scholarly journals The main indicators of choosing the scheme of providing hot water supply in cities

2019 ◽  
Vol 124 ◽  
pp. 05021
Author(s):  
F Gazizov ◽  
I. Ahmetova
Keyword(s):  
Boundary Conditions ◽  
Water Supply ◽  
Heat Supply ◽  
Hot Water ◽  
Independent Variables ◽  
Useful Life ◽  
Hot Water Supply ◽  
Heat Supply Systems ◽  
Supply Systems ◽  
Weight Coefficients

In the article the basic indicators defining the choice of this or that scheme of the organization of the closed hot water supply of the cities (further – HWS) using open schemes of HWS are considered. Block diagrams of boundary conditions and independent variables are presented. A pyramid of conditions affecting the level of capital and annual costs for the maintenance of heat supply systems for the useful life (25 years) of the equipment is proposed. The main provisions of the method and the program of choosing the most appropriate scheme of transition to the closed circuit of preparation of hot water with the calculation of weight coefficients are formulated.

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 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 Development of technique and program for analysis of options for transition to a closed hot-water supply scheme for heat supply systems

2019 ◽  
Vol 21 (3) ◽  
pp. 126-134
Author(s):  
F. N. Gazizov ◽  
I. G. Akhmetova
Keyword(s):  
Water Supply ◽  
Heating System ◽  
Supply System ◽  
Hot Water ◽  
Operating Costs ◽  
Independent Variables ◽  
Hot Water Supply ◽  
Hot Water Supply System ◽  
Supply Systems ◽  
Transition Scheme

The article describes the prerequisites for development of methodology for integrated assessment of options for transition to a closed hot-water supply scheme. For analysis of promising options for transition to a closed system of hot water supply, criteria have been proposed that influence the choice of possible solutions. Block diagrams of boundary conditions and independent variables were created. A pyramid of indicators which affect the operating costs of heating system over 25 years of its operation was formulated. A method and a program for selecting the optimal transition scheme to a closed hot-water supply system with calculation of weighting factors have been developed.

A New Technology to Prevent the Formation of Limescale in Hot Water Supply Systems

2020 ◽  
Vol 841 ◽  
pp. 36-40
Author(s):  
Mardan Jalilov ◽  
Ayten Jalilova ◽  
Gulnar Feyziyeva ◽  
Makhanim Azimova
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Hot Water ◽  
Water Supply Systems ◽  
Water Requirements ◽  
Quality Of Water ◽  
Hot Water Supply ◽  
Calcium And Magnesium ◽  
Supply Systems

Given that the quality of water supplied to hot water supply systems must meet drinking water requirements, it is also important that the water preparation process is of great importance. The quality of that water is also important in terms of preventing the formation of heat in hot water systems. It is known that the main cause of the formation of water is the presence of calcium and magnesium cations and bicarbonate and sulfate anions in water. The traditional methods for preventing the limescale include the combination of calcium and magnesium cations from the water and replacing them with cations that are not easy to resolve at high temperatures. The quality of water treated by these methods does not meet drinking water requirements. Taking these into account, the Cl-anionizationprocess of drinking water has been developed in high-tech anionite technology. According to this technology, the first water from the city water gridis processed through anionite and activated carbon filters, which are mechanically charged with high anionite. The treated water is then cleaned out of microbes and bacteria through the ultraviolet disinfection equipment and delivered to the operator according to the quality requirements for drinking water. In the chlorine-anionization process, most of the sulfate and bicarbonate anions in water change to chlorine anions and their solidity remains constant. Thus, the density of the limescale-forming anions in the water decreases sharply and it meets the quality indicators of drinking water. High-grade anionite in the filter (8÷12) is regenerated by NaCl solution. The filtration rate of the solution from the anionite is determined depending on the concentration of calcium cations contained in the salt given for regeneration. Regeneration mode is such that the CaCO3 combination does not crumble when the anionite layer is formed. It is known that the temperature of the heated water in the hot water supply system does not exceed (60÷70)°C. In this case, the decomposition of limescale at Hc<2 mg-eq/l (carbonate hardness) is not observed. As carbonate hardness increases to 4 mg/l, the thin layer in the system shows a collapse. The basic element of the proposed technological schemeCl-anionite filter was applied at ADA University in Baku and positive results were obtained. Early observed collapse of pipes has been prevented and the working regime of hot water heaters has improved. A high-performance anionite such as A200EMBCl, which is a major ingredient of the UK's Purelite, and then the Russian-made AB-17-8 high-anionite anions have been used on the device.

