ANALISIS PENGARUH VARIASI KECEPATAN PUTARAN BLOWER TERHADAP KINERJA KOLEKTOR PANAS TENAGA SURYA PELAT TEMBAGA DENGAN SEKAT VERTIKAL

The availability of energy resources in the world increasingly diminish. More scientist is questing other renewable resources. The solar air heater is a tool that used energy by absorbing solar radiation then convert into heat energy. The study tried to have some variations to the speed of the air flow rate with spin 2500 rpm, 3000 rpm and 3500 rpm and give vertical partitions to it.The aim of giving vertical partitions is to know the influence to the heat transfer rate and the efficiency value of it. The result of this study is the speed variations of the blower take effect to the heat transfer rate. This is shown from the study data for 5 days, the average value of the heat of the system at 3500 rpm rotation is 341.6 Watts, 3000 rpm rotation value 305.7 Watt, and 2500 rpm rotation value 249.3 Watt. The average value of efficiency at 3500 rpm is 49.60%, 3000 rpm rotation is 43.22% and at 2500 rpm the value is 37.33%. The highest system heat is 535.79 Watt with the highest delta input and output temperature of 49.7 ℃. While the highest heat absorber is 1280.15 Watt with the highest light intensity, which is 140100 Lux. With a variety of rotation speeds blower and vertical partitions, this tool is capable of producing the highest efficiency of 67.95%, and the lowest is 24.85%.

Analytical meanders of selected systems for thermo-renovation of historical buildings

The article contains an analysis of selected systems for thermorenovation of vertical partitions in protected buildings. Historical buildings often require thermo-renovation, but in practice their "insulation" can be applied only internally on partitions without decorations. Internal thermorenovation methods can be classified according to heat exchange and moisture transport. For the purpose of this paper, the methods were analysed in terms of diffusion-open and diffusion-closed systems, and compared in a multi-variant aspect. The calculations were made assuming a wall with the moisture content up to 3%, a wall with the very high moisture content up to 11%, and for a wet wall with a constant inflow of water due to capillary action. They attempted to evaluate the effectiveness of various thermo-modernisation treatments in building partitions in the aspect of protection against permanent moisture growth, mould development and improvement of their overall heat protection, considering the 8-year time interval. Several different sets of materials were included in a multivariate analysis, as well as various scenarios of the possible effects of their use. The paper is summarised with conclusions regarding the effectiveness and risk related to the application of different internal methods of thermo-renovation of partitions.

One-Dimensional Model of Natural Convection in Differentially Heated Partitioned Enclosures With Conducting External Walls and Vertical Partitions

Natural convection in partitioned enclosures is extensively investigated due to its importance in many applications. Real enclosures have diffusive walls and partitions. A method has been developed to evaluate the global natural convection Nusselt number for a differentially heated (heated from sides) partitioned enclosure with walls and vertical partitions of finite thickness. A formula has been elaborated, giving the global Nusselt number as a function of the global Rayleigh number, global aspect ratio of the whole enclosure, and two other dimensionless parameters: the conductive thermal resistance ratio and the porosity. After validation of the method by comparison of our results with those from both the literature studies and the numerical simulation, a parametric study is carried out to show the influence of the dimensionless parameters. The method is a helpful tool for thermal engineers and scientists to design such a common system.