Thermoeconomic Analysis Research Articles

A comparative thermoeconomic analysis of fourth generation and fifth generation district heating and cooling networks

The energy refurbishment of residential heating and cooling systems is crucial to achieve the carbon neutrality expected by 2050. In this framework, many researchers are developing low-temperature district heating and cooling systems, integrated with renewable technologies. In particular, fourth-generation district heating and cooling systems are largely used, and a considerable number of these systems have been installed in the last few years. This is due to the wide use of heat pumps and low-temperature heating terminals, such as radiant floors and fan coils. Fifth generation district heating and cooling systems include several significant advancements with respect to the previous technology. This research proposes a thermoeconomic comparison between fourth generation and fifth generation district heating cooling networks, including ground-source heat pumps, supplying heating and cooling energy to a residential district located in Leganes, Madrid. The thermal load of the residential district network is simulated by means of detailed models of the buildings. In the proposed systems, the electric load is partially met by a 3 MW photovoltaic field. The dynamic simulation model of such districts is developed in TRNSYS18, including detailed models for each component. Both the analysed technologies achieve very promising results from both economic and energy points of view. The Primary Energy Saving for the 4th and 5th generation districts are equal to 97% and 81%, respectively. Finally, 4th and 5th generation networks determine a reduction of the CO2 emissions by the 98% and the 87%, respectively. The development of innovative district heating and cooling systems is crucial for the reduction of the environmental impact of buildings sector. However, for residential applications, novel 5th generation networks do not exhibit a better energy and economic performance with respect to mature 4th generation networks, due to the scarce simultaneous heating and cooling demand.

Thermodynamic and Thermo-Economic Analysis of a Solar-Integrated Double-Turbine Kalina Cycle for Varying Solar Flux Conditions

Abstract Kalina cycle is established as a reliable low-grade energy cycle working on solar, geothermal, and other waste heat recovery sources. This work aims to develop a novel methodology for optimizing a Kalina cycle according to the solar irradiation. A comprehensive analysis of performance is conducted by varying the parameters of the Kalina system, modeled with high- and low-pressure turbines. The present work implements and analyzes the performance of a multi turbine Kalina cycle with cylindrical parabolic collectors for energy input at different time, on a particular day, for a location. The proposed cycle is modeled to simulate the working. The dependency of parameters—separator pressure, concentration of ammonia in boiler, intermediate separator temperature and vapor fraction at condenser side turbine exit—on the system performance is investigated. Optimization is conducted using genetic algorithm with net power as objective function for different solar irradiations. The optimized power values are 282.62, 246.75, 222.31, and 180.0 kW for solar influxes 507.7, 461.8, 413.9, and 321.0 W/m2 respectively. The results show that the proposed model can be adopted for better performance. A thermo-economic analysis of an optimized output is conducted to conclude on capital investment and operation cost for sustainable power production. The analysis yields highest cost rate of exergy destruction of 58936.41$/year for the boiler. The investment cost of the turbines together is 89% of the total capital investment, and hence, thermo-economic factor is highest for these components.

Herbal biochar preparation and its application as soil amendment: Is such disposal of traditional Chinese medicine residue cost-efficient towards carbon neutrality?

