6 % and 27.81 %, respectively. Eventually, the findings of this study demonstrated that the proposed configuration has the potential to provide multiple positive outcomes with a high level of efficiency, and improve the share of renewable energy.

Performance evaluation of a novel fuel cell and wind-powered multigeneration system

The introduction of promising energy sources to satisfy human desires is extremely crucial. The present work studies the performance of an original solid oxide fuel cell-wind-based polygeneration system for producing hydrogen, sodium hypochlorite, potable water, heating, cooling, and electrical power. In the methodological concept, energy, exergy, economic, and exergoenvironmental assessments are carried out to evaluate the system performance concerning different parameters. The technical outcomes depict that the system can produce 363 kW of electrical power, 162 kW of cooling, and 46.5 kW of heating at the design operating settings while the energy and exergy efficiencies are 55.5% and 38.1%, respectively. Moreover, over a year of operation, the system can provide 19.9 × 10 4 m3 gaseous hydrogen, 50.9 ×‎ 103 m3 potable water, and 5.31 tonnes of sodium hypochlorite to increase the gained benefits from this efficient and cost-effective system. To evaluate the prevalence of the designed system, the economic outcomes demonstrate that the payback period is 1.5 years while the internal rate of return is 0.70. Moreover, the system presents relatively proper environmental benefits based on the obtained outcomes from the exergoenvironmental study; the exergoenvironmental factor, exergy stability factor, and sustainability index are 0.50, 0.56, and 1.6, respectively.

Assessment of a combined heating and power system based on compressed air energy storage and reversible solid oxide cell: Energy, exergy, and exergoeconomic evaluation

The electricity grid with high-penetration renewable energy sources has urged us to seek means to solve the mismatching between electricity supply and demand. Energy storage technology could accomplish the energy conversion process between different periods to achieve the efficient and stable utilization of renewable energy sources. In this paper, a hybrid energy storage system based on compressed air energy storage and reversible solid oxidation fuel cell (rSOC) is proposed. During the charging process, the rSOC operates in electrolysis cell (EC) mode to achieve the energy storage by converting the compression heat to chemical fuels. During the discharging process, the cell operates in fuel cell mode for electricity production and the gas turbine is conducted to recover the waste heat from cell. To evaluate the comprehensive performance of the proposed system, the energy, exergy, and exergoeconomic studies are conducted in this paper. Under the design condition, the results indicated that the proposed system is capable of generating 300.36 kW of electricity and 106.28 kW of heating; in the meantime, the energy efficiency, exergy efficiency, and total cost per unit exergy of product are 73.80%, 55.70%, and 216.78 $/MWh, respectively. The parametric analysis indicates that the increase in pressure ratio of air compressor, steam utilization factor of rSOC stack under EC mode and current density of the rSOC stack under EC mode reduce exergy efficiency and total cost per unit exergy of product simultaneously, while the increment of operating pressure of rSOC stack under FC mode enhances the exergy efficiency and decreases total cost per unit exergy of product. The multi-objective optimization is carried out to improve the comprehensive performance of the proposed system, and the results expressed that the best optimal solution has the exergy efficiency and total cost per unit exergy of product of 65.85% and 187.05 $/MWh, respectively. Compared to the basic operating condition, the improvement of the proposed system has led to the maximum enhancement of 20.32% in exergy efficiency and 18.60% in total cost per unit exergy of product.

Study on various hot-gas defrosting configurations for CO2-NH3 cascade deep freezer

