Optimization of the Thermal Load Profile in District Heating Networks through “Virtual Storage” at Building Level

District heating networks are important infrastructures to provide high efficient heating and domestic hot water to buildings located in urban areas. Modern district heating networks may involve the use of waste heat, renewable sources and heat from cogeneration thermal storage systems. In addition, management is operated through advanced ICT solutions able to minimize the global primary energy consumption and to increase end user awareness. Detailed thermo-fluid dynamic simulation tools can be of extreme importance for the optimal management of modern district heating networks. Some of the issues that simulation tools are requested to face are: peak shaving, selection of the operating temperature, operation in the case of malfunctions, storage management. An important requirement consists in the possibility to perform fast simulations, even in the case of complex networks. This paper aims at presenting a detailed simulation approach that can be applied to large district heating networks. The entire network is represented as constituted by the main pipeline, which may be a tree shaped or a looped network, and various tree shaped subnetworks that distribute water from the main network to each single building. The main pipeline is fully modeled considering fluid flow and transient heat transfer. Subnetworks are simulated using a reduced model obtained from the full model. This modeling approach is applied to the analysis of transient operation of the Turin district heating network. The thermal request of the users is obtained from temperature and mass flow rate measurements at the thermal substations, available each six minutes. Thermo-fluid dynamic simulation allows one obtaining the corresponding thermal load profiles at the various thermal plants. Results show that a peak request is caused by the temperature reduction in the entire system due to the small thermal request at night. Due to the advective transport of water in the network and the thermal losses, the shape and amplitude of the peak at the plant is completely different than that at the users. A comparison between simulations and experimental results shows that the model is able to predict the network operation with good accuracy. Using this simulation approach it is therefore possible to examine the effects of variations, obtained through night attenuation or the installation local storage systems, on the thermal request profiles of some of the users on the global thermal load of the network during the start-up transient. The proposed simulation approach is shown to represent a versatile and important tool for the implementation of advanced management to district heating systems.

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The Impact of Modified EU ETS Allocation Principles on the Economics of CHP-Based District Heating Networks

SSRN Electronic Journal ◽

10.2139/ssrn.1783560 ◽

2011 ◽

Cited By ~ 74

Author(s):

Günther Westner ◽

Reinhard Madlener

Keyword(s):

District Heating ◽

Eu Ets ◽

The Impact ◽

Heating Networks

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RELaTED Project: New Developments on Ultra-Low Temperature District Heating Networks

Proceedings ◽

10.3390/proceedings2020065008 ◽

2020 ◽

Vol 65 (1) ◽

pp. 25

Author(s):

Antonio Garrido Marijuan ◽

Roberto Garay ◽

Mikel Lumbreras ◽

Víctor Sánchez ◽

Olga Macias ◽

...

Keyword(s):

Low Temperature ◽

High Performance ◽

Waste Heat ◽

District Heating ◽

Hot Water ◽

Thermal Systems ◽

Heating Source ◽

Wide Range ◽

Thermal Sources ◽

Heating Networks

District heating networks deliver around 13% of the heating energy in the EU, being considered as a key element of the progressive decarbonization of Europe. The H2020 REnewable Low TEmperature District project (RELaTED) seeks to contribute to the energy decarbonization of these infrastructures through the development and demonstration of the following concepts: reduction in network temperature down to 50 °C, integration of renewable energies and waste heat sources with a novel substation concept, and improvement on building-integrated solar thermal systems. The coupling of renewable thermal sources with ultra-low temperature district heating (DH) allows for a bidirectional energy flow, using the DH as both thermal storage in periods of production surplus and a back-up heating source during consumption peaks. The ultra-low temperature enables the integration of a wide range of energy sources such as waste heat from industry. Furthermore, RELaTED also develops concepts concerning district heating-connected reversible heat pump systems that allow to reach adequate thermal levels for domestic hot water as well as the use of the network for district cooling with high performance. These developments will be demonstrated in four locations: Estonia, Serbia, Denmark, and Spain.

