Pub Date : 2023-07-10DOI: 10.1080/23744731.2023.2234231
K. Ejenakevwe, Junke Wang, Yilin Jiang, Li Song, Kini Roshan
While automated fault detection and diagnosis (AFDD) in residential heating, ventilation, and air-conditioning (HVAC) using smart thermostat data is gaining increasing attention in recent times, it still requires in-depth investigation for market adoption, especially with real-life data. This paper proposes an Internet of Things (IoT) - based approach that adds a smart sensor to the smart thermostat data to carry out AFDD. The approach uses a model which predicts enthalpy change across the evaporator and compares the prediction to the measured enthalpy change. Deviations which exceed analytically determined thresholds then signal faults in the HVAC system. The faults detected are either installation related or degradation related. Experimental tests were carried out in four homes located in Norman, Oklahoma. From the tests, installation issues like indoor/outdoor mismatch were detected in two homes, while a 30% low charge and low indoor airflow rate were detected in one home. The results show that the proposed AFDD algorithm was able to successfully detect two prevalent faults, namely low indoor airflow and low refrigerant charge. Unlike most of the smart thermostat-based approaches, the proposed IoT-based approach can detect and diagnose both faults but only require one additional sensor which is provided by smart thermostat manufacturers.
{"title":"Automated Fault Detection and Diagnosis of Airflow and Refrigerant Charge Faults in Residential HVAC systems using IoT-Enabled Measurements","authors":"K. Ejenakevwe, Junke Wang, Yilin Jiang, Li Song, Kini Roshan","doi":"10.1080/23744731.2023.2234231","DOIUrl":"https://doi.org/10.1080/23744731.2023.2234231","url":null,"abstract":"While automated fault detection and diagnosis (AFDD) in residential heating, ventilation, and air-conditioning (HVAC) using smart thermostat data is gaining increasing attention in recent times, it still requires in-depth investigation for market adoption, especially with real-life data. This paper proposes an Internet of Things (IoT) - based approach that adds a smart sensor to the smart thermostat data to carry out AFDD. The approach uses a model which predicts enthalpy change across the evaporator and compares the prediction to the measured enthalpy change. Deviations which exceed analytically determined thresholds then signal faults in the HVAC system. The faults detected are either installation related or degradation related. Experimental tests were carried out in four homes located in Norman, Oklahoma. From the tests, installation issues like indoor/outdoor mismatch were detected in two homes, while a 30% low charge and low indoor airflow rate were detected in one home. The results show that the proposed AFDD algorithm was able to successfully detect two prevalent faults, namely low indoor airflow and low refrigerant charge. Unlike most of the smart thermostat-based approaches, the proposed IoT-based approach can detect and diagnose both faults but only require one additional sensor which is provided by smart thermostat manufacturers.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49389813","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}
Local exhaust systems based on range hoods are widely used to reduce cooking oil fumes (COF) of kitchen spaces. This work proposes a range-hood-integrated air cleaner to improve air distribution in residential kitchens and reduce individual inhalation exposure to COF. Effects of hood exhaust rates, cooking–heating intensities, and airflow parameters of the air cleaner on the volume-averaged concentration (VAC) of kitchen space and the intake fraction (IF) are discussed through orthogonal experimental design, and significant factors are the hood exhaust rate, the air supply velocity, and angle of the air cleaner by evaluating significance levels. Optimal airflow parameters of the air cleaner are obtained through single-factor analysis, and VAC is reduced by approximately 90% compared with the single range-hood exhaust system. The energy-saving potential of the air cleaner is identified and evaluated using the concept of the equivalent exhaust rate. The air cleaner is more conducive to creating a comfortable kitchen environment and reducing heat transfer load. This work provides a new solution for optimizing air distribution in highly polluted kitchen environments.
