Top PDF Analysis of the effect and responsiveness of physiology factors on thermal comfort in an air-conditioned environment

Analysis of the effect and responsiveness of physiology factors on thermal comfort in an air-conditioned environment

Analysis of the effect and responsiveness of physiology factors on thermal comfort in an air-conditioned environment

Monteith, J.L. (1973). Principles of environmental physics. London: Arnold. Moon, J.W. (2009). ANN based model free thermal controls for residential buildings. Ph.D. Thesis. The University of Michigan, USA. Mora-Rodriguez, R., Coso, J.D., Hamouti, N., Estevez, E. and Ortega, J.F. (2010). Aerobically trained individuals have greater increases in rectal temperature than untrained ones during exercise in the heat at similar relative intensities.

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Thermal comfort investigation of an outdoor air-conditioned area in a hot and arid environment

Thermal comfort investigation of an outdoor air-conditioned area in a hot and arid environment

Measured data analysis Field survey and measuring tools An overall of 407 participants were interviewed as 192 during summer 2014 and 215 during summer 2015. The surveys were focused on nonathletes adults sitting for approximately 2 h and did not perform any physical exercise prior to taking the survey. Thus, the exposure to the specific environmental conditions was long enough to define their thermal comfort condition. The main objective is to combine temperature and relative humidity in terms of population’s comfort zone. The vast majority of the sample (over 95%) indicated no health problems such as asthma or recent surgeries. Thus, it is assumed that the recorded thermal sensation was not affected by any medical factors. The clothing insulation of men was 0.36–0.61 clo and for those wearing the traditional Arab cloth (Thob) was 1.05–1.23 clo while for women, the thermal clothing insulation is 0.57–0.61 clo and for those wearing the traditional women dress (Abaya) was 1.19–1.24 clo (Al-ajmi et al. 2008 ; ASHRAE 55:2004 2004 ). The survey selected a representative sample that accurately reflects the entire residents in Qatar. A total of 407 participants were interviewed face-to-face. The participants were 230 men and 177 women with the percentage distribution to be 56% and 44%, respectively. Eight out of ten of the participants for 2014/2015 summers were from the Middle East and North Africa (MENA) region and Asia which are considered to be relatively familiar with the local hot and arid climatic conditions. The rest of the individuals came from different
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Perception of the thermal environment in library centre at UTeM : subjective preferences and thermal comfort due to air conditioning system

Perception of the thermal environment in library centre at UTeM : subjective preferences and thermal comfort due to air conditioning system

Thermal comfort is an adaptation of the human body, tends to accept environmental conditions. A person’s perception of thermal comfort is affected by air temperature, relative humidity, air velocity, mean radiant temperature, metabolic rate for work activities and clothing insulation. The demand for conducive high efficient air conditioned office building provides a thermally acceptable environment for human comfort and work that would in order to enable better work productivity performance and less occupant’s thermal dissatisfaction. In recognizing the significance of thermal comfort level to occupants, the main objective of the study is to determine the thermal environment perception among UTeM’s library staffs to the existing air conditioning system in their workplace by means of both qualitative and quantitative approaches. Determination of occupants’ perception on thermal comfort was obtained through observation and analysis method associated with a questionnaire on thermal comfort with respect to findings of objective measurement. Measurement of actual thermal comfort in work units was conducted by direct reading monitoring linked with thermal comfort instruments to determine the PMV and PPD values. Further to this study, it shown that the perception of library staffs on thermal environment in their workspace is at moderate level (more than 60%). The result indicated besides the substantial role of environmental factors, thermal adaptation and psychological parameters strongly affect human thermal comfort. Maintaining on AC system of the research building should be taken into consideration to produce good thermal environment.
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Effect of Dynamic Vents on the Thermal Comfort of a Passenger Car

