Search

Abstract: The need for air-conditioning in the Mediterranean countries is higher and higher due to the effects of global warming. This paper deals with an investigation of a high performance, solar-driven air-conditioning system, the project entitled “Mediterranean AIRCOND”, is funded by the European Community under the „Community Activities in the Field of the specific program for RTD and demonstration on “Energy, Environment and Sustainable Development”. “AIRCOND” aims to study and investigate performances of advanced solar driven air conditioning system; the field system is composed of three sub systems: the heating loop, the ejector cycle and the cold storage-air handling units: The heating loop is composed of a solar array of 60 square meters evacuated tube solar collectors; installed at a tilt angle of 45o and facing to south, a 3000 L tank which is used as hot water storage in order to cover the required energy by the ejector cycle. The cold water produced by the ejector cycle will be then transferred in a 900L cold storage tank filled with 800L micro-encapsulated phase change material (MEPCM) for cold storage. It is designed to meet the dynamic cooling load. The ejector was tested at the School of the Built Environment in the University of Nottingham in UK and then transferred to Tunisia for field evaluation. Many previous theory studies have been fulfilled on this technology but never been performed experimentally at this level. This paper presents the research effort made and the experience gained during the implementation of the whole system: Different operation strategies were followed during more than one year to make the ejector cycle functional. The whole procedure has turned out to be very difficult; it was particularly difficult to obtain a deep vacuum and to ensure a good vacuum quality; this is a necessary working condition for the ejector cycle. Successful ejector tests were obtained during 8min, 15min and 40min, after many investigations; later experiments led to 3hours of continuous working. Results are very promising; the installation is still under tests in order to obtain a whole day permanent working of the ejector cycle and so of all the solar installation. [Copyright &y& Elsevier]

Abstract: The availability of solar radiation in phase with the seasonal as well as hourly cooling load profiles in most of the office buildings in the Mediterranean region, in addition to the large share of primary energy consumed for air- conditioning applications in office buildings create a high motivation for the utilization of solar cooling technology for such type of buildings. A solar heating and cooling system for an office building in Italy has been designed, installed and monitored within the framework of the EC co-funded project SOLERA aiming at developing highly integrated solar thermal heating and cooling system that is able to achieve a high solar fraction both for the heating and cooling seasons. The analysis of the system performance during 2011 is presented in this paper, with main focus on electricity consumption during summer. The analysis has been carried out according to the monitoring procedure developed within the frame of the IEA SHC Task 38. [Copyright &y& Elsevier]

Abstract: Fenestration has always been regarded as the weak element in the building envelope due to its role in determining of the energy balance of a building. At the same time, cooling performance is becoming a significant parameter for evaluating the energy performance of buildings in Europe. Due to the plethora of window products with advanced properties currently existing on the market, it is not always easy for engineers to select the optimum solution. In this paper, the cooling performance of windows in the warmest part of Europe is evaluated with regard to their geometrical, thermophysical and optical characteristics, as well as their shading provisions. The analysis shows that the contribution of the windows in determining cooling loads is maximized when their solar transmittance is high and their thermal transmittance is low. Moreover, in the Mediterranean regions the increased thermal efficiency of transparent elements in buildings with controlled ventilation, such as offices, prohibits the dissipation of heat toward the ambient environment and ultimately result in higher cooling energy loads. [Copyright &y& Elsevier]

Abstract: Thermal, environment and economic impact of Trombe wall system for residential building in Mediterranean region will be studied in this paper. Moreover, optimum size of this system will be determined by using Life Cycle Cost (LCC) criterion. This will lead to develop an approach for designing the most economic residential building in Mediterranean region. Hour-by-hour energy computer simulations were run with TRNSYS program to analyze the performance of Trombe wall. Then, a complete economical equations of LCC have been built and optimized for variable Trombe wall area ratio as a function of economic and thermal parameters. The optimum Trombe wall area ratio from thermal and economical point of view is 37%. This optimum ratio has reduced LCC by 2.4%. Moreover, about 445kg CO2 will be reduced annually. [Copyright &y& Elsevier]

Abstract: In this paper, the seismic performance of reinforced concrete exterior wide beam–column connections with shallow spandrel beams lightly reinforced for torsion and moderate levels of gravity loads was investigated experimentally. The study focuses on existing frames designed and detailed according to construction practices used over ten years ago in the moderate-seismicity Mediterranean area. The results can be useful for assessing the seismic vulnerability of older structures and orienting seismic retrofit alternatives. Two 3/5 scale test models representative of exterior sub-assemblages in a prototype six-story building were subjected to gravity-load levels typical of those acting during an earthquake, and quasi-static cyclic lateral loads until failure. The performance was studied in terms of strength, displacement, ductility and energy dissipation capacity. The data are analyzed in conjunction with the results of previous tests. The specimens exhibited a “strong column–weak beam” type of flexural yielding mechanism. The average drift ratios at first yielding of the wide beam longitudinal reinforcement, , and at failure, , were 2.2% and 4.5% respectively; the displacement ductility ratio was approximately 2.2. Comparison to similar connections without added gravity loads showed that moderate levels of gravity loading increased by about 40%, and decreased by a similar percentage the value of and the energy dissipated in each half cycle of displacement expressed in terms of an equivalent viscous damping ratio. Finally, two approaches for estimating the wide-beam flexural capacity are examined. [Copyright &y& Elsevier]