scholarly journals MATHEMATICAL MODEL OF HEAT SUPPLY INSTALLATION AS AN OBJECT OF ECONOMIC EFFICIENCY AND AUTOMATION

2020 ◽  
Vol 2 (2) ◽  
pp. 69-74
Author(s):  
S. HORIASHCHENKO ◽  
◽  
Yu. KRAVCHIK ◽  
O. PIDGORNYI ◽  
◽  
...  

Solar energy is widely used in cases where the inaccessibility of other energy sources in combination with a sufficient amount of solar radiation justifies it economically. With the help of a system of solar collectors, you can significantly reduce energy costs for hot water supply and heating. In addition, the use of this system helps reduce CO2 emissions. The potential of solar energy in Ukraine is quite high. According to the climatic conditions of our region, solar activity is slightly lower than in the southern regions, so the use of flat solar collectors, which use both direct and scattered solar radiation, is effective for our region. The use of heat collectors in the home for water supply and heating of small areas is economically feasible, as it does not require significant costs. Heat supply plants using non-traditional energy sources are promising in terms of fuel savings and reduction of harmful effects on the environment. To increase the service life, economical use of heat and fuel, efficient operation of the installation requires the use of automation. The article considers the development of a mathematical model of a heat supply installation based on a solar collector. For automated control of the heat supply installation, it is necessary to know the properties of this installation as a whole and its individual elements. For this purpose, models of individual elements of the heat supply installation in a linear approximation are considered. The solar collector is conditionally divided into two parts. The model of the ground heat exchanger is developed. Also e battery models and consumer premises. The given matrices of elements of installation of heat supply are united in the uniform system of matrices. The obtained results allow estimating in advance efficiency of their use and economic attractiveness.

2014 ◽  
Vol 889-890 ◽  
pp. 1333-1336
Author(s):  
Yu Fu ◽  
Kai Chen ◽  
Fei Ying Fu ◽  
Xin Bin Wang

Solar thermal collector converts solar radiation energy into useful thermal energy and transfers to a transport fluid flowing through the system. The collected energy can be used either direct to space or water heating equipment, or to a thermal storage for later use. Along with fast development, not only domestic hot water supply is needed, but also space heating and cooling are required. Also, limited roof space is another key barrier that should be considered. Furthermore, most of the building integration with solar collectors are mounted on the roof top by flat or tilt angle at present. It is considered to be a failure of low level architectural quality because the collector is used only for application and seems as an independent technical element of the building. With the consideration of the above, novel type of solar collector has been proposed to realize the utilization and offset the barriers. This novel solar collectors is especially suitable to supply domestic hot water, and combines with ASHP for multi-function, space heating and cooling as well as domestic hot water supply. Additionally, it is well integrated with high-rise residential buildings, which is good for aesthetic.


2012 ◽  
Vol 16 (suppl. 2) ◽  
pp. 471-482 ◽  
Author(s):  
Velimir Stefanovic ◽  
Sasa Pavlovic ◽  
Marko Ilic ◽  
Nenad Apostolovic ◽  
Dragan Kustrimovic

Solar energy may be practically utilized directly through transformation into heat, electrical or chemical energy. A physical and mathematical model is presented, as well as a numerical procedure for predicting thermal performances of the P2CC solar concentrator. The demonstrated prototype has the reception angle of 110? at concentration ratio CR = 1.38, with the significant reception of diffuse radiation. The solar collector P2CC is designed for the area of middle temperature conversion of solar radiation into heat. The working fluid is water with laminar flow through a copper pipe surrounded by an evacuated glass layer. Based on the physical model, a mathematical model is introduced, which consists of energy balance equations for four collector components. In this paper, water temperatures in flow directions are numerically predicted, as well as temperatures of relevant P2CC collector components for various values of input temperatures and mass flow rates of the working fluid, and also for various values of direct sunlight radiation and for different collector lengths. The device which is used to transform solar energy to heat is referred to as solar collector. This paper gives numerical estimated changes of temperature in the direction of fluid flow for different flow rates, different solar radiation intensity and different inlet fluid temperatures. The increase in fluid flow reduces output temperature, while the increase in solar radiation intensity and inlet water temperature increases output temperature of water. Furthermore, the dependence on fluid output temperature is determined, along with the current efficiency by the number of nodes in the numerical calculation.


