Pub Date : 2023-09-29DOI: 10.1080/23744731.2023.2263324
Eliot Crowe, Yimin Chen, Hayden Reeve, David Yuill, Amir Ebrahimifakhar, Yuxuan Chen, Lucas Troup, Amanda Smith, Jessica Granderson
Commercial building HVAC systems experience many sensing, mechanical, and control-related faults that increase energy consumption and impact occupant comfort. Fault detection & diagnostics (FDD) software has been demonstrated to identify and help diagnose these types of faults. Several studies have demonstrated FDD energy savings potential, but there is limited empirical data characterizing the quantity and type of faults reported by FDD tools. This paper presents results of an FDD fault reporting study, employing multi-year monitoring data for over 60,000 pieces of HVAC equipment, covering over 90 fault types, and using new metrics that we developed to characterize fault prevalence. Study results offer an unprecedented accounting of the quantity of faults reported, the most commonly occurring faults, and fault persistence. We find that 21 air handling unit (AHU) faults were reported on 20% or more AHUs in our dataset, and 18 AHU faults persisted for more than 20% of the time period covered by the data. On any given day, 40% of AHUs and 30% of air terminal units saw a reported fault of some kind. Based on in-depth analysis of these results we provide recommendations for building operators, FDD software developers, and researchers to enable more efficient commercial building operation.
{"title":"Empirical Analysis of the Prevalence of HVAC Faults in Commercial Buildings","authors":"Eliot Crowe, Yimin Chen, Hayden Reeve, David Yuill, Amir Ebrahimifakhar, Yuxuan Chen, Lucas Troup, Amanda Smith, Jessica Granderson","doi":"10.1080/23744731.2023.2263324","DOIUrl":"https://doi.org/10.1080/23744731.2023.2263324","url":null,"abstract":"Commercial building HVAC systems experience many sensing, mechanical, and control-related faults that increase energy consumption and impact occupant comfort. Fault detection & diagnostics (FDD) software has been demonstrated to identify and help diagnose these types of faults. Several studies have demonstrated FDD energy savings potential, but there is limited empirical data characterizing the quantity and type of faults reported by FDD tools. This paper presents results of an FDD fault reporting study, employing multi-year monitoring data for over 60,000 pieces of HVAC equipment, covering over 90 fault types, and using new metrics that we developed to characterize fault prevalence. Study results offer an unprecedented accounting of the quantity of faults reported, the most commonly occurring faults, and fault persistence. We find that 21 air handling unit (AHU) faults were reported on 20% or more AHUs in our dataset, and 18 AHU faults persisted for more than 20% of the time period covered by the data. On any given day, 40% of AHUs and 30% of air terminal units saw a reported fault of some kind. Based on in-depth analysis of these results we provide recommendations for building operators, FDD software developers, and researchers to enable more efficient commercial building operation.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-27DOI: 10.1080/23744731.2023.2261807
Kevin Autelitano, Michele Bolognini, Enrico de Angelis, Lorenzo Fagiano, Marco Scaioni
AbstractThe adoption of Unmanned Aerial Vehicles for energy efficiency assessment is a promising technique. Although there are some interesting ideas to automate the process, most of the operations are still done manually. An integrated methodology is presented to identify maintenance needs from both RGB and IR images collected with a commercial drone. The real building selected as case study is reconstructed in a 3D environment through Structure from Motion, while the infrared information is integrated and properly scaled on it to obtain a 3D point cloud model that provides, for each point: (i) information about its position in the space (ii) external surface temperature measured during data gathering phase. The point cloud is then segmented into the different sides of the envelope to identify each part of the façade and compared with a model that reconstructs the expected conditions of the building. This procedure enables the development of an automated pipeline to identify defects and failures in a building envelope and to suggest corrective actionsDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.
