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D.G. Leo Samuel

Bio: D.G. Leo Samuel is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Passive cooling & Thermal comfort. The author has an hindex of 6, co-authored 11 publications receiving 194 citations. Previous affiliations of D.G. Leo Samuel include Motilal Nehru National Institute of Technology Allahabad.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the thermal behavior of this thermally activated glass fibre reinforced gypsum (TAGFRG) roof is analyzed experimentally in terms of diurnal temperature gradients, thermal images of the interior and exterior roof surfaces, decrement factor and water temperature variations.

12 citations

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TL;DR: In this article, the authors investigated the influences of three design parameters on thermal comfort of thermal activated building system (TABS) using COMSOL Multiphysics, a computational fluid dynamics (CFD) tool.
Abstract: Thermally activated building system (TABS) can be operated at relatively higher water temperature. Hence, it can be coupled with passive cooling systems. This paper investigates the influences of three design parameters on thermal comfort of TABS using COMSOL Multiphysics, a computational fluid dynamics (CFD) tool. For the same inlet velocity, an increase in the pipe inner diameter from 9 to 17 mm decreased the operative temperature (OT), a thermal comfort index, by 1.8°C. An increase in the pipe thermal conductivity from 0.14 to 1.4 W/mK reduced the average OT by 2.5°C. However, a further increase in thermal conductivity had no significant influence. For cooling pipes embedded at a constant depth, an increase in the thickness of both roof and floor from 0.1 to 0.2 m delayed and reduced the maximum OT by 48 minutes and 0.3°C, respectively.

11 citations

Journal ArticleDOI
TL;DR: In this article , a thermally activated glass fibre reinforced gypsum (TAGFRG) system is proposed to reduce both operational and embodied energy of the building by integrating the energy-efficient thermal activated building system (TABS) with the eco-friendly GFRG.

6 citations

Journal ArticleDOI
TL;DR: In this article , an energy-efficient thermally activated building system (TABS) is integrated with glass fiber reinforced gypsum (GFRG), an eco-friendly building material.
Abstract: Construction and operation of buildings are responsible for about 20% of the global energy consumption. The embodied energy of conventional buildings is high due to the utilization of energy-intensive construction materials and traditional construction methodology. Higher operational energy is attributed to the usage of power-consuming conventional air-conditioning systems. Therefore, moving to an energy-efficient cooling technology and eco-friendly building material can lead to significant energy savings and CO2 emission reduction. In the present study, an energy-efficient thermally activated building system (TABS) is integrated with glass fiber reinforced gypsum (GFRG), an eco-friendly building material. The proposed hybrid system is termed the thermally activated glass fiber reinforced gypsum (TAGFRG) system. This system is not only energy-efficient and eco-friendly but also provides better thermal comfort. An experimental room with a TAGFRG roof is constructed on the premises of the Indian Institute of Technology Madras (IITM), Chennai, located in a tropical wet and dry climate zone. The influence of indoor sensible heat load and the impact of natural ventilation on the thermal comfort of the TAGFRG system are investigated. An increase in internal heat load from 400 to 700 W deteriorates the thermal comfort of the indoor space. This is evident from the increases in operative temperatures from 29.8 to 31.5 °C and the predicted percentage of dissatisfaction from 44.5% to 80.9%. Natural ventilation increases the diurnal fluctuation of indoor air temperature by 1.6 and 1.9 °C for with and without cooling cases, respectively. It reduces the maximum indoor CO2 concentration from 912 to 393 ppm.

