Search results for: thermal efficiency.

Authors: Zakariya B. H., Idris M. I., Jungudo M. A.

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High energy consumptions of urban settlements in Nigeria are escalating due to strong population growth and migration as a result of crises. The demand for lighting, heating, ventilation and air conditioning (LHVAC) is becoming higher. Conversely, there is a poor electricity supply to both rural and urban settlement in Nigeria. Generators were mostly used in Nigeria as a source of energy for LHVAC. Energy efficiency can be defined as any measure taken to reduce the amount of energy consumed for heating ventilation and air-conditioning (HVAC), and house hold appliances like computers, stoves, refrigerators, televisions etc. The aim of the study was to minimize energy consumption in building through the integration of energy efficiency and renewable energy in building sector. Some of the energy efficient buildings within the study area were identified, the study covers there major cities of Nigeria namely, Abuja, Kaduna and Lagos city. The cost of investment on the energy efficiency and renewable energy was determined and compared with other fossil energy source for conventional building. Findings revealed that the low energy and energy efficient buildings in Nigeria are cheaper than the conventional ones. Based on the finding of the research, construction stake holders are strongly encouraged to abandon the conventional buildings and consider energy efficiency and renewable energy in buildings.

Keywords: energy, efficiency, LHVAC, sustainable development

Procedia PDF Downloads 563

Authors: Fadwa Haraka, Ahmad Elouatouati, Mourad Taha Janan

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In this study, we propose a neural network based method in order to calculate the heat source temperature of isotropic plate with lower surface forced cooling. To validate the proposed model, the heat source temperatures values will be compared to the analytical method -variables separation- and finite element model. The mathematical simulation is done through 3D numerical simulation by COMSOL software considering three different materials: Aluminum, Copper, and Graphite. The proposed method will lead to a formulation of the heat source temperature based on the thermal and geometric properties of the base plate.

Keywords: thermal model, thermal resistance, finite element simulation, neural network

Procedia PDF Downloads 342

Authors: Muhammad Abid

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Utilization of renewable energy resources for energy conservation, pollution prevention, resource efficiency and systems integration is very important for sustainable development. In this study, we perform energy and exergy analyses of a wind turbine, located on the roof of Mechanical Engineering Department, King Saud University, and Riyadh, Saudi Arabia. The turbine is part of a hybrid photovoltaic (PV)-wind system with hydrogen storage. The power output from this turbine varies between 1.5 and 5.5 kW with a rated wind speed of 12 m/s and a cut-in wind speed of 2.4 m/s. We utilize a wide range of experimental data in the analysis and assessment. We determine energy and exergy efficiencies. The energy efficiency changes between 0% to 45% while the exergy efficiency varies between 0% and 31.3%. We also determined some of the exergoeconomic parameters that are the ratios of energy and exergy loss rates to the capital cost (R en and R ex), respectively. (R en) changes between 0.96% and 59.03% for different values of velocity while R ex has a maximum value of 53.62% for the highest wind speed.

Keywords: exergy, efficiency, performance evaluation, wind energy

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Authors: Vasilios Kanellopoulos

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The present paper examines the effect of innovation efficiency on the production of new knowledge from a firm level perspective. It resorts to the Greek version of community innovation survey (CIS 2012-2014 microdata) and employs 1274 firms of the manufacturing, which constitutes the main sector of examination. It assumes a knowledge production function (KPF) and finds that R&D spillovers related to the expenditures on innovation activities, internal R&D, external R&D, skilled labor, and the expenditures in the acquisition of machinery have a positive and significant effect on the production of new knowledge when OLS techniques are applied. However, innovation efficiency comes from a Banker and Morey (1986) data envelopment analysis (DEA) with categorical variables has a statistically insignificant impact on the production of new knowledge measured by firm’s turnover.

Keywords: firms, innovation efficiency, production of new knowledge, R&D spillovers

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Authors: Lusine S. Stepanyan, Elina V. Asriyan.

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It is known, that the efficiency of management depend on individual characteristics of manager. In case, was shown the role of personal position in the efficiency of management. Current research is aimed at reveal psychological and psychophysiological basis efficiency of management and finding ways of increasing the productivity of management that is most essential and topical problems of modern society. To understand the investigated phenomenon it was applied a complex approach. The Eysenk questionnaire was used for determining the level of aggression, frustration, anxiety and rigidity. The test of egocentric associations was used for determining the level of egocentrism. The test of COS (communicativeness and organizational skills) was used for diagnosing the level of communicativeness. The integral index of job satisfaction was used for diagnosis the efficiency of management activity. Then, the relationship between the above mentioned mental state, communicativeness, self-esteem, job satisfaction, locus of control, and egocentrism was investigated. The obtained results have shown the positive correlation between the egocentrism and frustration, anxiety and also the negative correlation with job satisfaction and communicativeness. Intergroup analyses has revealed the significant differences by communicativeness and the internality’ level. The revealed results can be used for diagnosis of efficiency of management.

