New modifications will make it more efficient and environmentally friendly
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Ekaterinburg, Russia -- Scientists from Ural Federal University and Karaganda State Technical University simulated the work of an electric-hydrodynamic heater (EHDH) and proposed a method for its improvement. The resulting installation, which dimensions range from 0.8×1×1 m to 1.5×2×2.5 m, can be used in autonomous heating, hot water and air conditioning systems. The installation is environmentally friendly and easy to maintain; it allows consumers to set their own mode of operation. The results of the study are published in the journal Energy Procedia.
‘This is one of the prospective options for decentralized heat supply based on nonconventional energy sources,’ added one of the authors, Professor of Karaganda State Technical University Joseph Breido.
The electric-hydrodynamic heater converts electricity first into mechanical energy (pressure developed by a pump), then into hydraulic energy (energy of the moving working liquid) and, as a result, into thermal energy. The authors of the article focused their attention on the stage of converting mechanical energy into thermal energy. In order to be able to calculate the various parameters of the operation of such a system, it is necessary to carry out a number of measurements: temperature, pressure, fluid velocity. The mathematical model makes it possible to simplify and reduce the cost of this work. The scientists tested model's adequacy in the process of experimental studies of the
The structural elements of the EHDH are designed to support circulation of the working liquid (water) in a closed heat-generating contour. During this process, the cavitation effect (formation and collapse of gas bubbles in the liquid flow) appears in the tubular reactor in the structural element "Cavitator". As a result, we can observe the greatest increase in the temperature of the working fluid in the installation’s contour. The design of the "Cavitator" is a know-how of the researchers and is protected by patents. Simulation has shown that 80 to 90% of the energy consumed by EHDH converts into thermal energy.
On the basis of experimental measurements, scientists compiled 3D models of the working liquid’s movement inside the installation. Such models allow to find boundary conditions for solving physical and mathematical problems. When visualizing liquid flows, the researchers used standard physical models of the gas and liquid motion and complex calculations of temperature change and energy transfer. The models made it possible to specify various parameters: temperature, pressure, flow rate, liquid properties and initial temperature of the installation. Comparison of the calculated indicators with the results of the experiments confirmed the accuracy of the program and its suitability for the study of fluid flow and equipment design.
‘In the process of experimental research, we also set and solved the task of assessing the effect of the rotation speed of the frequency-controlled electric drive of a pumping unit on the performance characteristics of the EHDH and on energy consumption in obtaining thermal energy sufficient for comfortable autonomous heat supply and hot water supply of residential and office premises’, said Anatoly Zyuzev, co-author of the work, Professor of the UrFU Electric Drive Department.
The obtained results allowed the scientists to propose changes in the design of the EHDH that will make it more efficient. First of all, these improvements relate to the "Cavitator" and the vortex tube. For example, the change in the size of the “Turbine” blades, located in front of the "Cavitator", from six to eight cm allows to achieve a significant increase in the intensity of cavitation and, consequently, a rise in temperature.