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Zhao, Xiaoyun, Ph.D.ORCID iD iconorcid.org/0000-0002-7512-5321
Publications (10 of 20) Show all publications
Zhang, X., Xiao, M., He, W., Qiu, Z. & Zhao, X. (2019). Heat Pump Technologies and Their Applications in Solar Systems. In: Xudong Zhao, Xiaoli Ma (Ed.), Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation: (pp. 311-339). Springer
Open this publication in new window or tab >>Heat Pump Technologies and Their Applications in Solar Systems
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2019 (English)In: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation / [ed] Xudong Zhao, Xiaoli Ma, Springer, 2019, p. 311-339Chapter in book (Refereed)
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.

Place, publisher, year, edition, pages
Springer, 2019
Series
Green Energy and Technology
Keywords
Heat pump, PV, Loop heat pipe, Micro-channels-evaporator, Performance
National Category
Energy Engineering
Research subject
Energy and Built Environments
Identifiers
urn:nbn:se:du-30577 (URN)10.1007/978-3-030-17283-1_9 (DOI)2-s2.0-85068761593 (Scopus ID)978-3-030-17282-4 (ISBN)978-3-030-17283-1 (ISBN)
Available from: 2019-07-24 Created: 2019-07-24 Last updated: 2019-07-24Bibliographically approved
Zhang, X., Wang, X. & Zhao, X. (2019). Solar System Design and Energy Performance Assessment Approaches. In: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation: (pp. 417-451). Springer
Open this publication in new window or tab >>Solar System Design and Energy Performance Assessment Approaches
2019 (English)In: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation, Springer, 2019, p. 417-451Chapter in book (Refereed)
Abstract [en]

Recently, solar system has gained a rapid development in many countries because it is clean and sustainable. Many solar systems including the solar photovoltaic/loop-heat-pipe (PV/LHP), solar loop-heat-pipe (LHP), solar photovoltaic/micro-channel heat pipe (PV/MCHP) system, and solar thermal facade system (STF) have been designed for energy saving. To assess these systems’ performance, there are many approaches such as energy and exergy assessment which is used in this chapter to analyze their performance. Besides the system design, the authors set up dedicated experimental models in combination with computer models to test the systems’ performance. Furthermore, some systems are compared with the conventional system, and the performance of these solar systems is better than the conventional system. In addition, these solar systems are applied in many real buildings and their performance is examined, the results show that the solar systems have more potential to boost the building energy efficiency and create the possibility of solar development in buildings. © 2019, Springer Nature Switzerland AG.

Place, publisher, year, edition, pages
Springer, 2019
Series
Green Energy and Technology
Keywords
Energy and exergy, LHP, Performance assessment, PV/LHP, PV/MCHP, STF
National Category
Environmental Analysis and Construction Information Technology
Research subject
Energy and Built Environments
Identifiers
urn:nbn:se:du-30573 (URN)10.1007/978-3-030-17283-1_12 (DOI)2-s2.0-85068790412 (Scopus ID)978-3-030-17282-4 (ISBN)978-3-030-17283-1 (ISBN)
Available from: 2019-07-23 Created: 2019-07-23 Last updated: 2019-07-24Bibliographically approved
Zhang, X., Wei, Y., He, W., Qiu, Z. & Zhao, X. (2019). Solar Systems’ Economic and Environmental Performance Assessment. In: Xudong Zhao, Xiaoli Ma (Ed.), Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation: (pp. 453-486). Springer
Open this publication in new window or tab >>Solar Systems’ Economic and Environmental Performance Assessment
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2019 (English)In: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation / [ed] Xudong Zhao, Xiaoli Ma, Springer, 2019, p. 453-486Chapter in book (Refereed)
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.

