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Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2009. / Includes bibliographical references.

This research focussed on the identification, evaluation and recommendation of passive design strategies suitable for housing design in hot and dry climates in India. The term 'passive' refers to those design techniques which, in order to enhance thermal comfort, utilize the favourable and mininimize the unfavourable elements of the local climate. The objective of the research was to determine means by which reliance on mechanical means of achieving comfort and associated socio-economic costs can be minimized. The thesis is divided into two parts. The first part identifies and evaluates the passive design techniques used in the dwellings of pre-industrial and post-industrial cities located in hot and dry region in India. Climate, environmental problems (primarily cooling), and indoor comfort criteria were analysed to establish preliminary criteria for evaluating the thermal performance of design techniques. The main objective was to enable designers to identify those techniques which can be used in contemporary dwelling designs. The second part proposes strategies to incorporate passive techniques in contemporary housing design. General strategies recommended at various levels of design include the following: -minimize solar gain -minimize conductive heat flow -promote ventilation -minimize internal heat gains -promote radiant cooling -delay periodic heat flow -promote evaporative cooling -control high velocity wind -control glare These strategies, which recognize the comfort-related needs of dwelling occupants, promote the use of local construction practices. The application of passive techniques presents architects with a considerable scope for creativity in housing design. However, at the outset, it is necessary to define priorities in the selection of design strategies, and to ensure these priorities are addressed through each level of design. The strategies selected in this thesis emphasize the need for minimizing heat gain during day time, and maximizing heat loss at night. It is concluded from this research that the application of passive techniques in contemporary housing design allows for maintenance of most thermal comfort needs, thereby reducing reliance on mechanical means of control. At the same time, the use of passive techniques provides a potential for the housing designs to respond effectively to certain socio-cultural needs of the occupants. / Applied Science, Faculty of / Architecture and Landscape Architecture (SALA), School of / Received degree under the name Bhatia / Graduate

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Typescript, etc. / Digitized by Kansas State University Libraries

The work presented in this thesis investigates design, computer modelling and testing a sub-wet bulb temperature evaporative cooling system for space air conditioning in buildings. The context of this evaporative cooling technology design is specifically targeted at locations with a hot and dry climate such as that prevailing in most regions of Middle East countries. The focus of this technology is to address the ever-escalating energy consumption in buildings for space cooling using mechanical vapour compression air conditioning systems. In this work, two evaporative cooling configurations both based on sub-wet bulb temperature principle have been studied. Furthermore, in these designs, it was sought to adopt porous ceramic materials as wet media for the evaporative cooler and as building element and use of heat pipes as heat transfer devices. In the first test rig, the prototype system uses porous ceramic materials as part of a functioning building wall element. Experimental and modelling results were obtained for ambient inlet air dry bulb temperature of 30 and 35oC, relative humidity ranging from 35% to 55% and intake air velocity less than 2 (m/s). It was found that the design achieved sub-wet bulb air temperature conditions and a maximum cooling capacity approaching 242 W/m2 of exposed ceramic material wet surface area. The wet bulb effectiveness of the system was higher than unity. The second design exploits the high thermal conductivity of heat pipes to be integrated as an effective heat transfer device with wet porous ceramic flat panels for evaporative cooling. The thermal performance of the prototype was presented and the computer model was validated using laboratory tests at temperatures of 30 and 35oC and relative humidity ranging from 35% to 55%. It was found that at airflow rates of 0.0031kg/s, inlet dry-bulb temperature of 35oC and relative humidity of 35%, the supply air could be cooled to below the inlet air wet bulb temperature and achieve a maximum cooling capacity of about 206 W/m2 of wet ceramic surface area. It was shown that the computer model and experimental tests are largely in good agreement. Finally, a brief case study on direct evaporative cooling thermal performance and environmental impact was conducted as part of a field trip study conducted on an existing large scale installation in Mina Valley, Saudi Arabia. It was found that the evaporative cooling systems used for space cooling in pilgrims’ accommodations and in train stations could reduce energy consumption by as much as 75% and cut carbon dioxide emission by 78% compared to traditional vapour compression systems. This demonstrates strongly that in a region with a hot and dry climate such as Mina Valley, evaporative cooling systems can be an environmentally friendly and energy-efficient cooling system compared to conventional vapour compression systems.

Increased consciousness of the environmental problems has aroused people’s interest of renewable energy systems, especially the application of green features in buildings. The demand for air conditioning / cooling in domestic and non-domestic buildings is rising throughout the world; this increases the reliance on conventional fuels and the global warming effect from greenhouse gas emissions. Passive cooling and energy efficient design can substantially reduce reliance on fuel based heating and cooling. Passive and Hybrid Downdraught Cooling, in different forms, is now technically viable in many parts of the world. This has been established through a combination of research projects. In some hot arid regions, a major part of the energy consumed consists of air-conditioning requirements. Alternative methods, using passive cooling techniques, can assist in reducing the conventional energy consumption in buildings. Evaporative cooling, which can be tracked back several hundreds of years in ancient Egypt and Persia [1–3], is one of the most effective strategies, because of the enormous latent heat needed for evaporation of water. Green features are architectural features used to mitigate migration of various air-borne pollutants and transmission of air from outside to indoor environment in an advantageous way [9]. The reduction of fossil fuel consumption and the associated decrease in greenhouse gas emissions are vital to combat global warming and this can be accomplished, in part, by the use of natural ventilation. To assess the performance of several innovative cooling systems devices and to develop improved models for more established technology, quantitative measurement of output was necessary. This was achieved in this study by the development of simply constructed low energy cooling systems which were calibrated by the innovative use of wind and water as a source. These devices were found to be consistent and accurate in measuring the temperature and cooling load from a number of devices. There were some problems in the original evaporative units. Therefore, a number of modifications have to be made to enhance the systems performance. The novel Windcatcher – PEC cooling system was assessed and different cooling loads were achieved.

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