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  • 251. Xiao, Manxuan
    et al.
    Tang, Llewelly
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lun, Isaac Yu Fat
    Yuan, Yanping
    A Review on Recent Development of Cooling Technologies for Concentrated Photovoltaics (CPV) Systems2018Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 11, nr 12, artikkel-id 3416Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Concentrated Photovoltaics (CPV) technology, as an energy saving method which can directly generate electricity from the Sun, has attracted an ever-increasing attention with the deepening worldwide energy crisis. However, operating temperature is one of the main concerns that affect the CPV system. Excess cell temperature causes electrical conversion efficiency loss and cell lifespan decrease. Thus, reasonable cooling methods should decrease the operating temperature and balance the flare inhomogeneity. They also need to display high reliability, low power consumption, and convenient installation. This paper presented the architectural, commercial, and industrial usage of CPV system, reviewed the recent research developments of different cooling techniques of CPV systems during last few years, including the spectral beam splitting technology, cogeneration power technology, commonly used and promising cooling techniques, active and passive cooling methods. It also analysed the design considerations of the cooling methods in CPV systems, introduced the classification and basic working principles and provided a thorough compilation of different cooling techniques with their advantages, current research limitations, challenges, and possible further research directions. The aim of this work is to find the research gap and recommend feasible research direction of cooling technologies for CPV systems. 

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  • 252. Xiong, Y
    et al.
    Bo, L
    Qiang, M
    Wu, Y
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. University of Nottingham.
    Xu, P
    Ma, C
    A characteristic study on the start-up performance of molten-salt heat pipes: Experimental investigation2017Inngår i: Experimental Thermal and Fluid Science, ISSN 0894-1777, E-ISSN 1879-2286, Vol. 82, s. 433-438Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper reports a fundamental experimental investigation of the start-up characteristics of heat pipes using a dedicated molten-salt mixture as the working fluid. Based on four single salt, i.e. NaNO3(AR), KNO3(AR), LiNO3(AR) and Ca(NO3)2(AR), a quaternary molten-salt working fluid was developed and charged at different masses into four heat pipes with the same dimensions of 980 mm in length and 22 mm in diameter. A parallel comparison on the start-up performance of these heat pipes was then conducted to observe the influence of the charging mass and the inclination angle under the consistent lab-controlled conditions. The experimental results showed the heat pipe with molten-salt charge of 40 g responded much quicker than those with molten salt charge of 60 g, 70 g and 80 g respectively; meanwhile, the molten-salt heat pipe achieved the maximum condensation temperature at inclination angle of 50°. Comparing to the conventional naphthalene heat pipe, the dedicated molten-salt heat pipe had a much shorter start-up time when they were charged with the same amount of 40 g. The overall research result is expected to provide certain guidance for further design and operation of molten-salt heat pipe in high-and-medium-temperature heat transfer and storage scenarios. 

  • 253. Xu, Jihuan
    et al.
    Zhang, Xingxing
    A novel water heating system by low-temperature solar capillary heat pipe assisted with heat pump2012Patent (Annet (populærvitenskap, debatt, mm))
  • 254. Xu, Peng
    et al.
    Liu, Chenchen
    Zhang, Xingxing
    Tang, Llewellyn
    Numerical study on the thermal performance of earth-tube system for green building in Ningbo, China2016Konferansepaper (Fagfellevurdert)
  • 255. Xu, Peng
    et al.
    Shen, Jingchun
    University of Nottingham, Ningbo.
    Zhang, Xingxing
    University of Hull; University of Nottingham .
    He, Wei
    Zhao, Xudong
    Design, fabrication and experimental study of a novel loop-heat-pipe based solar thermal facade water heating system2015Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 566-571Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper investigated a novel loop-heat-pipe based solar thermal facade heat-pump system for hot water from concept design, prototype fabrication and experimental test. Given the specific testing conditions, the solar thermal efficiency of the facade module achieved nearly 0.71 in average and the mean system's COP was about 5.0. It is expected that such novel LHP based solar thermal facade technology would further contributed to the development of the renewable (solar) driven heating/hot water service and therefore lead to significant environmental benefits.

    Fulltekst (pdf)
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  • 256. Xu, Peng
    et al.
    Shen, Jingchun
    Zhang, Xingxing
    University of Hull; University of Nottingham.
    Zhao, Xudong
    Qian, Yingchu
    Case study of smart meter and in-home display for residential behavior change in Shanghai, China2015Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 2694-2699Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Smart meters and in-home displays (IHD) have been recently adopted to help give residential consumers more control over energy consumption, and to help meet environmental and security of supply objectives. The paper aims to identify the effectiveness of smart meters and real-time IHDs in reducing Shanghai household energy consumption through a pilot investigation. The research results demonstrate the improved awareness, understanding, and attitudes towards the energy saving by smart meters and IHDs.

