NUST Institutions Library Catalogue Search for 'an:"124968"'

Performance Enhancement of a Shell and Tube Heat Exchanger by Introducing Novel Baffle Design /

By Sultan, Badar . . 61p. , This research involves the investigation of the performance of a Shell and Tube Heat Exchanger. The study is focused on examining the existing baffle designs. It also involves the design of changing the baffle to improve thermal performance. The existing model of the thermal performance of the baffle is studied and discussed. Limitations are highlighted and based on those; the changed baffle is proposed. Meshing of the heat exchanger is performed to observe the theoretical results. After that experiments on the baffle are also performed. Experiments involve observing the results of the temperature variation as well as pressure drops. It was observed that the conventional baffle did not perform as per desire. Main issues were that the copper tubing was initially painted, thus reducing performance. The paint was removed and the results slightly improved. There is also the issue that the heat exchanger is parallel flow which is a lower performing type. We can change the configuration to a counter flow to improve the performance. For future works, it is suggested that the baffle design may be further improved with a pressurized heat exchanger test bench as well as counter flow heat exchanger. 30cm.

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Hybrid AI-Driven Probabilistic Modeling of Window Operations and Thermal Comfort: A Multi-Variable Approach for Residential Environments /

By Janjua, Osama Maqsood . . 109p. , Occupant window interactions is a critical component in optimizing energy consumption and indoor environmental quality. Understanding the influence of environmental and behavioral factors on window state decisions remains a significant challenge in building management systems. We present an AI integrated probabilistic model to assess thermal comfort and predict the probability of the occupant opening or closing the window. The data was acquired from an open-source platform that provided yearly university dormitory window interactions. Bayesian networks and logistic regression models were applied to predict the window-opening behavior of the occupants. An average accuracy of 92% for Bayesian and 94% for Logistic regression were obtained. The results were further enhanced by combining these models through weighted methods, with weights extrapolated through generative recursive iterations generating an average accuracy of 95% and AUC of 98%. The proposed hybrid approach significantly improves over existing predictive models in thermal comfort and window state prediction. 30cm.

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Design, Development and Performance Analysis of a Novel Double Slope Solar Still /

By Touqeer, Engr.Haziq . . 74p. , Regions across the world lack the availability of clean and freshwater. Traditional solar still (s) have been made, however their current low output remains a barrier. This study presents a design that incorporates mild steel fins of varied geometries to enhance the productivity of a square stepped solar still. Under real world conditions, the three fin geometries : 0.5 inch cylindrical, 1 inch cylindrical and tree shaped fins, all with a maximum height of 2 inches, were fabricated from mild steel and were analyzed for thermal performance potential. When compared to a baseline which was finless, the experimental results demonstrated significant efficiency enhancements, with average daily efficiency rising from a baseline of 23.27 % to 26.1 %, 27.8 %, 29.23 % for the 0.5 inch cylindrical, 1 inch cylindrical and tree shaped fins respectively. Furthermore, distilled water quality, from all the enhanced configurations, consistently met WHO potable water standards. In conclusion, the integration of mild steel fins proves to be a highly effective and economically viable method for significantly augmenting heat transfer, evaporation rates, and overall productivity in stepped solar still (s). This design presents a promising approach, for advancing sustainable desalination technology in remote and water scarce communities. 30cm.

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