Place, publisher, year, edition, pages
Springer, 2019
Series
Green Energy and Technology
Keywords
PV, Loop heat pipe, Solar thermal facade, Economic, Environmental
National Category
Energy Engineering
Research subject
Energy and Built Environments
Identifiers
urn:nbn:se:du-30576 (URN)10.1007/978-3-030-17283-1_13 (DOI)2-s2.0-85068769640 (Scopus ID)978-3-030-17282-4 (ISBN)978-3-030-17283-1 (ISBN)
Available from: 2019-07-24 Created: 2019-07-24 Last updated: 2019-07-24Bibliographically approved
Wei, Y., Zhang, X., Shi, Y., Xia, L., Pan, S., Wu, J., . . . Zhao, X. (2018). A review of data-driven approaches for prediction and classification of building energy consumption. Renewable & sustainable energy reviews, 82(1), 1027-1047
Open this publication in new window or tab >>A review of data-driven approaches for prediction and classification of building energy consumption
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2018 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 82, no 1, p. 1027-1047Article in journal (Refereed) Published
Abstract [en]

A recent surge of interest in building energy consumption has generated a tremendous amount of energy data, which boosts the data-driven algorithms for broad application throughout the building industry. This article reviews the prevailing data-driven approaches used in building energy analysis under different archetypes and granularities, including those methods for prediction (artificial neural networks, support vector machines, statistical regression, decision tree and genetic algorithm) and those methods for classification (K-mean clustering, self-organizing map and hierarchy clustering). The review results demonstrate that the data-driven approaches have well addressed a large variety of building energy related applications, such as load forecasting and prediction, energy pattern profiling, regional energy-consumption mapping, benchmarking for building stocks, global retrofit strategies and guideline making etc. Significantly, this review refines a few key tasks for modification of the data-driven approaches in the context of application to building energy analysis. The conclusions drawn in this review could facilitate future micro-scale changes of energy use for a particular building through the appropriate retrofit and the inclusion of renewable energy technologies. It also paves an avenue to explore potential in macro-scale energy-reduction with consideration of customer demands. All these will be useful to establish a better long-term strategy for urban sustainability.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Data driven approach, Building, Energy consumption, Prediction, Classification
National Category
Energy Engineering
Research subject
Energy, Forests and Built Environments
Identifiers
urn:nbn:se:du-26385 (URN)10.1016/j.rser.2017.09.108 (DOI)2-s2.0-85030703701 (Scopus ID)
Available from: 2017-10-09 Created: 2017-10-09 Last updated: 2017-11-15Bibliographically approved
Eriksson, P. E., Swenberg, T., Zhao, X. & Eriksson, Y. (2018). How gaze time on screen impacts the efficacy of visual instructions. Heliyon, 4(6), Article ID e00660.
Open this publication in new window or tab >>How gaze time on screen impacts the efficacy of visual instructions
2018 (English)In: Heliyon, ISSN 2405-8440, Vol. 4, no 6, article id e00660Article in journal (Refereed) Published
Abstract [en]

This article explores whether GTS (gaze time on screen) can be useful as an engagement measure in the screen mediated learning context. Research that exemplifies ways of measuring engagement in the on-line education context usually does not address engagement metrics and engagement evaluation methods that are unique to the diverse contemporary instructional media landscape. Nevertheless, unambiguous construct definitions of engagement and standardized engagement evaluation methods are needed to leverage instructional media's efficacy. By analyzing the results from a mixed methods eye-tracking study of fifty-seven participants evaluating their visual and assembly performance levels in relation to three visual, procedural instructions that are versions of the same procedural instruction, we found that the mean GTS-values in each group were rather similar. However, the original GTS-values outputted from the ET-computer were not entirely correct and needed to be manually checked and cross validated. Thus, GTS appears not to be a reliable, universally applicable automatic engagement measure in screen-based instructional efforts. Still, we could establish that the overall performance of learners was somewhat negatively impacted by lower than mean GTS-scores, when checking the performance levels of the entire group (N = 57). When checking the stimuli groups individually (N = 17, 20, 20), the structural diagram group's assembly time durations were positively influenced by higher than mean GTS-scores.

Keywords
psychology, education, information science
National Category
Design Learning Arts Educational Sciences
Research subject
Intercultural Studies
Identifiers
urn:nbn:se:du-28050 (URN)10.1016/j.heliyon.2018.e00660 (DOI)30003156 (PubMedID)2-s2.0-85048981564 (Scopus ID)
Note