Four hot-gas bypass defrosting configurations for CO2-NH3 cascade blast freezer for application in fish processing firm are numerically investigated. Due to the high moisture content of fish, defrosting is necessary after every 4 to 5 h of batch operation. A thermodynamic model for the cascade system and defrosting was developed to study various defrosting configurations formulated by rearranging the existing compressor to operate as a defrosting compressor and with the addition of an external defrosting compressor. From the simulation findings, it can be summarized that the conventional hot-gas bypass defrosting without defrost compressor is suitable for a high-capacity cascade refrigeration system with more than three evaporators. For low cooling capacity refrigeration systems, a defrosting compressor is necessary to elevate the temperature above the cascade condensing temperature. A dedicated defrosting compressor with a power consumption of 3.1 kW and a modified refrigeration/defrosting compressor with a power consumption of 6.8 kW can deliver 33.3 kW of heating at a temperature of +10 °C (45 bar). Incorporating a desuperheater between the main and defrosting compressors reduces compressor temperature and maintains the lubricating oil stability, without change in defrosting energy consumption and less exergy loss. The defrosting efficiency is obtained in the range of 39.7–42% which is in agreement with published literature.

A special-shaped sodium heat pipe with a “bridge-type” artery for coupling free-piston Stirling generator and fission reactor

The nuclear-powered free-piston Stirling generator (FPSG) by using heat pipes as heat transfer devices has significant potential for future applications in the deep space exploration. Due to the compact size of the FPSG, it is very difficult to directly insert the cylindrical heat pipe into the heat head to transfer heat, which has been a challenge for application in such a system. Here, a special-shaped heat pipe is designed to match the heat head. In this design, the surface of the heat head was used as the condensing surface and a “bridge-type” composite artery was used to transfer the liquid sodium from the condensing surface to the evaporating surface, which could greatly simplify the structure and improve the capillary limit. A simplified model for arterial wick was proposed to predict the artery geometrical parameters and capillary limit and the performance of the startup and steady state were experimentally investigated. It successfully transmitted about 4 kW of heat with a tilt angle of −35°, verifying the feasibility of the new structure. The effect of different cooling conditions and inclinations were also investigated. To ensure that the heat pipe was fully activated, it was necessary to meet the minimum input power under different cooling conditions.

An innovative process design and multi-criteria study/optimization of a biomass digestion-supercritical carbon dioxide scenario toward boosting a geothermal-driven cogeneration system for power and heat

In the pursuit of enhancing both sustainability and energy density in low-temperature, renewable energy-based cycles, the integration of high-temperature renewable streams is considered a key objective in multigenerational scenarios that focus on renewable energy. This integration is recognized for its ability to reduce irreversibility and facilitate the development of eco-friendly designs. Consequently, the development, analysis, and optimization of an innovative multigenerational system, which utilizes a combination of biomass feedstock and geothermal energy resources, are the aims of this study. In this system, the performance of a geothermal-driven subsystem is significantly enhanced by a biomass-fueled subsystem, contributing to a more efficient overall system. This enhancement involves the integration of biomass digestion with a supercritical CO2 process. The energetic flue gas generated in this process is then utilized to enhance the enthalpy level of geothermal water through a dual-flash process. This process includes an advanced Kalina cycle, enabling combined cooling, heating, and power generation. The feasibility of this structure is examined through a comprehensive analysis that encompasses thermodynamic and economic considerations. The performance optimization is targeted using the Multi-Objective Grey Wolf Optimization technique, and within this framework, two multi-criteria optimization scenarios are defined based on power and heat output, exergy efficiency, and the system's profitability. Furthermore, a detailed sensitivity analysis is conducted, where the impact of variations in five key decision parameters is evaluated. It is indicated by the results that 500.8 kW of power, 900.2 kW of heating, and 4.931 kW of cooling can be provided by the system, which also achieves an exergetic efficiency of 23.08 % and a payback period of 6.87 years.

Comparative analysis of a multi-generation system using different conventional & nano based working fuels

The present study focuses on the energy and exergy analyses of a multi-generation system that uses both non-renewable and renewable energy sources, fulfilling the energy requirements of a community in a sustainable manner. The operational comparison of the proposed system with both conventional and non-conventional nano-based working fuels is also studied. The proposed system provides a total of six outputs which include electricity, desalinated water, space heating, space cooling, hot water, and waste heat for industrial purposes. The effects of variation in geothermal fluid’s mass flow rate, pressure, and quality on system outputs are evaluated. System performance with different fuels having varied calorific values is evaluated and it is found that the fuels with the highest calorific values provide the best possible system outputs. The outputs of the system at a specific working condition are 6.7 MW of electricity, 650 kW of waste heat, 10.54 kg/s of desalinated water, 41 kg/s of hot water, 331.7 kW of heating and 314.1 kW of cooling.

