PERFORMANCE EVALUATION OF LOW EXERGY SYSTEMS DEPICTING DECENTRALIZED DEDICATED OUTDOOR AIR SYSTEM COUPLED WITH RADIANT COOLING IN THE TROPICS

Ph.DDOCTOR OF PHILOSOPH

Stuck in a stack—Temperature measurements of the microclimate around split type condensing units in a high rise building in Singapore

AbstractThe use of air-conditioning, the largest energy demand for buildings in the tropics, is increasing as regional population and affluence grow. The majority of installed systems are split type air-conditioners. While the performance of new equipment is much better, the influence of the microclimate where the condensing units are installed is often overlooked. Several studies have used CFD simulations to analyse the stack effect, a buoyancy-driven airflow induced by heat rejected from condensing units. This leads to higher on-coil temperatures, deteriorating the performance of the air-conditioners. We present the first field measurements from a 24-storey building in Singapore. A network of wireless temperature sensors measured the temperature around the stack of condensing units. We found that the temperatures in the void space increased continuously along the height of the building by 10–13°C, showing a significant stack effect from the rejected heat from condensing units. We also found that hot air gets stuck behind louvres, built as aesthetic barriers, which increases the temperature another 9°C. Temperatures of around 50°C at the inlet of the condensing units for floors 10 and above are the combined result, reducing the unit efficiency by 32% compared to the undisturbed design case. This significant effect is completely neglected in building design and performance evaluation, and only with an integrated design process can truly efficient solutions be realised

GPML: an XML-based standard for the interchange of genetic programming trees

We propose a Genetic Programming Markup Language (GPML), an XML based standard for the interchange of genetic programming trees, and outline the benefits such a format would bring in allowing the deployment of trained genetic programming (GP) models in applications as well as the subsidiary benefit of allowing GP researchers to directly share trained trees. We present a formal definition of this standard and describe details of an implementation. In addition, we present a case study where GPML is used to implement a model predictive controller for the control of a building heating plant

Performance evaluation of damper control settings for operation of multiple-zone variable air volume reheat system in different building applications and climate types

Choosing the right control strategies is an important task for effective operation of variable air volume reheat (VAVR) system in commercial buildings. In this design, dampers’ position inside air terminal units (ATUs) are modulated to adjust the amount of air supply volume based on thermal zones’ cooling or heating demand. A minimum air flow fraction (MAFF) is set for damper settings of ATUs to avoid under-ventilation problem in thermal zones. This study investigated the impact of MAFF value on various performance aspects of multiple-zone VAVR design in different building applications and climate types. A five-storey commercial building for three applications of school, office and retail in four climate types of tropical monsoon, hot desert, Mediterranean and humid continental have been simulated in EnergyPlus building simulation software. The results of simulations have shown that lowering MAFF value in ATUs would reduce the required reheat coil energy to maintain precise air supply temperature at part load cooling scenarios. Nonetheless, this reduction could have some implications on thermal comfort and indoor air quality level of thermal zones in a multiple-zone arrangement. It was concluded that in general it is an energy efficient control strategy to keep MAFF value to as low as 0.1 for high ventilation rate spaces like classrooms in school buildings (except for hot desert climate). On the other hand, it is advisable to not reduce MAFF value below 0.3 for low ventilation rate spaces like office areas to avoid any air quality issues in thermal zones

Knowledge and Attitude of Students at Alzahra University about Breast Self-Examination, Iran

Background: Breast cancer is the most common preventable cancer among women. One of the ways of prevention and early detection of breast cancer is breast self-examination (BSE). Thus, we decided to conduct a study about the knowledge and attitude toward BSE among the students of Alzahra University, Iran. Methods: This was a cross-sectional analytical study in which 135 female students aging 18-26 years were enrolled using stratified random sampling. Data was collected by valid and reliable questionnaires. Descriptive statistics and chi-square test were used to analyze the data. Results: While most students (45.9%) had an average level of knowledge about BSE, married students were significantly more knowledgeable (P = 0.007). The majority of students (68.1%), especially older, married students and those with a positive family history of breast cancer, had more positive attitude about BSE. The most popular way of gaining information among students was mass media. Students who gained information from university books had significantly more knowledge than others (P < 0.001). Subjects who obtained information from mass media had more positive attitude than others (P = 0.04). In addition, students with more knowledge had significantly more positive attitude (P < 0.001). Conclusion: The knowledge and attitude about BSE is less than satisfactory even among university students. The values would probably be even less among the general female population in Iran. Proper and more intense educational programs about BSE should be scheduled even in higher education institutions. Keywords: Knowledge, Attitude, Breast self examination, Students