Solar assisted thermoelectric cooling/heating system for vehicle cabin during parking: A numerical study

The use of a storage tank to regulate the loads of the mini-CHP plant improves the technical and economic indicators of its operation. However, the results of studies of the use of a storage tank in heating systems, in contrast to hot water supply systems, are poorly represented. The purpose of the study is to determine the conditions and indicators under which the use of a storage tank to regulate the heating load of a mini-CHPP is economically viable. The study of the heat grid is based on solving the standard heat balance and heat transfer equations. Modeling of heat transfer in the heat recovery circuit of a cogeneration unit is carried out by approximating the passport specification of the equipment in the range of operating loads from 50 to 100 %. Modeling the standing time of the outside air temperatures is carried out in accordance with the method of B. Shifrinson and V.Ya. Khasilev. The conditions of the numerical study are quite typical for the heating network of Donetsk. For the first time, to satisfy the conditions of a numerical study, the dependence of the available and used thermal capacity of the storage tank on the outside air temperature has been established for different values of the design volume of the tank. The quantitative characteristics of the influence of the design volume of the storage tank on electricity generation during peak, half-peak and minimum power system loads are investigated. The reliability of the results obtained is determined by the correct use of proven methods for calculating the operation parameters of water heating system and heat devices. The study shows that the use of a storage tank to regulate the heating load of a mini-CHPP is technically and economically feasible. With the design volume of the storage tank in the range of 65–126 m3 per 1 MW of the connected heating load, the simple payback period of the mini-CHPP varies insignificantly and can be considered acceptable. The presence of a storage tank allows realizing the maneuverable capabilities of cogeneration units, while maintaining a high share of energy generation in combined mode. The district heating coefficient, equal to one, allows achieving high efficiency of fuel utilization for generation of both electrical and thermal energy. The research results can be used in municipal heat supply systems when introducing gas piston cogeneration units.

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Numerical study of a Solar Absorption Refrigeration Machine

E3S Web of Conferences ◽

10.1051/e3sconf/202015001009 ◽

2020 ◽

Vol 150 ◽

pp. 01009

Author(s):

J. Dardouch ◽

M. Charia ◽

A. Bernatchou

Keyword(s):

Distillation Column ◽

Operating Temperature ◽

Numerical Study ◽

Heating System ◽

Coefficient Of Performance ◽

List Type ◽

Absorption Refrigeration ◽

Solar Collectors ◽

Solar Absorption ◽

Refrigeration Machine

In this paper, we present a numerical study of a single-stage absorption refrigeration machine, operating with a couple of water-ammonia fluids, equipped with a distillation column and associated with a solar heating system using solar collectors. The study has showed the benefit of using the distillation column which is manifested by: The decrease of the operating temperature, The improvement of the coefficient of performance, Surface reduction of the solar collectors, The improvement of the solar coefficient of performance. The solar study shows that the absorption refrigeration machine equipped with a distillation column is better suited to solar energy with significantly better performance compared to the simple absorption refrigeration machine.

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Numerical investigation of the energy flexibility of different heating and cooling systems

E3S Web of Conferences ◽

10.1051/e3sconf/201911106001 ◽

2019 ◽

Vol 111 ◽

pp. 06001 ◽

Cited By ~ 1

Author(s):

Evangelia Loukou ◽

Mingzhe Liu ◽

Hicham Johra ◽

Per Heiselberg ◽

Bianca A. Dia ◽

...

Keyword(s):

Energy Use ◽

Numerical Study ◽

Renewable Energy Sources ◽

Heating System ◽

Economic Benefits ◽

Comfort Level ◽

Grid System ◽

Cooling Systems ◽

Load Shifting ◽

Heating And Cooling

The significant expansion of intermittent renewable energy sources can compromise the stability of energy grids due to the mismatch between instantaneous energy use and production. Buildings have a large potential for energy storage and demand-side management, which can offer energy flexibility to a Smart Grid system. Smart control of heating, ventilation and air conditioning systems is a great solution for improving flexible energy use, load shifting and power peak shaving. This numerical study compares the energy flexibility potential of three different heating and cooling systems implemented in a nearly zero-energy office building. The energy flexibility strategy consists in the modulation of heating / cooling indoor temperature set points according to an energy price signal. The energy flexibility assessment was performed based on the energy shifting ability, indoor thermal comfort level and economic benefits. This article establishes a better understanding of the flexibility potential of common and innovative heating / cooling technologies. Lindab Solus system has the highest load shifting ability with a flexibility index of 67.41%, followed by the radiator heating system, scoring a 59.92%, and the underfloor heating system with 56.65%. It is clear that the selection between different heating/ cooling systems can have a great impact on the energy flexibility of the grid system.

