TThe analysis of the heat exchange efficiency of the nanofluid "γ-alumina water" in the Slinky horizontal collector of the heat pump.
Students Name: Shyika Ivan Olehovych
Qualification Level: magister
Speciality: Heat and Power Engineering
Institute: Institute of Power Engineering and Control Systems
Mode of Study: full
Academic Year: 2022-2023 н.р.
Language of Defence: ukrainian
Abstract: Shyika I.O., Rymar T.I. (supervisor). Analysis of heat exchange efficiency of nanofluid "water - ?-alumina" in the Slinky horizontal collector of the heat pump. Master’s thesis. – Lviv Polytechnic National University, Lviv, 2022. Extended abstract Nowadays, in industry, the use of various nanotechnologies is becoming more and more widespread. In the world, in the field of energy, nanofluids are increasingly being used. Modernization and installation of heating systems require the use of new technologies. This is explained by the need to save electricity, gas, coal, as well as the ecological factor, since the problem of ecology is in the first place in our time. Human use of hydrocarbons negatively affects the ecological system, and we need to reduce the amount of carbon dioxide that is released when hydrocarbons are burned. The use of nanofluids in heat supply systems will reduce the amount of burning coal. Nanofluids are suspensions that consist of a liquid with the addition of nanoparticles with a size of less than 100 nanometers. The basic liquids for the development of nanofluids are: oil, water, ethylene glycol, diesel. Many experiments have shown that liquids containing nanoparticles have a much higher thermal conductivity compared to ordinary liquids. Nanoparticles are solid-liquid materials that consist of solid nanofibers or nanoparticles ranging in size from 1 to 100 nanometers. A nanofluid is not a simple mixture, the most important criterion of a nanofluid is a stable suspension without any formation of agglomerates for a long period of time, which does not cause any chemical reactions and changes in the base fluid. This is achieved by reducing the density between the liquid and the solid, or by increasing the viscosity of the substance. To avoid particle settling, nanometer-sized particles are used and their agglomeration is prevented. The most common nanoparticle that scientists use for their experiments is aluminum oxide (Al2O3). This nanoparticle is environmentally friendly, which plays an important role in the modern world. This is a promising use of them as heat carriers in heat supply systems of residential buildings and commercial enterprises. Due to their greater thermal properties, nanofluids are attractive for increasing the heat exchange efficiency of various heat supply systems, and this, in turn, affects the cost-effectiveness of the system as a whole. An increase in thermal conductivity is observed in these liquids due to the presence of nanoparticles in the liquid. This significantly improves heat transfer. As you know, the efficiency of the installations in the heating system of the house depends significantly on the efficiency of the system as a whole. Moreover, the design of modern heat supply systems is impossible without solving the problem of intensification of heat exchange. Therefore, scientific developments in this direction are negative and relevant today. The use of nanofluids in a modern heating system based on geothermal heat pumps helps to reduce the amount of electricity consumed by the pump, as well as to increase the amount of heat extracted from the air, soil, water, and this, in time, allows us to save on the cost of electricity and pay off the heat supply system faster. Water-to-water heat pumps are best suited for the use of a heat carrier with nanoparticles in them, since they take heat from water, which in turn is an uninterrupted source of heat supply. For example, if we take a river, the water in it circulates year-round and freezes only on the surface, and the temperature of the water closer to the bottom, in winter, always fluctuates around +2 degrees Celsius. This allows us to receive heat from the reservoir all year round, and the coolant with nanoparticles that circulates in our Slinky collectors will help to extract the maximum amount of heat from our reservoir. At the same time, in the summer, from the same reservoir, with the help of a coolant with nanoparticles, we will be able to take the maximum amount of cold, which will passively, without causing any damage to our respiratory tract, cool the house. Since, passive heating/cooling is heating/cooling of the structure of the house itself, that is, we do not have to deal with the mixing of air flows that occur when using an air conditioner/fan coil, which in turn is very good for our health [1, 2]. Study object – thermal processes of the river horizontal collector Slinky heat pump heat supply system of the energy-independent house. Scope of research – methodical approaches to solving the problems of calculation substantiation of increasing the efficiency of the heating system of a house with a river horizontal collector Slinky heat pump due to the use of dispersed nanofluid from ?-alumina as a heat carrier. Goal of research: study of the coefficients of the use of aqueous dispersion with nanoparticles of ?-alumina (Al2O3) with three high concentrations of nanoparticles in heat supply systems. In order to achieve the set goal, the following tasks were identified in the master’s work: - review and analysis of scientific works by research topic; - development of a heat supply system for an energy-independent house with a Slinky heat pump horizontal river collector; - a theoretical study of the thermal and hydrodynamic characteristics of the river horizontal collector Slinky of the heat pump of the heating system of the house. Key words: nanofluids, Slinky collector, heat supply system, energy-independent house, efficiency of use, convective heat exchange. Reference: 1. Enhancing thermal conductivity of fluids with nanoparticles. Stephen U.S. Choi and J.A. Eastman. Energy Technology Division and Materials Science Division Argonne National Laboratory, Argonne, IL 60439. October 1995. 2. Shiyka I. O., Rymar T. I. Study of hydrodynamics and heat transfer of a dispersed nanofluid from ?-alumina in a river horizontal collector of a heat pump. All-Ukrainian competition of student scientific works in the field of "Energy": a collection of abstracts of reports.