Article
Thermodynamics
Dardan Klimenta, Dusko Minic, Lana Pantic-Randelovic, Ivana Radonjic-Mitic, Milena Premovic-Zecevic
Summary: The goal of this study is to model steady-state heat transfer of five different photovoltaic laminates using the finite element method. The model is applicable to all existing photovoltaic technologies and includes a new iterative procedure for calculating the maximum operating cell temperature. The thermal model is validated and calibrated using existing data from six independent experiments.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Tingting Zhu, Torben Ommen, Wiebke Meesenburg, Jan Eric Thorsen, Brian Elmegaard
Summary: The study investigated the steady state thermal behavior of a booster heat pump (BHP) under different forward temperatures and flow rates, revealing that the BHP reached maximum COP of 4.95, heating capacity of 15.36 kW, and exergy efficiency of 33.4% at a forward temperature of 45 degrees Celsius. The compressor was found to have the highest exergy destruction among the components.
Article
Thermodynamics
Martina Capone, Elisa Guelpa, Vittorio Verda
Summary: This paper studies the impact of heat capacities on the thermal response of systems, presenting and comparing four different models. It concludes that the equivalent one-equation model is capable of producing accurate solutions in significantly reduced computational time. When applied to the Turin district heating network, this simplified model shows great potential for efficient and accurate results.
Article
Thermodynamics
Hong Yu, Hengyun Zhang, Jinghe Shi, Shunbo Liu, Zhaozang Yi, Shen Xu, Xinwei Wang
Summary: In this work, a new method of quasi-steady state heat guarding measurement is proposed to determine the thermophysical parameters of cylindrical batteries. By using finite element analysis and measurement of a standard ANSI 304 stainless steel sample, the effectiveness of the heat guarding method is evaluated. The experimental results show that this method can accurately determine the axial thermal conductivity and specific heat of cylindrical batteries, which are crucial for thermal design and management of these batteries.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Lin Fu, Yonghong Li, Yanting Wu, Xiaoyin Wang, Yi Jiang
Summary: The study introduces a low carbon district heating system that is suitable for large cities in Northern China, aiming to reduce energy consumption, emissions, and improve the economics of the heating systems.
Article
Energy & Fuels
Arjun Sivaprasad, Prasenjit Basu
Summary: This paper presents the development of a new soil thermal conductivity measurement device that can simulate soil under different stress conditions and estimate both transient and steady-state thermal conductivity. The results from tests on seven different soils show that the transient-state thermal conductivity increases beyond a certain threshold value of temperature increment rate.
Article
Thermodynamics
Biaojie Yan, Bingqing Li, Xin Wang, Tao Fa, Pengcheng Zhang
Summary: A new model combining a neural network with the finite element method was constructed to measure the thermal conductivity of materials at room temperature. The accuracy of the model was validated using experimental data and it is suitable for most ceramics and ceramic-based composites.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Zhihua Ge, Wanggang Fang, Shunjiang Wang, Junhong Hao, Yunxi Yang, Liang Tian, Jian Sun, Fang Dong
Summary: The intelligent heating system improves heating efficiency and promotes renewable energy utilization for the realization of the dual-carbon strategy. This paper presents a dynamic model based on standardized thermal resistance to simulate key components and construct an overall dynamic heat current model. The model comprehensively reflects the heat transfer, storage, and delay characteristics of the heat exchanger, piping, and building. An iterative method is proposed to develop heating strategies for quality regulation. The user-following strategy has the highest energy-saving potential of 25.27% compared to the all-day strategy. Additionally, five different heating strategies are proposed for energy-saving operation, with the trapezoid type achieving the highest energy-saving ratio of 9.41%.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Zichan Xie, Haichao Wang, Pengmin Hua, Risto Lahdelma
Summary: This study introduces a novel and efficient method for dynamic thermal modelling of district heating pipes. The method uses discrete event simulation to track water frontiers and reduces computational complexity. The proposed model accurately computes outlet water temperature, temperature profile along the pipe, and heat loss. The model was validated against real measurements and showed accurate predictions.