{"title":"Indoor air quality and energy-saving potential improvement of a range-hood-integrated air cleaner","authors":"Yumei Hou, Yukun Xu, Zhi Liu, Ziyin Lin, Wuhao Xie, Changsheng Cao, Zhiwei Zheng, Jun Gao","doi":"10.1080/23744731.2023.2234238","DOIUrl":"https://doi.org/10.1080/23744731.2023.2234238","url":null,"abstract":"Local exhaust systems based on range hoods are widely used to reduce cooking oil fumes (COF) of kitchen spaces. This work proposes a range-hood-integrated air cleaner to improve air distribution in residential kitchens and reduce individual inhalation exposure to COF. Effects of hood exhaust rates, cooking–heating intensities, and airflow parameters of the air cleaner on the volume-averaged concentration (VAC) of kitchen space and the intake fraction (IF) are discussed through orthogonal experimental design, and significant factors are the hood exhaust rate, the air supply velocity, and angle of the air cleaner by evaluating significance levels. Optimal airflow parameters of the air cleaner are obtained through single-factor analysis, and VAC is reduced by approximately 90% compared with the single range-hood exhaust system. The energy-saving potential of the air cleaner is identified and evaluated using the concept of the equivalent exhaust rate. The air cleaner is more conducive to creating a comfortable kitchen environment and reducing heat transfer load. This work provides a new solution for optimizing air distribution in highly polluted kitchen environments.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47020898","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 : 2023-07-10DOI: 10.1080/23744731.2023.2234226
Sarah Mollier, Charles-Antoine Deslauriers, J. Tamasauskas, Solange Prud’homme, M. Kegel
Heat pumps offer an efficient electrification of space heating but can significantly vary the magnitude and duration of house-level electrical demand, especially when replacing fuel-fired heating systems. This paper uses a simulation-based approach to simulate the electrical demand variations of air-source heat pumps (ASHPs) in six Canadian cities (Halifax, Montreal, Toronto, Winnipeg, Vancouver, Whitehorse) when replacing natural gas or electric baseboard heating. Detailed housing models (including a highly zoned model capturing room-based baseboard controls) are combined with a series of custom non-HVAC load profiles and an enhanced data-driven ASHP model to assess the variation that occupancy, climate, and type of heat pump integration can have on electrical demand. ASHPs are shown to increase the magnitude and duration of electrical demand when replacing natural gas furnaces, although selection of climate-appropriate systems (e.g. cold climate units in colder climates) may reduce the magnitude and coincidence of this demand. Where heat pumps replace electric baseboards, HVAC demand may decrease by up to 3.4 kW during ASHP operating periods and remain equal when the ambient temperatures are below the ASHP cutoff. A study of simple mitigation measures through varying temperature setpoints demonstrates the ability of proper controls to reduce electrical demand during high-demand periods.
{"title":"Simulating the Electrical Demand Variations of Air-Source Heat Pumps in Canadian Single-Family Housing","authors":"Sarah Mollier, Charles-Antoine Deslauriers, J. Tamasauskas, Solange Prud’homme, M. Kegel","doi":"10.1080/23744731.2023.2234226","DOIUrl":"https://doi.org/10.1080/23744731.2023.2234226","url":null,"abstract":"Heat pumps offer an efficient electrification of space heating but can significantly vary the magnitude and duration of house-level electrical demand, especially when replacing fuel-fired heating systems. This paper uses a simulation-based approach to simulate the electrical demand variations of air-source heat pumps (ASHPs) in six Canadian cities (Halifax, Montreal, Toronto, Winnipeg, Vancouver, Whitehorse) when replacing natural gas or electric baseboard heating. Detailed housing models (including a highly zoned model capturing room-based baseboard controls) are combined with a series of custom non-HVAC load profiles and an enhanced data-driven ASHP model to assess the variation that occupancy, climate, and type of heat pump integration can have on electrical demand. ASHPs are shown to increase the magnitude and duration of electrical demand when replacing natural gas furnaces, although selection of climate-appropriate systems (e.g. cold climate units in colder climates) may reduce the magnitude and coincidence of this demand. Where heat pumps replace electric baseboards, HVAC demand may decrease by up to 3.4 kW during ASHP operating periods and remain equal when the ambient temperatures are below the ASHP cutoff. A study of simple mitigation measures through varying temperature setpoints demonstrates the ability of proper controls to reduce electrical demand during high-demand periods.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48466922","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}
Managers of small commercial building (SCB) portfolios need to understand occupant interactions with heating, ventilation, and air-conditioning (HVAC) systems to reduce energy use and greenhouse gas (GHG) emissions. In Canada, SCBs are currently underserved by energy conservation and thermal analysis tools because of their dispersion and lower payback potential. However, the emergence of smart thermostats (STs) and their central data collection platform provide a cost-effective solution to gather data from portfolios of SCBs and improve our understanding of occupant-HVAC interactions. This article analyzes the relationship between HVAC schedules (temperature set-points), indoor thermal conditions (dry-bulb temperature and relative humidity), and occupant behavior (thermostat overrides) in a portfolio of 30 SCBs in Ontario, Canada. The results reveal that temperature set-points were not properly selected in the portfolio of SCBs, leading to a large range of indoor thermal conditions and increased thermostat overrides. Specifically, the study demonstrates that building- and zone-specific HVAC schedules are necessary to minimize discomfort and reduce energy consumption in the portfolio of SCBs. The findings of this study can provide valuable insights for portfolio managers to improve HVAC schedules in a manner that reduces energy consumption and GHG emissions while accommodating occupants’ thermal comfort and productivity.
