scholarly journals XVI Международная конференция "Термоэлектрики и их применения --- 2018" (ISCTA 2018), Санкт-Петербург, 8-12 октября 2018 г. Новое направление применения термоэлектрических преобразователей энергии

2019 ◽  
Vol 53 (7) ◽  
pp. 875
Author(s):  
З.М. Дашевский ◽  
П.П. Константинов ◽  
C.Я. Скипидаров
Keyword(s):  
Cold Water ◽  
Waste Heat ◽  
Electrical Energy ◽  
Hot Water ◽  
Considerable Proportion ◽  
Thermoelectric Efficiency ◽  
Heating Systems ◽  
Additional Water ◽  
P Type ◽  
Thermoelectric Converters

AbstractIn southern countries, including European states, solar collectors for additional water-heating systems are widely used. However, the disadvantage of such systems is that a considerable proportion of solar energy cannot be used with increasing water temperature and dissipates into the environment. It is proposed to use waste heat at a high temperature, which is supplied to a thermoelectric generator (TEG) operating on the basis of a temperature difference between the hot water in the solar collector and cold water supplied to a radiator on the other TEG side. This is a new application of thermoelectric converters, in which the converter can act not only as a source of electrical energy but also as a source of low-potential heat coming from the radiator. The total conversion efficiency in such devices can reach 90%. It is shown that the use of p -type legs in a TEG with the cleavage planes of the legs parallel to the heat-flux direction instead of the conventional parallel orientation results in an increase in the thermoelectric efficiency by 25% on average in the temperature range of 100–300°C.

scholarly journals Thermoelectric Properties of Carbon Nanotubes

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4561 ◽  
Author(s):  
Nguyen T. Hung ◽  
Ahmad R. T. Nugraha ◽  
Riichiro Saito
Keyword(s):  
Carbon Nanotubes ◽  
Figure Of Merit ◽  
Waste Heat ◽  
Quantum Confinement Effect ◽  
Electrical Energy ◽  
High Seebeck Coefficient ◽  
Te Material ◽  
P Type ◽  
State Device ◽  
Solid State Device

Thermoelectric (TE) material is a class of materials that can convert heat to electrical energy directly in a solid-state-device without any moving parts and that is environmentally friendly. The study and development of TE materials have grown quickly in the past decade. However, their development goes slowly by the lack of cheap TE materials with high Seebeck coefficient and good electrical conductivity. Carbon nanotubes (CNTs) are particularly attractive as TE materials because of at least three reasons: (1) CNTs possess various band gaps depending on their structure, (2) CNTs represent unique one-dimensional carbon materials which naturally satisfies the conditions of quantum confinement effect to enhance the TE efficiency and (3) CNTs provide us with a platform for developing lightweight and flexible TE devices due to their mechanical properties. The TE power factor is reported to reach 700–1000 W / m K 2 for both p-type and n-type CNTs when purified to contain only doped semiconducting CNT species. Therefore, CNTs are promising for a variety of TE applications in which the heat source is unlimited, such as waste heat or solar heat although their figure of merit Z T is still modest (0.05 at 300 K). In this paper, we review in detail from the basic concept of TE field to the fundamental TE properties of CNTs, as well as their applications. Furthermore, the strategies are discussed to improve the TE properties of CNTs. Finally, we give our perspectives on the tremendous potential of CNTs-based TE materials and composites.

Spray-on thermoelectric energy harvester

MRS Advances ◽  
2018 ◽  
Vol 4 (15) ◽  
pp. 851-855 ◽  
Author(s):  
Robert E. Peale ◽  
Seth Calhoun ◽  
Nagendra Dhakal ◽  
Isaiah O. Oladeji ◽  
Francisco J. González
Keyword(s):  
Thin Films ◽  
Power Generation ◽  
Energy Harvester ◽  
Waste Heat ◽  
Spray Deposition ◽  
Electrical Energy ◽  
Seebeck Coefficients ◽  
Thermoelectric Energy ◽  
P Type ◽  
Energy From Waste

AbstractThermoelectric (TE) thin films have promise for harvesting electrical energy from waste heat. We demonstrate TE materials and thermocouples deposited by aqueous spray deposition on glass. The n-type material was CdO doped with Mn and Sn. Two p-type materials were investigated, namely PbS with co-growth of CdS and doped with Na and Na2CoO4. Seebeck coefficients, resistivity, and power generation for thermocouples were characterized.