  • 257. Xu, Peng
    et al.
    Zhang, Xingxing
    Shen, Jingchun
    Yang, Tong
    Deng, Wu
    Tang, Llewellyn
    Empirical study of the energy saving potentials in Shanghai residential buildings through human behaviour change2015Konferansepaper (Fagfellevurdert)
  • 258. Xu, Peng
    et al.
    Zhang, Xingxing
    University of Nottingham, Ningbo.
    Shen, Jingchun
    University of Nottingham, Ningbo.
    Yang, Tong
    Deng, Wu
    Tang, Llewellyn
    Empirical study of the energy saving potentials in Shanghai residential buildings through human behaviour change2015Konferansepaper (Fagfellevurdert)
  • 259. Xu, Peng
    et al.
    Zhang, Xingxing
    Shen, Jingchun
    University of Nottingham, Ningbo.
    Yang, Tong
    Tang, Llewellyn
    Comparative study of a novel thermal absorber based solar photovoltaic/thermal against photovoltaic system2015Konferansepaper (Fagfellevurdert)
  • 260. Xu, Peng
    et al.
    Zhang, Xingxing
    Shen, Jingchun
    Yang, Tong
    Tang, Llewellyn
    Field-experimental study of a novel solar photovoltaic/thermal (PV/T) system2015Konferansepaper (Fagfellevurdert)
  • 261. Xu, Peng
    et al.
    Zhang, Xingxing
    University of Hull.
    Shen, Jingchun
    University of Hull.
    Zhao, Xudong
    He, Wei
    Li, Deying
    Parallel experimental study of a novel super-thin thermal absorber based photovoltaic/thermal (PV/T) system against conventional photovoltaic (PV) system2015Inngår i: Energy Reports, ISSN 2050-0505, E-ISSN 2352-4847, Vol. 1, s. 30-35Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photovoltaic (PV) semiconductor degrades in performance due to temperature rise. A super thin-conductive thermal absorber is therefore developed to regulate the PV working temperature by retrofitting the existing PV panel into the photovoltaic/thermal (PV/T) panel. This article presented the parallel comparative investigation of the two different systems through both laboratory and field experiments. The laboratory evaluation consisted of one PV panel and one PV/T panel respectively while the overall field system involved 15 stand-alone PV panels and 15 retrofitted PV/T panels. The laboratory testing results demonstrated the PV/T panel could achieve the electrical efficiency of about 16.8% (relatively 5% improvement comparing with the stand-alone PV panel), and yield an extra amount of heat with thermal efficiency of nearly 65%. The field testing results indicated that the hybrid PV/T panel could enhance the electrical return of PV panels by nearly 3.5%, and increase the overall energy output by nearly 324.3%. Further opportunities and challenges were then discussed from aspects of different PV/T stakeholders to accelerate the development. It is expected that such technology could become a significant solution to yield more electricity, offset heating load freely and reduce carbon footprint in contemporary energy environment.

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  • 262.
    Yeneneh, Getu Temasgen
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Testing of Apis System Platform in Grid-Connected Photovoltaic System and Comparison with Metrum for Fault Detection and Diagnosis2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A real time data management web-based software-platform for PV plant monitoring called Apis was tested for fault detection and diagnosis of large scale grid-connected photovoltaic systems. This method was compared with Metrum system which is also another web based monitoring system used in grid connected PV systems. The objective of testing and comparisons were to observe the Apis system performance in large scale PV systems particularly for fault detection, and to identify which of the two systems could give more information to easily identify type of fault and point out the fault location in PV plants.

    The experiment were carried out in the selected two different arrays that have a capacity of 18.4kW and 17.6 kW with four string inverters each, to test three cases at Glava energy center solar park, Sweden. The first demonstrates the response of the systems when the wiring loose or cable disconnection fault occurs in the plant. The second demonstrates the output of the inverters when partial shading is gradually increased and the third demonstrates the output when the fault at components (i.e. at inverter, fuse and circuit breaker) is applied. Both systems collect data from inverters. However, in Apis system, data from individual inverters of the plant could be collected separately in both AC and DC sides while Metrum system was measuring the total output of the whole inverters in the plant.

    During the string disconnection, the Apis monitoring system showed a power drop to zero from the defected strings making it possible to identify them. In the same way during the inverters’ fault the power output of the failed inverter was dropped to zero. However, the normal strings and inverters were still working properly. Meanwhile the Metrum system only displayed a reduced power output which doesn’t directly identify the problem and requires manual inspection. In the case of partial shading there was a persistent difference occurred between the defected string and normal one but it did not dropped to zero at all.

    Apis system is able to differentiate and locate the faults by comparing input and output results of different inverters within the plant, unlike Metrum system which measures the total output of the plant. Nevertheless, Apis system still has less possibility to determine the type of fault further than estimation.