Effect of Dynamic Vents on the Thermal Comfort of a Passenger Car

Much research has been carried out to enhance the thermal comfort inside the passenger car. Chen et al. [3] in their research suggested an energy efficient way of delivering comfort to an occupant in the car. Their research focused on the design and CFD analysis of an energy efficient HVAC system with spot cooling by strategically placing multiple nozzles in the vehicle directed at specific body parts. In their experiment the nozzle design and nozzle locations were paramount to deliver and achieve energy efficiency. In another research paper on the design of dynamic air vents and airflow analysis in a passenger car cabin by Varad et al. [4] they suggested the concept of dynamic vents. They analyzed the effect of dynamic vents and compared them with the steady air vent model. The results projected a considerable drop in the average cabin temperature. They also noted various effects of dynamic air vents. Walgama et al. [5] in their paper classified the work with respect to the passenger compartment environment or the condition of the passengers and their interaction with the compartment. The effects of factors such as flow field and temperature field were taken into consideration. They proposed computational and empirical models for forecasting thermal comfort in the non-uniform transient environment of the passenger car. Studies of air-flow and temperature fields inside a passenger compartment for improving thermal comfort and saving energy was investigated by Zhang et al. [6]. They investigated the influence of different factors on thermal comfort and energy consumption. Temperature distributions and the flow field inside a passenger car were simulated and analyzed with and without passengers. Their simulation results revealed various factors that ameliorate the thermal comfort and energy consumption such as the significance of air inlet temperature and the external conditions. The results also showed that the number of passengers also affects the conditions. The window materials also influence the thermal insulation of the vehicle. To improve the uniformity of the temperature field around the driver’s foot zone a better flow circulation near the compartment bottom is favorable, for example, Ruzic [7].
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Thermal Comfort And Dust Concentration Level Analysis Of Air-Conditioned Lecture Rooms

Thermal Comfort And Dust Concentration Level Analysis Of Air-Conditioned Lecture Rooms

The definition of thermal comfort defined by ASHRAE Standard 55-1992 is a state of mind that satisfied with terms of environment. There are several factors of thermal comfort which are air temperature, average radiant temperature, relative humidity and air speed and the side factor obtained activity and clothing. Several factors that involving to rise the temperature in a building are emission of heat from the lights and electrical appliances, the admission of heat from outside to the walls, windows and roofs of building and heat convection of hot air from outside the building. The standard thermal comfort in Malaysia when the relative humidity (RH) between 45% - 80.6% and the temperature is between 25.5 o C – 28.5 o C in dry bulb temperature. (Nasir et al., 2011)
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Thermal Comfort Analysis of PMV Model Prediction in Air Conditioned and Naturally Ventilated Buildings

Thermal Comfort Analysis of PMV Model Prediction in Air Conditioned and Naturally Ventilated Buildings

PMV model over prediction in air conditioned buildings are the major feature of not satisfying the building environment standards. For improvement of building environment w.r.t PMV model the expected parameters such as metabolism rate and clothing factors need to be reexamined for better interpretation of thermal comfort. Tropical climatic region in summer season have a trend of 0,-1 and -2 actual thermal sensation vote which shows that subjects are overcooled as shown in fig. 3(c). Thus this finding leads to over consumption of energy in tropical climatic region. .
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THERMAL MODELING OF AIR- CONDITIONED PROTOTYPE ROOM USING MATLAB-SIMULINK

THERMAL MODELING OF AIR- CONDITIONED PROTOTYPE ROOM USING MATLAB-SIMULINK

Now in global warming era, it is requisite to work on reduction and optimization of the energy consumption in various fields, one such field is the residential sector. In residential sector the main energy consuming device is the HVAC (Heating, Ventilation and Air Conditioning) systems used for heating or cooling buildings. So to optimize the energy consumption in HVAC or Air-conditioning systems, the researchers has to be more concentrate on some important aspects as: the use of an adequate mathematical model of the building and efficient techniques to control physical parameters [Patil C. B. et al ,(2016); Radu Balan,(2011)]. To do such work the thermal performances of various elements in the whole system has to study. The thermal performance of a building refers to the process of modeling the energy transfer between a building and its surroundings. Now-a-days computer modeling is one of the widespread ways, used in the green building industry to predict energy consumption, thermal comfort and to size HVAC equipment [Roberto Padovani et al,(2011); Karmacharya et al, (2012)].
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The effect of using aluminium sheet for thermal comfort

