Designed Heating System Research Articles

Design and numerical simulation of a 45 kWel multi-source high-flux solar simulator as a heating source of dielectric materials positioned in a microwave characterization cavity

This study reports the design and modelling of a high-flux solar simulator (HFSS) combined to a resonant cavity for microwave dielectric properties characterization of ceramics at very high temperatures. The HFSS comprises seven xenon arc lamps with ellipsoidal reflectors, delivering a maximal electrical power of 6.5 kWel each. Positioned on a virtual sphere of around 1600 mm radius, the lamps provide concentrated irradiation heating on a sample positioned inside the resonant cavity. The propagation of the lamp’s irradiation to the sample and the cavity is simulated using Monte Carlo ray tracing method. An ANSYS Fluent finite volume method for solving the resulting multimode heat transfer and flow indicate a radiative flux reaching 1.84 MW m−2, and a sample temperature of approximately 1470°C with 10 % non-uniformity. These results suggest that the designed heating system and resonant cavity is suitable for conducting microwave dielectric properties characterization of refracting ceramic materials at high temperatures, addressing a gap in studies focusing on temperatures exceeding 1000°C.

ASSESSMENT OF THE OPERABILITY OF THE WATER HEATING SYSTEM, NOT RELEVANT TO THE PROJECT

When designing water heating systems, it is necessary to avoid unjustified use of excess equipment, exceeding diameters beyond the required values, etc. In reality, there are deviations from the project during installation, which lead to the need to revise the parameters of the system's operability. One of the cases is the replacement of pipelines of one diameter with another. Consideration of the prospects for the operation of such a heating system by example is the purpose of this work.
 For example, the water heating system in a residential 11-storey building in Brest (Belarus) built in 2019 is considered. The house has designed an apartment-by-apartment two-pipe horizontal water heating system with the installation of heat meters for each apartment. When installing the heating system, the apartment-by-apartment branches of the heating system were mounted with polyethylene pipelines with a diameter of 18×2,5 mm and 14×2 mm instead of the design 25×3,5 mm and 16×2 mm.
 To analyze the prospects for the functioning of the designed heating system, calculations of hydraulic resistances in the system at maximum coolant flow rates were performed, as well as their correlation with the parameters of the pumping equipment installed in the individual heating point.
 Calculations have shown that the installed pump is sufficient for the operation of the heating system with the actual diameters of the pipelines. Thus, the actually applied pipe diameters do not adversely affect the performance of the heating system in question.

Demonstration study on ground source heat pump heating system with solar thermal energy storage for greenhouse heating

In this study, a demonstration project of a ground source heat pump (GSHP) heating system with seasonal solar thermal energy storage (SSTES) and diurnal solar thermal energy storage (DSTES) is constructed for greenhouse heating. In the non-heating season, the SSTES overcomes the thermal imbalance of GSHP heating for agricultural greenhouses. While in the heating season, the DSTES undertakes part of the heating load of greenhouses, reduces GSHP heating electric energy consumption and improves the annual coefficient of performance of heating system COPsys,y. The experimental data illustrate that the soil temperature of ground heat exchanger (GHE) area is about 0.3 K higher than the initial soil temperature at the end of SSTES, and the COPsys,y of the proposed heating system is 14.3 % higher than that of bank control experiment. The above results demonstrate that the proposed heating system is favorable for greenhouses in cold regions. Further, coupling DSTES can reduce the rated capacity of GSHP and the total length of GHE tube for the newly designed heating system. In addition, the recommended values of two key operating parameters are given based on the experimental data. This study can shed a light on clean and efficient heating for greenhouses in cold regions and provide data support for related research.

