Heater Temperature Research Articles

Water vapor desorption from silica gel in a combined drying and double-condenser compression refrigeration system

The drying method requires an effort to store food for a longer time. Some drying processes experience technical and economic weaknesses, mainly related to low efficiency, high energy costs, and decreased product quality. Various drying models have been studied to determine the suitability of heat and mass transfer analysis at drying rates in an air dehumidification scheme using different materials, one of which is silica gel. In this case, the researchers examined the effects of humidity, temperature, and airflow rate on the constant drying rate and activation energy of water desorption in silica gel using a packed bed dryer that was modified with a refrigeration system. This modified system aims to reduce specific energy consumption (SEC). The results demonstrate that the constant rate of water desorption in silica gel and the increase in air humidity cause a decrease in the constant value of the water desorption rate in silica gel. However, increases in the temperature and airflow cause an increase in the value of the constant drying rate for water desorption in silica gel, as they cause capillary evaporation. Meanwhile, the activation energy of water desorption in silica gel increases with decreasing air flow rate and increasing inlet air humidity. The attractive force acting on the water molecules from the surface force field on the surrounding walls becomes stronger if the air flow rate decreases or the air humidity increases. From the results and analysis, it is shown that the activation energy of water desorption in silica gel with significant air humidity and low flow rate, of 0.013 kg/kg d.a. (450 lpm), is the highest at 35.16 kJ/mol, whereas in silica gel with air humidity of 0.007 kg/kg d.a. (750 lpm), it is the lowest at 22.92 kJ/mol. Meanwhile, the dryer air flow rate, higher heater temperature, and lower air humidity improve the performance of the bed dryer against its evaporation rate and decrease the Specific Energy Consumption (SEC) value. SEC is also greatly influenced by the use condenser 1, which provides heater power savings of up to 79.1%. Thus, the system is expected to be applied to commercial drying systems that can work at low drying temperatures to maintain drying products and obtain low energy consumption.

Heat pulse testing at monitoring wells to estimate subsurface fluid velocities in geological CO2 storage

Monitoring the injected CO2 during geological CO2 storage (GCS) is essential to assure containment and identify CO2 leakage. In this work, a new approach is introduced to estimate the evolution of the downhole fluid velocity at a monitoring well and identify CO2 arrival time using in-well heat pulse/tracer test. The proposed technique involves using a downhole heater to generate a series of heat pulses and measuring their corresponding temperature response. The surface temperature of the downhole heater is controlled by the supplied electrical power and the heat loss by convection to the surroundings. Convective heat transfer is well described using Newton's law of cooling in which the temperature difference between the heater and the surrounding fluids drives the heat transfer, for which the convection heat transfer coefficient (h) controls the magnitude of heat loss. Among various factors that control h, it depends on the type of the flowing fluid and its velocity. Through analyzing the measured temperature at different heat pulses, the changes in h - due to mobilization of the in-situ brine or CO2 arrival - can be estimated. Consequently, the velocity of the flowing fluid across the heater can be obtained. Since heat transfer by convection is sensitive to the type of the surrounding fluid, intrusion of CO2 can be detected from the relatively higher surface temperature obtained at CO2 arrival. Churchill and Bernstein (1977)'s correlation is adopted to estimate the change of fluid velocity in terms of the change in h. To demonstrate the validity of the proposed technique, the results are applied and validated against those of COMSOL Multiphysics simulation tool for single-phase brine (before CO2 arrival) and single-phase CO2 (after CO2 arrival). The observed temperature heating is sensitive to the flowing fluid velocity and fluid type. The temperature signal observed at CO2 arrival is large and easily detectable using temperature monitoring tool which provides reliable indication for tracking CO2 arrival at monitoring wells compared with passive temperature monitoring. The results obtained using the proposed technique agree very well with the numerical results obtained from the simulation tool with a maximum estimation error of 7 percent.

