Small Heater Research Articles

Heating decoys to mimic thermal signatures of live animals for drones

Thermal sensors mounted on drones (unoccupied aircraft systems) are popular and effective tools for monitoring cryptic animal species, although few studies have quantified sampling error of animal counts from thermal images. Using decoys is one effective strategy to quantify bias and count accuracy; however, plastic decoys do not mimic thermal signatures of representative species. Our objective was to produce heat signatures in animal decoys to realistically match thermal images of live animals obtained from a drone-based sensor. We tested commercially available methods to heat plastic decoys of three different size classes, including chemical foot warmers, manually heated water, electric socks, pad, or blanket, and mini and small electric space heaters. We used criteria in two categories, 1) external temperature differences from ambient temperatures (ambient difference) and 2) color bins from a palette in thermal images obtained from a drone near the ground and in the air, to determine if heated decoys adequately matched respective live animals in four body regions. Three methods achieved similar thermal signatures to live animals for three to four body regions in external temperatures and predominantly matched the corresponding yellow color bins in thermal drone images from the ground and in the air. Pigeon decoys were best and most consistently heated with three-foot warmers. Goose and deer decoys were best heated by mini and small space heaters, respectively, in their body cavities, with a heated sock in the head of the goose decoy. The materials and equipment for our best heating methods were relatively inexpensive, commercially available items that provide sustained heat and could be adapted to various shapes and sizes for a wide range of avian and mammalian species. Our heating methods could be used in future studies to quantify bias and validate methodologies for drone surveys of animals with thermal sensors.•We determined optimal heating methods for plastic animal decoys with inexpensive and commercially available equipment to mimic thermal signatures of live animals.•Methods could be used to quantify bias and improve thermal surveys of animals with drones in future studies.

Numerical investigation of an indirect solar dryer equipped with two solar air collectors using computational fluid dynamics

Generally, in most conventional solar dryers, there is one solar air heater, which means that the air enters the drying chamber from one side. The problem with a single inlet solar dryer, especially in natural convection, is that the air is not well distributed along the trays, resulting in the non-uniform moisture content of the final product. So, instead of using a large solar air heater, we divided it into two small solar air heaters facing the sun, each of which is connected to the drying chamber by pipes, leading to two inlets facing each other and supplying hot air from both sides.The CFD method was applied to study the airflow distribution in the proposed case. To be more realistic, we used a UDF (user-defined function) subroutine written in C++ to integrate the unsteady evolution of the climatic data for one day in the Oujda region (Eastern Morocco). A comparison between a solar dryer with one and two solar air heaters is presented. The effect of outlet position on air distribution is used as a criterion parameter for the study. All tests were performed using 2D modeling. The results showed that the optimum position of the outlet was in the right (North direction) and center corner for one and two solar air heaters, respectively. By comparing these two cases in terms of mass flow rate, temperature along the trays and inside the drying chamber it was found that the two solar air heaters dryer was more efficient, such as the drying efficiency reaches 97.36%.

Phenol red as electrochemical indicator for highly sensitive quantification of SARS-CoV-2 by loop-mediated isothermal amplification detection

The current COVID-19 pandemic has made patent the need for rapid and cost-effective diagnostic tests, crucial for future infectious outbreaks. Loop-mediated isothermal amplification (LAMP) is a promising and decentralized alternative to qPCR. In this work we have developed a sensitive, fast, and simple innovative methodology for quantification of SARS-CoV-2 RNA copies, combining reverse-transcription LAMP with electrochemical detection. This is based on the oxidation of phenol red (PR), a visual and electroactive LAMP indicator, which oxidation peak potential (Ep) changes with the progress of the LAMP reaction. Using that Ep shift as analytical signal, a calibration curve was obtained for fragment N1 copies of SARS-CoV2 (which provided better results than N or S fragments), with a potential shift of 16.2 mV per order of magnitude, and a practical limit of detection of 21 copies·μL−1. Moreover, the precision of Ep is excellent (RSD < 2%): 557 ± 5 mV for negative and 602 ± 7 mV for positive (2148 N fragment RNA copies·µL-1·-1) LAMP controls. This methodology has been applied to the analysis of nasopharyngeal swab samples, resulting in total concordance with clinical RT-qPCR results. Advances towards fully decentralization have been achieved by designing and fabricating a small portable heater for isothermal procedures, obtaining comparable results to those from a commercial benchtop thermal cycler.