  • 263. Yuan, Y
    et al.
    Ouyang, L
    Sun, L
    Cao, X
    Xiang, B
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Effect of connection mode and mass flux on the energy output of a PVT hot water system2017Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 158, s. 285-294Artikkel i tidsskrift (Fagfellevurdert)
  • 264. Yuhan, Z.
    et al.
    Jinshun, W.
    Mu, L.
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lining, Z.
    Weiya, Z.
    Weijie, Z.
    Jun, W.
    Liang, X.
    Yixuan, W.
    Research on Operation Strategy of Solar Assisted Air Source Heat Pump System2019Inngår i: IOP Conference Series: Materials Science and Engineering, 2019, Vol. 56, nr 1, artikkel-id 012028Konferansepaper (Fagfellevurdert)
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  • 265. Zhang, Xingxing
    An Initial Concept Design of an Innovative Flat-Plate Solar Thermal Facade for Building Integration2015Konferansepaper (Fagfellevurdert)
  • 266.
    Zhang, Xingxing
    University of Nottingham.
    Investigation of a Cogeneration of Cooling/heating-electricity Supply Heat Pump System Based on PV/e Roof Module2010Inngår i: Building Energy & Environment, ISSN 1003-0344, Vol. 2, s. 56-58Artikkel i tidsskrift (Fagfellevurdert)
  • 267. Zhang, Xingxing
    Smart Meter and In-home Display Technology towards Sustainable Residential Development: Case Study of a Pilot Investigation in Shanghai2015Konferansepaper (Fagfellevurdert)
  • 268.
    Zhang, Xingxing
    et al.
    University of Nottingham.
    Jingshun, Shen
    Zehui, Hong
    Luying, Wang
    Tong, Yang
    Llewellyn, Tang
    Yupeng, Wu
    Yong, Shi
    Liang, Xia
    Shengchung, Liu
    Building integrated solar thermal (BIST) technologies and their applications: A review of structural design and architectural integration2015Inngår i: Journal of Fundamentals of Renewable Energy and Applications, ISSN 2090-4533, E-ISSN 2090-4541, Vol. 5, nr 5, s. 1-21Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Solar energy has enormous potential to meet the majority of present world energy demand by effective integration with local building components. One of the most promising technologies is building integrated solar thermal (BIST) technology. This paper presents a review of the available literature covering various types of BIST technologies and their applications in terms of structural design and architectural integration. The review covers detailed description of BIST systems using air, hydraulic (water/heat pipe/refrigerant) and phase changing materials (PCM) as the working medium. The fundamental structure of BIST and the various specific structures of available BIST in the literature are described. Design criteria and practical operation conditions of BIST systems are illustrated. The state of pilot projects is also fully depicted. Current barriers and future development opportunities are therefore concluded. Based on the thorough review, it is clear that BIST is very promising devices with considerable energy saving prospective and building integration feasibility. This review shall facilitate the development of solar driven service for buildings and help the corresponding saving in fossil fuel consumption and the reduction in carbon emission.

    Fulltekst (pdf)
    fulltext
  • 269. Zhang, Xingxing
    et al.
    Li, Guozhen
    Tang, Llewellyn
    Zhou, Tongyu
    A compact flat-plate heat pipe with ammonia water as working medium2017Patent (Annet (populærvitenskap, debatt, mm))
  • 270.
    Zhang, Xingxing
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lovati, Marco
    Vigna, Ilaria
    Widén, Joakim
    Han, Mengjie
    Högskolan Dalarna, Akademin Industri och samhälle, Mikrodataanalys.
    Gál, Csilla V
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Feng, Tao
    A review of urban energy systems at building cluster level incorporating renewable-energy-source (RES) envelope solutions2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 230, s. 1034-1056Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The emergence of renewable-energy-source (RES) envelope solutions, building retrofit requirements and advanced energy technologies brought about challenges to the existing paradigm of urban energy systems. It is envisioned that the building cluster approach—that can maximize the synergies of RES harvesting, building performance, and distributed energy management—will deliver the breakthrough to these challenges. Thus, this paper aims to critically review urban energy systems at the cluster level that incorporate building integrated RES solutions. We begin with defining cluster approach and the associated boundaries. Several factors influencing energy planning at cluster scale are identified, while the most important ones are discussed in detail. The closely reviewed factors include RES envelope solutions, solar energy potential, density of buildings, energy demand, integrated cluster-scale energy systems and energy hub. The examined categories of RES envelope solutions are (i) the solar power, (ii) the solar thermal and (iii) the energy-efficient ones, out of which solar energy is the most prevalent RES. As a result, methods assessing the solar energy potentials of building envelopes are reviewed in detail. Building density and the associated energy use are also identified as key factors since they affect the type and the energy harvesting potentials of RES envelopes. Modelling techniques for building energy demand at cluster level and their coupling with complex integrated energy systems or an energy hub are reviewed in a comprehensive way. In addition, the paper discusses control and operational methods as well as related optimization algorithms for the energy hub concept. Based on the findings of the review, we put forward a matrix of recommendations for cluster-level energy system simulations aiming to maximize the direct and indirect benefits of RES envelope solutions. By reviewing key factors and modelling approaches for characterizing RES-envelope-solutions-based urban energy systems at cluster level, this paper hopes to foster the transition towards more sustainable urban energy systems.