Keywords: egocentrism, locus control, mental state, job satisfaction, professional activity

Procedia PDF Downloads 354

Authors: Paula Marín, Mohammad Saffari, Alvaro de Gracia, Luisa F. Cabeza, Svetlana Ushak

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Climate control represents an important issue when referring to energy consumption of buildings and associated expenses, both in installation or operation periods. The climate control of a building relies on several factors. Among them, localization, orientation, architectural elements, sources of energy used, are considered. In order to study the thermal behaviour of a building set up, the present study proposes the use of energy simulation program Energy Plus. In recent years, energy simulation programs have become important tools for evaluation of thermal/energy performance of buildings and facilities. Besides, the need to find new forms of passive conditioning in buildings for energy saving is a critical component. The use of phase change materials (PCMs) for heat storage applications has grown in importance due to its high efficiency. Therefore, the climatic conditions of Northern Chile: high solar radiation and extreme temperature fluctuations ranging from -10°C to 30°C (Calama city), low index of cloudy days during the year are appropriate to take advantage of solar energy and use passive systems in buildings. Also, the extensive mining activities in northern Chile encourage the use of large numbers of containers to harbour workers during shifts. These containers are constructed with lightweight construction systems, requiring heating during night and cooling during day, increasing the HVAC electricity consumption. The use of PCM can improve thermal comfort and reduce the energy consumption. The objective of this study was to evaluate the thermal and energy performance of containers of 2.5×2.5×2.5 m3, located in four cities of Chile: Antofagasta, Calama, Santiago, and Concepción. Lightweight envelopes, typically used in these building prototypes, were evaluated considering a container without PCM inclusion as the reference building and another container with PCM-enhanced envelopes as a test case, both of which have a door and a window in the same wall, orientated in two directions: North and South. To see the thermal response of these containers in different seasons, the simulations were performed considering a period of one year. The results show that higher energy savings for the four cities studied are obtained when the distribution of door and window in the container is in the north direction because of higher solar radiation incidence. The comparison of HVAC consumption and energy savings in % for north direction of door and window are summarised. Simulation results show that in the city of Antofagasta 47% of heating energy could be saved and in the cities of Calama and Concepción the biggest savings in terms of cooling could be achieved since PCM reduces almost all the cooling demand. Currently, based on simulation results, four containers have been constructed and sized with the same structural characteristics carried out in simulations, that are, containers with/without PCM, with door and window in one wall. Two of these containers will be placed in Antofagasta and two containers in a copper mine near to Calama, all of them will be monitored for a period of one year. The simulation results will be validated with experimental measurements and will be reported in the future.

Keywords: energy saving, lightweight construction, PCM, simulation

Procedia PDF Downloads 267

Authors: Robert Wimmer, Soeren Eikemeier, Michael Berger, Anita Preisler

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A relatively large percentage of energy and resource consumption occurs in the building sector. This concerns the production of building materials, the construction of buildings and also the energy consumption during the use phase. Therefore, the overall objective of this EU LIFE project “LIFE Cycle Habitation” (LIFE13 ENV/AT/000741) is to demonstrate innovative building concepts that significantly reduce CO₂emissions, mitigate climate change and contain a minimum of grey energy over their entire life cycle. The project is being realised with the contribution of the LIFE financial instrument of the European Union. The ultimate goal is to design and build prototypes for carbon-neutral and “LIFE cycle”-oriented residential buildings and make energy-efficient settlements the standard of tomorrow in line with the EU 2020 objectives. To this end, a resource and energy-efficient building compound is being built in Böheimkirchen, Lower Austria, which includes 6 living units and a community area as well as 2 single family houses with a total usable floor surface of approximately 740 m². Different innovative straw bale construction types (load bearing and pre-fabricated non loadbearing modules) together with a highly innovative energy-supply system, which is based on the maximum use of thermal energy for thermal energy services, are going to be implemented. Therefore only renewable resources and alternative energies are used to generate thermal as well as electrical energy. This includes the use of solar energy for space heating, hot water and household appliances like dishwasher or washing machine, but also a cooking place for the community area operated with thermal oil as heat transfer medium on a higher temperature level. Solar collectors in combination with a biomass cogeneration unit and photovoltaic panels are used to provide thermal and electric energy for the living units according to the seasonal demand. The building concepts are optimised by support of dynamic simulations. A particular focus is on the production and use of modular prefabricated components and building parts made of regionally available, highly energy-efficient, CO₂-storing renewable materials like straw bales. The building components will be produced in collaboration by local SMEs that are organised in an efficient way. The whole building process and results are monitored and prepared for knowledge transfer and dissemination including a trial living in the residential units to test and monitor the energy supply system and to involve stakeholders into evaluation and dissemination of the applied technologies and building concepts. The realised building concepts should then be used as templates for a further modular extension of the settlement in a second phase.

Keywords: energy-efficiency, green architecture, renewable resources, sustainable building

Procedia PDF Downloads 139

Authors: Bahadır Aydın

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Being one of the most important elements of social evolution, energy has a vital role for a sustainable economy and development. Energy has great importance to level up the welfare. By this importance, countries having rich resources can apply energy as an political instrument. While needs of energy is increasing, sources to respond this need is very limited. Therefore, countries seek for alternative resources to meet their needs. Renewable energy sources have firstly taken into consideration. Being clean and belonging to countries own sources, renewable energy resources have been widely applied during the last decades. However, renewable energy cannot meet all the expectation of energy needs. In this respect, energy efficiency can be seen as an alternative. Energy efficiency can minimize energy consumption without degrading standard of living, lessening quality of products and without increasing energy bills. In this article, energy resources, SWOT analysis of renewable sources, and energy efficiency topics are mainly discussed.

