Analysis of potential waste heat recovery from a stenter in a textile plant

The textile sector, an important economic driving force in Antioquia, Colombia, uses great quantities of thermal energy mainly produced by coal combustion, which holds enormous potential for recovery. One of the most common processes in a textile plant is heat setting, which uses a significant amount of thermal energy to adjust the properties of fabrics, such as shrinking, stiffness, pull strength, width, and stretching. In this study, we calculate the mass and energy balances of a stenter and propose a system to recover the energy available in its exhaust gases. The energy recovery potential in this heat setting process is 800.97 kW, which represents 87.2% of the total input energy. Additionally, we evaluate different heat exchangers to recover the available heat and present criteria to select them. Finally, thermosyphons, whose thermal efficiency was theoretically determined here, offer a promising alternative for heat recovery from actual stenters.

Effect of the combustion system on reduction of thermal specific energy consumption in an industrial high temperature process

This paper presents an experimental study carried out in an industrial furnace for frits production using different configurations of burners based on different combustion techniques such as enriched air combustion, flat-flame oxy-combustion and preheater air combustion. The residence time of combustion gases inside the furnace also was modified. Several combustion configurations were tested and its effects on productivity and thermal energy specific consumption and efficiency were determined. The results show that higher residence time of the combustion gases can decrease significantly the specific consumption of fuel, while the change of the burners and combustion techniques did not show significant effects on decreasing the energy consumption. However, it is highlighted that the oxy-combustion flat-flame burners produced the lowest specific consumption of fuel. Even though the experiments were conducted in a furnace for frit production, the corresponding results can also be applied to guide or improve other industrial high temperature processes.

Techno feasibility analysis of a concentrating solar thermal cooling systems at a university complex

Concentrating solar thermal (CST) energy applications are growing worldwide, especially in combined cooling, heat, and power processes. Building upon the analysis of a building’s thermal comfort, and software simulations for CST, the current study evaluates a solar conditioning system integrated with absorption systems. The cooling system is equipped with single-, double- and triple-effect configurations cycle, production parameters, and thermal storage. The required fraction of auxiliary energy for the system operation is estimated. The results indicate that the double effect system is the best configuration for the adopted location in Brazil. The system’s annual auxiliary energy demand is, approximately, 20%. Triple-effect systems require less energy at higher temperatures due to local direct radiation, which then leads to an intermittent operation and greater auxiliary energy demands. The methodology applied in this work could be adopted in different locations, with an emphasis on the possibility of testing smaller scale systems in small buildings.

The empirical correlation between shear wave velocity and penetration resistance for the eolian sand deposits in the city of Olmos-Peru

Shear wave velocities (Vs) and the number of blows of SPT (N) are parameters that are generally recorded in a geotechnical exploration campaign, in the literature there are several publications on the empirical correlations between N y Vs in different types of soil, the first studies being attributed to Japanese researchers in the 60s and 70s. North Peruvian pipeline was built on a recent quaternary eolian deposit, so a research area in Olmos near to the structure was used for tests. In the geotechnical research campaign were carried out in an arrangement multi-channel and standard penetration test in order to obtain Vs and N respectively. The correlations in this publication are for eolian sand deposits that can potentially be used in other regions with similar characteristics. The correlations presented are; N₆₀ - Vs considering and incorporating into the model the influence of the effective overload.

Modelling and simulation of a thermoelectric waste heat recovery system – TWRHS

The thermoelectric effect allows the direct conversion of thermal energy into electrical energy without the need for moving parts and its applications are endless, with only the availability of a temperature gradient. Combustion vehicles generate energy losses of up to 62% and it is estimated that efficiency with thermoelectric generators can be increased by up to 8%. In this work we propose a system of waste heat from exhaust gases from the thermoelectric effect. A computational model was developed using the finite element method. Based on the simulations, a set of curves of electrical variables can be made as a function of temperature. There is a good correlation between the model and datasheet data. Based on the modeled system, it was possible to evaluate a generation system with the generation of up to 120W with 5.8% efficiency, representing an increase of up to 3% in overall efficiency.

