Heat Delivery Research Articles

Edge intelligence enabled optimal scheduling with distributed price-responsive load for regenerative electric boilers

Heat supply accounts for a substantial amount of terminal energy usage. However, along with price rises in primary energy, there is an urgent need to reduce the average cost of energy consumption during the purchasing of thermal services. Electric heating, an electricity-fed heating production and delivery technology, has been suggested as a promising method for improving heating efficiency, due to the ease of scheduling. However, the traditional centralized operating methods of electricity purchasing rely on explicit physical modeling of every detail, and accurate future predictions, the implementation of which are rarely practical in reality. To facilitate model-free decisions in the field of electricity purchasing, heat storage, and supply management, aimed at cost saving in a real-time price environment, this study proposes a scheduling framework based on deep reinforcement learning (DRL) and the existence of responsive users. First, the structure of a distributed heating system fed by regenerative electric boilers (REBs), which facilitate shiftable heat-load control, is introduced. A terminal heat demand response model based on thermal sensation vote (TSV), characterizing the consumption flexibility of responsive users, is also proposed. Second, due to thermal system inertia, the sequential decision problem of electric heating load scheduling is transformed into a specific Markov decision process (MDP). Finally, the edge intelligence (EI) deployed on the demand side uses a twin delayed deterministic policy gradient (TD-3) algorithm to address the action space continuity of electric heating devices. The combination of a DRL strategy and the computing power of EI enables real-time optimal scheduling. Unlike the traditional method, the trained intelligent agent makes adaptive control strategies according to the currently observed state space, thus avoiding prediction uncertainty. The simulation results validate that the intelligent agent responds positively to changes in electricity prices and weather conditions, reducing electricity consumption costs while maintaining user comfort. The adaptability and generalization of the proposed approach to different conditions is also demonstrated.

Magnetically propelled chained nanocomposites for biologically relevant media exploration

Elongated nanostructures to be remotely and magnetically propelled in biologically relevant media, have gained attention as offering themselves as effective tools or carriers in theragnostics applications. However, the magnetic actuation associated remains challenging due to the lack of mechanical information in the media of interest, taking into account biophysical or biomedical purposes. In this study, we detail the magnetic actuation of magnetically propelled chained nanocomposites considering their dynamics, in which their velocity can be modulated in terms of the viscosity of the medium considered, given a magnetic field gradient. Simpler cases of distilled water, a water/glycerol mixture and a fluid made of cell extracts (imitating the cytosol of cells) of known viscosity are the basis experiments for the study of more complex media inside HeLa cells, murine NIH-3T3 fibroblasts and zebrafish larvae, offering the mechanical information required. The experimental results indicate that the magnetically propelled performance of the chained nanostructures can be precisely controlled in potentially changing scenarios, where drug and heat delivery, magnetic separation, or microfluidic technologies are demanded, using a magnetic field gradient and providing good estimations of the dynamical parameters involved.

Comparison of simulation and experimental test results of the turbocharger temperature for two gasoline direct injection engines

Understanding heat delivery in a multifaceted and vital engine component, such as the turbocharger, is important for improving engine performance and efficiency, but it is challenging to determine. In this paper, the temperature distribution in a turbocharger body was measured experimentally using a thermal camera, and a one-dimensional simulation of a turbocharger was developed for the temperature distribution. As part of the work, an innovative method is used to determine the thermal radiation constant of the turbocharger housing. In this method, the complete turbocharger system was first installed in a laboratory furnace and, at each stage, the temperature of the furnace was carefully adjusted. After temperature stabilization, a thermal image was taken with a thermal camera, and the radiation coefficient was obtained. Finally, a measurement of the temperature distribution was performed on the engine's test cell for the turbochargers of two three-cylinder gasoline engines (i.e. engines 1200 cc and 999 cc). The experiments include steady-state and transient tests. The transient tests include hot and cold tests at various operating conditions. The results showed that the maximum temperature of the turbine housing varies linearly with inlet gas temperature. Also, the axial distribution of the temperature in the compressor volute shows that temperature increases from the inlet side to the bearing housing side. Based on the numerical results, the maximum turbine housing temperature for engine 1200 cc is 679 °C and for engine 999 cc is 523 °C.

