Article
Green & Sustainable Science & Technology
Safak Atas, Ilhan Ceylan, Osman Egemen Timar
Summary: The aim of this study was to enhance the efficiency of heat pump systems commonly used for heating in winter. A combined system was created by integrating the heat pump system, solar air collectors, and a heat recovery device. The utilization of these systems together prevented the decrease in energy efficiency that may occur over the course of a day and improved their overall efficiency.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2023)
Article
Thermodynamics
Xiaoya Jia, Guoyuan Ma, Feng Zhou, Shuailing Liu, Guoqiang Wu, Qiuyu Sui
Summary: The novel dual-cylinder rotary compressor used in the PEAHP system in cold zone areas of China has shown to significantly improve heating/cooling capacities and COP values by increasing return air volume flow rate. The system demonstrates great applicability for ultra-low energy buildings in winter, with substantial enhancements in performance compared to traditional systems.
APPLIED THERMAL ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
T. Zhang, Y. F. Zhang, Z. R. Shi, Q. F. Li, J. Y. Cai
Summary: A hybrid PV/T collector/evaporator was designed and a hybrid system named PV-SAHP/GHP was proposed. Outdoor experiments were conducted to compare the operating characteristics of different modes. The results showed that the GHP-PV/T mode had satisfactory energy-saving effect while the PV-SAHP mode met the temperature demand but had unsatisfactory energy conservation effect. It is recommended to operate the GHP-PV/T mode during intense radiation and the PV-SAHP mode otherwise to balance the thermal performance and energy-saving benefits.
Article
Green & Sustainable Science & Technology
Yunhai Li, Zhaomeng Li, Yi Fan, Cheng Zeng, Yu Cui, Xudong Zhao, Jing Li, Ying Chen, Jianyong Chen, Chao Shen
Summary: Heat pumps (HPs) are important for global carbon reduction and carbon neutrality, but they have performance issues in cold climates. A two-stage heat recovery heat pump (THRHP) was developed to improve COP and energy consumption during defrosting. The optimized THRHP prototype achieved a heating capacity of 32.3 kW, generated 4 m3/h hot water at 55 degrees C with COP of 2.57 at outdoor temperature of 0 degrees C, and consumed only 0.46 kW and 4 mins during defrosting at -6 degrees C. This research provides insights and optimal control strategies for better THRHP performance, promoting the adoption of HPs and carbon-neutrality goals.
Article
Thermodynamics
Benzhi Hou, Yihua Zheng, Luyi Xing, Qinglu Song
Summary: The performance of thermoelectric heat pumps is enhanced by air recirculation and regenerative energy recovery. Experimental results show that the COP of the air recirculation TEHP is as high as about 3.7, and the COP with recirculation is 51-73% higher than without recirculation. The combination of regenerative heat recovery and air recirculation further improves the energy efficiency of the heat exchanger test system.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Shuailing Liu, Guoyuan Ma, Xiaoya Jia, Shuxue Xu, Guoqiang Wu, Yumei Zhang
Summary: By analyzing the energy transfer process, a novel building ventilator with an exhaust air heat pump enhanced by a pump-driven loop heat pipe system was proposed and compared with other systems. The thermal performance of the prototype was studied under different operating modes, and the energy-saving potential in ultra-low energy buildings was analyzed. Results showed the composite system had the highest energy efficiency ratio and could solve the energy recovery attenuation problem. It also had great applicability and achieved significant energy savings in different locations.
Article
Energy & Fuels
Tao Zhang, Yufan Zhang, Zhengrong Shi, Gang Pei, Jingyong Cai
Summary: Integrating passive and active heat transfer means in PV/T applications can solve freezing and corroding problems. The switching time of the hybrid system is rarely reported. A numerical model was developed to investigate the switching times based on thermal and exergy efficiency. The results indicate that the hybrid system needs to switch between modes based on efficiency criteria.
Article
Thermodynamics
Sheng Zhang, Weigeng Yun, Zhang Lin
Summary: This study proposes an integrated system of exhaust air heat pump and advanced air distribution to efficiently provide outdoor air. The system saves energy through various mechanisms and shows significant energy savings compared with traditional systems.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Wuyan Li, Xianting Li, Yijun Gao, Wenxing Shi
Summary: A novel thermo-economic coupled evaluation model for the run-around heat recovery system is proposed in this study, and a site investigation is performed for model validation. The simulation results indicate that the lifecycle profitability of the system mainly depends on its heat recovery and initial investment. The optimal design scheme and regional adaptability in China are evaluated.
