Hongxing Yang

• The Hong Kong Polytechnic University

The transition towards third-generation concentrated solar power (CSP) systems necessitates advanced working fluids, with supercritical carbon dioxide (sCO2) emerging as a prime candidate. This study employed a rarely used discretised 1-D mathematical model to thoroughly explore and parametrically analyse the performance of sCO2 in a parabolic trou...

This research addresses advancements towards third-generation concentrated solar power (CSP) systems, highlighting the critical need for improved system efficiency through advanced power cycles and optimized waste heat utilisation. By integrating a direct parabolic trough solar collector (PTSC) with a supercritical CO₂ (sCO₂) Brayton cycle and dire...

This research advances current efforts to develop 3rd gen concentrated solar power (CSP) systems, addressing current research and practical implementation gaps. It focuses on key challenges identified by the academic community: advanced power cycles and utilising waste heat effectively to enhance efficiency. This research introduced a novel system...

The rapid development of data centers (DCs) has led to a marked increase in energy consumption in recent years, which poses a direct challenge to global efforts aimed at reducing carbon emissions. In regions with hot and humid climates, the energy demand is largely driven by air conditioning systems necessarily to maintain appropriate operational t...

Air-conditioning systems in hot and humid regions account for over 50% of total energy usage. Integrating an indirect evaporative cooling (IEC) and a liquid desiccant dehumidifier (LDD) as the liquid desiccant cooling system (LDCS) presents an energy-saving and emission-reducing solution to replace traditional mechanical vapor compression refrigera...

Despite the recognition of its energy-saving potential, the promotion of liquid desiccant air-conditioning system is limited by the drawbacks of existing desiccants in long-term or large-scale use. Deep eutectic solvent with good bio- and eco- friendliness has not yet been tested for systematic study in air-conditioning system. In this paper, a dee...

Reliable and continuous power supply to the data monitoring and transmitting devices of the water intelligent network (WIN) system of urban water supply pipelines is still a challenge due to the restricted underground space and complex water environment. In this study, a novel inline bidirectional vertical crossflow turbine (IBVCT) integrated with...

It is challenging to reduce the massive radiation heat loss from the parabolic trough solar receiver and enhance the solar utilization efficiency of the parabolic trough collector (PTC) system. On the basis of the negative thermal-flux phenomenon discovered in the PTC system, a novel PTC system integrated with photovoltaic (PTC-PV) panels is propos...

Industrial CO2 emission, accounting for nearly a quarter of the total CO2 emission, is a “hard-to-abate” emission sector, owing to the longstanding challenge in reducing CO2 emission while not sacrificing industry economics. Herein, this research proposes an integrated solar-driven CO2 capture system for application in industrial buildings to decar...

Tower receivers in next-generation concentrated solar power towers (SPTs) face an increasing challenge to suppress the massive radiation heat loss associated with an elevated operating temperature. Negative thermal-flux regions (NTRs) exist in tower receivers owing to the high but uneven temperature and solar concentration ratio on their surfaces....

Supercritical carbon dioxide (s-CO_2) has been gaining prominence among researchers due to its ability to operate at high temperatures and overcome the current state-of-the-art parabolic trough solar collector system’s limitation. This research aims to investigate the energetic, exergetic and entropy performance of the PTSC under a wide range of op...

Liquid desiccant air-conditioning system (LDAS) becomes an attractive option for reducing the energy consumption of conventional air-conditioning systems. Despite lots of published papers on LDAS in various aspects, there is not yet a comprehensive and up-to-date review on the properties of liquid desiccants, while the selection of liquid desiccant...

Yaw control is one of the most promising active wake control strategies to maximize the total power generation of wind farms. Meanwhile, structural performance needs to be considered in yaw misalignment in case the adverse structural performance offsets the benefit of yaw control in power enhancement. However, an efficient and accurate prediction m...

Green buildings desire low CO2 emission and high indoor air quality (IAQ), which, however, are inherently conflicted on energy consumption and cannot be achieved simultaneously in air conditioning-based ventilation methods. One alternative can be combining building-integrated renewable energy and CO2 capture technology to remove CO2 from stale indo...

Condition monitoring of assets is significant to the efficiency and reliability of industrial automation systems. However, the accuracy of condition monitoring results is easily impaired by variational environments and volatile operations, especially for complex automation systems. In this article, an environmentally adaptive and contrastive repres...

