Total Exergy Efficiency Research Articles

Thermo-economic optimization of a new solar-driven system for efficient production of methanol and liquefied natural gas using the liquefaction process of coke oven gas and post-combustion carbon dioxide capture

The suitable use of hydrogen-containing industrial by-products such as coke oven gas (COG) leads to a reduction of environmental pollution and energy waste. This paper develops a novel integrated structure for the simultaneous production of portable and relatively clean liquid fuels from COG and power plant exhaust gases. The subsystems include a CO2 capture unit to separate carbon dioxide from exhaust gases, natural gas purification and liquefaction process to produce liquefied natural gas (LNG), and a methanol production cycle. Photovoltaic panels with a geographical location in Iran are used to provide the required power. This process provides 1.287 kg/s of methanol and 1.678 kg/s of LNG as the main product and 46 kg/s of hot water as an industrial utility. The integrated structure's total energy and exergy efficiencies are 65.36% and 68.72%, respectively. The largest share of exergy degradation belongs to the photovoltaic panels (81.33%), heat exchangers (5.66%), and distillation towers (3.152%). The results of the economic assessment show that the payback period and the prime cost of product are 4.29 years and 0.3967 US$/kg methanol. The sensitivity analysis outcomes demonstrate that the efficiency of the whole process and the prime cost of the product increase to 69.05% and 0.4005 US$/kg methanol when the hydrogen content of the coke oven gas decreases from 65 to 54 mol%. Moreover, the flow rate decrease of COG from 991.6 to 901.6 kmol/h, reduces the prime cost of the product and the irreversibility of the whole system to 0.3855 US $/kg methanol and 55382 kW. Thermo-economic optimization of the hybrid system based on the non-dominated sorting genetic algorithm is implemented with TOPSIS and LINMAP being the decision-making methods. From the optimization results, the optimum values for the efficiency of the whole hybrid system and the prime cost of the methanol are calculated to be 65.83% and 0.3611 US$/kg methanol.

Designing and thermodynamic optimization of a novel combined absorption cooling and power cycle based on a water-ammonia mixture

The efficiency of generating power and cooling can be enhanced by using cogeneration systems. To simultaneously generate cooling and power, a novel ammonia-water cogeneration system driven by waste heat recovery is presented. In the proposed system, the boiler and condenser work at the non-isothermal and isothermal phase changes, respectively. To evaluate the novel cycle, firstly, for heat source temperature of 473K, the effect of maximum pressure of cycle and ammonia concentration is investigated. Considering the results, increasing ammonia concentration decreases the ratio of net power to cooling capacity while increasing maximum pressure increases the net power to cooling capacity ratio. At various ammonia concentrations and the constant pressure of 25 bar, the maximum exergy efficiency occurs at a concentration of 89%. Also, at a constant concentration of 85% and various maximum pressures, the optimum exergy efficiency occurs at 34 bar. To optimize the proposed system, the selected objective function is the total exergy efficiency. So, by a genetic algorithm, at a heat source temperature of 473K, the concentration and pressure are optimized at the values of 88.28% and 31.1 bar, respectively. Eventually, the optimum values of pressure and concentration for various heat source temperatures are presented in a table.

Modeling and comprehensive analysis of food waste gasification process for hydrogen production

To realize the utilization of food waste, a novel hydrogen production process for food waste gasification is proposed in this study, which converts food waste into hydrogen. Using Aspen Plus, the effects of gasification temperature and regional differences on the hydrogen production capacity were studied. It was found that the hydrogen capacity was improved by increasing temperature, while the regional effect was not significant. Based on the simulation results, a comprehensive evaluation of the hydrogen production process was conducted by analyzing exergy efficiency, economic benefits, and environmental costs to further explore the feasibility of the process. The exergy results show that the total exergy efficiency of this process is 64.86%, indicating a high energy conversion efficiency. From the economic perspective and based on economic indicators such as material consumption, production cost, and total capital investment, the total capital investment of the process is 1.61×107 USD. Furthermore, the potential for environmental protection is evaluated by analyzing the global warming and acidification potentials of the hydrogen production process. The hydrogen production capacity of the food waste-to-H2 process is 1.2 t/h H2, indicating a substantial hydrogen yield. This process can accelerate the implementation of the carbon neutrality goal to a certain extent.