Multidimensional wearable self-powered personal thermal management with scalable solar heating and a triboelectric nanogenerator

Global climate change is increasing the frequency of cold events, which can threaten health and enhance the demand for energy, inhibiting the society to prosper in a sustainable way. Having sun as the heat and body radiation as warmth preservation source, the need to save energy is mitigated through personal thermal management (PTM). Herein, we report a self-powered woven Kevlar fiber (WKF)-based flexible PTM device with a porous Ag@MoxFe1−xSe nanostructure (NS) between a substrate of WKF and Ti3C2 MXene film dispersed in polydimethylsiloxane (PDMS). Effective thermotherapeutic ability is demonstrated by the composite (80 °C at 3 V through Joule heating). The porous NS between the WKF and MXene/PDMS layers selectively reflected mid-infrared radiation (97.4%) and absorbed UV–vis–NIR (87.1%). The PTM increased the silicone heater temperature by 10 °C in an indoor setting; in direct sunlight, it raised the heater temperature by 20 °C demonstrating its passive and solar heating-mode. The fabricated device harvests energy from human body movements and simulated raindrops, exhibiting high self-powered heating efficiency and has a maximum power density of 1.5 mW cm−2 at low frequency (5 Hz). The WKF/Ag@MoxFe1−xSe/MXene/PDMS displayed high tensile strength, excellent breathability and durability. This work demonstrates the advantages of this multifunctional energy-reducing device addressing the world energy crisis, which is effective both indoors and outdoors in cold climates, and in sunny and rainy weather.

Investigation of Terahertz Cathode Heated by Electron Beam

An electron beam heating model capable of heating terahertz (THz) cathode has been developed. The cathode temperature field was simulated, which showed that both the heat radiation of the THz heater and the electron beam bombardment made contribution to heating the THz cathode. Experimentally, the emission capacity of the THz heater made of tungsten-thorium filament was investigated at different temperatures. The dependences of the cathode temperature on the bombardment power <inline-formula> <tex-math notation="LaTeX">$P$ </tex-math></inline-formula> or the THz heater temperature <inline-formula> <tex-math notation="LaTeX">$T_{h}$ </tex-math></inline-formula> were studied, respectively. The cathode temperature can reach 1098 &#x00B0;C at <inline-formula> <tex-math notation="LaTeX">$P$ </tex-math></inline-formula> of 3.98 W and <inline-formula> <tex-math notation="LaTeX">$T_{h}$ </tex-math></inline-formula> of 1725 &#x00B0;C. The warm-up time of the THz cathode was investigated, and the cathode temperature became stable at 1100 &#x00B0;C in 27 s.

60 Running Water While Bathing Is a Risk Factor for Pediatric Scald Burns

IntroductionScalds are the most common mechanism of burn in children, and a significant proportion of these injuries are associated with bathing. Burns sustained while bathing present a unique opportunity for injury prevention; previous studies have examined lowering water heater temperatures, however reputable infant bathing educational resources do not explicitly recommend avoiding running water and the risks that it could pose. In an effort to inform prevention programs, this study seeks to determine the incidence and circumstances of running water in bathing scald burns at our institution.MethodsA retrospective review was performed of records from an American Burn Association verified center over a ten year period (1/1/2010 to 12/31/2019). This center treats both children and adults and is affiliated with an academic hospital in a major urban center. The burn database was queried for scald injuries in children less than three years involving bathing. The Child Advocacy and Protective Services team provides inpatient consultation for all children less than three years old with burn injuries allowing us to analyze the specific events surrounding the bathing scald burns in this cohort.ResultsA total of 123 patients met inclusion criteria. Three bathing safety risk factors were specifically noted in the chart review: (1) running water, (2) lack of caregiver presence for duration of bathing, and (3) failure of caregiver to check water temperature before bathing. Of the cases identified, 107 (87%) had clear documentation of running water as part of the history of injury, 66 (54%) cases involved failure of caregiver to check the water temperature before bathing and 53 (43%) cases did not have a caretaker present for the duration of the bath. In cases with only one risk factor, running water was identified in 34 (94%) out of 36 cases, and in cases with one or two risk factors, running water remained the primary risk factor with 38 (90%) out of 42 cases. When looking at the combination of risk factors, only three (2%) cases had no risk factors while 77 (63%) involved two or more risk factors.ConclusionsThe vast majority of bathing burn injuries in this series involved running water. In addition, a significant number of scald burns occurred from running water alone, even without the other identified risk factors. Conversely, only 2% of scald burns associated with bathing featured none of these three risk factors, suggesting that these injuries could be greatly impacted by safe bathing education.