2021 ◽  
Vol 295 ◽  
pp. 04005
Author(s):  
Sergey Batukhtin ◽  
Andrey Batukhtin ◽  
Marina Baranovskaya

According to experts’ forecasts, by 2040 the global demand for energy will increase by 37%, and renewable energy sources in the next 20 years will become the fastest growing segment of the world energy, their share in the next decade will grow by about one and a half times. Solar energy is the fastest growing industry among all non-conventional energy sources and is gaining the highest rates of development in comparison with other renewable energy sources. In this article, the authors provide an overview of the technologies that increase the efficiency and productivity of solar panels, only the investigated methods are described that can speed up the process of introducing solar energy instead of traditional. All the methods described can increase the efficiency of systems that are based on the use of the sun as the main source of energy. The authors presented and described the scheme of a solar-air thermal power plant, which will improve energy efficiency through the use of a regenerative air solar collector with increased heat transfer efficiency. Strengthening will be achieved through the use of hemispherical depressions on the surface that receives solar radiation. A schematic diagram is given and the principle of operation of such a solar collector is described in detail. A comparative calculation of the intensification of the solar collector with the use of depressions and without the use as modernization was carried out, on the basis of which a conclusion was made about the efficiency of using this type of solar collector and the economic effect from the application of this method. A description of the method for calculating the solar collector is given, thanks to which this development can be used and implemented in existing heating and hot water supply systems.


Solar Energy ◽  
2004 ◽  
Author(s):  
Oleg P. Kovalev ◽  
Alexandr V. Volkov

During long-term time, the laboratory of non-traditional energetic is been busy with development and introduction of solar water heating systems for hot water supply. The systems with solar collectors of 40 m2 area have been developed and introducted. For estimation of their efficiency we should know flux density of solar radiation, proceeding to surface at the given place. However in Primorye Region at actinometrical watching only four meteostations in the Southern part are carrying out straight measurements of solar radiation flux, and the others record data which concern only solar radiation regime (the amount of solar radiation hours, relation of watching duration of solar radiation to possible duration, the amount of days without sun, etc.). We suggested the expression, which according to know data of solar radiation and cloudiness, recorded practically on all meteorological stations gives possibility to calculate for Primorye Region month sums of total radiation proceeding to horizontal surface. The comparison of estimated values with measured ones gives the error to 3...9% with regard to average many years values, and are in the range of variability of measured values for separate years. In Primorye Region more than 250 m2 of solar collectors were installed; and among them 150 m2 were developed with the laboratory, to position on 2003.11.01.   NOTE: This paper was presented at the 2004 International Solar Energy Conference and was inadvertently omitted from the 2004 ASME proceedings. The page range refers to the 2005 International Solar Energy Conference Print Proceedings, where it was subsequently published.


Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1272 ◽  
Author(s):  
Dorota Anna Krawczyk ◽  
Mirosław Żukowski ◽  
Antonio Rodero ◽  
Ruta Bilinskiene

A solar collector market is most European countries is at the stage of continuous development, however its expansion rate differs. It shows that much more factors than only the local solar radiation is important, including a technology progress, costs, local manufactures’ engagement, an economic government support or an environmentally consciousness raising relevant to a mitigating climate change. We conducted the analysis for a public office building, with a few toilets and a social room, used by 54 people. As a primary heat source for HVAC and DHW systems an oil boiler was used, whereas solar collectors were considered as an energy source for hot water preparation. The analysis was conducted for three locations of the building: Bialystok (Poland), Cordoba (Spain) and Kaunas (Lithuania), using a simulation software delivered within the framework of VIPSKILLS project. Theoretical hot water consumption was considered as 3–7 dm3/(day person) in compliance with national recommendations. It was found that beam solar radiation share in a total radiation balance was nearly twice higher in Cordoba than in Bialystok or Kaunas. The highest efficiency (44%) was estimated in Cordoba for solar collectors installed with the tilt angle between 45–50°. In case of Bialystok and Kaunas the efficiency was lower than in Cordoba and nearly equal 40–41% and the recommended tilt angle was in a range 30– 45°.