Article
Thermodynamics
Ieva Pakere, Maksims Feofilovs, Kertu Lepiksaar, Valdis Vitolins, Dagnija Blumberga
Summary: Implementing innovation and sustainable development of district heating requires sound energy planning at the national and local levels. Research shows that phasing out natural gas and integrating heat pumps can increase energy efficiency and reduce heating costs, with the help of waste heat utilization and increased thermal storage capacity.
Article
Nanoscience & Nanotechnology
Zhe Cheng, Fengwen Mu, Xiaoyang Ji, Tiangui You, Wenhui Xu, Tadatomo Suga, Xin Ou, David G. Cahill, Samuel Graham
Summary: This work introduces a thermal mapping technique for buried semiconductor interfaces and identifies weakly bonded interfaces caused by high-temperature annealing. It also highlights the capability of using steady-state temperature rise induced by TDTR laser to probe thermal boundary conductance variations of buried interfaces.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Polymer Science
Jorge-Enrique Rivera-Salinas, Karla-Monzerratt Gregorio-Jauregui, Heidi-Andrea Fonseca-Florido, Carlos-Alberto avila-Orta, Eduardo Ramirez-Vargas, Jose-Antonio Romero-Serrano, Alejandro Cruz-Ramirez, Victor-Hugo Gutierrez-Perez, Seydy-Lizbeth Olvera-Vazquez, Lucero Rosales-Marines
Summary: The thermal performance of closed-cell foams relies on thermal conductivity, with convective contribution often ignored in favor of conductive contribution for analysis. The criteria for disregarding convective heat flux based on cell diameter is inconsistent across literature, while natural convection in porous materials proves worthy of research. Heat transported by convection accounts for about 20% of heat conducted within foam at Ra=10(3), influencing average conductivity by about 4.5%.
Article
Thermodynamics
Mengke Jing, Shujie Zhang, Lisong Fu, Guoquan Cao, Rui Wang
Summary: A new strategy using cured-in-place pipe (CIPP) liners was proposed for the maintenance of district heating (DH) pipes, which can solve the problem of increased heat loss due to aging. A new CIPP liner with enhanced insulation function was designed and its effectiveness was verified through numerical simulation, reducing the heat loss of aged pipes by 55.4%. This work provides a new perspective for DH pipe maintenance and contributes to energy conservation.
Article
Thermodynamics
Stanislav Chicherin, Amjad Anvari-Moghaddam
Summary: This study investigates variations and peak values of actual heat demand profiles in a centralized district heating network. It reveals that there is almost no weather correlation during warm months with supply temperatures exceeding 60 degrees C, and that thermal inertia of buildings affects their behavior differently in terms of needed space heating. By using precise heat demand data to design thermal energy storage units or district heating plants, DH operators can reduce energy prices and save energy fees for end-users by implementing weighted moving average strategies and advanced control techniques.
Article
Energy & Fuels
Anna Volkova, Ieva Pakere, Lina Murauskaite, Pei Huang, Kertu Lepiksaar, Xinxing Zhang
Summary: The 5th Generation District Heating and Cooling (5GDHC) network offers numerous advantages including integration of low-temperature resources, bi-directional operation, decentralised energy flows, and potential energy sharing. This study evaluates the prospects of implementing 5GDHC systems in the Baltic states and identifies Lithuania as having the most favorable conditions for implementation, while Estonia shows the greatest potential for heat pumps and excess heat utilization in 5GDHC systems.
Article
Thermodynamics
Tao Huang, Xiaochen Yang, Svend Svendsen
Article
Construction & Building Technology
Xiaochen Yang, Svend Svendsen
ENERGY AND BUILDINGS
(2020)
Article
Energy & Fuels
Michele Tunzi, Matthieu Ruysschaert, Svend Svendsen, Kevin Michael Smith
Article
Energy & Fuels
Fangtian Sun, Yonghua Xie, Svend Svendsen, Lin Fu
Article
Thermodynamics
Theofanis Benakopoulos, Michele Tunzi, Robbe Salenbien, Dirk Vanhoudt, Svend Svendsen
Summary: This study demonstrates the use of a chemical sterilisation method to eliminate the risk of Legionella in a domestic hot-water system, allowing for a reduction in circulation temperature to meet comfort requirements. Three temperature operation strategies were tested in the circulation loop, resulting in minimized Legionella concentration.