Pediatric Environmental Cold Injuries.

Cold weather injuries are relevant concerns for children during winter sports and outdoor activities. To mitigate the risk of cold injury in this high-risk population, providers can educate parents on proper outdoor attire as well as the added risks of wind and water exposure. There are 2 types of environmental cold injuries: freezing injuries and nonfreezing injuries. Frostbite is a freezing injury from direct contact with cold air or surfaces. The extent of injury depends on the depth to which the freezing extends. Treatment involves rewarming the frozen tissue with warm water baths and considering analgesia. Hypothermia is a nonfreezing cold injury, and it can occur even when ambient temperatures are above freezing. When there is a decrease in the body's core temperature, hypothermia progresses from mild to severe symptoms. Treatment of hypothermia is threefold but is also dependent on the core body temperature, as colder core temperatures will require more aggressive warming techniques. Hypothermia treatment involves passive protection from further heat loss (ie, removing wet clothing), which helps the body to warm itself. Treatment also involves active external rewarming wherein a heat source, such as a heated blanket, is used to increase body temperature. Active internal rewarming is the delivery of heat inside the patient's body, such as warmed intravenous fluids.

A comprehensive review and analysis on CO2 heat pump water heaters

• Existing CO 2 HPWHs in industrial and residential sectors are reviewed. • Performance restricted by the pinch point effect is analyzed. • Limitations in CO 2 compressors and lubrication are revealed for the first time. • Current enhancements to overcome the limitations are summarized. In the context of the Montreal Protocol, CO 2 is considered as an appropriate natural refrigerant with an Ozone Depletion Potential (ODP) of zero and a Global Warming Potential (GWP) of one. A CO 2 heat pump water heater (HPWH) can provide hot water with a relatively high COP and consume significantly less energy than all electric or gas water heaters. This study reviews and analyses the existing CO 2 HPWHs both in industrial and residential sectors, where the low-temperature and high-temperature systems are classified by the heat delivery temperature of below and above 80 °C, respectively. The significance and features of existing CO 2 HPWHs are also summarised in this study. Moreover, the performance limitations of current CO 2 HPWHs are discussed considering the temperature gliding matching, and the technical constraints in both CO 2 compressors and heat exchangers. Due to the drastic variation of CO 2 heat capacity with temperature and pressure, the heat exchange process between sCO 2 and water is affected by the pinch point. The temperature gliding matching can be enhanced by optimising the parameters in both the CO 2 and water sides, using zeotropic refrigerant mixtures, or adding new devices or cycles to the existing CO 2 system. Another way to improve the system performance is increasing the discharge pressure or discharge temperature, while current CO 2 reciprocating compressors have an upper-temperature limit of 140 °C and upper-pressure limit of 140 bar, as well as some constraints in the heat exchangers. Due to the decomposition risk of lubricant in the compressor, two types of oil-free compressors (turbo and scroll) have been described. But it is found that the turbo-compressor is hard to provide a competitive efficiency when the pressure is high, and there is a significant leakage flow in a scroll compressor.

