Thermal Storage Systems for District Heating Networks

2010 ◽  
Author(s):  
Vittorio Verda ◽  
Francesco Colella
Keyword(s):  
Electricity Market ◽  
Thermal Load ◽  
Storage Systems ◽  
Fluid Dynamic ◽  
District Heating ◽  
Heating System ◽  
Maximum Load ◽  
Operating Conditions ◽  
District Heating System ◽  
The Impact

District Heating is an efficient way to provide heat to residential, tertiary and industrial users. Heat is often produced by CPH plants, usually designed to provide the base thermal load (40–50% if the maximum load) while the rest is provided by boilers. This choice is made on the basis of economic criteria, in fact the investment cost of a CHP plant is much higher than the cost of boiler, thus its use is convenient when it operates for a large number of hours. The use of storage tanks would permit to increase the annual operating hours of CHP: heat can be produced when the request is low (for instance during the night), stored and then used when the request is high. The use of boilers results partially reduced, thus the thermal load diagram is flattered. Depending on the type of CHP plant this may also affect the electricity generation. All these considerations are crucial in the free electricity market. In this paper, the use of storage systems connected to the district heating systems, is examined. A thermo fluid dynamic model of the tanks is considered in order to calculate the amount of energy actually provided, taking the real operating conditions into account. These considerations are applied to the Turin district heating system, in order to determine the impact of storage systems on the primary energy consumption required to supply heat to the users over the entire heating season.

Reduction of Primary Energy Consumption Through Distributed Thermal Storage in Buildings Connected With a District Heating Network

2014 ◽  
Author(s):  
Giorgia Baccino ◽  
Sara Cosentino ◽  
Elisa Guelpa ◽  
Adriano Sciacovelli ◽  
Vittorio Verda
Keyword(s):  
Energy Consumption ◽  
Thermal Load ◽  
Waste Heat ◽  
Distributed Storage ◽  
Fluid Dynamic ◽  
District Heating ◽  
Thermal Storage ◽  
Primary Energy ◽  
Operating Conditions ◽  
Primary Energy Consumption

One of the possible options for increasing the primary energy efficiency in district heating networks (DHNs) consists in flattening the thermal load diagram of the plants. This can be obtained through thermal storage. Storage generally allows one to increase the percentage of heat produced through CHP plants, waste heat or renewable systems. In this work, a numerical approach to analyze possible effects of distributed storage on the primary energy consumption is presented. This is based on the availability of detailed information about the thermal substations that connect the users to the DHN and a thermo-fluid dynamic model of the network. First, the analysis of a user of the district heating network is proposed in order to show the operating conditions of the heat exchanger in the thermal substation. Then the model of the network is presented and an application is proposed. This application allows us to discuss how the thermal request of a user modifies along the network because of the heat capacity of the network itself and mixing with the mass flow rates at different temperatures. Therefore, the thermal load that the plants should fulfill is different than the simple summation of the thermal request of the users. This tool allows one to link the thermal thermal request of the users to the thermal load of the plant and thus to the global primary energy consumption. It can be then applied to the evaluation of possible variation of thermal request profile of the users.

scholarly journals The use of substations with PCM heat accumulators in district heating system

2018 ◽  
Vol 174 ◽  
pp. 01002 ◽  
Author(s):  
Kinga Nogaj ◽  
Michał Turski ◽  
Robert Sekret
Keyword(s):  
Phase Change Materials ◽  
District Heating ◽  
Heating System ◽  
Economic Benefits ◽  
District Heating System ◽  
Save Energy ◽  
Determination Of Parameters ◽  
Storage Technologies ◽  
The Impact

The main objective of the article is to indicate the directions of development of new generations of supplying buildings with heat, by using phase change materials, referring to the technical possibilities of applying available heat storage technologies. As a detailed objective of the work, the determination of the impact of using a PCM accumulator on the temperature of the heat carrier on the return in the substation of the district heating system was adopted. Range work included determination of parameters of heat distribution network as a function of outdoor air temperature range of -20°C to +12°C. As the analysis object, the heat substation has been selected with the following parameters: supply 80°C and return 60°C. It was found that thanks to the use of PCM accumulators on heat substations, it is possible to save energy by up to approx. 6.7% and achieve economic benefits in the form of a payback period of approx. 13 years. In addition, it was found that the introduction of the PCM accumulator into the heating system allows the return temperature in the heating network to be obtained at a temperature level consistent with the adopted control table for external temperatures of the standard heating season.

scholarly journals Air Quality Planning and the Minimization of Negative Externalities

