In this study, the effects of employing aluminum additive particles in an unconsolidated adsorbent bed on an adsorption cooling system (ACS) performance are studied. A three-dimensional distributed-parameter model is developed to investigate whether there is an optimum additive volume fraction for different bed conditions of a finned flat-tube heat exchanger filled with silica gel SWS-1L. Moreover

Ejectors usually act as thermal compressors to recover the superfluous water vapor in multi-effect desalination systems. However, the influences of wall conditions on the steam ejector performances were not fully understood. To investigate the effects of the surface roughness and temperature on non-equilibrium condensation and entrainment performance in the steam ejector, a wet steam model was built

Temperature polarization is a crucial issue in the application of the membrane distillation technique, as it can significantly affect its entire performance. Experimental and numerical studies were conducted to decrease the temperature polarization in the feed and permeate channels by reducing the channel height. This is the first time that a study addresses the temperature polarization in membrane

In variable refrigerant flow (VRF) systems with multiple indoor units, individual energy metering (IEM) not only contributes to a fair charge for the tenants, thus avoiding their complaints on the charging fee, but also shows the actual allocation of capacity for IUs. However, it is extremely challenging to measure the accurate capacity of each IU directly according to current researches though total

This study investigates time-dependent heat transfer with periodic excitation in micro-scale systems. Specifically, this study sheds light on time and length scales relevant to periodic heat transfer in micro systems. First, a system's substrate is modeled as a slab of finite thickness, in which the heat conduction equation is solved analytically for a periodic temperature boundary condition over the

A channel layout of a flat-plate micro pulsating heat pipe (MPHP) for an excessively localized heating condition is proposed. The excessively localized heating condition is implemented using a small heater, which covers only about 2% of the whole area, in the middle of the bottom part. To simplify the heat transfer characteristics in MPHPs, the channel regions are modeled as a region with the high

In this paper, the performance and economic analysis of a heat pump water heater assisted regenerative solar still using latent heat storage was experimentally studied. The heat released during condensation of water vapour inside the solar still was regenerated using a heat pump to pre-heat the saline water before entering the basin and producing hot water for domestic use. The experimental observations

Heat pumps are gaining interest to replace fossil fuel burners with the increase of the share of renewable sources in the electricity generation mix. Moreover, low global warming potential (GWP) alternatives offer a more environmentally friendly option as refrigerants. HFO-1234ze(E) and its non-flammable mixture R-515B are experimentally investigated for the first time to replace HFC-134a in heat pump

In order to enhance the performance of the automobile waste heat recovery system, a novel two-stage automobile thermoelectric generator with a cascade configuration along the temperature gradient of exhaust gas was designed. The corresponding integrated one-dimensional numerical model considering temperature-dependent thermoelectric materials was developed to predict the performance accurately. The

Convective heat transfer performances of dilute metal oxide suspensions in D.I water (Deionized water) flowing through a VUV (Vacuum Ultraviolet) surface tuned mini channel with a hydraulic diameter of 3 mm were quantified in this work. The experiment was carried out first on a channel with untreated PDMS coating with a contact angle of 86.2 ± 2.7° and then with a VUV treated PDMS channel having a

Inhalation gas humidification is a kind of major matter for patients using mechanical ventilation systems due to the necessity of keeping mucus layer at the suitable thickness and wetness. The performance of membrane humidifier with partially blocked gas channels, is investigated in this study. Three types of membrane humidifier channel arrangement, including a normal, wet channel with obstacles, and

The minimum film boiling temperature (Tmin) is one of the primary factors that influence the efficiency of rewetting of nuclear fuel rods after a loss-of-coolant accident (LOCA) in a light water reactor. In order to properly study the mechanisms behind the transient heat transfer phenomena that occurs during quenching, experimentation must be done using the most high-fidelity, high-resolution instrumentation

Climate change mitigation requires developing low-carbon technologies capable of achieving CO2 emission reductions at the gigatonne scale and affordable cost. Biomass gasification, coupled with carbon capture and storage, offers a direction to atmospheric CO2 removal. To compensate for the issues associate with the high-investment requirement of CO2 removal unit and lower efficiency compared to fossil-based

The condensation of moist air plays an important role in daily life and industry. During the condensation process, single-phase and phase-change heat transfers occur simultaneously. A three-dimensional finned tube is an effective element for enhancing heat transfer. However, the latent and sensible heat transfer during moist air condensation outside a three-dimensional finned tube has not been experimentally

