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.

MEASURED ENERGY CONSUMPTION ANALYSIS OF A DISTRICT HEATING SYSTEM UNDER DIFFERENT TEMPERATURE CONTROL STRATEGIES

2014 ◽  
Vol 22 (02) ◽  
pp. 1450008 ◽  
Author(s):  
SUNG-HWAN CHO ◽  
SEONG-KI HONG ◽  
SANG-HO CHOI ◽  
M. ZAHEERUDDIN
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Control Methods ◽  
Outdoor Temperature ◽  
District Heating System ◽  
Partial Load ◽  
Hot Water Supply

In this study, the secondary side measured energy consumption of a district heating system (DHS) with different hot water supply temperature control methods was compared. Two control methods were evaluated: an outdoor temperature reset control (OTRC) and an outdoor temperature predictive control (OTPC). While the OTRC strategy has been widely used for energy savings in DHS, the results show that the OTPC strategy resulted in higher energy savings. In general, the OTPC strategy maintained lower supply water temperature, and thereby reduced standby losses and increased overall heat transfer rate to the heated spaces due to higher water mass flow rate to the spaces. During the actual energy consumption monitoring, the OTPC strategy saved about 6.6% more energy compared to that of OTRC strategy. Also, it was found that under partial load conditions, such as during the daytime, the fluctuations in hot water supply temperature with OTRC were more severe than OTPC strategy. Overall, the results showed that the OTPC strategy gave better control and was more stable under full load and partial load conditions.

A New Type of District Heating System Based on Distributed Absorption Heat Pumps

2009 ◽  
Author(s):  
Lin Fu ◽  
Yan Li
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
District Heating ◽  
Heating System ◽  
Heat Pumps ◽  
Hot Water ◽  
Conventional Heating ◽  
Low Grade ◽  
District Heating System ◽  
New Approach

This paper presents a new approach to utilize geothermal energy with absorption heat pump in district heating system. The heat pump is driven by the temperature-difference between primary and secondary heating loops. In this method, the low-grade thermal energy can be used in district heating system effectively, as a result, the heating capacity and energy efficiency of district heating system can be improved more than 20%. On one hand, it could relieve the existing dilemma (shortage) of central heat source, as well enhance the delivery capacity of heating network dramatically. On the other hand, heating cost may be reduced remarkably, due to the reduction in both coal consumption of central heat and energy consumption of delivery pump. Firstly, this paper introduces the district heating method based on distributed absorption heat pumps through the analysis on the parameter characteristics of low-grade energy, hot water of primary and secondary heating network, as well as the operation parameters of absorption heat pumps. Secondly, an economic and energy consumption analysis was discussed by comparing the new approach with conventional heating system. Finally, this paper presents several system configurations, discusses the operation strategies in various conditions, and proposes the operation modes for heating season.

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.

scholarly journals Advanced Control of a District Heating System with High Residential Domestic Hot Water Demand

2020 ◽  
Vol 160 ◽  
pp. 01004 ◽  
Author(s):  
Stanislav Chicherin ◽  
Lyazzat Junussova ◽  
Timur Junussov
Keyword(s):  
Energy Demand ◽  
Energy Use ◽  
District Heating ◽  
Heating System ◽  
Primary Energy ◽  
Hot Water ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Extreme Load ◽  
Flow Controller

Proper adjustment of domestic hot water (DHW) load structure can balance energy demand with the supply. Inefficiency in primary energy use prompted Omsk DH company to be a strong proponent of a flow controller at each substation. Here the return temperature is fixed to the lowest possible value and the supply temperature is solved. Thirty-five design scenarios are defined for each load deviation index with equally distributed outdoor temperature ranging from +8 for the start of a heating season towards extreme load at temperature of -26°C. All the calculation results are listed. If a flow controller is installed, the customers might find it suitable to switch to this type of DHW supply. Considering an option with direct hot water extraction as usual and a flow controller installed, the result indicates that the annual heat consumption will be lower once network temperatures during the fall or spring months are higher. The heat load profiles obtained here may be used as input for a simulation of a DH substation, including a heat pump and a tank for thermal energy storage. This design approach offers a quantitative way of sizing temperature levels in each DH system according to the listed methodology and the designer's preference.

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 Biomass consumption in residential sector of Ukraine in 2007–2016

2019 ◽  
Vol 112 ◽  
pp. 02006
Author(s):  
Viacheslav Antonenko ◽  
Sofiia Levinska
Keyword(s):  
District Heating ◽  
Decisive Role ◽  
Heating System ◽  
Regional Level ◽  
Hot Water ◽  
District Heating System ◽  
Residential Sector ◽  
Statistical Monitoring ◽  
Direct Emission ◽  
Self Production

Residential sector plays a decisive role in the bioenergy sector growth in Ukraine. Larger half of biomass used by households comes from so-called self-production, which is problematic for the statistical monitoring. State Statistics do not publish detailed fuel mix reports on regional level. In this article we are providing a detailed data on fuel mix used by the households at regional level during 2007– 2016 and determine the biofuel self-production amount. The facilities that are direct emission sources and are the final fuel consumers, including individual heating/hot water boilers/stoves out of district heating system and individual cookers are considered in detail.

scholarly journals Impact of Domestic Hot Water Systems on District Heating Temperatures

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4694
Author(s):  
Tina Lidberg ◽  
Thomas Olofsson ◽  
Louise Ödlund
Keyword(s):  
Low Temperature ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Space Heating ◽  
Circulation System ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Temperature Levels ◽  
The Impact

When buildings become more energy effective, the temperature levels of district heating systems need to be lower to decrease the losses from the distribution system and to keep district heating a competitive alternative on the heating market. For this reason, buildings that are refurbished need to be adapted to suit low-temperature district heating. The aim of this paper is to examine whether four different energy refurbishment packages (ERPs) can be used for lowering the temperature need of a multi-family buildings space heating and domestic hot water (DHW) system as well as to analyse the impact of the DHW circulation system on the return temperature. The results show that for all ERPs examined in this study, the space heating supply temperature agreed well with the temperature levels of a low-temperature district heating system. The results show that the temperature need of the DHW system will determine the supply temperature of the district heating system. In addition, the amount of days with heating demand decreases for all ERPs, which further increases the influence of the DHW system on the district heating system. In conclusion, the DHW system needs to be improved to enable the temperature levels of a low-temperature district heating system.

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