scholarly journals Regeneration of Electrical Energy from Waste Geothermal Fluid in Geothermal Power Plants

2019 ◽  
Vol 2 (3) ◽  
pp. 525-531
Author(s):  
Mahmut Hekim ◽  
Engin Cetin
Keyword(s):  
Power Plants ◽  
Thermoelectric Generator ◽  
Waste Heat ◽  
Electrical Energy ◽  
Heat Energy ◽  
Hot Water ◽  
Geothermal Resources ◽  
Geothermal Fluid ◽  
Geothermal Power ◽  
Electrical Energy Production

Geothermal power plants are the plants that provide the conversion of thermal energy in geothermal fluid to electrical energy as a result of the extraction of underground hot water resources to the earth by drilling. The total installed power of geothermal power plants in the field of geothermal resources in Turkey has reached 1,336 MW. The geothermal fluid, which is used for electric power generation in geothermal power plants, is re-injected into the underground wells after electrical energy production. For efficient generation of electrical energy in geothermal power plants, it is aimed to reuse the waste heat energy within the geothermal fluid before it is sent to the re-injection well. To achieve this aim, thermoelectric generator modules which convert waste heat energy to electrical energy can be used. In this study, a thermoelectric generator-based geothermal power plant simulator that converts geothermal fluid waste heat into electrical energy is installed and commissioned in the laboratory conditions.

Waste Heat Recovery From Generators in the Deployed Army

2014 ◽  
Author(s):  
Gunnar Tamm ◽  
J. Ledlie Klosky ◽  
Jacob Baxter ◽  
Luke Grant ◽  
Isaac Melnick ◽  
...  
Keyword(s):  
Waste Heat ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Electrical Energy ◽  
The United States ◽  
Hot Water ◽  
Efficient Production ◽  
Water Heater ◽  
Power Sources ◽  
Fuel Savings

Electrical power generation in austere settings, such as combat zones, places a heavy burden on the US Army; high costs in both dollars and lives lost require that every drop of fuel be used effectively and efficiently. In remote locations such as combat outposts (COPs) and small forward operating bases (FOBs) in Afghanistan, electrical power derived from the Army’s standard Advanced Medium Mobile Power Sources (AMMPS) generator is even used to heat water for showers and heat living spaces. This heating requires conversion of thermal energy to mechanical energy, which is then converted to electrical energy and back to heat. Thus, a significant fuel savings could be realized through the more efficient production of heat. A combined heat and power system is proposed; efficiency is increased by routing the generator exhaust through simple ducting to a standard gas hot water heater to produce hot water with waste heat. With funding from the U.S. Army Rapid Equipping Force, cadets and faculty at the United States Military Academy designed, built and tested a system for under $1,000 in parts which was readily coupled to a 5 kW AMMPS generator to produce hot shower water. Results indicate a possible fuel savings of 1500–2000 gallons per year, 20–35% increased fuel utility, and the ability to provide 10–20 five gallon showers during every 5 hours of operation of each 5 kW generator. At a fuel cost of $20–50 per gallon in the deployed environment, and considering the large inventory of deployed generators, the payback for the Army could be tremendous.

Hybrid Liquid Desiccant/Vapour Compression Air-Conditioning Systems: A Critical Review

2008 ◽  
Author(s):  
Roza I. Christodoulaki ◽  
Emmanuil D. Rogdakis ◽  
Irene P. Koronaki
Keyword(s):  
Air Conditioning ◽  
Waste Heat ◽  
Electrical Energy ◽  
Hot Water ◽  
Vapor Compression ◽  
Solar Thermal Energy ◽  
Liquid Desiccant ◽  
Design Variables ◽  
Air Conditioning Systems ◽  
Vapour Compression

Hybrid Liquid Desiccant Cooling / Vapour Compression Systems is an environmentally friendly technology used to condition the internal environment of buildings. In contrast to conventional vapor compression air conditioning systems, in which the electrical energy drives the cooling cycle, desiccant cooling is heat driven; therefore, hybrid LDC/VCS have the potential to utilise cleaner energy sources such as gas, hot water, waste heat or solar thermal energy. In hybrid LDC/VCS, the latent cooling load is handled by the desiccant dehumidifier, while the sensible is handled by a conventional VCS. Hybrid systems combining liquid desiccant cooling with Vapor Compression Systems, Vapor Absorption Systems and Solar Collectors use less electrical energy compared to conventional air-conditioning alone, while these savings rise as the latent load increases. Unlike other surveys on desiccant cooling, this review focuses on a detailed coverage of the hybrid LDC/VC systems. Commonly used liquid desiccants are compared towards their physical properties. Hybrid LDC/VCS employing various components and features are summarized, while different system configurations are schematically presented. Key factors for the hybrid system performance are the desiccant material, the design variables and the conduction of experiments prior to operation.

