An Adaptive Vent System for Localized and Customized Thermal Management in Buildings

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Cem Keskin ◽  
M. Pinar Mengüç
Keyword(s):  
Temperature Distribution ◽  
Thermal Management ◽  
System Modeling ◽  
Ventilation System ◽  
Control Unit ◽  
Thermal Conditions ◽  
User Preferences ◽  
User Engagement ◽  
Design Development ◽  
Modeling Methodology

Abstract This paper introduces an innovative ventilation system that is capable of providing localized and customized thermal conditions in buildings. The system has diffusers with individually operable flaps that facilitate asymmetric air inlet to control air flow inside a room in an effective way. Moreover, the system involves distributed temperature sensors, a user interface, and a control unit that allows creation and management of “thermal subzones” within a room in accordance with the different preferences of occupants. As a specific case, the thermal management of a typical office in an academic building is considered. Both experimental and numerical studies were conducted to show that it is possible to achieve several degrees of temperature differences at different room locations in a transient and controllable fashion. The dynamic management of the temperature distribution in a room can prevent the waste of conditioning energy. It is shown that the system provides a practical and impactful solution by adapting to different user preferences (UPs) and by minimizing the resource use. In order to deal with the complexity of design, development, and operation of the system, it is considered as a cyber-physical-social system (CPSS). The core of the CPSS approach used here is an enhanced hybrid system modeling methodology that couples human dimension with formal hybrid dynamical modeling. Based on a coherent conceptual framing, the approach can combine the three core aspects, like cyber infrastructure, physical dynamics, and social/human interactions of modern building energy systems to accommodate the environmental challenges. Besides physics-based achievements (managing temperature distribution inside a room), the new AVS can also leverage user engagement and behavior change for energy efficiency in buildings by facilitating a new practice for occupants' interaction with heating, ventilation, and air conditioning (HVAC) system.

scholarly journals An Investigation of the Effect of Ventilation Inlet and Outlet Arrangement on Heat Concentration in a Ship Engine Room

2017 ◽  
Vol 7 (5) ◽  
pp. 1996-2004
Author(s):  
E. Alizadeh ◽  
A. Maleki ◽  
Α. Mohamadi
Keyword(s):  
Temperature Distribution ◽  
Distribution Pattern ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Temperature Level ◽  
Average Temperature ◽  
Air Inlet ◽  
Engine Room ◽  
Air Volume ◽  
Main Engine

Τhe ventilation in the ship engine rooms is an essential issue concerning finest performance of engines and diesel generators as well as electric motors. The present study has aimed at the analysis of temperature distribution inside the ship main engine room. In the same way, attempts have been made to identify those points with considerable thermal concentration in main engine room space, so that proper ventilation systems could be engineered and utilized and favorable thermal conditions could be realized. The CFD approach has been utilized in order to analyze impact of the designed ventilation system on the temperature distribution pattern. The Inlet layout and area have been analyzed under a variety of scenarios in order to decrease the average temperature and eliminate the heat concentrations in various points of the engine room. The temperature distribution and location and area of ventilation air inlet have been studied in different modes resulted in temperature distribution pattern, heat concentration outline and average volumetric temperature level in each mode. The results indicated that considerable circulating air volume is required compared to those levels suggested by common practices, calculations and standards in order to eliminate the heat concentration.

Numerical and Experimental Modeling of Indoor Air Quality Inside a Conditioned Space with Mechanical Ventilation and DX-Air Conditioner

2020 ◽  
Vol 38 (9A) ◽  
pp. 1257-1275
Author(s):  
Wisam M. Mareed ◽  
Hasanen M. Hussen
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Airflow Rate ◽  
Air Conditioner ◽  
Breathing Zone ◽  
Lecture Room ◽  
Ventilation Performance