Energy, Exergy, and Economic Analysis of Cryogenic Distillation and Chemical Scrubbing for Biogas Upgrading and Hydrogen Production

Biogas is one of the most important sources of renewable energy and hydrogen production, which needs upgrading to be functional. In this study, two methods of biogas upgrading from organic parts of municipal waste were investigated. For biogas upgrading, this article used a 3E analysis and simulated cryogenic separation and chemical scrubbing. The primary goal was to compare thermoeconomic indices and create hydrogen by reforming biomethane. The exergy analysis revealed that the compressor of the refrigerant and recovery column of MEA contributed the most exergy loss in the cryogenic separation and chemical scrubbing. The total exergy efficiency of cryogenic separation and chemical scrubbing was 85% and 84%. The energy analysis revealed a 2.07% lower energy efficiency for chemical scrubbing. The capital, energy, and total annual costs of chemical absorption were 56.51, 26.33, and 54.44 percent lower than those of cryogenic separation, respectively, indicating that this technology is more economically feasible. Moreover, because the thermodynamic efficiencies of the two methods were comparable, the chemical absorption method was adopted for hydrogen production. The biomethane steam reforming was simulated, and the results indicated that this method required an energy consumption of 90.48 MJkgH2. The hydrogen production intensity equaled 1.98 kmoleH2kmolebiogas via a 79.92% methane conversion.

Thermodynamic and economic analysis of a directly solar-driven power-to-methane system by detailed distributed parameter method

The transformation of solar energy into easily transportable and storable fuel brings a prospective solution to the issue caused by its intermittency and non-dispatching. Relying on well-established infrastructures and mature technologies for application, methane can be an attractive energy carrier for improving the penetration of solar energy in the future energy structure. To evaluate the feasibility of solar-to-methane from technical and economic views, this paper proposes a directly solar-driven power-to-methane system integrating photovoltaic plant, solid oxide electrolysis cell, methanation reactor, and membrane module. The detailed distributed parameter method is employed for thermodynamically modeling the core components of the system to consider the profiles of current density, temperatures, and composition concentrations. A comprehensive thermodynamic and economic analysis is further conducted for the system, and the results indicate that the power-to-methane efficiency, total energy efficiency, and total exergy efficiency of the system can reach 68.41%, 9.88%, and 11.08%, respectively. With the annual average solar radiation of 557.43 W/m2, the system achieves an annual synthetic natural gas yield of 914.51 MWh/y. A high total product unit cost of 186.57 $/MWh is obtained in 2020, whereas it is predicted to decrease to 91.51 $/MWh (about 51% reduction) in a future scenario with a payback period of 4.66 years due to the significant decrement of the photovoltaic investment cost. The present work reveals the engineering realizability and economic viability of solar-to-methane and provides a competitive option for the development of solar energy.

A novel carbon dioxide capture system for a cement plant based on waste heat utilization

A novel carbon dioxide capture system that combines cooling, heating and power (CCHP) based on a cement plant has been developed and evaluated. The proposed integration is realized by recovering the waste heat of cement flue gas to produce electricity for decarburization or sale. The novel system can reduce the expensive external energy consumption for decarbonization by fully utilizing the heat itself. The heat loss of the CO2 capture process is utilized to supply heat directly or provide cooling by an NH3-H2O absorption refrigeration system. An appropriate decarbonization rate (18.89 %) is determined when the income just as much as possible compensates for the cost of decarbonization. The coupled system is assessed from thermodynamic and economic perspectives to exhibit its feasibility. Under the heating mode, 5.52 MW energy is recovered from the decarbonization heat loss. Meanwhile, a total system efficiency of 10.28 % and a total exergy efficiency of 8.18 % can be achieved. Both metrics are superior to the cooling mode, in which 3.66 MW energy is taken into the absorption refrigeration system for suppling 0.82 MW of cooling. Finally, the annual income achieves 3287.07 k$ while the COA as low as 46.31 $/t CO2 under this decarbonization rate.

