scholarly journals Experimental research of electrical characteristics combined solar-electric air heater

2021 ◽  
Vol 36 ◽  
pp. 15-20
Author(s):  
P. Pasichnyk ◽  
К. Gaba ◽  
М. Kyrychenko
Keyword(s):  
Solar System ◽  
Electric Current ◽  
Electrical Resistance ◽  
Knitted Fabric ◽  
Electrical Characteristics ◽  
Solar Collectors ◽  
Heating Systems ◽  
Textile Materials ◽  
Capital Costs ◽  
Air Heater

The development and improvement of solar equipment is a necessary step in the development of solar heating systems. One of the ways to develop solar air heaters is to use new materials for the production of solar absorbers. This expands the possibility of using nozzle and capillary-porous materials in contrast to liquid solar collectors. Development and research of air heating systems with equipment made of modern textile materials is relevant. For the manufacture of absorbers it is advisable to use textile materials. This will reduce the cost of solar collectors, as well as reduce their weight and capital costs. The absorber meets requirements for both solar thermal collectors and electric heaters: high absorption capacity of solar radiation; developed heat transfer surface; relevant physical properties: low mass, resistance to ultraviolet radiation, thermal resistance, low cost for cheaper solar system; sufficient electrical resistance. A combined solar-electric air heater has been developed, which combines two main elements of any solar system – a solar heat collector and an additional heat source, the absorber of which is made of carbon graphite knitted fabric. This reduces its cost and mass and allows them to be used on existing heating facilities without the construction of bulky supporting structures to accommodate solar fields. The combined solar-electric air heater can be used as an independent heat generator for heat supply systems. To use the proposed solar-electric air heater, it is necessary to heat its absorber with an electric current, so the material from which it is made must be electrically conductive, but have sufficient electrical resistance. The use of carbon-graphite knitted fabric allows the use the direct heating of the solar energy absorber by electric current due to the corresponding electrical characteristics. This article presents the results of an experimental study of the electrical resistivity of carbon-graphite knitted fabric. These studies allow determining the electrical power of the device regardless of the size of the device. The research results presented in the article can be used only for a certain type of carbon graphite knitted fabric.

Design, Analysis and Construction of a Low Cost Air Heater for Residential Uses

2015 ◽  
Author(s):  
Bernd Weber ◽  
Jessica A. Fernández Valdespino ◽  
David García ◽  
M. Dolores Durán ◽  
Iván G. Martínez Cienfuegos ◽  
...  
Keyword(s):  
Solar System ◽  
Energy Demand ◽  
Low Cost ◽  
Space Heating ◽  
Solar Air Heater ◽  
Sustainable Buildings ◽  
Heating Systems ◽  
Solar Systems ◽  
Air Heater ◽  
Global Challenges

In order to meet global challenges to reduce greenhouse gas emissions, the implementation of solar systems for residential purposes is an emergent task. Commonly liquid-based solar systems are used to heat up shower and pool water. More recently space heating systems have become part of sustainable buildings. An alternative could be a solar system that uses air as energy carrier. This study analyses the retrofit of such a system into a 40-year-old building. Starting from the analysis of the energy demand of a selected room, a solar air heater was designed, simulated and evaluated experimentally. The solar efficiency of the constructed collector reached 60%.

scholarly journals The Impact of Elongation on Change in Electrical Resistance of Electrically Conductive Yarns Woven into Fabric

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3390
Author(s):  
Željko Knezić ◽  
Željko Penava ◽  
Diana Šimić Penava ◽  
Dubravko Rogale
Keyword(s):  
Mathematical Model ◽  
Electrical Resistance ◽  
Electrically Conductive ◽  
Textile Materials ◽  
Measurement Results ◽  
Conductive Yarns ◽  
Yarn Count ◽  
As Relationship ◽  
The Impact ◽  
The Mathematical Model

Electrically conductive yarns (ECYs) are gaining increasing applications in woven textile materials, especially in woven sensors suitable for incorporation into clothing. In this paper, the effect of the yarn count of ECYs woven into fabric on values of electrical resistance is analyzed. We also observe how the direction of action of elongation force, considering the position of the woven ECY, effects the change in the electrical resistance of the electrically conductive fabric. The measurements were performed on nine different samples of fabric in a plain weave, into which were woven ECYs with three different yarn counts and three different directions. Relationship curves between values of elongation forces and elongation to break, as well as relationship curves between values of electrical resistance of fabrics with ECYs and elongation, were experimentally obtained. An analytical mathematical model was also established, and analysis was conducted, which determined the models of function of connection between force and elongation, and between electrical resistance and elongation. The connection between the measurement results and the mathematical model was confirmed. The connection between the mathematical model and the experimental results enables the design of ECY properties in woven materials, especially textile force and elongation sensors.

scholarly journals An experimental study of the thermal performance of the square and rhombic solar collectors