The Positive Temperature Coefficient of Resistivity in BiFeO3 Films

The use of lead-free ceramic film materials with positive temperature coefficient of resistivity (PTCR) is widespread in temperature heaters and sensors in micro-electromechanical systems. In this research, the out of plane transport properties of the BiFeO3 (BFO) films have been studied. Surprisingly, PTCR was found in the BFO ceramic films due to the strongly correlated interaction between the multiferroic material BFO and the superconductor YBCO perovskite oxides. To our knowledge, this is the first report on the PTCR effect of BFO films. The BFO/YBCO interface and the bulk conductivity of BFO are important for the PTCR effect, as they make it possible to compare the transport properties of Au/BFO/YBCO- and YBCO/BFO/YBCO-type structures. PTCR was observed in Au/BFO/YBCO at a bias voltage of more than 2 V, but not in the YBCO/BFO/YBCO, even with a 40 V bias voltage. PTCR was found after BFO breakdown of a YBCO/BFO/YBCO capacitor. This indicated that the conductivity of BFO is critical for PTCR. The dependence of PTCR on the superconducting transition temperature illustrates that a cooper-pair can be injected into BFO. Our work presents a method by which to produce a lead-free ceramic film material with PTCR.

Determination of trace genotoxic impurities in nifedipine by ultra high performance liquid chromatography-electrostatic field orbitrap high resolution mass spectrometry

建立了测定硝苯地平中基因毒性杂质2、6和12的超高效液相色谱-静电场轨道阱高分辨质谱法(UHPLC-Orbitrap HRMS)。样品以甲醇为溶剂,提取后直接进样分析。采用ACE EXCELTM 3 C18-AR色谱柱(150 mm×4.6 mm, 3 μm)分离,流动相为甲醇-0.1%甲酸水(65:35, v/v),等度洗脱。质谱部分采用电喷雾电离(ESI)源。采用正离子平行反应监测(PRM)扫描模式,质谱分辨率为35000 FWHM,杂质2、6、12的[M+H]+母离子准确质量数分别为m/z 347.1230、361.1026、347.1230,提取[M+H]+碎片离子准确质量数分别为m/z 315.0968、298.1069、315.0968,归一化碰撞能量(NCE)分别为10%、42%、10%,外标法定量。对方法进行了详细的方法学验证,结果表明,该法专属性良好,溶剂对杂质测定无干扰;杂质2、6、12质量浓度与其峰面积在0.2~100 ng/mL范围内呈现良好的线性关系,相关系数(r)均≥0.9998;杂质2、6、12在低、中、高3个水平下的回收率为96.9%~105.0%, RSD为1.21%~5.12%,检出限均为0.05 ng/mL,定量限均为0.2 ng/mL。应用该方法对3批硝苯地平样品中的杂质2、6、12进行测定,3批样品均未检出杂质6,但均检出杂质2和杂质12,其检出量未超过限度。该方法灵敏、快速、准确,操作简便,可为药企对硝苯地平的质量控制提供参考,并为药监部门的监管提供有力的技术支持。

Pool boiling enhancement via nanotexturing and self-propelled swing motion for bubble shedding

Vapor bubbles were shed from the heater surface by self-propelled swinging resulting from rising bubbles for improved heat dissipation. The heating wire was electroplated, and thus nanocones were formed on its surface. This nanotextured wire was attached to polyamide tape and underwent Joule heating. The vapor bubbles on the wire induced the self-propelled motion of the heater plates assembled in a “Λ” shape suspended at the tip. The growing bubbles experienced competing forces in the form of buoyancy and surface tension. Eventually, buoyancy dominated and, as a result, the heater plate was propelled in the direction of the rising bubbles. The nanotextured surface increased the number of bubble nucleation sites, and thus, the displacement of the swing motion was magnified accordingly, owing to enhanced bubble detachment. The sustainable swing motion was motorized to enable the temperature of the wire heater to be accurately measured. In these motorized experiments, the critical heat flux (CHF) and effective convective heat transfer coefficient (heff) increased when the amount of nanotexturing on the heating wire increased, which confirmed the benefits of nanotexturing on pool boiling in which self-propelled swing motion was utilized to shed the nucleated bubbles.