Integration of a Gamma-Type Stirling Engine with LPG Cooking Stove for Micro-Scale Combined Heat and Power Generation

The Stirling engine is one of the most versatile micro-scale prime movers for combined heat and power applications, adaptable to different levels of heat sources. This study started a unique journey that included developing, experimenting, and analyzing the Gamma-type Stirling engine. Notably, the engine design ingeniously harnesses heat from a customized cooking stove burner powered by liquefied petroleum gas. The engine fabrication resulted in a compression ratio 2.014, accommodating a volumetric capacity of 181 cc. The Stirling engine test used air as the working gas, and the initial conditions were at atmospheric pressure. Stirling engine performance was analyzed using an ideal thermodynamic cycle model and burner efficiency using the water boiling method. The modified burner attains an average temperature of 699.5°C, producing a burner power output of 5.702 kW and a thermal efficiency of 32.7% or around 1.867 kW of heat for operating the engine and cooking activities. Simultaneously, tests of the Stirling engine revealed an average air temperature difference of 146.2°C between the expansion and compression phases. The flywheel rotation speed ranges from 158 to 369 rpm. During testing, the Stirling engine obtained an average thermal efficiency of 31.08%, accompanied by an ideal power spectrum ranging from 0.3 W to 42.6 W. The highlight of this study was the maximum pressure achieved at the end of the heat absorption stage, recorded at 296.1 kPa. Importantly, these findings underscore the promising potential of micro-Combined Heat and Power systems. Integrating the gamma-type Stirling engine with the LPG stove represents novelty and paves the way for further development and advancement in sustainable energy solutions.

Thermodynamics modelling and optimisation of a biogas fueled decentralised poly-generation system using machine learning techniques

In the forthcoming era of smart energy systems, decentralised solutions are gaining increasing prominence due to their superior adaptability for interconnecting sectors, reduced inefficiencies, and environmentally friendly operation. This study introduces a new medium-scale biogas-based power plant that utilises a gas turbine to meet the energy needs of a specific locality, encompassing electricity, heating, cooling, and water supply, all whilst considering the system's environmental impact. To optimise the plant's performance, three different multi-objective optimisation scenarios employing machine learning methodologies and Greywolf algorithms with distinct objective functions are analysed. Under the base conditions, the proposed plant showcases impressive capabilities, delivering 1372 kW of electricity, 246.2 kW of heating, 293.3 kW of cooling, and 4.1 kg/s of distilled water. It operates with first and second law thermodynamics efficiencies of 72.3 % and 41.4 %, respectively, while maintaining a CO2 emission index of 0.778 kgCO2/kWh. Furthermore, the net present value and investment return period for the investment are estimated to be approximately 4.4 million USD and 4 years, respectively. Through optimisation (scenario 1) that prioritises maximising efficiency while minimising product costs and environmental impact, the following parameters are achieved: an exergy efficiency of 42.7 %, a cost of products at 28.8 $/GJ, and a reduced CO2 emission index of 0.762 kgCO2/kWh. The results reveal that the proposed system not only excels in efficiency but also proves to be economically viable and environmentally beneficial.

Performance of a BAPVT modules coupled TEHR unit fresh air system based on micro heat pipe array