摘要采用无人机进行能源效率评估是一项很有前途的技术。尽管有一些有趣的想法可以实现流程自动化，但大多数操作仍然是手动完成的。提出了一种综合方法，从商用无人机收集的RGB和IR图像中识别维护需求。选取作为案例研究的真实建筑，通过Structure from Motion在三维环境中进行重建，同时对红外信息进行整合和适当缩放，得到三维点云模型，该模型为每个点提供:(i)其在空间中的位置信息(ii)数据采集阶段测量的外表面温度。然后将点云分割到围护结构的不同侧面，以识别立面的每个部分，并与重建建筑物预期条件的模型进行比较。此程序使开发自动化管道能够识别建筑围护结构中的缺陷和故障，并建议纠正措施。免责声明作为对作者和研究人员的服务，我们提供此版本的已接受手稿(AM)。在最终出版版本记录(VoR)之前，将对该手稿进行编辑、排版和审查。在制作和印前，可能会发现可能影响内容的错误，所有适用于期刊的法律免责声明也与这些版本有关。
{"title":"On the Use of Vision-based Drone Application to Building Digitalization, Diagnostics and Energy Efficiency Assessment <sup>*</sup>","authors":"Kevin Autelitano, Michele Bolognini, Enrico de Angelis, Lorenzo Fagiano, Marco Scaioni","doi":"10.1080/23744731.2023.2261807","DOIUrl":"https://doi.org/10.1080/23744731.2023.2261807","url":null,"abstract":"AbstractThe adoption of Unmanned Aerial Vehicles for energy efficiency assessment is a promising technique. Although there are some interesting ideas to automate the process, most of the operations are still done manually. An integrated methodology is presented to identify maintenance needs from both RGB and IR images collected with a commercial drone. The real building selected as case study is reconstructed in a 3D environment through Structure from Motion, while the infrared information is integrated and properly scaled on it to obtain a 3D point cloud model that provides, for each point: (i) information about its position in the space (ii) external surface temperature measured during data gathering phase. The point cloud is then segmented into the different sides of the envelope to identify each part of the façade and compared with a model that reconstructs the expected conditions of the building. This procedure enables the development of an automated pipeline to identify defects and failures in a building envelope and to suggest corrective actionsDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135535478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-01DOI: 10.1080/23744731.2023.2253084
Yuande Dai, Ziyu Wang, Jiahuan Wu, Chao Xu
The understanding of two-phase flow and heat transfer characteristics of refrigerants in tubes is important for guiding the design and optimization of heat exchangers. Based on the volume of fluid (VOF) multiphase model, this paper established a numerical model of R1234ze(E)/R152a (mass ratio of 0.4/0.6) flow boiling heat transfer in a horizontal smooth copper tube with an inner diameter of 6 mm and a length of 900 mm. The distribution of vapor volume fraction is obtained, and the influence of mass flux, heat flux, saturation temperature, and vapor quality on heat transfer coefficient (HTC) are studied. Bubble flow, plug flow, stratified flow, and wavy flow can be observed during the whole process and the fluid temperature increases along the tube. Local and time-averaged heat transfer coefficients and temperature distribution along the axial direction were studied. And the results indicate that the HTC decreases first and then increases with the augmentation of mass flux while increasing with the rise of heat flux. In addition, the HTC rises along with saturation temperature and decreases along with vapor quality. The largest related standard deviation between the simulation value and the testing data is 6.31%. Thus, the numerical simulation has a high level of accuracy.