Energy Harvesting With Thermally Induced Vibrations in Shape Memory Alloys by a Constant Temperature Heater

This article reports a theoretical and experimental study of a novel thermal energy harvester with heat-induced vibrations in an environment with a nonzero temperature gradient. The energy harvester comprises a shape memory alloy wire from Nitinol and two elastic cantilever beams with deposited lead zirconium titanate piezoelectric layers. The shape memory alloy wire is prestrained by the free ends of the cantilever beams connected in a bow-similar structure. The environment temperature gradient is obtained from the difference in temperatures of a heater and colder air in the room. When the wire approaches the heater, it heats up and shortens, causing it to move away from the hot zone and entering into a colder zone. This causes the wire to cool and to approach the heater again. The cyclic change of the length of the shape memory alloy wire causes vibrations in the cantilever beams due to which electricity is produced by the piezoelectric layers. A dynamical model, based on the theory of Lagrange and Maxwell, combining mechanical, piezoelectric, and thermal domains is derived and used to prove the concept of the developed novel device and for theoretical investigation of the energy harvester performance. The hysteretic behavior of the shape memory alloy is involved in the model. The theoretical results have been proved experimentally.

Design, Manufacturing and Testing of a Stirling Engine with Slider-Crank Mechanism

In this study, a beta type Stirling engine with slider-crank mechanism having swept volume of 365 cm3 was designed, manufactured and performances tested. The design phase was first started by determining the operating parameters of the engine. The necessary mathematical calculations were performed by considering the operating conditions of the Stirling engine with a slider-crank mechanism to be manufactured. After determining the engine parameters, the dimensional design phase was started within the tolerance limits of the engine parts. The parts were designed by the computer-aided SolidWorks program in solid modeling and by the AutoCAD program in two-dimensional design and projecting. Each part used in the manufacturing of the Stirling engine was assembled delicately in the assembly process. A prony-type dynamometer, liquefied petroleum gas (LPG) fuel, and electronically controlled electric heater systems were developed to perform the performance tests and analyses of the manufactured engine. Experimental studies were conducted at hot end temperatures of 627 °C, 727 °C, and 827 °C and at a cold end temperature of 27 °C by utilizing an electrical heater as a heat source and air as a working fluid. According to the results obtained in experimental studies for different heater temperatures and different charge pressures, it was revealed that engine power values increased depending on the heater temperature and charge pressure increase. The maximum power values at all heater temperatures were acquired at a charge pressure of 4 bar. In this study, the maximum engine power was obtained as 69.5 W at a hot end temperature of 827 °C, at a charge pressure of 4 bar, and at an engine speed of 200 rpm when a stainless-steel displacement piston and air as a working fluid were utilized, and the maximum engine torque value was obtained as 4.21 Nm at a charge pressure of 4 bar and an engine speed of 135 rpm. The lowest engine power among the maximum engine power values obtained in all experimental studies was found as 17.09 W at a hot end temperature of 627 °C, at a pressure of 1 bar, and at an engine speed of 185 rpm. The maximum power values of the engine developed within the scope of this study at hot end temperatures of 627 °C, 727 °C, and 827 °C were determined to be 31.2 W, 48.3 W, and 69.5 W, respectively. Upon examining the results obtained from experimental studies, it is observed that the heater temperature and charge pressure have significant impacts on the performance values of Stirling engines. Within the scope of this study, a new power generation system that could use renewable energy sources was put into operation.

