Welcome to Journal of Thermal Science!

CONTENTS-Volume 28, Issue 6, November-December 2019

Nov. 5, 2019


Springer Link: https://link.springer.com/journal/11630/28/6


1. Special Issue for Building Energy Conservation and Renewable Energy Integration

Journal of Thermal Science, 2019, 28(6): 1103.


With the development of society and the improvement of people’s living standards, the thermal comfort requirement of indoor environment is increasing, which leads to more and more energy consumption. It is essential to scientifically develop, strategically promote and practically implement building energy saving techniques.

Generally speaking, there are four basic approaches for building energy saving, namely, optimizing building design (e.g. Improving the insulation of the enclosure, optimizing building form); applying building equipment with high energy efficiency (e.g. high energy efficiency air conditioner, energy saving lamps); advanced building energy supply system (e.g. distributed energy system, the application of renewable energy); and optimizing equipment operation and control.

With the support from authors and reviewers, 13 original research papers and one review paper have been accepted in this special issue. In this special issue, the 13 papers cover the first three pathway described above, besides, there are several studies on energy saving evaluation tools or models, e.g. “A quantitative process-based inventory study on material embodied carbon emissions of residential, office, and commercial buildings in China”, “Development and application of evaluation index system and model for existing building green-retrofitting”.

The topics of the Special Issue on the Building Energy Conservation and Renewable Energy Integration are related to a wider coverage of innovative research and studies on the building energy saving techniques. We believe the current Special Issue of Journal of Thermal Science will be of interest and relevance to a broad scope of the scientific community. Moreover, we hope this Special Issue can attract more attention to the topic of building energy conservation and renewable energy integration.

Finally, it is a pleasure that we were given the opportunity to edit this Special Issue. We would like to thank all the contributors of this Special Issue for their support and cooperation. We also thank all the reviewers for their critical comments to ensure the academic quality of this Special Issue.


Guest Editors

Associate Prof. LIU Zhijian

North China Electric Power University, Baoding, China

E-Mail: zhijianliu@ncepu.edu.cn

Prof. LI Hongqiang

Hunan University, Changsha, China

E-Mail: lhq@hnu.edu.cn

Dr. LI Guiqiang

University of Hull, Hull, UK

E-Mail: Guiqiang.Li@hull.ac.uk

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1234-1


2. Scientometric of Nearly Zero Energy Building Research: A Systematic Review from the Perspective of Co-Citation Analysis

WANG Mengmeng, LIU Xiaojun, FU Hanliang, CHEN Baiyu

Corresponding author: WANG Mengmeng, E-mail: wangmengmeng@live.xauat.edu.cn

Journal of Thermal Science, 2019, 28(6): 1104-1114.


Keywords: nearly zero energy building (nZEB), scientometric, co-citation, CiteSpace

Abstract: As an important building type to diminish energy use and greenhouse gas emissions in the construction industry, nearly zero energy building (nZEB) has attracted much attention from many scholars, with volumes of research findings published. However, quantitative and systematic reviews on those findings are rarely conducted by researchers. Therefore, a visualized presentation regarding the advancement of nZEB research was made in this study by applying the scientometric method of co-citation analysis to 704 publications retrieved from the Web of Science database from 2006 to 2018. Here, the key conclusions drawn after the research are as follows: (1) Italy, the USA and Spain are the top three nations by the number of nZEB publications; (2) Energy and Buildings, Applied Energy and Energy are the journals with the highest number of published nZEB articles; (3) Politecnico di Milano, Aalto University and Politecnico di Torino are the most influential core organizations in the field of nZEB; (4) Professor Kurnitski J, Professor Corgnati SP and Professor D'Agostino D are the leading nZEB experts; (5) “cost optimal”, “life cycle assessment”, “technical system”, “design” and “indoor environment quality” are the major research directions in the field of nZEB; (6) A multi-stage optimization method for cost-optimal and nearly zero-energy building solutions in line with the EPBD 2010, co-authored by Hamdy M, is the most cited nZEB reference; (7) “residential building”, “building energy saving technology”, “simulation method” and “thermal comfort”, etc. are the hot topics in nZEB research at present and in the future. This research is designed to provide valuable information for scholars interested in the field of nZEB.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1172-y