The membrane-based desorber is considered a promising alternative to miniaturize the present generator in the absorption refrigeration system, owing to its large specific interfacial area, which is expected to reduce the required volume for the unit of cooling capacity of the system. The heat and mass transfer characteristics of a desorber consisting of a porous polytetrafluoroethylene hollow fiber

The influence of inlet placement and distributor geometry on the steady-state efficiency and pressure drop of cryogenic plate-fin heat exchangers (PFHEs) is studied using a three-dimensional simulation model. The simulation model employs a porous media approach to combine computational fluid dynamics with well-established correlations for heat transfer and pressure drop in fin materials. An isothermal

The operational flexibility of coal-fired power plant is very important for the integration of large-scale renewable energy to the grid. In order to increase the operational flexibility of coal-fired power plant, a 600 MW subcritical coal-fired power plant was selected as research example to analyze the influence of steam extraction parameters and operation load by simulation. A novel main steam extraction

Convective drying is one of the most energy intensive thermal processes. In convective textile drying, >50%) of the input energy is typically lost to the surroundings. A transient, two-dimensional mathematical model of textile drying in a gas-fired tumble dryer was developed. Mass, momentum, and energy conservation were used to understand the heat and mass transfer phenomena occurring in and around

This article presents a solution to the geothermal problem of transient heat production from hot dry rocks using a horizontal well. Dimensionless forms of the governing equations are derived, including conduction in the rock, convection between the wellbore rock and the fluid, and advection and conduction in the fluid along the well. Ten model material and geometric parameters are reduced to three

In this study, an analytical solution of a porous fin with natural convection and radiation heat transfer is carried out. For the first time, the analysis is accomplished in Local Thermal Non-Equilibrium (LTNE) model. The investigation is carried out on a porous fin with finite length and adiabatic tip. The Darcy model and Boussinesq approximation for buoyancy effects are used to evaluate the infiltration

A continuing research on the direct expansion solar assisted ejector-compression heat pump cycle for water heater is presented in this paper, aiming to reveal the system dynamic characteristic by experimental method. The performance advantage of the presented system is verified at first. According to the test results, under the considered condition, the presented system can outperform the traditional

Due to the simplicity of the exhaust gas aftertreatment system, the heavy-duty natural gas spark ignition(SI) engines play an important role in achieving the macro targets of the reduction of petroleum consumption, carbon and harmful emissions. Considering that power-to-methanol is economically more feasible than power-to-methane, methanol is proposed to continue the advantages of natural gas engines

Thermal management is crucial for the lifespan and safety of lithium-ion batteries, especially for the electrochemical energy storage which is composed of thousands of battery cells. In this paper, a novel battery thermal management system (BTMS) with internal finned structure was first proposed based on forced-air convection for the cylindrical battery pack in the field of electrochemical energy storage

Installing solar collectors to preheat boiler feedwater is one of the most economical methods of repowering steam power plants. The production of freshwater in repowered plants can increase their productivity. The present study aimed at integrating the Bandar Abbas steam power plant's repowered cycles with desalination units and subsequently analyzing the cycles using the R-Curve tool. Three scenarios

Overheating usually occurs in industrial workshops in the summer. The indoor wet bulb globe temperature (WBGT) is a comprehensive evaluation heat stress index for humans exposed to hot environments. Therefore, this study proposed a dynamic method of predicting the indoor WBGT considering the radiation effects. For a sewing workshop in Zhuhai, Guangdong Province, China, the indoor environmental parameters

The temperature of liquid helium (LHe) is 4.2 K, high-performance thermal insulation schemes such as the variable density (VD) and self-evaporation vapor-cooled shield (VCS) are required for LHe tank. However, the working parameters of the VD and VCS in LHe tank have not been investigated. However, the related researches on liquid hydrogen tank neglected the heat transfer of the tank wall and the gap;

The rocket-based combined-cycle engine is considered as a promising scheme to achieve affordable and reusable space transportation. Under the ejector mode, the air mass flow rate is limited by aerodynamic chocking in the mixer of the engine. In other words, the air mass flow rate is determined by the downstream mixing. However for the requirement of critical air mass flow rate, the air stream supplying