Thermodynamic performance assessment and application feasibility analysis of small heat pump water heater using CO2/R41 azeotropy mixture as refrigerant for sustainable development

In order to improve the application possibility of CO2/R41 azeotropy mixture in the refrigeration industry, the optimum mass ratio of composition is defined and determined according to the thermodynamic properties and safety. On the basis of the first and second laws of thermodynamics, a model is proposed to evaluate the performance of CO2/R41 single-stage transcritical cycle (CO2/R41 cycle) in which a throttling valve is integrated and CO2/R41 azeotropy refrigerant is adopted. The performance of CO2/R41 cycle at the optimum mass ratio of CO2/R41 azeotropy mixture is then compared with that of a CO2 two-stage transcritical cycle with throttling valve (CO2 two-stage cycle) and that of a CO2 single-stage transcritical cycle with expander (CO2 expander cycle). The results show that the optimum mass ratio of CO2/R41 azeotropy mixture is 0.583/0.417. Compared with CO2 two-stage cycle and CO2 expander cycle, CO2/R41 cycle has the advantages of a simpler structure, lower optimum high pressure, appropriate discharge temperature of the compressor, and higher COP. Therefore, the CO2/R41 azeotropy mixture with the mass ratio of 0.583/0.417 is eco-friendly and can be considered as a good alternative refrigerant for application in the refrigeration industry. The simple CO2/R41 cycle shows great feasibility to replace the complex CO2 two-stage cycle and CO2 expander cycle.

Secondary air induced flow structures and mixing in a fixed bed combustor

Air staging features widely in biomass combustion from small space heaters to industrial-scale moving grate systems. Whilst studies have been conducted into the impact of air staging on emissions and combustion performance, there is little or no insight into the exact flow dynamic and physical mechanisms that are induced by secondary air under such conditions. This paper uses experimental data to validate numerical predictions before investigating the flow field structures and mixing characteristics in a fixed bed air staged combustor. The study utilizes Constant Temperature Anemometry (CTA) experiments to establish boundary conditions for a lab-scale fixed bed combustor. Results from numerical simulations obtained using [Formula: see text] l- 𝜔 model were in good agreement with experimental data. Conditions tested cover five different secondary to total air ratios (Qs/Qt) and two different locations of secondary air injection. Results show that at Qs/Qt = 0.50, 0.25 and 0.18 one strong recirculation zone is induced upstream of the secondary air injection and one downstream. Varying the point of injection of secondary air from h/D = 0.64 to h/D = 0.40 also had an effect on the size of the upstream recirculation zone. Qs/Qt = 0.50 had the highest values of mixing index among all spatially located planes at the upstream of secondary air injection. The overall findings shed light on the possible flow interactions between secondary air and the top layers of fuel bed. They also highlight the significance of secondary air on inducing both upstream and downstream flow structures.

Study on practical method of detection for characteristic change of controlled object by using FRIT and its applications to prototyped small heater

Study on practical method of detection for characteristic change of controlled object by using FRIT and its applications to prototyped small heater

RT-LAMP-Based Molecular Diagnostic Set-Up for Rapid Hepatitis C Virus Testing.