Article
Thermodynamics
Dorte Skaarup Ostergaard, Michele Tunzi, Svend Svendsen
Summary: The study investigated the best-case scenarios of building heating installations and found a gap between the well-functioning systems in apartment buildings and the future temperature targets. Single-family dwellings were closer to the targeted temperatures compared to apartment buildings, indicating room for improvement in existing buildings connected to new district heating systems in Europe.
Article
Thermodynamics
Theofanis Benakopoulos, Michele Tunzi, Robbe Salenbien, Svend Svendsen
Summary: This study investigated the potential of minimizing the supply temperature of the radiator system to stimulate the use of all the available radiators in each apartment, aiming to achieve higher thermal comfort. The investigation showed that under the minimum supply temperature and a sufficient hydraulic balance, the required heat could only be delivered if all the available radiators were used. By appropriately setting the balancing valves in each riser, a good hydraulic balance could be secured.
Article
Energy & Fuels
Theofanis Benakopoulos, William Vergo, Michele Tunzi, Robbe Salenbien, Svend Svendsen
Summary: This article presents three recommended solutions for new DHW systems to operate at low temperatures, including limiting heating power in DHW tanks, redirecting return flow to low-temperature space heating systems, and using micro-booster heat pump systems. These solutions can help reduce return temperatures and facilitate the transition to low-temperature district heating.
Article
Energy & Fuels
Michele Tunzi, Dorte Skaarup ostergaard, Svend Svendsen
Summary: Automated hydronic balancing is crucial in space heating systems, and the innovative electronic radiator thermostat demonstrated effective control and balance in the field results. The new thermostat successfully improved the temperature difference between supply and return, contributing to optimized heating performance.
Article
Energy & Fuels
Jan Eric Thorsen, Svend Svendsen, Kevin Michael Smith, Torben Ommen, Morten Skov
Summary: The concept of Circulation Booster aims to obtain low district heating return temperatures by boosting the domestic hot water circulation temperature through a heat pump and direct heat exchange, addressing the challenge posed by high circulation loss in domestic hot water systems.
Review
Thermodynamics
Dorte Skaarup Ostergaard, Kevin Michael Smith, Michele Tunzi, Svend Svendsen
Summary: This paper provides a comprehensive review of low-temperature heating, discussing its feasibility, temperature demands, and methods for reducing supply and return temperatures. It recommends key measures such as automatic balancing systems, novel solutions for domestic hot water supply, and digitally-enabled performance monitoring and optimal control.
Article
Green & Sustainable Science & Technology
Alicja Siuta-Olcha, Tomasz Cholewa, Miroslaw Gomolka, Piotr Kolodziej, Dorte Skaarup Ostergaard, Svend Svendsen
Summary: This paper presents the results of several years of field research on the modernization of existing district heating systems in 13 multi-family buildings. The study showed that decommissioning bifunctional area substations and using compact heat exchanger thermal stations with weather automation can significantly improve energy efficiency.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Thermodynamics
Theofanis Benakopoulos, William Vergo, Michele Tunzi, Robbe Salenbien, Jakub Kolarik, Svend Svendsen
Summary: This study investigates the impact of changing the control of the heating system in a typical office building from continuous high-temperature operation to high-temperature intermittent heating or continuous low-temperature operation on energy and cost savings. The results show that continuous low-temperature operation can achieve significant energy and cost reductions.
Article
Thermodynamics
Abdelkarim Tahiri, Kevin Michael Smith, Jan Eric Thorsen, Christian Anker Hviid, Svend Svendsen
Summary: This paper proposes two novel control concepts to optimize the charging of domestic hot water (DHW) tanks in large buildings supplied by district heating systems. The first concept employs a smart energy meter, while the second concept uses staged proportional gain with an added temperature sensor. By implementing these control methods, comfort and hygienic requirements are met, and energy consumption and total flow are reduced.