Lithium-ion batteries (LIBs) are among the most promising technologies for electric vehicles and electric energy storage systems, while the safety accidents associated with thermal runaway happen frequently. Thermal characteristics and the jet behavior of prismatic LIBs under overheating conditions are still unclear. In this study, the thermal runaway characteristics of LIBs under lengthwise and transversal

The condensation heat transfer and pressure drop characteristics of R600a in a multi-louvered fins compact heat exchanger were studied in detail. Experiments were carried out at saturation pressures from 530 to 620 kPa, mass fluxes from 25 to 41.25 kg∙(m2∙s)−1, air temperature from 25 to 35 oC and inclined angles from 0° to 180° in horizontal and vertical directions, respectively. The effects of mass

A one dimensional analytical model is proposed to analyze the solidification/melting of phase change materials (PCMs) incorporating the shrinkage/expansion void in an annulus. An air-PCM system is considered in this study. Paraffin wax is considered as PCM and filled inside the annulus, while air is considered inside the void. Separation of Variable method involving Bessel’s function is employed to

The constant pressure combustion of the Joule cycle is a dominant source of losses in gas turbines. One possible improvement is pressure gain combustion through pulse detonation combustion. However, the total pressure increase is the result of a transient periodic process that can adversely affect the performance of adjoining turbo components. The thermodynamic benefits of pressure gain combustion

Facing the challenge of high heat flux in electronic devices, effective heat dissipation with low consumption has drawn great attention. Based on the constructal theory, the optimal structures of fractal heat sinks are obtained by genetic algorithm (GA) optimization. The optimal branching level is 4. Furthermore, the Taguchi experimental design is employed to conduct the CFD simulation, and the grey

This paper presents a three-dimensional heat transfer analysis of a flat-plate oscillating heat pipe (OHP). To enhance implementation of OHPs in various applications, it is important to understand the comprehensive phenomena that include thermal diffusion in the whole structure and thermal hydraulics in the channel. We developed an OHP model that includes the effect of thermal diffusion and thermo-fluid

Pulsating heat pipes having non-planar layouts (i.e. three-dimensional layouts) are preferable to the planar geometries when both gravity-independency and compactness are needed. A multi-turn three-dimensional closed loop pulsating heat pipe is tested on ground with the aim of investigating the effects of gravity by means of a quantitative description of the working modes occurring during its operation

The present study describes the development of a preliminary design of a rotor for a radial turbine operating in an organic Rankine cycle. An optimization algorithm is applied to the preliminary design in order to obtain a better configuration of the geometric parameters that provides good quantification of the efficiency in the turbine, a priori, since the application of optimization processes applied

Glass furnaces represent a continuous challenge for CFD simulations, which is attributed to the complex description of multiple phases: the turbulent gas phase, raw materials from a solid glass batch and the laminar liquid phase of the glass melt. Prevalence of unsuitable oxy-fuel combustion models, like the eddy-dissipation model, and the lack of advanced coupling methods for the coupling of combustion

In the present work, an investigation is carried out for the assessment of the energy efficiency improvement, which can be achieved with the employment of a supercritical CO2 power cycle operating in conjunction with a marine Diesel engine. The focus is directed towards the appropriate design of the CO2 cycle, which recovers heat from three distinct waste heat sources exhibiting different temperature

To make a good compromise between the flux uniformity and the high peak flux of the light spot, a new high-flux solar simulator (HFSS) with the continuously adjustable input power of 6–30 kWe was designed and studied in this paper. In the design, three 10 kWe xenon arc lamps, which can provide good solar-like irradiation, were selected as the light sources, and the lamps were reasonably arranged in

In this paper, the present study focuses on innovative design, fabrication, and testing of a solar pure water and hot water hybrid system using a superconducting gas double evacuated tube and heat storage device to achieve a better performance. Exergy analyses of system was made, meanwhile, coefficient of performance and gained output ratio and economic properties has been investigated using data obtained

Cryogenic system is important for the infrared detectors, which can increase the ratio of signal-to-noise at low temperature. Long lifetime, high efficiency mechanical cryocoolers and two-phase heat pipes can reduce the energy consumption of the spacecraft and ensure a low weight. A co-designing cryogenic system consisting of two pulse tube cryocoolers (PTCs) and two neon cryogenic loop heat pipes

