| 1. |
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| 2. |
- Han, Mengjie, 1985-, et al.
(författare)
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The reinforcement learning method for occupant behavior in building control : A review
- 2021
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Ingår i: Energy and Built Environment. - : Elsevier BV. - 2666-1233. ; 2:2, s. 137-148
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Tidskriftsartikel (refereegranskat)abstract
- Occupant behavior in buildings has been considered the major source of uncertainty for assessing energy consumption and building performance. Modeling frameworks are usually built to accomplish a certain task, but the stochasticity of the occupant makes it difficult to apply that experience to a similar but distinct environment. For complex and dynamic environments, the development of smart devices and computing power makes intelligent control methods for occupant behaviors more viable. It is expected that they will make a substantial contribution to reducing global energy consumption. Among these control techniques, the reinforcement learning (RL) method seems distinctive and applicable. The success of the reinforcement learning method in many artificial intelligence applications has given an explicit indication of how this method might be used to model and adjust occupant behavior in building control. Fruitful algorithms complement each other and guarantee the quality of the optimization. However, the examination of occupant behavior based on reinforcement learning methodologies is not well established. The way that occupant interacts with the RL agent is still unclear. This study briefly reviews the empirical applications using reinforcement learning, how they have contributed to shaping the modeling paradigms and how they might suggest a future research direction.
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| 3. |
- Huang, Pei, et al.
(författare)
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A review of data centers as prosumers in district energy systems : Renewable energy integration and waste heat reuse for district heating
- 2020
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 258
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Tidskriftsartikel (refereegranskat)abstract
- As large energy prosumers in district energy systems, on the one hand, data centers consume a large amount of electricity to ensure the Information Technologies (IT) facilities, ancillary power supply and cooling systems work properly; on the other hand, data centers produce a large quantity of waste heat due to the high heat dissipation rates of the IT facilities. To date, a systematic review of data centers from the perspective of energy prosumers, which considers both integration of the upstream green energy supply and downstream waste heat reuse, is still lacking. As a result, the potentials for improving data centers’ performances are limited due to a lack of global optimization of the upstream renewable energy integration and downstream waste heat utilization. This study is intended to fill in this gap and provides such a review. In this regard, the advancements in different cooling techniques, integration of renewable energy and advanced controls, waste heat utilization and connections for district heating, real projects, performance metrics and economic, energy and environmental analyses are reviewed. Based on the enormous amount of research on data centers in district energy systems, it has been found that: (1) global controls, which can manage the upstream renewable production, data centers’ operation and waste heat generation and downstream waste heat utilization are still lacking; (2) regional climate studies represent an effective way to find the optimal integration of renewable energy and waste heat recovery technologies for improving the data centers’ energy efficiency; (3) the development of global energy metrics will help to appropriately quantify the data center performances.
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| 4. |
- Huang, Pei, et al.
(författare)
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Investigation of the Peer-to-Peer energy trading performances in a local community under the future climate change scenario in Sweden
- 2022
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Ingår i: Energy Reports. - : Elsevier BV. - 2352-4847. ; 8, s. 989-1001
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Tidskriftsartikel (refereegranskat)abstract
- Peer-to-peer (P2P) energy sharing among neighboring households is a promising solution to mitigating the difficulties of renewable power (such as solar Photovoltaics (PV)) penetration on the power grid. Until now, there is still a lack of study on the impacts of future climate change on the P2P energy trading performances. The future climate change will cause variances in the renewable energy production and further lead to changes in the economic performances of households with various energy uses and affect the decision making in PV ownership and pricing strategies. Being unaware of these impacts could potentially hinder the P2P energy sharing application in practice. To bridge such knowledge gap, this paper conducts a systematic investigation of the climate change impacts on the energy sharing performance in solar PV power shared communities. The future weather data is generated using the Morphine method, and an agent-based modeling method is used for simulating the energy trading behaviors of households. Four comparative scenarios of different PV ownerships and pricing strategies are designed. The detailed energy trading performances (including the PV power self-sufficiency, cost saving, revenues, and compound annual growth rate) for the four comparative scenarios are analyzed under both the present and future climates and compared. The study results of a building community located in Sweden show that the future climate change is more beneficial to large energy use households while less beneficial to small households. High price of energy trading can improve the fairness of the economic performances in the community, especially when some of the households do not have any PV ownership. This study can help understand the future climate impacts on the energy sharing performances of building communities, which can in turn guide decision making in PV ownership and price setting for different households under the future climate change to facilitate real applications. © 2021 The Author(s)
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| 5. |
- Koke, Johannes, et al.