Author(s):  
Наталья Михайловна Попова ◽  
Дмитрий Михайлович Чудинов ◽  
Ольга Анатольевна Сотникова ◽  
Наталья Александровна Петрикеева

Вопрос энергообеспечения зданий и сооружений на территориях с малоразвитой инженерной инфраструктурой и децентрализованными системами частично может быть решен применением солнечных систем теплоснабжения (или горячего водоснабжения). Подобные системы - надежные, безопасные, простые и малозатратные в эксплуатации, сокращают потребление традиционных энергоресурсов и эмиссию вредных выбросов в атмосферу. Возможность массового внедрения гелиоустановок в основном сдерживается стоимостными показателями, определяющими срок окупаемости. Ежегодный рост цен на традиционное органическое топливо, возможность изготовления солнечных коллекторов собственными силами и средствами может повысить их привлекательность. В работе произведена оценка рентабельности солнечной системы горячего водоснабжения гостиницы, расположенной в селе Бабяково Воронежской области для двух временных периодов (2005 г. и 2021 г.) с учетом повышения стоимости на электроэнергию, являющуюся основным традиционным энергоресурсом. Солнечные коллекторы гелиосистемы производятся собственными силами и средствами. Внедрение гелиоустановки для нужд горячего водоснабжения в традиционную систему теплоснабжения гостиницы позволит сократить потребление электроэнергии на 44 %. В работе показано, что повышение цены на электроэнергию за период с 2005 г. по 2021 г. не компенсировало рост стоимости материалов на изготовление солнечных коллекторов. При этом срок окупаемости для 2005 г. составлял 6,0 лет, для 2021 г. - равен 13,1 годам. Эффективная эксплуатация соответствует периоду 6,9 лет. Установка относительно российских и зарубежных производителей по затратам занимает среднее положение. При стоимости электроэнергии на уровне европейского рынка (2021 г.) срок окупаемости составляет 1,4 года. The issue of energy supply of buildings and structures in areas with poorly developed engineering infrastructure and decentralized systems can be partially solved by the use of solar heat supply systems (or hot water supply). Such systems (reliable, safe, simple and low-cost in operation) reduce the consumption of traditional energy resources and the emission of harmful emissions into the atmosphere. The possibility of mass implementation of solar plants was largely constrained by cost indicators that determined the payback period. The annual rise in prices for traditional organic fuels, the ability to manufacture solar collectors with their own strength and means can increase their attractiveness. The work assessed the profitability of the solar hot water supply system of a hotel, located in the village of Babyakovo, Voronezh Region, for two time periods (2005 and 2021), taking into account the increase in the cost of electricity, which is the main traditional energy source. The solar collectors were produced in-house. The introduction of a solar plant for the needs of hot water supply in the traditional heating system of the hotel can reduce electric energy consumption by 44 %. The paper shows that the increase in the price of electricity for the period from 2005 to 2021 did not compensate for the increase in the cost of materials for the manufacture of solar collectors. At the same time, the payback period for 2005 was 6,0 years, for 2021 was equal to 13,1 years. Efficient operation of the plants covers a period of 6,9 years. The installation of Russian and foreign manufacturers in terms of costs occupies an average position. With the cost of electricity at the level of the European market (2021) the payback period is 1,4 years.


Author(s):  
Vitaliy A. Butuzov ◽  
Vitaly V. Butuzov ◽  
Elena Bryantceva ◽  
Ilya Gnatyuk

Approaches to the organization of solar heat supply in Russia have a number of differences in comparison with the global experience, in particular, in the field of processing solar radiation data, designing solar collector designs, design techniques, construction and testing of solar heating systems, and the practice of creating and using solar plants. Examples of implementation of projects for creating heat supply systems in different regions of Russia are presented, from the southern (Krasnodar Territory) to the northern (Yakutia). A methodology for converting data for direct and diffuse solar radiation of NASA by taking into account the results of measurements of weather stations, which provides the possibility of their practical use, is presented. Data on the number, types, annual volumes of supplies, and names of producers of solar collectors in Russia are presented. Methodical approaches to the development of solar collectors structures based on the results of comparing the energy consumption for their production with the amount of energy produced by them during their lifetime are considered. A comparative analysis of solar design methodology in Russia and in Europe has been performed. Prospects for the construction of solar heat installations in Russia up to 2030 are considered.


