Imperial College London

DrGanHuang

Faculty of EngineeringDepartment of Chemical Engineering

Honorary Research Fellow
 
 
 
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g.huang

 
 
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ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

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23 results found

Madurai Elavarasan R, Mudgal V, Selvamanohar L, Wang K, Huang G, Shafiullah GM, Markides CN, Reddy KS, Nadarajah Met al., 2022, Pathways toward high-efficiency solar photovoltaic thermal management for electrical, thermal and combined generation applications: A critical review, Energy Conversion and Management, Vol: 255, Pages: 1-31, ISSN: 0196-8904

Photovoltaic (PV) panels convert a portion of the incident solar radiation into electrical energy and the remaining energy (>70 %) is mostly converted into thermal energy. This thermal energy is trapped within the panel which, in turn, increases the panel temperature and deteriorates the power output as well as electrical efficiency. To obtain high-efficiency solar photovoltaics, effective thermal management systems is of utmost. This article presents a comprehensive review that explores recent research related to thermal management solutions as applied to photovoltaic technology. The study aims at presenting a wide range of proposed solutions and alternatives in terms of design approaches and concepts, operational methods and other techniques for performance enhancement, with commentary on their associated challenges and opportunities. Both active and passive thermal management solutions are presented, which are classified and discussed in detail, along with results from a breadth of experimental efforts into photovoltaic panel performance improvements. Approaches relying on radiative, as well as convective heat transfer principles using air, water, heat pipes, phase change materials and/or nanoparticle suspensions (nanofluids) as heat-exchange media, are discussed while including summaries of their unique features, advantages, disadvantages and possible applications. In particular, hybrid photovoltaic-thermal (PV-T) collectors that use a coolant to capture waste heat from the photovoltaic panels in order to deliver an additional useful thermal output are also reviewed, and it is noted that this technology has a promising potential in terms of delivering high-efficiency solar energy conversion. The article can act as a guide to the research community, developers, manufacturers, industrialists and policymakers in the design, manufacture, application and possible promotion of high-performance photovoltaic-based technologies and systems.

Journal article

Huang G, Markides CN, 2021, Spectral-splitting hybrid PV-thermal (PV-T) solar collectors employing semi-transparent solar cells as optical filters, Energy Conversion and Management, Vol: 248, Pages: 1-15, ISSN: 0196-8904

Spectral splitting is a promising design methodology that can significantly improve the performance of hybrid photovoltaic-thermal (PV-T) collectors. However, conventional spectral-splitting PVT (SSPVT) collectors require additional optical components, which significantly increases the complexity and cost of the collector. This study proposes SSPVT collector designs that employ semi-transparent photovoltaic (PV) solar cells, which act as both the electricity generator as well as the spectral-splitting optical filter. In these designs, a part of the solar spectrum is absorbed by the semi-transparent solar cells for electricity generation, while the rest (especially the near-infrared region of the solar spectrum) is transmitted to an absorber where it generates a high-temperature thermal energy output. Three types of emerging semi-transparent solar cells, i.e., cadmium telluride (CdTe), perovskite solar cells (PVSCs) and polymer solar cells (PSCs), are selected for investigation in this context. A comprehensive two-dimensional model of such SSPVT collectors is developed and used to investigate their electrical and thermal performance. The results show that the proposed designs are effective at thermally decoupling the PV cells from the solar thermal absorber, thereby promoting a higher electrical efficiency and enabling the simultaneous generation of low-temperature thermal energy (<60 °C), along with high-temperature thermal energy (100–200 °C) under one sun. For example, a PVSC-based SSPVT collector is shown to be capable of simultaneously generating: electricity with an efficiency of 13.8%, high-temperature heat (150 °C) with a thermal efficiency of 21.1%, and low-temperature heat (50 °C) with a thermal efficiency of 22.5%. The relative performance between the CdTe-, PVSC- and PSC-based collectors depend on the relative value of the high-temperature thermal energy to that of electricity. It is concluded that semi-transparent solar cells are

