Top PDF A review of researches about human thermal comfort in semi-outdoor spaces

A review of researches about human thermal comfort in semi-outdoor spaces

A review of researches about human thermal comfort in semi-outdoor spaces

The enthusiasm of scientists to study on ther- mal comfort condition of semi-outdoor and out- door spaces has been raised since recent decade but it is needed to focus on more details and locations. Through representing a review on the prior stud- ies, it is understood that although the evaluation of thermal comfort in semi-outdoor spaces of various climates has been done up to now, the number of researches which specifically concentrate on to as- sess the human thermal comfort in semi-open ar- eas are few. Particularly, there is a lack of research- es on assessing thermal conditions of semi-outdoor areas in hot-humid regions. Moreover, it is need- ed to find a proper universal thermal index for vari- ous climate conditions. This index can help urban planner to evaluate thermal condition of districts in the world in understandable range. Finally, to pro- pose the practical software for simulation the ther- mal comfort of semi-outdoor spaces in easy and us- er-friendly manner.
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Outdoor thermal comfort and behaviour in urban area

Outdoor thermal comfort and behaviour in urban area

Architecture Department, Universitas Trisakti, Jakarta , Indonesia *Corresponding Author : inavona@trisakti.ac.id Abstract. Outdoor comfort is important due to the public spaces functions. Open spaces provide thermal comfort and a pleasant experience to improve the city life quality effectively. The influence of thermal comfort in outdoor activities is a complex problem. This paper presents a literature review and discussion of aspects of physical, psychology, and social behaviour toward outdoor thermal comfort. The valuation is determined not only by the “physical state” but also by the “state of mind”. The assessment is static and objective (i.e., physical and physiological characteristics) that it should be measured. Furthermore, an effective model to provide the knowledge of climatic conditions, as well as the dynamic and subjective aspects (i.e., psychological and social characteristics and behaviour), requires a comprehensive interview and observation. The model will be examined to describe the behaviour that is a reflection of perception and behaviour toward the environment. The adaptation process will constantly evolve so that it becomes a continuous cause between human behaviour and the spatial setting of the formation, which is eventually known as places and not just spaces. This evolutionary process is a civic art form.
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Outdoor thermal comfort by different heat mitigation strategies   a review

Outdoor thermal comfort by different heat mitigation strategies a review

Due to the ongoing global warming, heat mitigation strategies are becoming implemented through practice and simulations. These efforts aim to make the cities that are dealing with the urban heat island more livable. The effect of heat mitigation strategies on climate condition and energy consumption have been studied and compared, previously. In this paper, the effect of these strategies on human thermal comfort in urban open spaces is reviewed. Specifically, the review is focused on vegetation (in the form of parks, street trees, green roofs and green walls), and highly reflective materials (on roof and on the ground level) as the most common strategies for improving the thermal conditions in cities. Several studies done by simulation or through field measurement in different countries are described. The most important finding of the review is the fact that although highly reflective materials reduce air
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A review of thermal comfort

A review of thermal comfort

For the evaluation and prediction of outdoor thermal comfort, Nagano and Horikoshi (2011), Chen and Ng (2012) and Coccolo et al. (2016) have done a review of outdoor thermal comfort models. The major outdoor thermal comfort models are steady-state models. These models are based on the assumption that people’s exposure to an ambient climatic environment has, over time, enabled them to reach thermal equilibrium, and they provide numerical solutions to the energy balance equations governing thermoregulation (Chen & Ng, 2012). Even though the PMV- PPD index was originally developed for the evaluation of indoor thermal comfort, it is also commonly adopted in outdoor thermal comfort studies. The PET (Physiological Equivalent Temperature) (Mayer & Höppe, 1987) is another notable example of a steady-state model commonly used in outdoor thermal comfort research. PET is defined as the “air temperature at which the heat balance of the human body is maintained with core and skin temperature equal to those under the conditions being assessed” (Höppe, 1999). The PET model is particularly suitable for the evaluation of the outdoor thermal comfort in that it translates the evaluation of a complex outdoor climatic environment to a simple indoor scenario on a physiologically equivalent basis that can be easily understood and interpreted (Chen & Ng, 2012). A further development of PET is mPET (modified PET) that improves the capacity of the model to react to the change of relative humidity and clothing insulation (Chen & Matzarakis, 2014). Some other steady-state models-thermal stress (ITS) (Givoni, 1976), the OUT-SET (Pickup & de Dear, 2000), the COMFA (Kenny, Warland, Brown, & Gillespie, 2009), and the UTCI (Jendritzky, de Dear, & Havenith, 2012) are also applied in the outdoor thermal comfort studies. However, the steady-state models cannot effectively account for the dynamic aspects of the course of human thermal adaption (Chen & Ng, 2012). Many researches are developing non-steady-state models for the evaluation of outdoor thermal comfort based on field studies.
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Outdoor thermal comfort within five different urban forms in the Netherlands