Article
Thermodynamics
Yuan Wei, Shuilong Liu, Jianlin Yu
Summary: This paper proposes a vapor injection heat pump cycle with indirect heat recovery, which improves the performance of the cycle by adding a sub-cooler and an evaporator. The results show that the cycle has higher heating capacity and coefficient of performance under the same operating conditions. Additionally, lower ambient temperatures and higher fresh air ratio can also enhance the performance of the cycle.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2022)
Article
Thermodynamics
Z. Y. Xu, J. T. Gao, Bin Hu, R. Z. Wang
Summary: The study compares the efficiency of compression and absorption heat pumps, revealing that compression heat pumps have higher coefficient of performance but lower exergy efficiency, while absorption heat pumps are more effective at higher temperature differentials.
Article
Construction & Building Technology
Xiaoya Jia, Guoyuan Ma, Feng Zhou, Shuailing Liu, Guoqiang Wu, Qiuyu Sui
Summary: The study introduces a novel dual-cylinder rotary compressor to improve the performance of exhaust air heat recovery system in residential buildings. By experimenting and analyzing the system under different conditions, an optimized method is proposed and an annual energy efficient operation plan is developed, with calculations made for three typical countries/organizations. The results show significant improvement in system COP by using a mixed air supply method in winter and increasing ventilation volume flow rate in summer.
JOURNAL OF BUILDING ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Yubo Wang, Zhenhua Quan, Yaohua Zhao, Lincheng Wang, Heran Jing
Summary: This paper studies the feasibility of a coupled air and ground source heat pump system with energy storage for building energy supply. The system utilizes auxiliary heat sources to achieve high-performance heating and energy storage, while optimizing defrosting control and soil heat balance. It has economic and environmental advantages.
Article
Thermodynamics
Dongwei Zhang, Chenglei Fang, Zhao Gao, Xin Wang, Chao Shen, Hang Li
Summary: Wastewater heat pump systems are extensively researched for their energy conservation and environmental benefits. This study examines the use of transcritical CO2 heat pumps for wastewater heat recovery, and compares them with regenerative boiler systems. The results show that the regenerative heat pump system can save 76.67% more energy than the regenerative boiler system, with reduced carbon dioxide emissions and lower life cycle costs. With government subsidies, the regenerative heat pump system can achieve a higher annual average cost difference. This research promotes the implementation of transcritical CO2 heat pumps in wastewater heat recovery technology.
APPLIED THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Piotr Kowalski, Pawel Szalanski, Wojciech Cepinski
Summary: The paper analyzes the application of an air-to-water electric compressor heat pump for recovering waste heat in a typical multifamily residential building for space heating, showing great potential in energy and environmental aspects. The system's energy performance benefits depend on system parameters and location, with lower heating system temperatures being more energy-efficient. Additionally, implementing temperature limitations on heat pump operation can improve efficiency.
Article
Thermodynamics
Pengcheng Zhao, Jingang Wang, Liming Sun, Yun Li, Haiting Xia, Wei He
Summary: The production of green hydrogen through water electrolysis is crucial for renewable energy utilization and decarbonization. This research explores the optimal electrode configuration and system design of compactly-assembled industrial electrolyzer. The findings provide valuable insights for industrial application of water electrolysis equipment.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
V. Baiju, P. Abhishek, S. Harikrishnan
Summary: Thermally driven adsorption desalination systems (ADS) have gained attention as an eco-friendly solution for water scarcity. However, they face challenges related to low water productivity and scalability. To overcome these challenges, integrating ADS with other desalination technologies can create a small-scale hybrid system. This study proposes integrating ADS with a Thermo Electric Dehumidification (TED) unit to enhance its performance.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
C. X. He, Y. H. Liu, X. Y. Huang, S. B. Wan, Q. Chen, J. Sun, T. S. Zhao
Summary: A decentralized centroid multi-path RC network model is constructed to improve the temperature prediction accuracy compared to traditional RC models. By incorporating multiple heat flow paths and decentralizing thermal capacity, a more accurate prediction is achieved.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Chaoying Li, Meng Wang, Nana Li, Di Gu, Chao Yan, Dandan Yuan, Hong Jiang, Baohui Wang, Xirui Wang
Summary: There is an urgent need to shift away from heavy dependence on fossil fuels and embrace renewable energy sources, particularly in the energy-intensive oil refining process. This study presents an innovative concept called the Solar Oil Refinery, which applies solar energy in oil refining. A solar multi-energies-driven hybrid chemical oil refining system that utilizes solar pyrolysis and electrolysis has been developed, significantly improving solar utilization efficiency, cracking rate, and hydrogen yield.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Chao Ma, Guanghui Wang, Dingbiao Wang, Xu Peng, Yushen Yang, Xinxin Liu, Chongrui Yang, Jiaheng Chen
