Article
Energy & Fuels
Evangelos Bellos, Petros Iliadis, Christos Papalexis, Renos Rotas, Nikos Nikolopoulos, Elias Kosmatopoulos, Christian Halmdienst
Summary: This study investigates a district heating network with decentralized storage for hot water, using a schedule-based approach to control the charging of the system. The simulation is conducted using a component-based tool called INTEMA, which allows for high temporal resolution and adjustable time steps. The results show that the decentralized approach leads to energy savings of 18% and reduces thermal losses by 22% compared to a standard system.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Construction & Building Technology
Aleksandrs Zajacs, Raimonds Bogdanovics, Anastasija Zeiza-Seleznova, Rokas Valancius, Jurgis Zemitis
Summary: This study focuses on integrating small capacity prosumers into district heating networks. The challenge lies in the unpredictable fluctuations in cloud cover and pressure drops in the network for solar collector installations. An experimental prototype and a simulation model were developed to analyze options for improving feed-in temperature stability. The results show that cloud cover has a strong influence on the stability of collector outlet temperature.
SUSTAINABLE CITIES AND SOCIETY
(2022)
Article
Thermodynamics
Yanfeng Liu, Ting Mu, Xi Luo
Summary: Northwest China has abundant solar energy resources and a large demand for winter heating. This study developed a joint multi-objective optimization model for the equipment capacity and the diameters of the heating network pipes of a centralized solar district heating system. The results show that the solar heating system designed using this method has lower economic cost and higher environmental protection.
BUILDING SIMULATION
(2023)
Review
Multidisciplinary Sciences
Xiuqiang Li, Sujin Shao, Meijiao Huang, Shuyuan Zhang, Wanlin Guo
Summary: In recent years, sustainable energy development has become a major theme of research. The combination of solar heating and daytime radiative cooling has the potential to build a competitive strategy to alleviate current environmental and energy problems. However, there are still challenges such as narrow spectrum regulation range, low heating/cooling performance, and poor stability. To further promote this technology for real-world applications, the latest progress, technical features, bottlenecks, and future opportunities for the current integration of daytime radiative cooling and solar heating are summarized.
Article
Thermodynamics
S. Bordignon, D. Quaggiotto, J. Vivian, G. Emmi, M. De Carli, A. Zarrella
Summary: This study proposes a new technical solution for providing air conditioning, domestic hot water, and electricity to a small residential district in heating-dominant regions. The solution includes the use of high-efficiency ground source heat pump, booster heat pumps, and rooftop photovoltaic thermal panels. The proposed system achieves high performance and utilizes multiple energy sources effectively.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Green & Sustainable Science & Technology
Sapan Thapar
Summary: The growth of solar energy in India has been remarkable, surpassing 50 GW of installed capacity. However, most of the solar assets are centralized utility projects, with very few decentralized plants. This study compares centralized and decentralized solar projects in terms of economics, social impact, and technical aspects. The economic assessment shows competitive energy costs near the point of consumption for both types of plants after considering transmission losses and associated charges. On the technical side, a shifting solar curve is observed as the plant locations move from east to west, resulting in an extended window for solar power generation. While centralized projects exclude smaller participants and concentrate assets, decentralized plants promote community participation, generate more employment, and provide energy access for local communities. A balanced policy approach that promotes both types of project configurations is recommended.
Article
Energy & Fuels
Anna Duczkowska, Ewa Kulinska, Zbigniew Plutecki, Joanna Rut
Summary: This paper discusses the importance of biomass for energy production in Poland's energy policy. It presents the conditions related to using agricultural biomass for heating purposes and aims to assess its energy potential and effective use. The research uses data analysis, forecasting, and optimization methods to determine the most advantageous variant. The results include the potential of biomass, optimum location for storage and processing sites, and the frequency of transport to energy companies.
Review
Green & Sustainable Science & Technology
Robin Zeh, Bjorn Ohlsen, David Philipp, David Bertermann, Tim Kotz, Nikola Jocic, Volker Stockinger
Summary: Combining low temperature district heating and cooling networks (5GDHC) with very shallow geothermal energy potentials enables renewable heating and cooling for settlements up to entire city districts, with the flexibility to shift loads seasonally. The use of large-scale geothermal collector systems and other renewable heat sources enhances the overall efficiency and sustainability of the heating network.
Article
Green & Sustainable Science & Technology
Shiyao Li, Yiqun Pan, Peng Xu, Nan Zhang
Summary: The paper proposes a novel decentralized competitive energy system to facilitate the utilization of locally-produced energy and achieve supply-demand balance. Through a multi-layer system architecture and a money transaction protocol based on IOTA among devices, the peer-to-peer heating system outperforms conventional central heating systems in terms of user cost and system efficiency, as demonstrated by a case study and computer simulations.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Energy & Fuels
Yanfeng Liu, Deze Hu, Xi Luo, Ting Mu
Summary: Considering the abundance of solar energy resources and the dispersed building distribution in rural areas, deploying a centralized-decentralized hybrid solar heating system can achieve optimal heating results both technically and economically in rural Chinese areas.
