Effects of surface characteristics on condensation

• Main Author: Muhammad Dzafir Mohamed Zain Affandi
• Other Authors: Chan Weng Kong
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/75228
• Institution: Nanyang Technological University

This report consists of two parts: design and experiment. There were two things that were designed; the Housing Unit as well as the Experiment Rig. Both of these will be illustrated and explained in the upcoming chapters. The experiment section will detail the methodology, variables as well as the results that were obtained through the experiments conducted. This report will illustrate the thinking process, the explanation of the design of the Housing Unit and Experiment Rig and the reasoning along with calculations to support the use of certain design specifications for the following parts; Peltier element, battery and solar panel. With the design specifications, parts can be sourced to fit the requirements and to be utilised in the Housing Unit and Experiment Rig. The completed Housing Unit was able to support a 150 W rated solar panel with a 100 Ah 12 V battery and a 12 V 60 W rated Peltier Element. To add to that, a compatible Maximum Power Point Track (MPPT) solar charge controller was incorporated into the design so that the solar panel will be more efficient in harnessing solar energy and a data logger is attached to track the power harnessed and consumed daily.This report will also investigate the feasibility of harnessing water from air by studying the effects of surface characteristics on condensation. This is the experiment part of this report. As the essence of harnessing water from air revolves around condensing the water vapour, it would be imperative to do so in the most effective manner. The surface characteristics will vary in roughness, application of a hydrophobic inducing spray, the inclination angle and its orientation (applies to all but when inclination angle is 90⁰). Four types of condensing plates, three inclination angles and two surface orientations were used to obtain data for comparison of condensation to find out which was the best in getting the most amount of condensation. The condensing plates used were either unaltered (Type A), roughened only (Type B), sprayed only (Type C) or roughened and sprayed (Type D). The angles used were 90⁰, 60⁰, 40⁰, 25⁰or 10⁰. The surface orientation was either facing up or facing down and this applied to all inclination angles except for when it was 90⁰. All the experiments were conducted in an environment that was exposed to minimal sunlight (i.e. a dark room) and the humidity was kept between 85-95%. This was done to ensure maximum water condensation that was well within the range of relative humidity experienced in Singapore from dusk till dawn. It was found that a roughened surface (Type B) facing downwards (unturned) at an inclination angle of 60⁰ yielded the most amount of water (2.2 ml) through condensation over 3 hours. The trend that was observed was that roughened surfaces that were turned downwards tended to do better than roughened surfaces that were facing upwards. Roughened surfaces facing downwards harnessed 72% more water than those facing downwards. Also, it was found that spraying Rust-Oleum’s NeverWet negatively affected the condensation rate of the surfaces. For any orientation and inclination angle, the water collected from condensation of the sprayed surface was consistently worse than the non-sprayed counterpart, except for when the angle was 25⁰ and 60⁰ when the surfaces were facing upwards which may have just been an anomaly.