In complex outdoor conditions, radical weather changes can sometimes undermine the precision of temperature control systems, mainly because conventional heater controllers lack the ability to adapt to unpredictable parametric variations. In this paper, a heater auto-tuned by a PID neural network was proposed. Without knowing the range of weather variation in advance, the PID neural network self-adapts

Despite their high thermal efficiency (>50%), large two-stroke (2T) diesel engines burning very cheap heavy fuel oil (HFO) produce a high level of carbon dioxide (CO2). To achieve the low emission levels of greenhouse gases (GHG) that will be imposed by future legislation, the use of hydrogen (H2) as fuel in 2T diesel engines is a viable option for reducing or almost eliminate CO2 emissions. In this

Pulsating heat pipe (PHP) has drawn much attention due to its simple structure and high thermal performance. In this study, we proposed a novel PHP with separating walls within the flow channel. This could change the flow pattern of the liquid and vapor plugs, resulting the enhancement of the heat pipe thermal performance. To uncover the effect of the separating wall, we built a 2D numerical model

Room air conditioners are widely used to improve indoor thermal environments. However, the key factors that affect the performance have not been investigated systematically, which greatly influence the application of room air conditioners. Therefore, a subjective questionnaire and objective field test were conducted in this research. In the subjective questionnaire, the main problems, including the

The utilization of biogas as a renewable energy source in power generation systems has been receiving much attention. While gas turbine cycle (GT) systems are commonly used in modern power plants, the reduction of system efficiency owing to the parasite composite in biogas has restricted its sustainable development. Alternatively, the Maisotsenko combustion turbine cycle (MCTC) technology, that recovers

Adsorption heat pumps offer the possibility to provide cold from waste heat, and can therefore be an important component for an environmentally friendly and sustainable cooling supply. A new accurate measurement method is developed to evaluate the progress of performance improvement in this area through new material and heat transfer concepts. The new method covers the entire sample range from very

Among the available mitigation options for CO2 emissions, oxy-fuel combustion technology has been gaining significant attention as a promising technology for curtailing the CO2 emission. Currently the technology is at the demonstration phase on existing coal and gas power plants and some new pilot plants are being tested. In spite of the prospect, to integrate oxy-combustion to fire-tube boilers, heat

The appropriate design of the flow path and operating parameters is needed to improve the efficiency of liquid desiccant systems. This study compared the operation of 30 liquid desiccant systems with different flow paths, which include 6 cooling/heating modes and 5 solution circulation types. The models of the packing tower were established to simulate the heat and mass transfer processes between the

The waste-heat of vapor-absorption refrigeration (VAR) cycles could efficiently power humidification-dehumidification (HDH) desalination systems for freshwater production. The integrated systems reported in the literature relied on water-heated HDH cycles, in which the waste-heat of VAR systems heats the HDH saline water before entering the humidifier. This paper assesses the coupling of an air-heated

In order to establish instructions for high-performance molten salt preparation, this paper focuses on accurate prediction method on the effective heat capacity of nanomaterial-enhanced molten salt (NMS). With carbon nanotube (CNT) enhanced carbonate eutectic (Li2CO3-K2CO3) taken as the study subject, the microscopic mechanism of nanomaterial on the effective specific heat capacity enhancement of molten

Low-speed, high-load is often a short-lasting state for a spark-ignition engine; therefore, the knocking combustion, which is induced by this operating condition, deserves to be analyzed as a dynamic phenomenon in addition to the traditional steady-state approach. That cooling, and, hence engine components temperatures, affects knock tendency is well known. However, a novel interesting point of view

This paper reports a phase change material (PCM) based passively cooled container for integrated rail-road cold chain. It was equipped with cold energy storage plates containing the PCM. A separate charging facility was built to charge the plates. Four kinds of fresh vegetables and fruits were used for integrated rail-road transportation. The charging time and efficiency, the internal temperature and

Solar steam generation has become one of the most promising techniques to realize water purification and desalination owing to the abundance and cleanness of solar energy. Here, we proposed a preheating chamber structure for high-efficiency solar steam generation with carbonized sawdust beds as the solar absorber. Effects of bed porosity on the water transportation, heat transfer and evaporation performance

A novel solution of three-stage waste heat recovery from a gas turbine (11.35 MW) is proposed and its dynamic response characteristics with a series of load and environment change in the process of gas turbine operation is studied according to actual process requirements on an offshore platform. Integrating three processes under different temperature ranges is performed by using the flue gas to heat