Keywords: energy efficiency, renewable energy, energy regulations, oil, international relations

Procedia PDF Downloads 447

Authors: Sadia Siddiqa, Z. Khan, M. A. Hossain

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In this article, the effect of thermal radiation on mixed convection boundary layer flow of a viscous fluid along a highly heated vertical flat plate is considered with varying density and volumetric expansion coefficient. The density of the fluid is assumed to vary exponentially with temperature, however; volumetric expansion coefficient depends linearly on temperature. Boundary layer equations are transformed into convenient form by introducing primitive variable formulations. Solutions of transformed system of equations are obtained numerically through implicit finite difference method along with Gaussian elimination technique. Results are discussed in view of various parameters, like thermal radiation parameter, volumetric expansion parameter and density variation parameter on the wall shear stress and heat transfer rate. It is concluded from the present investigation that increase in volumetric expansion parameter decreases wall shear stress and enhances heat transfer rate.

Keywords: thermal radiation, mixed convection, variable density, variable volumetric expansion coefficient

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Authors: Jelvin Tom Sebastian, Vinod Yeldho Baby

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In space, electronic devices are constantly attacked with radiation, which causes certain parts to fail or behave in unpredictable ways. To advance the thermal controllability for microsatellites, we need a new approach and thermal control system that is smaller than that on conventional satellites and that demand no electric power. Heat exchange inside the microsatellites is not that easy as conventional satellites due to the smaller size. With slight mass gain and no electric power, accommodating heat using phase change materials (PCMs) is a strong candidate for solving micro satellites' thermal difficulty. In other words, PCMs can absorb or produce heat in the form of latent heat, changing their phase and minimalizing the temperature fluctuation around the phase change point. The main restriction for these systems is thermal conductivity weakness of common PCMs. As PCM is having low thermal conductivity, it increases the melting and solidification time, which is not suitable for specific application like electronic cooling. In order to increase the thermal conductivity nanoparticles are introduced. Adding the nanoparticles in base PCM increases the thermal conductivity. Increase in weight concentration increases the thermal conductivity. This paper numerically investigates the thermal energy storage panel with nanoparticle enhanced phase change material. Silver nanostructure have increased the thermal properties of the base PCM, eicosane. Different weight concentration (1, 2, 3.5, 5, 6.5, 8, 10%) of silver enhanced phase change material was considered. Both steady state and transient analysis was performed to compare the characteristics of nanoparticle enhanced phase material at different heat loads. Results showed that in steady state, the temperature near the front panel reduced and temperature on NePCM panel increased as the weight concentration increased. With the increase in thermal conductivity more heat was absorbed into the NePCM panel. In transient analysis, it was found that the effect of nanoparticle concentration on maximum temperature of the system was reduced as the melting point of the material reduced with increase in weight concentration. But for the heat load of maximum 20W, the model with NePCM did not attain the melting point temperature. Therefore it showed that the model with NePCM is capable of holding more heat load. In order to study the heat load capacity double the load is given, maximum of 40W was given as first half of the cycle and the other is given constant OW. Higher temperature was obtained comparing the other heat load. The panel maintained a constant temperature for a long duration according to the NePCM melting point. In both the analysis, the uniformity of temperature of the TESP was shown. Using Ag-NePCM it allows maintaining a constant peak temperature near the melting point. Therefore, by altering the weight concentration of the Ag-NePCM it is possible to create an optimum operating temperature required for the effective working of the electronics components.

Keywords: carbon-fiber-reinforced polymer, micro/nano-satellite, nanoparticle phase change material, thermal energy storage

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Authors: Oriahi Love Ndidi

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High concentration photovoltaic promises a more efficient, higher power output than traditional photovoltaic modules. One of the driving forces of this high system efficiency has been the continuous improvement of III-V multi-junction solar cell efficiencies. Multi-junction solar cells built from III-V semiconductors are being evaluated globally in concentrated photovoltaic systems designed to supplement electricity generation for utility companies. The high efficiency of this III-V multi-junction concentrator cells, with demonstrated efficiency over 40 percent since 2006, strongly reduces the cost of concentrated photovoltaic systems, and makes III-V multi-junction cells the technology of choice for most concentrator systems today.

Keywords: cost of multi-junction solar cell, efficiency, photovoltaic systems, reliability

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Authors: Muhammad Ramzan

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A mathematical model has been envisaged to discuss three-dimensional Viscoelastic fluid flow with an effect of Cattaneo-Christov heat flux in attendance of magnetohydrodynamic (MHD). Variable thermal conductivity with the impact of homogeneous-heterogeneous reactions and convective boundary condition is also taken into account. Homotopy analysis method is engaged to obtain series solutions. Graphical illustrations depicting behaviour of sundry parameters on skin friction coefficient and all involved distributions are also given. It is observed that velocity components are decreasing functions of Viscoelastic fluid parameter. Furthermore, strength of homogeneous and heterogeneous reactions have opposite effects on concentration distribution. A comparison with a published paper has also been established and an excellent agreement is obtained; hence reliable results are being presented.