Journal article

Huang G, Wang K, Riera Curt S, Franchetti B, Pesmazoglou I, Markides Cet al., 2021, On the performance of concentrating fluid-based spectral-splitting hybrid PV-thermal (PV-T) solar collectors, Renewable Energy, Vol: 174, Pages: 590-605, ISSN: 0960-1481

Concentrating fluid-based spectral-splitting hybrid PV-thermal (SSPVT) collectors are capable of high electrical and thermal efficiencies, as well as high-temperature thermal outputs. However, the optimal optical filter and the maximum potential of such collectors remain unclear. In this study, we develop a comprehensive two-dimensional model of a fluid-based SSPVT collector. The temperature distributions reveal that these designs are effective in thermally decoupling the PV module from the high-temperature filter flow-channel, improving the electrical performance of the module. For a Si solar cell-based SSPVT collector with optical filter #Si400-1100, the filter channel is able to produce high-temperature thermal energy (400 °C) with an efficiency of 19.5%, low-temperature thermal energy (70 °C) with an efficiency of 49.5%, and electricity with an efficiency 17.5%. Of note is that the relative fraction of high-temperature thermal energy, low-temperature thermal energy and electricity generated by such a SSPVT collector can be adjusted by shifting the upper- and lower-bound cut-off wavelengths of the optical filter, which are found to strongly affect the spectral and energy distributions through the collector. The optimal upper-bound cut-off always equals the bandgap wavelength of the solar cell material (e.g., 1100 nm for Si, and 850 nm for CdTe), while the optimal lower-bound cut-off follows more complex selection criteria. The SSPVT collector with the optimal filter has a significantly higher total effective efficiency than an equivalent conventional solar-thermal collector when the relative value of the high-temperature heat to that of electricity is lower than 0.5. Detailed guidance for selecting optimal filters and their role in controlling SSPVT collector performance under different conditions is provided.

Journal article

Tripanagnostopoulos Y, Huang G, Wang K, Markides Cet al., 2021, Photovoltaic/Thermal Solar Collectors, Reference Module in Earth Systems and Environmental Sciences

Journal article

Liang Z, Wang K, Huang G, Markides CN, Chen Qet al., 2021, Thermodynamic analyses of a solar-hydrogen energy system based on SBS PV-T and SOEC/SOFC technologies, 5-6th Thermal and Fluids Engineering Conference (TFEC), Publisher: Begellhouse, Pages: 1323-1326

Spectral-beam splitting (SBS) hybrid photovoltaic-thermal (PV-T) collectors are able to generate, from the same aperture area, both electricity and thermal energy, at a temperature high enough to make this useful in a wide range of applications. This is a promising technology, especially in area-constrained environments, as it can achieve very high overall (electrical plus thermal) efficiencies. Combining SBS PV-T collectors with reversible solid oxide electronic cell/solid oxide fuel cell (SOEC/SOFC) systems can help address the intermittent nature of the solar resource, since the collected solar energy by the SBS PV-T collectors can be converted to and stored as hydrogen by the SOEC module. If and when needed, the hydrogen can later be converted back to electricity by the SOFC module. In this paper, we present numerical models that has been developed for the SBS PV-T collector and SOEC/SOFC system. Parametric analyses based on these models have been performed in order to identity operational characteristics and optimal designs, looking to integrated systems that maximize overall energy efficiency. It is found that the water vapor temperature and flow rate through the SOEC/SOFC module are crucial for the performance of this component, but that this leads to a reduced SBS PV-T collector thermal efficiency. Based on the results, we propose a novel hybrid solar-hydrogen system concept that involves combining SBS PV-T collectors, a Rankine cycle engine and a reversible SOEC/SOFC module.

