Optimal Upgrade of a District Heating Plant Into a Polygeneration Plant Using Biomass as Feedstock

2013 ◽  
Author(s):  
Marianne Salomón ◽  
María F. Gómez ◽  
Andrew R. Martin
Keyword(s):  
District Heating ◽  
Point Of View ◽  
Hot Water ◽  
Detailed Model ◽  
Trade Offs ◽  
Heat Demand ◽  
Fundamental Process ◽  
Investment Cost ◽  
Heating Up ◽  
Heating Plant

This paper aims at evaluating the possible upgrading of an existing district heating plant for production of electricity and pellets. The evaluation is carried out by optimizing the alternatives from the economic, thermodynamic and environmental point of view. In order to examine how the design can be optimized, a detailed model of the process has been elaborated using ASPEN Utilities and Matlab optimization toolbox. The parameters of the polygeneration plant have then been varied in order to examine how optimal economic benefit can be extracted from the biomass streams whilst still meeting the fundamental process demands of the industries and heat demand of the community. A multi-objective optimization has been used to investigate the Pareto-optimal trade-offs that exist between low electricity costs and investment cost. The resulting polygeneration plant designs conclude that it is feasible to produce 18 and 25 MW of power while at the same time supplying the process steam required by the nearby industries and district heating for the community. The results also shown that it is feasible to operate the plant more hours per year by producing pellets and it could be possible to generate additional district heating (up to 25 ton/h of hot water) to cover the demands of a growing community.

scholarly journals A multipurpose test rig for district heating substations: domestic hot water preparation and keep-warm function comparison

2019 ◽  
Vol 111 ◽  
pp. 06012
Author(s):  
Jad Al Koussa ◽  
Rutger Baeten ◽  
Nico Robeyn ◽  
Robbe Salenbien
Keyword(s):  
Heat Exchanger ◽  
Low Temperature ◽  
District Heating ◽  
Hot Water ◽  
Space Heating ◽  
Test Rig ◽  
Domestic Hot Water ◽  
Heat Demand

A well performing District Heating Substation (DHS) is crucial for the efficiency of the District Heating (DH), especially with the shift towards low temperature 4th generation DH systems. For this reason, testing and characterization of commercially available DHSs becomes important to estimate their effect on the DH network. Within the thermo-technical laboratory of EnergyVille, a multipurpose test rig has been built for testing DHSs. In this setup, different DH conditions and heat demand profiles for space heating and for Domestic Hot Water (DHW) can be emulated. Independent tests have been performed on 4 DHSs from three different manufacturers, focused on the DHW preparation for low DH supply temperature and on the stand-by/keep-warm operation of the substations. The latter maintains a certain temperature within the heat exchanger to avoid delays in the delivery of DHW. The results showed that improvements are needed on DHW production for lower DH supply temperatures. Also, enhancements are needed to reduce losses from the keep-warm function. Given that DH systems can have thousands of substations, this will reduce the overall losses and improve the performance of the DH network.

scholarly journals Hybrid solar-biomass system for district heating

2019 ◽  
Vol 85 ◽  
pp. 04006
Author(s):  
Adrian Ilie ◽  
Ion Vişa
Keyword(s):  
Renewable Energy ◽  
Thermal Energy ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Point Of View ◽  
Hot Water ◽  
Energy Sources ◽  
District Heating System ◽  
Heating Systems ◽  
District Heating Systems

The energy used in the built-up environment represents at least 40% of the total energy consumed, out of which, at least 60% is required for heating, cooling and domestic hot water (DHW). Within the European Union, more than 6,000 communities (i.e. over 9%) use district heating systems, the majority of which use the conversion of fossil fuels as a source of energy. This aspect, which is corroborated by the directives of the EU legislation on the use of renewable energy sources and energy performance, imposes the development of new solutions through which the existing district heating systems may be adapted to use renewable energy sources. The solar-thermal systems that are used on a large (district) scale are becoming more and more efficient from the point of view of their feasibility; however, it is almost impossible to create systems that should satisfy the thermal energy demand throughout the four seasons of the year. The hybrid solar-biomass system is becoming the applicable solution for the majority of the communities that have from this potential, since it can secure independence from the point of view of the use of thermal energy. This paper presents the design stages for the implementation of the hybrid solar-biomass systems with a view to identifying the optimal solutions for systems to be integrated into an existing district heating system. A case study (Taberei District in Odorheiu Secuiesc City), which provides a detailed description of the feasible technical solutions, is presented.