5 citations

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TL;DR: In this article, two widely used modeling techniques, multi-zone modeling and CFD modeling, were used to simulate the contaminant distribution in a mechanical ventilated environment and validated with field measurements made at Chennai, India.
Abstract: Rapid motorization in developed and developing countries demands more parking spaces in urban areas. Underground car parking space in multi story buildings offers viable solution. However, lack of natural ventilation accumulates the harmful emissions from cars, operating in underground car parks. Exposure to these hazardous pollutants causes health risk to the users. Therefore, proper mechanical ventilation system should be adopted for the removal of harmful pollutants. This paper discusses the usage of modeling and simulation tools in the design of the mechanical ventilation system. Two widely used modeling techniques, multi-zone modeling and CFD modeling were used to simulate the contaminant distribution in a mechanical ventilated environment. The former provides an approximate macroscopic solution of the carbon monoxide (CO) distribution, while the later provides precise distribution of CO contours. The two models were validated against field measurements made at Chennai, India. The model predictions were very close to the actual site measurements. The impact of garage height and CO generation rate on ventilation requirement has been analysed

5 citations


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Journal ArticleDOI
TL;DR: The basic principles of radiative cooling and its performance characteristics for nonradiative contributions, solar radiation, and atmospheric conditions are discussed and the recent advancements over the traditional approaches and their material and structural characteristics are outlined.
Abstract: The recent progress on radiative cooling reveals its potential for applications in highly efficient passive cooling. This approach utilizes the maximized emission of infrared thermal radiation through the atmospheric window for releasing heat and minimized absorption of incoming atmospheric radiation. These simultaneous processes can lead to a device temperature substantially below the ambient temperature. Although the application of radiative cooling for nighttime cooling was demonstrated a few decades ago, significant cooling under direct sunlight has been achieved only recently, indicating its potential as a practical passive cooler during the day. In this article, the basic principles of radiative cooling and its performance characteristics for nonradiative contributions, solar radiation, and atmospheric conditions are discussed. The recent advancements over the traditional approaches and their material and structural characteristics are outlined. The key characteristics of the thermal radiators and solar reflectors of the current state-of-the-art radiative coolers are evaluated and their benchmarks are remarked for the peak cooling ability. The scopes for further improvements on radiative cooling efficiency for optimized device characteristics are also theoretically estimated.

430 citations

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TL;DR: In this article, a literature review on the basic and applied research in RHC systems for the built environment is conducted, in terms of thermal comfort, thermal analysis including heat transfer model, heating/cooling capacity, CFD analysis, energy simulation, system configuration and control strategies.

322 citations

Journal ArticleDOI
TL;DR: In this paper, a detailed literature survey of published studies on selective emitter structures for daytime and nighttime cooling purposes is presented and a detailed energy analysis is performed identifying key performance indicators and evaluating the cooling performance under various conditions.

240 citations

Journal ArticleDOI
TL;DR: In this paper, a review-based framework is proposed to represent occupant behavior in buildings by arguing that occupants are not illogical and irrational but rather that they attempt to restore their comfort in the easiest way possible, but are influenced by many contextual factors.

233 citations

Journal ArticleDOI
Xing Lu1, Peng Xu1, Huilong Wang1, Tao Yang1, Jin Hou1 
TL;DR: In this article, the authors reviewed the trends of passive radiative cooling (PRC) techniques, as well as advancements in recent years, with an attempt being made to analyze the cooling magnitude and developmental prospects for both diurnal and nocturnal periods.
Abstract: The universe can be utilized as a sink for heat pumping by means of passive radiative cooling (PRC). This approach is an age-old cooling practice that has had a renaissance with increasing numbers of research papers over the past two decades. This paper reviews the trends of this technique, as well as advancements in recent years, with an attempt being made to analyze the cooling magnitude and developmental prospects for both diurnal and nocturnal periods. The models and calculations for computing the performances of passive radiative cooling systems are discussed along with the designs and fabrication factors that influence a system's performance. Optimizing strategies that maximize the net cooling power are also presented. The various system configurations that are available to date are summarized to demonstrate the building integration forms of PRC systems. The cooling potentials of different systems are assessed by simulations, and it is shown that the daytime cooling energy density is rather modest, even under the most favorable conditions. The barriers that likely exist to widespread application as well as the scopes for further improvements of PRC are also provided. It is noted that the commercialization of PRC systems is primarily limited by coating material constraints and technique reliability. The advent of a new type of material will be a critical solution to the prevalence of PRC.

187 citations