The effect of using aluminium sheet for thermal comfort

This report is submitted to the Faculty of Engineering Technology of UTeM as a partial fulfillment of the requirements for the degree of Bachelor of Engineering Technology (Air Conditioning and Refrigeration System) (Hons.). The member of the supervisory is as follow:

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The Effect of Indoor Thermal Comfort on Visual Search Task Performances in a Personal Learning Environment

The Effect of Indoor Thermal Comfort on Visual Search Task Performances in a Personal Learning Environment

Why does performance level decrease rather than increase when indoor thermal comfort level - in other words, positive affectiveness - increases? One answer could be that the arousal level of each participant was higher than the arousal level for optimal performance [21]. According to the two-dimensional model of emotion, valence, i.e., comfort and discomfort, forms one axis, with arousal as another axis perpendicular to it. This suggests that the increase in comfort level is separate from any change in arousal level; thus, even if the perceived comfort level of the learning environment increases, it is possible that the impact of arousal on female students’ performance is separate from the impact of that. However, we examined the correlation between female students’ performance and their arousal level, and discovered that the correlation was not statistically significant. Based on this finding, the explanation that different arousal levels among students caused them to perform poorly during increased indoor thermal comfort is likely not appropriate.
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Investigation Of Air Flow In Chamber Using Air-Conditioning Unit For Thermal Comfort

Investigation Of Air Flow In Chamber Using Air-Conditioning Unit For Thermal Comfort

First and foremost, I wish to extend my heartfelt thanks to Mr. Shamsul Bahari Bin Azraai as the final year project supervisor who has gracefully offered his time, attention, experience and guidance throughout the completion of the investigation thus far. I would also like to extend my thanks to Mr. Asjufri Bin Muhajir, technician of Combustion Lab for his assistance and provision of information on the Air-Conditioning facilities at UTeM (industry campus). Thanks to the university library for providing lots of sources which assist to complete the report.

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Air Flow And Temperature Distribution Analysis In An Air Conditioned Car

Air Flow And Temperature Distribution Analysis In An Air Conditioned Car

3.3 General Boundary Conditions (Ivanescu et.al, 2010) 25 3.4 External Boundary Conditions (Ivanescu et.al, 2010) 25 3.5 Air Conditioning Unit Characteristics (Ivanescu et.al, 2010) 25 3.6 Experimental Results and Simulation Results for Air Velocity

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Influencing Factors and Improvement Strategies for Indoor Air Quality and Human Thermal Comfort in a Convenience Store

Influencing Factors and Improvement Strategies for Indoor Air Quality and Human Thermal Comfort in a Convenience Store

Figure 5 shows the airflow distribution in the indoor environment after door opening. In this figure, (a) and (b) show the airflow distribution at different heights, wherein part of the dead zone areas with low air velocity in the airflow distribution in the original space were improved; however, dead zone remained in some areas in the space. Figure 5(c) and Figure 5(d) are vertical airflow dis- tribution maps of the supply air outlet. The short-circuit phenomenon in the original space improved after door opening, mainly because the opening door leaded the airflow to move towards the door side and increased airflow in the space, thereby the areas of dead zone reduced in the indoor environment. The airflow originally flowing into the return air inlet was driven by other airflow to flow towards the door side, thus improving the short circuit.
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Thermal comfort and indoor air quality analysis of a low energy cooling windcatcher

Thermal Comfort and Indoor air Quality Analysis of a Low-energy Cooling Windcatcher

The windcatcher dates back to 1,500 years ago. Their usage was spread to Middle East countries such as Iran, Egypt and the UAE. Natural ventilation and passive cooling of the airflow without electrical power are the most important features of windcatchers [1]. In the UAE, windcatchers can be seen in the town of Bastakiya and signified a remarkable effort to attain comfortable living in a hot climate. Coles et al. [2] studied the effectiveness of UAE’s Bastakiya windcatchers by carrying out measurement of temperatures, wind tunnel modelling and interviews with previous residents. Recently, McCabe and Roaf [3] performed dynamic thermal modelling of a Bastakiya house centered on the windcatcher ventilation system using historical climate data. The study analysed the potential of traditional windcatchers to increase the comfort by varying the height and cross-sectional area. To this end, most of the studies on windcatchers in the UAE are mainly based on the traditional systems and many of these historic buildings © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
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Thermal comfort and indoor air quality analysis of a low-energy cooling windcatcher