The solar power tower (SPT) is one of the dominant applications of concentrating solar power technology. The tower receiver, as the core component of the SPT system, is responsible for solar absorption and conversion by virtue of the solar absorbing coating (SAC) deposited on the receiver surface. The SAC exerts a crucial role in the activity of th...

This study develops net-zero energy management and optimization approaches for the commercial building sector in cities powered by renewable energy systems integrated with energy storage of pumped hydro and hydrogen taxis, based on the estimated installation potential of solar photovoltaics and offshore wind power. A novel time-of-use energy manage...

This study aims to develop uncertainty energy planning of net-zero energy communities with innovative peer-to-peer energy trading management and advanced green vehicle storage considering climate changes by 2050 with transient system modelling, stochastic uncertainty sampling and data-driven machine learning predictions. The future-oriented peer-to...

The data-driven models of various air conditioning (AC) systems have been developed because of the wider application of machine learning in the engineering field. Indirect evaporative cooler (IEC), known as one of the effective and environment-friendly AC devices, achieves the cooling purpose without using any types of mechanical compressors or che...

Wind turbine (WT) experiments in wind tunnels can benefit the efficient utilization of wind energy in many aspects, such as the testing of new products, the validation of numerical models, and the exploration of underlying mechanisms of WT-induced flow field. However, there is a lack of comprehensive and critical review on this topic. In this paper...

In practice, the actual operation conditions are generally different from those assumed in the design stage, which causes uncertainties of actual building load and photovoltaic (PV) power generation. This study conducted an optimization design for PV-battery (PVB) system with consideration of these uncertainties. Three groups of factors with uncert...

Using auxiliary internal cooling is an effective way to improve the dehumidification effectiveness of the liquid desiccant dehumidifier (LDD) compared with the adiabatic dehumidifier. Indirect evaporative cooling (IEC) is a promising solution for internal cooling owing to its high efficiency and environmentally friendly features. A hexagonal plate...

In response to the worldwide call for energy conservation and carbon emission reduction, indirect evaporative cooling as a green and environmentally friendly technology has been extensively researched and developed. In the practical application of this technology, the spray nozzle arrangement results in different wettability factors of the wet chan...

Indirect evaporative cooler (IEC) is treated as an energy-efficient and low carbon-emission air conditioning solution without utilizing the mechanical compressor and chemical refrigerants for cooling production. Currently, the widely-used one-dimensional (1-D) and two-dimensional (2-D) numerical models of IEC can expose the temperature and humidity...

Air-conditioning systems consume a large amount of energy with the rising thermal requirement of indoor environments. Indirect evaporative cooler (IEC), which is recognized to partially substitute conventional air-conditioning devices, has been studied extensively to supply the cool air at the cost of less energy in buildings. Existing literature r...

Current solar-driven carbon capture by adsorption (CCA) technologies are mostly based on applying solar-thermal devices to power the regeneration process, which results in a very low solar exergy efficiency and requires external power input. This paper integrates solar photovoltaic/thermal (PV/T) and CCA technologies to form a new solar cascade uti...

In recent years, building-integrated photovoltaic (BIPV) windows have drawn attention from both the building industry and academic society. As a multifunctional application of photovoltaic technologies, semi-transparent BIPV panels can generate renewable energy in situ and play the role of typical windows. Unlike those PV windows made by crystallin...

Ambient fine particulate matter (PM2.5) could be a potential environmental risk for decreasing the available solar energy resources and solar photovoltaic (PV) power generation. This study quantifies the attenuation effects of PM2.5 on surface solar irradiance and system performance of different solar PV technologies in Hong Kong. The analysis base...

The low carbon building design has become critical given the urgent need to reduce global carbon emissions. Reducing operational energy use through multi-objective optimizations used to be a common approach, but its validity is impaired by surging embodied impacts. Therefore, a life cycle optimization becomes necessary to improve the overall carbon...

The proper operation strategy is of great importance for photovoltaic-battery (PVB) systems to achieve desirable performance. Therefore, it’s necessary to identify and evaluate the characteristics of different operation strategies for engineering application. In this study, three operation strategies including the dynamic programming (DP)-based str...

CsxWO3 nanocrystals which exhibit localized surface plasmon resonance (LSPR) and small polaron transfer in wavelength of the near-infrared radiation have attracted great attention to fabricate the spectrally selective coating. Enhancing the LSPR and small polaron transfer of CsxWO3 nanocrystals is effectively achieved by introducing aliovalent dopa...