2018 ◽  
Vol 82 (1) ◽  
Author(s):  
Юрий Анатольевич Селихов ◽  
Виктор Алексеевич Коцаренко

Европейские страны демонстрируют высокие возможности простого преоб­разования солнечной энергии в тепловую энергию, которая может успешно использо­ваться для обеспечения различного рода технологических, отопительных и бытовых потребностей. Кроме того, ввод в эксплуатацию сол­нечных установок улучшает экологическую ситуацию района потребления тепловой энер­гии за счет снижения объемов выбросов загряз­няющих веществ, к которым относятся продукты сгорания органического топлива, используемого для производства тепловой энергии. В настоящее время в южных районах Украины уже используются солнечные установки для горячего водоснабжения и отопления. Однако, внедрение новых энергетических и экономически выгодных установок идет медленными темпами, что объясняется довольно высокими стоимостными показате­лями, как отечественных, так и зарубежных установок. Таким образом, на наш взгляд, является актуальной концепция создания новых солнечных установок, наиболее привлекательных для потенциаль­ного потребителя. Реализация данной кон­цепции возможна при таком варианте исполнения солнечных установок, когда затраты на выработку тепловой энергии с помощью этих установок будут ниже уровня суммарных затрат на получение тепловой энергии традиционными способами (в частности, в котельных установках). Однов­ременно с этим, срок окупаемости солнечных установок должен быть соизмерим с гарантийным сроком их эксплуатации. Для выполнения поставленных условий представ­ляется целесообразным разработка таких конструкций солнечных коллекторов, которые позволяли бы минимизировать затраты на их изготовление, монтаж и обслуживание. Это может достигаться за счет использования дешёвых отечественных материалов, выпуск которых гарантирован в достаточных объемах на протяжении длительного срока. Разработка, изготовление и внедрение двухконтурных солнечных установок позволило круглогодично эксплуатировать солнечный коллектор, но капитальные и эксплуатационные затраты при этом были  на таком уровне, что для полной окупаемости солнечной установки могло понадобиться более пяти лет, так как солнечные коллектора изготавливались из металла.  В рамках сформулированной задачи нами был разработан и изготовлен солнечный коллектор из полиэтиленовой пленки. Предлагается двухконтурная солнечная установка для горячего водоснабжения и отопления, у которой солнечные коллектора изготовлены из полиэтиленовой пленки. Такая установка разработана, изготовлена и запущена в эксплуатацию в одном южном регионе Украины. На установке были получены экспериментальные результаты работы установки в разных режимах в течение года. После обработки этих данных были получены обобщающие зависимости: плотности теплового потока от температуры теплоносителя в коллекторе, времени работы установки в течение светового дня и расхода теплоносителя; коэффициента полезного действия от плотности теплового потока; максимального коэффициента полезного действия от максимальной плотности теплового потока; количества теплоты при конвекции от скорости натекания ветрового потока от 1 до 6 м/с на внешнюю поверхность солнечного коллектора. Зависимости получены при разных объемных расходах V от 0,5 до 3,0 м3/ч теплоносителя. Максимальная погрешность проведенных расчетов не превышает 5 %.  European countries demonstrate high opportunities for simple conversion of solar energy into thermal energy, which can be successfully used to provide various types of technological, heating and domestic needs. In addition, the commissioning of salt plants improves the ecological situation in the area of consumption of thermal energy by reducing emissions of polluting substances, which include combustion products of organic fuel used for the production of thermal energy.  At present, solar installations for hot water supply and heating are already used in the southern regions of Ukraine. However, the introduction of new energy and economically advantageous plants is proceeding slowly, which is explained by rather high cost indices, both domestic and foreign installations.Thus, in our opinion, the concept of creating new solar installations that are most attractive to a potential consumer is relevant. Implementation of this concept is possible with such an option of solar installations, when the cost of generating thermal energy using these facilities will be lower than the total cost of obtaining thermal energy by traditional methods (in particular, in boiler plants). However, with this, the payback period of solar installations should be commensurate with the warranty period of their operation. To fulfill the set conditions it is advisable to develop such designs of solar collectors that would allow to minimize the costs of their manufacture, installation and maintenance. This can be achieved through the use of cheap domestic materials, the release of which is guaranteed in sufficient quantities over a long period. The development, production and implementation of dual-circuit solar installations allowed the solar collector to be operated year-round, but the capital and operating costs were at such a level that it would take more than five years to fully pay for the solar installation, since the solar collectors were made of metal. Within the framework of the formulated task, we developed and manufactured a solar collector made of polyethylene film. A double-circuit solar installation is proposed for hot water supply and heating, in which the solar collectors are made of polyethylene film. Such an installation is designed, manufactured and commissioned in one southern region of Ukraine. Experimental results of the installation in different modes during the year were obtained at the plant. After processing of these data, generalizing dependencies were obtained: the heat flux density from the coolant temperature in the collector, the operating time of the installation during the daylight and the flow of the coolant; coefficient of efficiency from the density of heat flow; the maximum efficiency from the maximum heat flux density; the amount of heat in convection from the rate of leakage of the wind flow from 1 to 6 m / s on the outer surface of the solar collector. Dependencies were obtained at different volumetric flows V from 0.5 to 3.0 m3 / h of the heat carrier. The maximum error in the calculations does not exceed 5%.


