ANALYSIS OF ENERGY USE AND CONSERVATION : TWO TRANSPORT-RELATED CASE STUDIES

This thesis presents two case studies of energy analysis for transport-related applications. One is on energy consumption analysis of the production of road paving mixture and the other is on automobile fuel consumption in actual traffic. The first study was carried out on two asphalt premix plants, a continuous drum mix plant and a batch processing plant. It consists of two phases, the energy billing audit and field audit of the two plans. The billing audit involves a time series study of the plants' performance records and the main objective is to identify the energy consumption pattern of the production process. The field audit involves allocation of the total energy used by production process. It is found that there are two forms of process energy, electricity and diesel fuel, and 96% of the total energy used was diesel fuel which is mainly for drying and heating· of the raw aggregate mix. A series of experiments was carried out to study the moisture content of raw aggregates and the results show that a substantial saving in energy use can be achieved by reducing the moisture content of aggregate in the stockpiles. Other energy saving opportunities and comparisons of the two asphalt premix plants were also discussed in the study. In the automobile fuel consumption study, a travel survey which involves 115 drivers was carried out. Based on the survey data, which consist of 354 fuel-purchased cycles with a total of 11,638 trips, regression models on the specific automobile fuel consumption were derived. Fuel consumption analysis of three specific studies by trip characteristics, namely, road type, trip purpose and time period of trip generation, was carried out using the 354 cycle data. A factorization study on the variations of fuel consumption within each specific study was also carried out to determine the contributing factors. This is followed by a more thorough analysis on the overlapping effects of the above three specific studies which involves a three-dimensional decomposition of the 11,638 trip data. The results show that it is more fuel efficient to travel on expressway as the travelling speed is high and the trip distance is relatively long. Work and business trips which cover a relatively high distance portion of expressway are found to be more fuel economical than the personal trips which generally consist of many short distance trips in the town areas. The regression results also show that trip distance is an important determinant of automobile fuel consumption. This study is concluded with a statistical analysis on the energy effects of short distance trips.

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• NG TAI TEE