(författare)
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Strategies of Design Concepts and Energy Systems for NearlyZero‐Energy Container Buildings (NZECBs) inDifferent Climates
- 2021
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Ingår i: Buildings. - : MDPI AG. - 2075-5309. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- Container-based lightweight buildings offer a high ecologic and economic potential when they are designed as nearly zero-energy container buildings (NZECBs). Thus, they are relevant to energy transition in achieving an almost climate-neutral building stock. This paper describes and applies design strategies for suitable building concepts and energy systems to be used in NZECBs for different climates. Therefore, different applications in representative climatic zones were selected. Initially, the global climate zones were characterized and analyzed with regard to their potential for self-sufficiency and renewable energies in buildings. The design strategies were further developed and demonstrated for three cases: a single-family house in Sweden, a multi-family house in Germany, and a small school building in rural Ethiopia. For each case, design guidelines were derived and building concepts were developed. On the basis of these input data, various energy concepts were developed in which solar and wind energy, as well as biomass, were integrated as renewable energy sources. All the concepts were simulated and analyzed with the Polysun® software. The various approaches were compared and evaluated, particularly with regard to energy self-sufficiency. Self-sufficiency rates up to 80% were achieved. Finally, the influence of different climate zones on the energy efficiency of the single-family house was studied as well as the influence of the size of battery storage and insulation.
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| 6. |
- Lin, Jing, et al.
(författare)
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Human-Centric and Integrative Lighting Asset Management in Public Libraries : Insights and Innovations on Its Strategy and Sustainable Development
- 2024
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Ingår i: Sustainability. - : Multidisciplinary Digital Publishing Institute (MDPI). - 2071-1050. ; 16:5
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Tidskriftsartikel (refereegranskat)abstract
- In an era of rapidly advancing lighting technology and evolving public library roles, this study introduces a groundbreaking strategy for human-centric and integrative lighting asset management. Embracing both visual and non-visual effects, “integrative lighting” aims to enhance users’ physiological and psychological well-being. Despite technological progress, notably with LEDs, current asset management often lags, relying on reactionary measures rather than proactive strategies. As public libraries transform into dynamic learning hubs, the significance of indoor lighting, impacting both physical health and holistic well-being, cannot be understated. Yet, many existing solutions are based on controlled lab tests, bypassing the diverse real-world needs of public libraries. Aiming to explore and develop human-centric and integrative lighting asset management strategies to optimize lighting environments in public libraries, this research offers a cohesive approach encompassing context identification, a management framework, and a maturity assessment model. Additionally, this study highlights the synergy between the role of the lighting asset manager, ISO 55000 principles, and these foundational strategies. This holistic approach not only reinvents lighting in public libraries but also aligns it with the broader Sustainable Development Goals (SDGs), advocating for light as a conduit of comprehensive human betterment. The current study is primarily qualitative in nature. While this study is based on public libraries in Nordic countries, the implications and findings can be of interest and value to a broader international audience.
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| 7. |
- Lin, Jing, et al.
(författare)
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Human-Centric and Integrative Lighting Asset Management in Public Libraries : Qualitative Insights and Challenges From a Swedish Field Study
- 2024
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Ingår i: IEEE Access. - 2169-3536. ; 12, s. 40905-40921
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Tidskriftsartikel (refereegranskat)abstract
- Traditional reliability evaluation of lighting sources often assesses only 50% of a lamp’s volume, which can lead to performance disparities and misapplications due to their limited reflection of real-world scenarios. To address the limitations, it is essential to adopt advanced asset management approaches that enhance awareness and provide a more comprehensive evaluation framework. This paper delves into the nuances of human-centric and integrative lighting asset management in Swedish public libraries, employing a qualitative field study to ascertain the alignment of current practices with these advanced lighting principles. Expanding library services to 20 high-latitude locations (>55° N) in Sweden, our research employed field observations, stakeholder interviews, and questionnaires, coupled with a thorough gap analysis, to understand the current landscape and stakeholder perceptions. Our findings reveal a dichotomy between the existing conditions of library lighting and the stakeholders’ experiences and expectations. Despite the intention to create conducive environments, there is a clear disconnect, with overt problems and covert challenges affecting user satisfaction and efficacy of lighting management. Managers, staff, and users reported varied concerns, including eye strain and discomfort, indicative of substantial room for improvement. The study advocates for a paradigm shift in not only lighting asset management but also reliability evaluation of lighting sources, moving toward continuous improvement, and enhanced awareness and training on human-centric and integrative lighting principles.