Keywords: Cattaneo Christov heat flux, homogenous-heterogeneous reactions, magnetic field, variable thermal conductivity

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Authors: Innocent Pangapanga-Phiri, Eric Dada Mungatana

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This study estimates the effect of climate-induced rural-urban migrants (RUM) on maize productivity. It uses panel data gathered by the National Statistics Office and the World Bank to understand the effect of RUM on the technical efficiency of maize production in rural Malawi. The study runs the two-stage Tobit regression to isolate the real effect of rural-urban migration on the technical efficiency of maize production. The results show that RUM significantly reduces the technical efficiency of maize production. However, the interaction of RUM and climate-smart agriculture has a positive and significant influence on the technical efficiency of maize production, suggesting the need for re-investing migrants’ remittances in agricultural activities.

Keywords: climate-smart agriculture, farm productivity, rural-urban migration, panel stochastic frontier models, two-stage Tobit regression

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Authors: Xiaohua Zou, Yongxin Su

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The reasonable operation of heating, ventilation, and air conditioning (HVAC) is of great significance in improving the security, stability, and economy of power system operation. However, the uncertainty of the operating environment, thermal comfort varies by users and rapid decision-making pose challenges for HVAC demand response optimization. In this regard, this paper proposes a reinforcement learning-based method for HVAC demand response optimization considering few-shot personalized thermal comfort (PTC). First, an HVAC DR optimization framework based on few-shot PTC model and DRL is designed, in which the output of few-shot PTC model is regarded as the input of DRL. Then, a few-shot PTC model that distinguishes between awake and asleep states is established, which has excellent engineering usability. Next, based on soft actor criticism, an HVAC DR optimization algorithm considering the user’s PTC is designed to deal with uncertainty and make decisions rapidly. Experiment results show that the proposed method can efficiently obtain use’s PTC temperature, reduce energy cost while ensuring user’s PTC, and achieve rapid decision-making under uncertainty.

Keywords: HVAC, few-shot personalized thermal comfort, deep reinforcement learning, demand response

Procedia PDF Downloads 62

Authors: Amirhossein Eisapour, Mohammad Emamjome Kashan, Alan S. Fung

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This research addresses the pressing global challenges of clean energy and water supplies, emphasizing the need for sustainable solutions for the building sector. The research centers on integrating Reverse Osmosis (RO) systems with building energy systems, incorporating Solar Thermal Collectors (STC)/Photovoltaic Thermal (PVT), water-to-water heat pumps, and an Insulated Concrete Form (ICF) based building foundation wall thermal energy storage. The study explores an innovative configuration’s effectiveness in addressing water and heating demands through clean energy sources while addressing ICF-based thermal storage challenges, which could overheat in the cooling season. Analyzing four configurations—STC-ICF, STC-ICF-RO, PVT-ICF, and PVT-ICF-RO, the study conducts a sensitivity analysis on collector area (25% and 50% increase) and weather data (evaluating five Canadian cities, Winnipeg, Toronto, Edmonton, Halifax and Vancouver). Key outcomes highlight the benefits of integrated RO scenarios, showcasing reduced ICF wall temperature, diminished unwanted heat in the cooling season, reduced RO pump consumption and enhanced solar energy production. The STC-ICF-RO and PVT-ICF-RO systems achieved energy savings of 653 kWh and 131 kWh, respectively, in comparison to their non-integrated RO counterparts. Additionally, both systems successfully contributed to lowering the CO2 production level of the energy system. The calculated payback period of STC-ICF-RO (2 years) affirms the proposed systems’ economic viability. Compared to the base system, which does not benefit from the ICF and RO integration with the building energy system, the STC-ICF-RO and PVT-ICF-RO demonstrate a dramatic energy consumption reduction of 20% and 32%, respectively. The sensitivity analysis suggests potential system improvements under specific conditions, especially when implementing the introduced energy system in communities of buildings.

Keywords: insulated concrete form, thermal energy storage, reverse osmosis, building energy systems, solar thermal collector, photovoltaic thermal, heat pump

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Authors: Alexander Peikos, Carole Binsfeld

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The aim of this paper is to determine a thermally comfortable air temperature in an automated living room. This calculated temperature should serve as input for a user-specific and dynamic heating control in such a living space. In addition to the usual physical factors (air temperature, humidity, air velocity, and radiation temperature), individual clothing and activity should be taken into account. The calculation of such a temperature is based on different methods and indices which are usually used for the evaluation of the thermal comfort. The thermal insulation of the worn clothing is determined with a Radio Frequency Identification system. The activity performed is only taken into account indirectly through the generated heart rate. All these methods are ultimately very well suited for use in temperature regulation in an automated home, but still require further research and extensive evaluation.

Keywords: smart home, thermal comfort, predicted mean vote, radio frequency identification

Procedia PDF Downloads 146

Authors: Zeinab Sayed Abdel Rehim, M. A. Ziada, H. Salwa El-Deeb

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Numerical study of fluid flow, heat transfer and thermal energy storing or released in/from spongy-porous media to predict the thermal performance and characteristics of the porous media as packed bed system is presented in this work. This system is cylindrical channel filled with porous media (carbon foam). The system consists of working fluid (air) and spongy-porous medium; they act as the heat exchanger (heating or cooling modes) where thermal interaction occurs between the working fluid and the porous medium. The spongy-porous media are defined by the different type of porous medium employed in the storing or cooling modes. Two different porous media are considered in this study: Carbon foam, and Silicon rubber. The flow of the working fluid (air) is one dimensional in the axial direction from the top to downward and steady state conditions. The numerical results of transient temperature distribution for both working fluid and the spongy-porous medium phases and the amount of stored/realized heat inside/from the porous medium for each case with respect to the operating parameters and the spongy-porous media characteristics are illustrated.