Conference paper

Huang G, Wang K, Markides CN, 2021, Efficiency limits of concentrating spectral-splitting hybrid photovoltaic-thermal (PV-T) solar collectors and systems, Light: Science and Applications, Vol: 10, Pages: 1-1, ISSN: 2047-7538

Spectral splitting is an approach to the design of hybrid photovoltaic-thermal (PVT) collectors that promises significant performance benefits. However, the ultimate efficiency limits, optimal PV cell materials and optical filters of spectral-splitting PVT (SSPVT) collectors remain unclear, with a lack of consensus in the literature. We develop an idealized model of SSPVT collectors and use this to determine their electrical and thermal efficiency limits, and to uncover how these limits can be approached through the selection of optimal PV cell materials and spectral-splitting filters. Assuming that thermal losses can be minimized, the efficiency limit, optimal PV material and optimal filter all depend strongly on a coefficient w, which quantifies the value of the delivered thermal energy relative to that of the generated electricity. The total (electrical plus thermal) efficiency limit of SSPVT collectors increases at higher w and at higher optical concentrations. The optimal spectral-splitting filter is defined by sharp lower- and upper-bound energies; the former always coincides with the bandgap of the cell, whereas the latter decreases at higher w. The total effective efficiency limit of SSPVT collectors is over 20% higher than those of either standalone PV modules or standalone ST collectors when w is in the range from 0.35 to 0.50 and up to 30% higher at w ≈ 0.4. This study provides a method for identifying the efficiency limits of ideal SSPVT collectors and reports these limits, along with guidance for selecting optimal PV materials and spectral-splitting filters under different conditions and in different applications.

Journal article

Huang G, Markides C, 2020, On the potential of employing semi-transparent solar cells as optical filters for spectral-splitting hybrid PV-thermal (PV-T) solar collectors, International Conference on Applied Energy 2020

Conference paper

Huang G, Curt SR, Wang K, Markides CNet al., 2020, Challenges and opportunities for nanomaterials in spectral splitting for high-performance hybrid solar photovoltaic-thermal applications: A review, Nano Materials Science, Vol: 2, Pages: 183-203, ISSN: 2589-9651

Hybrid photovoltaic-thermal (PV-T) collectors, which are capable of cogenerating useful thermal energy and electricity from the same aperture area, have a significantly higher overall efficiency and ability to displace emissions compared to independent, separate photovoltaic panels, solar thermal collectors or combinations thereof. Spectral splitting has emerged as a promising route towards next-generation high-performance PV-T collectors, and nanotechnology plays an important role in meeting the optical and thermal requirements of advanced spectral splitting PV-T collector designs. This paper presents a comprehensive review of spectral splitting technologies based on nanomaterials for PV-T applications. Emerging nanomaterials (nanofluids, nanofilms and nanowires) suitable for achieving spectral splitting based on reflection, diffraction, refraction and/or absorption approaches in PV-T collectors are presented, along with the associated challenges and opportunities of these design approaches. The requirements from such materials in terms of optical properties, thermal properties, stability and cost are discussed with the aim of guiding future research and innovation, and developing this technology towards practical application. Nanofluids and nanofilms are currently the most common nanomaterials used for spectral splitting, with significant progress made in recent years in the development of these materials. Nevertheless, there still remains a considerable gap between the optical properties of currently-available filters and the desired properties of ideal filters. Aiming to instruct and guide the future development of filter materials, a simple generalized method is further proposed in this paper to identify optimal filters and efficiency limits of spectral splitting PV-T systems for different scenarios. It is found that the optimal filter of a spectral splitting PV-T system is highly sensitive to the value of thermal energy relative to that of electricity, which t

Journal article

Huang G, Zhu Y, Liao Z-Y, Huang Z, Jiang P-Xet al., 2020, Transpiration cooling with bio-inspired structured surfaces, Bioinspiration &amp; Biomimetics, Vol: 15, Pages: 036016-036016

Journal article

Huang G, Wang K, Curt SR, Franchetti B, Pesmazoglou I, Markides CNet al., 2020, Performance analysis of fluid-based spectralsplitting hybrid photovoltaic-thermal solar collectors, Pages: 1248-1259

