scholarly journals ENERGY EFFICIENCY OF COMBINED HEAT SUPPLY SYSTEMS

2021 ◽  
Vol 2 (39) ◽  
pp. 92-97
Author(s):  
R. Klimov ◽  
A. Morozovskaya
Keyword(s):  
Water Supply ◽  
Heat Supply ◽  
Fossil Fuel ◽  
Heat Supply System ◽  
Heat Pumps ◽  
Supply System ◽  
Hot Water ◽  
Solar Collectors ◽  
Hot Water Supply ◽  
Supply Systems

The consumption of energy resources in the world states is constantly growing from year to year. The production of fossil fuels is also increasing, but for various reasons it cannot fully cover the required amount from consumers. One of the most important consumption sectors is heat loads from heating, ventilation and hot water supply of industrial and residential buildings. To cover the thermal loads of heating and hot water supply, the necessary heat carrier is water heated to a certain temperature. The most promising from the point of view of heating water for hot water supply are solar collectors. Hot water for heating needs to be reheated practically throughout the entire heating period. The introduction of heat pumps is promising. When using solar collectors, the heating agent can be reheated in heat pumps. The aim of the study is to develop such a combined heat supply system that uses more renewable energy and as a peak source a fossil fuel boiler (electric energy), as well as a method for calculating this system to determine the optimal composition of equipment and rational modes of its operation. The methodology for calculating heat supply systems combining solar collectors, heat pumps and fossil fuel boilers is presented. The problem of load distribution between the main elements of the combined heat supply system should take into account the probabilistic component. This is due to the fact that with a changing real mode of operation, different thermal load of the equipment can be optimal. This is primarily influenced by the variable heat inputs from solar collectors during the day. According to the above method, it is possible to determine the optimal parameters of the heat supply system for different operating modes, at which the minimum consumption of fossil fuel will be ensured.

scholarly journals Equations of temperature graphics of a heating point with a two-stage scheme of heat exchangers of hot water supply

2020 ◽  
Vol 208 ◽  
pp. 02001
Author(s):  
Tatyana Rafalskaya
Keyword(s):  
Water Supply ◽  
Air Temperature ◽  
Water Consumption ◽  
Heat Exchangers ◽  
Heat Supply ◽  
Heat Supply System ◽  
Supply System ◽  
Hot Water ◽  
Two Stage ◽  
Hot Water Supply

The temperature of the water returned to the heating network from consumers largely determines the energy efficiency of the heat supply system. It depends on a number of parameters: outside air temperature, hot water supply heaters connection scheme, daily water consumption in the hot water supply system. The calculation of this temperature is usually performed numerically, which makes it difficult to control the modes of the heat supply system. From a practical point of view, a simpler toolkit is needed. In this paper, equations are proposed that allow directly determining the change in the heat output of heat exchangers depending on the outside air temperature and the temperature of the network water returned to the heating network. These equations are obtained on the basis of systematic modeling of variable operating modes of the heat supply system, using the method previously proposed by the author. The operating characteristics of the heat station are taken into account by the coefficients of the equations, for the determination of which the calculation formulas were obtained. The equations used are valid for substations with a two-stage mixed scheme of hot water supply heaters in the mode of maximum water consumption.

Equations of Temperature Graphs of Operation Modes of a Heating Station with a Two-Step Scheme of Connection of Hot Water Supply Heaters

2020 ◽  
pp. 29-41
Author(s):  
Т. А. Рафальская
Keyword(s):  
Water Supply ◽  
Water Consumption ◽  
Heat Supply ◽  
Heat Supply System ◽  
Supply System ◽  
Water Supply System ◽  
Hot Water ◽  
Water Heaters ◽  
Hot Water Supply ◽  
Hot Water Supply System

Постановка задачи. Температура обратной воды, возвращаемой в тепловую сеть от потребителей, является важным показателем энергоэффективности системы теплоснабжения. Она зависит от температуры наружного воздуха, схемы присоединения подогревателей горячего водоснабжения, суточного водопотребления в системе горячего водоснабжения. Ее расчет производится на ЭВМ, в основном численными методами. Необходимо получить уравнения, позволяющие напрямую определять температуру сетевой воды после каждой ступени подогревателей и возвращаемой в тепловую сеть. Результаты. Методом моделирования переменных режимов работы системы теплоснабжения получены уравнения температурных графиков работы теплового пункта с двухступенчатой смешанной схемой присоединения подогревателей горячего водоснабжения. Определены зависимости для коэффициентов уравнений температурных графиков после каждой ступени подогревателей горячего водоснабжения. Выводы. Полученные уравнения справедливы для отопительно-бытового графика центрального регулирования, в том числе со срезкой, в режиме максимального водоразбора в системе горячего водоснабжения. Анализ эксплуатационных режимов системы теплоснабжения выявил закономерности, позволяющие прогнозировать температуру обратной сетевой воды в зависимости от наружной температуры и переменного водоразбора в системе горячего водоснабжения. Statement of the problem. The temperature of water returned into a network from the user is an important indicator of the energy efficiency of the heat supply system. It depends on the outdoor temperature, the connection scheme of the hot water heaters, the daily water consumption in the hot water supply system and its calculation is carried out on a computer, mainly by numerical methods. It is necessary to obtain equations that directly determine the temperature of the network water after each stage of the heaters and returned to the heat supply network. Results. By the method of modeling variable modes of operation of the heat supply system, the equations of the temperature schedules of the operation of the heating station with a two-stage scheme for connecting the hot water heaters are obtained. The dependences for the coefficients of the equations of the temperature graphs after each stage of the hot water heaters are determined. Conclusions. The obtained equations are valid for the heating schedule of central regulation, including with a cut, in the maximum water consumption mode in the hot water supply system. An analysis of the operating modes of the heat supply system revealed patterns that makes it possible to predict the temperature of the return network water depending on the outdoor temperature and variable water consumption in the hot water supply system.