Open Access APC beslut 5/2018

Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-11-23Bibliographically approved
Nordström, C., Farsari, I., Zhao, X. & Ramsay, S. (2018). Working with Swedes. Mondå Förlag
Open this publication in new window or tab >>Working with Swedes
2018 (English)Book (Other academic)
Place, publisher, year, edition, pages
Mondå Förlag, 2018
Keywords
Arbetsliv, Kultur, Socialantropologi, Svenskar, Sverige
National Category
Sociology Ethnology Human Geography
Research subject
Complex Systems – Microdata Analysis
Identifiers
urn:nbn:se:du-30015 (URN)9788293622093 (ISBN)
Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-05-10Bibliographically approved
Zhao, X., Carling, K. & Håkansson, J. (2017). An evaluation of the reliability of GPS-based transportation data. In: Proceedings of IAC in Vienna 2017: . Paper presented at IAC (International Academic Conference on Transport, Logistics, Tourism and Sport Science) in Vienna November 24-25 2017 (pp. 323-334). , Article ID IAC201711035.
Open this publication in new window or tab >>An evaluation of the reliability of GPS-based transportation data
2017 (English)In: Proceedings of IAC in Vienna 2017, 2017, p. 323-334, article id IAC201711035Conference paper, Published paper (Refereed)
Abstract [en]

GPS-based data are becoming a cornerstone for real-time transportation applications. Tracking data of vehicles from GPS receivers are however susceptible to measurement errors. The assessment of the reliability of data from GPS receiver is a neglected issue, especially in a real road network setting and in the phase after data transfer but before information identification. An evaluation method is outlined and carried out by conducting a randomized experiment. We assess the reliability of GPS-based transportation data on geographical position, speed, and elevation from three varied receivers GlobalSat BT-338X, Magellan SporTrak Pro and smart phone for three transportation modes: bicycle, car, and bus. The positional error ranging from 0158 meters, and 74% to 100% with an error within 5 meters depending on the transportation mode and route, there is also a non-negligible risk for aberrant positioning. Speed is slightly underestimated or overestimated with errors around 5km/h except for SporTrak Pro which had an error of -10 km/h. Elevation measurements are unreliable with errors bigger than 100 meters.

Keywords
Transportation, GPS tracking, Reliability, Road network
National Category
Transport Systems and Logistics Geosciences, Multidisciplinary
Research subject
Complex Systems – Microdata Analysis
Identifiers
urn:nbn:se:du-26981 (URN)978-80-88203-04-9 (ISBN)
Conference
IAC (International Academic Conference on Transport, Logistics, Tourism and Sport Science) in Vienna November 24-25 2017
Available from: 2018-01-26 Created: 2018-01-26 Last updated: 2018-01-26Bibliographically approved
Zhao, X. (2017). Government vs Market in Sustainable Residential Development?: Microdata analysis of car travel, CO2 emission and residence location. (Doctoral dissertation). Borlänge: Dalarna University
Open this publication in new window or tab >>Government vs Market in Sustainable Residential Development?: Microdata analysis of car travel, CO2 emission and residence location
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Increasing car usage and travel demands between residential locations and destinations in order to fulfill the various needs of residents is a primary cause of CO2 emissions. To win the battle against climate change, a better understanding of the question relating to which urban residential form may most effectively mitigate the CO2 emissions is the key pathway.

This dissertation is concerned with the above problem and it mainly considers three objectives in providing insights on answering the question. The first objective is to comprehensively and microscopically understand intra-urban car travel behavior. The second objective is to estimate the induced CO2 emissions from daily intra-urban car travel and to ex-ante evaluate residential plans. The third objective is to assess whether the governmental sustainable residential development objective is aligned with the objectives of the estate market actors. To explore the research questions related to the objectives, a microdata analysis process (data collection, data assessment and transformation, data storage, data analysis and decision-making) is applied and is found essential in gaining access to key variables in exploring the answer of a preferable urban form. The dissertation offers many new solutions to various technical aspects through a microdata analysis process.

The primary contribution of this dissertation is that it outlines an operational model that comprehensively integrates the investors’ investment strategy, the residents’ choice behavior, and the governmental sustainability objective in the interest of making an ex-ante assessment of residential plans. This ex-ante assessment provides decision-support in sustainable residential development at foremost local level.

The first finding from the implementation of the model on the case study is that the market actors’ objectives are, in general, aligned with the government’s sustainable residential development objective. The second finding indicates that re-shaping the urban form into a compact city is preferable in mitigating CO2 emissions, in spite of the fact that the case city is of a polycentric urban form. These findings provide support for those advocating the compact city as the ideal for sustainable residential development, and also provide foresight on settling the answer to the preferred re-shaping of urban forms in climate change.