Reducing the lifecycle energy use of buildings with renewable energy applications has become critical given the urgent need to decarbonize the building sector. Multi-objective optimizations have been widely applied to reduce the operational energy use of buildings, but limited studies concern the embodied or whole lifecycle energy use. Consequently...

The controllable one-pot synthesis of hexagonal CsxWO3 nanocrystals without post heat-treatment remains a great challenge in the field of nanocrystal materials. In this study, a facile one-pot method for controllable synthesis of CsxWO3 nanocrystals was proposed using stable and relatively cheap ammonium metatungstate and cesium carbonate as starti...

Spectrally selective materials have been widely used to shield near-infrared radiation for windows in the region with a cooling-demand climate. CsxWO3 nanocrystals which exhibit strong localized surface plasmon resonance (LSPR) effect and small polaron transfer in near-infrared radiation have attracted great attention for fabricating the spectrally...

Large-scale turbines’ wake expansion is influenced both by atmospheric conditions and terrain effects. This paper conducted comparative experimental measurements on the wind turbines’ wake in three wind farms areas of different terrain complexities using Doppler Light Detection and Ranging (LiDARs). Three wind farm areas of different terrain comple...

The traditional indirect evaporative cooler (IEC) needs the consistent working of the pump for water spraying to the secondary air channel wall, which consumes an amount of energy and causes the extra pressure drop. Improving the channel surface water retention capacity has drawn research attentions over the years, and using porous materials is exp...

An indirect Evaporative Cooler (IEC) for air-conditioning (AC) energy recovery is a rapidly developing technology and has great potential applications in hot and humid regions. As the cooling potential of exhaust air is captured to evaporate the spraying water, the humid fresh air in adjacent channels can be cooled with moisture extracted. The cond...

Ground source heat pump (GSHP) is widely studied for building energy efficiency but suffers from soil thermal imbalance and performance deterioration in heating-dominant regions. Photovoltaic (PV) collector is commonly used for renewable energy, but the efficiency is constrained by the PV module temperature. The combination of GSHP and photovoltaic...

This study develops peer-to-peer energy trading management and optimization approaches of renewable energy systems integrated with energy storage of hydrogen and battery vehicles for power supply to a diversified net-zero energy community. Typical net-zero energy community models are developed and compared with different storage vehicle types (hydr...

Solar power tower (SPT) is regarded as the most promising technology for applications in concentrating solar power. However, a significant decrease in the solar-thermal conversion efficiency of the tower receiver in the SPT system occurs at high operating temperatures due to the massive radiation heat loss caused. In this work, a detailed heat tran...

Hexagonal cesium tungsten bronze (CsxWO3) nanocrystals have attracted great attention in the field of energy-efficient windows, which exhibit the localized surface plasmon resonance (LSPR) effect and small polaron transfer in near-infrared radiation (NIR). The enhancement of the LSPR effect can be achieved by introducing aliovalent dopant into the...

A photovoltaic/thermal (PV/T) technology, producing electricity and heat simultaneously, has attracted extensive attention. Integration of phase change materials (PCMs) into PV/T systems as auxiliary cooling media or/and heat storage media to improve the system performances has been prevalent in recent years. This paper aims to critically and compr...

BIPV windows integrate solar cells within window glazing and do not only retain the functionality of conventional windows but also provide other benefits such as electricity generation and thermal insulation. BIPV windows are categorized into single glazed BIPV windows, double glazed BIPV windows with/without ventilation and vacuum BIPV windows dep...

This study presents peer energy trading management approaches in a net-zero energy community with fundamental units of university campus, commercial office and high-rise residential building groups as per actual energy consumption and simulation data. Hybrid solar photovoltaic and wind turbine systems are developed for power supply to the diversifi...

Modular construction has attracted increasing attention due to its energy and environmental benefits. Digital technologies such as building information modelling (BIM) have also been explored to generate and manage data through the lifecycle of buildings. Although research has been performed in the area of integrating BIM and modular construction,...

Solar photovoltaic (PV) is a promising and highly cost-competitive technology for sustainable power supply, enjoying a continuous global installation growth supported by the encouraging policies and commercial markets. However, air pollution and soiling of PV modules prevail worldwide, potentially casting a shadow on solar PV power generation. This...