THE LIGHT OF AMAZON ARCHITECT SEVERIANO MÁRIO PORTO

The use of passive techniques in architecture is welcome. A renowned Brazilian architect, Severiano Mário Porto, developed over 200 projects and became an icon of Brazilian modernism, specifically in the Amazon, working with this prerogative. This work aims to combine the analysis of the lighting quality in Severiano's projects, corroborating the recognized fame of the "Architect of the Amazon". The research procedures adopted were: documentary survey, selection of case studies, application of a monitoring protocol with photometric analysis and user consultation, and daylight computer simulation. In terms of daylighting, when applied the monitoring protocol on the current state of the building, the lighting values are not satisfactory according to Brazilian standards. As the view outside, the results showed medium and high quality. The questionnaires point to high levels of satisfaction. The computer simulations show the daylighting potential of the original design. There is clear evidence that the actual condition wastes the potential of the original design in terms of daylight use.

Performance evaluation of solar parabolic trough receiver using multiple twisted tapes with circular perforation and delta winglet

A parabolic trough collector (PTC) is one of the concentrating types of a solar collector working in the medium range of temperature from 100–400 °C, for this reason, the efficiency of the solar parabolic trough is less than other types of concentrating solar collector (Point focusing types) in terms of solar to thermal energy conversion, the improvement in efficiency is achieved by various passive heat augmentation techniques in the receiver tube. One of the promising passive techniques is twisted tape inserts used in the receiver due to its simplicity in design and the various possibility of geometric modification. This paper deals with the performance evaluation of the solar parabolic trough receiver system by using passive techniques in the receiver. The testing of the receiver of PTC was done by using multiple perforated twisted tapes with winglets having different perforation ratios ([Formula: see text]) of 0.05, 0.15, 0.25, twist ratios ([Formula: see text]) of 3, 4, 5 and wing depth ratios ([Formula: see text]) of 0.1, 0.2 and 0.3. The number of twisted tapes was fixed at 4. The examination was conducted for Reynolds numbers ([Formula: see text]) varying from 3000–21,000 using air as working fluid. The outcome shows that the use of perforation and winglet in twisted tapes augment the Nusselt number as compared to that of smooth twisted tapes. The maximum thermohydraulic performance ([Formula: see text]) of 2.40 is received by using multiple twisted tapes with perforation and winglet having [Formula: see text] = 0.3, [Formula: see text] = 3, and [Formula: see text] = 0.05 at the Re = 21,000. The correlations for Nusselt number ([Formula: see text]) and friction factor ([Formula: see text]) are also developed with ± 8.5% and ± 8.3% accuracy, respectively.

TRADITIONAL DWELLING OF M`ZAB VALLEY IN ALHERIA: THE POINT OF ADAPTATION TO THE ENVIREMENT

The article deals with the traditional dwellings in the UNESCO World Heritage ancient settlements (ksour) of M’zab Valley in Algerian desert. The Mozabite habitats are reflection of cultural and social values embodied in the architecture, with simple design in their forms deep in their indications, they are organized with a set of principles and rules known as customs that were inspired by religion and adapted to the environment. This latter helped to preserve Mozabite dwellings for more than a millennium. In this article the attention has been drawn to the dwelling’s design and distribution of its spaces according the activities and lifestyle of Mozabite community considering the arid environment needs. Sustainability strategies have significant presence in different levels of the dwelling appearing from the usage of passive techniques which depend on the principles of conservation energy and water, exploiting renewable resources and usage of local materials. These techniques are what make dwellings integrate completely within arid climate.

Effect of Nanofluids on the Enhancement of Boiling Heat Transfer: A Review

Boiling heat transfer can play a vital role in the two-phase flow applications. The analysis of the boiling hat transfer enhancement is of importance in such applications and the enhancement can be mostly conducted by using various active and passive techniques. One type of passive techniques is the enhancement of heat transfer by nanofluids. This article presents an extensive review on the effect of different nanofluids on the enhancement of heat transfer coefficient (HTC) and critical heat flux (CHF) for both pool as well as flow boiling. Nanoparticles addition to a working fluid is done arbitrarily to improve the thermophysical properties which in turn improves heat transfer rate. Numerous works have been done in the studies on nanofluid boiling. Among various nanoparticles, the most frequently used nanoparticles are Al2O3 and TiO2. In the case of binary nanoparticles, the most commonly used combination is Al2O3 and TiO2. After reviewing the relevant literatures, it is found that for pool boiling, the maximum HTC is increased to 138% for TiO2 nanoparticles and the maximum CHF is increased to 274.2% for MWCNTs. Conversely, in flow boiling the maximum HTC is increased to 126% for ZnO nanoparticles and the maximum CHF increased to as 100% for GO nanoparticles. In addition, when two or more nanoparticles in succession or binary nanofluids are used the CHF in pool boiling increased up to 100% for Al2O3 and TiO2 as well as the CHF in flow boiling increased up to 100% for Al2O3, ZnO, and Diamond. Though the information of the coefficient of heat transfer and the critical heat flux varied for different nanofluids and vary from experiment to experiment for each of the nanofluids. This variation happens because the coefficient of heat transfer and the critical heat flux in boiling is dependent upon several factors.