Herbal biochar from traditional Chinese medicine residue (TCMR) and related carbon-negative utilization could contribute to the realization of carbon-neutral disposal process of TCMR. For this purpose, herbal biochar preparation by low-temperature pyrolysis and its application as soil amendment is designed, and the integrated effects are assessed by a combined techno-economic, exergy, thermoeconomic and life cycle analyses based on the accounting of material flow, energy flow and environmental flow. Firstly, the economic benefits (i.e., net present value, internal rate of return and payback period) of the system is analyzed by combination of cost-benefit method and sensitivity analysis. Secondly, exergy analysis determines exergy destruction, exergy destruction ratio, exergy destruction coefficient, energy efficiency and exergy efficiency of pyrolysis system. Furthermore, by combining techno-economic and exergy analyses, exergy destruction cost and exergy economic coefficient are calculated to optimize pyrolysis system. Thirdly, the CO2 mitigation cost, carbon neutrality potential and environmental impact are evaluated via combining life cycle assessment with techno-economic and exergy analyses. The results indicate that the higher pyrolysis temperature shows preferable exergy efficiency, energy efficiency and thermodynamic performance. From 400 to 600 °C, herbal biochar preparation and its application can improve economic benefits by 12.9–15%. At 550 °C, such TCMR disposal process can reduce environmental impact to −8651.65 mPts, and the GHG emissions and CO2 mitigation cost of the life cycle process are 395.1 kg CO2-eq/t feedstock and 63.4 CNY/t CO2-eq, respectively. In general, herbal biochar preparation by low-temperature pyrolysis and related application as soil amendment can realize the carbon-negative disposal of TCMR by an economical and efficient way.

Thermoeconomic Analysis of Heat Pump Preheating For Fluidized Bed Drying Process

Enerji verimliliği, küresel ısınma ve iklim değişikliği günümüzde üzerinde durulan en önemli konuların başında gelmektedir. Tüketilen enerjinin etkin ve verimli kullanımına ilişkin yeni tasarımlar yaparken de tasarımlarda kullanılacak yenilikçi ve verimli teknolojiler ekonomi ve çevresel olumsuz etkilerin azaltılmasına katkı sağlayacaktır. Bu çalışmada; tamamen gaz yakıcı bir cihazla çalışan döküm sektöründe kullanılan akışkan yataklı bir kum kurutma sistemine ısı pompası entegre edilerek doğalgaz tüketimi azaltılmaya ve bu sayede sistem kullanıcılarına doğrudan ve dolaylı kazanımlar yaratılmaya çalışılmıştır. Sudan suya çalışan ve çevre dostu R32 soğutucu akışkanı kullanılarak 20°C’deki ortam havasını 45°C’ye ön ısıtma yapacak şekilde tasarımı yapılan ısı pompası sisteminin performans katsayısı (COPIP) 3,88 olarak hesaplanmıştır. Isı pompası entegrasyonu sayesinde sistem yıllık 36.839,1 Nm3 doğalgaz tasarrufu gerçekleştirilecektir. Bu entegrasyon ile sistemin yıllık çalışma süresi, elektrik ve doğalgaz birim maliyetleri baz alınarak, işletmecisine 193.501,25 ₺/yıl mali tasarruf sağlayacağı öngörülmektedir. Sisteme entegre edilen ısı pompasının; ekipman ve kurulum fiyatı, güncel kur değeri ile yıllık mali tasarruf miktarı parametreleri dahilinde, sistemin amortisman süresi 1,50 yıl olarak hesaplanmıştır. Ayrıca sistemde kurulacak fotovoltaik paneller ile enerji üretilerek karbon emisyonunun azaltılabileceği ve yine fotovoltaik panellerin marifetiyle işletmeci firmaya ek bir gelir kalemi oluşturulabileceği de öngörülmektedir.

Parametric Analysis of the Solar-assisted Intercooled Gas Turbine and Organic Rankine Cycle for Waste Heat Recovery and Power Production

The energy consumption has gradually increased in the current context. Fossil fuels are the primary source of energy for the world’s population. Furthermore, energy derived from fossil fuels has significant disadvantages, including increased pollution and global warming. Solar energy is the fastest-growing alternative to fossil fuels among the various energy options. As a result, the focus of the present work is on the thermo-economic analysis of a hybrid solar-assisted intercooled gas turbine (GT) and organic Rankine cycle (ORC) for waste heat recovery and power production at near-zero-emissions. The work outcome and maximum efficiency of the hybrid arrangement are 1342.12 kW and 71.12% respectively at the cycle pressure ratio of 8, and 443 K entry point turbine temperature. The economic model of the integrated system depicts that the unit power production cost for the combined system has been evaluated as 1932 e per kW.