Keywords: fluid flow, heat transfer, numerical analysis, spongy-porous media, thermal performance, transient conditions

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Authors: Zehra Aybike Kılıç, Alpin Köknel Yener

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Daylight is a powerful driver in terms of improving human health, enhancing productivity and creating sustainable solutions by minimizing energy demand. A proper daylighting system allows not only a pleasant and attractive visual and thermal environment, but also reduces lighting energy consumption and heating/cooling energy load with the optimization of aperture size, glazing type and solar control strategy, which are the major design parameters of daylighting system design. Particularly, in high-rise buildings where large openings that allow maximum daylight and view out are preferred, evaluation of daylight performance by considering the major parameters of the building envelope design becomes crucial in terms of ensuring occupants’ comfort and improving energy efficiency. Moreover, it is increasingly necessary to examine the daylighting design of high-rise residential buildings, considering the share of residential buildings in the construction sector, the duration of occupation and the changing space requirements. This study aims to identify a proper daylighting design solution considering window area, glazing type and solar control strategy for a high-residential building in terms of visual comfort and lighting energy efficiency. The dynamic simulations are carried out/conducted by DIVA for Rhino version 4.1.0.12. The results are evaluated with Daylight Autonomy (DA) to demonstrate daylight availability in the space and Daylight Glare Probability (DGP) to describe the visual comfort conditions related to glare. Furthermore, it is also analyzed that the lighting energy consumption occurred in each scenario to determine the optimum solution reducing lighting energy consumption by optimizing daylight performance. The results revealed that it is only possible that reduction in lighting energy consumption as well as providing visual comfort conditions in buildings with the proper daylighting design decision regarding glazing type, transparency ratio and solar control device.

Keywords: daylighting , glazing type, lighting energy efficiency, residential building, solar control strategy, visual comfort

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Authors: N. Türkmenoğlu Bayraktar, E. Kishalı

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Campus buildings are educational facilities where various amount of energy consumption for lighting, heating, cooling and ventilation occurs. Some of the new universities in Turkey, where this investigation takes place, still continue their educational activities in existing buildings primarily designed for different architectural programs and converted to campus buildings via changes of function, space organizations and structural interventions but most of the time without consideration of appropriate micro climatic conditions. Reducing energy consumption in these structures not only contributes to the national economy but also mitigates the negative effects on environment. Furthermore, optimum thermal comfort conditions should be provided during the refurbishment of existing campus structures and their building envelope. Considering this issue, the first step is to investigate the climatic performance of building elements regarding refurbishment process. In the context of the study Kocaeli University, Faculty of Design and Architecture building constructed in 1980s in Anıtpark campus located in the central part of Kocaeli, Turkey was investigated. Climatic factors influencing thermal conditions; the deteriorations on building envelope; temperature distribution; heat losses from façade elements observed by thermography were presented in order to improve strategies for retrofit process for the building envelope. Within the scope of the survey, refurbishment strategies towards providing optimum climatic comfort conditions, increasing energy efficiency of building envelope were proposed.

Keywords: building envelope, IRT, refurbishment, non-destructive test

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Authors: Anwar Beg, Sireetorn Kuharat, Rashid Mehmood, Rabil Tabassum, Meisam Babaie

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Nano-polymeric solar paints and sol-gels have emerged as a major new development in solar cell/collector coatings offering significant improvements in durability, anti-corrosion and thermal efficiency. They also exhibit substantial viscosity variation with temperature which can be exploited in solar collector designs. Modern manufacturing processes for such nano-rheological materials frequently employ stagnation flow dynamics under high temperature which invokes radiative heat transfer. Motivated by elaborating in further detail the nanoscale heat, mass and momentum characteristics of such sol gels, the present article presents a mathematical and computational study of the steady, two-dimensional, non-aligned thermo-fluid boundary layer transport of copper metal-doped water-based nano-polymeric sol gels under radiative heat flux. To simulate real nano-polymer boundary interface dynamics, thermal slip is analysed at the wall. A temperature-dependent viscosity is also considered. The Tiwari-Das nanofluid model is deployed which features a volume fraction for the nanoparticle concentration. This approach also features a Maxwell-Garnet model for the nanofluid thermal conductivity. The conservation equations for mass, normal and tangential momentum and energy (heat) are normalized via appropriate transformations to generate a multi-degree, ordinary differential, non-linear, coupled boundary value problem. Numerical solutions are obtained via the stable, efficient Runge-Kutta-Fehlberg scheme with shooting quadrature in MATLAB symbolic software. Validation of solutions is achieved with a Variational Iterative Method (VIM) utilizing Langrangian multipliers. The impact of key emerging dimensionless parameters i.e. obliqueness parameter, radiation-conduction Rosseland number (Rd), thermal slip parameter (α), viscosity parameter (m), nanoparticles volume fraction (ϕ) on non-dimensional normal and tangential velocity components, temperature, wall shear stress, local heat flux and streamline distributions is visualized graphically. Shear stress and temperature are boosted with increasing radiative effect whereas local heat flux is reduced. Increasing wall thermal slip parameter depletes temperatures. With greater volume fraction of copper nanoparticles temperature and thermal boundary layer thickness is elevated. Streamlines are found to be skewed markedly towards the left with positive obliqueness parameter.