Hepatitis C virus (HCV) infections occur in approximately 3% of the world population. The development of an enhanced and extensive-scale screening is required to accomplish the World Health Organization’s (WHO) goal of eliminating HCV as a public health problem by 2030. However, standard testing methods are time-consuming, expensive, and challenging to deploy in remote and underdeveloped areas. Therefore, a cost-effective, rapid, and accurate point-of-care (POC) diagnostic test is needed to properly manage the disease and reduce the economic burden caused by high case numbers. Herein, we present a fully automated reverse-transcription loop-mediated isothermal amplification (RT-LAMP)-based molecular diagnostic set-up for rapid HCV detection. The set-up consists of an automated disposable microfluidic chip, a small surface heater, and a reusable magnetic actuation platform. The microfluidic chip contains multiple chambers in which the plasma sample is processed. The system utilizes SYBR green dye to detect the amplification product with the naked eye. The efficiency of the microfluidic chip was tested with human plasma samples spiked with HCV virions, and the limit of detection observed was 500 virions/mL within 45 min. The entire virus detection process was executed inside a uniquely designed, inexpensive, disposable, and self-driven microfluidic chip with high sensitivity and specificity.

Design a novel air to water pressure amplifier powered by PV system for reverse osmosis desalination

This work aims to design a novel standalone small-size air-to-water pressure amplifier (ATWPA) for RO desalination system with low energy consumption. A small DC PV system, pneumatic system, and solar water heater were designed and used to operate the ATWPA at different air pressure (1–5 bar) and heating water (30–45 °C), hence avoiding using a high-pressure and high-energy water pump. The ATWPA has a smart electronic circuit with a feedback system and controls the IR to synchronize the piston movement with pressure and water discharge. The feed air pressure was maximized from 5 bar to 27.9 bar, i.e. the pressure has amplified by 458% where it creates enough pressure to overcome the membrane resistance. The power consumption of ATWPA varied from 0.0 to 3.5 W in compression and suction strokes, respectively and maximum energy consumption was 105 Wh. Increasing feed water temperature and operating air pressure led to increasing freshwater productivity. The preheating of saline water to 45 °C and increasing pressure to 5 bar increased freshwater productivity to 58.8 L/h and decreased energy consumption.

Water jet impingement onto a hot steel plate

The research studies the interaction between subcooled small diameter water jet and thick steel heater at different surface temperatures, liquid velocities and jet angles. Although the heater surface temperature exceeded the Leidenfrost temperature and reached 340oC, the liquid, according to visual observations, wetted the surface. Geometrical characteristics of the heater surface wetted area and jet deflection angles were measured. It was hypothesised that jet deflection from the surface, accompanied by finely dispersed drops generation, occurs when thermal boundary layer, which develops in the liquid near the heater surface, reaches the liquid's outer surface. The preliminary measurements seem to confirm the hypothesis Keywords: Free-surface jet, quenching, jet impingement boiling, liquid film, Leidenfrost temperature.

A comprehensive review on integrated collector-storage solar water heaters

Conversion of solar energy to heat energy is a cost effective, sustainable and an efficient technology to heat water. Solar integrated collector-storage type of water heaters (ICSSWH) is a water heating device which alchemizes solar radiation directly into heat so that it is used for water heating. These systems are compact, simple in design and free from copper tubes bounded structures which unnecessarily causes heat losses and leakage issues. Their collection efficiency is usually higher than commonly used flat plate collectors (FPC). Despite of many advantages, the main disadvantage of compact integrated collection-storage type of water heaters (ICSSWH) is high heat losses during night hours which decreases the water affects the thus decreases the overall efficiency of the system. However, there are some strategies to minimize this heat loss from the system at the time when sunshine is not available; some of the methods are discussed in this paper. Moreover, in this article, the authors discuss the latest development in the new and improved compact water heater designs. In present paper authors critically reviewed various designs of ICSSWH. Use of insulated cover during night, introducing baffle plate structure, using PCM materials and using reverse thermosyphon valve are some of the strategies to minimize the heat losses from the system these methods are discussed in the present paper. Connecting tanks in series is also an effective method to overcome this problem of heat loss during night. In this paper the effect of connecting tanks in series on water temperature has been discussed. This paper presents an overall summary on compact ICSSWH systems which can be useful for further research to design and develop a new small size solar water heater.