    Fulltekst (pdf)
    fulltext
  • 271.
    Zhang, Xingxing
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Pan, Song
    Wu, Jinshun
    Xia, Liang
    China leans balance to distributed solar-power projects: challenge and opportunities2017Konferansepaper (Fagfellevurdert)
  • 272.
    Zhang, Xingxing
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Pan, Song
    Wu, Jinshun
    Xia, Liang
    Recycling discarded shipping containers for reliable building envelopes: a design case for senior citizens in Solar Decathlon China 20172017Konferansepaper (Fagfellevurdert)
  • 273.
    Zhang, Xingxing
    et al.
    University of Nottingham.
    Shen, Jingchun
    Adkins, Deborah
    Yang, Tong
    Tang, Llewellyn
    Zhao, Xudong
    He, Wei
    Xu, Peng
    Liu, Chenchen
    Luo, Huizhong
    The early design stage for building renovation with a novel loop-heat-pipe based solar thermal facade (LHP-STF) heat pump water heating system: Techno-economic analysis in three European climates2015Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 106, s. 964-986Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Most of the building renovation plans are usually decided in the early design stage. This delicate phase contains the greatest opportunity to achieve the high energy performance buildings after refurbishment. It is therefore important to provide the pertinent energy performance information for the designers or decision-makers from multidisciplinary and comparative points of view. This paper investigates the renovation concept of a novel loop-heat-pipe based solar thermal facade (LHP-STF) installed on a reference residential building by technical evaluation and economic analysis in three typical European climates, including North Europe (represented by Stockholm), West Europe (represented by London) and South Europe (represented by Madrid). The aim of this paper is firstly to explore the LHP-STF’s sensitivity with regards to the overall building socio-energy performance and secondly to study the LHP-STF’s economic feasibility by developing a dedicated business model. The reference building model was derived from the U.S. Department of Energy (DOE) commercial buildings research, in which the energy data for the building models were from the ASHRAE codes and other standard practices. The financial data were collected from the European statistic institute and the cost of system was based on the manufactured prototype. Several critical financial indexes were applied to evaluate the investment feasibility of the LHP-STF system in building renovation, such as Payback Period (PP), Net Present Value (NPV), and the modified internal rate of return method (IRR). Four common investment options were considered in this business model, including buying outright (BO), buying by instalment (BI), energy efficiency funding (EEF) and power purchase agreement (PPA). The research results indicate that the LHP-STF could contribute to the hot water load throughout the year with substantially reduced heating load in winter, and yet a slight increased cooling load in summer. Among four investment options, the BO was considered as the best investment method with the highest NPV, IRR and the shortest payback period. With regards to relatively limited solar resources, London was found to be the best place for investment with the highest economical revenues and an attractive payback period of less than four years for all purchase options. Although Madrid has the richest solar resource, this system has the lowest economic profit and the longest payback period. This outcome confirms that the renewable energy incentives have a higher impact than solar resources on current solar thermal facade technologies under such pricing fundamentals. This multidisciplinary research is expected to be helpful for the strategic decisions at the early design stage for building renovation with the proposed system and further promote development of solar driven service system, leading to the savings in fossil fuel consumption and reduction in carbon emission.

  • 274.
    Zhang, Xingxing
    et al.
    University of Hull; University of Nottingham.
    Shen, Jingchun
    He, Wei
    Xu, Peng
    Zhao, Xudong
    Tan, Junyi
    Comparative study of a novel liquid-vapour separator incorporated gravitational loop heat pipe against the conventional gravitational straight and loop heat pipes - Part I: Conceptual development and theoretical analyses2015Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 90, s. 409-426Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aim of the paper is to investigate the thermal performance of a novel liquid–vapour separator incorporated gravity-assisted loop heat pipe (GALHP) (T1), against a conventional GALHP (T2) and a gravitational straight heat pipe (T3), from the conceptual and theoretical aspects. This involved a dedicated conceptual formation, thermo-fluid analyses, and computer modelling and results discussion. The innovative feature of the new GALHP lies in the integration of a dedicated liquid–vapour separator on top of its evaporator section, which removes the potential entrainment between the heat pipe liquid and vapour flows and meanwhile, resolves the inherent ‘dry-out’ problem exhibited in the conventional GALHP. Based on this recognised novelty, a dedicated steady-state thermal model covering the mass continuity, energy conservation and Darcy equations was established. The model was operated at different sets of conditions, thus generating the temperature/pressure contours of the vapour and liquid flows at the evaporator section, the overall thermal resistance, the effective thermal conductivity, and the flow resistances across entire loop. Comparison among these results led to determination of the optimum operational settings of the new GALHP and assessment of the heat-transfer enhancement rate of the new GALHP against the conventional heat pipes. It was suggested that the overall thermal resistance of the three heat pipes (T1, T2, and T3) were 0.10 °C/W, 0.49 °C/W and 0.22 °C/W, while their effective thermal conductivities were 31,365 W/°C m, 9,648 W/°C m and 5,042 W/°C m, respectively. This indicated that the novel heat pipe (T1) could achieve a significantly enhanced heat transport effect, relative to T2 and T3. Compared to a typical cooper rod, T1 has around 78 times higher effective thermal conductivity, indicating that T1 has the tremendous competence compared to other heat transfer components. It should be noted that this paper only reported the theoretical outcomes of the research and the second paper would report the follow-on experimental study and model validation. The research results could be directly used for design, optimisation and analyses of the new GALHP, thus promoting its wide applications in various situations to enable the enhanced thermal performance to be achieved.