Development of a Performance Analysis Model for Free-Piston Stirling Power Convertor in Space Nuclear Reactor Power Systems

Space nuclear reactor power system (SNRPS) is a priority technical solution to meet the future space power requirement of high-power, low-mass, and long-life. The thermoelectric conversion subsystem is the key component of SNRPS, which greatly affects the performance, quality, and volume of SNRPS. Among all kinds of proposed thermoelectric conversion technologies, the free-piston Stirling power converter (FPSPC) has become a preferred conversion technology for small-scale advanced SNPRS due to its moderate waste heat emission temperature and high conversion efficiency, mainly composed of a linear alternator and free-piston Stirling engine (FPSE). For studying the performance of FPSPC, a quasi-steady flow thermodynamic cycle analysis model considering parasitic heat losses has been developed for FPSE. And then the performance analysis model for FPSPC has been established by coupling the thermodynamic cycle analysis model with the mechanical motion model of the piston and volt-ampere characteristic model of the linear alternator. Furthermore, the analysis model was compared and validated by the GPU-3 Stirling engine’s experimental data. The performance parameters of Component Test Power Converter (CTPT) FPSPC designed by NASA for SNRPS were also analyzed. The results show that the amplitudes position of CTPC displacer and piston are 15.1 mm and 11.2 mm, respectively. The corresponding average electric power output of CTPC is 17.316 kW. The input thermal power to the CTPT heater is 66.1 kW, leading to the converter efficiency of 26.2%. The average current and voltage of the CTPC alternator are 86.38 A and 193.15 V, respectively. Among all kinds of parasitic energy losses, the regenerator heat loss accounts for the largest proportion, with an average of about 12.7 kW. The effects of cooler and heater temperature on the performance of CTPC FPSPC were also studied.

Experimental investigation on the characteristics of film thickness and temperature on the heated surface during spray cooling

The heat dissipation problem has become a new challenge for improving the comfort of the built environment. Spray cooling, as an efficient heat exchange technique, attracts more attention. In the present study, an experimental work was performed to investigate the influence of the liquid film produced by a pressure-swirl nozzle on the heat transfer in spray cooling. The film thickness and heated surface temperature at different water flow rates (100–160 ml/min), spray heights (2–10 mm) and temperature of heaters (0–140 °C) were studied. The experimental results indicated that the water film was not flat, and a raised zone was formed under the pressure-swirl nozzle. The time-average film thickness of the raised zone first increased and then decreased with the increase of spray heights. Besides, the amplitude of the water film became larger with the temperature of heaters, and the maximum thickness was 3.82 mm. The heat transfer under experimental conditions was located in the non-boiling region. The non-uniformity of the temperature distribution became more significant with the temperature of heaters, and the maximum standard deviation was 4.66 °C. Besides, the main heat transfer mechanism inside the raised zone was the droplet impingement instead of the raised zone’s collapse when spray heights were more than 6 mm, and the heat outside of the raised zone was mainly removed by the film convection. The experimental findings are conducive to further study on the heat transfer under spray cooling.

Accelerating Upstream Together: Achieving Infant Health Equity in the United States by 2030.

Accelerating Upstream Together: Achieving Infant Health Equity in the United States by 2030.

A hydrogen generator coupled to a hydrogen heater for small scale portable applications

This study aims to build and test a small scale portable device able to couple a hydrogen generation system (based on a NaBH4 solution as liquid H2 carrier) to a hydrogen heater (based on the exothermic catalytic combustion of the released H2). The hydrogen generating system is based on the hydrolysis of stabilized solutions of NaBH4 (fuel solutions) which are pumped into the hydrolysis reactor. The generated H2 feeds the catalytic combustor. Two catalysts have been developed for the H2 generation and the combustion reactions able to operate at room temperature without need of additional energy supply. For the NaBH4 hydrolysis a Co-B catalyst was supported on a perforated and surface treated stainless steel (SS316) home-made monolith. For the flameless H2 catalytic combustion a Pt catalyst was prepared on a commercial SiC foam. The device was automatized and tested for the on-demand production of heat at temperatures up to 100ºC. In steady state conditions the NaBH4 solution flow is controlling the H2 flux and therefore the heater temperature. Once the steady-state is reached the system responds in a few minutes to up and down temperature demands from 80 to 100 ºC. The catalysts have shown no deactivation during the tests carried out in several days.