Energy consumption for heating and cooling fresh air has become a major component of building energy consumption, and there is a growing focus on highly-efficient and energy-conserving fresh-air treatment technology. This paper presents a new fresh-air system based on a high-efficiency heat transfer element, the micro heat pipe array (MHPA). It consists of a novel air-cooled building attached to a photovoltaic/thermal module (MHPA-BAPVT) and a thermoelectric heat recovery unit (MHPA-TEHR). The system uses solar energy, photovoltaic power generation, and waste heat for fresh air preheating. A series of fresh-air systems were designed, constructed, tested, and analyzed. The results reveal that on sunny winter days, the temperature of fresh air flowing through MHPA-BAPVT modules can increase by 22.15 °C. The average thermal and electric efficiency of the MHPA-BAPVT modules was 12.16% and 7.10%, respectively, and MHPA-TEHR could exceed the upper limit of passive heat recovery technology, which could generate 1.25 kW of heat per 1 kW of input electric power. The maximum ratio of total heating power to the total power consumption of the fresh-air system reached 14.94. During a typical day in the winter season, solar preheating exceeded the fresh air heat requirement by 24.34%, and the excess heat provided 292.92 MJ for building heating demand. Comparing the electric heating fresh-air unit with conventional heat recovery, the former achieved nearly zero energy consumption during the winter season. During the transitional season, the system could provide 711.82 MJ of solar energy, which improved the indoor temperature. Finally, using the experimental data and meteorological parameters of Zibo, the annual heat and electricity benefits and reduced carbon dioxide emissions of the fresh-air system were calculated. The fresh-air system in this study can fully utilize solar energy for heat collection and power generation to reduce building energy consumption and can be applied widely.

Development and assessment of a thermochemical cycle and SOFC-based hydrogen energy system as a potential energy solution for the peak demand in a sustainable community

In this study, an integrated energy system is presented in which hydrogen is produced via the thermochemical cycle. The presented system would provide a potential solution for storing excess electric power in terms of hydrogen generation for a sustainable community. Principles of exergy and energy are utilized to analyze the presented system in terms of exergy and energy efficiencies. The simulation result shows that with the help of the developed system, 0.36 kg/h of hydrogen can be generated, which is utilized via SOFCs to produce and electrify the houses. Additionally, 1000 kW of electric power with 3.6 kW of heating can be supplied via the developed system. With the use of thermochemical cycle considered in the present study, one can produce hydrogen with an energy efficiency of 79.6% and exergy efficiency of 62.9%. Furthermore, to see the impact of different factors on the operation of the developed system, a parametric study is also conducted by changing factors like solar irradiation, the inlet temperature of the molten salt, and the outlet temperature of the solar collector.

Exergy-economic analysis and multi-objective optimization of a multi-generation system based on efficient waste heat recovery of combined wind turbine and compressed CO2 energy storage system

Due to the intermittent feature of renewable energies, their combination with energy storage systems seems efficient and profitable. In this regard, a wind turbine system is coupled with a compressed CO2 energy storage (CCES) system for multi-generation propose. This combination has not been done yet and seems very attractive and efficient with the present popularity of wind energy and energy storage systems. A fraction of the output power of the wind turbine is sent to the compressor and electric heater of the CCES layout in the charging and discharging period. In the CCES system, a thermoelectric generator (TEG 1), an absorption chiller, and a domestic hot water heat exchanger are used to waste energy elimination and the waste energy of the wind turbine is recovered by a trilateral cycle (TLC). The produced power of the TEG 1 and TLC is transmitted to a reverse osmosis desalination unit and an alkaline electrolyzer for freshwater and hydrogen production. Hence, the considered system is converted to a multi-product one. Energy, exergy, and exergy-economic (3E) studies are done on the whole layout through parametric analysis and multi-objective optimization. Exergy round trip efficiency and unit cost of products are obtained as 37.027% and 30.41 $/GJ in the optimization process. The considered system can produce 1960 kW of power, 336.1 kW of heating, 183.3 kW of cooling, 1.077 kg/s of freshwater, and 0.0138 kg/h of hydrogen in this case.