Efficiency improvement and Thermo-economic analysis of proton exchange membrane fuel cell system with energy recovery for both air and hydrogen

Proton exchange membrane fuel cells (PEMFCs) supplies as one of the promising solutions for carbon neutrality in transportation. However, excessive energy consumption of the auxiliary equipment remains one of the major obstacles in realizing large-scale commercialization. Therefore, in this study, a novel PEMFC system with energy recovery for both air and hydrogen was developed to enhance the energy efficiency. A zero-dimensional thermodynamic model was established to forecast and estimate system's performance. Additionally, the economic analysis considering cost sensitivity was conducted to provide feasibility evidence. The effects of current density, cathode air pressure, and turbo-expander cost on the system's efficiency and economic revenue were investigated. The results showed that the energy recovery effect and economic revenue increase with an increase in current density when the operating temperature constant was kept constant and increase with an increase in cathode air pressure when the current density constant was kept constant. Compared to that of the conventional PEMFC system, the system's efficiency of the novel model increased by 6.27%, corresponding to a current density of 1.21 A/cm2 when the cathode air pressure remains constant at 0.31 MPa. The lower of the cost of the turbo-expanders, the higher of the net revenue. The PEMFC system with turbo-expanders can achieve more revenue at larger current density and cathode air pressure conditions.

Thermoeconomic Analysis of Concentrated Solar Power Plants Based on Supercritical Power Cycles

Solar thermal power plants are an alternative for the future energy context, allowing for a progressive decarbonisation of electricity production. One way to improve the performance of such plants is the use of supercritical CO2 power cycles. This article focuses on a solar thermal plant with a central solar receiver coupled to a partial cooling cycle, and it conducts a comparative study from both a thermal and economic perspective with the aim of optimising the configuration of the receiver. The design of the solar receiver is based on a radial configuration, with absorber panels converging on the tower axis; the absorber panels are compact structures through which a pressurised gas circulates. The different configurations analysed keep a constant thermal power provided by the receiver while varying the number of panels and their dimensions. The results demonstrate the existence of an optimal configuration that maximises the exergy efficiency of the solar subsystem, taking into account both the receiver exergy efficiency and the heliostat field optical efficiency. The evolution of electricity generation cost follows a similar trend to that of the exergy efficiency, exhibiting minimum values when this efficiency is at its maximum.

Thermo-Economic Analysis of Simple Cycle Steam Power Plant

Thermo-Economic Analysis of Simple Cycle Steam Power Plant

Thermo-economic analysis and multi-objective optimization of solar aided pumped thermal electricity storage system

The concept of solar energy aided pumped thermal electricity storage (Solar-PTES) was proposed to improve the round-trip efficiency, as well as the solar energy utilization efficiency. The thermodynamic model was developed for such Solar-PTES system with the nominal electricity input of 5 MW and the nominal storage capacity of 6 equivalent hours. Taking the round-trip efficiency, energy density and levelized cost of storage as indicators for system performance, the effects of main design parameters were investigated, including that of main components performance parameters and cycle state parameters. The multi-objective optimization algorithm was applied for optimizing three performance metrics and the trade-off analysis was performed. The results indicates that the round-trip efficiency drops with the growing energy density, while the levelized cost of storage firstly decreases as the round-trip efficiency drops and then slightly rises. The minimum case of levelized cost of storage is selected for investigation. In that case, solar heat input is 5.05 MW and solar energy utilization efficiency of Solar-PTES system is 35.7 %. The nitrogen mass flow rate is 27.54 kg/s. The round-trip efficiency, energy density and levelized cost of storage for Solar-PTES system are 68.1 %, 16.63 kWh/m3 and 0.143 ± 0.023 $/kWh, respectively.

