scholarly journals Research of functionality of using a storage tank for regulating heating load of a gas piston mini-CHPP

Vestnik IGEU ◽  
2021 ◽  
pp. 21-30
Author(s):  
N.V. Kolesnichenko ◽  
S.M. Safiants ◽  
A.B. Biryukov ◽  
O.V. Litvinov
Keyword(s):  
Heat Transfer ◽  
Storage Tank ◽  
High Efficiency ◽  
Numerical Study ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Water Supply Systems ◽  
Heating Load ◽  
Supply Systems

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.

scholarly journals EFFICIENCY OF THERMAL ENERGY GENERATION BY COGENERATION PLANTS DUE TO THE MAXIMUM USE OF HEAT

2021 ◽  
Vol 7 (2(38)) ◽  
pp. 66-71
Author(s):  
Maxim Olegovich Maximov
Keyword(s):  
Water Supply ◽  
Thermal Energy ◽  
District Heating ◽  
Heating System ◽  
Heat Losses ◽  
Hot Water ◽  
Water Supply Systems ◽  
Hot Water Supply ◽  
Hot Water Supply System ◽  
Supply Systems

ignificant heat losses in centralized heating and hot water supply systems during the transportation of heat carriers lead to the need for decentralization of heat generating installations. It is shown that steam and gas installations for combined heat and power generation deserve the greatest attention. The ways of increasing the efficiency of cogeneration plants of various capacities based on CCGT by utilizing the heat of the heating system by installing recuperative heat exchangers on the return lines of the heating system after heating devices that are connected to the hot water supply network are substantiated, which makes it possible to reduce heat losses to the environment. The proposed system of rational interaction of the power plant with the heating and hot water supply system, which allows increasing the thermal efficiency of the cogeneration plant by 2%, which corresponds to a fuel saving of 3% due to the more complete use of the thermal energy of steam, which is sent as a selection for district heating. This article discusses solutions aimed at increasing the efficiency of heat generation by cogeneration plants by maximizing the use of heat from the exhaust steam of turbines.

scholarly journals District heating system simulation considering consumer and pump operation features

Vestnik MGSU ◽  
2019 ◽  
pp. 748-755 ◽  
Author(s):  
Saule K. Abildinova ◽  
Stanislav V. Chicherin
Keyword(s):  
Mathematical Model ◽  
Energy Consumption ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Water Supply Systems ◽  
Problem Solution ◽  
District Heating System ◽  
Pump Station ◽  
Pump Equipment

Introduction. The purpose of this investigation is to show what changes introduced in the mathematical model of a district heating system are capable of considerable improving the convergence of simulation results and actual data. The study evaluates the work of heating supply establishments with their customers as well as analysis of the ways of enhancing pump equipment efficiency that allows saving electric energy or increasing output at the same energy consumption. Materials and methods. Engineering acceptance of newly introduced and reconstructed facilities is conducted, heat loads are corrected, disconnections and recurrent connections of indebted consumers are carried out. Studying data submitted by a local heat supply establishment shows that pump seals made from iron and steel are subject accelerated wear in the course of operation. Results. Three variants of the problem solution are suggested: making seals from bronze or stainless steel, prevention of unjustified increase of seal clearances as well as using labyrinth pump seals. This will allow increasing pump equipment efficiency by 5 to 7 % and save about 2 × 105 kW∙h of electrical energy for every pump or increase of output at the same energy consumption. Taking into account that a pump station is a part of the district heating system and unmachined inner surfaces of the pumps have a significant roughness, grinding of these surfaces can improve their hydraulic characteristics of the pumps. In the scope of the suggested method, the entire district heating system is considered not in the situation when actual load is equal to the sum of all the design loads and the pump equipment has manufacturer’s parameters, but accounting actual loads and characteristics. Conclusions. Mathematical model of district heating system heating and hydraulic mode that takes issues mentioned above into consideration would allow simulating joint operation of the heating and hot water supply systems at transient operation modes with higher accuracy.

