Heat Integration Research Articles

Long-wavelength infrared metamaterial absorber with polarization and angle insensitivity using compact hybrid cylindrical structures.

Broadband metamaterial absorbers in the long wavelength infrared region are promising in applications including thermal imaging, cloaking, radiative cooling and IR signature suppression. Although high absorption over the long wavelength infrared region has been extensively achieved, the challenge is to shrink both the thickness and lateral footprint of unit absorbing structures. Here, a compact broadband long wavelength infrared metamaterial absorber consisting of multilayered Ge/Ti/Ge/SiO2 hybrid cylindrical structures, whose period and thickness are only ∼1.2 μm, is proposed and realized. Various surface plasmon polaritons, localized surface plasmon resonances and their hybridization modes in the long wavelength infrared region, with polarization and angle insensitivity (in the range of 0-45°), are supported by this compact absorber whose absorbing unit is ultra-thin with a small footprint, thanks to the strong redshift effect induced by high-k Ge. Paired with the loss provided by Ti and SiO2, an experimental spectral averaged absorption of 92.7% is achieved over 8 to 14 μm, agreeing well with simulation. The absorber can be facilely fabricated by a standard photolithographic process, not requiring lengthy and costly e-beam lithography. The absorber is promising in IR signature suppression indicated by preliminary results. The structural compactness and excellent long wavelength infrared absorbing capability grant the presented absorber good potential in various applications, especially those requiring miniaturization, integration and low heat capacity.

Energy Optimization of Dimethyl Ether (DME) Production Process from Methanol Dehydration

The increasing demand for sustainable and clean alternative fuels has driven the focus on dimethyl ether (DME), an environmentally friendly and non-toxic chemical with high potential as a fuel and industrial solvent. DME can be produced from various raw materials such as natural gas, methanol, biomass, and coal. This study investigates the optimization of DME production from methanol dehydration using a fixed-bed plug flow reactor and γ-Al₂O₃ catalyst, emphasizing energy efficiency improvements. Modifications were implemented in the Aspen HYSYS simulation by replacing the conventional heater with heat exchanger and utilizing heat generated during cooling process for another heating process. The results demonstrated a significant reduction 65.8 % in net energy consumption from 8.54×106 kJ/h to 2.92×106 kJ/h, validating the effectiveness of these modifications by leveraging Aspen HYSYS simulations, the proposed design achieved high process efficiency while maintaining the target DME purity of 99.95 % produced. This research highlights the potential of heat integration strategies to enhance the economic and environmental performance of DME production processes. Copyright © 2024 by Authors, Published by Universitas Diponegoro and BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Nuclear power plant waste heat opens a window of next-generation desalination hybridization: a SOAR-based review.

This review examines the potential for utilizing nuclear power plant (NPP) waste heat in hybrid desalination systems, focusing on Reverse Osmosis-Low-Temperature Evaporation (RO-LTE) driven by renewable energy sources and atomic waste heat. By employing a SOAR (Strengths, Opportunities, Aspirations, Results) analysis, the study evaluates the integration of NPP waste heat into various desalination technologies, emphasizing the environmental benefits and energy efficiency improvements. Fundamental aspirations include advancements in material science and heat exchanger designs, which enhance heat transfer and evaporation processes. The review also explores cost reduction strategies, such as integrating hydrogen production and mineral recovery from desalination by-products. Passive technologies and process optimization are proposed to minimize operational costs and energy consumption, supporting long-term sustainability. This review serves as a resource for decision-makers, offering insights into the strategic use of NPP waste heat in desalination to address water scarcity while promoting energy efficiency and sustainability.