Outdoor thermal comfort within five different urban forms in the Netherlands

Okeil [50] developed a built form named the Residential Solar Block (RSB), which was later compared with a slab and a pavilion court [51]. The RSB was found to lead to an energy-efficient neighbourhood layout for a hot and humid climate. Ali-Toudert and Mayer [52, 53] used the microclimate model ENVI-met to simulate the outdoor thermal comfort in the hot dry climate of Ghardaia, Algeria. They also studied the effect of different orientations of the urban canyon. It was concluded that the air temperature slightly decreases (and that the PET improves) when the aspect ratio of building height/canyon width (H/W) increases. Johansson [54] conducted
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Enhancement of Outdoor Thermal Comfort through Adoption of Environmental Design Strategies

Enhancement of Outdoor Thermal Comfort through Adoption of Environmental Design Strategies

The way of designing urban fabric, has a major effect on reducing the temperature of open space and can be used in a manner that enables users to use space in a permanent and convenient way. Thus, the relationship between the qualitative and quantitative effects of various parameters should be considered based on the orientation of the streets and time. Design and development of the urban environment requires the application of its components for improving the performance of elements that can be either the buildings and their orientation and shape, or the smaller objects in micro level such as trees, water and floor coverings. Tehran has three urban fabrics including open spaces, high-rise buildings and urban intense fabric that each one has their own optimum performance in thermal comfort. Since the street acts as a linear urban spaces and the main connector of noted texture, thermal comfort is very important for its users. Micro scale design for pedestrians to benefit from the sufficient wind and temperature is equally effective as the height of masses, location and orientation of buildings to lead the wind flows and receive adequate radiation in an urban site. The main question is what is the role of these elements in a linear open space design? Some of the urban landscape features such as the trees and water features (stream in streets) and sidewalks floorings have an influence in the amount of solar energy and wind flow in different ways and they can be useful in helping energy efficiency. 2.1. Methods
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Human thermal comfort in tropical climates

Human thermal comfort in tropical climates

The conditions for therm al com fort includes subjective or psychological factors in addition to the conditions listed for therm al neutrality. Rohles [13], one of the prom inent psychologists w ho review ed 5 previous studies that discussed the psychological aspect of therm al comfort, recom m ended a 3 d im en sio n al re p re se n ta tio n of the h u m a n b ein g in a th erm al environm ent. The m odel consists of a cuboid w ith each axis representing organism ic factors (age-sex, psyche, drive, body type, sensory process and genetics), physical factors (sound, light, volum e, radiation, inspired air, atm o sp h eric p ressu re , force fields, air m o v em en t, te m p e ra tu re an d relative hum idity) and reciprocative factors ( diet, clothing, exposure, social incentive and activity). The m odel has attributed the condition of m in d ' to n u m e ro u s facto rs, as above. W hile th e s tu d y is n o t com prehensive due to the small sam ple used, it should m ake an im pact on researchers w ho hold simplistic m odels of hum an com fort based on a set of physical factors only.
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A Model-Based Approach to Measuring the Effect of Shading on Outdoor Thermal Comfort

A Model-Based Approach to Measuring the Effect of Shading on Outdoor Thermal Comfort

system as shown in Fig. 1. The symmetric urban system comprises sixteen square blocks, although only the inner 9 blocks are considered for the mobility decisions. Each block measures m × n (m), and is occupied by a single building. The implication of this assumption is that the distance between buildings in each block is negligible. We consider building height and density as the design parameters of urban built form. For simplicity, it is assumed that all buildings have the same height h (m). Since building size is fixed for the case study presented in the next section, the difference in building density is a product of the distances between buildings. It is assumed that the distance between buildings equals the sum of the street and sidewalk width, thus making the entire block made up by a building with no front or dead spaces. Furthermore, we assume that population is evenly distributed in the specified urban system. The above assumptions allow us to examine and compare the impact of geometry alone, foregoing the complexities found in real urban textures. The attractiveness of these generic forms lie mainly in their simple and repeatable characteristics, which allows a more systematic comparative analysis on the effects of different design parameters on mobility patterns [6].
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Thermal comfort conditions in airport terminals: Indoor or transition spaces?

