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 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.

Thermoeconomic Cost Analysis of Central Solar Heating Plants Combined With Seasonal Storage

2010 ◽  
Author(s):  
Miguel A. Lozano ◽  
Antonio Anastasia ◽  
Luis M. Serra ◽  
Vittorio Verda
Keyword(s):  
Energy Storage ◽  
Cost Analysis ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Demand ◽  
District Heating ◽  
Solar Heating ◽  
Hot Water ◽  
The European Union ◽  
Internal Flows

The European Union and its Member States have committed themselves to achieving a 20% share of renewable energy by 2020. If the focus remains solely on solar thermal systems for domestic hot water (DHW) preparation, as in Spain, then the solar contribution will be very limited. Central Solar Heating Plants combined with Seasonal Storage (CSHPSS) systems enable high solar fractions of 50% and more. Most CSHPSS demonstration plants in Europe have been built in Central and North Europe, mainly in Denmark, Germany and Sweden. South Europe has little experience. This article presents a thermoeconomic cost analysis of CSHPSS systems. The objective of thermoeconomics is to explain the cost formation process of internal flows and products of energy systems. The costs obtained with thermoeconomics can be used to optimize the design of new plants and to control the production of existing plants. A simulation study on solar assisted district heating systems with high solar fractions and seasonal thermal energy storage was carried out with TRNSYS taking into consideration the meteorological conditions in Zaragoza (Spain). A CSHPSS plant was designed for a district of 500 dwellings with an annual thermal energy demand of 2,905 MWh/year. The process of cost formation has been analyzed considering the very specific features of the CSHPSS designed system: free solar energy, seasonal and DHW thermal energy storage, continuous variation of the operation due to highly variations of solar radiation and energy demands (hourly and seasonal). These features impose important difficulties in the calculation of the costs of internal flows and products in this type of systems.

scholarly journals Perspective on pricing district heating pricing in Sustainable energy systems

2019 ◽  
pp. 46-53
Author(s):  
Louise Ödlund ◽  
Viktor Svensson ◽  
Anna Widengren
Keyword(s):  
Energy Demand ◽  
District Heating ◽  
Energy System ◽  
Climate Impact ◽  
System Perspective ◽  
System Cost ◽  
Systems Perspective ◽  
Heat Demand ◽  
Sustainable Energy Systems ◽  
Energy Utilities

District heating systems play an important role for increased system efficiency and reduced climate impact. However, the heat market is changing in many ways. Some example of that is that current climate change reduces the heat demand for the buildings, more energy efficient houses are being built, and the competition from other heating actors escalates. Increased knowledge and cooperation with customers is therefore crucial for the district heating industry. Today, several real estate companies are considering replacing installed district heating and instead investing in their own heat pump solutions, which means that the energy utilities are facing reduced demand of heat. In this perspective, it is important to open up for increased cooperation between different energy sources. No energy source alone can fulfil a regions total demand of heat. Increase cooperation between different sectors, and a systems perspective with regard to the region's total energy demand, is therefore crucial to alter the use of energy towards more sustainability. Attractive price models that encourage energy efficiency and lead to reduce system cost must be developed embracing broth users and suppliers for the whole energy system. The aim of this study is to show what measure for energy supplier and energy users that leads to both reduced climate impact as well as reduced system cost for the whole energy system. The study analyses price models for district heating and future heat demand in a region. A system perspective is applied using a back-casting angel with a desirable sustainable vision.

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 Solar thermal and wind energy applications: Case study of a small Spanish village

2018 ◽  
Vol 22 (5) ◽  
pp. 2163-2176 ◽  
Author(s):  
Christos Ioakimidis ◽  
Sesil Koutra ◽  
Ali Bagheri ◽  
Konstantinos Genikomsakis
Keyword(s):  
Large Scale ◽  
Peak Load ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Water Tank ◽  
Capital Investments ◽  
District Heating System ◽  
Energy Applications