scholarly journals Systematic Renovation Design of Surface Water Source Heat Pump for a Hot Spring Center Based on Thermodynamic Analysis

2021 ◽  
Vol 39 (3) ◽  
pp. 1026-1036
Author(s):  
Yijun Liu
Keyword(s):  
Surface Water ◽  
Optimization Design ◽  
Cold Water ◽  
Waste Heat ◽  
Hot Spring ◽  
Water System ◽  
Operating Conditions ◽  
Hot Water ◽  
Total Energy Consumption ◽  
Spring System

Currently, the application and renovation of surface water heat source pump (WHSP) mainly attempt to optimize heat exchangers, water pumps, the overall system, and economic frictional head loss. The mathematical model is often established and solved with such optimization objectives as optimization parameters, control forms, costs, and feasibility of investment and construction. There are relatively few studies that optimize the operating conditions with the minimal total energy consumption of system operations, and, on this basis, pursue global optimization design of the WSHP system. Therefore, this paper aims to carry out a systematic renovation design of the surface WSHP in a hot spring center in the national forest park of northern Guilin, southwestern China’s Guangxi Zhuang Autonomous Region. The project mainly covers the design of hot spring system, air-conditioning system, and hot water system, as well as the exergy analysis of WSHP system. Among them, the design of hot spring system includes the regulation of raw water, cold water, and warmed water; the constant temperature control of hot spring pools; the waste heat utilization of warmed water from the pools. The scientific nature of the design was proved through experiments.

scholarly journals Design and Simulation of Fuzzy Logic Based Temperature Control for a Mixing Process in Therapeutic Pool

2018 ◽  
Vol 159 ◽  
pp. 02039 ◽  
Author(s):  
Munadi ◽  
Erwin F. Ramadhan ◽  
Mochammad Ariyanto ◽  
Norman Iskandar ◽  
M.A. Amirullah ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Cold Water ◽  
Body Burden ◽  
Electrical Energy ◽  
The Body ◽  
Hot Water ◽  
Warm Water ◽  
Mixing Process ◽  
Water Heater ◽  
Set Value

Stroke is one cause of the most deaths, in which one way of handling stroke can be done with hydrotherapy. Hydrotherapy is a therapy that is done in the therapeutic pool which is filled with warm water in temperature 31°-34° C. When in the warm water, body burden becomes lighter, so the stroke patients with impaired movement of the body can train the nerves and muscles in order to restore the function of these organs. However, the warm water that is used for the therapy is produced by the heater that requires much electrical energy. This research discussed how to use solar energy to produce hot water using Indirect Evacuated Tube Solar Water Heater systems and make the control system for controlling the mixing process between the hot and cold water by using the Fuzzy Logic Control of the Mamdani method. Therapeutic pool system will be modeled using Simulink. Modeling the mixing process is made on the basis of mass balance and energy balance equations. Then the system will be simulated with interrupted condition and gets set value changes in a particular time. The FLC is successfully reached and maintained steady to a set value. The results will be compared to the performance of the one with Proportional Integral Derivative controller.

Control of a Supercritical CO2 Electro-Thermal Energy Storage System

2013 ◽  
Author(s):  
S. A. Wright ◽  
A. Z’Graggen ◽  
J. Hemrle
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Waste Heat ◽  
Storage System ◽  
Electrical Energy ◽  
Hot Water ◽  
Working Fluid ◽  
Heat Rejection ◽  
Plant Uses