Article
Thermodynamics
Michele Tunzi, Theofanis Benakopoulos, Qinjiang Yang, Svend Svendsen
Summary: Ensuring low operating temperatures in district heating networks is crucial for the green transition towards 4th generation district heating (4GDH). Digitalizing the demand side by monitoring heating systems and improving operations can provide new opportunities for building services and achieve expected comfort in existing buildings with lower temperatures. This study investigated the integration of data from heat cost allocators, district heating energy meters, and temperature sensors to improve space heating system operations, with positive results in Danish multi-family buildings.
Article
Thermodynamics
Yong Cheng, Fukai Song, Lei Fu, Saishuai Dai, Zhiming Yuan, Atilla Incecik
Summary: This paper investigates the accessibility of wave energy absorption by a dual-pontoon floating breakwater integrated with hybrid-type wave energy converters (WECs) and proposes a hydraulic-pneumatic complementary energy extraction method. The performance of the system is validated through experiments and comparative analysis.
Article
Thermodynamics
Jing Gao, Chao Wang, Zhanwu Wang, Jin Lin, Runkai Zhang, Xin Wu, Guangyin Xu, Zhenfeng Wang
Summary: This study aims to establish a new integrated method for biomass cogeneration project site selection, with a focus on the application of the model in Henan Province. By integrating Geographic Information System and Multiple Criterion Decision Making methods, the study conducts site selection in two stages, providing a theoretical reference for the construction of biomass cogeneration projects.
Article
Thermodynamics
Mert Temiz, Ibrahim Dincer
Summary: The current study presents a hybrid small modular nuclear reactor and solar-based system for sustainable communities, integrating floating and bifacial photovoltaic arrays with a small modular reactor. The system efficiently generates power, hydrogen, ammonia, freshwater, and heat for residential, agricultural, and aquaculture facilities. Thermodynamic analysis shows high energy and exergy efficiencies, as well as large-scale ammonia production meeting the needs of metropolitan areas. The hybridization of nuclear and solar technologies offers advantages of reliability, environmental friendliness, and cost efficiency compared to renewable-alone and fossil-based systems.
Editorial Material
Thermodynamics
Wojciech Stanek, Wojciech Adamczyk
Article
Thermodynamics
Desheng Xu, Yanfeng Li, Tianmei Du, Hua Zhong, Youbo Huang, Lei Li, Xiangling Duanmu
Summary: This study investigates the optimization of hybrid mechanical-natural ventilation for smoke control in complex metro stations. The results show that atrium fires are more significantly impacted by outdoor temperature variations compared to concourse/platform fires. The gathered high-temperature smoke inside the atrium can reach up to 900 K under a 5 MW train fire energy release. The findings provide crucial engineering insights into integrating weather data and adaptable ventilation protocols for smoke prevention/mitigation.
Article
Thermodynamics
Da Guo, Heping Xie, Mingzhong Gao, Jianan Li, Zhiqiang He, Ling Chen, Cong Li, Le Zhao, Dingming Wang, Yiwei Zhang, Xin Fang, Guikang Liu, Zhongya Zhou, Lin Dai
Summary: This study proposes a new in-situ pressure-preserved coring tool and elaborates its pressure-preserving mechanism. The experimental and field test results demonstrate that this tool has a high pressure-preservation capability and can maintain a stable pressure in deep wells. This study provides a theoretical framework and design standards for the development of similar technologies.
Article
Thermodynamics
Aolin Lai, Qunwei Wang
Summary: This study assesses the impact of China's de-capacity policy on renewable energy development efficiency (REDE) using the Global-MSBM model and the difference-in-differences method. The findings indicate that the policy significantly enhances REDE, promoting technological advancements and marketization. Moreover, regions with stricter environmental regulations experience a higher impact.