Power District Heating at Brno, Czechoslovakia

1944 ◽  
Vol 151 (1) ◽  
pp. 209-213
Author(s):  
W. Kulka
Keyword(s):  
Large Scale ◽  
Boiler House ◽  
District Heating ◽  
Hot Water ◽  
Saturated Steam ◽  
Heat Accumulation ◽  
Secondary Importance ◽  
Pipe Line ◽  
Line Pressure ◽  
Heating Plant

The most effective way to large-scale saving in industrial fuel is the pooling of power and steam consumption. This method, if spread over a wide area, say an industrial town or district, inevitably paves the way to district heating. Ordinary district heating stations, distributing only low-pressure saturated steam or hot water from one central boiler house to consumers in the vicinity, are of but secondary importance when the aim is high overall thermal efficiency in the distribution and consumption of power and heat. Satisfactory economy can only be achieved by installing high-pressure stations and using the pressure drop down to the pipe line pressure for the generation and supply of electric power. Not every community or district is, however, entirely suitable for the establishment of a power-heating plant. The difficulties arise from the geographical position of the industrial areas compared with the location of the mainly residential districts, from the customary times of use of heat and power, and, last but not least, from long-standing habits or traditions in the production and utilization of heat. The power district heating plant built during 1928–30 at Brno, capital of Moravia, Czechoslovakia, is described as an example where considerable difficulties were overcome. Due to its absolute success, the plant subsequently served as a guide in the planning of far larger stations of this kind. The description in the paper embraces the general layout of the plant, followed by details of the boiler house, back-pressure and condensing turbines, piping inside the station, desuperheater, feed arrangement and make-up plant, heat accumulation, and finally the distribution of steam to the consumers. Further, the report gives some important features of the operation, difficulties arising and how they were mastered.

scholarly journals Sizing of biomass-fired ORC cogeneration unit within coal-fired municipal heating plant back fitting project

2019 ◽  
Vol 137 ◽  
pp. 01042
Author(s):  
Jacek Kalina ◽  
Mateusz Świerzewski
Keyword(s):  
District Heating ◽  
Hot Water ◽  
Economic Conditions ◽  
Design Parameters ◽  
Electric Power Output ◽  
Ecological Constraints ◽  
Reference Case ◽  
Water Storage Tank ◽  
Design Characteristics ◽  
Heating Plant

The problem discussed in this paper is optimal sizing of biomass-fired ORC cogeneration units into existing coal-fired district heating plants under given site-specific technical, economic and ecological constraints. In this paper the municipal heating plant in Krosno (Poland) is taken into account as the reference case. Basing on the operational experiences from this unit an optimisation study has been performed in order to examine the influence of current economic and legal conditions on the optimal design characteristics of the plant. Different electricity, biomass and coal prices are taken into account as well as the influence of the EUA (European Emission Allowance) price is examined. There are taken into account thermal energy storage and sale of electricity on balancing market. It has been found that in the studied case the implementation of hot water storage tank moves the optimal electric power output slightly towards higher values. On the other hand only a small improvement of financial performance has been gained. The results reveal importance of the optimisation of design parameters as well as the dependence of the plant’s size and structure on local economic conditions.

scholarly journals Specifying DHW heat demand profiles according to operational data: enhancing quality of a DH system model