Thermal comfort and indoor air quality analysis of a low-energy cooling windcatcher

Many researchers [1] have attempted to improve the effectiveness of windcatchers by increasing the ventilation rates and operation time. Several studies [1,4] focused on the aerodynamics design and ventilation performance of windcatchers. Recently, several works [5,6] have integrated heat pipes in windcatchers to improve its cooling performance in hot countries. The numerical analysis [5] showed that the temperature reduction of the supply air reached up to 12˚C while still providing the fresh air requirements. Figure 1 shows the operation of the cooling windcatcher with heat pipes. The hot outdoor air enters the windcatcher through the louvers. The airflow is driven downwards and passed through a series of heat pipes which absorbs the heat from the airflow (evaporator) and transfers it to a parallel cool sink (condenser). Adjustable dampers are mounted at the bottom of the deviceto control the delivery rate of the outdoor air, as fluctuations in external wind speed greatly influence the air movement rate within the occupied space. The cooled air is supplied to the room beneath the channel via ceiling diffusers. The current work expands on previous research [5,6] by investigating the capabilities of the system to provide good thermal comfort and indoor air quality in buildings.
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INFO 1.0. Greater safety and comfort in air-conditioned buildings. Actuators for heating, ventilation, air-conditioning

INFO 1.0. Greater safety and comfort in air-conditioned buildings. Actuators for heating, ventilation, air-conditioning

Actuators for HVAC systems. Belimo has been de- signing, manufacturing and marketing electric actuators for motorized control devices in heating, ventilating and air- conditioning systems since 1975. The company’s inno- vative, high-class technology ensures troublefree operation for all kinds of HVAC control devices. This not only means greater comfort and convenience, of course, but also greater safety for property and the occupants of buildings.

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Inlet and outlet configurations effect on thermal comfort

Inlet and outlet configurations effect on thermal comfort

Air conditioning is the process of treating air to meet the requirements of conditioned space by control simultaneously its temperature, humidity, cleanliness, and distribution. Thus air conditioning can also be described as the process of control the properties of air to more favourable or comfort condition. Typically, the purposes of air conditioning are to achieve comfort or improve comfort of surrounding. In the design of comfort air conditioning and ventilation systems, a few sources must be controlled such as odours arising from occupants, cooking, and heat from occupants. This will be accomplished by introducing fresh air or purified recirculated air in sufficient quantities to reduce these problems. It also can refer to any appearance of technology, heating, cooling, dehumidification, cleaning, ventilation or air movement that can modify the air condition. As described by the American Society of Heating,
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Air temperature, relative humidity, climate regionalization and thermal comfort of Nigeria

Air temperature, relative humidity, climate regionalization and thermal comfort of Nigeria

The relation between man and climate is reciprocal in the sense that man responds to variation in climate by insulating buildings, heating and air-conditioning. Man’s aim is to be comfortable despite the climate, and this gives rise to the notion of thermal comfort. Thermal comfort has been studied since the start of 20th century, and improvements in building techniques, as well as dis- coveries in central heating and air conditioning systems have led to improved comfort in indoors, even in the hottest and coldest climates (Brager and de Dear, 1998). Several indices of comfort and mathematical models to predict thermal comfort and discomfort have also been developed (G´omez et al., 2004; Watkinson et al., 2004; Kiang et al., 2006). For most indoor conditions, the effi- ciency of a person or group of people has been described ‘as being bound up in the climatic conditions in which they work and live’ (Han et al., 2007). Han et al. (2007) argued that buildings are designed to suit the climate within which they are located and the functions for which
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Thermal comfort and air quality in Chilean schools, perceptions of students and teachers

Thermal comfort and air quality in Chilean schools, perceptions of students and teachers