Evaluation of the shear wave velocity (VS) of an artificial carbonate sand obtained with the use of bender elements test

Carbonate sand is characterized by the presence of fragile grains, which may influence their mechanical response due to the imposed loading; especially cyclic loading. The shear wave velocity (VS) provides relevant information for the design of foundation inserted in this type of soil, which can be obtained from laboratory tests with the use of bender elements (BE). This paper aims to evaluate the VS value of a carbonate sand from triaxial tests with BE using three methods in the time domain. The influence of loading, unloading and cycling on VS is also evaluated. The results confirmed that the confining stress affects the dynamic parameters. At higher stress levels, the signals aremore susceptible to the near field effects and the dynamic parameters are less influenced by cycling.

Development of riverine hydrokinetic energy systems in Colombia and other world regions: a review of case studies

At a global level, hydrokinetic power has been considered as a renewable energy source, and it has become an attractive alternative for the rural electrification of non-interconnected areas with the presence of water resources. Aspects such as the low rural electrification rate, the increase in energy demand, the decrease in fossil reserves and the climate change, are some of the factors that have driven the use of this technology for the electricity production. The aim of this work is to give a review of the hydrokinetic energy potential of water resources, the requirements and impacts of the implementation of hydrokinetic technology in different countries, and the current development in the Colombian case. At present, it can be observed that the implementation of this technology in different regions of the world, especially in Colombia, has several challenges and barriers, including gaps in knowledge, information and data, such as well as limitations of water resources and infrastructure, finally, impacting on a low adoption of this technology. On the other hand, publications on studies of implementation and potential of hydrokinetic technology have been increasing over time, indicating that this topic has been gaining interest despite the challenges.

Investigation of the effect temperature on the performance of the photovoltaic solar design for the western Region of Paraná - Brazil

This paper show on impact of temperature decrease applied in Building Integrate Photovoltaics (BIPV) dimensioned on a photovoltaic solar tile with a superimposed photovoltaic arrangement model, in conditions of simulation of Standard Test Conditions for 1000 W/m2 irradiation, for maximum and minimum summer temperatures of Foz do Iguaçu city during 2017-2018. The simulation (Comsol Multiphysics®) uses different types for material tiles (concrete, polypropylene and PVC) and compares the system considering the influence of the materials in the civil-structural characteristics of the roof. The results showed that the efficiency behavior with temperature variations, produce a decrease of linear efficiency. While the, tile designs proposal has a 16% efficiency value in the datasheet in the same conditions. The results shows a decrease of efficiency and power with the increase temperature in the same conditions of the study, obtaining the respectively value of 0.05%/°C and 0.24%/°C.

GHG emissions offset of a combined-cycle natural gas-fired thermopower plant in Northeastern Brazil

Anthropogenic greenhouse gas (GHG) emissions have caused unprecedented climate change. Both mitigation and adaptation actions have thus become crucial. The combustion of fossil fuels is the leading cause of GHG emissions. Within this context, this work explores several options to offset GHG emissions from a combined-cycle natural gas-fired thermopower plant by 2050. Termopernambuco, in Northeastern Brazil, provides a case study that can be used as a reference for other projects. Therefore, after making an inventory and designing a scenario up to 2050 of its GHG emissions, mitigation actions and offset options are assessed, including a photovoltaic system, fuel mix options, a CO2 capture and storage (CCS) facility, and livestock-forest integration systems. Such measures are individually evaluated and bundled in five scenarios. Overall results indicate a wide range of offset costs, with livestock-forest integration systems at the lowest end with 37 USD/tCO2e up to a level of 180 USD/tCO2e for CCS.

Selection of earthquake ground motion accelerograms for the continental margin of Southeastern Brazil

Brazil is in an intraplate area of low to moderate seismicity, this means that few or no records of strong ground motions are available. Part of the site response analysis and seismic design of structures require the use of acceleration time-histories compatible with a specified target response spectrum. This study aims to utilize methodologies based on the use of existing earthquake records from a well-known database and synthetic accelerograms to obtain ground motions representative of the Brazilian Southeast Region, particularly in the offshore Campos Basin. Information from a probabilistic seismic hazard assessment performed in the interest area was employed as input to the methodologies applied in terms of target response spectrum and the dominant earthquake scenarios. Besides, the acceleration time-histories of two relatively recent earthquakes that occurred in the Brazilian Southeast were used to apply one of the approaches to obtain a synthetic spectrum compatible accelerogram.