Keywords: non-orthogonal stagnation-point heat transfer, solar nano-polymer coating, MATLAB numerical quadrature, Variational Iterative Method (VIM)

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Authors: Paulo H. R. G. Reis, Joana P. Maia, Davi Neiva Alves, Mariana R. C. Aquino, Igor B. Guimaraes, Anderson Horta, Thiago Santiago, Mariana Volpini

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Additive manufacturing is a manufacturing technique used in many fields as a tool for the production of complex parts accurately. This technique has a wide possibility of applications in bioengineering, mainly in the manufacture of orthopedic devices, thanks to the versatility of shapes and surface details. The present article aims to evaluate the mechanical viability of a wrist-hand orthosis made using additive manufacturing techniques with Nylon 12 polyamide and compare this device with the wrist-hand orthosis manufactured by the traditional process with thermoplastic Ezeform. The methodology used is based on the application of computational simulations of voltage and temperature, from finite element analysis, in order to evaluate the properties of displacement, mechanical stresses and thermal comfort in the two devices. The execution of this work was carried out through a case study with a 29-year-old male patient. The modeling software involved was Meshmixer from US manufacturer Autodesk and Fusion 360 from the same manufacturer. The results demonstrated that the orthosis developed by 3D printing, from Nylon 12, presents better thermal comfort and response to the mechanical stresses exerted on the orthosis.

Keywords: additive manufacturing, finite elements, hand orthosis, thermal comfort, neurorehabilitation

Procedia PDF Downloads 174

Authors: А. I. Dovgyalo, S. O. Nekrasova, D. V. Sarmin, A. A. Shimanov, D. A. Uglanov

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Usually liquefied natural gas (LNG) gasification is performed due to atmospheric heat. In order to produce a liquefied gas a sufficient amount of energy is to be consumed (about 1 kW∙h for 1 kg of LNG). This study offers a number of solutions, allowing using a cold energy of LNG. In this paper it is evaluated the application turbines installed behind the evaporator in LNG complex due to its work additional energy can be obtained and then converted into electricity. At the LNG consumption of G=1000kg/h the expansion work capacity of about 10 kW can be reached. Herewith-open Rankine cycle is realized, where a low capacity cryo-pump (about 500W) performs its normal function, providing the cycle pressure. Additionally discussed an application of Stirling engine within the LNG complex also gives a possibility to realize cold energy. Considering the fact, that efficiency coefficient of Stirling engine reaches 50 %, LNG consumption of G=1000 kg/h may result in getting a capacity of about 142 kW of such a thermal machine. The capacity of the pump, required to compensate pressure losses when LNG passes through the hydraulic channel, will make 500 W. Apart from the above-mentioned converters, it can be proposed to use thermoelectric generating packages (TGP), which are widely used now. At present, the modern thermoelectric generator line provides availability of electric capacity with coefficient of efficiency up to 15%. In the proposed complex, it is suggested to install the thermoelectric generator on the evaporator surface is such a way, that the cold end is contacted with the evaporator’s surface, and the hot one – with the atmosphere. At the LNG consumption of G=1000 kgг/h and specified coefficient of efficiency the capacity of the heat flow Qh will make about 32 kW. The derivable net electric power will be P=4,2 kW, and the number of packages will amount to about 104 pieces. The carried out calculations demonstrate the research perceptiveness in this field of propulsion plant development, as well as allow realizing the energy saving potential with the use of liquefied natural gas and other cryogenics technologies.

Keywords: cold energy, gasification, liquefied natural gas, electricity

Procedia PDF Downloads 263

Authors: Ghazi Faisal Najmuldeen, Ali Abdul Rahman–Al Ezzi, Tharmathas A/L Alagappan

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The aim of this investigation was to produce biofuel from castor oil through microwave assisted thermal cracking with zeolite ZSM-5 as catalyst. The obtained results showed that microwave assisted thermal cracking of castor oil with Zeolite ZSM-5 as catalyst generates products consisting of alcohol, methyl esters and fatty acids. The products obtained from this experimental procedure by the cracking of castor oil are components of biodiesel. Samples of cracked castor oil containing 1, 3 and 5wt % catalyst was analyzed, however, only the sample containing the 5wt % catalyst showed significant presence of condensate. FTIR and GCMS studies show that the condensate obtained is an unsaturated fatty acid, is 9, 12-octadecadienoic acid, suitable for biofuel use. 9, 12-octadecadienoic acid is an unsaturated fatty acid with a molecular weight of 280.445 g/mol. Characterization of the sample demonstrates that functional group for the products from the three samples display a similar peak in the FTIR graph analysis at 1700 cm-1 and 3600 cm-1. The result obtained from GCMS shows that there are 16 peaks obtained from the sample. The compound with the highest peak area is 9, 12-octadecadienoic acid with a retention time of 9.941 and 24.65 peak areas. All these compounds are organic material and can be characterized as biofuel and biodiesel.