Transcritical CO2 power systems are being investigated for site independent electro-thermal energy storage (ETES). The storage plant uses electrical energy with a standard vapor-compression heat pump/refrigeration cycle to store thermal energy as hot water and ice over a period of approximately 8 hours during low power demand. The power cycle is then reversed and operated as a simple Rankine cycle to produce ∼100 MWe for about 4.5 hours during peak demand. During the power generation cycle the storage plant uses the heat stored in the hot water tanks, together with ice melting, plus ambient heat rejection for the heat sink. For 100 MWe class power plants, the round trip efficiency is estimated to be up to 60%. CO2 was selected as the working fluid because it improves the ability of the plant to operate with high reversibility. In addition, it is compact and can operate below the freezing point of water. This report describes the major control characteristics of the plant, together with methods, tools, and results of the model. Because the plant is nearly “closed”, it must operate only by consuming electrical energy during the charging cycle and by producing electrical energy plus some waste heat during the discharge cycle. All other heat transfer processes occurs solely within the storage plant itself and consists of either heating or cooling water and by making or melting ice. For the plant to operate continuously, both the water thermal storage and ice storage must be returned to their initial conditions after every 24 hour period. Otherwise, small changes in the thermal environment during waste heat rejection or performance variations of internal components will cause the storage system to drift from its designed operating temperature, pressure and energy storage capability, challenging its ability to operate. The control concept for the storage plant addresses both the operation of the plant during charging and discharging. It also addresses strategies for control during off-design situations or due to disturbances such as load following or changes in ambient heat rejection conditions. The process simulations described in the paper include models for the main physical components of the plant including the turbomachinery, the heat exchanger network, states of charge of the cold and hot storage, and CO2 inventory.

scholarly journals CHARACTERIZATION OF EQUILIBRIUM CONDITIONS OF ADSORBED SILICA–GEL/WATER BED ACCORDING TO DUBININ–ASTAKHOV AND FREUNDLICH

2005 ◽  
Vol 4 (1) ◽  
Author(s):  
M. R. A. Afonso ◽  
V. Silveira Jr.
Keyword(s):  
Silica Gel ◽  
Waste Heat ◽  
Electrical Energy ◽  
Hot Water ◽  
Heat Sources ◽  
Equilibrium Conditions ◽  
Freundlich Equation ◽  
Adsorbed Mass ◽  
Good Agreement

Systems of adsorption have been studied as an alternative for the cooling systems for saving electrical energy. The main advantage is the heat as the driving sources, for example, hot water or waste heat, widely used in the industries, and solar energy. The pair adsorbent/ adsorbate determines the behavior of these systems. Therefore, the knowledge of the equilibrium conditions between the adsorbent and the adsorbate is very important. The pair silica gel/water has the advantage of exploiting low-temperature heat sources. In this paper, the equilibrium conditions of the pair silica gel/water were investigated and the data were used to identify the coefficients of Dubinin-Astakhov equation and Freundlich equation. The experiments consisted of measuring temperature and pressure for different adsorbed mass of water in the adsorbent (silica gel). The amount of adsorbed mass (kg) per adsorbent mass (kg) used were: 0.007, 0.013, 0.024, 0.047, 0.092, 0.162 and 0.209. Both equations showed good agreement with experimental data, the coefficients of regression (R2) were 0.991 on the Dubinin-Astakhov equation and 0.993 for the Freundlich equation.

Investigating the Thermoelectric and Structural Properties of Bismuth Telluride Thin Films for Harvesting Energy from Waste Heat

2012 ◽  
Vol 185 ◽  
pp. 77-80 ◽  
Author(s):  
Marcus Chiang Mun Leong ◽  
Fabian Chiang Mun Chun ◽  
Jae Lee Kai Wei ◽  
Peng Qi Zhen ◽  
Ye Ko San ◽  
...  
Keyword(s):  
Thin Films ◽  
Bismuth Telluride ◽  
Waste Heat ◽  
Electrical Energy ◽  
Energy Harvest ◽  
Atmospheric Conditions ◽  
Thermoelectric Thin Films ◽  
P Type ◽  
Energy From Waste

Recently, thermoelectric thin films have been gaining attention as potential thermoelectric generators that can be used to power external devices. Such films can recover electrical energy from waste heat and are environmentally friendly. Micro fabrication of thin films is achieved by sputtering on silicon films. In this study, the sputtering of Bismuth Telluride (N-type, P-type) films was investigated. Research has verified the efficiency of Bismuth Telluride films, but little is known about how the sputtering process affects the film's quality. Thus, the focus of this study explores how sputtering parameters of discontinuous sputtering intervals, exposure to normal atmospheric conditions and in situ annealing affect the thickness, thermoelectric properties, and microstructure of films. This will bring about a better understanding of the relationship between the sputtering process and the properties of the produced film for both N and P type materials. Recommendations based on this study can contribute to the production of more efficient thin films suitable for energy harvest application.

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