R.Z. Wang's research while affiliated with Shanghai Jiao Tong University and other places

Publications (714)

Article
Adsorption refrigeration is one of green cooling technologies while it uses natural refrigerant and can be driven by renewable energy or waste heat. However, its wide application is restricted by the disadvantages of low efficiency and large size. To improve the performance, this paper proposes a new operation strategy based on unequal ad-/desorpti...
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A reduction of CO2 emission from heating industry is urgently required due to the transition of industry towards carbon neutrality. The High-temperature Heat Pump (HTHP) is a valid alternative technology for heating while enhancing energy utilization efficiency to potentially contribute to carbon neutral electrification. Therefore, this study propo...
Article
Humidity always accompanies human beings’ life and industry production. A high humidity environment not only induces health hazards easily but also aggravates energy consumption. Desiccant-based internally-cooled dehumidification using porous sorbents represented by desiccant coated heat exchanger (DCHE) is regarded as the high efficient humidity r...
Article
The continuous improving performance of mobile electronic devices urges a larger heat dissipation capacity, while its improvement is encountering a bottleneck due to the limited cooling area and inherent property of natural convection and radiation. Fortunately, a novel passive cooling technique realized by the moisture sorption-desorption process...
Article
Thermal energy storage based on the sorption process is promising for long-term solar energy and waste heat storage. Aiming at higher ESD (energy storage density), the three-phase absorption process combining vapor absorption and solution crystallization is gaining increasing attention. However, the crystals blocking and long-term vacuum maintenanc...
Article
Heating electrification is a trend for the current carbon neutrality setting. The air-source heat pump (ASHP) has been widely used in residential or commercial buildings to replace household coal-burning stoves due to its higher operating efficiency. Previous studies mainly focused on the heat pump equipment, ignoring the whole system performance i...
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The heat pump heating system has been widely accepted to provide space and water heating in commercial and residential buildings. However, the operating energy performance in practice conditions is limited due to the traditional control strategy. An efficient-cost advanced control strategy is desired to improve the overall operating performance. Th...
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Thermal management of electronic devices is encountering a bottleneck due to the continuously increased heat flux generated from equipment. Fortunately, the development of thermoelectric self-cooling (TESC) technology provides new opportunities for cooling electronic devices passively. In this paper, a practical application of the TESC technology o...
Article
In the process of “Carbon peaking” and “Carbon neutrality”, compression heat pump is an effective technology to supply heat while improving energy utilization efficiency and shifting CO2 emission. In order to promote the application of compression heat pump and provide the most suitable heat pump system, the favorable design logic and selection str...
Article
To extract as much energy as possible from a low-grade heat source in the range of 50–95 °C, a hybrid adsorption refrigeration system using desiccant coated heat exchangers is proposed and investigated in this study. This hybrid system can be operated in three working modes to satisfy various demands for cooling capacity output forms and system per...
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Fresh water scarcity is a globally significant challenge threatening the development of human society. Sorption-based atmospheric water harvesting offers an appealing way to solve this challenge by extracting clean water...
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For countries to realize their carbon neutral targets, space heating is a tough nut to crack. Passive solar heating (represented by Trombe wall) integrating thermal storage is a promising solution. However, current integrated thermal storage technologies fail to meet the demand of continuous heat supply throughout the night. Adsorption thermal batt...
Article
A mathematical model of falling film condenser is developed to predict the dynamic response of shell-and-tube condenser having R1233zd(E) as refrigerant for high temperature heat pump systems. The model incorporates a vapor-mass-flux ratio, which includes the relative velocity slip between vapor and liquid to examine the performance of tube bundles...
Article
Membrane distillation (MD) process is capable of utilizing ultra-low temperature heat (<50 oC), and its compact configuration permits a small module size. Thus a distributed MD device driven by low-grade solar energy for household desalination becomes viable. In this paper, direct solar-heating schemes for vacuum MD (VMD) by photothermal membrane (...