Вскипание жидкой пленки при столкновении водяной струи с нагретой стальной поверхностью

The research studies the interaction between subcooled small diameter water jet and thick steel heater at different surface temperatures, liquid velocities and jet angles. Although the heater surface temperature exceeded the Leidenfrost temperature and reached 340℃, the liquid, according to visual observations, wetted the surface. Geometrical characteristics of the heater surface wetted area and jet deflection angles were measured. It was hypothesised that jet deflection from the surface, accompanied by finely dispersed drops generation, occurs when thermal boundary layer, which develops in the liquid near the heater surface, reaches the liquid's outer surface. The preliminary measurements seem to confirm the hypothesis.

A channel layout of a micro pulsating heat pipe for an excessively localized heating condition

A channel layout of a flat-plate micro pulsating heat pipe (MPHP) for an excessively localized heating condition is proposed. The excessively localized heating condition is implemented using a small heater, which covers only about 2% of the whole area, in the middle of the bottom part. To simplify the heat transfer characteristics in MPHPs, the channel regions are modeled as a region with the high effective thermal conductivity, and the topology optimization method is employed to determine a distribution of the channel regions of the MPHP. The constraints on the maximum length scale and the minimum solid volume fraction in local regions are imposed to take into account the operational characteristics of MPHPs. In the proposed channel layout, which is inspired by the topology optimization result, the channels are laid out in such a way that some channels are merged to reduce the number of channels. Due to a decrease in the number of channels, all channels are able to overlap the localized heating section without any thermally-isolated channel. To verify the effectiveness of the proposed method, the MPHPs with the channel layout designed by topology optimization and two kinds of channel layouts for the references are fabricated, and their flow characteristics and thermal performances are experimentally compared. In case of the MPHP with the uniform channel layout, only 4 channels out of 18 channels overlap the heating section, and the stagnant liquid slugs in the thermally-isolated channels are observed. On the other hand, in the MPHP with the channel layout designed by topology optimization, all channels overlap the heating section, and the active oscillating motion of the liquid slugs occurs in all channels. This allows the MPHP with the channel layout designed by topology optimization to have about two times higher thermal performance than the MPHP with the uniform channel layout. In this study, the channel layout of the MPHP for the excessively localized heating condition is firstly suggested, and the experimental results show that the proposed channel layout can effectively overcome the limitation associated with the localized heating condition.

Advanced Structurally Embedded Thermal Spreader Oscillating Heat Pipe Micro-Gravity Flight Experiment

On 7 September 2017, the U.S. Air Force Research Laboratory launched the second Advanced Structurally Embedded Thermal Spreader (ASETS-II) flight experiment on the fifth flight [Orbital Test Vehicle 5 (OTV-5)] of the Air Force’s X-37B spaceplane. OTV-5 landed on 27 October 2019 after 780 days on orbit. The ASETS-II flight experiment accomplished its mission to demonstrate functionality, characterize behavior, and explore the predicted limits of operation of oscillating heat pipes (OHPs) in a long-term microgravity environment. The three science objectives were to measure initial on-orbit thermal performance, long-duration thermal performance, and any lifetime degradation. The three OHPs on ASETS-II have varying configuration (center heating with large and small heaters and with single- and double-ended cooling) and heat pipe fluids (butane and R-134a) to isolate performance parameters of interest. Data collected during on-orbit operation are presented and favorably compared to predicted OHP limits of operation. Each OHP performed as expected with no notable differences between horizontal and microgravity flight data. All three OHPs started easily, had similar performance on ground and on orbit, showed no hysteresis effects or degradation on orbit, and performed well in several six-week-duration continuous operation tests both on the ground and in orbit.

