No abstract

Thermoelectric cooling (TEC), in particular, can be combined with a heat sink for local cooling, but they can also be integrated into electronic chips for point-to-point cooling. The study aims to develop a dynamic model of a cooling system integrated with TEC for glass window. The main target of this study is to develop a dynamic model of a cooling system integrated with TEC. The black box modelling approach in producing a mathematical model was selected based on the ARMAX and ARX model that corresponds to the actual dynamic state of the cooling system. The best model was finalized based on the best match on curve patterns when comparing the real and estimated models using the system identification tools in MATLAB, and also having the least error. The accuracy of the models was compared and analysed. The results showed that the 4th order of the ARMAX model produced a higher best fitting and standard deviation values of 80.23% and 0.027592 compared to the 4th order of the ARX model of 78.14% and 0.030769 respectively. This system accuracy is almost within the acceptable range for most error calculations in the validation method. Yet, this cooling system integrated with TEC is found more suitable for the 4th order of the ARMAX model when compared to the ARX model due to the noise parameter in the ARMAX model. Nevertheless, the noise order in this system is not dominant, therefore, whenever the noise order of the system in the ARMAX model is high than the second structure (nb), the number of errors is also high. In addition, the ARMAX model is found incapable of achieving the highest fitting due to the losses from the dynamic environment and losses from the TEC itself. Still, the use of this black box model used in this study is a significant variation where system parameters can be identified even offline.

The automotive industry has rapidly introduced pollution-free vehicles such as Electric Vehicle (EV). The development and improvement of the EV to replace the conventional vehicle become crucial to obtain the customer satisfaction and high technology achievements. The main systems in EV that are improvise to be switch from the conventional engine with a fuel source to an electric type drive system, include the electric motor and the energy/power storage called battery. There are several types of electric motors that suitable for EV and the best solution was Brushless Direct Current (BLDC) motor in terms of power, speed, torque and low maintenance. Meanwhile, the fuel source replacement is the electrical energy/power storage such as batteries. The aims were to study the best Energy Storage System (ESS) in EV which leads to introducing Battery Energy Storage System (BESS), but the drawbacks of the system give the opportunity improvement, in replacement using Supercapacitor Energy storage System (SESS) and Hybrid Energy Storage System (HESS). SESS is a reliable source, but the stand-alone Supercapacitor also has a minimum operation time. With several adjustments in the energy management control strategy, the discharge rate of energy from a supercapacitor can be minimized to prolong its operation.

Refrigerator is the key component to keep the medicine and biological sample in the hospital. The domestic refrigerator has the problem of larger size and heavier weight since to the compact system like condenser, compressor, evaporator and expansion valve are assemble and using in the refrigerator. This project focused on design of temperature control of the portable thermoelectric refrigerator for medical purpose. Thermoelectric refrigerator is using the direct cooling method through thermoelectric module. Thermoelectric refrigerator has several advantages such as smaller size, lighter and silent when operated. Since maintain a constant temperature for the storage of medical product is important, a specific refrigerator is needed to ensure the medicine is stored in desired temperature. This project is to design and develop an adaptive control system which can perform a good temperature control for the thermoelectric refrigerator. The second order model is applied to design adaptive Proportional-Derivative (PD) controller. The selected controller is the adaptive PD controller because the performance of response shows 0.42°C of less steady state error and 0.21°C of lower undershoot. The adaptive PD control system designed able to let the refrigerator operate in different operating condition without influence the performance of the refrigerator.

Kajian simulatif telah dijalankan mengenai penggunaan teknik korelasi–silang untuk ultrasonik transmisi tomografi satah berganda. Teknik ini digunakan untuk membandingkan isyarat dari setiap satah yang masing–masing dinamakan satah–bawah dan satah–atas. Pemisahan jarak antara kedua–dua satah adalah tetap. Hasil dari perbandingan isyarat satah berganda, digabungkan dengan jarak pemisahan yang telah diketahui termasuk kelajuan sistem memproses maklumat, boleh digunakan untuk menganggarkan kelajuan aliran di dalam paip pemprosesan yang hendak diteliti. Penggabungan Ultrasonik Transmisi Tomografi (UTT) dengan teknik pengukuran korelasi–silang dapat memberikan maklumat yang lebih lanjut mengenai aliran jika dibandingkan dengan sistem UTT bersatah tunggal. Diskusi dalam artikel ini lebih memfokuskan kepada nilai min setiap gambar dan pekali korelasi 2D yang akan digunakan untuk mengkorelasikan gambar tomogram antara satah–bawah dan satah–atas. Prinsip pengukuran kelajuan pergerakan gas didalam keadaan gas dan cecair yg bergelembung berdasarkan pada korelasi–silang antara kedua–dua satah juga dijelaskan. Keputusan awal eksperimen menggambarkan kesesuaian kaedah yang dibentangkan di sini. Kata kunci: Korelasi–silang; corak beku; korelasi min; simulasi satah berganda; tomografi transmisi ultrasonik Simulative studies are done on the use of cross–correlation technique based on a dual–plane ultrasonic transmission tomography for liquid and gas two–phase flow measurement. This technique is used to correlate the signals from each sensing area namely downstream plane and upstream plane. Separation distance between both sensing areas is fixed. The result from cross correlating the dual–plane signals, combined with the known separation distance and the system’s acquisition rate is used to estimate the velocity of the flow inside the investigated process column. Combining Ultrasonic Transmission Tomography (UTT) with the cross–correlation flow measurement technique can provide more information on the flow than a single–plane UTT system. This paper focuses on the mean value of the images and the 2D correlation coefficient that is used to cross–correlate the tomogram images between the downstream and upstream plane of the simulated dual–plane ultrasonic transmission tomography system. The principle of measurement for local gas velocity distribution in a bubbly gas/liquid pipe flow based on crosscorrelation of two plane images is also described. Initial experimental results illustrate the feasibility of the method presented here. Key words: Cross–correlation; frozen pattern; mean correlation; dual–plane simulation; ultrasonic transmission tomography