 Elevated CO2 rates in a building affect the health of the occupant. This paper deals with an experimental and numerical analysis conducted in a full-scale test room located in the Department of Mechanical Engineering at the University of Technology. The experiments and CFD were conducted for analyzing ventilation performance. It is a study on the effect of the discharge airflow rate of the ceiling type air-conditioner on ventilation performance in the lecture room with the mixing ventilation. Most obtained findings show that database and questionnaires analyzed prefer heights between 0.2 m to 1.2 m in the middle of an occupied zone and breathing zone height of between 0.75 m to 1.8 given in the literature surveyed. It is noticed the mismatch of internal conditions with thermal comfort, and indoor air quality recommended by [ASHRAE Standard 62, ANSI / ASHRAE Standard 55-2010]. CFD simulations have been carried to provide insights on the indoor air quality and comfort conditions throughout the classroom. Particle concentrations, thermal conditions, and modified ventilation system solutions are reported.

Critical review towards thermal management systems of lithium-ion batteries in electric vehicle with its electronic control unit and assessment tools

2021 ◽  
pp. 095440702098286
Author(s):  
C Kannan ◽  
R Vignesh ◽  
C Karthick ◽  
B Ashok
Keyword(s):  
Lithium Ion Batteries ◽  
Thermal Management ◽  
Electronic Control Unit ◽  
Lithium Ion ◽  
Control Unit ◽  
Assessment Tools ◽  
Electronic Control ◽  
Battery Thermal Management ◽  
Thermal Management System ◽  
Battery Thermal Management System

Lithium-ion batteries are facing difficulties in an aspect of protection towards battery thermal safety issues which leads to performance degradation or thermal runaway. To negate these issues an effective battery thermal management system is absolute pre-requisite to safeguard the lithium-ion batteries. In this context to support the future endeavours and to improvise battery thermal management system (BTMS) design and its operation the article reveals on three aspects through the analysis of scientific literatures. First, this paper collates the present research progress and status of various battery management strategies employed to lithium-ion batteries. Further, to promote stable and efficient BTMS operation as an initiation the extensive attention is paid towards roles of BTMS electronic control unit and also presented the essential functionality need to consider for designing best BTMS control strategy. Finally, elucidates the various unconventional assessment tools can be employed to recognize the suitable thermal management technique and also for establish optimum BTMS operation based on requirements. From the experience of this article additionally delivers some of the research gaps identified and the essential areas need to focus for the development of superior lithium-ion BTMS technology. All the contents reveal in this article will hopefully assist to the design commercially suitable effective BTMS technology especially for electro-mobility application.

scholarly journals Thermal Analysis of Cold Plate with Different Configurations for Thermal Management of a Lithium-Ion Battery

Batteries ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 17
Author(s):  
Seyed Saeed Madani ◽  
Erik Schaltz ◽  
Søren Knudsen Kær
Keyword(s):  
Thermal Analysis ◽  
Temperature Distribution ◽  
Lithium Ion Battery ◽  
Thermal Management ◽  
Electric Vehicles ◽  
Heat Dissipation ◽  
Lithium Ion ◽  
Cold Plate ◽  
Liquid Cooling ◽  
Cooling Design

Thermal analysis and thermal management of lithium-ion batteries for utilization in electric vehicles is vital. In order to investigate the thermal behavior of a lithium-ion battery, a liquid cooling design is demonstrated in this research. The influence of cooling direction and conduit distribution on the thermal performance of the lithium-ion battery is analyzed. The outcomes exhibit that the appropriate flow rate for heat dissipation is dependent on different configurations for cold plate. The acceptable heat dissipation condition could be acquired by adding more cooling conduits. Moreover, it was distinguished that satisfactory cooling direction could efficiently enhance the homogeneity of temperature distribution of the lithium-ion battery.

