Mohd Yusof Taib creator author. text abstract or summary my 2018 2018 monographic eng

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xviii, 191 pages : illustrations (some color), charts ; 30 cm. + 1 CD-ROM Ground heat exchanger is a technology which utilises ground temperature in producing cooling and heating effects. It is widely implemented in Northern America and European countries. Both experimental and simulation methods had been used to analyse the system’s performance. However, the main challenge in previous studies is the time consumed in conducting the experiments which could take one year duration. This is because ground heat exchanger performance is dependent on the ground temperature, ground thermal properties and ambient temperature which are further dependent on time throughout the year. Therefore, the main objective of this study is to analyse the performance of the ground heat exchanger using experimental simulator methods to eliminate the time dependence factor for equatorial region where, in this research, the Malaysian climate is chosen as case study. This study started with ground potential analysis, followed by ground temperature variation study and ended with performance analysis of the ground heat exchanger. Experimental and simulation methods were used to analyse ground temperature variation and performance analysis. The measurement of ground temperature was conducted for depth up to 1.5 m. Meanwhile, simulation of the ground temperature was conducted for depth up to 20 m with thermal diffusivity ranging from 0.04 to 0.10 m2/day in one year. In the ground heat exchanger performance study, experimental simulator unit and mathematical model simulation methods were used. The simulator was designed with 85% effectiveness for better thermal performance. The experiments were conducted for input temperatures of 31 to 35 °C, ground temperature of 23 to 26 °C, and 0.03 to 0.07 kg/s of mass flowrate. Meanwhile, the simulation study was conducted with three different pipe diameters namely ID80, ID100 and ID125. Input parameter of inlet temperature from 31 to 35 °C, ground temperature at particular depth and flowrate of 0.02 to 0.2 kg/s were preferred. The results show that the constant ground temperature is 27 °C, which is considered as the ground being able to produce cooling effects along the year. Thus, the ground heat exchanger has potential to be implemented in equatorial climate regions. In the experiment of ground heat exchanger simulator, fluid temperature inside the pipe reduces as the length of the pipe increases. The highest temperature reduction of 9.6 °C occurred at ground temperature setting of 23 °C, inlet temperature of 35 °C, and mass flowrate of 0.03 kg/s. The highest effectiveness of the simulator was obtained as 80.8%. Meanwhile, simulation in ground temperature shows that the ground temperature varies sinusoidally throughout the year. The temperature amplitude gets attenuated as the depth increased from the surface until constant temperature which occurred at depth of approximately 6 m with small amplitude of 0.7 °C. The simulation of mathematical model of the ground heat exchanger indicated that the fluid temperature reduced as the length of the pipe increased up to 25 m. The maximum reduction obtained was 11.8 °C for air inlet temperature of 35 °C, mass flowrate of 0.02 kg/s and ID125, which equalled to the effectiveness of 98%. There was an effect of pipe internal diameter from ID125 to ID80 at the same parameter of mass flowrate, ground temperature and inlet temperature with 4.7% of outlet temperature rise. The overall average temperature difference between experimental and simulation is 0.7 °C or 2.7% which showed a good agreement between each other. As conclusion, the experimental ground heat exchanger simulator operated well and the simulator can be used as performance study of ground heat exchanger for result acceleration at a wide range of working conditions. specialized Mohd Yusof Taib Faculty of Mechanical Engineering Thesis (Doctor of Philosophy) -- University Malaysia Pahang – 2018 Includes bibliographical references Faculty of Mechanical Engineering Dissertations Universities and colleges Disertations Theses THE0005285(Local) UMP 190225 20251117113409.0 vtls000105503 eng