Article
A traditional adsorption refrigeration system cannot run under ultra-low grade heat source temperatures. In order for ultra-low grade heat utilization, a multi-mode integrated system of adsorption refrigeration using desiccant coated heat exchangers (DCHEs) is proposed. The key point of this integrated system is the rise in evaporation temperature...
Article
In order to limit global warming of 1.5°C before 2050, the heat pump with waste heat recovery has been acknowledged as an effective technical solution. In this paper, a new kind of centrifugal heat pump system is applied to recover the waste heat from a steel plant for district heating. Two centrifugal compressors with vapor injection and two-cycle...
Article
Heat pump is effective to recover ultra-low grade waste heat, and includes compression and absorption heat pumps. However, the driving source of these heat pumps are different. This makes the efficiency comparison unfair, and multi-criterion comparison is necessary. In this paper, the compression and absorption heat pumps are compared under the sam...
Article
The shortcomings of conventional working pairs in thermal energy storage and transmission based on absorption cycle have become major obstacles for practical application. Ionic liquids (ILs) are promising alternatives, while only few ILs have been evaluated with enumeration method, by which it is difficult to create a short-term breakthrough. In th...
Article
Numerous novel devices have already utilized desiccant coating to implement various functions, such as atmospheric water harvesting, energy storage, and thermal/humidity management. The mathematical models employed in former literature, for instance the finite-element or finite-volume models usually suffer significant drawbacks such as extreme comp...
Article
Phase change materials (PCMs) have been extensively characterized as promising energy materials for thermal energy storage and thermal management to address the mismatch between energy supply and demand in various energy systems. To overcome the long-standing drawbacks of PCMs, such as low thermal conductivity, liquid leakage, phase separation, and...
Article
The theoretical analysis of the field synergy is tried to apply to desiccant coated heat exchangers (DCHEs) to clarify its coupled heat and moisture transfer characteristics and the way to enhance the characteristics. In this paper, the heat and moisture transfer model of DFHE is established and verified by comparison with experimental data. Three...
Article
High-temperature heat pump is gaining more and more research attention due to the efficient heat supply for industrial uses, which includes waste heat-source, water-source, and air-source types. Although air heat source has lower energy grade, its superior availability is attractive. However, large temperature lift is necessary to fill in the gap b...
Article
Thermal management system that usually based on vapor compression refrigeration system plays a significance role in electric vehicles. The system can be also based on the adsorption refrigeration, which can work for battery waste heat recovery. However, the adsorption refrigeration can hardly operate continuously. To combine the advantage of vapor...
Article
Renewable energy has become very prominent these days because of its sustainable and environment-friendly nature. The soil heat storage system plays an important role in the long-term storage of solar energy to ensure a consistent power supply. The experimental analysis and practical implementation of soil heat storage system are very difficult due...
Article
Desiccant coated heat exchanger (DCHE) has shown great potential for dehumidification in vapor compression cooling systems and has been widely concerned in the research field of air conditioning, as well as heat and mass transfer in recent years. This paper is aimed at providing fundamental knowledge and research progresses on DCHE for dehumidifica...
Article
Atmospheric water harvesting (AWH) is a promising solution to the world’s water shortage. Meanwhile, adsorption-based atmospheric water harvesting (ABAWH) has shown a higher ability to supply water in arid areas using clean and cheap energy. Numerous modern adsorbents for this application have been introduced so far, and many prototypes have been p...
Article
The energy level mismatch between heat sources and industry users has posed a huge barrier for the wide application of local waste heat recovery, which cannot be efficiently addressed by traditional options due to the limited temperature lift. To fill this gap, a hybrid heat transformer is proposed to achieve large temperature lift via deep thermal...
Article
Heat pumps are generally recognized as an efficient energy-saving method, and are widely used in industrial and residential applications. Due to the ratification of the Kyoto Protocol, the use of high-GWP refrigerants is gradually being restricted and they will be phased out for heat pump systems. Currently, low-GWP refrigerants, such as R718, R123...