Analysis of Thermal Properties of Power Multifinger HEMT Devices

2018 ◽  
Author(s):  
Aleš Chvála ◽  
Robert Szobolovszký ◽  
Jaroslav Kováč ◽  
Martin Florovič ◽  
Juraj Marek ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Thermal Management ◽  
High Electron Mobility Transistor ◽  
Structure Design ◽  
High Electron ◽  
Design And Optimization ◽  
Chip Temperature ◽  
Materials Used ◽  
On Chip ◽  
Measurement Approach

In this paper, several methods suitable for real time on-chip temperature measurements of power AlGaN/GaN based high-electron mobility transistor (HEMT) grown on SiC substrate are presented. The measurement of temperature distribution on HEMT surface using Raman spectroscopy is presented. We have deployed a temperature measurement approach utilizing electrical I-V characteristics of the neighboring Schottky diode under different dissipated power of the transistor heat source. These methods are verified by measurements with micro thermistors. The results show that these methods have a potential for HEMT analysis in thermal management. The features and limitations of the proposed methods are discussed. The thermal parameters of materials used in the device are extracted from temperature distribution in the structure with the support of 3-D device thermal simulation. The thermal analysis of the multifinger power HEMT is performed. The effects of the structure design and fabrication processes from semiconductor layers, metallization, and packaging up to cooling solutions are investigated. The analysis of thermal behavior can help during design and optimization of power HEMT.

scholarly journals Adults’ Preferences for Behavior Change Techniques and Engagement Features in a Mobile App to Promote 24-Hour Movement Behaviors: Cross-Sectional Survey Study (Preprint)

2019 ◽  
Author(s):  
Ann DeSmet ◽  
Ilse De Bourdeaudhuij ◽  
Sebastien Chastin ◽  
Geert Crombez ◽  
Ralph Maddison ◽  
...  
Keyword(s):  
Behavior Change ◽  
Repeated Measures ◽  
Self Regulation ◽  
Mobile App ◽  
User Preferences ◽  
Movement Behavior ◽  
Survey Study ◽  
User Engagement ◽  
Behavior Change Techniques ◽  
Self Monitoring

BACKGROUND There is a limited understanding of components that should be included in digital interventions for 24-hour movement behaviors (physical activity [PA], sleep, and sedentary behavior [SB]). For intervention effectiveness, user engagement is important. This can be enhanced by a user-centered design to, for example, explore and integrate user preferences for intervention techniques and features. OBJECTIVE This study aimed to examine adult users’ preferences for techniques and features in mobile apps for 24-hour movement behaviors. METHODS A total of 86 participants (mean age 37.4 years [SD 9.2]; 49/86, 57% female) completed a Web-based survey. Behavior change techniques (BCTs) were based on a validated taxonomy v2 by Abraham and Michie, and engagement features were based on a list extracted from the literature. Behavioral data were collected using Fitbit trackers. Correlations, (repeated measures) analysis of variance, and independent sample <italic>t</italic> tests were used to examine associations and differences between and within users by the type of health domain and users’ behavioral intention and adoption. RESULTS Preferences were generally the highest for information on the health consequences of movement behavior self-monitoring, behavioral feedback, insight into healthy lifestyles, and tips and instructions. Although the same ranking was found for techniques across behaviors, preferences were stronger for all but one BCT for PA in comparison to the other two health behaviors. Although techniques fit user preferences for addressing PA well, supplemental techniques may be able to address preferences for sleep and SB in a better manner. In addition to what is commonly included in apps, sleep apps should consider providing tips for sleep. SB apps may wish to include more self-regulation and goal-setting techniques. Few differences were found by users’ intentions or adoption to change a particular behavior. Apps should provide more self-monitoring (<italic>P</italic>=.03), information on behavior health outcome (<italic>P</italic>=.048), and feedback (<italic>P</italic>=.04) and incorporate social support (<italic>P</italic>=.048) to help those who are further removed from healthy sleep. A virtual coach (<italic>P</italic><.001) and video modeling (<italic>P</italic>=.004) may provide appreciated support to those who are physically less active. PA self-monitoring appealed more to those with an intention to change PA (<italic>P</italic>=.03). Social comparison and support features are not high on users’ agenda and may not be needed from an engagement point of view. Engagement features may not be very relevant for user engagement but should be examined in future research with a less reflective method. CONCLUSIONS The findings of this study provide guidance for the design of digital 24-hour movement behavior interventions. As 24-hour movement guidelines are increasingly being adopted in several countries, our study findings are timely to support the design of interventions to meet these guidelines.

scholarly journals Thermal management evaluation of the complex electro-optical system