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| 8. |
- Lin, Jing, et al.
(författare)
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Human-Centric and Integrative Lighting Asset Management in Public Libraries: Qualitative Insights and Challenges from a Swedish Field Study
- 2024
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers Inc.. - 2169-3536. ; 12, s. 40905-40921
-
Tidskriftsartikel (refereegranskat)abstract
- Traditional reliability evaluation of lighting sources often assesses only 50% of a lamp's volume, which can lead to performance disparities and misapplications due to their limited reflection of real-world scenarios. To address the limitations, it is essential to adopt advanced asset management approaches that enhance awareness and provide a more comprehensive evaluation framework. This paper delves into the nuances of human-centric and integrative lighting asset management in Swedish public libraries, employing a qualitative field study to ascertain the alignment of current practices with these advanced lighting principles. Expanding library services to 20 high-latitude locations (>55° N) in Sweden, our research employed field observations, stakeholder interviews, and questionnaires, coupled with a thorough gap analysis, to understand the current landscape and stakeholder perceptions. Our findings reveal a dichotomy between the existing conditions of library lighting and the stakeholders' experiences and expectations. Despite the intention to create conducive environments, there is a clear disconnect, with overt problems and covert challenges affecting user satisfaction and efficacy of lighting management. Managers, staff, and users reported varied concerns, including eye strain and discomfort, indicative of substantial room for improvement. The study advocates for a paradigm shift in not only lighting asset management but also reliability evaluation of lighting sources, moving toward continuous improvement, and enhanced awareness and training on human-centric and integrative lighting principles.
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| 9. |
- McKay, James D., et al.
(författare)
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A Genome-Wide Association Study of Upper Aerodigestive Tract Cancers Conducted within the INHANCE Consortium
- 2011
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 7:3
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have been successful in identifying common genetic variation involved in susceptibility to etiologically complex disease. We conducted a GWAS to identify common genetic variation involved in susceptibility to upper aero-digestive tract (UADT) cancers. Genome-wide genotyping was carried out using the Illumina HumanHap300 beadchips in 2,091 UADT cancer cases and 3,513 controls from two large European multi-centre UADT cancer studies, as well as 4,821 generic controls. The 19 top-ranked variants were investigated further in an additional 6,514 UADT cancer cases and 7,892 controls of European descent from an additional 13 UADT cancer studies participating in the INHANCE consortium. Five common variants presented evidence for significant association in the combined analysis (p <= 5 x 10(-7)). Two novel variants were identified, a 4q21 variant (rs1494961, p = 1 x 10(-8)) located near DNA repair related genes HEL308 and FAM175A (or Abraxas) and a 12q24 variant (rs4767364, p = 2 x 10(-8)) located in an extended linkage disequilibrium region that contains multiple genes including the aldehyde dehydrogenase 2 (ALDH2) gene. Three remaining variants are located in the ADH gene cluster and were identified previously in a candidate gene study involving some of these samples. The association between these three variants and UADT cancers was independently replicated in 5,092 UADT cancer cases and 6,794 controls non-overlapping samples presented here (rs1573496-ADH7, p = 5 x 10(-8); rs1229984-ADH1B, p = 7 x 10(-9); and rs698-ADH1C, p = 0.02). These results implicate two variants at 4q21 and 12q24 and further highlight three ADH variants in UADT cancer susceptibility.
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| 10. |
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| 11. |
- Shen, Jingchun, et al.
(författare)
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A Critical Review of Lighting Design and Asset Management Strategies. Illuminating Practices and Lessons Learned for Swedish Public Libraries
- 2023
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Ingår i: Journal of Physics, Conference Series. - : Institute of Physics (IOP). - 1742-6588 .- 1742-6596. ; 2654:1
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Konferensbidrag (refereegranskat)abstract
- Most lighting is only designed to meet the visual needs in most public library environments in Sweden. Although lighting-related impacts are relevant to six Unite Nations sustainability goals, some important lighting considerations, such as circadian phase disruption, mode and productivity impact, and energy-efficient operation, are missing in current lighting operating practices. Moreover, most of the current lighting asset management practice in public buildings remains "fix it if only it breaks". With respect to people-centric health factors, visual index, and lighting asset energy-efficient operation, this study sublimates lighting into a new perspective. Finally, the suggested comprehensive lighting operating strategies integrating digital twins can help designers and operators in defining the optimal design/control strategy in public-built environments, like public library. Digital twin-based decision-making is expected to be applied to lighting design and control in public spaces that improves visual acuity and comfort, positively impact mood and productivity, and provides recommendations on engagement principles under Environment Social Governance (ESG) framework to asset manager/operators.