Thermal comfort conditions in airport terminals: Indoor or transition spaces?

There has been limited work, however, on the evaluation of the thermal environment in airport terminals and the investigation of the thermal comfort requirements for the different user groups. Balaras et al. took spot measurements of the thermal and visual conditions in three Greek airports for a week during summer. The study reported lack of proper humidity control and problems with temperature regulation in all three buildings, while through 285 questionnaires it highlighted the different satisfaction levels be- tween passengers and staff with all IEQ parameters [22] . The satisfaction with IEQ was also evaluated in eight Chinese airports where subjective and objective data were collected over a year. The study highlighted thermal issues such as overcooling and over- heating in several terminal spaces, however, the buildings were shown to underperform more in terms of acoustic environment and indoor air quality [23] . Environmental and subjective data were also collected from passengers in Terminal 1 at Chengdu Shuangliu International Airport, China, over a period of two weeks in summer and winter. Neutral temperature was 21.4  C in winter and 25.6  C in summer, with the respective comfort zones at 19.2 e23.1  C and 23.9 e27.3  C. Based on 569 questionnaires, the study reported that 78.3% of passengers were generally satis fied with the thermal environment and 95.8% considered the thermal conditions acceptable [24] . Another study surveyed 128 staff and passengers in the terminal of Ahmedabad airport, India, during the summer, and found a very high comfortable temperature range in the air- conditioned part of the building, 24 e32  C [25] . Ramis and dos Santos collected temperature and humidity data from three air- ports in Brazil. The temperature was found below the acceptable
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Investigation of adaptive thermal comfort in building transitional spaces

Investigation of adaptive thermal comfort in building transitional spaces

2.2 Physical Measurements At the same time when the questionnaire survey was carried out, the indoor environmental parameters including air temperature, relative humidity, air velocity and black globe temperature were monitored. The accuracy of the instrumentations used for the field studies complied with the requirements of ASHRAE 55-2013 (ASHRAE, 2013). Table 2 summarises the details of the instrumentations that were used in the field studies. Measurements covered the indoor transitional spaces including entrance lobby, atrium and café area. In order to ensure the readings were representative throughout the surveyed area, measurements had been taken in different locations within a space to identify the best measurement location. The air speed was measured at 15-minute intervals and all the other parameters were monitored at 1-minute intervals. The measurement locations were set at 1.1m height from the floor. For the outdoor environmental parameters, data were recorded every 5 minutes by a weather station which was installed on the rooftop of the Bute Building, the Architectural School of Cardiff University. The model of the weather station was Campbell Instruments CR10 data logger. The air temperature and relative humidity were measured by Rotronic temperature and humidity probe in a radiation shield.
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Thermal comfort in urban green spaces in arid environments.

Thermal comfort in urban green spaces in arid environments.

El “confort térmico” es concebido como la ausencia de malestar con el ambiente térmico (ASHRAE, 2014). Para el estudio del confort en los EVU de la ciudad de San Juan, se aplica el índice racional UTCI (Universal Thermal Climatic Index) (Jendritzky, de Dear y Havenith, 2012) para espacios abiertos, basado en la valoración de la respuesta fisiológica de la persona. El UTCI define 10 escalas de estrés térmico, que abarcan desde el estrés por calor extremo al causado por mucho frío. La escala de valoración se presenta en la Tabla 1.

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Wind characteristics and outdoor thermal comfort assessment in East Malaysia

Wind characteristics and outdoor thermal comfort assessment in East Malaysia

During southwest monsoon season, wind velocity is below 8m/s. Meanwhile, for northeast monsoon season, the wind velocity is in the range of 5 to 10 m/s. Generally, wind velocity is light and inconsistent during inter-monsoons seasons. Annually, Malaysia experiences monthly average relative humidity between 70% to 90%. Additionally, the country has around 6 hours of solar radiation per day on average (MetMalaysia, 2015). This study was aimed at enhancing our understanding of outdoor thermal environment in two different cities in East Malaysia, namely Kuching (i.e. Northwestern part of the Borneo island) and Kota Kinabalu (i.e. West coast of Sabah), as shown in Figure 1 and outlined in Table 1. The wind characteristics and outdoor thermal comfort levels were examined using weather data that correspond with the hot and humid tropical climate of Malaysia from two principal weather stations in Kuching and Kota Kinabalu.
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Urban outdoor thermal comfort of the hot-humid region

