The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Akwasi Ayensu - One of the best experts on this subject based on the ideXlab platform.
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dehydration of food crops using a solar dryer with convective heat flow
Solar Energy, 1997Co-Authors: Akwasi AyensuAbstract:A solar drying system designed on the principles of convective heat flow was constructed from local materials (wood, metals and glass sheets) and used to dry food crops (cassava, pepper, okro, groundnuts, etc.). The solar collector could transfer 118 W m−2 thermal power to the drying air. The thermal exchanges within the dryer were determined from a Psychometric Chart. Ambient air at 32°C and 80% relative humidity (RH) could be heated to 45°C at 40%. The crops were dried to a final moisture content of <14% and were preserved for a period of one year without deterioration. The low-temperature drying system ensured the viability of the seeds for planting. The drying process can be represented by an empirical equation of the form M(t)=MOexp (−kt) or dM/dt=−kM, where MO is the initial moisture content, M(t) is the moisture content at time t, and k is the drying constant. Under identical conditions, a high value of k was correlated with a shorter drying period. The drying process takes place in two phases: constant rate and falling rate periods, and the drying equation was solved to predict the total drying time. The mechanisms for the dehydration are the removal of unbound “free” water in the cell cavities and of “bound” water (water films) trapped within cells or chemically bound with solids as water of crystallization.
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Dehydration of food crops using a solar dryer with convective heat flow
Solar Energy, 1997Co-Authors: Akwasi AyensuAbstract:A solar drying system designed on the principles of convective heat flow was constructed from local materials (wood, metals and glass sheets) and used to dry food crops (cassava, pepper, okro, groundnuts, etc.). The solar collector could transfer 118 W m−2 thermal power to the drying air. The thermal exchanges within the dryer were determined from a Psychometric Chart. Ambient air at 32°C and 80% relative humidity (RH) could be heated to 45°C at 40%. The crops were dried to a final moisture content of
Amitesh Kumar - One of the best experts on this subject based on the ideXlab platform.
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Proposal and month-wise performance evaluation of a novel dual-mode evaporative cooler
Heat and Mass Transfer, 2019Co-Authors: Sarvesh Kashyap, Jahar Sarkar, Amitesh KumarAbstract:Three climatic zones (composite, hot-dry, hot-humid) cover most of the regions in India. Direct evaporative cooler is suitable for dry and indirect regenerative evaporative cooler is suitable for humid months. To avoid the use of two different coolers for the same purpose during the composite climate (significant seasonal variations of temperature and humidity), a novel two-in-one evaporative cooler is proposed and numerically investigated in this study. Proposed cooler takes advantage of both types of evaporative cooler and be operated in dual mode: acts as direct evaporative cooler for hot-dry and acts as regenerative indirect evaporative cooler for hot-wet seasons. The working of both modes (direct and regenerative) is explained with the help of a diagram. Effects of channels height and water flow rate on cooling capacity, wet bulb effectiveness, and dew point effectiveness are discussed. The month-wise performance of the proposed cooler is evaluated for five Indian cities (Bhopal, Lucknow and Varanasi of composite climate; Ahmedabad of hot-dry climate; Kolkata of hot-humid climate). Suitability of the modes in hot months (April to September) and cities are evaluated with the help of a Psychometric Chart. Study reveals that the proposed cooler can be effectively and economically used for composite climate.
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Proposal and month-wise performance evaluation of a novel dual-mode evaporative cooler
Heat and Mass Transfer, 2019Co-Authors: Sarvesh Kashyap, Jahar Sarkar, Amitesh KumarAbstract:Three climatic zones (composite, hot-dry, hot-humid) cover most of the regions in India. Direct evaporative cooler is suitable for dry and indirect regenerative evaporative cooler is suitable for humid months. To avoid the use of two different coolers for the same purpose during the composite climate (significant seasonal variations of temperature and humidity), a novel two-in-one evaporative cooler is proposed and numerically investigated in this study. Proposed cooler takes advantage of both types of evaporative cooler and be operated in dual mode: acts as direct evaporative cooler for hot-dry and acts as regenerative indirect evaporative cooler for hot-wet seasons. The working of both modes (direct and regenerative) is explained with the help of a diagram. Effects of channels height and water flow rate on cooling capacity, wet bulb effectiveness, and dew point effectiveness are discussed. The month-wise performance of the proposed cooler is evaluated for five Indian cities (Bhopal, Lucknow and Varanasi of composite climate; Ahmedabad of hot-dry climate; Kolkata of hot-humid climate). Suitability of the modes in hot months (April to September) and cities are evaluated with the help of a Psychometric Chart. Study reveals that the proposed cooler can be effectively and economically used for composite climate.
Sarvesh Kashyap - One of the best experts on this subject based on the ideXlab platform.