Fluid-based spectral-splitting technology has appears as a promising approach for enabling high electrical and thermal efficiencies from hybrid PV-thermal (PVT) collectors, as well as a high-temperature thermal energy output. In this study, we develop a model of a fluid-based spectral-splitting PVT system under a solar concentration of 50, and use this to explore the electrical and thermal performance of such a system. In this design, part of the spectrum is absorbed by an ideal fluid-based filter, thereby avoiding unnecessary heating of the PV module. A cooling channel, which is attached to the bottom of the PV module, removes waste heat from the cells and produce a low-temperature (60-80 °C) thermal output, while a second fluid stream through the collector is heated by the filter channel to a higher-temperature level (200-400 °C). The spectral and thermal energy distributions through the collector are simulated and analysed. We also investigate the influence of the solar cell material (Si and CdTe) and mass flux ratio on collector performance. The ideal fluid filters that are applied to the collector are able to absorb 27% of the solar energy that cannot be converted by the Si cells (39% for the CdTe module), significantly reducing the heating of the cells. The Si-based collector is able to generate high-temperature heat (400 °C) with an efficiency of 20% simultaneously with low-temperature heat (75 °C) with an efficiency of 50%, and electricity at an efficiency of 17%. The CdTe-based collector is able to simultaneously generate high-temperature heat (400 °C), low-temperature heat (64 °C) and electricity with efficiencies of 33%, 38% and 18%, respectively. These output temperatures and efficiencies can be adjusted over a wide range by changing the mass flux ratio to meet the demands of different users and applications.

Conference paper

Huang G, Liao Z, Xu R, Zhu Y, Jiang P-Xet al., 2020, Self-pumping transpiration cooling with a protective porous armor, Applied Thermal Engineering, Vol: 164, Pages: 1-10, ISSN: 1359-4311

Self-pumping transpiration cooling is an advanced and effective method for cooling a high heat flux surface without the assistance of pumps and control systems. This study demonstrates a novel structure for self-pumping transpiration cooling with a protective porous armor structure. The results showed that the cooling system successfully drove liquid water without any pumps and effectively cooled the heated surface. The water evaporated at the interface between the porous armor and the sintered porous plate, and then the vapor was exhausted through the porous armor with secondary heat convection cooling. The coolant mass flow rate reduced coolant consumption by approximately 39% with the aid of the porous armor. The self-pumping transpiration cooling system automatically adjusted the coolant mass flow according to different mainstream conditions. The surface temperature of the sintered porous plate maintained a near constant value under different mainstream conditions, while the temperature of the porous armor changed along with the mainstream conditions. The self-pumping transpiration cooling system was effective owing the protection of the porous armor, even when the outside porous surface had an evident blockage. Thus, the reliability of the self-pumping system was improved.

Journal article

Huang G, He L, 2019, Influence of inhomogeneous porosity on effusion cooling, International Journal of Heat and Mass Transfer, Vol: 144, Pages: 118675-118675, ISSN: 0017-9310

Journal article

Huang G, Liao Z, Xu R, Zhu Y, Jiang P-Xet al., 2019, Self-pumping transpiration cooling with phase change for sintered porous plates, Applied Thermal Engineering, Vol: 159, Pages: 113870-113870, ISSN: 1359-4311

Journal article

Min Z, Huang G, Parbat SN, Yang L, Chyu MKet al., 2019, Experimental Investigation on Additively Manufactured Transpiration and Film Cooling Structures, Journal of Turbomachinery, Vol: 141, ISSN: 0889-504X

<jats:p>The last 50 years has witnessed significant improvement in film cooling technologies while transpiration cooling is still not implemented in turbine airfoil cooling. Although transpiration cooling could provide higher cooling efficiency with less coolant consumption compared to film cooling, the fine pore structure and high porosity in transpiration cooling metal media always raised difficulties in conventional manufacturing. Recently, the rapid development of additive manufacturing (AM) has provided a new perspective to address such challenge. With the capability of the innovative powder bed selective laser metal sintering (SLMS) AM technology, the complex geometries of transpiration cooling part could be precisely fabricated and endued with improved mechanical strength. This study utilized the SLMS AM technology to fabricate the transpiration cooling and film cooling structures with Inconel 718 superalloy. Five different types of porous media including two perforated plates with different hole pitches, metal sphere packing, metal wire mesh, and blood vessel shaped passages for transpiration cooling were fabricated by EOS M290 system. One laidback fan-shaped film cooling coupon was also fabricated with the same printing process as the control group. Heat transfer tests under three different coolant mass flow rates and four different mainstream temperatures were conducted to evaluate the cooling performance of the printed coupons. The effects of geometry parameters including porosity, surface outlet area ratio, and internal solid–fluid interface area ratio were investigated as well. The results showed that the transpiration cooling structures generally had higher cooling effectiveness than film cooling structure. The overall average cooling effectiveness of blood vessel-shaped transpiration cooling reached 0.35, 0.5, and 0.57, respectively, with low (1.2%), medium (2.4%), and high (3.6%) coolant injection ratios. The morphological parameters anal

