scholarly journals Application of thermohydraulic dispatcher in low temperature district heating systems for decreasing heat carrier transportation energy cost and increasing reliability of heat supply

2017 ◽  
Vol 891 ◽  
pp. 012167 ◽  
Author(s):  
Y V Yavorovsky ◽  
D O Romanov ◽  
V V Sennikov ◽  
I A Sultanguzin ◽  
A S Malenkov ◽  
...  
2018 ◽  
Vol 284 ◽  
pp. 1385-1389 ◽  
Author(s):  
Y.V. Yavorovsky ◽  
D.O. Romanov ◽  
V.G. Khromchenkov

This article is concerned with the research of thermos-hydraulic separators and dispatchers (THD) in heat supply systems and focuses on the experimental part of the research. Тhe experiments allowed to develop the ANSYS Fluent model in terms of accuracy and veracity. The developed model allows to predict operation of THD in different regimes. The results may be used for designing the systems with THD. Such systems may be low temperature district heating systems, where THD allow to hydraulically separate the circuits from each other.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3218
Author(s):  
Pedro Durán ◽  
Herena Torio ◽  
Patrik Schönfeldt ◽  
Peter Klement ◽  
Benedikt Hanke ◽  
...  

There are 1454 district heating systems in Germany. Most of them are fossil based and with high temperature levels, which is neither efficient nor sustainable and needs to be changed for reaching the 2050 climate goals. In this paper, we present a case study for transforming a high to low temperature district heating system which is more suitable for renewable energy supply. With the Carnot Toolbox, a dynamic model of a potential district heating system is simulated and then transformed to a low temperature supply. A sensitivity analysis is carried out to see the system performance in case space constrains restrict the transformation. Finally, an economic comparison is performed. Results show that it is technically possible to perform the transformation until a very low temperature system. The use of decentralized renewable sources, decentralized heat storage tanks and the placement of a heat pump on each building are the key points to achieve the transformation. Regarding the sensitivity analysis, the transformation is worth doing until the seasonal storage and solar collector field sizes are reduced to 60% and 80% of their values in the reference case, respectively. The economic analysis shows, however, that it is hard for highly efficient low temperature renewable based heat networks to compete with district heating systems based on a centralized fossile CHP solution. Thus, though the presented transformation is technically possible, there is a strong need to change existing economic schemes and policies for fostering a stronger promotion of renewable energy policies in the heat sector.


Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 388
Author(s):  
Poredoš ◽  
Kitanovski ◽  
Poredoš

This paper presents an exergy-efficiency analysis of low-temperature district heating systems (DHSs) with different sanitary hot-water (SHW) boosters. The required temperature of the sanitary hot water (SHW) was set to 50 °C. The main objective of this study was to compare the exergy efficiencies of a DHS without a booster to DHSs with three different types of boosters, i.e., electric-, gas-boiler- and heat-pump-based, during the winter and summer seasons. To achieve this, we developed a generalized model for the calculation of the exergy efficiency of a DHS with or without the booster. The results show that during the winter season, for a very low relative share of SHW production, the DHS without the booster exhibits favorable exergy efficiencies compared to the DHSs with boosters. By increasing this share, an intersection point above 45 °C for the supply temperatures, at which the higher exergy efficiency of a DHS with a booster prevails, can be identified. In the summer season the results show that a DHS without a booster at a supply temperature above 70 °C achieves lower exergy efficiencies compared to DHSs with boosters at supply temperatures above 40 °C. The results also show that ultra-low supply and return temperatures should be avoided for the DHSs with boosters, due to higher rates of entropy generation.


2021 ◽  
Vol 2021 (1) ◽  
pp. 52-59
Author(s):  
V.O. Derii ◽  

We considered trends in the development of district heating systems (DHS) in Europe and Ukraine. It was established that DHS are widely used and make a significant contribution to the heat supply of European countries. In the European Union as a whole, the share of DHS is 13%, and there are plans to increase it to 50% in 2050 with a wide use of cogeneration and renewable sources of energy, including environmental energy with using heat pumps. Ukraine is one of the countries with a high level of DHS, but, at present, there are negative trends to reducing their contribution to the total heat supply for heating and hot water supply – from 65.2% in 2014 to 52% in 2017. In several cities, DHS ceased to function at all. The main equipment of the DHS of Ukraine is physically worn out and technologically obsolete and needs to be renewed by means of wide reconstruction, modernization, and technological re-equipment. We determined factors and the level of their influence on the demand in thermal energy of DHS. It was established that the factors reducing demand have a much greater potential. We created forecasts of demand for thermal energy, fuel balance, and the structure of DHS generation by 2050. It is shown that the demand for thermal energy from DHS will decrease and reach about 35 million Gcal in 2050. To ensure the low-carbon development of Ukraine in the structure of thermal energy generation in DHS, the use of coal-fired CHPs and boilers, as well as boilers on petroleum products will be significantly reduced. The share of natural gas in the fuel balance of DHS of Ukraine will also decrease, but it will be the main fuel for the period of technological transformation of generating capacities under conditions of the low-carbon development of Ukraine. The use of technologies for the production of thermal energy from biomass, waste, environment, and electricity will gradually increase, and in 2050, using these sources will produce about 23.8 million Gcal, which is more than 60% of the total thermal energy of DHS. Keywords: district heating systems, thermal energy, factors of influence, demand, fuel balance, generation structure


2020 ◽  
pp. 81-97
Author(s):  
O Shelimanova ◽  
◽  
A. Kolienko ◽  

Ensuring optimal hydraulic and thermal regimes in district heating systems (DHS) in the regulation of heat supply is an important factor in improving the energy and economic efficiency of DHS. In addition, high efficiency of the HS system is a factor that can ensure the preservation of its vital functions. Solving the problem of increasing the energy efficiency of the heat supply system is a complex problem that requires changes at all stages of heat transformation: in the energy source, heating networks and subscriber heating systems of heat consumers. The purpose of this study is to identify the impact of heat dissipation control processes in district heating systems on their energy and economic efficiency, provide recommendations for improving control processes taking into account modern challenges and regulatory requirements, analyze heat dissipation temperature schedules and select the optimal temperature schedule. It is shown that the optimal is the combined quantitative and qualitative regulation of heat release, which should be carried out both at the energy source and at consumers. The paper considers the possibility of using combined control systems in the existing district heating systems of Ukrainian cities. It is shown that the achievement of high energy efficiency is possible only with the introduction of automatic individual heating points with weather control and pressure drop regulators at the inlet to the buildings in the subscriber heating systems. Calculations of the amount of heat consumption reduction of centralized heat supply systems with the introduction of optimal control systems are performed.


Author(s):  
A. V. Kiryukhin ◽  
V. M. Sugrobov

The forecast geothermal resources of Kamchatka are sufficient to generate 3900 MW of electrical energy. The same resources for heat supply are estimated at a capacity of 1350 MWt (thermal). Thermohydrodynamic TOUGH2 modeling of exploitation of already identified productive hydrogeothermal reservoirs with installed energy properties allows us to predict: 1) the possibility of increasing the electrical performance of already operating areas of the Mutnovsky field up to 105 MW and the Pauzhetsky field up to 11 MW using binary technologies; 2) the possibility of increasing heat generation at the Paratunskoye field with submersible pumps up to 216 MWt, which will fully ensure the heat consumption of the district heating systems of Petropavlovsk-Kamchatsky.


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