{"title":"Using smart thermostat override data to provide insights for improving heating, ventilation, and air-conditioning system scheduling in a portfolio of small commercial buildings","authors":"Farid Bahiraei, Justin Berquist, Saptak Dutta, Brent Huchuk","doi":"10.1080/23744731.2023.2234241","DOIUrl":"https://doi.org/10.1080/23744731.2023.2234241","url":null,"abstract":"Managers of small commercial building (SCB) portfolios need to understand occupant interactions with heating, ventilation, and air-conditioning (HVAC) systems to reduce energy use and greenhouse gas (GHG) emissions. In Canada, SCBs are currently underserved by energy conservation and thermal analysis tools because of their dispersion and lower payback potential. However, the emergence of smart thermostats (STs) and their central data collection platform provide a cost-effective solution to gather data from portfolios of SCBs and improve our understanding of occupant-HVAC interactions. This article analyzes the relationship between HVAC schedules (temperature set-points), indoor thermal conditions (dry-bulb temperature and relative humidity), and occupant behavior (thermostat overrides) in a portfolio of 30 SCBs in Ontario, Canada. The results reveal that temperature set-points were not properly selected in the portfolio of SCBs, leading to a large range of indoor thermal conditions and increased thermostat overrides. Specifically, the study demonstrates that building- and zone-specific HVAC schedules are necessary to minimize discomfort and reduce energy consumption in the portfolio of SCBs. The findings of this study can provide valuable insights for portfolio managers to improve HVAC schedules in a manner that reduces energy consumption and GHG emissions while accommodating occupants’ thermal comfort and productivity.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":"1 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42272092","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 : 2023-07-10DOI: 10.1080/23744731.2023.2234250
Amin Sepehri, G. Pavlak
Active insulation systems (AIS) have been conceptualized to make buildings more responsive to changing environmental conditions, creating energy efficiency and flexibility gains. Building flexibility and efficiency can be further improved if the building is also equipped with optimized HVAC system controls. Optimal control of AIS and HVAC systems can be used to activate thermal mass, and past work has quantified the potential benefits of jointly optimizing both systems. In this work, we more fully elucidate and evaluate the potential tradeoffs between optimal control of these technologies with respect to building energy use and peak demand–including different configurations of heat pump systems and integrated building thermal energy storage. Tradeoffs are revealed by applying a multi-objective optimal control framework and comparing the Pareto optimal sets across various system configurations. Discussion of the results provides insights into how buildings can be best designed and controlled to achieve both energy efficiency and flexibility.
{"title":"Trade-offs in Optimization of Active Insulation Systems and HVAC: A Case Study in Residential Buildings","authors":"Amin Sepehri, G. Pavlak","doi":"10.1080/23744731.2023.2234250","DOIUrl":"https://doi.org/10.1080/23744731.2023.2234250","url":null,"abstract":"Active insulation systems (AIS) have been conceptualized to make buildings more responsive to changing environmental conditions, creating energy efficiency and flexibility gains. Building flexibility and efficiency can be further improved if the building is also equipped with optimized HVAC system controls. Optimal control of AIS and HVAC systems can be used to activate thermal mass, and past work has quantified the potential benefits of jointly optimizing both systems. In this work, we more fully elucidate and evaluate the potential tradeoffs between optimal control of these technologies with respect to building energy use and peak demand–including different configurations of heat pump systems and integrated building thermal energy storage. Tradeoffs are revealed by applying a multi-objective optimal control framework and comparing the Pareto optimal sets across various system configurations. Discussion of the results provides insights into how buildings can be best designed and controlled to achieve both energy efficiency and flexibility.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":" ","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48066892","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 : 2023-07-03DOI: 10.1080/23744731.2023.2234249
J. P. Bijarniya, J. Sarkar, Shivam Tiwari, P. Maiti, Candidate. Jahar Sarkar, PhD Candidate. P. Maiti
The daytime radiative cooling technology may be effectively used to passively cool the water and hence mitigate the undesirable solar water heating of the roof-top storage tank in the summer. Hence, this work presents the radiative water cooler design, development and experimental and numerical performance characteristics. Radiative water cooler surface coating has been developed using the polymer (PMMA)-particle (barium sulfate) composite structure. The effects of various water inlet temperatures and volume flow rates on the water temperature drop and cooling capacity are experimentally and numerically performed. Sub-ambient water cooling throughout the day is observed for a range of 0.1–0.4 L/min water flow rates at the near-ambient inlet temperature conditions. The maximum sub-ambient water temperature drop of 6.1 °C (that of 3.5 °C at noon) is observed with a developed radiative cooler for the flow rate of 0.1 l/min. The usage of the daytime radiative water cooler for sub-ambient water temperature drop is found to be more suitable for above-ambient water inlet temperature. Apart from the solar irradiance, ambient temperature, ambient humidity, wind velocity and coating surface emissivity characteristics, cooling capacity and surface temperature distribution of radiative water cooler also depend on the water inlet conditions.