Membrane-cryogenic hybrid CO2 capture—A review

The membrane-cryogenic hybrid process is a promising CO2 capture process, which combines the advantages of membrane and cryogenic, such as high efficiency (up to 98 % CO2 captured) and low energy consumption (specific energy consumption around 1.7 MJ/kg CO2 avoided). Through pretreatment by membranes, CO2 concentration can be increased, which makes it possible to separate CO2 via phase change in the cryogenic unit. This work reviews the current status of the development of membrane-cryogenic hybrid processes. The synergy between membrane and cryogenic separation is summarized to identify the bottleneck of such processes and provide insights for process improvement. It was found that cold temperatures would be beneficial to reduce CO2 activation energy and then improve CO2 selectivity of membranes. To further improve the CO2 separation performance, the potential intensification methods of the membrane-cryogenic hybrid process including cold-membrane synthesis, process optimization via heat integration are discussed and envisioned.

Enhancing third-generation district heating networks with data centre waste heat recovery: analysis of a case study in Italy

In this study, the integration of waste heat from a Data Centre (DC) into a Third-Generation District Heating Network (DHN) is evaluated, showing the improvement in the environmental footprint of the DHN currently supplied by fossil fuels (combined heat and power devices fuelled by natural gas). DC serves as a source of low-grade thermal waste heat, which is upgraded to the required temperature for the DHN using high-temperature heat pumps. Energy analyses are conducted on an hourly basis, considering load profiles of the DHN derived from a real case study and varying thermal loads of the DC (100–500 kW). The key findings of the research are as follows: a non-integrated 100 kW DC produces 926 MWh/year of waste heat which is discharged into the surrounding environment (contributing to the urban heat island effect), in the integrated scenario the proportion of waste heat in the DHN energy mix ranges from 12 % to 59 % resulting in a reduction of gas consumption ranging from 11 % to 58 %. These results underscore the significant potential for energy savings and reduced fossil fuel consumption through the utilisation of waste heat from DCs in DHNs, enhancing the widespread decarbonisation of this sector.

Advanced exergy analysis of a novel mass integration cogeneration system driven by geothermal energy

To mitigate fossil energy consumption and increase renewable energy use, a novel mass integration cogeneration system (MICS) driven by geothermal energy is proposed in this work. Parametric evaluations are conducted in order to ascertain crucial system parameters. The system is analyzed thermodynamically utilizing exergy analysis and advanced exergy analysis. The findings indicate a direct relationship between the refrigeration coefficient of performance and the power generation efficiency, as well as the mass flow rate of the working fluid, the turbine input pressure, the valve outlet pressure, and the mass fraction of the working fluid at the generator outlet. Exergy analysis reveals that the exergy efficiency of the MICS is greater than 0.85. The condenser exhibits the highest exergy destruction, amounting to 54.52 kW. Given that around 40 % of exergy destruction in power consumption devices (such as turbines, compressors, and pumps) is preventable, there is significant potential for improvement. Furthermore, the MICS employs 50 % less working fluid compared to a heat integration cogeneration system. The implementation of advanced exergy analysis in this study will facilitate the progress of geothermal energy utilization systems, while the investigation of optimization possibilities will assist in their practical deployment in the industry.

Passive Haptic Gloves with Embedded Sensors for Immersive Virtual Reality Training