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The Possibility of Using the Ground as a Seasonal Heat Storage: The Numerical Study

Volume 2, Parts A and B ◽

10.1115/ht-fed2004-56185 ◽

2004 ◽

Cited By ~ 2

Author(s):

Pawel Olszewski

Keyword(s):

Solar Energy ◽

Heat Storage ◽

Numerical Study ◽

Storage System ◽

Heating System ◽

Numerical Code ◽

Space Heating ◽

Solar Collectors ◽

Seasonal Heat ◽

The One

Humankind can effectively utilize only part of the solar energy reaching a surface of the Earth. It is due to the low density of the solar radiation and its unfavorable distribution. The majority of solar energy falls to the low latitude countries, where space-heating requirements are marginal. In these countries the solar heat is used for preparing water for washing or cleaning purposes, and this process works in one, or — maximum — a few daily cycles. In countries located at higher latitudes, where space heating is necessary in cold months, the current solar energy is insufficient to meet the space heating demand. The heat storage in deep layer of the ground is the one of possible way for solution of this problem. During the heating season, energy storage is discharged supplying the heat pomp cooperating with domestic heating system and during the summer months the storage can be charged by fluid heated in solar collectors. The main aim of presented research was analysis of using the ground layer as a heat storage system in the countries located in higher latitudes. The first variable taken into consideration was the output temperature of water leaving the solar collectors. The temperature distribution in the ground depends on the inlet water temperature, primary heated in the solar collectors, and forced into vertical boreholes. The temperature field in the ground was calculated using the duFort-Frankel finite-difference numerical method. A numerical code for 3D time dependent storage simulation has been created. The next step of analysis was calculation of waters’ temperature at the borehole output during cold months when the ground storage is discharged. This water works as a low-temperature reservoir of the heat pomp supplying the dwelling heating system. The solution of the problem is focused on an optimization of all parameters for the most efficient utilization of energy stored in the ground. The numerical genetic algorithms are scheduled to use to achieve this target.

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Numerical Study of Lightning Protection of Wind Turbine Blade with De-Icing Electrical Heating System

Energies ◽

10.3390/en13030691 ◽

2020 ◽

Vol 13 (3) ◽

pp. 691

Author(s):

Yang Zhao ◽

Xi Wang ◽

Qibin Zhou ◽

Zhenxing Wang ◽

Xiaoyan Bian

Keyword(s):

Wind Turbine ◽

Turbine Blade ◽

Numerical Study ◽

Heating System ◽

Wind Turbine Blade ◽

Electrical Heating ◽

Electromagnetic Transients ◽

Lightning Protection ◽

Lightning Strikes ◽

Lightning Current

In order to solve the problem of icing on the surface of wind turbine blade, a heating system that includes a carbon fiber net (CFN) and power cables is proposed recently. When lightning strikes at the blade with a de-icing heating system, the blade and its heating system are more easily damaged due to the overvoltage between the lightning protection system (LPS) of the blade and the heating system. In this paper, the models of a wind turbine blade with the de-icing heating system are established by Alternative Transients Program/Electromagnetic Transients Program (ATP–EMTP) and the accuracy of models is verified through an experiment. With these models, the influence of lightning current, surge protective devices (SPDs) and earthing resistance of wind turbine are analyzed by calculating the voltage between the down-conductor of the LPS and the heating system. The results show that the voltage is positively correlated with lightning current amplitude and negatively correlated with the front time of lightning current. SPDs are quite useful to reduce the voltage, and an optimal installation scheme of SPDs is obtained by simulation. It is noted that voltage decreases slightly with the increasing earthing resistance with the optimal installation scheme of SPDs.

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