{"title":"Numerical Simulation on Flow Boiling Heat Transfer of R1234ze(E)/R152a in a Horizontal Smooth Tube","authors":"Yuande Dai, Ziyu Wang, Jiahuan Wu, Chao Xu","doi":"10.1080/23744731.2023.2253084","DOIUrl":"https://doi.org/10.1080/23744731.2023.2253084","url":null,"abstract":"The understanding of two-phase flow and heat transfer characteristics of refrigerants in tubes is important for guiding the design and optimization of heat exchangers. Based on the volume of fluid (VOF) multiphase model, this paper established a numerical model of R1234ze(E)/R152a (mass ratio of 0.4/0.6) flow boiling heat transfer in a horizontal smooth copper tube with an inner diameter of 6 mm and a length of 900 mm. The distribution of vapor volume fraction is obtained, and the influence of mass flux, heat flux, saturation temperature, and vapor quality on heat transfer coefficient (HTC) are studied. Bubble flow, plug flow, stratified flow, and wavy flow can be observed during the whole process and the fluid temperature increases along the tube. Local and time-averaged heat transfer coefficients and temperature distribution along the axial direction were studied. And the results indicate that the HTC decreases first and then increases with the augmentation of mass flux while increasing with the rise of heat flux. In addition, the HTC rises along with saturation temperature and decreases along with vapor quality. The largest related standard deviation between the simulation value and the testing data is 6.31%. Thus, the numerical simulation has a high level of accuracy.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49315173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.1080/23744731.2023.2253087
D. Villa, J. Quiroz
Renewable microgrids are sustainable, resilient solutions to mitigate and adapt to climate change. Making electric loads nearly 100% available (i.e., power remains on) during outages increases cost. Near 100% availability is required when human life or high-cost assets are involved, but availability can be reduced for less consequential loads leading to lower costs. This study analyses costs for photo-voltaic and lithium-ion battery microgrids with availability ranging from 0–99%. We develop a methodology to analyse three Puerto Rican coastal communities. We consider power outage effects for hurricanes, earthquakes, and everyday outages. The results show cost versus availability from 0–99%. There is 27–31% cost reduction at 80% availability in comparison to 99% availability. A regression model of microgrid availability versus three ratios: 1) the annual generation to demand ratio, 2) storage to interruption energy ratio, and 3) peak storage to load ratio produced a coefficient of determination of 0.99949 with 70% of the data used for training and 30% for testing. The results can therefore be extended to other coastal Puerto Rican communities of varying sizes that have ratios within the ranges analysed in this study. This can empower decision makers to rapidly analyse designs that have availabilities well below 100%.
{"title":"Reducing Microgrid Availability to Reduce Costs for Coastal Puerto Rican Communities","authors":"D. Villa, J. Quiroz","doi":"10.1080/23744731.2023.2253087","DOIUrl":"https://doi.org/10.1080/23744731.2023.2253087","url":null,"abstract":"Renewable microgrids are sustainable, resilient solutions to mitigate and adapt to climate change. Making electric loads nearly 100% available (i.e., power remains on) during outages increases cost. Near 100% availability is required when human life or high-cost assets are involved, but availability can be reduced for less consequential loads leading to lower costs. This study analyses costs for photo-voltaic and lithium-ion battery microgrids with availability ranging from 0–99%. We develop a methodology to analyse three Puerto Rican coastal communities. We consider power outage effects for hurricanes, earthquakes, and everyday outages. The results show cost versus availability from 0–99%. There is 27–31% cost reduction at 80% availability in comparison to 99% availability. A regression model of microgrid availability versus three ratios: 1) the annual generation to demand ratio, 2) storage to interruption energy ratio, and 3) peak storage to load ratio produced a coefficient of determination of 0.99949 with 70% of the data used for training and 30% for testing. The results can therefore be extended to other coastal Puerto Rican communities of varying sizes that have ratios within the ranges analysed in this study. This can empower decision makers to rapidly analyse designs that have availabilities well below 100%.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43926115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.1080/23744731.2023.2247938
Christian Rosdahl, B. Bernhardsson, Bryan A. Eisenhower
The performance of HVAC equipment, including chillers, is continuing to be pushed to theoretical limits, which impacts the necessity for advanced control logic to operate them efficiently and robustly. At the same time, their architectures are becoming more complex; many systems have multiple compressors, expansion devices, evaporators, circuits, or other elements that challenge control design and resulting performance. In order to maintain respectful controlled speed of response, stability, and robustness, controllers are becoming more complex, including the move from thermostatic control, to proportional integrator (PI), and to multiple-input multiple-output (MIMO) controllers. Model-based control design works well for their synthesis, while having accurate models for numerous product variants is unrealistic, often leading to very conservative designs. To address this, we propose and demonstrate a learning-based control tuner that supports the design of MIMO decoupling PI controllers using online information to adapt controller coefficients from an initial guess during commissioning or operation. The approach is tested on a physics-based model of a water-cooled screw chiller. The method is able to find a controller that performs better than a nominal controller (two single PI controllers) in terms of decreasing deviations from the operating point during disturbances while still following reference changes.
