scholarly journals A Thermo-Economic and Emissions Analysis of Different Sanitary-Water Heating Units Embedded Within Fourth-Generation District-Heating Systems

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Primož Poredoš ◽  
Boris Vidrih ◽  
Andrej Kitanovski ◽  
Alojz Poredoš
Keyword(s):  
Local Heating ◽  
District Heating ◽  
Primary Energy ◽  
Hot Water ◽  
Fourth Generation ◽  
Heating Unit ◽  
Energy Factor ◽  
Heating Systems ◽  
District Heating Systems ◽  
The Eu

This paper presents the results of a thermo-economic (TE), primary-energy-factor and CO2-equivalent (CO2 (eq)), emissions-sensitivity analysis for the preparation of sanitary hot water (SHW) in fourth-generation district-heating systems. The annual required additional heat for the SHW provided by a local heating unit, based on an air-to-water heat pump (AWHP), a natural-gas boiler (NG boiler), and an electrical resistance heater (ERH), was determined using a trnsys simulation. Additionally, the seasonal performance factor (SPF) of the HP under consideration was determined. The study considered three possible supply temperatures, i.e., 35, 40, and 45 °C. The results show that a local heating unit based on an AWHP is most efficient in terms of the used primary energy (PE) and CO2 (eq) emissions. This unit is also the second best in terms of TE performance. The unit based on a NG boiler is much more appropriate than an ERH unit in terms of both the primary energy factor (PEF) and the CO2 (eq) emission factors for an electricity generation mix (EGM) that has values higher than the average for the EU-28. The heat generated by this NG unit is also cheaper than the heat produced by an ERH based on the average price for electricity in the EU-28.

scholarly journals Utilizing Sewage Wastewater Heat in District Heating Systems in Serbia - Effects on Sustainability

2021 ◽  
Author(s):  
Marija Živković ◽  
Dejan Ivezic
Keyword(s):  
Energy Source ◽  
Wastewater Treatment ◽  
Carbon Dioxide Emission ◽  
District Heating ◽  
Primary Energy ◽  
Energy Sources ◽  
Heating Systems ◽  
Current State ◽  
District Heating Systems ◽  
Treatment Facilities

Abstract Transformation of the heating sector is recognized as being essential for ensuring reliable and affordable energy services provided with reduced consumption of energy sources, diminished impact on the environment and less import dependency. The possibility of utilizing energy sources that otherwise would be wasted needs to be considered and treated as a big advantage of district heating systems. Despite many advantages, sewage wastewater heat is still a mostly unused resource at the global level and a totally unused energy source in Serbia, while data about the potential of this energy source are lacking. This research proposes a methodology for the determination of the technical potential of waste heat from wastewater treatment facilities for use in district heating systems by heat pump application. Data from existing wastewater treatment facilities are used for providing data for replication in cities without wastewater treatment plants but with district heating systems. An estimation of the recoverable heat energy potential of wastewater is used for evaluation of some effects that could be obtained through its full utilization for heat production in the existing district heating systems. Three groups of indicators are selected for analysis focusing on district heating systems' energy performance (primary energy factor, specific heat consumption per degree day and heating area), the security of energy supply (import dependency, Shannon Wiener diversification index, the share of renewables) and environmental impact (carbon dioxide emission coefficient). Values of the selected indicators are determined for the current state of district heating systems and for the possible future state that could be achieved after full utilization of sewage wastewater potential. The proposed methodology is applied to Serbia, as a case study. It has been shown that all analyzed indicators for the projected future would have more preferable values compared to the values that correspond to the current state of the district heating systems. The use of this renewable energy source should provide primary energy savings of 5% per year, reduction of carbon dioxide emission of 6.5% per year, reduction of import dependency of DH systems of 9.8% and improved diversification of energy sources of 21%.

scholarly journals Exergy Analyses of Low-Temperature District Heating Systems With Different Sanitary Hot-Water Boosters

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 388
Author(s):  
Poredoš ◽  
Kitanovski ◽  
Poredoš
Keyword(s):  
Low Temperature ◽  
Winter Season ◽  
District Heating ◽  
Intersection Point ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Heating Systems ◽  
District Heating Systems ◽  
Different Types ◽  
Exergy Analyses

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.