Parametric layout and performance examination of a novel energy process based on the renewable energies and thermodynamic cycles

Abstract Today, due to the challenges of fossil fuels and environmental crises, the use of geothermal energy as a renewable energy source can be useful. Since the two wells used for Sabalan geothermal power plant have different thermodynamic, in the present article, a new combined layout based on two flash cycles is proposed and investigated. In the introduced energy cycle, the transcritical Rankin and Kalina cycles are also used as downstream cycles to generate more power. In addition, heat exchangers are used to transfer heat to the liquefied natural gas (LNG) cycle to prevent energy and exergy losses in the downstream cycles. Relying on the proposed layout can prevent heat loss of downstream cycle’s condensers. LNG cycle, in addition to generating more power by using heat losses, can supply natural gas to the system and suburban villages. It was determined that the proposed energy cycle is able to produce a net power of ~27.8 MW with a thermal efficiency of ~26%. In addition, the total exergy destruction and exergy efficiency of the cycle are 29.9 MW and 52.6%, respectively. The proposed energy cycle is evaluated from the energy and exergy points of view. In addition, a parametric evaluation is presented to assess the effect of various factors on the performance of the proposed energy cycle. Moreover, the net power and performance of the energy cycle have been optimized subject to various input variables using a genetic algorithm.

New Integrated Process for the Efficient Production of Methanol, Electrical Power, and Heating

In this paper, a novel process is developed to cogenerate 4741 kg/h of methanol, 297.7 kW of electricity, and 35.73 ton/h of hot water, including a hydrogen purification system, an absorption–compression refrigeration cycle (ACRC), a regenerative Organic Rankine Cycle (ORC), and parabolic solar troughs. The heat produced in the methanol reactor is recovered in the ORC and ACRC. Parabolic solar troughs provide thermal power to the methanol distillation tower. Thermal efficiencies of the integrated structure and the liquid methanol production cycle are 78.14% and 60.91%, respectively. The process’s total exergy efficiency and irreversibility are 89.45% and 16.89 MW. The solar thermal collectors take the largest share of exergy destruction (34%), followed by heat exchangers (30%) and mixers (19%). Based on the sensitivity analysis, D17 (mixture of H2 and low-pressure fuel gas before separation) was the most influential stream affecting the performance of the process. With the temperature decline of stream D17 from −139 to −149 °C, the methanol production rate and the total thermal efficiency rose to 4741.2 kg/h and 61.02%, respectively. Moreover, the growth in the hydrogen content from 55% to 80% molar of the feed gas, the flow rate of liquid methanol, and the total exergy efficiency declined to 4487 kg/h and 86.05%.

Thermodynamic and economic sensitivity analyses of a geothermal-based trigeneration system; performance enhancement through determining the best zeotropic working fluid

In this paper, a novel geothermal-based trigeneration system producing electricity, cooling, and freshwater is devised. The whole setup comprises a flash-binary geothermal cycle, an ejector refrigeration cycle, a dual-pressure organic Rankine cycle, and a reverse osmosis unit. In the dual-pressure organic Rankine cycle, the utilization of the zeotropic mixture is examined for performance improvement. The overall system is analyzed from energy, exergy, and economic viewpoints. Likewise, the system is inspected by the thermodynamic and economic sensitivity analyses based on the best working fluid. By specifying the Butene/Isopentane zeotropic mixture as the best working fluid, it is revealed that from 10932kW of the input exergy to the system, 5561.74kW is destructed within different components. In this way, the recovered exergy rate by net output electricity is equal to 3633.33kW, by cooling load is 1663.44kW, and by freshwater is 104kW. Also, the optimum net output power and total energy and exergy efficiencies were obtained to be 3.65 MW, 25.06%, and 35.06%, correspondingly. In this situation, the sum unit cost of products and payback period of the system were 14.50 $.GJ−1 and 3.66 years, respectively.

Numerical analysis of a small sized water based solar photovoltaic-thermal collector

ABSTRACT Large-sized collectors suffer from heat loss from its top due to large aperture plane area. In this work, numerical investigation is performed on a small-sized solar-based photovoltaic thermal water collector using a channel type absorber to analyze its performance under different operating and ambient conditions. A 3D numerical model is developed using COMSOL multi-physics software and the thermal and hydraulic performances of the PV-T collector are carried out. The influence of Reynolds number on the Nusselt number is enumerated for a given operating temperature range and solar radiation level. The variations of PV cell temperature, channel water temperature, thermal and electrical efficiency, exergetic efficiency are studied under different mass flow rates, fluid inlet temperatures, and solar radiations, which majorly control the PV-T performance. It has been observed that with increase of Reynolds number heat transfer rate also increases, and as rate of flow increases from 0.004 kg/s to 0.08 kg/s, the electrical and thermal efficiencies also increase and achieve a maximum 89.96% and 11.47%, respectively. Moreover, uniform temperature distribution has been observed for varying mass flow rates under constant inlet temperature and solar radiation. In addition, a maximum total exergy efficiency of 14.68% is achieved at a mass flow rate of 0.02 kg/s, inlet temperature of 32°C and solar radiation of 900 W/m2. On the basis of the present investigation, a small-sized PV-T collector is recommended for future use as an efficient collector that can provide hot water and also electricity for small-scale domestic or industrial applications.