Considering the increasing demand for the integration of haptic feedback into virtual reality (VR) devices, we studied and developed a multi-sensor and actuator array for real-time perception in virtual reality for training first responders. The sensors respond to users’ interactions in the VR world and actuate the response in the real world to create realistic sensory perception [1–2]. Though several haptic device applications have been created [3], very few of them have investigated the integration of an all-in-one sensory feedback mechanism. This paper presents a novel haptic feedback glove that helps with virtual reality training applications by utilizing all-in-one sensory feedback of heat, and cold. We investigated heat and cold sensing by incorporating peltiers and microheaters into the multi-functional haptic glove to generate the radiation of heat and cold. This version of the glove functions on three components: a microcontroller (ESP32), thermocouple modules that work as sensor elements (-55°C to 125°C), polyimide heater plate films, and micro Peltiers (12V max at 12W max) that work as actuators. These three modules are responsible for creating thermal haptic feedback, which communicates with the virtual environment world and the local environment to create the sensation of heat and cold, as shown in Fig. 1(a). When the user touches a hot or cold object in virtual reality, the hand tracking recognizes the element triggering the actuators, which are controlled by the sensor to regulate the temperature. We utilized Unreal Engine 5 (UE5) and two frameworks to enable serial and Bluetooth data communication between UE5 and the microcontroller for the high-risk training simulation. Based on Fig. 2 (a), after carefully testing, the distance between the data transfer start and maximum temperature output was about a full arm’s length in real life. This could be translated to 2 to 3 feet in distance. In the case of Fig. 2(b), we see multiple negative voltages applied to the Peltier device, producing the following equation:(1).In eq.1, A is the ambient temperature, T is the temperature of the object, D is the max distance of when the user starts feeling the object’s temperature, and t is the temperature of the finger because each Peltier is individually controlled. The heating ramping rate was 4 seconds from room temperature to 60°C and for cooling, the ramping time was 8 seconds from room temperature to 10°C. The currently developed glove demonstrates for the first time the integration of heat and cold sensing for VR applications. The developed prototype glove will be used for implementing training in VR for safety officers, military, and first responders. Figure 1

Eco-efficiency analysis and intensification of the monochlorobenzene separation process through vapor recompression strategy

Monochlorobenzene is widely used in producing herbicides, pesticides, and pharmaceuticals and, despite its toxicity and lack of a green substitute, has significant commercial influence. Thus, process intensification can enhance the purification process's sustainability performance. Recently, a double-effect distillation with heat integration (DEDHI) scheme was proposed to intensify an industrial-scale monochlorobenzene separation plant. As a continuation, this work proposes another strategy based on heat integration and vapor recompression (VRHI). A utility plant was considered for realistic outcomes regarding water consumption, CO2 emissions, and utility costs, grouped to represent the process's eco-efficiency. The total annualized cost (TAC) criterion was also contemplated. The comparison showed that DEDHI and VRHI are 84.57 % and 96.21 % more eco-efficient than the conventional process, respectively. The DEDHI design is more economically attractive, reducing TAC by 21.40 % for a 3-year payback period. In contrast, the VRHI scheme is more environmentally friendly, reducing CO2 emissions and water consumption by 73.32 % / 94.08 % (United States / Brazil locations) and 84.87 %, respectively. However, VRHI is only economically attractive for a 10-year payback period, with TAC savings of 18.10 % compared to the conventional process, mainly due to the high capital expenditure for the two-stage compressor and the electricity cost.

Comparison of different heat integration pressure swing distillation processes for separating isobutanol and p-xylene azeotrope

Chemical process intensification has attracted extensive interest of scholars. Distillation, as a high energy consumption industry, is in urgent need of energy saving and CO2 emissions reduction by means of process intensification. In this paper, isobutanol and p-xylene azeotrope was separated by pressure swing distillation (PSD). Combined with process integration method, four heat integration PSD processes including partial heat integration PSD (PHI-PSD), enhanced partial heat integration PSD (EPHI-PSD), full heat integration PSD (FHI-PSD), and enhanced full heat integration PSD (EFHI-PSD) were designed and optimized through sequential iterative procedure. The total annual cost (TAC), CO2 emissions, and thermodynamic efficiency were calculated and compared. By comparing relevant data, it is found that EPHI-PSD process has obvious advantages in terms of economic, thermodynamic efficiency, and environmental benefits. Specifically, comparing with the basic PSD process, thermodynamic efficiency of EPHI-PSD process is improved by 97.8% while TAC and CO2 emissions are decreased by 37.0% and 50.1%, respectively.