Design and development of heater control circuit without temperature sensor for monitoring hydrogen in argon.

A thin film based tin oxide sensor is developed to monitor low levels of hydrogen (concentration ranging from 5 to 75 ppm) in the cover gas plenum of the fast breeder test reactor. The heater and the sensor patterns are integrated on a miniature alumina substrate, and necessary electrical leads are incorporated into it. For proper functioning of the sensor, the heater has to be maintained at a constant temperature of 350 °C. This paper gives an outline of the electronics developed to measure the sensor signal and to control the heater temperature. The major challenge in this work is that there was no provision for embedding a temperature sensor on the heater surface due to physical constraints. This constrained the maintenance of a constant heater temperature for the proper functioning of the sensor. This led us to develop and demonstrate a heater control circuit without a temperature sensor to maintain a fixed temperature for monitoring hydrogen in argon, and electronics for the above-mentioned circuitry is discussed.

Superhydrophobic graphene/ceramic templates for the preparation of particulate drugs

This paper proposes the use of superhydrophobic graphene/ceramic templates fabricated through laser texturing and patterning for the preparation of particulate drugs. A nanosecond pulse fiber laser was used to texture a graphene film coated on ceramic substrates for obtaining a superhydrophobic surface. Then, laser patterning was conducted on the laser-textured surface to define the diameter of the prepared particulate drugs. Laser-textured graphene/ceramic substrates with a laser areal fluence of 17.51 J/cm 2 and a hatch distance of 0.01 mm exhibited a maximum water contact angle of 151.5°. This result was obtained because the laser-textured graphene films contained coral reef structures with nanoscale pores. Raman analyses indicated that the intensities of the G and 2D bands gradually decreased after the laser texturing and patterning processes. Moreover, the sheet resistance of the laser-textured and laser-patterned graphene films was larger than that of untextured ones because the thickness of the graphene films was reduced through laser thinning. The maximum heating temperature of the graphene-based heater was 140 °C for an input direct current voltage of 36 V. In addition, graphene-based self-heating devices were developed and successfully used to dry liquid roflumilast.

Experimental investigation and exergy and energy analysis of a forced convection solar fish dryer integrated with thermal energy storage

&lt;abstract&gt; &lt;p&gt;Drying is an effective means of reducing post-harvest losses which increases the shelf life of products by reducing their moisture content to a safe storage level. An indirect mode forced convection solar dryer integrated with thermal energy storage was designed, developed and experimentally tested by drying fish. The components of the dryer are a double pass solar air heater, a paraffin wax-based shell and tube for latent heat thermal energy storage, a drying chamber and a blower. A maximum temperature of 69 ℃ was obtained at the outlet of the solar air heater, and the energy and exergy efficiencies were 25% and 1.5%, respectively. The latent heat storage reduces the fluctuations in the outlet temperature of the solar air heater and extends the drying process for two extra hours per day. The average energy and exergy efficiencies of the energy storage were 41.9% and 15.6%, respectively, whereas average energy and exergy efficiencies of the drying chamber were 35% and 52%, respectively. Moreover, 5 kg of fresh fish was effectively dried in the dryer within 21 hrs, reducing the moisture content of the fish from 75% to 12.5% by removing 3.57 kg of moisture. The specific energy consumption of the dryer was 7.3 kWh per kilogram of moisture, and the power consumed by the blower was 0.6 kWh per kilogram of moisture, which is 8.3% of the total energy consumption. The remaining 91.7% of the energy is harvested from the sun, and the overall efficiency of the drying system is 9.4%.&lt;/p&gt; &lt;/abstract&gt;

Development of a two-dimensional mathematical model of flow boiling heat transfer in micro- and minichannels