Article
With the enactment of the Kigali amendment regarding the phase-down of substances with Global Warming Potential (GWP), refrigerants based on HFCs are falling into disuse and low-GWP refrigerants are proposed as replacements. R1233zd(E) is a promising new working fluid for High-temperature Heat Pumps (HTHPs) with low GWP which has yet to be further...
Article
Heating and cooling systems based on hydrogen sorption in metallic alloys have attracted researchers due to their advantages such as environmental friendliness, ability to utilize low-grade waste or renewable energy, wide operating temperature ranges, and availability of a plethora of alloys to choose from. These heat-operated systems offer a viabl...
Article
With strongly decreasing prices of photovoltaics (PV) and battery storage in the past decade, together with incentives for modular construction in China, shipping containers have been suggested as suitable building modules. Transportable modules will ease the process of returning the modules to the factory for reuse and recycling of structural stee...
Article
Gas-solid chemisorption pairs of ammonia and halide salts have edge over other pairs for advanced thermal energy storage batteries due to their abundance, easy availability, cost effectiveness, high sorption capacity, and wide operating temperature range. In the present work, thermodynamic analyses of thermal battery systems are performed for vario...
Chapter
In this chapter, we give a summary for the solid composite sorbents, including the fundamental principle, theory and working pairs of solid sorption, properties of composite sorbents with expanded natural graphite (ENG) matrix, as well as the energy conversion cycles of solid composite sorbents. Basically, the features and the development of solid...
Article
This paper proposes a dynamic programming (DP)-based stochastic model predictive control (SMPC) method for the economic operation of solar PV-powered ice-storage air-conditioning (PIAC) systems. The forecast data of PV generation and building cooling load are considered as stochastic variables in this paper. To deal with the uncertainties of the da...
Article
Thermal energy storage based on sorption method is attractive in view of energy storage density, storage period, and flexibility. Three-phase sorption thermal energy storage is advantageous from high energy storage density, but its temperature lift is low. Besides, further energy storage density enhancement is needed to make the storage system more...
Article
Energy level mismatch between waste heat and energy users poses huge barrier for local waste heat recovery. To tackle this challenge, an energy grade splitting strategy of hot water via absorption heat transformer is proposed. In this strategy, the hot water is separated into two branches. An absorption heat transformer extracts waste heat from the...
Article
China ranks first in the world both for the operating mileage of high-speed railways and the quantity of high-speed trains. The energy consumption of air conditioning ranks second for the sub-systems of high-speed trains. In this paper, a simulation model is created to calculate annual thermal load and electricity consumption hour by hour for Fuxin...
Article
Compact absorber is beneficial for bulk reduction and cost-saving of absorption systems. This paper presents an experimental study on the heat and mass transfer performance of a novel absorber which consists of an S-shaped capillary coils bundle. Experiments were carried out for a practical ammonia-water absorption system under practical working co...
Article
Solid desiccant heat pump system (SDHP) can handle sensible and latent heat load simultaneously with high coefficient of performance (COP). However, in such system, supply air temperature is relatively high and unstable due to the frequent switch between desiccant coated heat exchanger as evaporator and condenser. In order to overcome these drawbac...
Article
In order to achieve a COP of compression heat pumps greater than 6 with the temperature lift of at least 30 °C, a two-cycle parallel connected heat pump system is proposed in this paper. The theoretical simulation of the two-cycle parallel heat pump system is performed and the system performances under different condenser outlet water temperature a...
Article
Latent heat storage using salt hydrates based on tube-fin heat exchanger is a promising heat storage approach for distributed building heating. In spite of abundant experimental investigations, there is quite a lack of numerical works focusing on the industrial-oriented design and optimization on this technology. The present work develops a reasona...