Author(s):  
Shigeki Hirasawa ◽  
Tsuyoshi Kawanami

We studied effects of parameters on collector efficiency of evacuated solar collector system to get hot water near 100°C. Change of temperature in the solar collector system is calculated for a daily change of solar radiation with 5 minutes cloud. Six operation-control methods are examined. Calculation results show that the effect of the control methods on average collector efficiency for one day is small as 1%. Best control method to minimize effect of the cloud on exit temperature fluctuation of the water is that the flow rate of the water is controlled proportional to the solar radiation. Two types of heat storage system are examined: a non-circulating type (supply new water and accumulate heated water in the heat storage tank) and a circulating type (circulating water from the heat storage tank). The non-circulating type is effective to use the solar energy in the daytime, and the circulating type is effective to use solar energy in the evening. Also, we measured temperature of a collector plate under actual solar radiation in a fine day.


2020 ◽  
Vol 7 (1) ◽  
pp. G9-G14
Author(s):  
S. Shkrylova ◽  
V. Kostenko ◽  
I. Skrynetska

In the conditions of the global ecological crisis in the world and Ukraine, the issue of finding alternative energy sources becomes relevant. One of the most common types of renewable energy is solar energy. In Ukraine today, the most promising direction of using solar energy is its direct transformation into low-potential thermal energy. To get electric power, solar radiation is the mere alternative to electric power generated from mined fuel, and without the pollution of air and water, or adverse consequences manifested in global warming. The disadvantage of this type of installation is the limitation of the duration of light time, as well as the effect of cloudiness. During the day, the number of solar radiation changes, to stabilize it is necessary to accumulate and accumulate it for further use, the technical implementation of stable operation of solar installation due to the use of terrestrial radiation and the accumulator of a specific part of solar energy is proposed. The purpose of the work is experimental studies to ensure the stable operation of the solar collector under cloudy conditions. The paper is aimed at the stabilization of the operation of the solar installation and to obtain additional heat after the Sun’s cloud cover. The use of a solar thermal collector is advisable in solar heating and hot water systems in conditions of alternating solar radiation. The results of physical modeling have proved the efficiency of the method of combining types of thermal radiation, due to the accumulation of energy it is possible to increase the quantitative index of solar energy in the conditions of cloudiness by 3 times Keywords: alternative energy, solar energy, solar collector, thermal energy, clouds, terrestrial radiation, ecology.


Sign in / Sign up

Export Citation Format

Share Document