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| 12. |
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| 13. |
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| 14. |
- Shen, Jingchun, et al.
(författare)
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Characteristic study of a novel compact Solar Thermal Facade (STF) with internally extruded pin-fin flow channel for building integration
- 2016
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 168, s. 48-64
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Tidskriftsartikel (refereegranskat)abstract
- The fully building integrated Solar Thermal Facade (STF) systems can become potential solutions for aesthetics architectural design, as well as for the enhancement of energy efficiency and reduction of operational cost in the contemporary built environment. As a result, this article introduces a novel compact STF with internally extruded pin–fin flow channel that is particularly suitable for the building integration. A dedicated simulation model was developed on basis of the heat transfer and the flow mechanics. A prototype of this STF was fabricated and then it was tested under a series of controlled environmental conditions. The experimental validation illustrated a good agreement with the simulation results, indicating the established model was able to predict the STF’s thermal performance at a reasonable accuracy (i.e. mean deviation of less than 5.46%). The impacts of several operational parameters, i.e. equivalent solar radiation, air temperature, air velocity, water mass flow rate and inlet water temperature, on the STF thermal performance were then discussed respectively. Given the baseline testing condition, the collector efficiency factor F′ is almost 0.9930, leading to a relatively high nominal thermal efficiency at about 63.21%, which demonstrates such STF, with simpler structure, lower cost and higher feasibility in architectural design, can achieve an equivalent or better thermal performance than recent bionic STF or the conventional ones. It is also concluded that the thermal efficiency varies proportionally with solar radiation, air temperature, and mass flow rate of water, but oppositely to air velocity and inlet water temperature. A sharp decreasing trend of this STF’s thermal efficiency against the (Tin − Ta)/I was observed under the given operational conditions, which indicates current STF design is only suitable for pool heating, domestic hot water and radiant space heating in areas/climates with warm ambient air temperature and sufficient solar radiation. The overall research results are beneficial for further design, optimization and application of such STF in various solar driven systems, including the provision of hot water, space heating/cooling, increased ventilation, or even electricity in buildings. Such STF technology has the potential to boost the building energy efficiency and literally turn the envelope into an independent energy plant, creating the possibility of solar-thermal technologies deployment in high-rise buildings.
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| 15. |
- Shen, Jingchun, et al.
(författare)
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Conceptual development of a compact unglazed Solar Thermal Facade (STF) for building integration
- 2016
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 96, s. 42-54
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Tidskriftsartikel (refereegranskat)abstract
- This research aims to develop an initiative modular unglazed Solar Thermal Facade (STF) concept initially for hot water generation to facilitate the integration of solar energy with buildings. The new STF concept is simple structure, low cost, and aesthetically appealing with easy installation but is expected to achieve the equivalent thermal efficiency as the conventional STFs. It delivered alternative design in terms of material, colour, texture, shape, size, architectural design, installation method, array connection, hypothetical system application, and solar coverage. Two common design variants i.e. (a) the STF cladding system and (b) the prefabricated STF wall system were described respectively for existing and new low-rise building typologies. Interaction of inclination, orientation, and insolation were discussed for the optimum STF position on the building. Four currently available methods for installation of such STF with buildings were summarized and three typical array connection methods were identified. The decentralized connection was recommended for different types of STF hot water systems. It is customary to design for a solar coverage of 50 to 60 percent for water heating in detached houses; in apartment buildings 30 to 40 percent are more commonly assumed. The concept design in this paper hereby illustrates the precedence for the hypothetical function by the creation of new ideas and also forms up the physical structure or operating principle for the investigations in near future.
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| 16. |
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| 17. |
- Shen, Jingchun, et al.
(författare)
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Design strategy of a compact unglazed solar thermal facade (STF) for building integration based on BIM concept
- 2017
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 105, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses the specific design strategy of a novel compact unglazed Solar Thermal Facade (STF) for building performance research in architectural practice. It identifies the basic role of such STF in the building performance simulation and analysis. A dedicated design strategy based on the BIM (building information modelling) concept for application of the proposed STF is then developed in details. This research work clarifies the necessary steps in ensuring that the environmental/economic factors and energy-efficiency strategies of the STF are integrated with the building design and analysis process at the early stage.