축열식 연소산화장치 구현을 통한 VOCs 산화처리 및 폐열 회수 기술 개발

The reduction of greenhouse gases and Carbon Neutral (Carbon Zero) due to global warming is agreed by all countries around the world. The increase in global average temperature to climate change is kept within 2°C compared to before industrialization and achieved 1.5°C in the long run. Korea has set a 37% reduction target (315 million tons) compared to the 2030 emission forecast (851 million tons) and is promoting various air pollution reduction technologies and R&D policies to reduce greenhouse gases and minimize the impact on climate change.
 Currently, there are VOCs that are directly emitted into the atmosphere or that cause greenhouse gases as simple power generation and heat sources. Aromatic hydrocarbons such as benzene are strong carcinogens that cause leukaemia, central nervous disorder, chromosomal abnormalities, and hydrochloride can produce photochemical oxides by destruction of the ozone layer, global warming, and chain reactions of volatile organic compounds, causing eye irritation, reduced visibility, and damage to plants and crops.
 VOCs reduction technology should reduce the amount of harmful substances in advance by controlling operating conditions and working conditions. Technologies that can effectively process VOCs throughput of 95% or more are heat storage combustion systems and heat storage catalyst combustion systems.
 This paper proposes a heat delivery system specification design and emission concentration measurement technology for high-efficiency waste heat recovery of 100 CMM RTO (Regenerative Thermal Oxidation) device to reduce air pollution in VOCs generating sites. For the application of the waste heat recovery system, a 100CMM heat storage combustion oxidation system (RTO) is designed, and the performance is evaluated by measuring the concentration of VOC (Volatile Organic Compound) emissions according to production process operating conditions.

Impact of sector-coupling in microgrid to residual electricity demand properties

This paper discusses how the contribution of microgrid (MG) introduction to the power grid depends on sector coupling. MG is designed to suppress the residual demand from the grid and its variation, under the cost constraint. In this paper, three levels of sector coupling are considered for electricity, heat, and hydrogen demand. In Lv.1, the MG supplies only electricity to the demand. The MG is equipped with photovoltaic (PV) and storage battery. In Lv.2, the MG equipped with PV, storage battery, heat pump, chiller, thermal tank, and hydrogen gas boiler to supply both electricity and heat to demand. For heat delivery, heat pipeline network is laid and used. In Lv.3, all electricity, heat, and hydrogen supplies are coupled at MG. From the obtained results, it is ascertained that the higher sector coupling can realize the higher flexibility in residual demand.

POD-Kalman filtering for improving noninvasive 3D temperature monitoring in MR-guided hyperthermia.

BackgroundDuring resonance frequency (RF) hyperthermia treatment, the temperature of the tumor tissue is elevated to the range of 39–44°C. Accurate temperature monitoring is essential to guide treatments and ensure precise heat delivery and treatment quality. Magnetic resonance (MR) thermometry is currently the only clinical method to measure temperature noninvasively in a volume during treatment. However, several studies have shown that this approach is not always sufficiently accurate for thermal dosimetry in areas with motion, such as the pelvic region. Model‐based temperature estimation is a promising approach to correct and supplement 3D online temperature estimation in regions where MR thermometry is unreliable or cannot be measured. However, complete 3D temperature modeling of the pelvic region is too complex for online usage.PurposeThis study aimed to evaluate the use of proper orthogonal decomposition (POD) model reduction combined with Kalman filtering to improve temperature estimation using MR thermometry. Furthermore, we assessed the benefit of this method using data from hyperthermia treatment where there were limited and unreliable MR thermometry measurements.MethodsThe performance of POD–Kalman filtering was evaluated in several heating experiments and for data from patients treated for locally advanced cervical cancer. For each method, we evaluated the mean absolute error (MAE) concerning the temperature measurements acquired by the thermal probes, and we assessed the reproducibility and consistency using the standard deviation of error (SDE). Furthermore, three patient groups were defined according to susceptibility artifacts caused by the level of intestinal gas motion to assess if the POD–Kalman filtering could compensate for missing and unreliable MR thermometry measurements.ResultsFirst, we showed that this method is beneficial and reproducible in phantom experiments. Second, we demonstrated that the combined method improved the match between temperature prediction and temperature acquired by intraluminal thermometry for patients treated for locally advanced cervical cancer. Considering all patients, the POD–Kalman filter improved MAE by 43% (filtered MR thermometry = 1.29°C, POD–Kalman filtered temperature = 0.74°C). Moreover, the SDE was improved by 47% (filtered MR thermometry = 1.16°C, POD–Kalman filtered temperature = 0.61°C). Specifically, the POD–Kalman filter reduced the MAE by approximately 60% in patients whose MR thermometry was unreliable because of the great amount of susceptibilities caused by the high level of intestinal gas motion.ConclusionsWe showed that the POD–Kalman filter significantly improved the accuracy of temperature monitoring compared to MR thermometry in heating experiments and hyperthermia treatments. The results demonstrated that POD–Kalman filtering can improve thermal dosimetry during RF hyperthermia treatment, especially when MR thermometry is inaccurate.