Modern technologies for preheating scrap before charging it into electric arc steelmaking furnace

There are a number of technical solutions to utilize the waste gases of electric arc furnaces (EAF) for scrap preheating thus returning back the heat into the technological process. The waste gases can be utilized also for steam or hot water production. The preliminary scrap heating before charging it into EAF is more perspective. Technical features of various types scrap heaters considered, including conveyer and shaft scrap heating technologies with continuous (Contiarc, Consteel, Comelt, BBC-Brusa) and periodic charging (Fuchs Systemtechnik, COSS, backet). It was shown that application of scrap heaters for EAF ensures saving of electric energy, increase of metal yield, decrease of dust and gases level in the shop, decrease of negative impact on environment. The disadvantages include frequent and costly repairs of the facilities, impossibility to control some factors having effect on the process of scrap heating. It was shown that when designing new EAFs with a charge exceeding 100 t, horizontal facilities are more preferrable, while for EAFs of small volumes shaft heaters suit better. At EAF modernizing it is recommended to use shaft heaters and back­et-thermos, since it is easier to construct a vertical furnace than a horizontal one with minimal length of 100 m. It was noted that hor­izontal heaters operate better in terms of technology, since ensure continuous charging by scrap, but at that occupy a considerable space in the shop. When comparing vertical heaters and backet by all the characteristics including heat-engineering and designingones, vertical shaft heaters prevail.

4E (Energy, Exergy, Economic, and Environment) examination of a small LFR solar water heater: An experimental and numerical study

An experimental and numerical study on the solar water heater is carried out in Blida area, Algeria during winter in this work. Numerical results are confirmed by experimental results, where the numerical results are presented in two forms: Numerical solution based on estimated equations of climatic data and numerical solution based on actual values of weather data. Finite difference method was used to analyze and simplify energy balance equations. Results obtained showed a significant convergence between experimental and numerical results, where optical efficiency has passed 42.65 %, while the highest value for thermal efficiency was 29.212 % on February 22, 2015, while its average exergy efficiency for February 19, 2015 is 1.81 %. Experimentally, the maximum value of hot water temperature reached 352 K on February 19, 2015. As for the volume of water heated by the studied collector, it is 0.4 m3/day. The system performance is 19.75%, the equivalent of an electrical capacity of 545.68 kWh. Economically, the LFR reflector cost is 378.87 $, where this cost can be recovered after sixteen years of the first use, as the cost of heat generation is 0.043 $/kWh. Environmentally, the CO2 mitigation is 247.14 kg. Additionally, this reflector will provide the equivalent of 127.47 m3 of Liquefied natural gas.

Sustainable Economic Solution to Prevent the Wasted Cold Water in the Start of Shower Time Using Low Cost In-Line Electrical Heater with MISO Fuzzy Logic Controller

This paper discusses domestic problem of waiting hot water for the shower use till it reaches satisfactory temperature, which result a lot of wastage in fresh water. The outcome from research survey shows that there is no satisfactory solution till now as all solutions were either expensive or with no effective results. Local small inline electric heater equipped with fuzzy logic controller is proposed in this paper to be installed just before the showerhead to measure the water temperature and flow before the showerhead, as control input-variables, and decide the operating voltage of the heater, as control output-variable. Matlab Simulink is used to model the proposed system. Different test cases are simulated to prove the performance and the safe operation of the system. Techno-economic study is carried out to determine the “Direct Benefits” and “Indirect Benefits” that can be achieved if such system is implemented in wide range. Azerbaijan data is taken as an example to calculate the economic benefits. The results show important benefits not only for economy, that can increase fresh water sales opportunity to 545,088,171.52 $, but also for climate and the reduction of greenhouse gas emission. Different economic indices are provided to be an easy reference for decision makers and project managers.