Energy-saving separation of isobutanol/ethanol/water by extractive distillation with deep eutectic solvents

To recycle isobutanol and ethanol from wastewater, different extractive distillation flowsheets with different entrainers are proposed. Firstly, the entrainers glycerol (GI), ethylene glycol (EG) and different deep eutectic solvents (DESs) are compared from the perspective of relative volatility and quantum chemical calculation. Subsequently, the indirect extractive distillation (IED) process and direct extractive distillation (DED) process with ChCl/GI(1:2) or EG as entrainer are studied and optimized using the NSGA-II method. Moreover, heat integration is utilized to optimize energy efficiency. The results reveal that the ChCl/GI(1:2) processes are more environmentally friendly and economical than EG processes. The heat integrated indirect extractive distillation process (IED) with ChCl/GI(1:2) entrainer demonstrates the most promising process, with a reduction of 35.93% in TAC and 34.89% in CO2 emissions compared to the IED-EG process.

Energy-saving research on the separation of isopropyl acetate and isopropanol azeotrope using pressure-swing distillation based on phase equilibrium

In high purity thioglycolic acid production, isopropyl acetate is used to extract the acid from intermediates, but it hydrolyzes and forms azeotrope with isopropanol under acidic conditions. To achieve environmental conservation, resource utilization, and clean production goals, the design of economically profitable separation processes becomes imperative. Pressure-swing distillation (PSD) with process intensification is employed after derived binary interaction parameters from VLE data at lower pressures, and sequential iteration simplified optimization is performed. Further to overcome the high energy consumption encountered in traditional PSD, heat integration and steam recompression technology were incorporated, resulting in four energy-saving PSD designs. And temperature-enthalpy diagrams were utilized to assess their energy consumption. Based on evaluation indicators of total annual cost (TAC), total energy consumption (TEC), and CO2 emissions, all improved PSD processes significantly reduced TAC and CO2 emissions. Among them, heat pump (HP-PSD) demonstrating the highest economy and eco-friendliness with a 30.1 % and 82.4 % reduction in TAC and CO2 emissions. Heat pump assisted heat integration (HP-HIPSD) also attracted significant attention of reducing TAC by 16.3 %. A longer payback period is expected to yield higher cost savings from all enhanced designs. This study provides invaluable insights for the separation and sustainable development of alcohol ester azeotropes.

Separation for diethoxymethane/ethanol/water by a thermally coupled extractive pressure swing distillation process with mixed solvent

A sustainable and efficient process for separating diethoxymethane/ethanol/water azeotropic systems was proposed via a mixed solvent as an entrainer and thermal coupling technology to enhance the extractive distillation process. The microscopic mechanisms between different molecules were precisely explored through molecular simulation technology, and suitable candidate entrainers were determined. On this basis, extractive distillation processes using different solvents as entrainer were further designed. The operation parameters of the process were improved by multi-objective optimization. The extractive distillation process coupled with heat pump and heat integration technology was further brought in based on the optimal solvent extractive distillation process. The results indicate that the intensification process reduces the total annual cost by 3.14% and gas emissions by 29.02% compared to the basic process. This study not only provides a new idea for the design of extractive distillation process, but more importantly, it provides a reference for the screening and industrial application of mixed entrainer.

Sizing large-scale industrial heat pump for heat recovery from treated municipal sewage in coal-fired district heating system

Electrification of district heating and deep integration of sectors of national economies are fundamental elements of the future smart energy systems. This paper discusses the problem of optimal sizing of large-scale high-temperature heat pumps using treated sewage water as a heat source in a coal-fired district heating system. The study presents an approach to modelling of heat pump system that enables techno-economic analysis for investment decision making. Such analysis is enabled by a black-box-type identification model of the selected industrial heat pump. The model was developed based on the data generated by physical modelling of the heat pump using Ebsilon Professional software. In addition, it is proposed that the heat pump system is integrated with a dedicated photovoltaic power plant. The case study takes into consideration site-specific technical, economic, ecological, and legal constraints, weather conditions, hydraulic performance of the heat-ing network, and variability of loads within the sewage and the district heating systems. The results revealed that the proposed modelling approach is effective regarding multiple simulations and system optimisation. In addition, it was found that large-scale heat pump projects can be technically feasible and profitable if the heat pump is appropriately sized and operated. In the given case, the optimum size of the heat pump for a city of around 180 000 inhabitants is around 12 MW under maximum winter load.