Keywords: castor oil, biofuel, biodiesel, thermal cracking, microwave

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Authors: Alaaddin Cerit, Suheyla Kocaman, Ulku Soydal

Abstract:

During the past two decades, photoinitiated polymerization has been attracting a great interest in terms of scientific and industrial activity. The wide recognition of UV treatment in the polymer industry results not only from its many practical applications but also from its advantage for low-cost processes. Unlike most thermal curing systems, radiation-curable systems can polymerize at room temperature without additional heat, and the curing is completed in a very short time. The advantage of cationic UV technology is that post-cure can continue in the ‘dark’ after radiation. In this study, bio-based acrylated epoxidized soybean oil (AESO) was cured with UV radiation using radicalic photoinitiator Irgacure 184. Triarylsulphonium hexafluoroantimonate was used as cationic photoinitiator for curing of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate. The effect of curing time and the amount of initiators on the curing degree and thermal properties were investigated. The thermal properties of the coating were analyzed after crosslinking UV irradiation. The level of crosslinking in the coating was evaluated by FTIR analysis. Cationic UV-cured coatings demonstrated excellent adhesion and corrosion resistance properties. Therefore, our study holds a great potential with its simple and low-cost applications.

Keywords: acrylated epoxidized soybean oil, epoxy carboxylate, thermal properties, uv-curing

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Authors: Dilin Chen, Kang Luo, Jian Wu, Chun Yang, Hongliang Yi

Abstract:

Electrically driven flows (EDF) systems play an important role in fuel cells, electrochemistry, bioseparation technology, fluid pumping, and microswimmers. The core scientific problem is multifield coupling, the further development of which depends on the exploration of nonlinear instabilities, force competing mechanisms, and energy budgets. In our study, two categories of electrostatic force-dominated phenomena, induced charge electrosmosis (ICEO) and ion conduction pumping are investigated while considering polymer rheological characteristics and heat gradients. With finite volume methods, the thermal modulation strategy of ICEO under the thermal buoyancy force is numerically analyzed, and the electroelastic instability turn associated with polymer addition is extended. The results reveal that the thermal buoyancy forces are sufficient to create typical thermogravitational convection in competition with electroconvective modes. Electroelastic instability tends to be promoted by weak electrical forces, and polymers effectively alter the unstable transition routes. Our letter paves the way for improved mixing and heat transmission in microdevices, as well as insights into the non-Newtonian nature of electrohydrodynamic dynamics.

Keywords: non-Newtonian fluid, electroosmotic flow, electrohydrodynamic, viscoelastic liquids, heat transfer

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Authors: Siti Noor Baiti Binti Mustafa

Abstract:

Energy management studies regarding energy efficiency investments in Malaysia has yet to address the lack of empirical research that examines pro- sustainability behavior of managers in the industrial sector and how it influences energy efficiency investment decision-making. This study adopts the Theory of Planned Behavior (TPB) to examine the relationship between personal attitude, subjective norms, and perceived behavioral control (PBC), the intention of energy efficiency investments, and how perceptions of Non-Energy Benefits (NEB) influence these intentions among managers in the industrial sector in Malaysia. Managers from various sub-sectors in the industrial sector were selected from a sample of companies that are participants of the Government-led program named the Energy Audit Conditional Grant (EACG) that aimed to promote energy efficiency. Data collection was conducted through an online semi-structured, open-ended questionnaire and then later interviewed. The results of this explorative sequential qualitative study showed that perceived behavioral control was a significant predictor of energy efficiency investment intentions as compared to factors such as attitude and subjective norms. The level of awareness and perceptions towards NEB further played a significant factor in influencing energy efficiency investment decision-making as well. Various measures and policy recommendations are provided together with insights on factors that influence decision-makers intention to invest in energy efficiency, whilst new knowledge on NEB perceptions will be useful to enhance the attractiveness of energy-efficient investments.

Keywords: energy efficiency investments, non-energy benefits, theory of planned behavior, personal attitude, subjective norms, perceived behavioral control, Malaysia industrial sector

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Authors: Sireetorn Kuharat, Anwar Beg

Abstract:

Motivation- Solar energy constitutes the most promising renewable energy source on earth. Nanofluids are a very successful family of engineered fluids, which contain well-dispersed nanoparticles suspended in a stable base fluid. The presence of metallic nanoparticles (e.g. gold, silver, copper, aluminum etc) significantly improves the thermo-physical properties of the host fluid and generally results in a considerable boost in thermal conductivity, density, and viscosity of nanofluid compared with the original base (host) fluid. This modification in fundamental thermal properties has profound implications in influencing the convective heat transfer process in solar collectors. The potential for improving solar collector direct absorber efficiency is immense and to gain a deeper insight into the impact of different metallic nanoparticles on efficiency and temperature enhancement, in the present work, we describe recent computational fluid dynamics simulations of an annular solar collector system. The present work studies several different metallic nano-particles and compares their performance. Methodologies- A numerical study of convective heat transfer in an annular pipe solar collector system is conducted. The inner tube contains pure water and the annular region contains nanofluid. Three-dimensional steady-state incompressible laminar flow comprising water- (and other) based nanofluid containing a variety of metallic nanoparticles (copper oxide, aluminum oxide, and titanium oxide nanoparticles) is examined. The Tiwari-Das model is deployed for which thermal conductivity, specific heat capacity and viscosity of the nanofluid suspensions is evaluated as a function of solid nano-particle volume fraction. Radiative heat transfer is also incorporated using the ANSYS solar flux and Rosseland radiative models. The ANSYS FLUENT finite volume code (version 18.1) is employed to simulate the thermo-fluid characteristics via the SIMPLE algorithm. Mesh-independence tests are conducted. Validation of the simulations is also performed with a computational Harlow-Welch MAC (Marker and Cell) finite difference method and excellent correlation achieved. The influence of volume fraction on temperature, velocity, pressure contours is computed and visualized. Main findings- The best overall performance is achieved with copper oxide nanoparticles. Thermal enhancement is generally maximized when water is utilized as the base fluid, although in certain cases ethylene glycol also performs very efficiently. Increasing nanoparticle solid volume fraction elevates temperatures although the effects are less prominent in aluminum and titanium oxide nanofluids. Significant improvement in temperature distributions is achieved with copper oxide nanofluid and this is attributed to the superior thermal conductivity of copper compared to other metallic nano-particles studied. Important fluid dynamic characteristics are also visualized including circulation and temperature shoots near the upper region of the annulus. Radiative flux is observed to enhance temperatures significantly via energization of the nanofluid although again the best elevation in performance is attained consistently with copper oxide. Conclusions-The current study generalizes previous investigations by considering multiple metallic nano-particles and furthermore provides a good benchmark against which to calibrate experimental tests on a new solar collector configuration currently being designed at Salford University. Important insights into the thermal conductivity and viscosity with metallic nano-particles is also provided in detail. The analysis is also extendable to other metallic nano-particles including gold and zinc.

Keywords: heat transfer, annular nanofluid solar collector, ANSYS FLUENT, metallic nanoparticles

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Authors: Zafar Mahmood, Fahimullah Babar, Surriyia Naz, Hafiz Ur Rehman

Abstract:

Cadmium Sulphide (CdS) was deposited on a Tec 15 glass substrate with the help of CBD (chemical bath deposition process) and then cadmium telluride CdTe was deposited on CdS with the help of CSS (closed spaced sublimation technique) for the construction of a solar cell. The thicknesses of all the deposited materials were measured with the help of Elipsometry. The IV graphs were drawn in order to observe the current voltage output. The efficiency of the cell was graphed with the fill factor as well (graphs not given here).The efficiency came out to be approximately 16.5 % and the CIGS (copper- indium –gallium- selenide) maximum efficiency is 20 %.The efficiency of a solar cell can further be enhanced by adapting quality materials, good experimental devices and proper procedures. The grain size was analyzed with the help of scanning electron microscope using RBS (Rutherford backscattering spectroscopy).

Keywords: CBD, CdS, CdTe, CSS

Procedia PDF Downloads 352

Authors: Gokhan Sir, Muhammed Ergun, Onder Balioglu

Abstract:

Nowadays, laundry dryers containing heaters and heat pumps are used to provide fast and efficient drying. In this system, as the drying capacity changes, the sensible and latent heat transfer rate in the evaporator changes. Therefore, the drying time measured for the unit capacity increases as the drying capacity decreases. The objective of this study is to investigate the evaporator efficiency according to load amount and textile type in hybrid heat pump dryers. Air side flow rate and system temperatures (air side and refrigeration side) were monitored instantly, and the specific moisture extraction rate (SMER), evaporator efficiency, and heat transfer mechanism between the textile and hybrid heat pump system were examined. Evaporator efficiency of heat pump dryers for cotton and synthetic based textile types in load amounts of 2, 5, 8 and 10 kg were investigated experimentally. As a result, the maximum evaporator efficiency (%72) was obtained in drying cotton and synthetic based textiles with a capacity of 5 kg; the minimum evaporator efficiency (%40) was obtained in drying cotton and synthetic based textiles with a capacity of 2 kg. The experimental study also reveals that capacity-dependent flow rate changes are the major factor for evaporator efficiency.

Keywords: evaporator, heat pump, hybrid, laundry dryer, textile

Procedia PDF Downloads 119

Authors: Vipresh Mehta , Aman Abhishek, Jatin Batra, Gautam Iyer

Abstract:

Huge amount of solar radiation reaching the earth can be harnessed to provide electricity through Photo voltaic (PV) panels. The solar PV is an exciting technology but suffers from low efficiency. A study on low efficiency in multi MW solar power plants reveals that the electric yield of the PV modules is reduced due to reflection of the irradiation from the sun and when a module’s temperature is elevated, as there is decrease in the voltage and efficiency. We intend to alter the structure of the PV system, We also intend to improve the efficiency of the Solar Photo Voltaic Panels by active cooling to reduce the temperature losses considerably and decrease reflection losses to some extent. Reflectors/concentrators and anti-reflecting coatings are also used to intensify the amount of output produced from the system. Apart from this, transformer-less Grid-tied Inverter. And also, a T-LCL immitance circuit is used to reduce the harmonics and produce a constant output from the entire system.

Keywords: PV panels, efficiency improvement, active cooling, quantum dots, organic-inorganic hybrid 3D panel, ground water tunneling

Procedia PDF Downloads 755