{"title":"Development and experimental performance characteristics of composite coated daytime radiative water cooler","authors":"J. P. Bijarniya, J. Sarkar, Shivam Tiwari, P. Maiti, Candidate. Jahar Sarkar, PhD Candidate. P. Maiti","doi":"10.1080/23744731.2023.2234249","DOIUrl":"https://doi.org/10.1080/23744731.2023.2234249","url":null,"abstract":"The daytime radiative cooling technology may be effectively used to passively cool the water and hence mitigate the undesirable solar water heating of the roof-top storage tank in the summer. Hence, this work presents the radiative water cooler design, development and experimental and numerical performance characteristics. Radiative water cooler surface coating has been developed using the polymer (PMMA)-particle (barium sulfate) composite structure. The effects of various water inlet temperatures and volume flow rates on the water temperature drop and cooling capacity are experimentally and numerically performed. Sub-ambient water cooling throughout the day is observed for a range of 0.1–0.4 L/min water flow rates at the near-ambient inlet temperature conditions. The maximum sub-ambient water temperature drop of 6.1 °C (that of 3.5 °C at noon) is observed with a developed radiative cooler for the flow rate of 0.1 l/min. The usage of the daytime radiative water cooler for sub-ambient water temperature drop is found to be more suitable for above-ambient water inlet temperature. Apart from the solar irradiance, ambient temperature, ambient humidity, wind velocity and coating surface emissivity characteristics, cooling capacity and surface temperature distribution of radiative water cooler also depend on the water inlet conditions.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":"29 1","pages":"606 - 617"},"PeriodicalIF":1.9,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41477649","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 : 2023-06-21DOI: 10.1080/23744731.2023.2222622
Saleh S. Meibodi, S. Rees
The transient behavior of buried pipe systems plays a significant role in many heating and cooling systems, particularly in thermal energy networks and ground heat exchangers. In this study, the dynamic thermal network (DTN) approach’s validity as a response factor method in modeling dynamic conduction heat transfer in a buried pipe system is experimentally validated. A lab-scale representation of a buried pipe system has been excited by step changes in boundary temperatures and heat fluxes measured up to times approaching steady-state conditions. This data is used to derive weighting factors and also evaluate the validity of numerical representations of the buried pipe and to verify that the DTN method can reproduce the heat flux responses. It is demonstrated that the weighting factors required in this method can be derived from both numerical and experimental step-response time series data. The DTN method is found to be both accurate in reproducing the heat fluxes in the validation experiments but also significantly more computationally efficient than a conventional numerical model when simulating long timescale responses in buried pipe systems.
