Electricity Generation from Low and Medium Temperature Industrial Excess Heat in the Kraft Pulp and Paper Industry

The recovery and utilisation of industrial excess heat has been identified as an important contribution for energy efficiency by reducing primary energy demand. Previous works, based on top-down studies for a few sectors, or regional case studies estimated the overall availability of industrial excess heat. A more detailed analysis is required to allow the estimation of potentials for specific heat recovery technologies, particularly regarding excess heat temperature profiles. This work combines process integration methods and regression analysis to obtain cogeneration targets, detailed excess heat temperature profiles and estimations of electricity generation potentials from low and medium temperature excess heat. The work is based on the use of excess heat temperature (XHT) signatures for individual sites and regression analysis using publicly available data, obtaining estimations of the technical potential for electricity generation from low and medium temperature excess heat (60–140 °C) for the whole Swedish kraft pulp and paper industry. The results show a technical potential to increase the electricity production at kraft mills in Sweden by 10 to 13%, depending on the level of process integration considered, and a lower availability of excess heat than previously estimated in studies for the sector. The approach used could be adapted and applied in other sectors and regions, increasing the level of detail at which industrial excess heat estimations are obtained when compared to previous studies.

Numerical Solution of Energy Equation in Porous Channels under Effects of Radiation Field

In this paper, we built a mathematical model for convection and thermal radiation heat transfer of fluid flowing through a vertical channel with porous medium under effects of horizontal magnetic field (MF) at the channel. This model represents a 2-dimensional system of non-linear partial differential equations. Then, we solved this system numerically by finite difference methods using Alternating Direction Implicit (ADI) Scheme in two phases (steady state and unsteady state). Moreover, we found the distribution and behaviour of the heat temperature inside the channel and studied the effects of Brinkman number, Reynolds number, and Boltzmann number on the heat temperature behaviour. We solved the system by building a computer program using MATLAB.

Experimental Investigation of Innovative Thermal Mechanical Refrigeration System

The current electrical refrigeration and air condition systems are considered as one of the major sources for ozone depletion and global warming problems. Furthermore, they consume a large percentage of the worldwide gross production of electricity (around 17%). Therefore, developing new refrigeration systems that might be able to work using renewable sources (solar, geothermal, etc.) and waste heat sources is necessary to address these problems. In this paper, the experimental investigation of an innovative thermal-mechanical refrigeration (TMR) system is presented. The TMR system replaces the electric compressor of the conventional refrigeration systems with an innovative expander-compressor unit (two connected double-acting cylinders). The proposed ECU can be driven by ultra-low heat temperature sources, has simple configuration, and high flexibility for the operating conditions. A hybrid electric-compressor and ECU refrigeration setup was developed to investigate the performance of the ECU and compare it to that of an electric compressor. The experiment was conducted using R134a as a working fluid at different masses. The results show that a maximum COP of 0.57 is obtained at a refrigerant mass of 30g (in electric mode) and a maximum COP of 0.41 is obtained at a refrigerant mass of 60g (in ECU mode).

Performance of Thermal Insulation Covering Materials to Reduce Postharvest Losses in Okra

The efficiency of different thermal insulation covers in minimizing temperature fluctuations in cool chain management was investigated to reduce postharvest loss and maintain okra quality during storage and transportation. The four thermal insulation covering materials: (1) heat reflective sheet with thin nonwoven (HRS + TNNW), (2) heat reflective sheet with thick nonwoven (HRS + TKNW), (3) metalized Tyvek® (MTyvek) and (4) metalized foam sheet (MFS) were studied and compared with perforated linear low-density polyethylene (P-LLDPE) as the typical handing package for okra distribution alongside no covering as the control. The material properties, transpiration rate, vital heat, temperature profiles (air and pulp temperatures), relative humidity, mass loss and incidence of decay were determined throughout a simulated supply chain. Results exhibited that HRS + TNNW and HRS + TKNW covers had the lowest thermal heat energy (Qx) and moderate R-value. These two covers maintained low temperature fluctuation with the lowest rate of air and pulp temperature changes, reflecting in lowest mass loss and decay in okra. The HRS + TNNW cover yielded less decay (1%) in okra, compared to commercial covers; MTyvek (16%) and MFS (9%). Results showed that HRS + TNNW exhibited great potential as a thermal insulation cover to reduce postharvest loss in okra (5%) compared to typical handling (11–18%) and could be considered as alternative material to reduce the use of foam sheets in cool chain management distribution packaging of okra under ambient environment conditions.