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| 18. |
- Shen, Jingchun, et al.
(författare)
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Enhancing Indoor Environmental Quality and Sustainability in Post-Pandemic Office Settings : A Study on Displacement Ventilation Feasibility
- 2023
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Ingår i: Buildings. - 2075-5309. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- The COVID-19 pandemic has catalyzed global efforts toward transitioning to a sustainable society, driving rapid innovation in building technologies, working practices, building design, and whole life cycle environmental impact consideration. In this pursuit, this study explores the enduring impact of these on an alternative ventilation approach for both existing building renovations and new building implementations. Comparing displacement ventilation to mixed-mode ventilation in a Finnish office building with varying occupancy densities, this study examines indoor air quality (IAQ), thermal comfort, total building energy performance, and embodied carbon. The findings reveal that the basic case of mixed ventilation has a specified system primary energy value of 38.83 kWh/m2 (with 28 occupants) and 39.00 kWh/m2 (with 24 occupants), respectively. With the displacement ventilation alternative, it reduces this by 0.3% and 0.1%, enhancing thermal comfort and decreasing turbulence as well as having a marginal decrease in embodied carbon. In general, the study offers three-fold contributions: insights into post-pandemic office mechanical ventilation design with an emphasis on sustainability and ecological footprint considerations, a concrete case study addressing climate action and human-centric IAQ design, and a multifaceted analysis using the Environmental, Social, and Governance (ESG) paradigm, contributing to the groundwork for associated future research and policy progress.
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| 19. |
- Shen, Jingchun, et al.
(författare)
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Experimental study of a compact unglazed Solar Thermal Facade (STF) for energy-efficient buildings
- 2016
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 104, s. 3-8
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a real-time experimental measurement of a novel compact unglazed solar thermal facade (STF) system at outdoor environment in Shanghai, China for about a whole summer week. It demonstrates the daily average solar thermal efficiency fluctuated from 40% to 45.5%. The overall result indicates the advantages of the STF with simple structure, low cost and high feasibility in architectural design for energy-efficient building application, especially at future district or city levels.
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| 20. |
- Shen, Jingchun, et al.
(författare)
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Exploring the potential of climate-adaptive container building design under future climate scenarios in three different climate zones
- 2020
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- The deployment of containers as building modules has grown in popularity over the past years due to their inherent strength, modular construction and relatively low cost. The upcycled container architecture is being accepted since it is more eco-friendly than using the traditional building materials with intensive carbon footprint. Moreover, owing to the unquestionable urgency of climate change, existing climate-adaptive design strategies may no longer respond effectively as they are supposed to work in the previous passive design. Therefore, this paper explores an adaptive upcycled strategy of shipping containers as a carbon-smart modular living solution to a single family house under three design scenarios related to cold, temperate and hot-humid climatic zones, respectively. By assessing the projected future climate data with the ASHRAE Standard 55 and Current Handbook of Fundamentals Comfort Model, it was found that Rome would gradually face more failures in conventional climate adaptive design measures in the coming 60 years. The appropriate utilization of internal heat gains seems to be the most promising measure in Rome, followed by the measure of windows sun shading and passive solar direct gain by using low mass. Weather analysis shows different results in Berlin and Stockholm, where special attention should be paid to the occasional overheating risk. As a result, the holistic climate-adaptive container building design measures are finally summarized from aspects of design features, production / process and challenges in implementation.
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| 21. |
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| 22. |
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| 23. |
- Shen, Jingchun, et al.
(författare)
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Offerings and challenges of demand response ventilation under covid-19 scenarios
- 2022
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Ingår i: Proceedings of the 17th IBPSA Conference Bruges, Belgium, Sept. 1-3, 2021. - : International Building Performance Simulation Association. - 9781775052029 ; , s. 2368-2373
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Konferensbidrag (refereegranskat)abstract
- Owning to the outbreak of COVID-19, individuals have to spend more time indoor. It is therefore essential to prepare for a long-term healthy indoor working environment in the transition of post COVID-19 pandemic. However, there is no relevant research so far in investigating such crisis impacts around indoor environmental quality and economic-health issues while home offices are expected becoming common practice soon. Therefore, a case of single-family house in Sweden is specially investigated using IDA ICE. By comparing four predominant ventilation approaches, three operational schedules are proposed, covering different confinement for occupants. Main results show that the demand response ventilation (DRV) generally should sacrifice in remarkable performance in energy saving, and emission reduction to better confront with more challenges in indoor air quality, occupied thermal dissatisfaction fraction and air stagnation under the challenge of COVID-19 pandemic scenario. Altered ventilation strategy should be customized from increased outdoor air supply, various demand-control signal, displacement method towards a heathier homeworking environment. © International Building Performance Simulation Association, 2022
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| 24. |
- Shen, Jingchun, et al.