Article
Providing sustainable and affordable housing in rapidly developing regions in East Asia is an essential need, which can be satisfied by the market implementation of prefabricated, modular units, with a high energy-efficient performance. This study presents a comparative analysis of a factory-made residential unit, produced and located in Shanghai,...
Article
Desiccant coated heat exchanger (DCHE), which can be adopted to construct a solar cooling system or desiccant heat pump system, can realize both sensible and latent load removal to provide comfortable supply air. Although it is difficult to avoid condensation in a practical application, the condensation condition of DCHEs is rarely studied. In this...
Article
Global warming is a major environmental concern, which significantly impacts ecological systems and the safety of coastal cities. To address global warming, effective methods must be adopted to reduce greenhouse gas emissions and the consumption of fossil fuels. Vapor compression heat pumps offer an effective way to recover energy from waste heat s...
Article
A novel semi-coupled solid desiccant heat pump (SCSDHP) system, in which a desiccant coated evaporator (DCE) and a conventional evaporator (CE) operate in series, is proposed to realize high COP and improve thermal comfort. In order to determine the parameters of the heat exchanger and verify the superiority of this system, the simulation model of...
Article
In order to overcome the intermittent nature of renewable energy resources, borehole thermal energy storage (BTES) systems are found to be a feasible option these days. Previous research data shows that most of the BTES projects are related to heat storage and there are very few underground cold storage applications. The proposed research work is b...
Article
Absorption heat pump is an effective option for industrial waste heat recovery. However, significant conflict between low evaporation temperature and high efficiency exists in conventional absorption heat pump, which limits its application in deep recovery of low-grade waste heat recovery. To address this issue, this paper presents the use of doubl...
Article
In this study, performance of silica gel rotary wheel system (SRWS) to increase humidity of indoor air in winter is investigated in China. First, an experimental setup is built up to obtain humidification performance of the system under Shanghai winter conditions, and effects of main operation parameters are analyzed. Results show that SRWS can pro...
Article
The search of efficient amine-functionalized materials for direct air capture (DAC) of CO2 is highly attractive to achieve negative emissions. Here we report a new family of class 1 adsorbents for DAC by loading 67 wt.% branched poly(ethylenimine) (PEI) into Mg-Al-CO3 layered double hydroxide-derived mixed metal oxides (MMOs), which exhibit unexpec...
Article
Solar irradiance forecasting is one of the most efficient methods to handle the potential problems caused by the large and frequent photovoltaic fluctuations. For the satellite-based forecasting method, the atmospheric attenuation is paid lesser attention than other parts (notably the cloud effects). This study aims to explore the possibility of im...
Article
Solid desiccant, featuring thermally-driven mass transfer, is nowadays a hotspot in the field of mass adsorption/separation, energy allocation and water harvesting. Former studies indicate that the efficiency in such systems is dominated by the adsorption dynamics of the desiccant-based components. Accordingly, enormous efforts have been attempted...
Article
This article presents solutions for improved energy efficiency by adapting a shipping container building in Shanghai for off-grid operation. While this prototype is based on a single unit, larger buildings made from multiple units constructed at factories is the ultimate goal. Previous studies of container buildings have revealed gaps concerning th...
Article
The traditional point of view suggests photovoltaic systems to be installed at the optimum angles. However, various reasons require more flexible photovoltaic installations, especially for building-integrated photovoltaics. Some site-specific cases based on local irradiance data show that small deviations from the optimum will not cause big energy...
Article
Air humidity, as a source of water, is more or less available everywhere. The sorption capacity of water is a significant factor for the efficiency of atmospheric water harvesting (AWH) systems, which are based on the adsorption phenomenon. Lithium chloride has a high water-uptake rate, but has a very low delinquency relative humidity (DRH). Theref...
Article
This work focuses on the industrialization-oriented investigation of a latent heat storage using a magnesium nitrate hydrate-based composite phase change material. Three aspects of studies are included: (i) characterizations on the thermal-physical properties of the composite, (ii) explorations on the supercooling stability of the composite within...