{"title":"Model-Free MIMO Control Tuning of a Chiller Process Using Reinforcement Learning","authors":"Christian Rosdahl, B. Bernhardsson, Bryan A. Eisenhower","doi":"10.1080/23744731.2023.2247938","DOIUrl":"https://doi.org/10.1080/23744731.2023.2247938","url":null,"abstract":"The performance of HVAC equipment, including chillers, is continuing to be pushed to theoretical limits, which impacts the necessity for advanced control logic to operate them efficiently and robustly. At the same time, their architectures are becoming more complex; many systems have multiple compressors, expansion devices, evaporators, circuits, or other elements that challenge control design and resulting performance. In order to maintain respectful controlled speed of response, stability, and robustness, controllers are becoming more complex, including the move from thermostatic control, to proportional integrator (PI), and to multiple-input multiple-output (MIMO) controllers. Model-based control design works well for their synthesis, while having accurate models for numerous product variants is unrealistic, often leading to very conservative designs. To address this, we propose and demonstrate a learning-based control tuner that supports the design of MIMO decoupling PI controllers using online information to adapt controller coefficients from an initial guess during commissioning or operation. The approach is tested on a physics-based model of a water-cooled screw chiller. The method is able to find a controller that performs better than a nominal controller (two single PI controllers) in terms of decreasing deviations from the operating point during disturbances while still following reference changes.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45019010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-29DOI: 10.1080/23744731.2023.2253085
S. Kujak, Morgan Leehey
This paper examines the findings of highly accelerated life tests (HALT), conducted according to ASHRAE Standard 97 sealed glass tube methodology for R-123 like, R-134a like and R-410A/R-404A like lower global warming potential (GWP) alternatives. Additionally, possible chemical breakdown pathways are reviewed for the new haloolefin refrigerants. Note, compositions for the following blends are shown as percent by weight. For R-123 like refrigerants, R-1336mzz(Z), R-1336mzz(E), R-514A (74.7% R-1336mzz(Z)/25.3% R-1130(E)), R-1233zd(E), and R-1224yd(Z) were examined with and without lubricants. R-1233zd(E) and R-1224yd(Z) were evaluated with mineral oil and the rest were evaluated with polyalkylene glycol (PAG), polyolester (POE) and polyvinyl ether (PVE) lubricants. For R-134a like refrigerants, R-1234ze(E), R-450A (42% R-134a/58% R-1234ze(E)), R-515B (91.1% R-1234ze(E)/8.9% R-227ea), R-1234yf, R-513A (56% R-1234yf/44% R-134a), and R-516A (77.5% R-1234yf/8.5% R-134a/14.0% R-152a) were examined with and without PAG, POE, and PVE lubricants. For R-410A/R-404A like, R-454B (68.9% R-32/31.1% R-1234yf), R-454C (21.5% R-32/78.5% R-1234yf), R-455A (3.0% R-744/21.5% R-32/75.5% R-1234yf), and R-468A (3.5% R-1132a/21.5% R-32/75.0% R-1234yf) were also examined with PAG, POE and PVE lubricants. R-466A (49% R-32/11.5% R-125/39.5% CF3I) was part of this study but will not be covered since it does not contain a haloolefin component.