Article
Thermodynamics
Mostafa Ghasemi, Hegazy Rezk
Summary: This study utilizes fuzzy modeling and optimization to enhance the performance of microbial fuel cells (MFCs). By simulating and analyzing experimental data sets, the ideal parameter values for increasing power density, COD elimination, and coulombic efficiency were determined. The results demonstrate that the fuzzy model and optimization methods can significantly improve the performance of MFCs.
Article
Thermodynamics
Zhang Ruan, Lianzhong Huang, Kai Wang, Ranqi Ma, Zhongyi Wang, Rui Zhang, Haoyang Zhao, Cong Wang
Summary: This paper proposes a grey box model for fuel consumption prediction of wing-diesel hybrid vessels based on feature construction. By using both parallel and series grey box modeling methods and six machine learning algorithms, twelve combinations of prediction models are established. A feature construction method based on the aerodynamic performance of the wing and the energy relationship of the hybrid system is introduced. The best combination is obtained by considering the root mean square error, and it shows improved accuracy compared to the white box model. The proposed grey box model can accurately predict the daily fuel consumption of wing-diesel hybrid vessels, contributing to operational optimization and the greenization and decarbonization of the shipping industry.
Article
Thermodynamics
Huayi Chang, Nico Heerink, Junbiao Zhang, Ke He
Summary: This study examines the interaction between off-farm employment decisions between couples and household clean energy consumption in rural China, and finds that two-paycheck households are more likely to consume clean energy. The off-farm employment of women is a key factor driving household clean energy consumption to a higher level, with wage-employed wives having a stronger influence on these decisions than self-employed ones.
Article
Thermodynamics
Hanguan Wen, Xiufeng Liu, Ming Yang, Bo Lei, Xu Cheng, Zhe Chen
Summary: Demand-side management is crucial to smart energy systems. This paper proposes a data-driven approach to understand the relationship between energy consumption patterns and household characteristics for better DSM services. The proposed method uses a clustering algorithm to generate optimal customer groups for DSM and a deep learning model for training. The model can predict the possibility of DSM membership for a given household. The results demonstrate the usefulness of weekly energy consumption data and household socio-demographic information for distinguishing consumer groups and the potential for targeted DSM strategies.
Article
Thermodynamics
Xinglan Hou, Xiuping Zhong, Shuaishuai Nie, Yafei Wang, Guigang Tu, Yingrui Ma, Kunyan Liu, Chen Chen
Summary: This study explores the feasibility of utilizing a multi-level horizontal branch well heat recovery system in the Qiabuqia geothermal field. The research systematically investigates the effects of various engineering parameters on production temperature, establishes mathematical models to describe their relationships, and evaluates the economic viability of the system. The findings demonstrate the significant economic feasibility of the multi-level branch well system.
Article
Thermodynamics
Longxin Zhang, Songtao Wang, Site Hu
Summary: This investigation reveals the influence of tip leakage flow on the modern transonic rotor and finds that the increase of tip clearance size leads to a decline in rotor performance. However, an optimal tip clearance size can extend the rotor's stall margin.
Article
Thermodynamics
Kristian Gjoka, Behzad Rismanchi, Robert H. Crawford
Summary: This paper proposes a framework for assessing the performance of 5GDHC systems and demonstrates it through a case study in a university campus in Melbourne, Australia. The results show that 5GDHC systems are a cost-effective and environmentally viable solution in mild climates, and their successful implementation in Australia can create new market opportunities and potential adoption in other countries with similar climatic conditions.
Article
Thermodynamics
Jianwei Li, Guotai Wang, Panpan Yang, Yongshuang Wen, Leian Zhang, Rujun Song, Chengwei Hou
Summary: This study proposes an orientation-adaptive electromagnetic energy harvester by introducing a rotatable bluff body, which allows for self-regulation to cater for changing wind flow direction. Experimental results show that the output power of the energy harvester can be greatly enhanced with increased rotatory inertia of the rotating bluff body, providing a promising solution for harnessing wind-induced vibration energy.