Study of the thermal characteristics of the aluminum radiator ROYAL Thermo Evolution

The use of aluminum radiators in heating systems began with the foreign companies products such as Fondital Group, Global Radiatori, Ferroli, etc. There are now Russian aluminum radiators companies that adhere to European standards, for example ROYAL Thermo, Rifar. The thermal characteristics of radiators are usually specified by the manufacturer. However, they are not always confirmed in practice. This is due to the fact that radiator connecting method is not taken into account. In some technical data sheets, the power reduction factors are given depending on the difference between the average coolant temperature and the air temperature in the room. Therefore, the study of the influence of aluminium heating appliances connecting on its thermal characteristics is an actual task. The article presents the results of research of radiator of the ROYAL Thermo Evolution type, it was made on request from company specialising in heating systems design. It was found that the actual thermal power of one section varies in the range of 135 … 225 W, depending on the connection method of the radiator, the thermal power of the section declared by the manufacturer corresponds only to the diagonal «top-bottom» connection, the thermal power of the eight-section radiator with one-sided «top-bottom» connection is 12% higher than with a diagonal one. Studies show, when designing heating systems, it is necessary to take into account the connection method and the number of device sections.

Analysis of Smart Zone Heating in Different Heating Systems

The basic concept in the design of buildings with zero energy consumption is, in addition to high-quality thermal properties of the building envelope, also a correct and efficient system of heating and hot water preparation in residential buildings. One of the basic concepts when designing heating systems is a zone heating system. It is a system that brings effective regulation according to heating zones. In practice, the question sometimes arises as to whether zone regulation of individual rooms in small family houses is necessary. That is whether in such buildings, zone heating is not an unnecessary investment cost. In this paper, we analyze the effect of zone heating in two types of heat transfer systems on the internal operating temperature in the individual analyzed zones, which are interconnected by an internal partition structure. It is a verification that even in smaller spaces, zone heating has a significant potential for energy savings.

Optimization of the composition of the structure of heat sources as applied to the problems of the development of heating systems

The study outlines the concept of the structure of heat sources of developing heating systems and states the problem of searching through structures of heat sources of maximum redundancy for the optimal one. As one of the techniques of solving this problem, the authors propose to split the process of designing heating systems into multiple stages. Within the scope of the above-stated problem, the difficult part is the need to create an automated system to solve the entirety of problems arising at these stages and to reconcile them with each other. We provide a brief overview of the the available software package that we propose to integrate into the process of solving and we underline the complex nature of the interaction of individual software components between each other. The authors propose an approach in the form of the computational experiment setup that enables to consistently coordinate computational procedures with each other. The approach is based on the concept of the energy hub as its theoretical backbone, while in terms of the software implementation it is an instance of an automated information system.

Experimental assessment of indoor microclimate in a room which is heated by the combined use of an electric radiant panel and sectional heating device

Designing heating systems; it is necessary to pay significant attention to the microclimate; which will be provided by these systems on the operation stage. To evaluate the indoor microclimate six basic thermal comfort parameters are commonly used; namely; they are: temperature; relative humidity and velocity of the air; enclosures radiation temperature; activity level of people who currently residing the room and thermal resistance of clothes in which they are worn. All of the above listed thermal comfort parameters should be considered not as separate ones; but as a dynamically changeable integrated system which is sensitive to many factors; but first of all; to heating devices location; it's temperature level and heat transfer method. In this paper; given the results of experimental studies of room indoor microclimate; which were heated with a combination of two heating devices: water sectional radiator of a centralized heating system and electric infrared panel. Air temperature in the heated room was measured with thermocouples which were located in nine points in the room center at an altitude of 0.5; 1.5 and 2.5 m respectively. Also were installed thermocouples in geometric centers of all walls; floor and ceiling to take into account the radiation temperature impact. The heating devices influence on local microclimate parameters was evaluated by means of special temperature measuring rods which contain 8 temperature sensors located at a distance of 2.5 cm from each other. Based on the gathered data of temperature; relative humidity and air velocity; as well as the PMV and PPD statistics indexes graphical distributions in room volume built. The obtained results have been analyzed and ideas for further research were given.

Hydrophobicity Tuning by the Fast Evolution of Mold Temperature during Injection Molding.