{"title":"Chemical Stability Investigation of Haloolefin Refrigerants and Their Blends with Lubricants","authors":"S. Kujak, Morgan Leehey","doi":"10.1080/23744731.2023.2253085","DOIUrl":"https://doi.org/10.1080/23744731.2023.2253085","url":null,"abstract":"This paper examines the findings of highly accelerated life tests (HALT), conducted according to ASHRAE Standard 97 sealed glass tube methodology for R-123 like, R-134a like and R-410A/R-404A like lower global warming potential (GWP) alternatives. Additionally, possible chemical breakdown pathways are reviewed for the new haloolefin refrigerants. Note, compositions for the following blends are shown as percent by weight. For R-123 like refrigerants, R-1336mzz(Z), R-1336mzz(E), R-514A (74.7% R-1336mzz(Z)/25.3% R-1130(E)), R-1233zd(E), and R-1224yd(Z) were examined with and without lubricants. R-1233zd(E) and R-1224yd(Z) were evaluated with mineral oil and the rest were evaluated with polyalkylene glycol (PAG), polyolester (POE) and polyvinyl ether (PVE) lubricants. For R-134a like refrigerants, R-1234ze(E), R-450A (42% R-134a/58% R-1234ze(E)), R-515B (91.1% R-1234ze(E)/8.9% R-227ea), R-1234yf, R-513A (56% R-1234yf/44% R-134a), and R-516A (77.5% R-1234yf/8.5% R-134a/14.0% R-152a) were examined with and without PAG, POE, and PVE lubricants. For R-410A/R-404A like, R-454B (68.9% R-32/31.1% R-1234yf), R-454C (21.5% R-32/78.5% R-1234yf), R-455A (3.0% R-744/21.5% R-32/75.5% R-1234yf), and R-468A (3.5% R-1132a/21.5% R-32/75.0% R-1234yf) were also examined with PAG, POE and PVE lubricants. R-466A (49% R-32/11.5% R-125/39.5% CF3I) was part of this study but will not be covered since it does not contain a haloolefin component.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43631629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-29DOI: 10.1080/23744731.2023.2253089
Mahsa Salimi, L. De Nardo, V. Carvelli
Thermal energy storage (TES) based on phase change materials (PCM) is an effective strategy to reduce energy consumption in buildings. The efficient implementation of TES in building through PCMs, requires modification of their thermal performance, appropriate design and evaluation of their thermal and economic efficiency. One major challenge in the application of PCMs is the selection of high-performance and environmental-friendly supporting materials to overcome the most critical drawback of PCMs (solid-to-liquid transition and resulting leakage). This review focuses on expanded clay (EC) lightweight aggregate (LWA), as one of the promising supporting materials for development of form-stabilized PCM (FSPCM) in the lightweight concrete (LWC) industry. The large specific surface area and porous structure of expanded clay can maintain considerable amount of PCM. In addition, mechanical properties and compatibility with various PCMs make EC a suitable carrier. A detailed review of available researches is presented to elucidate the properties of PCMs embedded in EC for thermally efficient cement-based concrete. Various combinations of EC with the most used PCMs, thermal and mechanical properties of matrices containing PCM-EC, strategies to improve the efficiency of PCM performance, and finally the impact of PCM-EC based concretes on the thermal comfort of buildings are critically summarized.
{"title":"Phase change materials embedded in expanded clay aggregates to develop energy storage concrete: a review","authors":"Mahsa Salimi, L. De Nardo, V. Carvelli","doi":"10.1080/23744731.2023.2253089","DOIUrl":"https://doi.org/10.1080/23744731.2023.2253089","url":null,"abstract":"Thermal energy storage (TES) based on phase change materials (PCM) is an effective strategy to reduce energy consumption in buildings. The efficient implementation of TES in building through PCMs, requires modification of their thermal performance, appropriate design and evaluation of their thermal and economic efficiency. One major challenge in the application of PCMs is the selection of high-performance and environmental-friendly supporting materials to overcome the most critical drawback of PCMs (solid-to-liquid transition and resulting leakage). This review focuses on expanded clay (EC) lightweight aggregate (LWA), as one of the promising supporting materials for development of form-stabilized PCM (FSPCM) in the lightweight concrete (LWC) industry. The large specific surface area and porous structure of expanded clay can maintain considerable amount of PCM. In addition, mechanical properties and compatibility with various PCMs make EC a suitable carrier. A detailed review of available researches is presented to elucidate the properties of PCMs embedded in EC for thermally efficient cement-based concrete. Various combinations of EC with the most used PCMs, thermal and mechanical properties of matrices containing PCM-EC, strategies to improve the efficiency of PCM performance, and finally the impact of PCM-EC based concretes on the thermal comfort of buildings are critically summarized.