Analysis of heat transfer characteristics and entransy evaluation of high viscosity fluid in a novel twisted tube

• A novel twisted tube is to improve the secondary flow distribution inside the tube. • Heat transfer performance and entransy evaluation are investigated numerically. • The novel twisted tube reduces the entransy dissipation compared with the plain tube. • Effects of geometry parameters and Reynolds number are analyzed comprehensively. The non-uniformity of the secondary flow distribution in the twisted oval tube has impeded its further improvement of the heat transfer performance. A novel twisted tube (NTT) improves the distribution of the secondary flow and enlarges the effect of the secondary flow on the main flow, intensifying the radial mixing and equalizing the temperature distribution of the fluid, which strengthens the convective heat delivery in the near wall region and the core zone comprehensively. Heat transfer characteristics and entransy evaluation of water and engine oil in the NTT are investigated in the low Reynolds number ( Re ) region. The heat delivery performance of the NTT improves with the reduction of the distance ratio ( DR ) and the twist pitch ratio ( PR ), and also raises with the increase of Re . The friction factor of the NTT increases with the reduction of DR and PR , and decreases with the rise of Re . Compared with the twisted oval tube, the NTT could elevate the Nusselt number and enlarge the friction factor by 1.49–1.56 times and 1.32–1.41 times, respectively. Compared with the plain tube, the NTT could improve the Nusselt number and increase the friction factor by 2.42–2.76 times and 1.48–1.56 times, respectively. The equivalent thermal resistance of the NTT decreases with the reduction of DR and PR and reduces with the increase of Re . The Case 4 with the minimum DR and the smallest PR shows the supreme heat transfer performance and the lowest equivalent thermal resistance. The NTT could reduce the entransy dissipation remarkably, compared with the plain tube, the NTT could decrease the equivalent thermal resistance by up to 58% for water under the condition of constant wall temperature and could reduce the equivalent thermal resistance by as much as 53% for engine oil under the condition of given heat flux on the tube wall.

Big data simulation for effective thermal conductivity modeling of thermosyphon

• Large number of simulation data over 36,000 cases for thermosyphon. • Development of simulation conditions based on 35 literatures. • Modeling the effective thermal conductivity up to 10,000 W/mK. • Correlation model for different lengths, ratios, diameters, and powers. • Utilization of the deep neural network to validate CFD data. Thermosyphon or thermosiphon has been continuously studied for various thermal engineering applications in terms of large heat delivery and removal. Their thermal resistances have been investigated as they are the key to infer the effective thermal conductivity in thermal systems. This study aims to provide an essential basis or modeling equation to design a thermal system to estimate the effective thermal conductivity with thermal resistance. Collecting big data using computational fluid dynamics is newly introduced to examine the thermosyphon, which cannot be tested in an experiment. More than 36,000 simulation cases are conducted by changing total length, radius, heat sink area, heater area, heat transfer coefficient at heat sink, and power of the heater. Selected cases cover the actual ranges by referring to existing experimental or numerical results in other literature. As a result of numerical analysis, a correlation between thermosyphon morphology, thermal resistance, and effective thermal conductivity is derived. The Deep Neural Network (DNN) is employed to validate the simulation data. It is confirmed that the results are consistent and verifiable. These results open a way as we can see that the effective thermal conductivity is a function of geometry and complex function of heat power or heat transfer coefficient. This correlation model is expected to play an essential role in designing thermal systems.