{"title":"Experimental validation of the dynamic thermal network approach in modeling buried pipes","authors":"Saleh S. Meibodi, S. Rees","doi":"10.1080/23744731.2023.2222622","DOIUrl":"https://doi.org/10.1080/23744731.2023.2222622","url":null,"abstract":"The transient behavior of buried pipe systems plays a significant role in many heating and cooling systems, particularly in thermal energy networks and ground heat exchangers. In this study, the dynamic thermal network (DTN) approach’s validity as a response factor method in modeling dynamic conduction heat transfer in a buried pipe system is experimentally validated. A lab-scale representation of a buried pipe system has been excited by step changes in boundary temperatures and heat fluxes measured up to times approaching steady-state conditions. This data is used to derive weighting factors and also evaluate the validity of numerical representations of the buried pipe and to verify that the DTN method can reproduce the heat flux responses. It is demonstrated that the weighting factors required in this method can be derived from both numerical and experimental step-response time series data. The DTN method is found to be both accurate in reproducing the heat fluxes in the validation experiments but also significantly more computationally efficient than a conventional numerical model when simulating long timescale responses in buried pipe systems.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":"29 1","pages":"589 - 605"},"PeriodicalIF":1.9,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49137066","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 : 2023-06-08DOI: 10.1080/23744731.2023.2217729
Gabriel Dion, Philippe Pasquier, Denis Marcotte, Gabrielle Beaudry
Thermal response test interpretation methods usually rely on the assumptions of constant operating conditions in time. However, through desired or undesired processes, these conditions often vary in time. Since interpretation is usually done with stationary methods, no current algorithm allows to account for non-stationarity in thermal response test, as encountered with varying flow rate. The goal of this article is to apply a multi-deconvolution algorithm to retrieve a set of short-term transfer functions during a thermal response test with changing operating conditions. The deconvolution algorithm uses an optimization-based technique as the inverse model, while considering non-stationarity in the forward model through a recent non-stationary convolution algorithm. By optimizing a set of nodes on each estimated short-term transfer function, precise reconstruction of the experimental temperatures is possible. Results show that temperature reconstruction is as precise as an error of 0.06 °C on numerical cases and 0.07 °C on field cases. The usable transfer function duration and an analysis of the objective function’s optimum are also demonstrated. With the proposed algorithm, only the dataset of a thermal response test is needed to obtain short-term transfer functions when operating conditions are changing.
{"title":"Multi-deconvolution in non-stationary conditions applied to experimental thermal response test analysis to obtain short-term transfer functions","authors":"Gabriel Dion, Philippe Pasquier, Denis Marcotte, Gabrielle Beaudry","doi":"10.1080/23744731.2023.2217729","DOIUrl":"https://doi.org/10.1080/23744731.2023.2217729","url":null,"abstract":"Thermal response test interpretation methods usually rely on the assumptions of constant operating conditions in time. However, through desired or undesired processes, these conditions often vary in time. Since interpretation is usually done with stationary methods, no current algorithm allows to account for non-stationarity in thermal response test, as encountered with varying flow rate. The goal of this article is to apply a multi-deconvolution algorithm to retrieve a set of short-term transfer functions during a thermal response test with changing operating conditions. The deconvolution algorithm uses an optimization-based technique as the inverse model, while considering non-stationarity in the forward model through a recent non-stationary convolution algorithm. By optimizing a set of nodes on each estimated short-term transfer function, precise reconstruction of the experimental temperatures is possible. Results show that temperature reconstruction is as precise as an error of 0.06 °C on numerical cases and 0.07 °C on field cases. The usable transfer function duration and an analysis of the objective function’s optimum are also demonstrated. With the proposed algorithm, only the dataset of a thermal response test is needed to obtain short-term transfer functions when operating conditions are changing.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135215641","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 : 2023-05-09DOI: 10.1080/23744731.2023.2210976
Ting Cao, L. Lan, Z. Lian, Jingyun Shen
Light helps mankind synchronize the circadian rhythm, necessitating the need to create a luminous environment in a bedroom. Many studies have focused on the effect of bedroom lighting regulation on sleep. However, there was a lack of research on how psychology responses are connected to sleep in residential bedroom. Thus, this chamber-based study explored mood differences among three correlated color temperatures (CCT; 2700 K, 4100 K, 5500 K). Additionally, the study analyzed the correlation of pre- and post-sleep psychological states with sleep quality. The results showed that suitable artificial lights (CCT at 2700K) in a bedroom before and after sleep under different conditions would provide the relaxation for subjects. Moreover, SOL, SWS, and SE were significantly different across different CCTs. According to the correlation and regression analysis, there were four groups of Pearson significantly correlated variables with coefficients of determination ranging from 0.34 to 0.70. Among them, 67% of the variation in SOL could be explained by the degree of pre sleep relaxation and pleasure. Furthermore, abundant and healthy sleep might perpetuate the mood generated by artificial lights. Finally, the roles of psychological states and sleep physiological responses should be considered while creating comfortable lighting conditions in bedrooms.