(författare)
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Optimizing the configuration of a compact thermal facade module for solar renovation concept in buildings
- 2016
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 104, s. 9-14
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Tidskriftsartikel (refereegranskat)abstract
- Solar concepts show potentially an improved cost-performance (energy) ratio when applied as the integrated parts of building renovations. This paper reported a compact solar thermal facade (STF) module with the internally extruded flow channel suiting for solar renovation concept in buildings. A few of impact factors were considered for the parametric study in order to optimize the STF's configuration for various applications through the validated simulation model. The overall research results are expected to be useful for further improvement in the thermal performance of solar renovation measures.
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| 25. |
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| 26. |
- Shen, Jingchun, et al.
(författare)
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The early design stage of a novel Solar Thermal Facade (STF) for building integration : Energy performance simulation and socio-economic analysis
- 2016
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 96, s. 55-66
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a feasibility study of a new solar thermal façade (STF) concept for building integration from both technical and economic aspects in Shanghai area of China. The whole set of technical evaluation and economic analysis was investigated through simulation of a reference DOE residential building model in IES-VE software and a dedicated dynamic business model consisting of several critical financial indexes. In order to figure out the cost effectiveness of the STF concept, research work consisted of: (1) exploring the overall feasibility, i.e. energy load, energy savings, operational cost and environmental benefits, and (2) investigating the financial outputs for investment decisions within three different purchase methods. This paper presents a multidisciplinary research method that is expected to be beneficial and supportive for the strategic decision at the early design stage and it also offers a different angle to assess the economic performance of the STF application.
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| 27. |
- Wu, J., et al.
(författare)
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A review of thermal absorbers and their integration methods for the combined solar photovoltaic/thermal (PV/T) modules
- 2017
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 75, s. 839-854
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Tidskriftsartikel (refereegranskat)abstract
- Thermal absorbers and their integration methods are critical to solar photovoltaic/thermal (PV/T) modules. These two elements directly influence the cooling effort of PV layers and as a result, the related electrical/thermal/overall efficiency. This paper conducts a critical review on the essential thermal absorbers and their integration methods for the currently-available PV modules for the purpose of producing the combined PV/T modules. A brief overview of different PV/T technologies is initially summarized, including aspects of their structure, efficiencies, thermal governing expressions and their applications. Seven different types of thermal absorbers and four corresponding integration methods are subsequently discussed and summarized in terms of their advantages/disadvantages and the associated application for various PV/T modules. Compared to traditional thermal absorbers, such as sheet-and-tube structure, rectangular tunnel with or without fins/grooves and flat-plate tube, these four types, i.e. micro-channel heat pipe array/heat mat, extruded heat exchanger, roll-bond heat exchanger and cotton wick structure, are promising due to the significant enhancement in terms of efficiency, structure, weight, and cost etc. The appropriate or suitable integration method varies in different cases, i.e. the ethylene-vinyl acetate (EVA) based lamination method seems the best option for integration of PV layer with thermal absorber when compared with other conventional methods, such as direct contact, thermal adhesive and mechanical fixing. Finally, suggestions for further research topics are proposed from five aspects. The overall research results would provide useful information for the assistance of further development of solar PV/T modules with high feasibility for widespread application in energy supply even at district or city-level in the near future. © 2016 Elsevier Ltd.
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| 28. |
- Xu, Peng, et al.
(författare)
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Case study of smart meter and in-home display for residential behavior change in Shanghai, China
- 2015
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 75, s. 2694-2699
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 29. |
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| 30. |
- Xu, Peng, et al.
(författare)
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Design, fabrication and experimental study of a novel loop-heat-pipe based solar thermal facade water heating system
- 2015
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 75, s. 566-571
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 31. |
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| 32. |
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| 33. |
- Xu, Peng, et al.