Abstract No. 338 Novel drug device combination for rectal carcinoma: rectal heating and intraarterial delivery of doxorubicin-loaded low temperature sensitive liposomes in a swine feasibility study

To establish a rectal hyperthermia (HT) model and evaluate plasma and tissue pharmacokinetics following systemic IV vs intra-arterial trans-catheter delivery of low temperature sensitive liposomes (LTSLs) loaded with doxorubicin during rectal HT

Abstract No. 351 Microneedle array platform with spatial control of heating and drug delivery profiles for experimental studies in small animals

Therapeutic strategies combining energy-based interventions and intratumoral immunotherapy are under investigation, however, the relationship between spatial energy-delivery profiles and bioeffects are not currently well understood. We are developing a microneedle array-based platform for experimental studies in small-animal tumor models investigating intratumoral immunotherapy in conjunction energy-based therapies. This abstract reports on the simulation-based characterization of spatially modulated thermal profiles achievable with the microneedle array.

The role of temperature-induced effects generated by plasmonic nanostructures on particle delivery and manipulation: a review

Abstract Plasmonic optical tweezers that stem from the need to trap and manipulate ever smaller particles using non-invasive optical forces, have made significant contributions to precise particle motion control at the nanoscale. In addition to the optical forces, other effects have been explored for particle manipulation. For instance, the plasmonic heat delivery mechanism generates micro- and nanoscale optothermal hydrodynamic effects, such as natural fluid convection, Marangoni fluid convection and thermophoretic effects that influence the motion of a wide range of particles from dielectric to biomolecules. In this review, a discussion of optothermal effects generated by heated plasmonic nanostructures is presented with a specific focus on applications to optical trapping and particle manipulation. It provides a discussion on the existing challenges of optothermal mechanisms generated by plasmonic optical tweezers and comments on their future opportunities in life sciences.

Global Status, Development and Prospects of Shallow and Deep Geothermal Energy

Geothermal heat pump systems (GHP), producing from shallow resources, are the spearhead of geothermal achievement and development. Global heat delivery grew exponentially to 600 PJ in 2020. GHP is the fastest growing segment in geothermal technology and one of the fastest growing application of renewable energy technologies worldwide. Other, various direct-use applications like space heating, bathing and swimming/wellness, industrial, agricultural (especially greenhouses) and aquacultural applications are based on deep, hydrothermal resources. These varieties produced worldwide 420 PJ heat in 2020; the average linear growth was, from 1995 on, about 10 % per year. It can be expected that this trend continues. Power generation, also from deep, hydrothermal resources, develops slowly but steadily, with an average growth-rate of 5 % per year, producing 95.0 TWh in 2020 in 30 countries. When comparing with other renewable power plant technologies (hydro, biomass, solar PV, wind), geothermal falls far behind – both in installed capacity (GWe) and in production (TWh). Only the annual availability of geothermal electricity is the highest among the renewables (60 %). Low geothermal productivity and growth-rate is due to extensive investments for solar PV and wind, which are by orders of magnitude higher than for geothermal power. The technology of Enhanced Geothermal Systems (EGS), based on deep, petrothermal resources, could be a game-changer. Requirements, problems and research goals to find solutions are presented.

Energy management optimization of integrated energy system with electric hydrogen hybrid energy storage

Abstract Integrated energy system (IES) has attracted wide attention as an efficient solution to a comprehensive utilization of hybrid energy system including electricity, heat, and hydrogen in recent years. This paper investigates the stochastic optimal operation for the micro integrated electric power, heat, and hydrogen delivery system. Firstly, the mathematical model of the micro integrated energy system for residential communities and other similar scenarios is discussed, including the energy interface, power microgrid, micro-heat system and micro-hydrogen system with considerations of distributed energy supply, energy storage, load, upstream energy network interface and their mathematical models. Secondly, the correlated uncertainty, such as wind power, solar power, and loads, are considered and handled in micro integrated energy system. Finally, a scenario-based approach is proposed for the stochastic operation of micro integrated energy system. The objective function is formulated to minimize the expected total operation and environmental costs, the hourly schedule of controllable components in micro integrated energy system. Numerical results demonstrated that the effectiveness of the proposed method. The correlated uncertainty and the corresponding impacts are accurately presented in the optimization model.