Resources ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 15 ◽  
Author(s):  
Marco Ravina ◽  
Deborah Panepinto ◽  
Mariachiara Zanetti
Keyword(s):  
Air Quality ◽  
Urban Areas ◽  
District Heating ◽  
Heating System ◽  
Negative Externalities ◽  
District Heating System ◽  
Quality Planning ◽  
Air Quality Planning ◽  
The Impact

The minimization of negative externalities is a key aspect in the development of a circular and sustainable economic model. At the local scale, especially in urban areas, externalities are generated by the adverse impacts of air pollution on human health. Local air quality policies and plans often lack of considerations and instruments for the quantification and evaluation of external health costs. Support for decision-makers is needed, in particular during the implementation stage of air quality plans. Modelling tools based on the impact pathway approach can provide such support. In this paper, the implementation of health impacts and externalities analysis in air quality planning is evaluated. The state of the art in European member states is reported, considering whether and how health effects have been included in the planning schemes. The air quality plan of the Piemonte region in Italy is then considered. A case study is analyzed to evaluate a plan action, i.e., the development of the district heating system in the city of Turin. The DIATI (Dipartimento di Ingegneria dell’Ambiente, del Territorio e delle Infrastrutture) Dispersion and Externalities Model (DIDEM model) is applied to detect the scenario with the highest external cost reduction. This methodology results are extensible and adaptable to other actions and measures, as well as other local policies in Europe. The use of health externalities should be encouraged and integrated into the present methodology supporting air quality planning. Efforts should be addressed to quantify and minimize the overall uncertainty of the process.

scholarly journals Impact of Domestic Hot Water Systems on District Heating Temperatures

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4694
Author(s):  
Tina Lidberg ◽  
Thomas Olofsson ◽  
Louise Ödlund
Keyword(s):  
Low Temperature ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Space Heating ◽  
Circulation System ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Temperature Levels ◽  
The Impact

When buildings become more energy effective, the temperature levels of district heating systems need to be lower to decrease the losses from the distribution system and to keep district heating a competitive alternative on the heating market. For this reason, buildings that are refurbished need to be adapted to suit low-temperature district heating. The aim of this paper is to examine whether four different energy refurbishment packages (ERPs) can be used for lowering the temperature need of a multi-family buildings space heating and domestic hot water (DHW) system as well as to analyse the impact of the DHW circulation system on the return temperature. The results show that for all ERPs examined in this study, the space heating supply temperature agreed well with the temperature levels of a low-temperature district heating system. The results show that the temperature need of the DHW system will determine the supply temperature of the district heating system. In addition, the amount of days with heating demand decreases for all ERPs, which further increases the influence of the DHW system on the district heating system. In conclusion, the DHW system needs to be improved to enable the temperature levels of a low-temperature district heating system.

District Heating Network Modelling for the Analysis of Low-Exergy Sources

2017 ◽  
Author(s):  
Vittorio Verda ◽  
Elisa Guelpa
Keyword(s):  
Power Plants ◽  
Waste Heat ◽  
Fluid Dynamic ◽  
Renewable Energy Sources ◽  
Variable Mass ◽  
District Heating ◽  
Conservation Equation ◽  
Operating Conditions ◽  
Heat Sources ◽  
District Heating System

One of the main advantages of district heating system technology is the possibility of integrating multiple heat sources for domestic heating. In particular, it is often possible exploit low-exergy sources, such as waste heat recovered from industry or from renewable energy sources, that are often affected by time variation of the temperature. A very convenient and useful opportunity for predicting and analyzing district heating network behavior is modelling. Modelling allows to quantify opportunities related to changes in DH (district heating) network design or management, before real implementation. Therefore an important point is the creation of models able to simulate network, also very large and linked to many power plants, working at variable heat production conditions (i.e. variable mass flow rates and temperatures). The goal of this work is to propose a novel approach which combines exergy analysis with a DH network model for evaluating the best DH operating conditions. A thermo-fluid dynamic model based on conservation equation has been adapted for the discussed aims and applied to a network involving different low-exergy heat sources with variable temperatures. An evaluation of the implementation of these sources is provided for the Turin district heating network, which is the largest network in Italy.