(författare)
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Parallel experimental study of a novel super-thin thermal absorber based photovoltaic/thermal (PV/T) system against conventional photovoltaic (PV) system
- 2015
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Ingår i: Energy Reports. - : Elsevier BV. - 2352-4847. ; 1, s. 30-35
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Tidskriftsartikel (refereegranskat)abstract
- 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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| 34. |
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| 35. |
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| 36. |
- Zhang, Xingxing, et al.
(författare)
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A Preliminary Simulation Study About the Impact of COVID-19 Crisis on Energy Demand of a Building Mix at a District in Sweden
- 2023
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Ingår i: Future Urban Energy System for Buildings. - Singapore : Springer Nature. - 9789819912216 - 9789819912223 ; , s. 49-87
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The COVID-19 outbreak is exacerbating uncertainty in energy demand. This chapter aims to investigate the impact of the confined measures due to COVID-19 outbreak on energy demand of a building mix in a district. Three levels of confinement for occupant schedules are proposed based on a new district design in Sweden. The Urban Modeling Interface tool is applied to simulate the energy performance of the building mix. The boundary conditions and input parameters are set up according to the Swedish building standards and statistics. The district is at early design stage, which includes a mix of building functions, i.e., residential buildings, offices, schools, and retail shops. By comparing with the base case (normal life without confinement measures), the average delivered electricity demand of the entire district increases in a range of 14.3–18.7% under the three confinement scenarios. However, the mean system energy demands (sum of heating, cooling, and domestic hot water) decrease in a range of 7.1–12.0%. These two variation nearly cancel each other out, leaving the total energy demand almost unaffected. The result also shows that the delivered electricity demands in all cases have a relatively smooth variation across a year, while the system energy demands follow the principle trends for all the cases, which have peak demands in winter and much lower demands in transit seasons and summer. This chapter represents a first step in the understanding of the energy performance for community buildings when they confront with this kind of shock. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.
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| 37. |
- Zhang, Xingxing, et al.
(författare)
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Active Solar Thermal Facades (ASTFs) : From concept, application to research questions
- 2015
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 50, s. 32-63
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 38. |
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| 39. |
- Zhang, Xingxing, et al.
(författare)
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Assessment of the effectiveness of investment strategy in solar photovoltaic (PV) energy sector : a case study
- 2017
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 105, s. 2977-2982
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 40. |
- Zhang, Xingxing, et al.
(författare)
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Building integrated solar thermal (BIST) technologies and their applications : A review of structural design and architectural integration
- 2015
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Ingår i: Journal of Fundamentals of Renewable Energy and Applications. - : OMICS Publishing Group. - 2090-4533 .- 2090-4541. ; 5:5, s. 1-21
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 41. |
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| 42. |
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| 43. |
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| 44. |
- Zhang, Xingxing, et al.
(författare)
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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 analyses
- 2015
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 90, s. 409-426
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 45. |
- Zhang, Xingxing, et al.
(författare)
-
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 validation
- 2015
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 93, s. 228-238
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 46. |
- Zhang, Xingxing, et al.
(författare)
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Design, fabrication and experimental study of a solar photovoltaic/loop-heat-pipe based heat pump system
- 2013
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Ingår i: Solar Energy. - : Elsevier BV. - 0038-092X .- 1471-1257. ; 97, s. 551-568
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a novel solar photovoltaic/loop-heat-pipe (PV/LHP) module-based heat pump system was designed and fabricated for both electricity and hot water generation. A coated aluminium-alloy (Al-alloy) sheet was applied as the baseboard of PV cells for enhanced heat dissipation to the surroundings, which was characterised by a series of laboratory-controlled conditions over the conventional Tedlar–Polyester–Tedlar (TPT) baseboard. The whole prototype system was subsequently evaluated in outdoor weather conditions throughout a consecutive period for about one week. Impact of several external parameters to the PV panel with different baseboards was discussed and the results showed that weaker incident radiation, lower air temperature, higher wind speed, and ground mounting solution, were propitious to the PV electrical performance. Given the specific indoor testing conditions, temperature of the Al-alloy based PV cells was observed at about 62.4 °C, which was 5.2 °C lower than that of the TPT based PV cells, and its corresponding PV efficiency was about 9.18%, nearly 0.26% higher than the TPT based type. During the outdoor testing, the mean daily electrical, thermal and overall energetic and exergetic efficiencies of the PV/LHP module were measured at 9.13%, 39.25%, 48.37% and 15.02% respectively. The basic-thermal system performance coefficient (COPth) was found at 5.51 and the advanced system performance coefficient (COPPV/T) was nearly 8.71. A simple comparison was also conducted between the PV/LHP based heat-pump system and those conventional solar/air energy systems, which indicated that this advanced system harvests larger amount of solar energy and therefore enables enhanced solar efficiency and system performance. Basic analysis into the economic and environmental benefits of this prototype system further demonstrated such technology will be competitive in the future energy supply industry with a payback period of 16 (9) years and a life-cycle carbon reduction of 12.06 (2.94) tons in Shanghai (London).