An innovative approach for utilizing waste heat of a triple-pressure cogeneration combined cycle power plant by employing TRR method and thermodynamic analysis

The aim of this study is to examine the possible locations where heat recovery can occur in a triple-pressure cogeneration combined cycle power plant and calculate the amount of waste heat that can be recovered. To complete this objective, an adjusted cycle layout is created and the energy system is analyzed from both thermodynamic and exergetic viewpoints. Furthermore, the Total Revenue Requirement (TRR) method and thermoeconomic analysis are used to determine the price of products produced. The optimization results are displayed in a Pareto chart diagram, utilizing a new model with two objective functions - power cost and product heat. This method allows for identifying the best operating point for these types of power plants, accounting for electricity and heat prices across various regions. The implications of this study for the energy sector are significant as it highlights how waste heat recovery plays a crucial role in cogeneration combined cycle power plants. By pinpointing potential heat recovery locations and determining how much waste heat can be recovered, valuable insights are gained that can inform both design and operation decisions for these power plants. Additionally, using the TRR method and thermoeconomic analysis provides a comprehensive framework for evaluating the economic feasibility of this type of system.

Qualitative review of thermoeconomic analyses in solar refrigeration systems applied to absorption chillers

The implementation of solar refrigeration in absorption chillers has been a topic widely researched in the scientific community in view of the search for compatibility of the thermal comfort standards required in the current century with the need to search for the consumption of sustainable energy sources in refrigeration equipment. Based on this scenario, this work aimed to conduct a qualitative literature review of thermoeconomic analyses in solar cooling systems applied to absorption chillers. As a result, a volume of research was obtained in three basic categories: energy and exergetic analyses in low capacity chillers, effect of the climate on the thermoeconomic performance of absorption systems by solar refrigeration and the implementation of cogeneration systems using solar energy as one of the sources.

Thermo-economic analysis for a novel grid-scale pumped thermal electricity storage system coupled with a coal-fired power plant

Combining pumped thermal electricity storage with existing thermal power plants can be a promising technical route for developing large-scale grid energy storage technologies for stably consuming renewable power. In this paper, a novel pumped thermal electricity storage system coupled with a supercritical coal-fired power plant is designed based on cascade heat storage. The thermodynamic analysis shows that the round-trip efficiency of the integrated system can reach 0.53–0.56 under 60–100% output load, for a practical design with a recuperation temperature of 280 °C and compressor outlet temperature of 500 °C. An economic analysis is performed and indicates this design can achieve a payback period of around 4 years considering a moderate charging electricity price of 3 ¢/kWh and a long storage period of 12 h. Further decreasing the recuperation temperature and increasing the compressor outlet temperature can reduce the system investment cost and LCOE, while it requires technological advancement of molten salts working at a wider temperature range and more robust compressors. In comparison to the integrated system with conventional two-tank storage, as well as other storage systems like vanadium redox flow batteries, the current design has a more attractive cost and can be scaled up in future multi-energy applications.

Exergy cost accounting thermoeconomic analysis of an oil refinery operating at off-design conditions

ABSTRACT Reducing crude oil quality affects the refinery capacity, quality for downstream units, and overall economics. The thermoeconomic model of a refinery can show that the effects of faults generally propagate through the whole process and affect the behavior of several components, resulting in induced malfunction in typical components. This study aims to estimate the primary source of inefficiency and, therefore, the main reason for the increase in irreversibility and entering feed into the refinery due to changes in some operating conditions. Operating conditions in 2013 and 2023 are defined as base mode and operating mode, respectively. The results of exergy cost analysis show that Liquefied Petroleum Gases (LPG) unit and H2S removal unit have the greatest impact on reducing the overall performance of the refinery in 2023, while this unit is one of the units with the least exergy destruction in the base year. The share of the environment and fuel oil unit, LPG unit, H2S removal unit, and kerosene treating unit in increasing the irreversibility of the utility unit is 4,898.18, 1200.67, 935.15, 642.73, and 624.45 GJ/day, respectively. The share of the Crude Distillation Unit (CDU) in the reduction of the irreversibility of the utility unit is 7,316.67. The results show that the total resource consumption has increased by 168 MJ/day. Therefore, in order to reduce resource consumption in 2030 (operational mode), the impact of LPG and H2S removal units on utility irreversibility should be controlled.