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46133587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractElastocaloric cooling has no environmental effects during operation, and achieving a compact structure especially the driver is significant for its commercialization. In this article, a compact, standalone crankshaft driven single long NiTi tube compressive elastocaloric cooler is developed. A crankshaft driver was designed and fabricated to drive a compressive elastocaloric regenerator utilizing a single long polycrystalline superelastic NiTi shape memory alloy tube (outer diameter 5 mm, wall thickness 1 mm, and initial length 305 mm). A novel design of ceramic heat insulation plate was applied to the cooler to reduce the conduction heat loss from the NiTi tube to the stainless-steel loading heads. The cooling performance of the cooler was characterized using synchronized thermocouples and infrared thermography, and the specific cooling(heating) power, temperature span, and coefficient of performance of up to 65(125) W·kg−1, 9.1 K, and 5.0, respectively were measured. The progressions of the temperature span, specific cooling(heating) power, and coefficient of performance with the operation cycle and temperature lift were analyzed. An energy analysis revealed that the heat transfer fluid carried out only 14% of the latent heat generated by the NiTi tube, which demonstrated a potential to enhance the cooling performance by the improvement in the regenerator structure. AcknowledgementsWe thank Mr. Yuchen Zhang, Mr. Jiachen Lei, Mr. Junxian Ye, and Mr. William Chi Chung Wong in the Hong Kong University of Science and Technology for the beneficial discussions and construction of the crankshaft driver in the single long NiTi tube compressive elastocaloric cooler.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the National Natural Science Foundation of China (Grant No. 52206224), the Natural Science Research Start-up Foundation of Recruiting Talents of Hebei University of Science and Technology, the Chinese National Training Program of Innovation and Entrepreneurship for Undergraduates (Grant No. 202310082008), and the IER Foundation 2020 (Grant No. IERF202003).Notes on contributorsSiyuan ChengSiyuan Cheng, PhD, is an Assistant Professor. Zhengyu Li, BS, is a PhD Candidate. Weng Zak Lee, is an Undergraduate Student. Shuoyang Liu, is an Undergraduate Student. Yang Fu, is an Undergraduate Student. Yatao Zhao, is an Undergraduate Student. Mengyi Zhang, is an Undergraduate Student.
{"title":"Development of a crankshaft driven single long NiTi tube compressive elastocaloric cooler","authors":"Siyuan Cheng, Zhengyu Li, Weng Zak Lee, Shuoyang Liu, Yang Fu, Yatao Zhao, Mengyi Zhang","doi":"10.1080/23744731.2023.2242756","DOIUrl":"https://doi.org/10.1080/23744731.2023.2242756","url":null,"abstract":"AbstractElastocaloric cooling has no environmental effects during operation, and achieving a compact structure especially the driver is significant for its commercialization. In this article, a compact, standalone crankshaft driven single long NiTi tube compressive elastocaloric cooler is developed. A crankshaft driver was designed and fabricated to drive a compressive elastocaloric regenerator utilizing a single long polycrystalline superelastic NiTi shape memory alloy tube (outer diameter 5 mm, wall thickness 1 mm, and initial length 305 mm). A novel design of ceramic heat insulation plate was applied to the cooler to reduce the conduction heat loss from the NiTi tube to the stainless-steel loading heads. The cooling performance of the cooler was characterized using synchronized thermocouples and infrared thermography, and the specific cooling(heating) power, temperature span, and coefficient of performance of up to 65(125) W·kg−1, 9.1 K, and 5.0, respectively were measured. The progressions of the temperature span, specific cooling(heating) power, and coefficient of performance with the operation cycle and temperature lift were analyzed. An energy analysis revealed that the heat transfer fluid carried out only 14% of the latent heat generated by the NiTi tube, which demonstrated a potential to enhance the cooling performance by the improvement in the regenerator structure. AcknowledgementsWe thank Mr. Yuchen Zhang, Mr. Jiachen Lei, Mr. Junxian Ye, and Mr. William Chi Chung Wong in the Hong Kong University of Science and Technology for the beneficial discussions and construction of the crankshaft driver in the single long NiTi tube compressive elastocaloric cooler.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the National Natural Science Foundation of China (Grant No. 52206224), the Natural Science Research Start-up Foundation of Recruiting Talents of Hebei University of Science and Technology, the Chinese National Training Program of Innovation and Entrepreneurship for Undergraduates (Grant No. 202310082008), and the IER Foundation 2020 (Grant No. IERF202003).Notes on contributorsSiyuan ChengSiyuan Cheng, PhD, is an Assistant Professor. Zhengyu Li, BS, is a PhD Candidate. Weng Zak Lee, is an Undergraduate Student. Shuoyang Liu, is an Undergraduate Student. Yang Fu, is an Undergraduate Student. Yatao Zhao, is an Undergraduate Student. Mengyi Zhang, is an Undergraduate Student.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134983649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-09DOI: 10.1080/23744731.2023.2247948
