Theses & Dissertations

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Browsing Theses & Dissertations by Subject "Air conditioning"
  • Publication
    Improvement of air conditioning unit using a cost-effective sensible heat storage system
    ( 2019)
    Nursyazwani Abdul Aziz
    This project mainly investigates the performance of a split unit air conditioning system, with and without the integration of thermal energy storage (TES). In this work, the cost-effective tube-intank type of TES with the employment of sensible heat storage (SHS) material was constructed and integrated into a Split Unit AC system that used to cool a cabin container. From the integration, three configurations of cooling systems were established and therefore tested. It includes (1) Cabin container with conventional AC system, (2) Cabin container with water tank integration (ACTES) system, and (3) Cabin container integrated with insulated water tank (IACTES) system. From the experimental works, the energy consumption of all three tested systems was evaluated. Besides, the temperature distribution and relative humidity (RH) inside the cabin container were recorded and observed as to examine the effect of TES integration to the indoor comfort. From the experimental results, the temperature distribution (Teroom) is found to have improved with the integration of TES tank. IACTES integrated system has resulted the temperature difference (ΔT) to be as low as 0.81±0.01°C (5.1%) when compared to the set temperature of 16°C. Meanwhile, the average temperature for Conventional AC and ACTES integrated system are 2.96 ± 0.01° C and 2.84 ± 0.01°C, respectively. Besides, the cumulative electrical currents for the three configurations show that the integration of water tank as TES reduces the electricity usage by 5%, while the integration of well-insulated water tank saves up to 8% of the electricity consumption. For a single unit of a split unit AC system, with the cost of RM360, the total savings of the electrical consumption are estimated to be RM63 annually with payback period of 1 year and 318 days. Nevertheless, with referring to the total energy consumption for Malaysia in 2016, 8% of the reduction could save up to RM 2,323,926,776 a year. Therefore, the integrated system developed in this project is believed to set a benchmark for thermal studies, especially in AC and refrigerator design research and development works. Accordingly, the temperature distribution inside the cabin container were investigated through CFD modelling and simulation. The room model was developed matched the actual model as in experimental works. The temperature distribution of air temperature leaving the evaporator (from experimental works) are used as inlet values (Tinlet ) for Ansys simulation works. Comparisons on temperature distribution obtained from the simulation works to the data recorded from experimental works were done. In this work, new method for estimating heat losses is introduced. The average heat loss from the room (for each wall) is found to be 19.7, 19.0 and 17.0 W/m2, respectively. The values of heat flux obtained from the simulation are then used to estimate the COP of the system through the mathematical modelling method. From the estimation, it showed that the COP of a split unit AC system is improved with the integration of SHS tank as thermal storage system. In a nutshell, it can be concluded that the integration of water in tank as sensible heat storage is found to enhance the performance of the split unit AC system, with the SHS tank is best being insulated.
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