Experimental Investigation of Thermal Conductivity from Insulation Based on Rice Hulks: Guarded and Calibrated Hot Box Method

In developing countries, large quantities of agricultural residues associated with harvests are generated, given that agriculture is one of the most important economic activities. The valorization of these residues for the construction sector could contribute to the improvement of energy efficiency in buildings. Through passive techniques, the construction of insulating thermal-acoustics panels, blocks, and aggregate for reinforced concrete can improve the energy efficiency. In this study, an experiment was performed to measure thermal conductivity of the Agricultural-Thermal Insulation Panel (ATIP) based on rice hulks. These Agricultural-Thermal Insulation Panels were elaborated follow a standard process to compaction of the rice hulks to be employed as insulation material with a panel dimension of 200x200x34.5(mm3). A “Hot Box” configuration was used to obtain the thermal conductivity of the panels, using different temperature gradients between hot and cold chambers.

The Performance of the hairpin type U Shape Double pipe heat exchanger type under effect of using Passive and Active Techniques.

The process of improving and developing heat exchanger performance has received a lot of attention, and efforts are still being made by specialized researchers and engineers with a huge investigations to increase rate of heat transfer to lessen the volume size and price cost of the factories apparatus accordingly. In this experimental study, a suitable heat exchanger equipped with flow meters and thermocouples for measuring flow rates and temperatures was used with the U shape hairpin type exchanger. The bending and angle of curvature of the tubes causes vortex flow, which greatly aids to attractive the rate of heat transfer process and increase the performance, The effect of active and passive techniques with different positions of the U shape Exchanger like position (U shape and Inverse U shape ) as parallel coupling with tube liquid in series is investigated during this study. passive technique represented using the O ring fin type. and an active technique represented by the injection of an air bubble by a small compressor through a special air diffuser. The results show that the best application was with inverse U shape (∩) and the performance enhanced about (19.1%) in the case of active techniques while and (11.1%) with passive techniques and by applying both techniques together, the overall enhancement was (30.272%), So this study provides new visions for further studies.

A review study on the performance of a parabolic trough receiver using twisted tape inserts

Heat transfer in concentrating solar collectors like parabolic troughs has proven nowadays a very efficient method by using different passive techniques to increase the heat transfer rate. The use of passive techniques also increases the pumping power requirements to make the flow through the receiver. So, a number of researchers are working to find out the optimum performance conditions for parabolic trough receivers by using different types of inserts in flow paths. This paper presents a wide range of literature available for solar parabolic troughs in one place. Based on this extensive study, it is found that twisted tape inserts is a very wide field for investigation and the use of different shapes, pitch value, free space, and angle of twist tape are the parameters that can be considered for further studies to improve the performance of solar troughs. Also, various combinations of perforation and cuts on twisted tapes can be used to achieve enhanced performance.

CO2 and Radon Emissions as Precursors of Seismic Activity

This paper reports a review on the relationship between seismic activity and the emissions of CO2 and radon. Direct, indirect and sampling methods are mainly employed to measure CO2 flux and concentration in seismic areas. The accumulation chamber technique is the mostly used in the literature. Radon gas emission in seismic areas can be considered as a short-term pre-seismic precursor. The study and the measurement of radon gas activity prior to earthquakes can be performed through active techniques, with the use of high-precision active monitors and through passive techniques with the use of passive detectors. Several investigators report models to explain the anomalous behavior of in-earth fluid gasses prior to earthquakes. Models are described and discussed.

Numerical Investigation of The Effect of Finned Obstacle on Heat Transfer Characteristics in a Rectangular Channel

Nowadays, with the development of technology and science, heat transfer holds an important place in engineering applications. In industrial areas, heat increases give rise to overheating, causing system errors. Passive techniques are frequently used to prevent from such disruptions. In this work, fins which are passive techniques which provide heat transfer development with high efficiency and low cost were investigated. To improve heat transfer, finned structures should be well optimized. On the other hand, the designer can prevent mixing the incoming air with the heated air with a bad design, which may cause a negative effect rather than improve heat transfer. In this work, in contrast to previous works that is smooth tube and 0 degree rectangular finned tube, four fin structures were designed and flow and heat-transfer characteristics numerically analyzed. These are crescent finned tube, 20 degree symmetrical imperforated rectangular finned tube, 20 degree asymmetrical imperforated rectangular finned tube and 20 degree symmetrical perforated rectangular finned tube banks with six rows. In this investigation, the geometric parameters were not changed and their effects on flow and heat transfer properties in different Reynolds numbers on these models were examined. The results indicate that the symmetrical structure has better heat transferability and higher friction loss compared to the asymmetrical structure and the perforated fin is higher than imperforated fin but the overall performance is not always superior. Therefore, both symmetrical and perforated finned tube is designed and analyzed with the highest heat transfer potential, it is seen that in terms of heat transferability this model is better than other designs.