3.  Optimizing Building Envelope Dimensions for Passive Solar Houses in the Qinghai-Tibetan Region: Window to Wall Ratio and Depth of Sunspace

LIU Zhijian, WU Di, LI Junyang, YU Hancheng, HE Baojie

Corresponding author: LIU Zhijian, E-mail: zhijianliu@ncepu.edu.cn

Journal of Thermal Science, 2019, 28(6): 1115-1128.


Keywords: passive solar house, indoor thermal comfort, sunspace depth, WWR (window to wall ratio), PPD (Predicted Percent Dissatisfied)

Abstract: It has been a focus to reduce the energy consumption and improve the space heating performance of high-altitude buildings in winter seasons. In view of the abundant solar energy resources of the high-altitude region, the establishment of passive solar houses should be an effective strategy to deal with the problem of thermal comfort. Both window to wall ratio (WWR) and sunspace depth are of vital importance to determine the thermal comfort level of passive solar houses, while there are limited studies on analyzing their impacts on passive solar houses in high-altitude regions. Therefore, this study is designed to examine how WWR and sunspace depth affect space heating of passive solar houses in the Qinghai-Tibetan region. To be specific, the hourly radiation temperature variations and percentages of dissatisfaction of the residential building with different sunspace depth/WWR (including 0.9m/33%, 0.9m/45%, 0.9m/60%, 1.2m/33% and 1.5m/33%) were quantitatively examined. Results indicated that under the condition of 0.9m/45%, the overall average radiation temperature of the building was approximately 16°C during the entire heating season, which could better satisfy the heating requirements. Meanwhile, the average temperature was higher, and the thermal comfort level was better under the ratio of 45% or the depth of 1.5 m, when only an individual factor in either ratio or depth was considered. These findings can provide references for the determination of dimensions of passive solar houses in high-altitude regions.

Springer Link: https://link.springer.com/article/10.1007/s11630-018-1047-7


4. Assessment of Building External Wall Thermal Performance Based on Temperature Deviation Impact Factor under Discontinuous Radiant Heating

YANG Jie, WANG Jun, XIONG Feng, LIANG Hao, LI Yunzhang

Corresponding author: WANG Jun, E-mail: wangjunhvac@163.com

Journal of Thermal Science, 2019, 28(6): 1129-1140.


Keywords: temperature deviation impact factor, building external wall, thermal performance, discontinuous radiant heating

Abstract: As the variation and timely meeting thermal environment requirement of indoor air temperature has a close relationship with the thermal performance of building external wall under discontinuous radiant heating condition, one appropriate assessment method or index for assessing the building external wall thermal performance is very necessary. In order to reasonably evaluate the thermal performance of external wall under discontinuous radiant heating condition and build the direct connections and interactions among the indoor air temperature, external wall inner surface temperature and outdoor air temperature, the first and second impact factors of temperature deviation were established, based on one mathematical model of room heat transfer. For one experimental room and four types of external walls under discontinuous radiant heating condition, both the influence of the external wall inner surface temperature deviation on the indoor air temperature and that of the outdoor air temperature deviation on the external wall inner surface temperature were determined effectively with the first and second impact factors of temperature deviation. In addition, favourable performance for the self-insulation and inner insulation walls were found, due to their superiority in effectively and timely improving the indoor thermal environment under discontinuous radiant heating condition.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1173-x


5. A Comprehensive Evaluation on Energy, Economic and Environmental Performance of the Trombe Wall during the Heating Season

ZHANG Hongliang, SHU Haiwen

Corresponding author: SHU Haiwen, E-mail: shuhaiwen@dlut.edu.cn

Journal of Thermal Science, 2019, 28(6): 1141-1149.