The present work examines the supply of heating and electricity to the Spanish village of Uruena, using biomass and other local renewable sources as a result of the growing interest worldwide towards the development of sustainable and energy independent small communities. Specifically, this case study considers the design of a district heating system consisting of a solar heating plant, a biomass plant using straw as a sustainable fuel for the base load and an oil boiler for the peak load, coupled with a hot water tank as a thermal energy storage option. Two alternative scenarios are analyzed for electricity generation purposes, namely a system consisting of three small wind turbines and a system with a single large wind turbine. The results show that the cost of large-scale electricity storage depends on the application and often involves significant capital investments.

scholarly journals A machine-learning model for the prediction of aggregated building heating demand from pan-European land-use maps

2021 ◽  
Vol 2042 (1) ◽  
pp. 012019
Author(s):  
G Peronato ◽  
R Boghetti ◽  
J H Kämpf
Keyword(s):  
Land Use ◽  
Energy Demand ◽  
Large Scale ◽  
District Heating ◽  
Building Energy ◽  
Energy Performance ◽  
High Energy ◽  
Urban Energy ◽  
The One ◽  
Land Use Maps

Abstract Aggregated building energy demand is a useful indicator for urban energy planning. It can be used by planners and decision-makers to identify clusters of high energy demand in a given urban area and efficiently plan, for example, district heating networks. Various data sources exist at the pan-European level describing land use and built areas. Combined with statistical data, such maps have been used in previous research for estimating building energy performance aggregated at the hectare level, using engineering assumptions. In this paper, we show that large-scale land-use maps alone can be used for predicting annual building energy demand with an accuracy comparable to the one of previous engineering models. We hence present a preliminary method based on Convolutional Neural Networks at different spatial resolutions. The resulting model was trained and tested in an area of about 170 km1 in Geneva (Switzerland) using a local annual heating demand dataset comprising 16239 buildings. On a 300-m aggregation tile, the obtained mean error (14.3%) is significantly reduced compared to the one of a simple linear model (37.2%). Using solely land-use data, we also achieve similar results for a 100-m tile as those of an engineering model from the literature.

scholarly journals Analysis and comparison of methods for the preparation of domestic hot water from district heating system, selected renewable and non-renewable sources in low-energy buildings

2018 ◽  
Vol 30 ◽  
pp. 03001
Author(s):  
Maciej Knapik
Keyword(s):  
Renewable Energy ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Low Energy ◽  
Energy Sources ◽  
District Heating System ◽  
Domestic Hot Water

The article presents an economic analysis and comparison of selected (district heating, natural gas, heat pump with renewable energy sources) methods for the preparation of domestic hot water in a building with low energy demand. In buildings of this type increased demand of energy for domestic hot water preparation in relation to the total energy demand can be observed. As a result, the proposed solutions allow to further lower energy demand by using the renewable energy sources. This article presents the results of numerical analysis and calculations performed mainly in MATLAB software, based on typical meteorological years. The results showed that system with heat pump and renewable energy sources Is comparable with district heating system.

scholarly journals Comparison of Direct and Indirect Active Thermal Energy Storage Strategies for Large-Scale Solar Heating Systems

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1948 ◽  
Author(s):  
Xiaofeng Guo ◽  
Alain Pascal Goumba ◽  
Cheng Wang
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Demand ◽  
Large Scale ◽  
Solar Heating ◽  
Hot Water ◽  
Simplified Algorithm ◽  
Change Material

Large-scale solar heating for the building sector requires an adequate Thermal Energy Storage (TES) strategy. TES plays the role of load shifting between the energy demand and the solar irradiance and thus makes the annual production optimal. In this study, we report a simplified algorithm uniquely based on energy flux, to evaluate the role of active TES on the annual performance of a large-scale solar heating for residential thermal energy supply. The program considers different types of TES, i.e., direct and indirect, as well as their specifications in terms of capacity, storage density, charging/discharging limits, etc. Our result confirms the auto-regulation ability of indirect (latent using Phase Change Material (PCM), or Borehole thermal storage (BTES) in soil) TES which makes the annual performance comparable to that of direct (sensible with hot water) TES. The charging and discharging restrictions of the latent TES, until now considered as a weak point, could retard the achievement of fully-charged situation and prolong the charging process. With its compact volume, the indirect TES turns to be promising for large-scale solar thermal application.

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.

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