Journal article

Huang G, Zhu Y, Liao Z, Xu R, Jiang P-Xet al., 2019, Biomimetic self-pumping transpiration cooling for additive manufactured porous module with tree-like micro-channel, International Journal of Heat and Mass Transfer, Vol: 131, Pages: 403-410, ISSN: 0017-9310

Journal article

Huang G, Min Z, Yang L, Jiang P-X, Chyu Met al., 2018, Transpiration cooling for additive manufactured porous plates with partition walls, International Journal of Heat and Mass Transfer, Vol: 124, Pages: 1076-1087, ISSN: 0017-9310

Journal article

Huang G, Zhu Y, Liao Z, Jiang P-Xet al., 2018, Experimental investigation of self-pumping internal transpiration cooling, International Journal of Heat and Mass Transfer, Vol: 123, Pages: 514-522, ISSN: 0017-9310

Journal article

Huang G, Zhu Y-H, Huang Z, Jiang P-Xet al., 2018, Investigation of Combined Transpiration and Opposing Jet Cooling of Sintered Metal Porous Struts, Heat Transfer Engineering, Vol: 39, Pages: 711-723, ISSN: 0145-7632

Journal article

Huang G, Zhu YH, Jiang PX, Huang Zet al., 2018, Investigation of Inclined Porous Transpiration-Cooled Struts, Journal of Spacecraft and Rockets, Vol: 55, Pages: 660-668, ISSN: 0022-4650

Journal article

Huang G, Zhu Y, Liao Z, Lu T, Jiang P-X, Huang Zet al., 2018, Experimental Study on Combined Cooling Method for Porous Struts in Supersonic Flow, Journal of Heat Transfer, Vol: 140, ISSN: 0022-1481

<jats:p>A combined transpiration and opposing jet cooling method was experimentally investigated for protecting porous struts with microslits in the leading edge. Schlieren images showed that this cooling method significantly affects the stability of the flow field and the profile of the detached shock wave. Three different states of flow fields were observed when increasing the coolant injection pressure of a strut having a 0.20 mm wide microslit. The detached bow shock was pushed away by the opposing jet; it then became unstable and even disappeared when the coolant injection pressure was increased. Combined transpiration and opposing jet cooling could effectively cool the entire strut, especially the leading edge. The leading edge cooling efficiency increased from 3.5% for the leading edge without a slit to 52.8% for the leading edge with a 0.20 mm wide slit when the coolant injection pressure was 0.55 MPa. Moreover, combined transpiration and opposing jet cooling with nonuniform injection distribution made the strut temperature distribution more uniform and caused the maximum temperature to decrease compared to standard transpiration cooling.</jats:p>

Journal article

Huang G, Zhu Y, Liao Z, Ouyang X-L, Jiang P-Xet al., 2017, Experimental investigation of transpiration cooling with phase change for sintered porous plates, International Journal of Heat and Mass Transfer, Vol: 114, Pages: 1201-1213, ISSN: 0017-9310

Journal article

Jiang P-X, Huang G, Zhu Y, Xu R, Liao Z, Lu Tet al., 2017, Experimental investigation of biomimetic self-pumping and self-adaptive transpiration cooling, Bioinspiration &amp; Biomimetics, Vol: 12, Pages: 056002-056002

Journal article

Jiang P-X, Huang G, Zhu Y, Liao Z, Huang Zet al., 2017, Experimental investigation of combined transpiration and film cooling for sintered metal porous struts, International Journal of Heat and Mass Transfer, Vol: 108, Pages: 232-243, ISSN: 0017-9310

Journal article

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