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 487-494 ◽  
Author(s):  
Aminreza Noghrehabadi ◽  
Ebrahim Hajidavaloo ◽  
Mojtaba Moravej ◽  
Ali Esmailinasab
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Solar Collectors ◽  
Heating Systems ◽  
Solar Water Heating

Solar collectors are the key part of solar water heating systems. The most widely produced solar collectors are flat plate solar collectors. In the present study, two types of flat plate collectors, namely square and rhombic collectors are experi?mentally tested and compared and the thermal performance of both collectors is investigated. The results show both collectors have the same performance around noon (?61%), but the rhombic collector has better performance in the morning and afternoon. The values for rhombic and square collectors are approximately 56.2% and 53.5% in the morning and 56.1% and 54% in the afternoon, respectively. The effect of flow rate is also studied. The thermal efficiency of rhombic and square flat plate collectors increases in proportion to the flow rate. The results indicated the rhombic collector had better performance in comparison with the square collector with respect to the mass-flow rate.

scholarly journals Вплив параметрів адитивного формування на електричні властивості графітонаповненого композиту на основі полілактиду

2021 ◽  
Vol 150 (5) ◽  
pp. 93-102
Author(s):  
Н. В. Сова ◽  
О. О. Слепцов ◽  
Т. Р. Федорів ◽  
А. О. Мартиненко ◽  
М. Р. Кудлай ◽  
...  
Keyword(s):  
Electrical Properties ◽  
3D Printing ◽  
Electrical Resistance ◽  
Specific Resistance ◽  
Polymer Melt ◽  
Electrical Characteristics ◽  
Additive Production ◽  
Filled Composite ◽  
Printing Parameters ◽  
Bulk Electrical Resistance

Purpose. Investigate the effect of additive formation parameters on the properties of an antistatic composition based on polylactide (PLA). Methodology. Surface and bulk electrical resistance were determined by ASTM D257. Findings. The influence of additive formation parameters on the electrical properties of graphite-filled composite based on polylactide has been studied. It was found that the value of resistivity significantly depends on the printing conditions, namely the temperature, speed, thickness of the layer. Increasing the printing temperature helps to reduce the resistivity of the sample. Reducing the thickness of the polymer layer also reduces the resistivity at a print speed within 3000 mm / min It was found that the specific electrical characteristics are significantly different in the plane of the sample in contact with the printing platform. Concentric method of laying layers of polymer melt is less effective in terms of resistivity than mutually perpendicular. It was found that the electrical resistivity of samples made of material for 3D printing, which was previously subjected to drying below the resistance of the sample made of undried material. The programmed change of 3D printing parameters allows to control the specific resistance of graphite-filled composite based on polylactide in the range of three orders and to obtain products with properties from antistatic to statically dissipative materials. Additive production allows to obtain products of the desired configuration with adjustable electrical properties. Originality. The peculiarities of the change of antistatic properties of the polymer composite depending on the conditions of additive formation of experimental samples are investigated. Depending on the applied parameters of additive molding, it is possible to obtain products with properties from antistatic to statically dissipative materials. Practical value. Technological modes of additive molding of composite products based on polylactide and graphite have been developed. Energy consumption for additive formation of products of different mass is estimated.

scholarly journals Resistivity behavior of leather after electro-conductive treatment

2019 ◽  
Vol 2 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Aulon Shabani ◽  
Majlinda Hylli ◽  
Ilda Kazani ◽  
Pellumb Berberi
Keyword(s):  
Electrical Resistivity ◽  
Environmental Conditions ◽  
Electrical Resistance ◽  
Chemical Processes ◽  
Bulk Conductivity ◽  
Measuring Cell ◽  
Textile Materials ◽  
Multiple Factors ◽  
Conductive Properties ◽  
First Time

Measurement of electrical resistance of textile materials, fiber and fabrics included, remains always an engaging task due to sensitivities to interference of multiple factors. Difficulty stands on both finding a method of measurements that fits the requirements of samples to be tested and the most appropriate indicator describing this property. Numerous methods and indicators are used for different sample content and shape (fibers, roving, yarn or fabric, etc.), even when the material tested is the same. Different methods usually use indicators that produce results difficult to compare or to interpret, or do not express intrinsic qualities of their constituent materials. The situation is the same for leather materials. In this paper, we propose a new method, multiple steps method, and a new indicator, electrical resistivity, which takes into consideration compressional properties of leather sample and produce results independent from the amount and form of the sample. Electrical resistivity of conductive leather, as defined below, is shown to be an inherent indicator of bulk conductivity of leather assembly and is not influenced by sample form or the way it is placed within the measuring cell. The method is used for the first time to evaluate changes in electrical resistivity of leather after various chemical processes to make it electro-conductive. The data provide important information about the evolution of electro-conductive properties of leather at different stages of processing, as well as the influence of environmental conditions.

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