Performance Analysis of a Waste-to-Energy System Integrated with the Steam–Water Cycle and Urea Hydrolysis Process of a Coal-Fired Power Unit

An innovative hybrid energy system consisting of a waste-to-energy unit and a coal-fired power unit is designed to enhance the energy recovery of waste and decrease the investment costs of waste-to-energy unit. In this integrated design, partial cold reheat steam of the coal-fired unit is heated by the waste-to-energy boiler’s superheater. The heat required for partial preheated air of waste-to-energy unit and its feedwater are supplied by the feedwater of CFPU. In addition, an additional evaporator is deployed in the waste-to-energy boiler, of which the outlet stream is utilized to provide the heat source for the urea hydrolysis unit of coal-fired power plant. The stand-alone and proposed designs are analyzed and compared through thermodynamic and economic methods. Results indicate that the net total energy efficiency increases from 41.84% to 42.12%, and the net total exergy efficiency rises from 41.19% to 41.46% after system integration. Moreover, the energy efficiency and exergy efficiency of waste-to-energy system are enhanced by 10.48% and 9.92%, respectively. The dynamic payback period of new waste-to-energy system is cut down from 11.39 years to 5.48 years, and an additional net present value of $14.42 million is got than before.

Energy and exergy analyses of a cryogenic reverse Brayton cycle with waste heat recovery

In a typical reverse Brayton cycle (RBC), a great amount of compression heat is just wasted, for which there are two different temperature levels. The basic organic Rankine cycle (ORC) and the regenerative ORC with improvement were then applied to recover waste heat. Considering that the waste gas after ORC was reused, the total exergy efficiency was defined to evaluate different cycles. A simulation method was conducted to predict cycle performances and the coupling between RBC and ORC was clarified. The feasibility of replacing the after cooler with the evaporator was analysed. Compared with the typical RBC, a relative improvement of 18.2% was achieved for COP in the combined system and the cooling exergy efficiency was increased by 16.8%. The correspondence of the total exergy efficiency and the COP of whole system exited in different cycle layouts. Proper organisation of the RBC with ORC could promote the energy efficiency.

Soft computing based optimization of a novel solar heliostat integrated energy system using artificial neural networks

This study proposes and investigates a novel energy system based on biomass and solar energy. This plant is composed of a biomass unit, a solar unit, and a waste-heat recovery unit. This novel proposed integrated system can provide the needs such as electricity, hydrogen, freshwater, heating, and hot water production. For electricity generation, two gas turbines, one steam Rankine cycle, and one organic Rankine cycle are used. In contrast, for utilization of solar energy, a heliostat field, and for biomass conversion, a gasifier is used. In addition, the desalination unit and PEM electrolyzer are utilized to produce fresh water and hydrogen, respectively. Firstly, the present work aims to investigate the developed system from the exergoeconomic and environmental perspective. Multi-objective optimization is conducted to determine the maximum amount of exergetic efficiency and the minimum value of the cost rate. An artificial neural network (ANN) is employed as a mediator tool to accelerate the optimization process. The relation between objective functions and design parameters is studied utilizing ANN to obtain the plant optimal decision variables. Employing the Pareto Envelope-based selection algorithm II (PESA-II) method, the optimum amount for the total cost rate and exergy efficiency is found 224.1 $/h and 26.7%, respectively. In addition, three evolutionary-based optimization algorithms are applied to determine the optimum results of the suggested plant.

Optimization of a biomass-driven Rankine cycle integrated with multi-effect desalination, and solid oxide electrolyzer for power, hydrogen, and freshwater production

The current work is a study of electricity, hydrogen, and freshwater polygeneration system fueled by biomass fuel. Accordingly, innovative integration of a Rankine cycle, a multi-effect desalination, and a solid oxide electrolyzer cell has been considered utilizing a syngas production biomass combustion chamber. The waste heat and a part of the output electricity of the Rankine cycle have been employed to launch the desalination and electrolyzer units, respectively. The suggested polygeneration is analyzed from the thermodynamic and exergoeconomic viewpoints through developing a code in engineering equation solver software and a multi-criteria optimization via MATLAB software. Hence, the NSGA-II optimization method and decision-making TOPSIS technique have been implemented. The parametric study has been conducted based on the effect of biomass fuel mass flow rate, turbine inlet pressure, combustion chamber outlet temperature, and pinch point temperature difference of the steam generator on the thermodynamic and exergoeconomic variables of the whole system. Considering the total exergy destruction rate, exergy efficiency, and total unit exergy cost of products as objective functions, the suggested system achieved the optimum values of 17.64%, 7658.5 kW, and 26 $/GJ corresponding for these variables.