scholarly journals Energy efficient modernization of KVG and TGV boilers

2021 ◽  
Vol 36 ◽  
pp. 22-35
Author(s):  
P. Glamazdin ◽  
D. Glamazdin
Keyword(s):  
Operating Time ◽  
Small Diameter ◽  
District Heating ◽  
Hot Water ◽  
Automation System ◽  
Convective Heating ◽  
Optimized Design ◽  
Efficient Design ◽  
Heating Systems ◽  
District Heating Systems

At present, the district heating systems of Ukrainian cities are in a critical state. They need significant modernization. This especially applies to very important components of district heating systems – heating water boilers. Unsatisfactory condition of boilers is mainly due to the obsolescence of basic equipment, including boilers. The operating time of them exceeds the passport lifetime. There ia a lack of modern automation, especially in terms of controlling operating modes. Nominal power of them exceeds the real heat loads. The range of hot water boilers used is not large. These are low-power boilers of the series NDIST, "Universal", "Energiia", "Fakel" and others, medium-power boilers of the series TVG and KVG and high-power boilers of series PTVM and KVGM. According to their prevalence, special attention should be paid to boilers of the series TVG and KVG. The series are installed on quarter boiler houses. The boilers of these series have an efficient design of the furnace volume and an optimized design of the convective part. Nevertheless, in terms of automation, gas supply and air supply systems, they no longer meet today's requirements. They are outdated comparing to the achieved level of technical solutions. The article discusses the main shortcomings of the design of boilers: insufficient durability of the gas collector in the hearth burner, small diameter of the pipes of the convective part and the use of fireclay materials in the setting of the burners. The first two shortcomings were overcome by the developers by the increase in the diameter of the pipes of convective packages and the modernization of MPIG-3 hearth burners. The third shortcoming should be overcomed by replacing the setting with a modern one during off-season repairs. Reserves for improving the energy efficiency of boilers of these series are found. To do this, it is necessary to install additional convective heating surfaces (economizers or air-heaters), replace the setting and equip the boilers with a modern automation system with cascading the burners. It allows improving efficiency up to 94...95 % and environmental performance according to the modern requirements.

scholarly journals APLICATION OF REGRESSION ANALYSIS IN FEASIBILITY STUDIES OF CONSUMER CONNECTION TO DISTRICT HEATING SYSTEMS

2021 ◽  
Vol XXVIII (4) ◽  
pp. 121-132
Author(s):  
Corina Chelmenciuc ◽  
◽  
Constantin Borosan ◽  
Vadim Lisnic ◽  
◽  
...  
Keyword(s):  
Regression Analysis ◽  
Urban Areas ◽  
District Heating ◽  
Feasibility Studies ◽  
Heating System ◽  
Primary Energy ◽  
Energy Resources ◽  
District Heating System ◽  
Heating Systems ◽  
District Heating Systems

Nowadays, both globally and in Europe, and nationally, there is a tendency to promote district heating systems to the detriment of individual ones to heat dwellings in urban areas. The need to develop the DHSs is indisputable considering the topicality of global warming, the depletion of the primary energy resources and the energy efficiency trend. This article presents the method of applying regression analysis in feasibility studies for the projects of new heat consumers connection to the district heating system (hereinafter – DHS) or previously disconnected consumers reconnection via individual heating points (hereinafter – IHP) when the necessary investments are to be borne by the DHS operator, and the thermal energy is produced in cogeneration. At the same time, it is demonstrated that there is a direct and linear correlation between fuel consumption and electricity and heat produced in cogeneration at CHP plant.

scholarly journals Trends in the development of the district heating systems of Ukraine

2021 ◽  
Vol 2021 (1) ◽  
pp. 52-59
Author(s):  
V.O. Derii ◽  
Keyword(s):  
Thermal Energy ◽  
Heat Supply ◽  
District Heating ◽  
Hot Water ◽  
Low Carbon ◽  
Heating Systems ◽  
Fuel Balance ◽  
Generation Structure ◽  
District Heating Systems ◽  
Low Carbon Development

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

Development of Overground Hot Water Stores in Segmental Construction for Solar and District Heating Systems Within the Project OBSERW

2017 ◽  
Author(s):  
Thorsten Urbaneck ◽  
Fabian Findeisen ◽  
Jan Markus Mücke ◽  
Bernd Platzer ◽  
Dominik Bestenlehner ◽  
...  
Keyword(s):  
District Heating ◽  
Hot Water ◽  
Heating Systems ◽  
District Heating Systems
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