Keywords: Trombe wall, energy evaluation, economic evaluation, environmental evaluation, heating load

Abstract: Trombe wall is a passive building energy saving technology that uses solar energy to reduce buildings’ heating load and adjust indoor thermal environment. In recent years, much research has been done to increase the thermal efficiency of Trombe wall, but little is focused on the evaluation of Trombe wall from energy, economic and environmental aspects comprehensively. Based on the thermal performance calculation method in ISO 52016-2:2017(E), the authors proposed a concise method to evaluate the energy, economic and environmental performance of ventilated and non-ventilated Trombe walls during a heating season. Firstly, non-iteration calculation methods were introduced for the energy evaluation of Trombe wall and conventional wall during the heating season. Then the economic and environmental evaluation models were brought out according to the energy performance of Trombe wall. After that, a residential building was presented as the case building to evaluate Trombe walls’ performance in five building climate zones of China. The calculation results showed that both heating degree days and solar radiation had significant impact on the energy saving effect of Trombe walls. In comparison with non-ventilated Trombe walls, ventilated ones displayed more obvious energy saving potential in all five climate regions, which can provide averagely 62% more heating for the room in the case study. Though the heating degree days of Guangzhou (hot-summer and warm-winter zone) was the smallest in the five zones, ventilated Trombe wall in the zone had the poorest economic performance due to the scarcest solar radiation during the heating season.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1176-7


6. Research on Landscape Energy-Saving Integrated Water Curtain System

GUO Pengxin, LI Hongqiang, HE Changjie, ZHENG Yingfa, LI Shuisheng, ZHANG Guoqiang

Corresponding author: Li Hongqiang, E-mail: lhq@hnu.edu.cn

Journal of Thermal Science, 2019, 28(6): 1150-1163.


Keywords: glass curtain wall, integration of landscape and energy-saving, water curtain sunshade, evaporative cooling, natural resources

Abstract: Aiming at the serious heat and cold loss of the building glass curtain wall in the field of amusement and tourism, and the need to meet the landscape requirements of the building facade, this paper put forward the idea of integrating the shading and consumption reduction of glass curtain wall with the landscape requirements, that is, the water curtain was set outside the glass curtain wall to form a landscape energy-saving integrated water curtain wall system, while meeting the needs of landscape and shading. By establishing the numerical calculation model of the system, the corresponding relationship between the thickness of water film and the weakening of solar radiation intensity was revealed, as well as the influence of wind speed and wind direction on the nozzle exit angle and velocity selection; and the synergistic law of air flow rate and air temperature drop amplitude. The results showed that the water film thickness at 3‒4 cm can reduce the solar radiation by 65%‒80%. The temperature of the air layer between the water film and the curtain wall decreased as the air flow rate decreased, when the thickness of water film was 2 cm and the air velocity was 0.5‒1.5 m/s, the air temperature dropped to 2.47‒3.6°C. Finally, through the analysis of the actual project—ICE World & WATER Park, the system can reduce 66.8% of solar radiation, and reduce the air layer temperature by 3.9°C.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1239-9


7. Path Analysis of Energy-Saving Technology in Yangtze River Basin Based on Multi-Objective and Multi-Parameter Optimisation

MENG Xiangzhong, YU Wei, ZHENG Chuyu, WANG Di, CAO Xinyun

Corresponding author: YU Wei, E-mail: yuweixscq@126.com

Journal of Thermal Science, 2019, 28(6): 1164-1175.


Keywords: Yangtze River Basin, energy consumption, multi-objective and multi-parameter optimisation passive design, energy-saving technology path