  • 275.
    Zhang, Xingxing
    et al.
    University of Nottingham; University of Hull.
    Shen, Jingchun
    He, Wei
    Xu, Peng
    Zhao, Xudong
    Tan, Junyi
    Comparative study of a novel liquid-vapour separator incorporated gravitational loop heat pipe against the conventional gravitational straight and loop heat pipes - Part II: Experimental testing and simulation model validation2015Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 93, s. 228-238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aim of the paper is to report the experimental study of a novel liquid–vapour separator incorporated gravity-assisted loop heat pipe (GALHP) (T1), against the conventional GALHP (T2) and a gravitational straight heat pipe (T3). Based on the results derived from the theoretical analyses and computer modelling, three prototype heat pipes, one for each type, were designed, constructed and tested to characterise their thermal performance under a series of operational conditions. By using the experimental data, the computer simulation model reported in the authors’ previous paper was examined and analysed, indicating that the model could achieve a reasonable accuracy in predicting the thermal performance of the three heat pipes. Under the specifically defined testing condition, T1 has more evenly distributed axial temperature profile than the other two heat pipes (T2 and T3). The start-up timings for T1, T2 and T3 were 410 s, 1400 s and 390 s respectively, indicating that the heat transfer within T2 was affected by the larger evaporator dry-out surface area and restricted evaporation area. The overall thermal resistance of T1 was 0.11 °C/W, which was around 20% and 50% that of T2 and T3. The tested effective thermal conductivity in T1 was 29,968 W/°C m, which was 296% and 648% that of T2 and T3, and 7492% that of a standard copper rod. It is therefore concluded that the novel heat pipe (T1) could achieve a significantly enhanced heat transport effect, relative to T2, T3 and standard cooper rod. The experimental results derived from this research enabled characterisation of the thermal performance of T1, relative to other heat pipes, and validation of the developed computer simulation model derived from the authors’ previous research. These two parts researches in combination will enable design, optimisation and analyse of such a new GALHP, thus promoting its wide application and achieving efficient thermal management.

  • 276.
    Zhang, Xingxing
    et al.
    University of Hull.
    Shen, Jingchun
    Lu, Yan
    He, Wei
    Xu, Peng
    Zhao, Xudong
    Qiu, Zhongzhu
    Zhu, Zishang
    Zhou, Jinzhi
    Dong, Xiaoqiang
    Active Solar Thermal Facades (ASTFs): From concept, application to research questions2015Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 50, s. 32-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of the paper is to report a comprehensive review into a recently emerging building integrated solar thermal technology, namely, Active Solar Thermal Facades (ASTFs), in terms of concept, classification, standard, performance evaluation, application, as well as research questions. This involves the combined effort of literature review, analysis, extraction, integration, critics, prediction and conclusion. It is indicated that the ASTFs are sort of building envelope elements incorporating the solar collecting devices, thus enabling the dual functions, e.g., space shielding and solar energy collection, to be performed. Based on the function of the building envelopes, the ASTF systems can be generally classified as wall-, window-, balcony-and roof-based types; while the ASTFs could also be classified by the thermal collection typologies, transparency, application, and heat-transfer medium. Currently, existing building and solar collector standards are brought together to evaluate the performance of the ASTFs. The research questions relating to the ASTFs are numerous, but the major points lie in: (1) whole structure and individual components layout, sizing and optimisation; (2) theoretical analysis; (3) experimental measurement; and (4) energy saving, economic and environmental performance assessment. Based on the analysis of the identified research questions, achievements made on each question, and outstanding problems remaining with the ASTFs, further development opportunities on this topic are suggested: (1) development of an integrated database/software enabling both architecture design and engineering performance simulation; (2) real-time measurement of the ASTFs integrated buildings on a long-term scheme; (3) economic and environmental performance assessment and social acceptance analysis; (4) dissemination, marketing and exploitation strategies study. This study helps in identifying the current status, potential problems in existence, future directions in research, development and practical application of the ASTFs technologies in buildings. It will also promote development of renewable energy technology and thus contribute to achieving the UK and international targets in energy saving, renewable energy utilization, and carbon emission reduction in building sector.