Predicting Hourly Heating Load in a District Heating System Based on a Hybrid CNN-LSTM Model

2021 ◽  
pp. 110998
Author(s):  
Jiancai Song ◽  
Liyi Zhang ◽  
Guixiang Xue ◽  
YunPeng Ma ◽  
Shan Gao ◽  
...  
Keyword(s):  
District Heating ◽  
Heating System ◽  
District Heating System ◽  
Heating Load

scholarly journals Overview of Solutions for the Low-Temperature Operation of Domestic Hot-Water Systems with a Circulation Loop

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3350
Author(s):  
Theofanis Benakopoulos ◽  
William Vergo ◽  
Michele Tunzi ◽  
Robbe Salenbien ◽  
Svend Svendsen
Keyword(s):  
Low Temperature ◽  
Heat Loss ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Heating Power ◽  
Circulation Loop ◽  
Space Heating ◽  
District Heating System ◽  
Domestic Hot Water

The operation of typical domestic hot water (DHW) systems with a storage tank and circulation loop, according to the regulations for hygiene and comfort, results in a significant heat demand at high operating temperatures that leads to high return temperatures to the district heating system. This article presents the potential for the low-temperature operation of new DHW solutions based on energy balance calculations and some tests in real buildings. The main results are three recommended solutions depending on combinations of the following three criteria: district heating supply temperature, relative circulation heat loss due to the use of hot water, and the existence of a low-temperature space heating system. The first solution, based on a heating power limitation in DHW tanks, with a safety functionality, may secure the required DHW temperature at all times, resulting in the limited heating power of the tank, extended reheating periods, and a DH return temperature of below 30 °C. The second solution, based on the redirection of the return flow from the DHW system to the low-temperature space heating system, can cool the return temperature to the level of the space heating system return temperature below 35 °C. The third solution, based on the use of a micro-booster heat pump system, can deliver circulation heat loss and result in a low return temperature below 35 °C. These solutions can help in the transition to low-temperature district heating.

Experimental and Numerical Study of Mixing in a Hot-Water Storage Tank

2009 ◽  
Vol 131 (1) ◽  
Author(s):  
A. Aviv ◽  
Y. Blyakhman ◽  
O. Beeri ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Numerical Model ◽  
Storage Tank ◽  
Numerical Study ◽  
Tap Water ◽  
Three Dimensional ◽  
Hot Water ◽  
Software Validation ◽  
Water Storage Tank ◽  
Thermal Mixing ◽  
Numerical Investigations

Thermal mixing and stratification are explored numerically and experimentally in a cylindrical tank, which simulates a storage of water heated by a solar collector. The tank is 70cm in height and 24cm in diameter. The inlet and outlet are vertical and located off the centerline of the tank. The study is conducted in a transient mode, namely, the tank is filled with hot water, and as the hot water is being withdrawn, the tap water replaces it in a stratified way or by mixing. The flowrates of 2l∕min, 3l∕min, 5l∕min and 7l∕min, which correspond to superficial velocities of 4.35cm∕min, 6.52cm∕min, 10.87cm∕min, and 15.2cm∕min, are explored. Temperature of hot water ranges within 40–50°C, while the tap water is about 25–27°C. Installation of one and two horizontal baffles above the inlet is examined. Simultaneous experimental and numerical investigations are performed. In the experiment, both flow visualization and temperature measurements are used. Three-dimensional transient numerical simulations are done using the FLUENT 6 software. Validation of the numerical model is achieved by comparison with the experimental results. Then, the numerical model is applied to a study of various possible changes in the system. The results show that at low flowrates, up to a superficial velocity of about 11cm∕min through the tank, the baffles have no effect on tap water mixing with the stored hot water. At higher flowrates, a single horizontal baffle prevents the mixing and preserves the desired stratified temperature distribution in the storage tank.

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.

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