Optimizing energy consumption in post-combustion CO2 capture at an NGCC power plant: a simulation-based approach

Abstract This study aims to optimize energy consumption in post-combustion carbon capture processes at a Natural Gas Combined Cycle (NGCC) power plant. It further addresses challenges associated with steam extraction from NGCC power plants and explores non-condensable steam turbines to boost process efficiency. Various scenarios are explored to minimize energy requirements by leveraging heat integration and alternative solvent compositions. The research uses simulations with commercially available software and literature-derived data to address the challenges of high energy consumption in such processes. Emphasis is placed on optimizing solvent composition and implementing advanced heat optimization strategies to reduce energy consumption. Four scenarios with different solvent compositions are investigated, utilizing Monoethanolamine and aqueous piperazine. The results show that process parameter optimization and heat optimization strategies can result in significant energy savings. To attain a carbon-neutral energy landscape, this research helps develop more sustainable and effective carbon capture methods.

Multi-objective optimization and performance evaluation for the recovery of isopropanol and benzene from effluent via side-stream extractive distillation with intermediate reboiler processes

Side-stream extractive distillation typically requires the introduction of expensive high-pressure steam, which is not conducive to economic benefits. A heuristic approach is to introduce an intermediate reboiler in side-stream extractive distillation to reduce the use of high-pressure steam and thus lower economic costs. In this article, three side-stream extractive distillation with intermediate reboiler processes are proposed to recover the benzene and isopropanol from chloramphenicol production effluent. Taking into account economic, environmental, and entropy production indicators, an evolutional genetic algorithm is used to conduct the multi-objective optimization for the three processes. After obtaining the optimal operation parameters, the corresponding heat integration processes are proposed. Following that, the six process are compared to the optimal double side-stream extractive distillation process (D-SSED) in literature. It indicates that all six processes have good economic potential, especially the single side-stream extractive distillation with intermediate reboiler process with heat integration (S-SSEDIR-2-HI), which is the optimal scheme. Compared to the D-SSED process, it can reduce total annual cost (TAC) by 29.02 %, CO2 emission by 36.14 %, and entropy production by 44.07 %.

Analysis of energy, water, land and cost implications of zero and minimal liquid discharge desalination technologies

Desalination is increasingly essential to ensure access to water as climate change and population growth stress fresh water supplies. Already in use in water-stressed regions around the world, desalination generates fresh water from salty sources, and in doing so forms a concentrated brine that requires disposal. There is a growing push for the adoption of zero/minimal liquid discharge (ZLD/MLD) technologies that recover additional water from this brine, thereby reducing the liquid volumes requiring disposal. In this analysis, we evaluated the cost, energy and sustainability impacts of 7 overarching treatment trains with 75 different configurations. We found ZLD/MLD water recoveries ranging from 32.6% to 98.6%, but with steep energy and cost trade-offs that underscore the crucial roles of ion-specific separations, heat integration and clean energy sources. We explored the key trade-offs between cost, energy and water recovery, elucidating the increasingly tight connections that are central to the energy–water nexus and desalination.

SekQuaSens 3 : sector integration heat, electricity and mobility demand in a district

SekQuaSens ³ : sector integration heat, electricity and mobility demand in a district

Evaluation of AlN insertion layer on the properties of heterogeneous integrated Ga2O3 films on sapphire