The surface topography of a molded part strongly affects its functional properties, such as hydrophobicity, cleaning capabilities, adhesion, biological defense and frictional resistance. In this paper, the possibility to tune and increase the hydrophobicity of a molded polymeric part was explored. An isotactic polypropylene was injection molded with fast cavity surface temperature evolutions, obtained adopting a specifically designed heating system layered below the cavity surface. The surface topology was characterized by atomic force microscopy (AFM) and, concerning of hydrophobicity, by measuring the water static contact angle. Results show that the hydrophobicity increases with both the temperature level and the time the cavity surface temperature was kept high. In particular, the contact angle of the molded sample was found to increase from 90°, with conventional molding conditions, up to 113° with 160 °C of cavity surface temperature kept for 18 s. This increase was found to be due to the presence of sub-micro and nano-structures characterized by high values of spatial frequencies which could be more accurately replicated by adopting high heating temperatures and times. The surface topography and the hydrophobicity resulted therefore tunable by selecting appropriate injection molding conditions.

Теплопотери с перегретой части стены под радиатором

The issue of the complementary heat loses through the overheated wall is considered from several aspects. The calculations of convection and radiation heat exchange between outer wall and radiator is provided. The amount of the heat loses of radiator installed by the outer wall is compared with the loses of the one installed by interior wall. It is found that 30% of extra more heat can leak outdoors through the zone under radiator. Different reasons of the complementary heat loses are discussed. Problems of manufacturing radiators, designing heating systems and placing the heating devices is considered as reasons related to the heat loses. Set of recommendations is suggested in the current paper for decreasing and avoiding the amount of the loses.

MIP approach for designing heating systems in residential buildings and neighbourhoods

In this work, a mixed integer linear programming (MIP) approach for the optimal design of energy systems in residential buildings is presented. The optimization model considers the economic criteria of the guideline VDI 2067. The objective of the MIP is to minimize the annual costs which comprise the investment as well as demand- and operation-related costs. Conventional boilers, electrical heaters, combined heat and power (CHP) units, heat pumps (HPs), photovoltaic (PV) systems and thermal storages as well as local heating networks (HNs) are defined as options. The investigation on a building level shows that a boiler is the economically optimal solution for small buildings, followed by a HP unit. In multi-family buildings, both boilers and CHP units hold an economical advantage over HPs. For apartment buildings, CHP is identified as the economically optimal system. In the neighbourhood analysis of six buildings, the solver establishes a local HN which allows for both economical and CO2-emission reductions.

Dynamic Thermo-mechanical Response of Hastelloy X to Shock Wave Loading

A comprehensive series of experiments were conducted to study the dynamic response of rectangular Hastelloy X plates at room and elevated temperatures when subjected to shock wave loading. A shock tube apparatus, capable of testing materials at temperatures up to 900 °C, was developed and utilized to generate the shock loading. Propane gas was used as the heating source to effectively provide an extreme thermal environment. The heating system is both robust and capable of providing uniform heating during shock loading. A cooling system was also implemented to prevent the shock tube from reaching high temperatures. High-speed photography coupled with the optical technique of Digital Image Correlation (DIC) was used to obtain the real-time 3D deformation of the Hastelloy X plates under shock wave loading. To eliminate the influence of thermal radiation at high temperatures, the DIC technique was used in conjunction with bandpass optical filters and a high-intensity light source to obtain the full-field deformation. In addition, a high-speed camera was utilized to record the side-view deformation images and this information was used to validate the data obtained from the high temperature 3D stereovision DIC technique. The results showed that uniform heating of the specimen was consistently achieved with the designed heating system. For the same applied incident pressure, the highest impulse was imparted to the specimen at room temperature. As a consequence of temperature-dependent material properties, the specimen demonstrated an increasing trend in back-face (nozzle side) deflection and in-plane strain with increasing temperature.