scholarly journals Heat-exchange units with porous inserts

2019 ◽  
Vol 140 ◽  
pp. 05006 ◽  
Author(s):  
Oleg Stepanov ◽  
Boris Aksenov ◽  
Natalia Rydalina ◽  
Elena Antonova
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Heat Supply ◽  
Analytical Data ◽  
Porous Metal ◽  
Hot Water ◽  
Porous Metals ◽  
Proposed Model ◽  
Heat Supply Systems ◽  
Supply Systems

Currently, porous metals are not used in heat supply systems. Usage of porous materials in heat exchangers increases the heat transfer intensity and makes the heat exchangers more compact. An experimental setup consisting of two circuits was developed in order to study the influence of porous metals on heat transfer intensity. In the first circuit the hot coolant is water, which flows through narrow tubes inside the porous metal. In the second circuit the cold coolant is freon. The purpose of the study is to obtain experimental confirmation of the hypothesis of an increase in the heat transfer intensity when using porous metals. To achieve this goal, experiments were carried out, which showed the increased heat transfer intensity. The standard methods for calculating heat exchangers cannot be applied in this case as the inner pores’ surface is unknown. A mathematical model was compiled allowing engineering calculations for the heat exchangers of this type. The hot water temperature inside the heat exchanger is determined analytically. The resulting equation allows us to determine the cooling degree of the first coolant, i.e. hot water. The obtained deviations between experimental and analytical data are within the acceptable limits, which indicates the reliability of the proposed model.

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 Reliable and safe heat supply of residential buildings using wastewater after heaters for hot water supply

2019 ◽  
Vol 12 (2) ◽  
pp. 120-125
Author(s):  
O. D. Samarin
Keyword(s):  
Water Supply ◽  
Heat Supply ◽  
Power Plants ◽  
Residential Buildings ◽  
Thermal Power ◽  
Break Point ◽  
Hot Water ◽  
Outdoor Temperature ◽  
Capital Costs ◽  
Hot Water Supply

A modified scheme of heat supply of residential buildings with dependent connection to external heating networks is considered, providing reliability of heat supply and the necessary comfort in the premises due to mixing in some of wastewater after hot water supply (DHW) heaters at an outdoor temperature exceeding the break point of the temperature graph. The main equations describing the dependence of the water temperature in the supply line on the outside air temperature are analyzed, and a review of possible ways of regulating the heat supply and preventing "overflows" near the beginning and the end of the heating period is carried out, taking into account the requirements of the current regulatory documents of the Russian Federation. Calculations are made to determine the required proportion in the mixture for water consumption after the heaters of hot water supply in the conditions of the application of the scheme of connection of buildings to the heating network. The analysis of obtained results is given, and conclusions are drawn concerning expediency of application of the considered scheme. It is established that, from the power point of view, mixing of wastewater after heaters of DHW in the calculated quantity will allow to provide reliability of heat supply of the main group of residential buildings and safety of activity of people at high temperatures of outside air. It is shown that, at the same time, that the higher the current outdoor temperature, the greater the share of wastewater in the mixture, with the above dependence close to linear, and its numerical coefficients associated only with the calculated outdoor temperature in the construction area for the cold season. It is noted that the introduction of the proposed scheme is possible with a minimum reconstruction of existing units and structures without significant capital costs, and also gives a system-wide effect in the form of increased electricity generation in thermal power plants on thermal consumption.

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