scholarly journals Analysis of procedures for heating, ventilation and air conditioning for transfer to low-temperature heat supply

2019 ◽  
pp. 8-8
Author(s):  
Stanislav Chicherin
Keyword(s):  
Water Supply ◽  
Heat Supply ◽  
Heating System ◽  
Heat Energy ◽  
Hot Water ◽  
Heat Consumption ◽  
High Quality ◽  
Hot Water Supply ◽  
Supply Systems ◽  
Selection Of

Introduction. Renovation of housing stock supposes construction of new buildings, where the main utilities consuming heat energy will be heating and hot water supply (HWS) systems. Under such conditions the task of heat consumption reduction by transfer to low-temperature and use of the associated procedures is relevant. Materials and Methods. Research was performed on the basis of residential and administration buildings designed within the whole Russia, the facilities were selected based on the year of putting into operation and their purpose. The source of data concerning buildings became documents included into the scope of the design and detailed documentation: plans, drawings and explanatory notes. As meeting the demands of hot water supply makes the main contribution to daily nonuniformities of heat energy consumption, the attention was paid to equipment of hot water supply systems. For calculations, the commercial product of Microsoft Office Excel 2010 was used. Results. During selection of roof boiler house as a source of heat supply increase in consumption of equivalent fuel in relation to the variant of connection to heat power plant operating on solid fuel by 187,314 tons of fuel oil equivalent is possible. General refusal from power-and-heat generation complicates operation of large district heat supply systems. The design parameters of coolant in building heating system differ from project to project: from 95/70 °С, used everywhere till the beginning of the XXI century, up to 90/65 °С corresponding to existing practice of designing or 80/60 °С as at the facility in Sevastopol. Reduction of design temperatures by 5 % is insufficient to decrease general heat consumption of the building. Reduction of heat consumption is explained by selection of advanced materials for pipeline heat insulation. Use of automation diagrams for heat points on the basis of regulator ECL Comfort 310 contributes to improvement of hydraulic control for heating systems, however, concealed automation results in violation of high-quality mode for heat network control and decrease of coolant parameters on adjacent (often non-automated) consumers. Conclusions. Supplement of central high-quality control by local constant temperature/variable flow control at individual heat unit and installation of temperature controllers on heating radiators with mechanical thermostatic head have potential for reduction of the heat energy volume used ineffectively. Increase in level of controllability for heating system together with cheaper and responsive automation systems are basic conditions for increase in quality of heat supply in future.

scholarly journals INVESTIGATION OF VARIABLE MODES OF CENTRALIZED HEAT SUPPLY SYSTEMS OPERATION WITH QUALITATIVE AND QUANTITATIVE REGULATION

2019 ◽  
Vol 10 (2) ◽  
pp. 79-91
Author(s):  
T. A Rafalskaya ◽  
A. R Mansurov ◽  
A. R Mansurova
Keyword(s):  
Water Supply ◽  
Flow Rate ◽  
Heat Load ◽  
Heat Supply ◽  
Heat Supply System ◽  
Hot Water ◽  
Constant Flow Rate ◽  
Network Water ◽  
Qualitative And Quantitative ◽  
Hot Water Supply