2021 ◽  
Vol 263 ◽  
pp. 04016
Author(s):  
Stanislav Chicherin ◽  
Andrey Zhuikov ◽  
Mikhail Kolosov ◽  
Lyazzat Junussova ◽  
Madina Aliyarova ◽  
...  
Keyword(s):  
Energy Demand ◽  
Large Scale ◽  
Thermal Inertia ◽  
District Heating ◽  
Hot Water ◽  
Fourth Generation ◽  
Optimal Size ◽  
Energy Company ◽  
Heat Demand ◽  
Operational Data

For a DH network a meticulous analysis is required to detect a correlation of a reduction in energy demand from one year to another. The factors, which lead to such inconsistency, force an energy company (1) to modernize equipment at a consumer side and (2) to lower network operating temperatures. It results into so called fourth generation district heating (4GDH). The current research focuses on large-scale DH systems and DHW as second largest share of heat demand. The heat delays, thermal inertia and DHW consumption patterns are specified further since they might represent a natural heating accumulator. In this case, daily flow changes are considered, as they influence a DH system performance and desirable TES capacity. However, more precise profiles can be achieved by detecting the actual flow curve, and measuring the temperature difference between substation supply and return line. The dimensioning of DH systems requires comprehensive understanding of simultaneity factors. Thus, we consider substations with DHW preparation to choose the optimal size of the heat distribution network according to the new method. Case study is a DH system in Omsk, which includes residential houses (both SH and DHW coverage), and university buildings (more demand results from process heat). The operation of the system was studied for the period from the 1st of January to 31st of December 2020. We suggest a TES with a capacity of 0.04 MWh; based on the traditional temperature range, the volume is about 0.5 m3. Daily compensation time is 2-3 hours, when there is a reduction in the supply flow rate of 1500 t/h with minimum DH plant make-up. The entire DH system requires about 400 t of hot water make-up to reach the quasi-steady state conditions after the night DHW shutdown. Using the threshold of the traditional model, it hardly fits an operational value - it is better set according to novel method (0.1 MW). For similar relations between circulation and DHW flow rates, the systems with a HE result in higher circulating flows than the substations with no one. The consumer benefit from consuming DHW and heat according to more accurate profiles accounts 1.72 billion USD. It is quantified by considering avoiding using a back-up electricity source to ensure DHW service when a DH plant supplies enough heat. Moreover, if a TES is controlled according to the method detailed, it alleviates the stress for intermittent operation by compensating the transients of SH and DHW loads. 4GDH concept should be considered according to: (1) the operational data, (2) new DHW demand assessments, and (3) using TES to buffer peaks.

scholarly journals APPLICATION OF DIMENSIONAL ANALYSIS IN HEAT LOSS DETERMINING IN DISTRICT HEATING SYSTEMS

2016 ◽  
Vol 56 (2) ◽  
pp. 81 ◽  
Author(s):  
Mária Čarnogurská ◽  
Romana Dobáková ◽  
Miroslav Příhoda
Keyword(s):  
Heat Loss ◽  
Dimensional Analysis ◽  
Water Distribution ◽  
Functional Dependence ◽  
District Heating ◽  
Mathematic Model ◽  
Point Of View ◽  
Hot Water ◽  
Wide Range ◽  
Complex Criterion

Existing procedures for determining the heat loss in heat distribution use balance relations, or rather they are based on the theory of heat and mass transfer. Dimensional analysis enables a new point of view that demonstrated the functionality of heat loss from selected physical quantities that contribute to heat loss. The solution provides one complex criterion and four simplex criteria of similarity. Transforming these criteria of similarity leads to the formulation of the functional dependence of only two criteria, on the basis of which the amount of heat loss can be determined. The resulting criterial dependency is simple, and is calculated in this paper for a pipe one meter in longth. The mathematic model for demonstrating the heat loss is of universal validity, and applies to a wide range of piping used for hot water distribution. However, for each nominal diameter of piping it is necessary to take into account the mutual dependency of the dimensionless arguments <em>p</em><sub>5</sub> on <em>p</em><sub>1</sub>, the form of which is always different. In the paper, this dependency is demonstrated for two nominal diameters DN65 and DN125.

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