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| 47. |
- Zhang, Xingxing, et al.
(författare)
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Digital Twin for Accelerating Sustainability in Positive Energy District : A Review of Simulation Tools and Applications
- 2021
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Ingår i: Frontiers in Sustainable Cities. - : Frontiers Media SA. - 2624-9634. ; 3
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Forskningsöversikt (refereegranskat)abstract
- A digital twin is regarded as a potential solution to optimize positive energy districts (PED). This paper presents a compact review about digital twins for PED from aspects of concepts, working principles, tools/platforms, and applications, in order to address the issues of both how a digital PED twin is made and what tools can be used for a digital PED twin. Four key components of digital PED twin are identified, i.e., a virtual model, sensor network integration, data analytics, and a stakeholder layer. Very few available tools now have full functions for digital PED twin, while most tools either have a focus on industrial applications or are designed for data collection, communication and visualization based on building information models (BIM) or geographical information system (GIS). Several observations gained from successful application are that current digital PED twins can be categorized into three tiers: (1) an enhanced version of BIM model only, (2) semantic platforms for data flow, and (3) big data analysis and feedback operation. Further challenges and opportunities are found in areas of data analysis and semantic interoperability, business models, data security, and management. The outcome of the review is expected to provide useful information for further development of digital PED twins and optimizing its sustainability.
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| 48. |
- Zhang, Xingxing, et al.
(författare)
-
Dynamic performance of a novel solar photovoltaic/loop-heat-pipe heat pump system
- 2014
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 114, s. 335-352
-
Tidskriftsartikel (refereegranskat)abstract
- Objective of the paper is to present an investigation into the dynamic performance of a novel solar photovoltaic/loop-heat-pipe (PV/LHP) heat pump system for potential use in space heating or hot water generation. The methods used include theoretical computer simulation, experimental verification, analysis and comparison. The fundamental equations governing the transient processes of solar transmission, heat transfer, fluid flow and photovoltaic (PV) power generation were appropriately integrated to address the energy balances occurring in different parts of the system, e.g., glazing cover, PV cells, fin sheet, loop heat pipe, heat pump cycle and water tank. A dedicated computer model was developed to resolve the above grouping equations and consequently predict the system’s dynamic performance. An experimental rig was constructed and operated under the real weather conditions for over one week in Shanghai to evaluate the system living performance, which was undertaken by measurement of various operational parameters, e.g., solar radiation, photovoltaic power generation, temperatures and heat pump compressor consumption. On the basis of the first- (energetic) and second- (exergetic) thermodynamic laws, an overall evaluation approach was proposed and applied to conduct both quantitative and qualitative analysis of the PV/LHP module’s efficiency, which involved use of the basic thermal performance coefficient (COPth) and the advanced performance coefficient (COPPV/T) of such a system. Moreover, a simple comparison between the PV/LHP heat-pump system and conventional solar/air energy systems was conducted. The research results indicated that under the testing outdoor conditions, the mean daily electrical, thermal and overall energetic and exergetic efficiencies of the PV/LHP module were 9.13%, 39.25%, 48.37% and 15.02% respectively, and the average values of COPth and COPPV/T were 5.51 and 8.71. The PV/LHP module was found to achieve 3–5% higher solar exergetic efficiency than standard PV systems and about 7% higher overall solar energetic efficiency than the independent solar collector. Compared to the conventional solar/air heat pump systems, the PV/LHP heat pump system could achieve a COP figure that is around 1.5–4 times that for the conventional systems. It is concluded that the computer model is able to achieve a reasonable accuracy in predicting the system’s dynamic performance. The PV/LHP heat pump system is able to harvest significant amount of solar heat and electricity, thus enabling achieving enhanced solar thermal and electrical efficiencies. All these indicate a positive implication that the proposed system has potential to be developed into a high performance PV/T technology that can contribute to significant fossil fuel energy saving and carbon emission.
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| 49. |
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| 50. |
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