Summary: This study proposes a bio-inspired fish-tail wind rotor to improve the wind power efficiency of the traditional Savonius rotor. Through transient simulations and orthogonal experiments, the key factors affecting the performance are identified. A response surface model is constructed to optimize the power coefficient, resulting in an improvement of 9.4% and 6.6% compared to the Savonius rotor.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Sina Bahmanziari, Abbas-Ali Zamani
Summary: This paper proposes a new framework for improving electrical energy harvesting from piezoelectric smart tiles through a combination of magnetic plucking, mechanical impact, and mechanical vibration force mechanisms. Experimental results demonstrate a significant increase in energy yield and average energy harvesting time compared to other mechanisms.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Nanjiang Dong, Tao Zhang, Rui Wang
Summary: This study establishes a multiobjective mixed-variable configuration optimization model for a comprehensive combined cooling, heating, and power energy system, and proposes an efficient generating operator to optimize this model. The experimental results show that the proposed algorithm performs better than other state-of-the-art algorithms.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Ahmed E. Mansy, Eman A. El Desouky, Tarek H. Taha, M. A. Abu-Saied, Hamada El-Gendi, Ranya A. Amer, Zhen-Yu Tian
Summary: This study aims to convert office paper waste into bioethanol through a sustainable pathway. The results show that physiochemical and enzymatic hydrolysis of the waste can yield a high glucose concentration. The optimal conditions were determined using the Box-Behnken design, and a blended membrane was used for ethanol purification.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Sven Klute, Marcus Budt, Mathias van Beek, Christian Doetsch
Summary: Heat pumps are crucial for decarbonizing heat supply, and steam generating heat pumps have the potential to decarbonize the industrial sector. This paper presents the current state, technical and economic data, and modeling principles of steam generating heat pumps.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Le Zhang, To-Hung Tsui, Yen Wah Tong, Pruk Aggarangsi, Ronghou Liu
Summary: This study investigates the effectiveness of a current-carrying-coil-based magnetic field in promoting anaerobic digestion of chicken manure. The results show that the applied magnetic field increases methane yield, decreases carbon dioxide production, and reduces the concentration of ammonia nitrogen. Microbial community analysis reveals the enrichment of certain methanogenic genera and enhanced metabolic pathways. Pilot-scale experiments confirm the technical effectiveness of the magnetic field assistance in enhancing anaerobic digestion of chicken manure.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Bo Chen, Ruiqing Ma, Yang Zhou, Rui Ma, Wentao Jiang, Fan Yang
Summary: This paper presents an advanced energy management strategy for fuel cell hybrid electric heavy-duty vehicles, focusing on speed planning and energy allocation. By utilizing predictive co-optimization control, this strategy ensures safe inter-vehicle distance and minimizes energy demand. Simulation results demonstrate the effectiveness of the proposed method in reducing fuel cell degradation cost and overall operation cost.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Fabio Fatigati, Roberto Cipollone
Summary: Organic Rankine Cycle-based microcogeneration systems that use solar sources to generate electricity and hot water can help reduce CO2 emissions in residential energy-intensive sectors. The adoption of a recuperative heat exchanger in these systems improves efficiency, reduces thermal power requirements, and saves on electricity costs.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Lipeng He, Renwen Liu, Xuejin Liu, Xiaotian Zheng, Limin Zhang, Jieqiong Lin
Summary: This research proposes a piezoelectric-electromagnetic hybrid energy harvester (PEHEH) for low-frequency wave motion and self-sensing wave environment monitoring. The PEHEH shows promising power output and the ability to self-power and self-sense the wave environment.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Shangling Chu, Yang Liu, Zipeng Xu, Heng Zhang, Haiping Chen, Dan Gao
Summary: This paper studies a distributed energy system integrated with solar and natural gas, analyzes the impact of different parameters on its energy utilization and emissions reduction, and obtains the optimal solution through an optimization algorithm. The results show that compared to traditional separation production systems, this integrated system achieves higher energy utilization and greater reduction in carbon emissions.
ENERGY CONVERSION AND MANAGEMENT
(2024)
Article
Thermodynamics
Qingpu Li, Yaqi Ding, Guangming Chen, Yongmei Xuan, Neng Gao, Nian Li, Xinyue Hao
Summary: This paper proposes and studies a piston-type thermally-driven pump with a structure similar to a linear compressor, aiming to eliminate the high-quality energy consumption of existing pumps and replace mechanical pumps. The coupling mechanism of working fluid flow and element dimension is analyzed based on force analysis, and experimental data analysis is used to determine the pump operation stroke. Theoretical simulation is conducted to analyze the correlation mechanism of the piston assembly. The research shows that the thermally-driven pump can greatly reduce power consumption and has potential for industrial applications.
ENERGY CONVERSION AND MANAGEMENT
(2024)