Modelling and simulation of a hybrid solar heating system for greenhouse applications using Matlab/Simulink

Solar energy is a major renewable energy source and hybrid solar systems are gaining increased academic and industrial attention due to the unique advantages they offer. In this paper, a mathematical model has been developed to investigate the thermal behavior of a greenhouse heated by a hybrid solar collector system. This hybrid system contains an evacuated tube solar heat collector unit, an auxiliary fossil fuel heating unit, a hot water storage unit, control and piping units. A Matlab/Simulink based model and software has been developed to predict the storage water temperature, greenhouse indoor temperature and the amount of auxiliary fuel, as a function of various design parameters of the greenhouse such as location, dimensions, and meteorological data of the region. As a case study, a greenhouse located in Şanlıurfa/Turkey has been simulated based on recent meteorological data and aforementioned hybrid system. The results of simulations performed on an annual basis indicate that revising the existing fossil fuel system with the proposed hybrid system, is economically feasible for most cases, however it requires a slightly longer payback period than expected. On the other hand, by reducing the greenhouse gas emissions significantly, it has a considerable positive environmental impact. The developed dynamic simulation method can be further used for designing heating systems for various solar greenhouses and optimizing the solar collector and thermal storage sizes.

Rapid typing of influenza viruses using super high-speed quantitative real-time PCR

The development of a rapid and sensitive system for detecting influenza viruses is a high priority for controlling future epidemics and pandemics. Quantitative real-time PCR is often used for detecting various kinds of viruses; however, it requires more than 2h per run. Detection assays were performed with super high-speed RT-PCR (SHRT-PCR) developed according to a newly designed heating system. The new method uses a high-speed reaction (18s/cycle; 40 cycles in less than 20min) for typing influenza viruses. The detection limit of SHRT-PCR was 1 copy/reaction and 10−1 plaque-forming unit/reaction for viruses in culture supernatants during 20min. Using SHRT-PCR, 86 strains of influenza viruses isolated by the Tokyo Metropolitan Institute of Public Health were tested; the results showed 100% sensitivity and specificity for each influenza A and B virus, and swine-origin influenza virus. Twenty-seven swabs collected from the pharyngeal mucosa of outpatients were also tested, showing positive signs for influenza virus on an immunochromatographic assay; the results between SHRT-PCR and immunochromatography exhibited 100% agreement for both positive and negative results. The rapid reaction time and high sensitivity of SHRT-PCR makes this technique well suited for monitoring epidemics and pre-pandemic influenza outbreaks.

Nonstationary Heat Conduction in Complex-Shape Laminated Plates

Abstract Based on the immersion method, an analytical solution has been obtained for the problem of nonstationary heat conduction in laminated plates of complex plan shape when they are heated with interlayer film heat sources. The temperature distribution over the thickness of each layer is represented in the form of an expansion in a system of the orthonormal Legendre polynomials and, in the plate plane, it is represented as trigonometric series expansions. Temperature fields were investigated in a five-layer plate for conditions of convective heat exchange with the environment. The method suggested can be applied for designing heating systems and determining temperature stresses in laminated glazing for different vehicles

Development and application of a specially designed heating system for temperature-programmed high-performance liquid chromatography using subcritical water as the mobile phase

A specially designed heating system for temperature-programmed HPLC was developed based on experimental measurements of eluent temperature inside a stainless steel capillary using a very thin thermocouple. The heating system can be operated at temperatures up to 225 °C and consists of a preheating, a column heating and a cooling unit. Fast cycle times after a temperature gradient can be realized by an internal silicone oil bath which cools down the preheating and column heating unit. Long-term thermal stability of a polybutadiene-coated zirconium dioxide column has been evaluated using a tubular oven in which the column was placed. The packing material was stable after 50 h of operation at 185 °C. A mixture containing four steroids was separated at ambient conditions using a mobile phase of 25% acetonitrile:75% deionized water and a mobile phase of pure deionized water at 185 °C using the specially designed heating system and the PBD column. Analysis time could be drastically reduced from 17 min at ambient conditions and a flow rate of 1 mL/min to only 1.2 min at 185 °C and a flow rate of 5 mL/min. At these extreme conditions, no thermal mismatch was observed and peaks were not distorted, thus underlining the performance of the developed heating system. Temperature programming was performed by separating cytostatic and antibiotic drugs with a temperature gradient using only water as the mobile phase. In contrast to an isocratic elution of this mixture at room temperature, overall analysis time could be reduced two-fold from 20 to 10 min.