Abstract: The Yangtze River Basin in China is characterised by hot- and cold-humid climates in summer and winter, respectively. Thus, increased demand for heating and cooling energy according to the season, as well as poor indoor thermal comfort, are inevitable. To overcome this problem, this study focused on the influence of passive design and heating, ventilation, and air conditioning equipment performance on the energy performance of residential buildings, and explored potential energy-saving technology paths involving passive design and improved coefficient of performance through a multi-objective and multi-parameter optimisation technique. A large-scale questionnaire survey covering a typical city was first conducted to identify family lifestyle patterns regarding time spent at home, family type, air conditioner use habits, indoor thermal comfort, etc. Then, the actual heating and cooling energy consumption and information of model building were determined for this region. Subsequently, the design parameters of an individual building were simulated using Energyplus to investigate the cooling and heating energy consumption for a typical residential building with an air conditioner. The results indicated an improvement of approximately 30% in energy efficiency through optimisation of the external-wall insulation thickness and the external-window and shading performance, and through use of appropriate ventilation technology. Thus, a multi-objective and multi-parameter optimisation model was developed to achieve comprehensive optimisation of several design parameters. Experimental results showed that comprehensive optimisation could not only reduce cooling and heating energy consumption, but also improve the thermal comfort level achieved with a non-artificial cooling and heating source. Finally, three energy-saving technology paths were formulated to achieve a balance between indoor thermal comfort improvement and the target energy efficiency (20 kWh/(m2a)). The findings of this study have implications for the future design of buildings in the Yangtze River Basin, and for modification of existing buildings for improved energy efficiency.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1102-z


8. Thermal Analysis of a Volumetric Solar Receiver

CHEN Longfei, YANG Ming, LI Jinping, BAI Yakai, LI Xiaoxia, TANG Wenxue, YANG Nancong, WANG Zhifeng

Corresponding author: WANG Zhifeng, E-mail: zhifeng@vip.sina.com

Journal of Thermal Science, 2019, 28(6): 1176-1185.


Keywords: solar receiver, solid-liquid composite absorber, silicon carbide porous ceramic, volumetric solar collector

Abstract: The volumetric receiver has received wide attention due to its high thermal efficiency. This paper studied a new type of a solid-liquid composite volumetric receiver. The heat transfer in a solid-liquid composite volumetric solar receiver was analyzed using a one-dimensional unsteady simulation model of the solid-liquid receiver. The model included absorption of the incident solar radiation by the glass window, the silicon carbide porous ceramic heat absorber panel and the water. The results were verified against experimental data for a volumetric receiver and the error did not exceed 10%. It can be used to predict the heat transfer in solid-liquid composite volumetric receivers.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1220-7


9. Research on Photovoltaic Performance Reduction due to Dust Deposition: Modelling and Experimental Approach

CHEN Yingya, WANG Dengjia, LIU Yanfeng, DONG Yu, LIU Jiaping

Corresponding author: WANG Dengjia, E-mail: wangdengjia@xauat.edu.cn

Journal of Thermal Science, 2019, 28(6): 1186-1194.


Keywords: photovoltaic technology, dust deposition, conversion efficiency, fill factor

Abstract: Photovoltaic (PV) power generation technology is the main renewable energy utilization technology. However, dust deposition severely affects the PV power generation efficiency and decreases the production capacity of PV power plants. In this study, the factors affecting PV technology were divided into the following three types: occlusion, corrosion, and temperature rise. A dust-collecting PV model considering dust deposition and rainfall scouring was established; a PV performance index was proposed. By conducting experiments with different dust mass densities, it was found that the short-circuit current (SCC), open-circuit voltage (OCV), and PV output power of PV decreased with the increase in dust mass density. In the initial stage of dust deposition, dust exhibited the greatest effect on the performance of PV. In the later stage of dust deposition, the effect of dust deposition became stable. The initial 10 g/m2 dust decreased the PV output power by 34%. In addition, the conversion efficiency and fill factor (FF) decreased with the increase in dust mass density; both of them were exponential functions. When the dust mass density was low (less than 30 g/m2), the dust mass density increased by 10 g/m2, and the conversion efficiency decreased by an average of 3.4%. Finally, by conducting economic calculations, it was found that a PV power plant where dust has not removed for one year will cause 12% loss of power generation.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1177-6


10. Cold Storage Capacity for Solar Air-Conditioning in Office Buildings in Different Climates

SUN Zhifeng, ZHAO Yaohua, XU Wei, WANG Dongxu, LI Huiyong, ZHANG Xinyu, LI Huai, LI Yang

Journal of Thermal Science, 2019, 28(6): 1195-1204.


