Journal of Sustainable Energy

5

Authors: KLADISIOS P., SAGIA A.

Supercritical water gasification is a promising and environmentally friendly biomass conversion method. Compared to conventional gasification, it is capable of handling biomass with high moisture and displays higher conversion efficiency and decreased tar formation. Through supercritical gasification, organic feedstock in the presence of supercritical water is converted into a mixture of H2, CO2, CO, CH4 and traces of other gases over shorts periods of time. The composition and yield of the final gas mixture depends highly on reaction temperature, feed concentration and nature of catalyst in use. Reaction pressure and residence time play a less important role. Despite being appealing for the production of hydrogen from an inexpensive source, hydrothermal gasification suffers from decisive technical challenges, with corrosion and efficiency being the most critical.

6

Authors: EL FARRI. H, BOUACHRI. M, FAHOUME. M

In this paper, the performance of CIS Based solar cells was investigated, using a simulation program named SCAPS-1D Software (Solar Cells Capacitance Simulator). CIS cell structure is based on Cu(In, Ga), (Se,S)2; which is a semiconductor compound as an absorber layer; un-doped Zinc Oxyd (i) ZnO as a window layer, and Sulfide Cadmium as a Buffer layer, with an efficiency of ƞ=17%. We studied the influence of different layers’ thickness and their defect densities, working temperature and absorber carrier density on the CIS based solar cells. The photovoltaic parameters have been calculated, and we have obtained the optimal values of every constraint cited above. As a result, we obtained a new high efficiency value of 19.71%, under air mass (AM) 1.5 and 100 mW/cm2 illumination and the area of this device was 0.15 cm2 [8].

8

Authors: TIRUNEH A.T., DEBESSAI T., NKAMBULE S., BWEMBYA G.

The performance of compound parabolic solar concentrators (CPC) is extended through the provision of additional external reflectors that increased the angle of acceptance and hence achieve concentration for longer part of the day. The modified setup increased the angle of acceptance by over 70% while achieving comparatively close concentration ratio ranging between 90-100% of the maximum attainable. For construction of geometry of the reflector profile, an approach involving coordinate transformation has been used. Satisfactory performance of the solar concentrator has been observed for applications involving grey water treatment, production of struvite and drying of fecal matter from urine diversion dry toilets and compost.

10

Authors: FELEA. I., MOLDOVAN V., BUNDA. S., LIBOR L., ILE I.

Knowing the level of energy efficiency is essential for substantiating investment decisions, operation and maintenance of energy consuming equipment and machines. Urban public transport is an important consumer of energy and, at the same time, an important source of pollution of the urban environment with greenhouse gases and micro particles. The present paper is aimed to identify the level of the energy performance of a public transport car fleet, having buses equipped with Diesel engines. The analysis methodology and the mathematical model used are applicable to other similar structures. The obtained results are valid for the analyzed car fleet, highlighting the values of the energy performance indicators, on the whole, by bus categories and for each bus from the park component. Based on the results obtained within the energy audit, comparisons are made for the level of energy performance with similar consumers, and feasible measures to improve energy efficiency are identified.