Urban outdoor thermal comfort of the hot-humid region

Thermal comfort can be perceived as one of the tools used to study the quality of the evironment in which humans live. It may function as an indicator to study changes in the physical environment in relation to human comfort level. Hence, it is suggested that urban monitoring in terms of its climate and landscape changes for Kuala Lumpur must be conducted and recorded closely because, as the biggest city in a developing country like Malaysia, Kuala Lumpur could not stop from experiencing rapid urban form changes or perhaps to slow down its processes due to inter-related needs of the economy and built environment in particular. However, in an attempt to improve the quality of life through economic development, the lives of the current and the future generations should not be jeopardized.
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Effect of the Shadings Pattern and Greenery Strategies on the Outdoor Thermal Comfort

Effect of the Shadings Pattern and Greenery Strategies on the Outdoor Thermal Comfort

Abstract—The outdoor thermal comfort is influenced by the perception and satisfaction of the pedestrians, especially in hot and arid climates. Accordingly, the researchers look for the appropriate methods to reduce the Urban Heat Island and thus to enhance the outdoor thermal comfort level of pedestrians. However, there is limited research conducted on the outdoor thermal comfort in hot and arid climate. This work is an investigation study conducted in an urban area (Haifa Street) in Baghdad city, characterized by an arid climate with very high temperatures in summer season reaching 50℃. This study focuses on investigating possible mitigation strategies to ensure how we could improve the thermal comfort at pedestrian level for an urban area with intricate Western design (high–rise buildings, a large spacing between the buildings, asymmetrical canyon geometry, and lack of vegetation). We created four different scenarios to assess the role of vegetation elements such as trees, grass, and different shading patterns. The evaluation was performed in the hottest day in summer. For each scenario, the mean radiant temperature, specific humidity, air temperature, and wind speed distributions have been analyzed using ENVI-met software. Thermal comfort is assessed using the PET thermal index (Physiological Equivalent Temperature) and Predicted Mean Vote (PMV). The results reveal that the PET index can be reduced to 10.4 ℃, the temperature can be decreased of about 2.4℃ and PMV to 3. The study shows how the urban factors such as the aspect ratio, vegetation cover, shadings, and geometry of the canyon are crucial elements that urban planners and municipalities have to take into account, especially for new urban developments. 
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Thermal comfort conditions in airport terminals: Indoor or transition

spaces?

Thermal comfort conditions in airport terminals: Indoor or transition spaces?

a b s t r a c t This paper reports on the investigation of the thermal comfort conditions in three airport terminals in the UK. In the course of seasonal field surveys, the indoor environmental conditions were monitored in different terminal areas and questionnaire-guided interviews were conducted with 3087 terminal users. The paper focuses on the thermal perception, preference and comfort requirements of passengers and terminal staff. The two groups presented different satisfaction levels with the indoor environment and significant differences in their thermal requirements, while both preferring a thermal environment different to the one experienced. The thermal conflict emerges throughout the terminal spaces. The neutral and preferred temperatures for passengers were lower than for employees and considerably lower than the mean indoor temperature. Passengers demonstrated higher tolerance of the thermal conditions and consistently a wider range of comfort temperatures, whereas the limited adaptive ca- pacity for staff allowed for a narrower comfort zone.
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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

the individual is an active member of the environment. Therefore, an individual thermal comfort can be determined by two factors. Namely, the body and its surrounding envi- ronment. Once one factor is altered, then an adjustment should be made to preserve the thermal equilibrium (Alah- mer et al. 2011 ). Humphreys and Nicol ( 2002 ) and Nicol and Humphreys ( 2002 ) suggested that “if a change occurs such as to produce discomfort, people react in ways which tend to restore their comfort” (p. 992). Although, this adaption may be conscious or unconscious (Holopainen et al. 2014 ). Clothing insulation also affects thermal comfort since gar- ments and the body are in a continuously dynamic condition (Huang 2006 ). Choi et al. ( 2012 ) suggested that since these two factors affect thermoregulation, an individuals’ heart rate can be considered as an additional index for thermal comfort. Gender subjective thermal comfort was shown by Parsons ( 2002 ) to be related to their clothing styles, fab- rics, and trends. The author noticed that women generally evaluate their thermal sensation cooler than men in cold environments. The Arabian traditional garments can provide adequate insulation for optimal thermal comfort under hot and arid conditions (Al-ajmi et al. 2008 ).
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Proposition of Regression Equations to  Determine Outdoor Thermal Comfort in Tropical  and Humid Environment

