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The European Union’s ambitious climate targets necessitate substantial reductions in greenhouse gas emissions, particularly within the heating and cooling sector, which accounts for a significant portion of energy consumption. District Heating and Cooling (DHC) systems emerge as a key solution for decarbonizing this sector by enabling high efficiency heat production and the integration of renewable and carbon-neutral energy sources. Despite the potential inherent in DHC systems, their utilization is limited, partly due to challenges associated with network topology selection. This master’s thesis addresses the optimization of District Heating Network layout expansion while tackling these challenges. Situated within the framework of an European funded project coordinated by EIFER, the research aims to develop an algorithm for modeling and planning the expansion of DHN networks, considering geographical location of pipes and heat production and consumption nodes. Building upon the Automatic Network Drawing Algorithm (ANDA) tool provided by EIFER, the project seeks to enhance it to generate expansion scenarios incorporating loops, a feature critical for network robustness absent in the current output. The tool pandapipes is used for fluid system modeling, effectively modelinghydraulics and heat through network elements such as heat producer, substationsand pipes. The algorithm’s core feature is to strategically determine optimallocations along initial tree-like network expansions to incorporate loops. Variousheuristic approaches are tested to identify the most efficient expansion strategies,subsequently adding new lines to minimize total costs, encompassing both capitaland operational expenses. Real-world data from a District Heating Network inMilan validate the algorithm’s capabilities., Europeiska unionens ambitiösa klimatmål kräver avsevärda minskningar av utsläppen av växthusgaser, särskilt inom värme- och kylsektorn, som står för en betydande del av energiförbrukningen. Fjärrvärme- och fjärrkylasystem (DHC) framstår som en nyckellösning för att minska koldioxidutsläppen i denna sektor genom att möjliggöra högeffektiv värmeproduktion och integrering av förnybara och koldioxidneutrala energikällor. Trots potentialen som finns i DHC-system är deras användning begränsad, delvis på grund av utmaningar i samband med val av nätverkstopologi. Denna masteruppsats behandlar optimering av utbyggnaden av fjärrvärmenätets layout samtidigt som man tacklar dessa utmaningar. Beläget inom ramen för ett europeiskt finansierat projekt koordinerat av EIFER, syftar forskningen till att utveckla en algoritm för modellering och planering av utbyggnaden av DHN-nät, med hänsyn till den geografiska placeringen av rör och värmeproduktions- och förbrukningsnoder. Med utgångspunkt i verktyget Automatic Network Drawing Algorithm (ANDA) från EIFER, försöker projektet förbättra det för att generera expansionsscenarier med slingor, en funktion som är avgörande för nätverkets robusthet som saknas i den aktuella utgången. Verktyget pandapipes används för modellering av vätskesystem, effektiv modellering av hydraulik och värme genom nätverkselement som värmeproducent, transformatorstationer och rör. Algoritmens kärnfunktion är att strategiskt bestämma optimala platser längs initiala trädliknande nätverksutbyggnader för att införliva slingor. Olika heuristiska tillvägagångssätt testas för att identifiera de mest effektiva expansionsstrategierna, och sedan läggas till nya linjer för att minimera de totala kostnaderna, som omfattar både kapital- och driftskostnader. Verkliga data från ett fjärrvärmenätverk i Milano validerar algoritmens kapacitet.