M. Van Hove, J. Borrajo Bastero, M. Delghust, J. Laverge
Combined building indoor climate and energy simulation models only recently gained vast popularity and their application has been moving from the research community to a broader audience. Yet, in-situ empirical validation of this new generation of complex multi-purpose dynamic simulation models has lagged behind. Using a dynamic multizone building indoor climate and energy simulation model in Modelica with the IDEAS library and buoyancy driven airflow components (validated with CONTAM), this research presents model validation results and lessons learned from an in-situ empirical validation study of common indoor climate parameters (i.e., indoor air temperature ( ), relative humidity (RH) and CO2 concentration (CO2)) for an inhabited and mechanically ventilated case study dwelling in The Netherlands. The simulation results show that the latest generation of building indoor climate and energy models in Modelica have great ability to accurately predict common indoor climate parameters in multizone inhabited dwellings (provided that user behavior info is available). Evaluation metrics for the three studied parameters show excellent calibration criteria (i.e., MAE between 0.60–0.78 °C ( ), 3.5–4.6% (RH) and 88–181 ppm (CO2)) and the accompanying graphs corroborate the findings. In the event that no motion sensor data is available, statistically generated occupancy profiles prove good representative alternatives on the condition that basic info is available about the number of inhabitants and the inhabitants’ lifestyle. In-situ monitoring for empirical model validation proves to be a real challenge full of (un)foreseen obstacles.
{"title":"In-situ empirical validation of common indoor climate parameters in an inhabited multizone dwelling","authors":"M. Van Hove, J. Borrajo Bastero, M. Delghust, J. Laverge","doi":"10.1080/23744731.2023.2247948","DOIUrl":"https://doi.org/10.1080/23744731.2023.2247948","url":null,"abstract":"Combined building indoor climate and energy simulation models only recently gained vast popularity and their application has been moving from the research community to a broader audience. Yet, in-situ empirical validation of this new generation of complex multi-purpose dynamic simulation models has lagged behind. Using a dynamic multizone building indoor climate and energy simulation model in Modelica with the IDEAS library and buoyancy driven airflow components (validated with CONTAM), this research presents model validation results and lessons learned from an in-situ empirical validation study of common indoor climate parameters (i.e., indoor air temperature ( ), relative humidity (RH) and CO2 concentration (CO2)) for an inhabited and mechanically ventilated case study dwelling in The Netherlands. The simulation results show that the latest generation of building indoor climate and energy models in Modelica have great ability to accurately predict common indoor climate parameters in multizone inhabited dwellings (provided that user behavior info is available). Evaluation metrics for the three studied parameters show excellent calibration criteria (i.e., MAE between 0.60–0.78 °C ( ), 3.5–4.6% (RH) and 88–181 ppm (CO2)) and the accompanying graphs corroborate the findings. In the event that no motion sensor data is available, statistically generated occupancy profiles prove good representative alternatives on the condition that basic info is available about the number of inhabitants and the inhabitants’ lifestyle. In-situ monitoring for empirical model validation proves to be a real challenge full of (un)foreseen obstacles.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47691034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-09DOI: 10.1080/23744731.2023.2254102
Chandra Sekhar, William Bahnfleth
{"title":"IAQ 2020: Indoor environmental quality performance approaches transitioning from IAQ to IEQ, part 2 May 4–6, 2022 | Athens, Greece","authors":"Chandra Sekhar, William Bahnfleth","doi":"10.1080/23744731.2023.2254102","DOIUrl":"https://doi.org/10.1080/23744731.2023.2254102","url":null,"abstract":"","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135747018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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