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Proposal and month-wise performance evaluation of a novel dual-mode evaporative cooler
Heat and Mass Transfer, 2019Co-Authors: Sarvesh Kashyap, Jahar Sarkar, Amitesh KumarAbstract:Three climatic zones (composite, hot-dry, hot-humid) cover most of the regions in India. Direct evaporative cooler is suitable for dry and indirect regenerative evaporative cooler is suitable for humid months. To avoid the use of two different coolers for the same purpose during the composite climate (significant seasonal variations of temperature and humidity), a novel two-in-one evaporative cooler is proposed and numerically investigated in this study. Proposed cooler takes advantage of both types of evaporative cooler and be operated in dual mode: acts as direct evaporative cooler for hot-dry and acts as regenerative indirect evaporative cooler for hot-wet seasons. The working of both modes (direct and regenerative) is explained with the help of a diagram. Effects of channels height and water flow rate on cooling capacity, wet bulb effectiveness, and dew point effectiveness are discussed. The month-wise performance of the proposed cooler is evaluated for five Indian cities (Bhopal, Lucknow and Varanasi of composite climate; Ahmedabad of hot-dry climate; Kolkata of hot-humid climate). Suitability of the modes in hot months (April to September) and cities are evaluated with the help of a Psychometric Chart. Study reveals that the proposed cooler can be effectively and economically used for composite climate.
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Proposal and month-wise performance evaluation of a novel dual-mode evaporative cooler
Heat and Mass Transfer, 2019Co-Authors: Sarvesh Kashyap, Jahar Sarkar, Amitesh KumarAbstract:Three climatic zones (composite, hot-dry, hot-humid) cover most of the regions in India. Direct evaporative cooler is suitable for dry and indirect regenerative evaporative cooler is suitable for humid months. To avoid the use of two different coolers for the same purpose during the composite climate (significant seasonal variations of temperature and humidity), a novel two-in-one evaporative cooler is proposed and numerically investigated in this study. Proposed cooler takes advantage of both types of evaporative cooler and be operated in dual mode: acts as direct evaporative cooler for hot-dry and acts as regenerative indirect evaporative cooler for hot-wet seasons. The working of both modes (direct and regenerative) is explained with the help of a diagram. Effects of channels height and water flow rate on cooling capacity, wet bulb effectiveness, and dew point effectiveness are discussed. The month-wise performance of the proposed cooler is evaluated for five Indian cities (Bhopal, Lucknow and Varanasi of composite climate; Ahmedabad of hot-dry climate; Kolkata of hot-humid climate). Suitability of the modes in hot months (April to September) and cities are evaluated with the help of a Psychometric Chart. Study reveals that the proposed cooler can be effectively and economically used for composite climate.
Shady Attia - One of the best experts on this subject based on the ideXlab platform.
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Comparative bioclimatic approach for comfort and passive heating and cooling strategies in Algeria
Building and Environment, 2019Co-Authors: Samir Semahi, Noureddine Zemmouri, Manoj Kumar Singh, Shady AttiaAbstract:Abstract The energy consumption and thermal comfort in buildings are heavily affected by weather conditions. Therefore, the aim of this paper is to analyze the bioclimatic potential of Algerian climate zones. This analysis was made based on eight representative locations using recent weather datasets (2003–2017). The thermal comfort and passive design potential analysis were based on a Psychometric Chart applying the adaptive comfort model ASHRAE 55–2017. In addition, an evaluation of the bioclimatic potential was conducted using simulations of a monitored and calibrated residential building model in Algeria using EnergyPlus. The building model has been tested in eight previously selected locations. The heating and cooling energy load results were calculated for each climatic zone and compared. The results allow architects and urban planners to better understand the climate and provide practical design guidance.
Goutam Kr. Panda - One of the best experts on this subject based on the ideXlab platform.
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Thermal comfort in naturally ventilated office buildings in cold and cloudy climate of Darjeeling, India – An adaptive approach
Energy and Buildings, 2018Co-Authors: Samar Thapa, Ajay Kr. Bansal, Goutam Kr. PandaAbstract:Abstract Thermal comfort standards are essential to determine a good indoor climate as well as to optimize energy use inside a building. The Predicted Mean Vote (PMV) model is used to determine the indoor comfort limits in a conditioned building. However, PMV model often exaggerates thermal sensation, as it does not include adaptation undertaken by the subjects in the real environment. These adaptive effects depend upon factors like local climatic condition, ethnicity, culture, etc. In this paper the results of adaptive thermal comfort based field studies conducted in 3 naturally ventilated office buildings of cold and cloudy climate in north east India are presented. The variation in thermal sensation, thermal preference, clothing insulation, neutral temperatures and other behavioral adaptive measures undertaken by the subjects like taking hot and cold beverages, number of showers in order to feel comfortable are discussed. The comfortable thermal sensation votes are plotted on the Psychometric Chart and a comparison with the comfort zone prescribed by ASHRAE is made. The subjects were found to be comfortable in cooler temperature than that prescribed in the standard, and thereby a modification in the comfort zone, which reflects the adaptive action of the subjects for the region is proposed.