Thermoeconomic and life cycle assessments for a trigeneration system: A case study

ABSTRACT The current need to diversify the global energy matrix implies introducing renewable energy sources and evaluating commercially available solutions. This study assesses a trigeneration system from thermoeconomic and environmental viewpoints, employing the Theory of Exergy Cost and Life Cycle Assessment. The location of the theoretical study case is the state of Pernambuco, Northeast Brazil. The trigeneration system operates on biogas and is comprised of four subsystems: biogas purification, molted carbon fuel cell, combined cycle, and absorption refrigeration system. The energy services produced are electricity, heat (hot water), and cooling. The results of the thermoeconomic analysis revealed that the energy system requires an electricity tariff of at least US$ 106.76/MWh to generate revenue due to the high costs associated with the purchase of biogas and capital costs of the equipment for biogas purification and fuel cell. The life cycle assessment identified that the biogas purification step presented the highest environmental impacts due to the material composition of the absorption and regeneration columns, which is interesting as this is the most critical step of the process. LCA results indicate that although methane is a vital energy vector for energy transition, further studies are required on the technical and environmental aspects of its use in energy systems.

Mathematical and thermo-economic analysis of thermal insulation for thermal energy storage applications

Thermal energy storage (TES) is vital for achieving carbon neutrality in the energy sector. To achieve high storage efficiency, insulation with satisfactory performance is required. However, in the field of TES, limited attention has been paid to thermal insulation wherein the exergy loss under periodic operation conditions must be considered. In this study, we derived an analytical solution for the transient heat conduction equation and obtained a concise and explicit expression of the average exergy loss rate under a typical operation mode, where the variation of the internal temperature is a rectangular wave function. The effects of parameters such as the operation temperature, Biot number, Fourier number, insulation thickness, thermal conductivity, and volumetric heat capacity were discussed, and the insulation thickness was optimized by using the life-cycle cost analysis method. The transient effect caused by temperature fluctuations is expected to increase exergy loss. In addition to thermal conductivity, volumetric heat capacity has a considerable influence on insulation performance. In a real-world case, if the transient effect is ignored, the estimated exergy loss is 15.4%–62.5% smaller when the insulation thickness varies from 0.1 to 0.4 m, with the optimal thickness being 27.5% larger, resulting in an additional economic cost of 1.86%.

Thermo-economic performance limit analysis of combined heat and power systems for optimal working fluid selections

In previous works, we have proposed the thermodynamic performance limit analysis methodology for the organic Rankine cycle for analyzing the impact of working fluid properties on system performance. Here the concept is extended to the thermo-economic performance limits, and is applied to a combined heat and power system based on an organic Rankine cycle. Working fluids are characterized with 8 characteristic thermodynamic and transport properties based on a corresponding state model and a residual entropy scaling approach. The 8 fluid characteristic properties along with 3 system operational parameters are optimized using a multi-objective genetic algorithm; a Monte Carlo algorithm is further adopted to avoid sub-optimal convergences. As the result, the performance limits could be well represented by the trade-off (Pareto front) between the maximized thermal efficiency and minimized payback period. The impact of the fluid characteristic properties on both thermodynamic and economic targets is investigated and ultimately guided the choice of working fluids: low molar mass, low thermal conductivity scaling factor, high viscosity scaling factor and high critical pressure are always preferred. "Wet" working fluid is preferred for a high thermal efficiency while "dry" working fluid is favored for a short payback period. Critical temperature has the most profound impact, while ideal gas isobaric heat capacity and acentric factor have negligible impacts. The choice of working fluid, system design (e.g., recuperative effectiveness) and system operational parameters (e.g., evaporation temperature) highly depends on the given hot sources and the preferences to the thermodynamic and economic targets.