Article
Latent heat storage using sodium acetate trihydrate is a promising heat storage technology for distributed building heating. However, the industrial and economic feasibility of this heat storage technology has not been proven yet. This work comprehensively carried out industrialization-oriented investigations on this technology from multi-level asp...
Article
Permanent-magnetic Synchronous Frequency-convertible (PSF) compressor as a new technology has been widely used in heating, ventilation and air conditioning. In this paper, a PSF centrifugal compressor was designed and developed. Some key technologies such as large working range 3-Dimensional impeller, 360° circular refrigerant injection port, two-s...
Article
Adsorption thermal storage and transformation (ATST) of low-temperature heat is an energy saving technology towards the efficient use of renewable and waste heat. A solid sorption thermal battery (SSTB) is a promising concept for low-grade heat storage, combined cooling and heating, integrated energy storage and energy upgrade. Current progress in...
Article
High temperature heat pumps (HTHP) with the output temperature above 100 C attract more and more attention in industrial heat recovery. It can effectively elevate the grade of thermal energy and recover waste heat to reduce the consumption of primary energy. In order to compare the performance of different HTHPs, six refrigerants were selected and...
Article
The solar energy utilization has great significance regarding the ever-increasing environment pollution and energy shortage issues. To overcome the instability and intermittency of solar energy, various solar thermal storage technologies have been proposed, and absorption thermal storage is promising for its high energy storage density and long-ter...
Article
Due to the high energy storage density and long-term storage capability, absorption thermal energy storage is attractive for the utilization of solar energy, waste heat, off-peak electricity, and etc. In recent years, absorption thermal energy storage has been intensively studied from thermodynamic cycles, working pairs, and system configurations f...
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Full-text available
Passive vapor generation systems with interfacial solar heat localization enable high-efficiency low-cost desalination. In particular, recent progress combining interfacial solar heating and vaporization enthalpy recycling through a capillary-fed multistage architecture, known as the thermally-localized multistage solar still (TMSS), significantly...
Article
With the advantages of excellent heat transfer performance and less refrigerant charge, falling film evaporator has been widely used in seawater desalination and other industries. However, due to the practical problems of liquid level control and dry patches interactions, the structure design of falling film evaporator should be optimized for refri...
Article
The role of energy storage is to resolve the time-scale mismatch between supply and demand, which plays a key role in high-efficiency and low-carbon energy systems. Based on broad thermal demands, thermal energy storage technologies with high energy density and low cost tend to have greater market potential than the electrochemical batteries. Among...
Article
Full-text available
Distributed renewable energy share increase in electricity generation is creating challenges for the whole power system, due to its intermittent and nonprogrammable nature. Energy storage has the potential to solve those issues although its technical, economic, and environmental impact is up for debate. The paper presents a study about a PV-battery...
Article
In order to increase the utilization of solar energy to lower the effect of photovoltaic power output fluctuations on power grids, an adaptive PID control method to improve the power tracking performance of solar photovoltaic air-conditioners is proposed in this paper. In this method, a dynamic temperature set point of the indoor zone is generated...
Article
Vapor compression very high temperature heat pumps (VHTHPs) with low-GWP refrigerants have attracted enormous attention for waste heat recovery. To yield high temperature output, a water vapor twin-screw compressor with water-injection is developed and a VHTHP prototype is established to conduct the experimental investigation. The experimental resu...
Article
Sorption heat storage is attractive to store solar energy for short-term cooling/heating and long-term heating. The three-phase sorption heat storage is advantageous in energy storage density, but the charging temperature to reach the crystallization is high. In order to eliminate the high charging temperature requirement for the three-phase sorpti...
Article
Desiccant coated heat exchangers (DCHEs), utilizing an inner cooling source to remove sorption heat, are promising alternatives for evaporators and condensers (DCEs/DCCs) in vapor compression (VC) heat pumps. A mathematical model is necessary to facilitate the design, analysis and performance prediction of the component and the relevant systems. In...