Article
Thermodynamics
Saleh S. Meibodi, Fleur Loveridge
Summary: Energy geostructures are innovative engineering sub-structures that can be used for heat transfer and storage. They are primarily used in ground source heat pump systems, but there is potential for their integration into fifth generation district heating and cooling networks. Further research is needed to evaluate the advantages and potential of this integration.
Article
Thermodynamics
Ruichao Zhang, Dengjia Wang, Yanfeng Liu, Yaowen Chen, Jianhua Fan, Cong Song, Yingying Wang
Summary: The study found that the electric boiler is suitable for areas with abundant solar irradiation, with a required SF of over 85%, while the air source heat pump is better for areas with poor solar irradiation and a SF below 50%. Maintenance cost changes significantly affect the LCOH, with a greater impact when the SF is higher. Increasing the non-guaranteed rate for the air source heat pump can improve the overall economy of the system.
ENERGY CONVERSION AND MANAGEMENT
(2021)
Article
Thermodynamics
Lanhua Liu, Ruilin Wang, Yuhao Wang, Wenjia Li, Jian Sun, Yafei Guo, Wanjun Qu, Weiling Li, Chuanwen Zhao
Summary: The introduction of solar thermal energy and thermal energy storage can improve the performance and economy of combined cooling, heating and power (CCHP) systems. This study proposes a CCHP system integrated with solar thermal energy and thermal energy storage, which outperforms traditional systems in terms of performance and reduces the equivalent levelized cost of electricity through capacity adjustments and optimized operation strategies.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Green & Sustainable Science & Technology
Saeed Alqaed
Summary: This paper investigates the effect of using a polymeric phase change material (PCM) in a solar hot air collector on residential heating and cooling. The results show that increasing the collector length can raise the outflow air temperature, and the inlet air temperature has a significant effect on the outlet temperature. The use of PCM can reduce the outlet air temperature in the early hours of the day but enhance it in the last hours of the day. The system can heat a 95-m2 residential unit and provide 41% of the energy required.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Thermodynamics
Gamal Hashem, Khamid Mahkamov, Basim Belgasim, Nabil Elsharif, Irina Makhkamova
Summary: The study focuses on the development of a novel cooling system that utilizes solar thermal energy efficiently, combining a liquid piston engine and cooling machine. The system performance was evaluated under various operating conditions, showing promising results in terms of cooling capacity and engine efficiency.
ENERGY CONVERSION AND MANAGEMENT
(2021)
Article
Energy & Fuels
Daniel Tschopp, Adam R. Jensen, Janne Dragsted, Philip Ohnewein, Simon Furbo
Summary: This study analyzed the impact of view obstructions on diffuse irradiance distribution in fixed-tilt arrays and developed an anisotropic transposition model to calculate diffuse tilted irradiance. The validation showed that the model accurately captures the distinct shape of the diffuse irradiance distribution, indicating a strong effect of view obstructions for narrow row spacings and steep tilt angles.
Article
Energy & Fuels
Elsabet Nielsen, Sonja Becker-Hardt, Gerald Englmair, Weiqiang Kong, Simon Furbo
Summary: An experimental study on an air solar-driven open sorption system for comfort cooling was conducted, with the main components being a solar dehumidifier and a cold storage. Material investigation found the best desiccant for both components, while the system's usability in different climates was assessed. Results showed that a small porous silica gel was the optimal desiccant, and the system could effectively provide cool, dry air for comfort cooling in various climates.
Article
Construction & Building Technology
Changxing Zhang, Elsabet Nielsen, Jianhua Fan, Simon Furbo
Summary: This paper presents experimental investigations on the thermal behavior of a combined solar and ground source heat pump system in a single-family house. The study shows that the system performs well under different operating conditions, meeting the requirements for space heating and domestic hot water. The focus of the research is on the dynamic thermal behaviors of the heat storage, providing valuable insights for the integration of combi-storage in renewable heating systems.
ENERGY AND BUILDINGS
(2022)
Article
Energy & Fuels
Adam R. Jensen, Ioannis Sifnaios, Simon Furbo, Janne Dragsted
Summary: In this paper, an open source method for calculating self-shading in fields of two-axis tracking solar collectors of arbitrary geometry was developed and validated. The impact of latitude and collector aperture shape on annual shading loss was investigated.
Article
Energy & Fuels
Adam R. Jensen, Ioannis Sifnaios, Gideon P. Caringal, Simon Furbo, Janne Dragsted
Summary: Fresnel lenses are widely used in solar energy applications due to their reduced material usage, low cost, and high optical efficiency. This study investigated the world's first full-scale Fresnel lens solar collector field and found that peak efficiency was reduced by 11% compared to a new collector due to soiling and heat losses. The annual performance of the system was determined using a simulation model and validated with measurement data.