Performance study of thermal-nuclear co-generation system based on exergy and thermal economy analysis

The thermal-nuclear co-generation system realizes the effective complementarity of power generating efficiency and pollutant emission reduction while simultaneously reducing the consumption of fossil fuels and pollutant emissions. First, four potential combined thermal-nuclear power generation schemes are proposed in this research. The performance of each scheme is examined, and the system is compared and examined based on two indicators: nuclear energy share and nuclear energy generation efficiency. For the chosen ideal combination scheme, exergy analysis and a thermo-economic structural theory analysis are carried out. The examination of the assembly for the Direct heating scheme, which the study's findings indicated was the optimum option, revealed that the combined unit could achieve 38.14% assembly efficiency, which is 2.29% greater than that of the nuclear unit alone. The feasibility of combining thermal and nuclear power is demonstrated by the study of the influence of the key parameters on the cost per unit of assembly and the calculation that the co-generation system's economic efficiency is higher than that of nuclear or thermal power units built separately in terms of fuel economy.

Thermo-economic analysis of a polygeneration system using biogas and waste tire based on the integration of solid oxide fuel cell, gas turbine, pyrolysis, and organic rankine cycle

To optimize the biogas power generation process and waste tire disposal, a novel polygeneration system has been conceptualized. The hybrid design comprises a solid oxide fuel cell-gas turbine subsystem, tire pyrolysis reactor, organic Rankine cycle, and waste heat recovery subsystem. The biogas is first utilized by the solid oxide fuel cell and gas turbine for power generation. Subsequently, the high-temperature exhaust is utilized to preheat the fuel and oxidant and to heat the pyrolysis reactor and organic Rankine cycle, thereby improving the power generation and energy conversion efficiency. A comprehensive case study has been carried out to verify technological and economic feasibility of the proposed scheme. The results demonstrate that the net energy efficiency of the system is 70.11 % with an exergy efficiency of 69.65 %, and that the hybrid system maintains a high level of performance even when the fuel cell operating temperature varies. The irreversibility mainly arises from the pyrolysis reactor, cell stack, and combustion chamber. The new design requires only an initial investment of 722.93 k$ and can be recovered in 5.09 years with a net present value of 1795.51 k$ over its 25-year service life. Therefore, the proposed system is highly promising and suitable for implementation.

Thermo-economic analysis of a low-cost greenhouse thermal solar plant with seasonal energy storage

Reduction of greenhouse gas emissions is today mandatory to limit the increase of ambient temperature. This paper provides a numerical study of a thermal solar plant using a seasonal dual-media sensible heat thermal energy storage system for supplying the total energy demand of a greenhouse located in the South of Italy, avoiding the use of the gas boiler. The aim of the work is to assess the technical and economic performance of a low-cost pit storage system, made of gravel and water, placed under the greenhouse to save surface. The study provides an original analysis of the charging and discharging phases during one year of operation on the basis of the real hourly heating demand and on real weather data. A sensitivity analysis of the levelized cost of heat is carried on with respect to the solar-collector area and to the storage-pit volume. The analysis shows that a minimum-cost design solution exists to cover 100% of the heat demand with an estimated levelized cost of heat of 153.3 EUR/MWh. The results demonstrate that dual-media thermal energy storage systems with solar thermal collectors represent a viable solution for reducing the environmental impact of greenhouses.

Development of selection criteria of zeotropic mixtures as working fluids for the trans-critical organic Rankine cycle

The trans-critical organic Rankine cycle (TCORC) can achieve a better thermal match in the heating process of the working fluid compared to the subcritical cycle. By using zeotropic mixtures as working fluids, the thermal match in the cooling process can be further optimized, reducing the system's irreversibility. As the selection criteria are not systematically formulated, screening zeotropic mixtures for the TCORC is challenging. In this work, the thermodynamic and thermo-economic analysis was carried out to investigate how the thermal match in the heating/cooling processes affects the system performance, which is represented by the overall exergy efficiency and the levelized energy cost. Results show that the mixture's critical temperature is a key factor influencing the system performance. Then, the mixtures having a proper condensation temperature glide can further improve the system performance. The thermo-economic analysis shows that the mixtures selected according to these criteria can also provide better thermo-economic performance, although the heat exchanger area has been enlarged during the improvement of the thermal match in heat exchangers.