STEADY STATE AND DYNAMIC MODELING OF AN INDIRECT DISTRICT HEATING SYSTEM

2010 ◽  
Vol 18 (01) ◽  
pp. 61-75 ◽  
Author(s):  
L. LI ◽  
M. ZAHEERUDDIN ◽  
SUNG-HWAN CHO ◽  
SANG-HOON JUNG
Keyword(s):  
Steady State ◽  
Dynamic Model ◽  
District Heating ◽  
Heating System ◽  
Dynamic Responses ◽  
District Heating System ◽  
Steady State Model ◽  
Heated Floor ◽  
The Impact ◽  
Important System

An indirect district heating system (IDHS) with heated floor area of 851 031 m2 and ten heat exchange stations was modeled in this study. An aggregated steady state model for the system was developed to study the impact of important system parameters. A dynamic model of the IDHS was developed based on energy balance principles. The dynamic model consists of sub-system models such as boiler, pipe network, heat exchanger, terminal heater and zone models. Simulation results of the dynamic responses show that the overall efficiency of the IDHS system is 78.7%, and the two highest heat loss components are the boiler heat losses and the secondary water makeup loss.

Pumping Cost Minimization in an Existing District Heating Network

2013 ◽  
Author(s):  
Adriano Sciacovelli ◽  
Elisa Guelpa ◽  
Vittorio Verda
Keyword(s):  
Control Strategy ◽  
Urban Areas ◽  
Cost Minimization ◽  
Fluid Dynamic ◽  
District Heating ◽  
Primary Energy ◽  
Operating Conditions ◽  
Waste To Energy ◽  
District Heating System ◽  
Partial Load

District heating is expected to significantly contribute to the reduction of primary energy needs for heating in urban areas. This result is obtained through use of such as CHP systems, residual heat from industries or waste-to-energy plants, as well as the integration of renewable energies. The pumping system plays a crucial role and may significantly affect its performances. In this paper a large district heating system is considered. Various operating conditions corresponding with partial load operation are analyzed through a thermo-fluid dynamic model of the network. For each condition, the optimal set point of the various pumps is obtained. The set of optimal operating conditions is finally used to obtain a control strategy for the network. Results show that with respect to conventional control strategy significant reductions in primary energy consumption can be achieved.

scholarly journals Analysis of the Impact of Decreasing District Heating Supply Temperature on Combined Heat and Power Plant Operation

2014 ◽  
Vol 14 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Alona Bolonina ◽  
Genadijs Bolonins ◽  
Dagnija Blumberga
Keyword(s):  
Power Plant ◽  
District Heating ◽  
Heating System ◽  
Combined Heat And Power ◽  
District Heating System ◽  
Heating Systems ◽  
Plant Operation ◽  
Operation Modes ◽  
Power Plant Operation ◽  
The Impact

Abstract District heating systems are widely used to supply heat to different groups of heat consumers. The district heating system offers great opportunities for combined heat and power production. In this paper decreasing district heating supply temperature is analysed in the context of combined heat and power plant operation. A mathematical model of a CHP plant is developed using both empirical and theoretical equations. The model is used for analysis of modified CHP plant operation modes with reduced district heating supply temperature. Conclusions on the benefits of new operation modes are introduced.

scholarly journals The Impact of Optimal Demand Response Control and Thermal Energy Storage on a District Heating System

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1678 ◽  
Author(s):  
Sonja Salo ◽  
Aira Hast ◽  
Juha Jokisalo ◽  
Risto Kosonen ◽  
Sanna Syri ◽  
...  
Keyword(s):  
Demand Response ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Production Costs ◽  
Building Stock ◽  
District Heating System ◽  
Response Control ◽  
Water Storage Tank ◽  
The Impact

Demand response has been studied in district heating connected buildings since the rollout of smart, communicating devices has made it cost-effective to control buildings’ energy consumption externally. This research investigates optimal demand response control strategies from the district heating operator perspective. Based on earlier simulations on the building level, different case algorithms were simulated on a typical district heating system. The results show that even in the best case, heat production costs can be decreased by only 0.7%. However, by implementing hot water thermal storage in the system, demand response can become more profitable, resulting in 1.4% cost savings. It is concluded that the hot water storage tank can balance district heating peak loads for longer periods of time, which enhances the ability to use demand response strategies on a larger share of the building stock.

Thermo-Fluid Dynamic Model of Complex District Heating Networks for the Analysis of Peak Load Reductions in the Thermal Plants

2015 ◽  
Author(s):  
Elisa Guelpa ◽  
Adriano Sciacovelli ◽  
Vittorio Verda
Keyword(s):  
Dynamic Simulation ◽  
Thermal Load ◽  
Storage Systems ◽  
Fluid Dynamic ◽  
District Heating ◽  
Hot Water ◽  
Main Pipeline ◽  
Simulation Approach ◽  
Simulation Tools ◽  
Heating Networks

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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