Keywords: office building, solar air-conditioning system, cold storage capacity, TRNSYS

Abstract: The building sector accounts for more than 40% of the global energy consumption. This consumption may be lowered by reducing building energy requirements and using renewable energy in building energy supply systems. Solar air-conditioning systems (SACS) are a promising solution for the reduction of conventional energy in buildings. The storage, especially the cold storage, plays an important role in SACS for unstable solar irradiation. In this paper, we took the absorption refrigerating unit as an example, and the solar air-conditioning system of an office building in Beijing was simulated. The accuracy of this model was verified by comparing with the SACS operation data. Moreover, based on the simulation data, the cold storage capacity of the solar air-conditioning system in different climatic regions was studied. The cold storage capacities of SACS in 20 cities distributed in different climate regions were studied systematically. The results simulated by our proposed model will be beneficial to the SACS design, and will enlarge the application of SACS.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1067-y


11. Experimental and Comparison Study on Two Solar Dish Systems with a High Concentration Ratio

CHEN Haifei, LI Guiqiang, YANG Jie, ZHANG Fuwei, LIANG Ming, JI Jie

Corresponding authors: LI Guiqiang, E-mails: guiqiang.li@hull.ac.uk

JI Jie, jijie@ustc.edu.cn

Journal of Thermal Science, 2019, 28(6): 1205-1211.


Keywords: high concentration ratio, thermal science, dish system, solar energy

Abstract: Two high concentrating solar systems have been established with dish concentrator and plane-mirrors array concentrator. In the paper, the thermal performance has been experimentally studied with jet water cooling device and flat microchannel water-cooled device. The experimental results show that the maximum surface temperature difference of the dish concentrating system is greater than 20°C, while the plane-mirrors array system is lower than 4°C. It indicates that the plane-mirrors array concentrator has better uniformity. As the concentration ratio increases, the electrical efficiency of the concentrating photovoltaic system gradually decreases. When the concentration ratio is 200, the electrical efficiency of the photovoltaic system is 25%. The concentration ratio of 500 times or less is considered to be a suitable value, and then the electrical efficiency can still exceed 20%. It is found that the plane-mirrors array solar system is more suitable for the photovoltaic system than dish type system, which is only suitable for thermal power generation system.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1104-x


12. Discussion on Performance Evaluation Method of Distributed Combined Cooling, Heating, and Power System

SHAO Youyuan, CHEN Baiman, XIAO Hanmin, QIN Frank G.F.

Corresponding author: SHAO Youyuan, E-mail: shaoyy@dgut.edu.cn

QIN Frank G.F., qingf@dgut.edu.cn

Journal of Thermal Science, 2019, 28(6): 1212-1220.


Keywords: distributed energy systems (DES), energy efficiency, performance index, exergy analysis

Abstract: This paper briefly analyzed some problems and limitations of existing evaluation indicators for distributed energy system performance. Based on the diversity and difference of the energy form and grade of cooling, heating and power in the distributed combined cooling, heating, and power (CCHP) system, this paper proposed three-index evaluation system composed of key indicators including relative energy saving rate, exergy efficiency and thermoelectric ratio. In order to further prove the reasonableness and scientificity of the evaluation index system applied in performance evaluation of distributed CCHP system, it enumerated, calculated, and evaluated the energy conservation of three engineering cases. The evaluation results showed that the high energy-saving rate of the system did not mean good energy-saving, but also the efficiency of the system should be examined. Only when the energy saving rate and exergy efficiency were both high, can the energy saving performance of the system be demonstrated. When the energy-saving rate was high and the efficiency was not high, it is shown that the energy-saving of the system had great room for improvement.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1219-0


13.Multi-Objective Particle Swarm Optimization (MOPSO) for a Distributed Energy System Integrated with Energy Storage

ZHANG Jian, CHO Heejin, MAGO Pedro J., ZHANG Hongguang, YANG Fubin

Corresponding author: CHO Heejin, E-mail: cho@me.msstate.edu

Journal of Thermal Science, 2019, 28(6): 1221-1235.