Thermo-economic analysis of a novel system integrating compressed air and thermochemical energy storage with solid oxide fuel cell-gas turbine

This paper proposes a novel system integrating compressed air and thermochemical energy storage with solid oxide fuel cell-gas turbine (SOFC-GT). During charging process, the compression heat drives methanol decomposition into syngas for converting its low-grade thermal energy into high-grade chemical energy and achieving hybrid storage of physical and chemical energies simultaneously. During discharging process, the SOFC-GT efficiently converts the stored energy into power based on energy cascade utilization, significantly improving the total exergy efficiency of the system. The effects of six key parameters on the thermo-economic performance of the system are studied by the sensitivity analysis, and the results show that the total exergy efficiency conflicts with the levelized cost of energy (LCOE). Therefore, the multi-objective optimization is carried out for the system from the thermodynamic and economic aspects, and the best trade-off is selected with the total exergy efficiency of 65.89% and LCOE of 126.48 $/MWh, in which the system can generate 7.22 MWh power and 2.37 MWh heating with the total energy efficiency of 89.76%.

Exergy and economic analyses of an innovative integrated system for cogeneration of treated biogas and liquid carbon dioxide using absorption–compression refrigeration system and ORC/Kalina power cycles through geothermal energy

Nowadays, it is undeniable that applying renewable energy kinds with the approach of maximizing the performance of energy systems owing to the rising trend of energy demand in the world. In this research, an innovative integrated structure for the cogeneration of biomethane (bioCH4) and liquid carbon dioxide (CO2) by unrefined biogas and exhaust fumes from power plants is developed. The cryogenic biogas upgrading process and CO2 capture cycle are used for the treatment of unrefined biogas and the exhaust fumes from the power plants, respectively. The absorption–compression cooling process and organic Rankine/Kalina power units through geothermal energy are used to provide refrigerate and power. The present integrated process generates 0.8434 kg/s bioCH4 and 2.631 kg/s liquid CO2 by receiving 2.368 kg/s untreated biogas, 21.32 kg/s flue gas, and 7922 kW heat flow from geothermal energy. The thermal and total exergy efficiencies of the hybrid system are achieved at 59.94% and 73.10%, respectively. Exergy analysis depicts that the heat exchangers (4043 kW) and distillation columns (1857 kW) have the most exergy destruction in the among of equipment, which is 39.12% of the total system destruction. The heat exchanger network related to the multi-stream exchanger HE16 is extracted by pinch method. The economic assessment illustrates that the return period and the prime cost of the product are equal to 4.45 years and 0.8189 US$/ m3 bio-methane, respectively. The sensitivity investigation illustrates that the total thermal efficiency increases up to 72.50% and geothermal heat duty decreases to 7808 kW with the increase of methane composition in the untreated biogas from 55 mol% to 75 mol%. The return period increases up to 2.235 years and the net annual benefit decrease to 16.73 MMUS$/year when the bio-methane cost decreases from 2.5 US$/m3 to 0.5 US$/m3.

Energy, exergy, economic, environmental (4E) approach to assessing the performance of a photovoltaic-thermal system using a novel ternary nanofluid