  • 277.
    Zhang, Xingxing
    et al.
    University of Hull.
    Shen, Jingchun
    Xu, Peng
    Zhao, Xudong
    Xu, Ying
    Socio-economic performance of a novel solar photovoltaic/loop-heat-pipe heat pump water heating system in three different climatic regions2014Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 135, s. 20-34Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper aimed to study the socio-economic performance of a novel solar photovoltaic/loop-heat-pipe (PV/LHP) heat pump water heating system for application in three different climatic regions, namely, cold area represented by London, warm area represented by Shanghai, and hot (subtropical) area represented by Hong Kong. This study involved prediction of the annual fossil-fuel energy saving, investment return period and carbon emission reduction of the new system against the traditional gas-fired and electrical boilers based water heating systems. An established dynamic model developed by the authors was utilised to predict the system’s energy performance throughout a year in the three climatic regions. A life-cycle analytical model was further developed to analyse the economic and environmental benefits of the new system relative to the traditional systems. Analyses of the modelling results drew out several conclusive remarks: (1) the system could achieve the highest energy efficiency when operating at the hot (subtropical) climatic region (represented by Hong Kong), enabling the heat output of as high as 922 kW h/m2 yr and water temperature of above 45 °C, while the grid power input is only 59 kW h/m2 yr; (2) the system is worth for investment when operating at the high energy charging tariff area (represented by London), with the cost payback periods of 8 and 5 years relative to the traditional gas-fired and electrical boilers based systems, respectively; (3) the system could obtain the most promising environmental benefits when operating in Shanghai where the energy quality (embodied carbon volume of per kW h energy) is relatively poor, enabling reduction in life-cycle carbon emissions of around 4.08 tons/m2 and 17.87 tons/m2 respectively, relative to the gas-fired and electrical boilers. Answer to such a question on which area is most suitable for the system application is highly dependent upon the priority order among the three dominating factors: (1) energy efficiency, (2) economic revenue, and (3) environmental benefit, which may vary with the users, local concerns and policy influence, etc. The research results will be able to assist in decision making in implementation of the new PV/thermal technology and analyses of the associated economic and environmental benefits, thus contributing to realisation of the regional and global targets on fossil fuel energy saving and environmental sustainability.

  • 278. Zhang, Xingxing
    et al.
    Shen, Jingchun
    Yang, Tong
    Tang, Llewellyn
    Experimental study of a solar photovoltaic/thermal (PV/T) system2015Konferansepaper (Fagfellevurdert)
  • 279.
    Zhang, Xingxing
    et al.
    University of Nottingham.
    Shen, Jingchun
    University of Nottingham, Ningbo.
    Yang, Tong
    Tang, Llewellyn
    Wang, Luying
    Liu, Yingqi
    Xu, Peng
    Smart meter and in-home display for energy savings in residential buildings: a pilot investigation in Shanghai, China2019Inngår i: Intelligent Buildings International, ISSN 1750-8975, E-ISSN 1756-6932, Vol. 11, nr 1, s. 4-26Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Smart meters and in-home displays (IHDs) have been recently adopted to help give residential users more control over energy consumption, and meet environmental and supply security objectives. The article aims to identify the effectiveness and potential of smart meters and real-time IHDs in reducing Shanghai household energy consumption by affecting occupants? behaviour. A general landscape of the occupant behaviour in residential buildings was briefly painted. A pilot study in Shanghai with an effective sample of 131 respondents was arranged into two groups as IHD and non-IHD households. A dedicated statistical analysis model was developed based on the micro-level empirical data to investigate the characteristics and the regulations of electricity consumption in these two groups, such as check frequency, electricity consumption reduction and shifting, energy bill saving, and standby power. The research results demonstrate that IHDs could lead to around 9.1% reduction in monthly electricity consumption and about 11.0% cut off in monthly electricity bills. A general comparison of the electricity consumption reduction between this research and the average UK case was further made. Barriers at current stage and challenges for further work were finally discussed. The statistical model is expected to ?future proof? smart meter and real-time displays through macro-level designing in modularity and flexibility in China. The overall research initially proves the concept of the feasible impact of smart meter and display technologies in the Chinese context, which is further expected to contribute to the empirical evidence on how IHD feedback could influence household electricity consumption in the Chinese context.

  • 280. Zhang, Xingxing
    et al.
    Shen, Jingchun
    Yang, Tong
    Tang, Llewellyn
    Wu, Yupeng
    An initial concept design of an innovative flat-plate solar thermal facade for building integration2015Inngår i: Sustainable Buildings and Structures / [ed] Stephen P. Wilkinson, Jun Xia, Bing Chen, Taylor & Francis, 2015, s. 103-110Kapittel i bok, del av antologi (Fagfellevurdert)
  • 281.
    Zhang, Xingxing
    et al.
    University of Nottingham.
    Shen, Jingchun
    Yang, Tong
    Tang, Llewellyn
    Wu, Yupeng
    Pan, Song
    Wu, Jinshun
    Xu, Peng
    Assessment of the effectiveness of investment strategy in solar photovoltaic (PV) energy sector: a case study2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 2977-2982Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Solar photovoltaic (PV) energy is now promising to offer potential solutions for sustainable development, especially in China. A representative Chinese solar PV manufacturer - Shunfeng International Clean Energy Limited (SFCE) - is therefore assessed in this paper, including (1) investment strategies in China’s recent macroeconomic exposure; (2) the market exposure and vulnerability. The macroeconomic challenges in case of China’s continuous GDP growth would have significant implications for SFCE’s investment strategy. Although SFCE’s vulnerability is high, it has mediated its macro exposure and protect itself by advanced non-pricing competition, product/service differentiation, vertical and horizontal integration, and high-profit diversification etc. The research result is expected to offer useful indications for solar PV companies to adapt and succeed in the future energy industry and simultaneously help the world to mitigate climate change.