Integration of gallium oxide (Ga2O3) with highly thermal conductive AlN/sapphire substrate is more effective to dissipate heat in the Ga2O3-based devices. In this work, the properties of Ga2O3 films grown on sapphire and AlN/sapphire substrates via MOCVD were both examined via various experimental methods. The X-ray diffraction (XRD) analysis showed good crystallinity and different orientations of Ga2O3 and AlN thin films. The absorption properties and band gaps were extracted from UV/Vis spectra. The atomic force microscopy (AFM) scanning images showed smooth Ga2O3 surfaces on sapphire and AlN/sapphire substrates (RMSs of 2.4 nm and 4.8 nm, respectively). The scanning electron microscopy (SEM) highlighted well-defined grains of Ga2O3 and distinct boundaries of both heterostructures. X-ray photoelectron spectroscopy (XPS) analysis depicted the distributions of various components throughout the films. Finally, by using the time-domain thermoreflectance (TDTR) method, the thermal conductivity and the thermal boundary conductivity of Ga2O3 without AlN interlayer were found to be 3.1 W/(m·K) and 70.1 MW/(m2·K) respectively. By comparison, adding AlN interlayer made the thermal conductivity and thermal boundary conductivity rise to 3.3 W/(m·K) and 111.5 MW/(m2·K) respectively. These findings have demonstrated the high-quality Ga2O3/AlN integration and good heat dissipation provided by AlN interlayer, opening up new prospects for Ga2O3/AlN devices in the future.

Heat Pump-Assisted Extractive Pressure-Swing Distillation with Integrated Feed Preconcentration/Solvent Recovery for Isopropanol-Benzene-Water Separation

Recently, heat-integrated pressure-swing distillation (HIPSD) has been explored for recovering isopropanol and benzene from wastewater, but the process remains highly energy-intensive. Given the dilute nature of the feed, intensified extractive distillation with an integrated preconcentration column (IED) is more suitable. However, previous researches have often overlooked the critical role of pressure and lacked rigorous optimization of operating pressure in such systems. In this article, we developed novel extractive pressure-swing distillation with integrated feed preconcentration/solvent recovery column (IEPSD) by introducing a pressure-swing configuration and incorporate energy-saving technologies to achieve more sustainable and cost-effective separation processes. First, thermodynamic analysis is conducted to explore the effect of pressure on extractive pressure-swing distillation. Then, a parallel genetic algorithm is applied for rigorous optimization, followed by the application of heat integration and heat pump. The IEPSD is superior to IED in terms of total annual cost (TAC) and CO2 emission. With the inclusion of energy-saving technologies, IEDHI and IEPSDHI further reduced TAC by 5.29% and 7.40%, and cut CO2 emissions by 25.18% and 24.03%, respectively, compared to their base processes. The use of a heat pump is particularly advantageous for IEPSD due to its lower boiling temperatures under vacuum pressure, leading to the development of IEPSDHIHP, which offered an additional 22.36% CO2 reduction and marginally lower TAC than IEPSDHI. Ultimately, IEPSDHIHP proves to be the best option, offering a 51.15% TAC reduction and 68.42% CO2 emissions reduction compared to HIPSD. In summary, the developed IED and IEPSD processes, especially with heat integration and heat pump technologies, offer significant economic and environmental advantages over conventional HIPSD.

Combining energy generation and radiant systems: Challenges and possibilities for plus energy buildings

Radiant heating and cooling (RHC) systems are being more widely adopted considering the well-known technical advantages: increased thermal comfort, space saving, and reduced energy use. Since the building sector is currently one of the largest consumers of fossil fuels, many directives and regulations have been enacted to address the intense concern about energy use for space conditioning.Even though radiant systems are considered as an energy efficient technology for building heating and cooling, more effort is needed to fulfil the zero energy requirements outlined by recent standards and directives. Renewable Energy Sources (RES) are an effective solution to avoid using finite fossil fuels and related geopolitical issues enhanced by the recent world conflicts. Despite being primarily intermittent and subject to economic and regional constraints, RES offer suitable temperature levels to supply low temperature heating and high temperature cooling operation, a major advantage of RHC system.Although a limited number of studies directly report energy savings or CO2 emission reduction as the main outcomes of the research related to this combination, valuable insights have been obtained for the present review. Primary energy can decrease between 40% and 80% with different integration of RHC, photovoltaic, heat pumps and district heating. TABS can lead to load shifting up to 100%, allowing an increased self −consumption of renewable energy.This paper provides evidence on whether coupling radiant systems with renewables is a promising strategy for achieving nearly-zero annual energy balances in building stocks. It investigates recent trends, limitations and potential to support decarbonization goals.