Article
Sensible heat transportation with water is widely adopted in traditional heating network, which suffers from the low energy transportation density and inevitable heat loss for long-distance heat transportation. To address these two issues, the solution transportation absorption system has been proposed, which transports the thermal energy by stable...
Article
Water scarcity is a current concern and a future problem. Air-water harvesting (AWH) is a novel proposed solution to provide enough water for human-being's needs especially in remote areas. However, the sorbent material is one of the challenging components of these systems. Generally, a proper sorbent must have a high water uptake capacity, a low r...
Article
In this forward-looking perspective, the current research status of latent heat storage using salt hydrates for building heating are firstly analyzed from aspects of material development, performance evaluation, heat transfer enhancement and application feasibility. Based on the analysis, barriers for the further promotion of this technology, inclu...
Article
Removing benzene from indoor space plays an important role in indoor air purification. A novel filter with vegetal fiber paper (VFP) as matrix hosting silica gel is proposed in this paper for benzene removal. In order to investigate the feasibility and performance of this idea, firstly, three pieces of VFP samples impregnated with different amounts...
Article
Zeolite NaX is one of the most popular water sorption materials for dehumidification, thermal energy storage and sorption cooling. In this paper, zeolite NaX is modified by magnesium chloride to achieve ion-exchange (zeolite NaMgX) and salt impregnation (zeolite NaX/MgCl2) with the aim of improving water sorption capacity and thermal performance. T...
Article
Thermal energy storage is a key technology to promote renewable energy application and utilization of off-peak electricity for space heating and hot water. Hydrated salt is one kind of promising phase change materials for thermal energy storage but it usually has the common drawbacks of phase separation, high supercooling degree and poor thermal co...
Article
In order to solve the problems of atmospheric pollution and haze caused by traditional coal-fired heating, the promotion and application of clean energy heating methods is urgently needed. The air-source heat pumps are applied in the residential buildings to replace traditional coal-fired heating in Beijing and Tianjin. Limited to the cost and econ...
Article
For considerate use of limited freshwater resources in arid regions, it is very important to recycle the evapotranspiration water in greenhouse production for sustainable agriculture. In addition, in a typical greenhouse, ideal conditions for plants are set at low temperature, which is provided by evaporative cooling systems and ventilation, and th...
Article
Centrifugal heat pumps with waste heat recovery have a bright application future in industry field due to their large heating capacity and high supply water temperature. Two kinds of advanced heat pump systems are proposed and analyzed to improve the energy efficiency. The system performances are analyzed and compared for three kinds of centrifugal...
Article
The Multi-function thermal system with wide temperature range (−50 °C to 160 °C) is proposed. As the cooling also belongs to a type of thermal energy supply, the proposed system can output several integrated heat source at the same time, named Multi-function thermal system finally. It is composed of refrigeration, heat recovery, vapor generation an...
Article
A novel multi-form thermochemical energy storage method is proposed for high energy-density thermal energy storage based on multi-step sorption processes. The proposed multi-form thermochemical energy storage combines the physisorption energy storage of a porous matrix, the chemisorption energy storage of a salt hydrate, and the absorption energy s...
Article
Decreasing prices of photovoltaics (PV) and Lithium-ion batteries are creating a significant momentum for off-grid Zero Energy Buildings (ZEBs). In literature, most researchers have focused on grid-connected ZEBs built on site. This literature review is written with factory-made off-grid ZEBs in mind. High investment costs, poor construction qualit...
Article
DCHE (Desiccant coated heat exchanger) based heat pump systems can handle sensible and latent loads simultaneously and separately within one single component via flowing refrigerant and coated desiccant. Their characteristics have a crucial impact on the performance of the whole system. To ensure energy efficiency of DCHE based systems, the restric...