The combined method of generating electric and heat energy at CHP plants has been and remains the most effective way of fuel saving both in housing and communal services and in industry. In Russia, historically, a qualitative method of regulation has been adopted, which consists in changing the temperature of the fluid depending on the change in the temperature of the outside air at a constant flow rate of the fluid. An analysis of the heat supply schemes of a number of Russian cities revealed that central quality regulation at heat sources has practically ceased everywhere. In modern methods of calculating the qualitative and quantitative regulation, the main load is heating, and the load of hot water is taken into account only by increasing the flow rate of network water and the variable modes of joint operation of heating and hot water systems are not calculated. Thus, at present, there are no methods for calculating the qualitative and quantitative regulation, allowing to fully taking into account the effect of the load of hot water on the operation of heating systems. Therefore, in modern conditions, the previously developed methods and technological methods of controlling the combined heat load are characterized by a decrease in efficiency, and, accordingly, the problem of their optimization arises. For different temperatures of outdoor air, the calculation of variable operating modes of the heat supply system was carried out, which showed that the existing schedules of qualitative and quantitative regulation cannot provide a comfortable temperature condition of the premises. Under the conditions of a connected supply of heat, simply adding up the flows of network water for heating and hot water supply fails to achieve optimal thermal conditions for the premises. Therefore, further improvement of the technology of the central qualitative and quantitative regulation of the heat load taking into account hot water supply is required.

scholarly journals Improving a heat supply system by increasing the efficiency of the heat pump unit

2022 ◽  
Vol 2150 (1) ◽  
pp. 012033
Author(s):  
P V Rotov ◽  
R A Gafurov
Keyword(s):  
Heat Pump ◽  
Heat Supply ◽  
Operating Time ◽  
Heat Supply System ◽  
Supply System ◽  
Hot Water ◽  
Water Supply Systems ◽  
Network Water ◽  
Heat Pump Unit ◽  
Supply Systems

Abstract The reliability and efficiency of the operation of district heating systems is largely determined by the efficiency of preparation of heating network water. In open heat supply systems, make-up water, among other things, compensates for the water intake in hot water supply systems. A number of technologies have been developed that increase the efficiency of an open heat supply system by reducing the water consumption in the supply pipeline of the heating network, increasing the operating time of the heat pump, and increasing the specific generation of electricity for heat consumption at the CHP plant due to additional cooling of the network water in the return pipe of the heating network.

Идентификациякоррозииоцинкованныхтрубвсистемеводоснабжения

2019 ◽  
pp. 39-44
Author(s):  
A. Andrianov ◽  
V. Chukhin
Keyword(s):  
Water Supply ◽  
Technical Condition ◽  
Supply System ◽  
Hot Water ◽  
Galvanized Steel ◽  
Water Supply Systems ◽  
Steel Pipes ◽  
Industrial Buildings ◽  
Hot Water Supply ◽  
Supply Systems

Приведены данные исследования и применения нового способа идентификации коррозии систем внутреннего водопровода, изготовленных из стальных оцинкованных труб. Способ может быть использован для периодического мониторинга технического состояния систем холодного и горячего водоснабжения жилых, общественных и производственных зданий. Способ основан на определении в составе осадка на тестовом образце продуктов коррозии, в частности цинка и меди, входящих в состав металла трубопроводов и оборудования. Техническим результатом предлагаемого решения является возможность его применения непосредственно с начала эксплуатации системы водоснабжения, а также сокращение времени для идентификации коррозии трубопроводов и оборудования в ходе продолжительной эксплуатации.The data on the research and application of a new method for identifying corrosion of house water plumbing made of galvanized steel pipes are presented. The method can be used for regular monitoring of the technical condition of cold and hot water supply systems made of galvanized steel pipes in residential, public and industrial buildings. The method is based on determining corrosion products of pipelines and equipment, zinc and copper in particular, on a test biscuit. The technical result of the proposed solution is the possibility of its application directly from the start of the operation of the water supply system as well as reducing the time to identify the occurrence of corrosion of pipelines and equipment during longterm operation.

scholarly journals Estimation of Solar Hot Water System Operation for a Residential Building

2021 ◽  
Vol 7 (1) ◽  
pp. 1-6
Author(s):  
Olena Savchenko ◽  
◽  
Zenon Savchenko
Keyword(s):  
Water Supply ◽  
Residential Building ◽  
Supply System ◽  
Water Supply System ◽  
Hot Water ◽  
Water Supply Systems ◽  
Solar Fraction ◽  
Hot Water Supply ◽  
Hot Water Supply System ◽  
Supply Systems

Solar hot water supply systems can provide a significant part of the thermal energy needed in the residential sector. The use of solar hot water supply systems can reduce the consumption of traditional energy sources and, consequently, reduce greenhouse gas emissions. The aim of this article is to assess the operation of the solar heating system operation to provide the needs of the hot water supply system of a residential building with thermal energy. The efficiency of a flat solar collector operating in a single-circuit thermosyphon system of solar heating of a residential building in Lviv has been established. The solar fraction of the hot water supply system of a residential building is determined depending on the volume of hot water consumed, in particular 50, 60, 70, 80, 90, 100 l/day. It is established that the lower the need for hot water, the greater the solar fraction of the solar hot water supply system. Thus, the average annual solar fraction of the solar hot water supply system with a daily consumption of 50 l/day is 0.77, and with a daily consumption of 100 l/day the solar fraction is 0.39. The average value of the solar fraction for the solar hot water supply systems of the studied house is 0.55.

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