María Isabel Rivera 1,2 , Alison G. Kwok 1 1 University of Oregon, Eugene, Oregon 2 Universidad de Concepción, Concepción, Chile ABSTRACT: we present findings of naturally ventilated classroom conditions in primary school buildings in the city of Concepción, Chile, where there is no adherence to indoor environmental quality standards. We focused on thermal comfort and environmental perceptions of students and teachers, during fall and winter seasons. The goal is to examine the perceptions of children and teachers by analyzing responses to conditions in their classrooms, related to their socioeconomic context driven by school type. Approximately 888 students, aged 10-14 years old, were surveyed from nine schools during fall season, and 333 students from four schools during winter. A total of 2,271 subject responses were collected in two campaigns. Physical measurements included: ambient air temperature, relative humidity, airspeed, radiant temperature, and CO 2 . Simultaneous subjective responses were collected through electronic surveys on tablets which included questions on thermal sensation, thermal acceptability, and thermal preference. We examined thermal sensation trends, perceptions of comfort and air quality, across public, private-subsidized, private-nonsubsidized schools. Results show that about ~80% of teachers and students voted their thermal sensation primarily within the three central categories of the scale (-1, 0, +1). A small distinction can be seen in fall season in the private-subsidized school with a tendency towards a warm thermal sensation (+1), which corresponded to higher indoor temperatures. High indoor CO 2 concentration levels were measured in all of the classrooms, with a maximum of 4327 ppm in winter in public schools, and a minimum of 858 ppm in fall in private-subsidized schools.
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The effect of varying chilled ceiling position on thermal comfort

The effect of varying chilled ceiling position on thermal comfort

Chilled ceiling is the main part in Hydronic Radiant Cooling (HRC) system which offers appropriate cool for occupants by combining of thermal radiation and natural convection effect. The effect of varying chilled ceiling positions are tested at height 0.47m, 0.41m and 0.35m in environmental chamber for achieving thermal comfort condition.The limitations associated with conventional air-conditioning systems such as high energy consumption, poor ventilation and do not environmentally friendly are opened the door for find an alternative solution. Two purposes of this study are to investigate the possibility of accepting the chilled ceiling system as an alternative system towards the conventional air-conditioning system in Malaysia by adopting the proper HRC system design and to investigate room temperature by identifying the oppropriate height of the chilled ceiling panel for achieving thermal comfort temperature. Design and fabrication new model with implementing experimental work are the main approach to achieve standing objectives. An environmental chamber with the dimension of 0.7 m (L) × 0.5 m (W) × 0.5m (H) is used to conduct the experimental work. The most important parameters measured in this chamber are room temperature inside the chamber and relative humidity. The best height for chilled ceiling panel can be optimized at 0.35m for providing thermal comfort which is equal to 2.1m at the actual room with temperature of 24.6°C and relative humidity of 56.9%. It is expected that the chilled ceiling system can be applied in Malaysia associated with integrating independent system for dry air. Therefore, thermal comfort temperature can be achieved with energy reduction when the position of chilled ceiling panel is varied at optimum position. The current project is ready for contribution in saving energy and environment.
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The effect of pavement characteristics on pedestrians' thermal comfort in Toronto

The effect of pavement characteristics on pedestrians' thermal comfort in Toronto

Urban heat island (UHI) has proved to have an important effect in urban microclimate of large cities. In particular, the materials used for the pavements of urban spaces and sidewalks affect pedestrians’ comfort significantly. Dark materials store solar radiation during the day and re-radiate it overnight. Reversely, cool materials, given their high albedo, are often proposed for mitigating UHI issues. This paper focuses on the effect on the outdoor thermal comfort of different materials in a main urban square in Toronto. The study is performed at the neighborhood scale, using the high resolution software ENVI-met. Simulations done for a summer heat wave in 2015 allowed to predict the maximum effect of pavements with surfaces having different albedo. The physiological equivalent temperature (PET) is used to assess the pedestrians’ thermal comfort. The results show the relative effectiveness of different pavement materials. In particular, thermal comfort evaluations are reported to assess the microclimate benefits of bright marbles over black granites.
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