The paper concerns flow boiling heat transfer in micro- and minichannels. In the mathematical model, the steady state heat transfer process in a single asymmetrically heated minichannel was considered. Calculations with the use of Trefftz functions were based on the data from own experiments. The temperature of the heater and the refrigerant were assumed to satisfy the Laplace equations and the energy equation respectively. The problem was solved by the Trefftz method using two sets of Trefftz functions. The known heater and refrigerant temperature distributions were used to determine the heat transfer coefficient at the heater – refrigerant contact. To verify the proposed mathematical model, data from experiments were applied to calculations. The essential part of the experimental stand was the test section which comprises a minichannel heat sink. The heated element for Fluorinert FC-72 flowing along minichannels was a thin foil. The temperature of its outer side was measured using infrared thermography. Thermocouples and pressure transducers installed at the inlet and outlet of the test section monitored fluid temperature and pressure. Mass flow rate, the current supplied to the heater and the voltage drop were also recorded. The resulting graphs presented thermograms of measured temperature on outer surface of the heater, temperature distributions of fluid temperature and local values of the heat transfer coefficient.

Prospective cohort study of bedroom heating and risk of common cold in children.

In countries with mild winter climates and inadequate heating, the relationship between housing conditions and health outcomes in winter have not been well studied. The purpose of the present study was to evaluate the relationship between heater type and temperature factors in the bedroom and incidence of the common cold among children in Japan. In this prospective cohort study, we distributed baseline questionnaires and temperature loggers in December 2019 and administered follow-up questionnaires in March 2020. We recruited children under the age of 15 years. We performed Poisson regression analysis and logistic regression analysis. Of 297 participants, air conditioners were the most prevalent (n = 105, 35%), followed by gas or kerosene heaters (n = 50, 17%), and floor heaters (n = 31, 10%). Air-conditioners were associated with higher incidence of all events related to the common cold, especially having a fever (adjusted incidence rate ratio (aIRR) = 1.84, 95% confidence interval (CI): 1.41-2.40). Gas or kerosene and floor heaters showed a lower incidence rate of some events related to the common cold, such as school or nursery school absence (aIRR = 0.55, 95% CI: 0.37-0.82 and aIRR = 0.39, 95% CI: 0.23-0.67, respectively). Bedroom temperature did not show a positive association, but children who always felt cold showed a higher incidence of some events related to the common cold. Our findings imply that the heating approach and modal thermal comfort, such as location of heating appliances, humidity, airflow, and radiant heat, may be more important for the onset of common cold in children than bedroom temperature itself.

Analytical Study of a Solar Hybrid Air-conditioning System Assisted Solar Absorption Using R-410A for Refrigeration Applications

This research focuses on the design, modeling, and simulation of absorption solar air-conditioning systems. Key performance parameters are identified and optimized for maximum efficiency, and the system was simulated using climatic conditions in Thi-Qar, Iraq, providing a good trend for the system to meet domestic airconditioning needs, which has a direct effect on the angle of incidence of solar radiation. The results of solar collectors and their effective performance in saving energy and improving system efficiency were discussed, where the work was performed on a solar heater with an evacuated tube with an area of 1.8 m2. The rate of emitted solar radiation was equal to 1000 W/m2. The average heat load of the solar heater was provided at a rate of 0.190 kW to 1.291 kW. The experiment in this paper was conducted in two stages. First, the solar heater was connected in the first case before the compressor. The reported results showed an increase in energy savings with average heater temperatures rising to 25% to 55% of the total energy consumed in the cooling cycle per day. The gas was heated to temperatures ranging from 45 to 65◦C, while the cooling rate was constant at 3.43. Second, the solar heater was connected after the compressor in the second case. The solar heater provided a significant improvement in system performance factor with an average of 5.1 to 13 and energy amount ranging from 15% to 24% of the total energy consumed. It is noted that the cooling load improved from 3.43 to 5.54 kW. The rate of thermal heating in the second case was from 100 to 160◦C gradually. Finally, it is noted that the second case has a much greater service advantage and economic feasibility than the first, and the system has improved as a result of improving the amount of cooling load while reducing energy consumption and increasing the overall performance of the system factor resulting from the improvement of the special conditions of the coolant used in the (R-410a) cycle.