Ellipsometry of High Temperature Phase Transitions in PZT and (ZnLi)O Films

In this work, ellipsometric investigation of high temperature phase transitions in PbZr0.235 Ti0.765O3 (PZT) and (Zn0.7Li0.3)O thin films are presented. Ellipsometric measurements were performed by means of a J. A. Woollam spectral ellipsometer operating in rotating analyzer mode. The main ellipsometric angles Ψ and Δ were measured in the spectral range from 200 to 1200 nm. High temperature measurements were carried out with a specially designed heating system. The samples were heated up to 550°C. The temperature dependences of the refractive index and absorption coefficient at fixed wavelengths and the optical gap Eg were calculated from ellipsometric data. High sensitivity of ellipsometry allowed us to observe the well-known ferroelectric → paraelectric phase transition and to find a new phase transition in PZT films. High temperature measurements performed for (Zn0.7Li0.3)O films didn't confirm the ferroelectric phase transition at ∼70°C described in [1]. However, strong changes of ellipsometric parameters at 470°C and change of band gap temperature behavior at 300°C were found. The determination of the absorption gap temperature dependence near this temperature confirmed strong structural changes.

High Temperature Effects in Li-Doped ZnO Thin Films

In this work, we present ellipsometric investigations of low-pressure plasma jet sputtered (Zn0.5Li0.5)O thin films at high temperatures. Optical measurements were performed with the J. A. Woollam spectral ellipsometer operating in rotating analyzer mode. High temperature measurements were performed with a specially designed heating system that allowed samples to be heated up to 520°C. The temperature dependences of surface roughness and the optical gap Eg were obtained for both cooling and heating directions. We didn't find any evidence of ferroelectric phase transition at ∼70°C described in [1] but we have observed band gap and surface roughness jumps at 300°C and 450°C that is a strong evidence of structural changes at these temperatures.

High-Temperature Phases in PZT Ferroelectric Films

Ellipsometric investigations of the PbZr0.235Ti0.765O3 (PZT) films at high temperatures are presented in this work. High temperature measurements were performed with a specially designed heating system. The samples were heated up to 550°C to reach the paraelectric phase. The temperature dependences of the refractive index at fixed wavelengths were obtained for both cooling and heating directions. Refractive index depth profiles were calculated in all high-temperature phases.

Application of Multi-Criterion Decision Aid Method in Designing Heating Systems for Museum Buildings

The aim of the work is to chose the best heating system for a museum building. The paper presents the criteria describing this problem. The three technically acceptable heating systems have been identified. The method allowing for the multi-criterion analysis has been selected with the assumption that the final result will be a final ranking of all alternatives. The ELECTRE III method has been chosen. This method helped to solve the problem of pointing at the best heating system.

A New Method for Thermocholecystectomy

The authors tested the feasibility of thermocholecystectomy for gallbladder ablation in an animal model. Thermal treatment of the cystic duct followed by heating of the saline-filled gallbladder using a separately designed heater/expander was performed in 13 pigs (group I). In four animals, heating of the gallbladder alone was performed (group II). Two animals served as controls (group III). All animals were killed 12 weeks after treatment. There was cystic duct occlusion in 10 (77%) of 13 of group I animals. In 6 (60%) of 10 of these animals with cystic duct occlusion, there was complete ablation of the gallbladder mucosa and complete obliteration of the gallbladder lumen. In group II animals, all cystic ducts were intact with an unchanged gallbladder volume in all four animals (100%), and normal gallbladder mucosa were intact in three (75%) of four animals. The gallbladders and cystic ducts in group III animals were normal. This study demonstrates many technical difficulties with thermal cholecystectomy. However, under ideal conditions, permanent gallbladder ablation is feasible in our animal model using a specially designed heating system.