Keywords: multi-objective particle swarm optimization, distributed energy system, payback period, carbon dioxide emission

Abstract: Distributed energy systems are considered as a promising technology for sustainable development and have become a popular research topic in the areas of building energy systems. This work presents a case study of optimizing an integrated distributed energy system consisting of combined heat and power (CHP), photovoltaics (PV), and electric and/or thermal energy storage for a hospital and large hotel buildings located in Texas and California. First, simulation models for all subsystems, which are developed individually, are integrated together according to a control strategy designed to satisfy both the electric and thermal energy requirements of a building. Subsequently, a multi-objective particle swarm optimization (MOPSO) is employed to obtain an optimal design of each subsystem. The objectives of the optimization are to minimize the simple payback period (PBP) and maximize the reduction of carbon dioxide emissions (RCDE). Finally, the energy performance for the selected building types and locations are analyzed after the optimization. Results indicate that the proposed optimization method could be applied to determine an optimal design of distributed energy systems, which reaches a trade-off between the economic and environmental performance for different buildings. With the presented distributed energy system, a peak shaving in electricity of about 300 kW and a reduction in boiler fuel consumption of 610 kW could be attained for the hospital building located in California for a winter day. For the summer and transition seasons, electricity peak shaving of 800 kW and 600 kW could be achieved, respectively.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1133-5


14. A Quantitative Process-Based Inventory Study on Material Embodied Carbon Emissions of Residential, Office, and Commercial Buildings in China

LUO Zhixing, CANG Yujie, ZHANG Nan, YANG Liu, LIU Jiaping

Corresponding author: YANG Liu, E-mail: yangliu@xauat.edu.cn

Journal of Thermal Science, 2019, 28(6): 1236-1251.


Keywords: embodied carbon emissions, life cycle analysis, materialization phase, building material

Abstract: Studies on building carbon emissions focus mainly on the materialization phase of life cycle, as carbon emissions in this stage is intensive and high. This paper proposes a simplified model to calculate embodied carbon emissions in building design stage by conducting a process-based inventory analysis of carbon emissions from materials used in 129 residential buildings, 41 office buildings, and 21 commercial buildings during materialization phase. The results indicate that average carbon emissions per unit area from building materials used in residential buildings, office buildings, and commercial buildings are 514.66 kgCO2e/m2, 533.69 kgCO2e/m2 and 494.19 kgCO2e/m2, respectively. Besides, ten kinds of building materials (namely, steel, commercial concrete, wall building materials, mortar, copper core cables, architectural ceramics, PVC pipes, thermal insulation materials, doors and windows, and water paint) constitute 99% of total carbon emissions in all three types of buildings. These materials are major carbon emissions sources in materialization phase. Thus, embodied carbon emissions can be significantly reduced by limiting the amount of these materials in architectural design as well as by using environmental friendly materials.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1165-x


15. Development and Application of Evaluation Index System and Model for Existing Building Green-Retrofitting

MENG Chong, WANG Qingqin, LI Baizhan, GUO Chunmei, ZHAO Naini

Corresponding author: WANG Qingqin, E-mail: cabr_jks@126.com

Journal of Thermal Science, 2019, 28(6): 1252-1261.


Keywords: existing building, green-retrofitting, evaluation system, analytic hierarchy process, fuzzy evaluation model

Abstract: This paper establishes an evaluation index system for existing building green-retrofitting considering different building majors. The weights of indicators at different levels were determined by using decision-making analytic hierarchy process. According to fuzzy mathematics theory, indicators at different levels were taken into an evaluation factor set while three-star level, two-star level, one-star level and unqualified level were taken as the comment set to develop a fuzzy comprehensive evaluation model for the green retrofitting of existing buildings. Additionally, the evaluation system proposed by this paper and the national standard “Assessment standard for green building” GB/T 50378-2014 were used in the assessment of a certain office after green retrofitting as a case study. The case study indicates that the evaluation developed by this research are more applicable for green retrofitting of existing building, while the national standard “Assessment standard for green building” has limitations except for new building.

Springer Link: https://link.springer.com/article/10.1007/s11630-019-1122-8