Place, publisher, year, edition, pages
Borlänge: Dalarna University, 2017. p. 140
Series
Dalarna Doctoral Dissertations in Microdata Analysis ; 6
National Category
Other Social Sciences not elsewhere specified
Research subject
Complex Systems – Microdata Analysis, General Microdata Analysis - transports
Identifiers
urn:nbn:se:du-24685 (URN)978-91-85941-84-1 (ISBN)
Public defence
2017-04-28, Clas Ohlson, Studenternas Hus Tenoren, Röda vägen, Borlänge, 13:00 (English)
Opponent
Supervisors
Available from: 2017-04-05 Created: 2017-04-04 Last updated: 2019-06-17Bibliographically approved
Zhao, X., Carling, K. & Håkansson, J. (2017). On assessing governmental sustainable residential planning and its alignment with residents’ and estate investors’ objectives. Borlänge: Högskolan Dalarna
Open this publication in new window or tab >>On assessing governmental sustainable residential planning and its alignment with residents’ and estate investors’ objectives
2017 (English)Report (Other academic)
Abstract [en]

There are three key actors in forming the sustainable spatial distribution of residency in an area, (local) government, the estate investor and the resident, each with its own objective. Most urban planning studies have mainly focused on the ex-post evaluation of residential development by considering the objective of each actor separately. This paper outlines a conceptual model where the three key actors and their unique objectives are integrated with the aim of providing an ex-ante evaluation of residential development for government to make policies operational on a micro level. The methodology is implemented on a Swedish city, where sustainable residential development is in high need due to the influx of immigrants. The case study demonstrates that the model can integrate the macro and micro actors well. The model can provide noteworthy insights for the government on where the objectives of sustainability, livability and profit can be met. A sensitivity check of the parameter settings shows that the implementation of the model is robust for replication in other cities.

Place, publisher, year, edition, pages
Borlänge: Högskolan Dalarna, 2017. p. 20
Series
Working papers in transport, tourism, information technology and microdata analysis, ISSN 1650-5581 ; 2017:01
Keywords
Sustainable urban development; CO2 emissions; Multi-agent system model; Urban mobility
National Category
Social and Economic Geography
Research subject
Complex Systems – Microdata Analysis
Identifiers
urn:nbn:se:du-24514 (URN)
Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2017-11-15Bibliographically approved
Zhao, X., Carling, K. & Håkansson, J. (2017). Residential planning, driver mobility and CO2 emission: a microscopic look at Borlänge in Sweden. European Planning Studies, 25(9), 1597-1614
Open this publication in new window or tab >>Residential planning, driver mobility and CO2 emission: a microscopic look at Borlänge in Sweden
2017 (English)In: European Planning Studies, ISSN 0965-4313, E-ISSN 1469-5944, Vol. 25, no 9, p. 1597-1614Article in journal (Refereed) Published
Abstract [en]

In a city there are hotspots that attract citizens, and most of the transportation arises when citizens move between their residence and primary destinations (i.e. hotspots). However, an ex ante evaluation of energy-efficient mobility and urban residential planning has seldom been conducted. Therefore, this paper proposes an ex ante evaluation method to quantify the impacts, in terms of CO2 emissions induced by intra-urban car mobility, of residential plans for various urban areas. The method is illustrated in a case study of a Swedish midsize city, which is presently preoccupied with urban planning of new residential areas in response to substantial population growth due to immigration. In general, CO2 emissions increase from the continued urban core area (CUCA), to the sub-polycentric area (SPA), to the edge urbanization area (EUA), where CO2 emission of EUA is twice that of the CUCA. The average travel distances also increase in the same pattern, though the relative increase is more than four times. Apartment buildings could be more effective in meeting residential needs and mitigating CO2 emissions than dispersed single-family houses. 

Keywords
Ex ante evaluation, GPS-tracking data, spatial distribution, urban form
National Category
Social and Economic Geography
Research subject
Complex Systems – Microdata Analysis
Identifiers
urn:nbn:se:du-24824 (URN)10.1080/09654313.2017.1317722 (DOI)000404932100007 ()2-s2.0-85017904082 (Scopus ID)
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2017-11-15Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7512-5321

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