2017 ◽  
Vol 21 (5) ◽  
pp. 2189-2196
Author(s):  
Srecko Nijemcevic ◽  
Milan Tasic ◽  
Branko Livada ◽  
Dragana Peric ◽  
Marko Tasic
Keyword(s):  
Temperature Distribution ◽  
Thermal Management ◽  
Optical System ◽  
Life Time ◽  
System Optimization ◽  
Working Environment ◽  
Outdoor Environment ◽  
System Component ◽  
Catastrophic Failure ◽  
Internal Temperature

The thermal management of a complex electro-optical system aimed for outdoor application is challenging task due to the requirement of having an air-sealed enclosure, harsh working environment, and an additional thermal load generated by sunlight. It is essential to consider the effect of heating loads in the system components, as well as the internal temperature distribution, that can have influence on the system life expectancy, operational readiness and parameters, and possibility for catastrophic failure. The main objective of this paper is to analyze internal temperature distribution and evaluate its influence on system component operation capability. The electro-optical system simplified model was defined and related thermal balance simulation model based on Solid Works thermal analysis module was set and applied for temperature distribution calculation. Various outdoor environment scenarios were compared to evaluate system temperature distribution and evaluate its influence on system operation, reliability, and life time in application environment. This work was done during the design process as a part of the electro-optical system optimization. The results show that temperature distribution will not be cause for catastrophic failure and malfunction operation during operation in the expected environment.

The Use of Thermography in Verification Tests of a Prototype Calorimeter Chamber

2014 ◽  
Vol 223 ◽  
pp. 238-245
Author(s):  
Tomasz Samborski ◽  
Andrzej Zbrowski
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Adverse Effects ◽  
Knowledge Base ◽  
Outer Surface ◽  
Thermal Conditions ◽  
Test Stand ◽  
Potential Threat ◽  
Proper Functioning ◽  
Control Methodology

The article discusses the use of thermography in verification tests of a prototype calorimeter chamber constituting a part of a test stand for actuators used in smoke and ventilation systems. Based on the prototype control methodology developed at the ITeE – PIB, the authors identified areas posing a potential threat to the proper functioning of the system. The measurements of the temperature distribution on the outer surface of the chamber in the identified areas (trouble spots) are shown. The measurements were taken in thermal conditions related to tests conducted in compliance with the procedures of normative environmental investigations. The article also discusses the scope of activities that need to be taken in order to eliminate the adverse effects of heat transfer (thermal bridges, welds, etc.). Based on the thermographic tests, the authors proposed some guidelines to be included in the knowledge base used in the design of similar systems.

scholarly journals In Situ Measurements of Energy Consumption and Indoor Environmental Quality of a Pre-Retrofitted Student Dormitory in Athens

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2210 ◽  
Author(s):  
Nikolaos Barmparesos ◽  
Dimitra Papadaki ◽  
Michalis Karalis ◽  
Kyriaki Fameliari ◽  
Margarita Niki Assimakopoulos
Keyword(s):  
Thermal Insulation ◽  
Social Impact ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Heating System ◽  
Energy Performance ◽  
In Situ Measurements ◽  
Indoor Environmental Quality ◽  
Electrical Consumption

In the following years all European Union member states should bring into force national laws on the energy performance of buildings. Moreover, university campus dormitories are buildings of great importance, due to their architectural characteristics and their social impact. In this study, the energy performance along with the indoor environmental conditions of a dormitory of a university has been analysed. The in situ measurements included temperature, relative humidity, concentrations of carbon dioxide, total volatile organic compounds, and electrical consumption; lastly, the energy signature of the whole building was investigated. The study focused on the summer months, during which significantly increased thermal needs of the building were identified. The ground floor was found to be the floor with the highest percentage of thermal conditions within the comfort range, and the third floor the lowest. Lastly, a significant correlation between electrical consumption and the outdoor temperature was presented, highlighting the lack of thermal insulation. Overall, it was clear that a redesign of the cooling and heating system, the installation of a ventilation system, and thermal insulation are essential for improving the energy efficiency of this building.

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