Multi-aspect optimization of a geothermal-based integrated Kalina-proton exchange membrane fuel cell with ejector cooling and desalination systems

In order to use geothermal energy efficiently, a novel poly-generation system is introduced in the present study. In this configuration, the topping system is comprised of the combined modified Kalina cycle and proton exchange membrane fuel cell for power generation. Moreover, the bottoming configuration is composed of an ejector cooling system and a humidification-dehumidification desalination unit for cooling and freshwater production. Furthermore, the output heating is get from the heat rejection stage in the Kalina cycle. The proposed system is examined from energy, exergy, and exergy-economic perspectives through parametric analysis and multi-objective optimization. The effect of changes in geothermal water temperature, the upper pressure of the Kalina cycle, the flash temperature of the Kalina cycle, the outlet temperature of the fuel cell, and the current density of the fuel cell are assessed on the output parameters. Considering exergy efficiency and payback period as the target functions, they are calculated as 43.94 % and 0.859 years. In this case, the considered system can produce 549.1 kW of power, 140.2 kW of cooling, 46.29 kW of heating, and 0.0326 kg/s of freshwater.

Numerical Simulation Study of Geothermal Energy Extraction in Medium-deep Formation

Geothermal energy is a kind of renewable energy with rich content, relatively low cost and wide distribution. China is rich in geothermal reserves and urgently needs efficient heat extraction technology. Closed cycle heat extraction technology is a new geothermal development model that is suitable for medium-deep geothermal reservoir and has high heat exchange efficiency without taking water. In this system, the circulating working fluid is pumped into the annulus from the ground, and the heat is extracted from the formation through heat conduction, and then returned to the ground through the central pipe. In this paper, the heat recovery capacity of the heat extraction system is numerically simulated. The research results show that the coaxial borehole heat exchanger technology has a good heat recovery capacity, and the designed thermal insulation structure has a positive effect on heat extraction and heating, and the heat extraction 100 days can stably produce 360 Kw of heat.

Experimental validation of a solar system based on hybrid photovoltaic-thermal collectors and a reversible heat pump for the energy provision in non-residential buildings

This work aims to validate a transient model of a solar hybrid pilot plant based on photovoltaic-thermal (PV-T) collectors integrated via thermal storage tanks with an air-to-water reversible heat pump (rev-HP). The pilot plant is in operation and provides space heating, cooling, domestic hot water (DHW) and electricity to an industrial building located in Zaragoza (Spain). The plant consists of eight uncovered PV-T collectors (2.6 kWe, 13.6 m2), two water tanks and a rev-HP with a nominal thermal power of 16 kW for heating and 10.5 kW for cooling. The validation results show that the transient model fits the experimental performance of the PV-T collectors, with an average error of -16% and 3%, for the thermal and electrical generation respectively. The accuracy of the estimated rev-HP performance depends on the operation mode. The estimated COP in cooling mode has an average error of 14%, while in heating mode has an average error of -10%. The results show that the integration of the thermal and electrical generation of the PV-T collectors with a high-performance rev-HP allows the solar PV-T system to be self-sufficient to satisfy the building energy demand.

Modelling Interactions between Three Aquifer Thermal Energy Storage (ATES) Systems in Brussels (Belgium)

Shallow open-loop geothermal systems function by creating heat and cold reserves in an aquifer, via doublets of pumping and reinjection wells. Three adjacent buildings in the center of Brussels have adopted this type of aquifer thermal energy storage (ATES) system. Two of them exploit the same aquifer consisting of Cenozoic sands, and started operation in 2014 and 2017, respectively. A previous hydrogeological model developed by Bulté et al. (2021) has shown how the thermal imbalance of one of the systems jeopardizes the thermal state of this upper aquifer. Here, the interactions with a more recent third ATES system located in the deep aquifer of the Palaeozoic bedrock are studied and modelled. After being calibrated on groundwater flow conditions in both aquifers, a 3D hydrogeological model was used to simulate the cumulative effect of the three geothermal installations in the two exploited aquifers. The results of the simulations showed that although the hydraulic interactions between the two aquifers are very weak (as shown by the different observed potentiometric heads), heat exchanges occur between the two aquifers through the aquitard. Fortunately, these heat exchanges are not sufficient to have a significant impact on the efficiency of the individual geothermal systems. Additionally, this study shows clearly that adding a third system in the lower aquifer with a mean power of 286 kW for heating between October and March and an equivalent mean cooling power between April and September is efficient.