    Fulltekst (pdf)
    fulltext
  • 282. Zhang, Xingxing
    et al.
    Shen, Jingchun
    Zhao, Xudong
    Comparative investigation of solar photovoltaic (PV) and photovoltaic/thermal (PV/T) systems by both laboratory and field experiments2016Inngår i: Renewable Energy in the Service of Mankind Vol II: Selected Topics from the World Renewable Energy Congress WREC 2014 / [ed] Ali Sayigh, Springer, 2016Kapittel i bok, del av antologi (Fagfellevurdert)
  • 283. Zhang, Xingxing
    et al.
    Shen, Jingchun
    Zhao, Xudong
    Photovoltaic/Loop-Heat-Pipe Heat Pump Techno for Low-Carbon Buildings2014Bok (Fagfellevurdert)
  • 284.
    Zhang, Xingxing
    et al.
    University of Hull.
    Shen, Jingchun
    Zhao, Xudong
    Xu, ing
    Investigation of a Pilot-scale Photovoltaic/thermal System and its Opportunities for Future Development2014Inngår i: Open Journal of Renewable Energy and Sustainable Development, ISSN 2374-5371, Vol. 1, nr 2, s. 24-34Artikkel i tidsskrift (Fagfellevurdert)
  • 285. Zhang, Xingxing
    et al.
    Shen, Jingchun
    Zhao, Xudong
    Xu, Ying
    Nibeler, Benno
    A Pilot-scale Demonstration of a Novel Solar Photovoltaic/thermal (PV/T) System and its Scenarios for Future Development2014Konferansepaper (Fagfellevurdert)
  • 286. Zhang, Xingxing
    et al.
    Shen, Jingchun
    Zhao, Xudong
    Xu, Ying
    Nibeler, Benno
    Comparative Investigation of Solar Photovoltaic (PV) and Photovoltaic/thermal (PV/T) Systems2014Konferansepaper (Fagfellevurdert)
  • 287. Zhang, Xingxing
    et al.
    Shen, Jingchun
    Zhao, Xudong
    Xu, Ying
    Nibeler, Benno
    Investigation of a novel thermal absorber for retrofit of commercial photovoltaic panels2014Konferansepaper (Fagfellevurdert)
  • 288.
    Zhang, Xingxing
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Wei, Y.
    He, W.
    Qiu, Z.
    Zhao, Xiaoyun
    Högskolan Dalarna, Akademin Industri och samhälle, Mikrodataanalys.
    Solar Systems’ Economic and Environmental Performance Assessment2019Inngår i: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation / [ed] Xudong Zhao, Xiaoli Ma, Springer, 2019, s. 453-486Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The economic and environmental performance assessment of the solar system plays a critical role in building design, operation and retrofit. A dedicated economic model is necessary to assess the investment feasibility on a new technology, which allows investors to decide on a profitable investment, compare investment projects and know about the benefits of the best investment. An environmental model is adopted to predict carbon emission reduction in the solar system relative to the traditional heating and electronic systems. This chapter introduced three up-to-date solar system models and corresponding assessments related to their applications, including solar photovoltaic/loop heat pipe (PV/LHP) heat pump water heating system, loop heat pipe-based solar thermal facade (LHP-STF), heat pump water heating system as well as solar thermal facade (STF). The research results will be able to assist in decision-making in implementation of the proposed PV/T technology and analyses of the associated economic and environmental benefits, thus contributing to realization of regional and global targets on fossil fuel energy saving and environmental sustainability.

  • 289.
    Zhang, Xingxing
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Wu, J.
    Pan, S.
    Han, Mengjie
    Högskolan Dalarna, Akademin Industri och samhälle, Mikrodataanalys.
    An economic analysis of the solar photovoltaic/thermal (PV/T) technologies in Sweden: A case study2019Inngår i: IOP Conference Series: Materials Science and Engineering, 2019, Vol. 556, nr 1, artikkel-id 012002Konferansepaper (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 290.
    Zhang, Xingxing
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Wu, J
    Zhang, Y
    Pan, S
    Wei, Y
    Xia, L
    Zhang, W
    Numerical study on thermal performance of a gravity assisted loop heat pipe2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This article carried out a parametric study of the thermal performance of a novel gravity assisted loop heat pipe (GALHP)with composite mesh-screen wick structure. A refined three-way structure with interior liquid-vapour separator wasdeveloped on top of the evaporator to enable a gravity-assisted operation, which not only simplified the correspondingwick structure but also eliminated the ‘dry-out’ potential in conventional GALHPs. A dedicated simulation model wasdeveloped on basis of the heat transfer and the flow characteristics derived from the governing equations of mass, energyand momentum. The essential impact parameters to the GALHP thermal performance were further discussed. It was foundthat the GALHP thermal performance, represented by the reciprocal of overall thermal resistance, varies directly withapplied heat load, evaporator diameter, and vapour-liquid separator diameter. The research results would be useful fordesign, optimisation and application of such GALHP in the gravity-assisted circumstance for thermal management.