Rancang Bangun Mesin Pemanas Akrilik Tipe Turbular Skala Industri Kecil

Acrylic is a material that is often used as a substitute for glass because it has the advantage that it is not easily broken and is lighter than glass. One of the processes of making objects made from acrylic is heating. The heating process that has been carried out by small industries is usually acrylic material heated manually by spraying fire from a gas-tube or using a small heater so that the size of acrylic that can be heated is limited, both in terms of length and thickness. The purpose of this research is to design and manufacture an acrylic heating machine that can be used up to a dimension of 600 mm wide and unlimited in length, and can heat up to a thickness of 10 mm with a continuous heating process and is relatively short. The design and manufacture includes the design of the heating system, the selection of the heater to be used, the design and manufacture of the acrylic table, the drive system and the frame. The test parameters include the maximum heating temperature, the acrylic bending temperature and the heating time. The result of the research is an acrylic heating machine that uses three straight turbular heaters with a 300 Watt heater each, capable of heating acrylic with a thickness of up to 10 mm as the initial process for the bending stage, at a heating dimension of 60 cm wide and unlimited in length. The suitable heating temperature for the bending process is 150 o C. The average heating time for the thickness 3mm is 91.5 seconds (1.5 minutes), 5mm (2.9 minutes) is 174.2 seconds and 10 mm is 451.3 seconds (7.5 minutes).

Evaluation Results of ERIT with a Small Heater with a Two-degrees-of-freedom Control System

Evaluation Results of ERIT with a Small Heater with a Two-degrees-of-freedom Control System

Stereoscopic detection of hot spots in superfluid 4He (He II) for accelerator-cavity diagnosis

Superconducting radio-frequency (SRF) cavities cooled by superfluid 4He (He II) are building blocks of many modern particle accelerators due to their high quality factor. However, Joule heating from sub-millimeter surface defects on cavities can lead to cavity quenching, which limits the maximum acceleration gradient of the accelerators. Developing a non-contacting detection technology to accurately locate these surface hot spots is the key to improve the performance of SRF cavities and hence the accelerators. In a recent proof-of-concept experiment (Phys. Rev. Applied, 11, 044003 (2019)), we demonstrated that a molecular tagging velocimetry (MTV) technique based on the tracking of a He2* molecular tracer line created nearby a surface hot spot in He II can be utilized to locate the hot spot. In order to make this technique practically useful, here we describe our further development of a stereoscopic MTV setup for tracking the tracer line’s motion in three-dimensional (3D) space. We simulate a quench spot by applying a transient voltage pulse to a small heater mounted on a substrate plate. Images of the drifted tracer line, taken with two cameras from orthogonal directions, are used to reconstruct the line profile in 3D space. A new algorithm for analyzing the 3D line profile is developed, which incorporates the finite size effect of the heater. We show that the center location of the heater can be reproduced on the substrate surface with an uncertainty of only a few hundred microns, thereby proving the practicability of this method.

Self‐Oscillation of Locally Heated Water Vapor Microbubbles in Degassed Water

AbstractThe self‐oscillation of water vapor microbubbles in degassed water is experimentally investigated by using the photothermal conversion effect of an FeSi2 thin film. A laser spot on the FeSi2 thin film is used as a heat resistant and localized heat source with flexible size and power. The local heating of the degassed water leads to the generation of a water vapor microbubble, which shows self‐oscillation at 0.1–0.7 MHz under continuous heating. The bubble oscillation frequency shows the maximum value when the absorbed power density reaches 1 mW µm−2 ( = 1 × 109 W m−2), regardless of the laser spot size. This value is close to the critical heat flux for highly subcooled boiling of water. The anomalous dependence of the self‐oscillation frequency on the input power density is explained by the transition from nucleate boiling to local film boiling. Additionally, a numerical analysis suggests that the bubble oscillation exceeding 1 mW µm−2 is attributed to the dried region on the laser spot and the periodic contact of the liquid water to the small heater. These results are useful for understanding and enhancing the flow generated around the water vapor bubble, and the design of microscale cooling devices.