Article
Energy & Fuels
Gang Wang, Chao Xu, Gerald Englmair, Weiqiang Kong, Jianhua Fan, Simon Furbo, Gaosheng Wei
Summary: A flexible thermal energy storage system with both short-term and long-term heat storage functions was investigated. Experimental and CFD simulation results showed that the system can release both sensible heat and latent heat flexibly, with different flow characteristics and thermal stratification in the tank. The study also found that the flow rate significantly affects the thermal characteristics during charging and discharging periods.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Energy & Fuels
Martin Andersen, Chris Bales, Jan-Olof Dalenback
Summary: One challenge in today's district heating systems is the high distribution heat loss. Lowering distribution temperatures and changing the distribution system can reduce operational and investment costs, improving the overall life cycle cost competitiveness of district heating systems.
Article
Green & Sustainable Science & Technology
Meng Gao, Jianhua Fan, Simon Furbo, Yutong Xiang
Summary: This paper investigates a glazed solar preheating collector wall through numerical simulation, exploring its influence on the environment and range of applications. The characteristics of internal flow and temperature distribution are obtained to aid in structural analysis and design. The optimized design shows higher exergy efficiency, thermal efficiency, and lower heat loss rate compared to traditional solar walls.
Article
Energy & Fuels
Gang Wang, Zhirong Liao, Chao Xu, Gerald Englmair, Weiqiang Kong, Jianhua Fan, Gaosheng Wei, Simon Furbo
Summary: This paper presents a numerical investigation on using sodium acetate trihydrate as a phase change material in heat storage. The study reveals that uneven flow distribution inside the heat storage can be eliminated through design optimization methods. The results show that changing the flow direction, inlet size, and adding a porous plate can improve the thermal performance of the heat storage.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Energy & Fuels
Xinyu Pan, Yutong Xiang, Meng Gao, Jianhua Fan, Simon Furbo, Dengjia Wang, Chao Xu
Summary: This study investigated the long-term thermal performance of a large-scale water pit thermal energy storage system in Dronninglund, Denmark. A modified 2D model was used to accurately predict the thermal performance of the system, which showed high storage efficiency and low thermal loss.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Thermodynamics
Adam R. Jensen, Ioannis Sifnaios, Bengt Perers, Jan Holst Rothmann, Soren D. Morch, Poul V. Jensen, Janne Dragsted, Simon Furbo
Summary: This study presents the design and performance of the Bronderslev hybrid plant, which is the world's first CSP-biomass plant to utilize waste heat. The plant successfully provides heat to the local district heating grid using a combination of solar collector field and biomass boilers, and the ORC system achieves high electrical efficiency. The results demonstrate the reliable operation of the hybrid plant and the potential of CSP-biomass hybridization.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Green & Sustainable Science & Technology
Evdoxia Paroutoglou, Peter Fojan, Leonid Gurevich, Simon Furbo, Jianhua Fan, Marc Medrano, Alireza Afshari
Summary: Latent heat thermal energy storage with Phase Change Materials (PCM) is a promising option for Thermal Energy Storage (TES) applications. This study developed a tubular encapsulation model and conducted a parametric analysis to optimize the system geometry and investigate the influence of internal and external fins on thermal conductivity. The results also showed that using PCM organic paraffin RT18 encapsulated in electrospun fiber matrices enabled rapid phase change processes.
Article
Energy & Fuels
Yutong Xiang, Meng Gao, Simon Furbo, Dengjia Wang, Zhiyong Tian, Jianhua Fan
Summary: This study presents a full-scale computational fluid dynamics model of PTES that includes water and soil regions, aiming to improve the accuracy of heat transfer calculation in multi-node models. The model is validated against measurements and shows good agreement in thermal stratification, energy flow, and soil temperature distribution.
JOURNAL OF ENERGY STORAGE
(2022)
Review
Energy & Fuels
Yutong Xiang, Zichan Xie, Simon Furbo, Dengjia Wang, Meng Gao, Jianhua Fan
Summary: Pit thermal energy storage (PTES) is a promising and affordable thermal storage technology for large-scale renewable energy applications. This paper evaluates 160 recent publications to identify the success factors and research gaps of PTES. The technical elements affecting PTES thermal properties are outlined, and numerical studies are categorized for systematic discussion. The current application status of PTES systems worldwide is summarized, with a focus on operational data. The review outlines progress and potential directions for PTES design and numerical studies by identifying research gaps that require further investigation.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Green & Sustainable Science & Technology
Yutong Xiang, Meng Gao, Simon Furbo, Jianhua Fan, Gang Wang, Zhiyong Tian, Dengjia Wang
Summary: This study analyzes the dynamic behavior of inlet mixing inside the PTES using a three-dimensional model and proposes two performance indicators to quantify the impact of inlet mixing. The results show that the penetration height has a power-law relation with the Reynold number, and the energy distribution ratio has a power-law relation with time in the region of a negative buoyancy jet. Empirical correlations are used to characterize the inflow mixing under various operating conditions.