Ternary nanofluids are a new type of fluids with three nanoparticles dispersed in a base fluid, and they have been experimentally shown to have improved thermophysical and rheological properties as compared to conventional or hybrid nanofluids. This study presents a numerical computation of investigating the performance of Photovoltaic/thermal collectors by utilizing Al2O3-ZnO-Fe3O4/water ternary nanofluid. The preparation of the nanofluid was done using a two-step method and analyzed for stability using Zeta potential analysis. The effect of the mixture ratio of the nanofluid on the thermal and electrical efficiency of the Photovoltaic/thermal system is investigated. The price-performance factor of the ternary nanofluid is firstly computed to determine the optimum volume concentration for practical application. This study also investigates the effect of nanofluid mass flow rate, volume fraction, mixture ratio and solar irradiation on the Photovoltaic/thermal system. From an economic standpoint, the system was estimated using the Price-performance factor and results showed that the 0.5 vol% Al2O3-ZnO-Fe3O4 ternary hybrid nanofluid was most suitable for laminar flow and turbulent flow regimes. The optimum electrical and thermal efficiency measured in this study was 13.75% and 59.38% respectively. This study also recorded an optimum cell temperature reduction of 8.81 °C. The mixture ratio measured for optimum PV/T performance was 0.33. The maximum exergy efficiency and PV/T total exergy efficiency recorded are 1.53% and 14.77%. The ternary nanofluid based PV/T system saved 19948.04 kgCO2 annually, as compared to 18719.88 kgCO2 when water was used as heat transfer fluid. The payback period was calculated to be 2.63 years for the ternary hybrid nanofluid based PV/T system.

Investigation on energy-efficient extractive distillation for the recovery of ethyl acetate and 1,4-dioxane from industrial effluent

Conventional extractive distillation processes have been proposed to separate the ternary ethyl acetate-1,4-dioxane-water system with azeotropes. Energy-efficient extractive thermally coupled processes with heat integration have been developed to reduce energy consumption. A macro-analysis of the energy, exergy, economy, and environment is conducted to estimate the economic and environmental benefits. The results proved that an extractive dividing-wall column with a heat-integrated process possessed the greatest energy-saving potential, delivered best economic performance and exhibited highest exergy efficiency. Compared to those of a conventional direct extractive distillation process, the total energy requirement and total annual investment cost are reduced by 28.18% and 24.28%, respectively, by the best energy-saving process. The total exergy efficiency of it is 1.779%. The proposed cleaner and sustainable extractive dividing-wall column configuration could achieve energy saving, investment reduction, and effectively enhance the exergy efficiency.

Performance assessment and optimization of two novel cogeneration systems integrating proton exchange membrane fuel cell with organic flash cycle for low temperature geothermal heat recovery

In order to realize the collaborative utilization of the low-grade geothermal energy and proton exchange membrane fuel cell (PEMFC) waste heat, this study proposes two novel combined systems integrated PEMFC with organic flash cycle (OFC) driven by geothermal energy. And the proposed systems are named as the enhanced power generation (EPG) cycle which can produce more electricity output, and the combined cooling and power (CCP) that can provide more cooling capacity. The thermodynamic and economic models are established to study the combined system performance. And the results show that under given conditions, the total thermal efficiency of EPG and the CCP achieves 8.50% and 8.83%, while the total exergy efficiency is 36.77% and 34.11%, respectively. The exergy analysis shows that the components with the major exergy destruction in these two systems are flashers, condensers and boilers. Parameter analysis shows that the heat source temperature, condensation temperature, fuel cell operating temperature, operating pressure and current density have the key impacts on the proposed system performance. Furthermore, the multi-objective optimization and decision making for the two combined systems are carried out. And the five Pareto frontiers with different organic working fluids (R600, R123, isobutene, R245fa and butane) are obtained.

Energetic and Exergetic Performances of a Retrofitted, Large-Scale, Biomass-Fired CHP Coupled to a Steam-Explosion Biomass Upgrading Plant, a Biorefinery Process and a High-Temperature Heat Network

This paper aims at assessing the impact of retrofitting an existing, 730 MWe, coal-fired power plant into a biomass-fired combined heat and power (CHP) plant on its energetic and exergetic performances. A comprehensive thermodynamic model of the power plant was developed and validated against field data, resulting in less than 1% deviation between the model and the measurements for the main process parameters. The validated model was then used to predict the behaviour of the biomass CHP after retrofitting. The modelled CHP unit is coupled to a steam-explosion biomass upgrading plant, a biorefinery process, and a high-temperature heat network. 13 scenarios were studied. At constant boiler load, delivering heat to the considered heat clients can increase the total energy efficiency of the plant from 44% (electricity only) to 64%, while the total exergy efficiency decreases from 39% to 35%. A total energy efficiency of 67% could be reached by lowering the network temperature from 120∘C to 70∘C. Identifying the needed heat clients could, however, represent a limiting factor to reach such high efficiencies. For a constant power demand, increasing the boiler load from 80 to 100% in order to provide additional heat makes the total energy efficiency increase from 43% to 55%, while the total exergy efficiency decreases from 39% to 36%.