Proposition of Regression Equations to Determine Outdoor Thermal Comfort in Tropical and Humid Environment

people in normal condition without any feel of fatigue. If all the samples/respondents were not tired in each stage of activity, it would be able to get 5 (five) votes/answers of the questionnaire from each sample, we have chance to get as many as 5 x 60 = 300 data votes/answers. Consequently because of the respondents who got fatigue, lead to a reduced number of data votes/answers, which in this case, in the end, the data obtained only 213 votes/answers from the samples/respondents who walked speedy, consists of 73 votes from the samples who walked in a shaded area and 140 votes from the respondents who walked under the direct sunlight. The results of correlational analysis shown in Table 6, where the “highest” correlation coefficient is between the vote (comfort level) and the mean radiant temperature (Trm), ie, with correlation coefficient 0.403, which it means a correlation "less strong" between the two variables. If Trm will be used as inputs in the regression equation, then the variable Trm (mean radiant temperature) play the most important role as determinant variable in the equation, followed by another variable that correlated "rather weak" that is RH (relative humidity). Other variables those are: Adu (body size/area of human skin), v (wind velocity), and clo (clothing) do not adequate to influence, even it does not correlate or correlated very low with a level of comfort, where the coefficient of correlation to comfort level (vote), is relatively very small (Table 6).
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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

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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Impact of Street Canyon Geometry on Outdoor Thermal Comfort and Weather Parameters in Pécs

Impact of Street Canyon Geometry on Outdoor Thermal Comfort and Weather Parameters in Pécs

4. Methodology The importance of new green branches of science aiming to find solutions to environmental challenges has been internationally considered as undisputable [7]. Numerical simulations using ENVI-met code were applied due to its high capabilities and few data entries. The program uses a three-dimensional computational fluid dynamics and energy balance model; the simulation study can analyze unlimited number of points in the model. It is used to simulate the impact of certain urban design strategies on thermal comfort at a certain location [8]. Nonetheless, the study is limited to the moderately warm-wet climate of Pecs. Although some of the findings may be generalized, the conclusions of the study are not necessarily valid throughout moderately warm-wet climate groups, since there are climatic and considerable variations between different cities in terms of size, planning principles, proximity to the sea, and topography, etc. Moreover, visual and acoustical comfort performance is not investigated here. Moreover, due to the diverse scenarios and meteorological conditions, the field measurements could not give the total conclusion. In contrast, the Computational Fluid Dynamics (CFD) simulation method plays an important role in the research because of its means of modeling simplified and optimized. However, the methodology will be divided into four sections first one is describing the selected study site, second analyzing the street canyons of the chosen case, and summarizing the street canyon of the case study features, third, applying the ENVI-met software to simulate the urban microclimate with different street canyon geometries. Nevertheless, fourth section discusses the simulated results as well as draws the related conclusion.
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Desiccant Cooling System for Thermal Comfort: A Review

Desiccant Cooling System for Thermal Comfort: A Review

The most important concluding remarks in this study are: Some desiccant cooling cycles have been analyzed and suggested a most efficient desiccant cooling cycle for selected climatic conditions. Direct and indirect evaporative cooling methods can be used for different cycles of desiccant cooling system. Many studies emphasized on the optimization of operating parameters and used exergetic manufacturing cost (EMC) method for deciding the minimum regeneration temperature and R/P ratio. The effect of different operating parameters on the performance of desiccant cooling system analysed and presented minimum running cost. Optimum wheel speed of about 17.5 rpm for high moisture removal and maximum COP. The R/P ratio, regeneration temperature, desiccant material, rotation of desiccant wheel, outdoor conditions etc. are the important parameters which affect the performance of desiccant wheel. The operating cost of the desiccant system in summer Italian conditions, interesting saving up to 35% are obtained and reduced thermal cooling power up to 52% and pay back period obtained about 5-7 years. Among the Ventilation, Recirculation and Dunkle cycle, the Dunkle cycle is better for wide range of outdoor conditions. Many studies evaluated the performance of different desiccant material and found the material which has the higher moisture adsorption capacity. Hybrid desiccant cooling system economies 37.5 % electricity power when the process air temperature and relative humidity are maintained at 30 ºC, and 55% respectively. Solar energy may be suitable option for regeneration of desiccant cooling system and it saves the regeneration power. Some studies stressed the energy saving potential by solar assisted desiccant cooling system. Mathematical modeling and simulation study of solar based desiccant cooling system performed by some researchers. A composite wheel can be absorbs more moisture than conventional desiccant wheel with same operating conditions. Compounding of desiccant wheel obtained the greater moisture adsorption rate. Some researchers applied the system in different fields and proved the feasibility of the DCS.
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