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State estimation models of district heating networks for integrated energy system considering incomplete measurements

Applied Energy ◽

10.1016/j.apenergy.2020.116105 ◽

2021 ◽

Vol 282 ◽

pp. 116105

Author(s):

Suhan Zhang ◽

Wei Gu ◽

Haifeng Qiu ◽

Shuai Yao ◽

Guangsheng Pan ◽

...

Keyword(s):

State Estimation ◽

District Heating ◽

Energy System ◽

Integrated Energy System ◽

Heating Networks ◽

Estimation Models

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Reliability segment design in single-source district heating networks based on valve network models

Sustainable Cities and Society ◽

10.1016/j.scs.2020.102463 ◽

2020 ◽

Vol 63 ◽

pp. 102463

Author(s):

Ding Mao ◽

Peng Wang ◽

Wei Wang ◽

Long Ni

Keyword(s):

District Heating ◽

Network Models ◽

Single Source ◽

Heating Networks

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A Method for Optimizing and Spatially Distributing Heating Systems by Coupling an Urban Energy Simulation Platform and an Energy System Model

Resources ◽

10.3390/resources10050052 ◽

2021 ◽

Vol 10 (5) ◽

pp. 52

Author(s):

Annette Steingrube ◽

Keyu Bao ◽

Stefan Wieland ◽

Andrés Lalama ◽

Pithon M. Kabiro ◽

...

Keyword(s):

District Heating ◽

Energy Systems ◽

Energy System ◽

Heat Pumps ◽

Energy Simulation ◽

Heating Systems ◽

Optimal Amount ◽

Urban City ◽

Urban Energy ◽

Building Level

District heating is seen as an important concept to decarbonize heating systems and meet climate mitigation goals. However, the decision related to where central heating is most viable is dependent on many different aspects, like heating densities or current heating structures. An urban energy simulation platform based on 3D building objects can improve the accuracy of energy demand calculation on building level, but lacks a system perspective. Energy system models help to find economically optimal solutions for entire energy systems, including the optimal amount of centrally supplied heat, but do not usually provide information on building level. Coupling both methods through a novel heating grid disaggregation algorithm, we propose a framework that does three things simultaneously: optimize energy systems that can comprise all demand sectors as well as sector coupling, assess the role of centralized heating in such optimized energy systems, and determine the layouts of supplying district heating grids with a spatial resolution on the street level. The algorithm is tested on two case studies; one, an urban city quarter, and the other, a rural town. In the urban city quarter, district heating is economically feasible in all scenarios. Using heat pumps in addition to CHPs increases the optimal amount of centrally supplied heat. In the rural quarter, central heat pumps guarantee the feasibility of district heating, while standalone CHPs are more expensive than decentral heating technologies.

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Method for Redesign of District Heating Networks within Transition from the 2nd to the 3rd Generation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.657.689 ◽

2014 ◽

Vol 657 ◽

pp. 689-693

Author(s):

Răzvan Corneliu Lefter ◽

Daniela Popescu ◽

Alexandrina Untăroiu

Keyword(s):

District Heating ◽

Design Stage ◽

Heating Systems ◽

Load Duration ◽

Load Duration Curve ◽

District Heating Systems ◽

Consumption Rates ◽

Heat Loads ◽

Heating Networks

Important investmentsare made lately in the area of district heating, as a technology capable ofhelping countries to reach sustainability goals. In Romania, European fundswere spent for transition from the 2nd to the 3rdgeneration of district heating systems. The lack of appropriate monitoringsystems in old district heating systems makes optimisation nowadays very difficult,especially because nominal values used in the first design stage areoverestimated. Realistic nominal heat loads are necessary to make goodestimations of hydraulic parameters to be used for redesign. This studyproposes a method that uses the heat load duration curve theory to identify theappropriate nominal heat loads to be used for redesign. Comparison betweenresults obtained by applying the nominal heat loads of each consumer, as theywere established in the first design stage, and the ones identified by theproposed method are analyzed in a case study. The results show that errors arein the +/- 3% band, between the metered heat consumption rates and the proposedrates. The new method can be used for the sizing of pumps and district heatingnetworks after retrofit, in order to get better adjustments of the circulationpumps and increase of the energy efficiency.

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