Tools for Network Smart City Management—The Case Study of Potential Possibility of Managing Energy and Associated Emissions in Metropolitan Areas

The article uses the case study of a polycentric metropolitan area as a starting point for a debate about the available tools for managing the network aspects of intelligent cities. We show that the construction of talents, the development of knowledge among officials and inhabitants, and technological tools such as Hubgrade (which allows for heat delivery process control, supervision, inspection, and results in emission reduction) are prerequisites for the sustainable development of cities. It is critical to understand that technological solutions are insufficient to accomplish such a task. Relevant stakeholders need to consciously take advantage of technological tools and build and utilise 4T potential and the self-learning capabilities of the organisations. An inherent feature of an organisation, such as a city, is cooperation between the people who build it. The main challenges of cities includes the reduction of pollutants resulting from the use of transport, heat sources, or energy production. In many cities, an efficient manner of reducing carbon dioxide emissions is to limit the consumption of thermal energy. In order to simultaneously maintain thermal comfort, in this situation, it is necessary to use intelligent technologies. The paper includes research related to the knowledge and development of 4T potentials (technology, trust, talent, tolerance) and to networking expansion by introducing the automated Hubgrade system, used in Warsaw district heating, into a similar metropolitan area. Along with an increase in the significance of relations, information, and knowledge as a key organisational resource, cities, as organisations, have become an important element of contemporary communities and organisations. They have the possibility of a positive climate change. The possibility of cooperation and networking between people forming an organisation is its inherent feature, such as in the Hubgrade project. Conclusions and recommendations are drawn for the analysed case—linking 4T potentials and the Hubgrade system—with the potential for future generalisations and extrapolations. The authors performed a simulation of possible energy savings and the reduction of harmful emissions in Metropolis GZM.

Hydrogen storage and heat transfer properties for large-capacity double thin-layered annulus ZrCo bed with secondary containment cavity

Fast heat and mass delivery with high cycling stability of the core component, hydrogen storage bed, in SDS are essential for the operation of the future tritium factory in ITER project. However, the aforementioned properties are still perplexing in large-capacity ZrCo bed, especially for that with secondary containment structure required by the actual tritium operation in the future. Herein, the performance including heating, cycling and cooling with two different size ZrCo beds (loading of ZrCo are 200 g and 2000 g respectively) were systematically studied. The experimental data shows that the maximum heating ability of the middle-size/full-scale storage bed are both about 10 °C/min, and the maximum hydrogen absorption capacity of these ZrCo beds are 44.6 L/405.5 L, respectively. Besides, hydrogen pressure and hydrogen retention during the following desorption can affect the cycling performance of the ZrCo bed. The use of transfer pump can reduce the pressure of the bed during the hydrogen desorption process (operated at 500 °C), which inhibits the disproportionation reaction of the ZrCo alloy. However, the degree of hydrogen pressure reduction in two the types of ZrCo bed are different. As a result, the cycling capacity of the middle-size bed (93.4%, lower hydrogen pressure) is higher than the full-scale bed (68.7%, higher hydrogen pressure) after 10 cycles. When the transfer pump was not used and operated at lower temperature (350 °C), the beds cannot release hydrogen completely, and partial hydrogen atoms are retained in the ZrCo alloy. The middle-size bed still maintains a hydrogen storage capacity of 94.5% after 10 cycles, while 75.9% of the hydrogen storage capacity remained for the full-scale bed. Therefore, the increase of hydrogen surplus in ZrCo alloy is helpful to improve its cycling stability. At last, the cooling performances of the beds under 10 different cooling methods were studied. Among the cooling methods, the best cooling rate was achieved by filling nitrogen in the secondary containment cavity and flowing water passing through the cooling circuit of the bed. This work will provide a crucial reference for the design and optimization of the subsequent operation technology of SDS in ITER. • Thin double-layered annulus ZrCo bed with secondary containment cavity is manufactured. • Real-time pumping transfer helps to improve the circulation stability of the ZrCo bed. • Keep remaining H in the ZrCo is benefits to improve its cycling stability.