Comsolic solution of an elliptic cylindrical compressible fluid flow

In this article, the primary focus is to investigate the heat transfer effects with viscous compressible laminar flow in the permeable elliptic cylinder. The Reynolds number is kept 100 for flow to be laminar. The physics of heat transfer is selected to be coupled with the laminar flow. The results for particular step-size time for Velocity distribution, pressure profile, temperature profile, isothermal temperature contours, and drag coefficient have been analyzed. Mesh has been generated through COMSOL, mesh entities have been elaborated statistically. The maximum and minimum velocity profile is observed at the elliptical cylinder’s walls and upper, lower boundary respectively. The maximum velocity observed is 2.22 m/s. Pressure profile around elliptic corners is found maximum, distinct patterns are observed even under the influence of applied heat. Temperature is observed maximum at walls but it gradually increases as moving from the upper boundary towards the lower boundary. The isothermal contour patterns are observed maximum near the walls, drag coefficient of gradual decrease is observed. COMSOL multi-physics is utilized for mathematical modeling of problems and the Backward-Differentiation-Formula has been exploited to handle problems numerically. The results will help greatly to understand the characterizations of viscous fluids and in industries like air furnaces and automobile cooling systems.

The Hazards Analysis of Nickel-Rich Lithium-Ion Battery Thermal Runaway under Different States of Charge

The lithium-ion battery industry has been developing rapidly, with energy density and capacity constantly improving. However, the ensuing safety accidents of lithium-ion power batteries have seriously threatened the personal safety of passengers. Therefore, more and more attention has been paid to the thermal safety research of lithium-ion batteries, such as thermal runaway (TR) mechanism analysis and prevention methods, etc. In this paper, the nickel-rich 18650 lithium-ion batteries with Li[Ni0.8Co0.1Mn0.1]O2 cathode in different states of charge (SOC) are taken to investigate the TR characteristics using an extended volume plus acceleration calorimeter (EV+-ARC). In order to evaluate the TR characteristics, some characteristic parameters such as battery voltage, surface temperature, temperature rise rate, etc. are selected from the experiment to analyze the influence of SOC on the critical state of TR. It can be seen from the experiment results that the maximum temperature of the battery surface decreases with the decrease of SOC, while the self-generated heat temperature and TR trigger temperature increases with the decrease of SOC.

Performance analysis on series and parallel circuit configurations of a four-cell thermoelectric generator module design

This study presents a technique in recovering energy from low-grade waste heat of a Proton Exchange Membrane Fuel Cell (PEMFC). The goal is to study the functionality and performance using a multiple cell thermoelectric generator (TEG) module. The test bench consists of a heating element, a test section, and a cooling section. The heating element supplies a hot stream temperature of 53°C and 58°C that represents the waste heat from an actual PEMFC stack. The module comprises four TEG cells with heat pipes coupled with a heat sink system. The main variables were the TEG cooling modes of natural convection (0 m/s) and forced convection (at 5 m/s and 10 m/s) and the series and parallel circuit configurations of the module. At 58°C waste heat temperature, forced convection cooling at 10 m/s gave the highest voltage and power output of 140 mV and 1960 µW. The outputs of the series circuit was 159% higher than the parallel circuit. This initial simple TEG module design has shown that it has a good prospect to compensate for the ultra-low waste heat temperature of a PEMFC. Future designs of the modules need to identify a more optimized approach to improve the outputs and contribute to the long-term sustainability of PEMFC systems.

Human teeth as a reliable age marker: A study on migrant labour population

Age is one among the factors which is supposed to be identified in establishing identity of an unknown or deceased person. It is found to be more reliable and accurate to determine the age of a person. The determination of age can be achieved from various physical markers present in body, this includes teeth, bones, and skull. There is certain age where the long bones tend to complete their growth, the growth of skull is well marked by the time of order of their suture closures. A well-developed cranial bone depicts that it is intersected with a suture. besides the bone and skull another reliable physical marker is the human teeth, teeth is considered to be the hardest tissue in humans which is not affected by the factors such as heat, temperature, moisture etc. it is an effective identifier in cases of mass disaster where it is practically impossible to determine the identity of the person through the bones available from the crime site. Teeth is a very important factor to determine the age in disputed cases. Since the age can be estimated even from skeletal remains, teeth are preferred for estimation in certain cases as it is considered to be one among the hardest tissues of the human body. Teeth has got a very unique feature as it cannot be destroyed by heat or any thermal factors or other environmental factors. This property of the teeth has to be effectively utilized for age estimation. The following study was conducted on migrant workers working on a peeling company, the purpose behind the study is to determine whether all the workers have 18 years of age and to ensure that no or none of them are working below the age of 18. There are certain cases reporting that some of these workers have found committing impersonating forgery claiming to be above 18 years of age. The study is specifically to find the age of workers by examining the teeth and also to find if any forgery is done or not. This study was also done to check whether labor laws has been violated or not in accordance with the Constitution of India, no child below the age fourteen years of age shall be employed to work in any factory or mine or engaged in any other hazardous employment, therefore employment of a child under the age of 14 years is punishable by law (child labor prohibition and regulation act of 2012). The need of the study arises from this very fact that the proof of age is not an authenticated document. With repeated reports of forgery regarding the proof of age, submitting ration card as proof of age. And in the wake of current scenarios to ensure that no child is exploited in any kind of ways. The study was done on migrant labor population working in a factory and the estimation is carried out using the Demirjian method along with Acharya’s India specific value and the probable age of the respondents are calculated.