  • 291.
    Zhang, Xingxing
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Xiao, M.
    He, W.
    Qiu, Z.
    Zhao, Xiaoyun
    Högskolan Dalarna, Akademin Industri och samhälle, Mikrodataanalys.
    Heat Pump Technologies and Their Applications in Solar Systems2019Inngår i: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation / [ed] Xudong Zhao, Xiaoli Ma, Springer, 2019, s. 311-339Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    As the well known that global energy demand is on a trend of continuous growth, reducing energy demand and making good use of renewable energy are thought to be the major routes toward low carbon and sustainable future, in particular for the building sector. Compared to traditional gas-fired heating systems, heat pumps have been proved to be an energy-efficient heating technology which can save fossil fuel energy and consequently reduce CO2 emission. However, the most outstanding challenges for the application of heat pumps lie in their high demand for electrical power, and the insufficient heat transfer between the heat source and the refrigerant. To overcome these difficulties, a solar-assisted heat pump has been proposed to tackle these challenges. A solar-assisted heat pump combines a heat pump with a solar collector, enabling the use of solar energy to provide space heating and hot water for buildings. This chapter introduces heat pump technologies and their applications in solar systems. Two types of solar-assisted heat pump, direct and indirect expansion, are illustrated in details. This work has provided the fundamental research and experience for developing a solar heat pump system and contributing to a significant fossil fuel saving and carbon reduction in the global extent.

  • 292. Zhang, Xingxing
    et al.
    Xu, Peng
    Shen, Jingchun
    Tang, Llewellyn
    Hu, Di
    Xiao, Manxuan
    Wu, Yupeng
    Parametric study of a novel gravity assisted loop heat pipe (GALHP) with composite mesh-screen wick structure2016Konferansepaper (Fagfellevurdert)
  • 293. Zhang, Xingxing
    et al.
    Xu, Ying
    Xu, Jihuan
    A novel modular solar thermal facade2014Patent (Annet (populærvitenskap, debatt, mm))
  • 294. Zhang, Xingxing
    et al.
    Xu, Ying
    Xu, Jihuan
    A novel solar photovoltaic/thermal cogeneration system using the corrugated flat-plate thin-metal sheets2014Patent (Annet (populærvitenskap, debatt, mm))
  • 295. Zhang, Xingxing
    et al.
    Xu, Ying
    Xu, Jihuan
    A novel solar photovoltaic/thermal cogeneration system using the corrugated flat-plate thin-metal sheets2015Patent (Annet (populærvitenskap, debatt, mm))
  • 296. Zhang, Xingxing
    et al.
    Xu, Ying
    Xu, Jihuan
    A novel solar thermal absorber for integration of photovoltaic panels2014Patent (Annet (populærvitenskap, debatt, mm))
  • 297. Zhang, Xingxing
    et al.
    Xu, Ying
    Xu, Jihuan
    A novel thin-conductive solar thermal absorber and flat-plate solar collector2014Patent (Annet (populærvitenskap, debatt, mm))
  • 298.
    Zhang, Xingxing
    et al.
    De Montfort University.
    Zhao, X.
    Xu, J.
    Yu, X.
    Study of the heat transport capacity of a novel gravitational loop heat pipe2013Inngår i: International Journal of Low-Carbon Technologies, ISSN 1748-1317, E-ISSN 1748-1325, Vol. 8, nr 3, s. 210-223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article presented a theoretical analysis of the heat transfer limits associated with a gravitational loop heat pipe (LHP), which involves the utilization of an innovative liquid feeding/distributing and vapour/liquid-separating structure. The mathematical equations governing the heat transport capacity were applied to simulate several commonly known heat transfer limits of the pipe, namely, viscous, sonic, entrainment, capillary, boiling and liquid filling mass limits. This will allow the determination of the actual figure of the limitation and analyses of the factors effecting the limits, including the loop operational temperature, wick type, evaporator diameter/length, evaporator inclination angle, vapour column diameter in the three-way fitting, liquid filling mass and evaporator-to-condenser height difference. During the study, the heat-transfer limits associated with the three-way fitting for liquid feeding/distribution and vapour/liquid separation were given particular attention. The results derived from the analytical model indicated that the compound screen mesh wick can achieve better thermal performance over the sintered powder and open rectangular groove wicks. It was also found that the heat transport capacity of such LHP operation is positively proportional to the operational temperature, evaporator diameter, evaporator inclination angle, vapour column diameter within the three-way fitting, liquid filling mass and evaporator-to-condenser height difference, and in a reciprocal order to the evaporator length. With the specified loop configuration and operational conditions, the LHP can achieve a high heat transport capacity of around 900 W. Overall, the work presented in this article provided an approach to determine the heat transfer limitations for such a specific LHP operation that will be of practical use for the associated system design and performance evaluation. 

  • 299. Zhang, Xingxing
    et al.
    Zhao, Xudong
    Characterization of a Hybrid Photovoltaic/ Heat-Pump Water Heating System2012Inngår i: Proceeding 5th International Forum on Energy Saving and Environmental Protection Technologies for Air-Conditioning and Refrigeration, Beijing, China, 13th -14th June, 2012, 2012Konferansepaper (Fagfellevurdert)
  • 300. Zhang, Xingxing
    et al.
    Zhao, Xudong
    Shen, Jingchun
    Case study of a pilot-scale solar Photovoltaic/thermal (PV/T) system and its opportunities for future development2013Inngår i: Proceeding Portugal Sustainable Building 2013 (SB13) conference, Lisbon, Portugal, 30th Oct - 1st November, 2013, 2013Konferansepaper (Fagfellevurdert)
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