Ice front retreat reconfigures meltwater-driven gyres modulating ocean heat delivery to an Antarctic ice shelf

Pine Island Ice Shelf (PIIS) buttresses the Pine Island Glacier, the key contributor to sea-level rise. PIIS has thinned owing to ocean-driven melting, and its calving front has retreated, leading to buttressing loss. PIIS melting depends primarily on the thermocline variability in its front. Furthermore, local ocean circulation shifts adjust heat transport within Pine Island Bay (PIB), yet oceanic processes underlying the ice front retreat remain unclear. Here, we report a PIB double-gyre that moves with the PIIS calving front and hypothesise that it controls ocean heat input towards PIIS. Glacial melt generates cyclonic and anticyclonic gyres near and off PIIS, and meltwater outflows converge into the anticyclonic gyre with a deep-convex-downward thermocline. The double-gyre migrated eastward as the calving front retreated, placing the anticyclonic gyre over a shallow seafloor ridge, reducing the ocean heat input towards PIIS. Reconfigurations of meltwater-driven gyres associated with moving ice boundaries might be crucial in modulating ocean heat delivery to glacial ice.

A water-heat combined supply system based on waste heat from a coastal nuclear power plant in northern China

• A new water-heat combined supply system based on waste heat is proposed. • The system realizes the simultaneous delivery of water and heat. • The heating and water supply costs are 34.27 ¥/GJ and 4.08 ¥/m 3 , respectively. • The system has a higher exergy efficiency and a better economic benefit. Based on the existing waste heat recovery technology and seawater desalination technology, a water-heat combined supply system based on waste heat from a costal nuclear power plant is proposed. The proposed system can improve the heating capacity of district heating systems and reduce the energy consumption of water-generating seawater reverse osmosis systems by recovering the waste heat from exhaust steam in a nuclear power plant. Through the simultaneous delivery of water and heat, the long-distance conveyance cost is reduced. The thermodynamic characteristics, energy-saving properties, environmental benefits, and economic efficiency of the proposed system are discussed and analysed. The results show that the heating capacity of the proposed system is increased by 55.5% compared to the original extraction steam heating load. The exergy efficiency is 16.07% higher and the heating cost is 12.32 ¥/GJ lower than those of traditional cogeneration district heating systems. The water supply cost of the proposed system is 2.95 ¥/m 3 lower than that of the conventional desalination water supply system. The current results of this study will be helpful in solving problems related to heat and water resource shortages and the high costs of long-distance heat and water conveyance in coastal areas.

Solar-driven interfacial evaporation of a hanging liquid marble

A liquid marble is a droplet coated with hydrophobic particles. Due to the large capillary energy associated with particle adsorption, this particle-armed liquid normally sustains long-term stability rather than evaporation under ambient condition. Conversely, we show here experimentally that liquid marbles coating with photothermal nanoparticles can significantly accelerate the liquid evaporation under solar irradiation. A series of experiment in solar evaporation of water drops, nanofluid drops as well as liquid marbles are conducted under controlled condition to verify this concept. It is found that the liquid marble exhibits the highest evaporation rate among the three cases. This high performance is attributed to the plasmon-coupling effect between neighboring nanoparticles along the drop surface, creating a high-temperature thermal boundary for intense evaporation of the interfacial liquid. While solar evaporation of nanofluid induces multiple scattering events among the nanoparticles that increases photon absorption within the drop domain, resulting in a collective heating to enhance the evaporation. Numerical modelling is further introduced to disclose the temperature distribution in these photothermic systems. Despite its diffusion nature, the temperature distribution can be engineered highly non-uniform and concentrated at the nanoscale using the particle assemblies in close proximity. A significant degree of nanoscale control over the individual temperatures of neighboring particles is demonstrated, depending on the interparticle gaps and dielectric surrounding media. Our findings open new possibilities for flexible control of photothermal processes and precisely heat delivery for solar vapor generation or local welding of textured nanomaterial.