{"title":"Associations between psychological responses under artificial light environment and sleep activity","authors":"Ting Cao, L. Lan, Z. Lian, Jingyun Shen","doi":"10.1080/23744731.2023.2210976","DOIUrl":"https://doi.org/10.1080/23744731.2023.2210976","url":null,"abstract":"Light helps mankind synchronize the circadian rhythm, necessitating the need to create a luminous environment in a bedroom. Many studies have focused on the effect of bedroom lighting regulation on sleep. However, there was a lack of research on how psychology responses are connected to sleep in residential bedroom. Thus, this chamber-based study explored mood differences among three correlated color temperatures (CCT; 2700 K, 4100 K, 5500 K). Additionally, the study analyzed the correlation of pre- and post-sleep psychological states with sleep quality. The results showed that suitable artificial lights (CCT at 2700K) in a bedroom before and after sleep under different conditions would provide the relaxation for subjects. Moreover, SOL, SWS, and SE were significantly different across different CCTs. According to the correlation and regression analysis, there were four groups of Pearson significantly correlated variables with coefficients of determination ranging from 0.34 to 0.70. Among them, 67% of the variation in SOL could be explained by the degree of pre sleep relaxation and pleasure. Furthermore, abundant and healthy sleep might perpetuate the mood generated by artificial lights. Finally, the roles of psychological states and sleep physiological responses should be considered while creating comfortable lighting conditions in bedrooms.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":"29 1","pages":"647 - 660"},"PeriodicalIF":1.9,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42622257","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 : 2023-04-20DOI: 10.1080/23744731.2023.2203044
F. Liu, Wenlian Ye, Yingwen Liu, Pengcheng Yang
This article focuses on evaluating and analyzing the performance of an autocascade refrigeration system with the zeotropic mixture of R600a/R1150/R14 refrigerants using grey correlation theory and response surface methodology (RSM). The correlation degree among various factors is analyzed using grey correlation theory. The interactive influences that have significant impacts on the six output parameters are illustrated, and a regression model is further validated by five confirmation parameters. The results show that the vapor quality of the evaporator outlet is the greatest factor that affecting the refrigerating capacity and coefficient of performance (COP). However, the evaporation temperature has the greatest effect on compressor’s discharge temperature, pressure ratio, exergy destruction rates, and exergy efficiency. Lower vapor quality of the condenser outlet and condensation temperature can improve the performances of refrigerating capacity, COP, compressor’s discharge temperature, compression ratio, total exergy destruction rate, and exergy efficiency based on the RSM results. The random five groups of validation parameters indicate that the errors between the predicted modeling and calculation results are all less than 5%, demonstrating that the RSM model has good predictability. The results achieved in this work will assist in the optimizing analysis and the application of cryogenic refrigerators.
{"title":"Performance evaluation of an auto-cascade refrigeration system using grey correlation theory and response surface methodology","authors":"F. Liu, Wenlian Ye, Yingwen Liu, Pengcheng Yang","doi":"10.1080/23744731.2023.2203044","DOIUrl":"https://doi.org/10.1080/23744731.2023.2203044","url":null,"abstract":"This article focuses on evaluating and analyzing the performance of an autocascade refrigeration system with the zeotropic mixture of R600a/R1150/R14 refrigerants using grey correlation theory and response surface methodology (RSM). The correlation degree among various factors is analyzed using grey correlation theory. The interactive influences that have significant impacts on the six output parameters are illustrated, and a regression model is further validated by five confirmation parameters. The results show that the vapor quality of the evaporator outlet is the greatest factor that affecting the refrigerating capacity and coefficient of performance (COP). However, the evaporation temperature has the greatest effect on compressor’s discharge temperature, pressure ratio, exergy destruction rates, and exergy efficiency. Lower vapor quality of the condenser outlet and condensation temperature can improve the performances of refrigerating capacity, COP, compressor’s discharge temperature, compression ratio, total exergy destruction rate, and exergy efficiency based on the RSM results. The random five groups of validation parameters indicate that the errors between the predicted modeling and calculation results are all less than 5%, demonstrating that the RSM model has good predictability. The results achieved in this work will assist in the optimizing analysis and the application of cryogenic refrigerators.","PeriodicalId":21556,"journal":{"name":"Science and Technology for the Built Environment","volume":"29 1","pages":"491 - 507"},"PeriodicalIF":1.9,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41840125","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：