Thermally activated building envelopes(TABEs)are multifunctional component that combines structural and energy properties.Based on re-examining the heat charging processes,an arc-shaped metal-fin-enhanced TABE(Arc-fin...Thermally activated building envelopes(TABEs)are multifunctional component that combines structural and energy properties.Based on re-examining the heat charging processes,an arc-shaped metal-fin-enhanced TABE(Arc-finTABE)with directional heat charging features is proposed to optimize the thermal barrier formation process.A comprehensive parameterized analysis is conducted based on a validated mathematical model to explore the influence of 5 fin-structure design parameters and the static insulation thickness.Results verified that the directional charging strengthening fins can improve transient thermal performances of Arc-finATBE and enlarge horizontal and vertical sizes of the thermal energy accumulation area surrounding the pipeline,while the maximum growth in extra heat loss is less than 3.17%.From the perspective of promoting heat injection into expected areas,the straight main fin configurations with the angle of main fins of 30°,shank length ratio of 0.4 and no leftward mounted fins are preferred in load-reduction mode,while the angle of main fins of 150°,shank length ratio of 0.8 and multiple fin designs,especially with one of the main fins horizontally toward the indoor side,are more favorable in auxiliary-heating mode.Besides,it is recommended to add one arc-shaped branch fin to each main fin to achieve a balance between performance improvement and material usage.Moreover,branch fins with larger arc angles are preferred in auxiliary-heating mode,while smaller arc angles are conducive to injecting heat into the wall along main fins in load-reduction mode and preventing the heat near the inner surface from being extracted.Under the direct influence of the strengthened invisible thermal barrier,Arc-finTABEs can reduce the amount of static insulation layer by 20%–80%while achieving equivalent thermal performances as conventional high-performance walls.展开更多
Optimized fin arrangement and dimension of heat exchanger can improve the maximum output power of thermoelectric generator(TEG)system which converts the wasted heat into electricity with thermoelectric modules(TEMs).C...Optimized fin arrangement and dimension of heat exchanger can improve the maximum output power of thermoelectric generator(TEG)system which converts the wasted heat into electricity with thermoelectric modules(TEMs).Considering that the geometric symmetry contributes to the temperature uniformity improvement and convenient TEMs arrangement,a low-backpressure TEG system based on a polyhedral-shape heat exchanger was developed.To assess the effect of inner topology and fin parameters on the heat transfer and output power of the TEG system,a realizable k-?turbulence based numerical model was established and validated to perform numerical simulations.The results demonstrate that increasing fin length,fin width and fin intersection angle are beneficial to the average surface temperature,temperature distribution uniformity and maximum output power of the TEG system.Moreover,decreasing fin spacing distance contributes to the enhanced average surface temperature and maximum power of TEG system,and has insignificant effect on its temperature uniformity.The inserted fins with optimal length,width,intersection angle and spacing distance enhance higher output power,whereas result in increasing backpressure.The maximum difference between the experimental and simulation results is 3.2%,which validates the feasibility of the established numerical model.It also provides a theoretical reference to the optimal design and performance analysis of low-backpressure TEG systems used in automobile exhaust heat recovery.展开更多
基金co-sponsored by the National Natural Science Foundation of China(No.52208103)Fundamental Research Funds for the Central Universities(No.JZ2024HGTB0229)+2 种基金Opening Fund of Anhui Province Key Laboratory of Intelligent Building&Building Energy Saving(No.IBES2024KF05,IBES2024ZR03)Anhui Province University Outstanding Scientific Research and Innovation Team(No.2022AH010021)Scientific Research and Cultivation Project of Anhui Jianzhu University(No.2021XMK04).
文摘Thermally activated building envelopes(TABEs)are multifunctional component that combines structural and energy properties.Based on re-examining the heat charging processes,an arc-shaped metal-fin-enhanced TABE(Arc-finTABE)with directional heat charging features is proposed to optimize the thermal barrier formation process.A comprehensive parameterized analysis is conducted based on a validated mathematical model to explore the influence of 5 fin-structure design parameters and the static insulation thickness.Results verified that the directional charging strengthening fins can improve transient thermal performances of Arc-finATBE and enlarge horizontal and vertical sizes of the thermal energy accumulation area surrounding the pipeline,while the maximum growth in extra heat loss is less than 3.17%.From the perspective of promoting heat injection into expected areas,the straight main fin configurations with the angle of main fins of 30°,shank length ratio of 0.4 and no leftward mounted fins are preferred in load-reduction mode,while the angle of main fins of 150°,shank length ratio of 0.8 and multiple fin designs,especially with one of the main fins horizontally toward the indoor side,are more favorable in auxiliary-heating mode.Besides,it is recommended to add one arc-shaped branch fin to each main fin to achieve a balance between performance improvement and material usage.Moreover,branch fins with larger arc angles are preferred in auxiliary-heating mode,while smaller arc angles are conducive to injecting heat into the wall along main fins in load-reduction mode and preventing the heat near the inner surface from being extracted.Under the direct influence of the strengthened invisible thermal barrier,Arc-finTABEs can reduce the amount of static insulation layer by 20%–80%while achieving equivalent thermal performances as conventional high-performance walls.
基金supported by the National Natural Science Foundation of China(51977061,51407063,61903129)Open Foundation of Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System(HBSEES202205)。
文摘Optimized fin arrangement and dimension of heat exchanger can improve the maximum output power of thermoelectric generator(TEG)system which converts the wasted heat into electricity with thermoelectric modules(TEMs).Considering that the geometric symmetry contributes to the temperature uniformity improvement and convenient TEMs arrangement,a low-backpressure TEG system based on a polyhedral-shape heat exchanger was developed.To assess the effect of inner topology and fin parameters on the heat transfer and output power of the TEG system,a realizable k-?turbulence based numerical model was established and validated to perform numerical simulations.The results demonstrate that increasing fin length,fin width and fin intersection angle are beneficial to the average surface temperature,temperature distribution uniformity and maximum output power of the TEG system.Moreover,decreasing fin spacing distance contributes to the enhanced average surface temperature and maximum power of TEG system,and has insignificant effect on its temperature uniformity.The inserted fins with optimal length,width,intersection angle and spacing distance enhance higher output power,whereas result in increasing backpressure.The maximum difference between the experimental and simulation results is 3.2%,which validates the feasibility of the established numerical model.It also provides a theoretical reference to the optimal design and performance analysis of low-backpressure TEG systems used in automobile exhaust heat recovery.