The European Union’s ambitious climate targets necessitate substantial reductions in greenhouse gas emissions, particularly within the heating and cooling sector, which accounts for a significant portion of energy consumption. District Heating and Cooling (DHC) systems emerge as a key solution for decarbonizing this sector by enabling high efficiency heat production and the integration of renewable and carbon-neutral energy sources. Despite the potential inherent in DHC systems, their utilization is limited, partly due to challenges associated with network topology selection. This master’s thesis addresses the optimization of District Heating Network layout expansion while tackling these challenges. Situated within the framework of an European funded project coordinated by EIFER, the research aims to develop an algorithm for modeling and planning the expansion of DHN networks, considering geographical location of pipes and heat production and consumption nodes. Building upon the Automatic Network Drawing Algorithm (ANDA) tool provided by EIFER, the project seeks to enhance it to generate expansion scenarios incorporating loops, a feature critical for network robustness absent in the current output. The tool pandapipes is used for fluid system modeling, effectively modelinghydraulics and heat through network elements such as heat producer, substationsand pipes. The algorithm’s core feature is to strategically determine optimallocations along initial tree-like network expansions to incorporate loops. Variousheuristic approaches are tested to identify the most efficient expansion strategies,subsequently adding new lines to minimize total costs, encompassing both capitaland operational expenses. Real-world data from a District Heating Network inMilan validate the algorithm’s capabilities., Europeiska unionens ambitiösa klimatmål kräver avsevärda minskningar av utsläppen av växthusgaser, särskilt inom värme- och kylsektorn, som står för en betydande del av energiförbrukningen. Fjärrvärme- och fjärrkylasystem (DHC) framstår som en nyckellösning för att minska koldioxidutsläppen i denna sektor genom att möjliggöra högeffektiv värmeproduktion och integrering av förnybara och koldioxidneutrala energikällor. Trots potentialen som finns i DHC-system är deras användning begränsad, delvis på grund av utmaningar i samband med val av nätverkstopologi. Denna masteruppsats behandlar optimering av utbyggnaden av fjärrvärmenätets layout samtidigt som man tacklar dessa utmaningar. Beläget inom ramen för ett europeiskt finansierat projekt koordinerat av EIFER, syftar forskningen till att utveckla en algoritm för modellering och planering av utbyggnaden av DHN-nät, med hänsyn till den geografiska placeringen av rör och värmeproduktions- och förbrukningsnoder. Med utgångspunkt i verktyget Automatic Network Drawing Algorithm (ANDA) från EIFER, försöker projektet förbättra det för att generera expansionsscenarier med slingor, en funktion som är avgörande för nätverkets robusthet som saknas i den aktuella utgången. Verktyget pandapipes används för modellering av vätskesystem, effektiv modellering av hydraulik och värme genom nätverkselement som värmeproducent, transformatorstationer och rör. Algoritmens kärnfunktion är att strategiskt bestämma optimala platser längs initiala trädliknande nätverksutbyggnader för att införliva slingor. Olika heuristiska tillvägagångssätt testas för att identifiera de mest effektiva expansionsstrategierna, och sedan läggas till nya linjer för att minimera de totala kostnaderna, som omfattar både kapital- och driftskostnader. Verkliga data från ett fjärrvärmenätverk i Milano validerar algoritmens kapacitet.

The construction of the Southeast city district in Uppsala will start in 2025 with plans to be completed in 2050. When a new district is built, there is an opportunity to explore the best possible solution to all the needs of the city, one of the needs that must be met is the heat demand of all buildings. One possible way to meet these needs is through district heating. The aim of this report is to design and investigate the efficiency of a heat distribution network in the Southeast city district by determining its distribution losses and the requirements that heating distribution networks must fulfill. The method used to satisfy the purpose is to simulate the systems through a model in Python. The model produces key parameters such as distribution losses, pressure drop and temperature drop during high heat demand and low heat demand. The results of the report shows what a possible distribution network design could look like for two stages of construction. It is also shown that during low heat demand, the highest distribution losses were in the return pipe. During the high heat demand, the highest distribution losses were in the supply pipe. This is also the period of the greatest mass flow rate, temperature drop and pressure drop. The discussion addresses the correlation between these parameters as well as exploring how connecting an additional building stage impacts the performance of the system. The conclusions of this paper is that the designed distribution networks fulfill the necessary criteria for pressure, temperature and energy delivery with acceptable distribution losses. When a additional stage is connected to the system, distribution losses do not increase significantly, making the model suitable for future extensions of district heating networks.

The construction of the Southeast city district in Uppsala will start in 2025 with plans to be completed in 2050. When a new district is built, there is an opportunity to explore the best possible solution to all the needs of the city, one of the needs that must be met is the heat demand of all buildings. One possible way to meet these needs is through district heating. The aim of this report is to design and investigate the efficiency of a heat distribution network in the Southeast city district by determining its distribution losses and the requirements that heating distribution networks must fulfill. The method used to satisfy the purpose is to simulate the systems through a model in Python. The model produces key parameters such as distribution losses, pressure drop and temperature drop during high heat demand and low heat demand. The results of the report shows what a possible distribution network design could look like for two stages of construction. It is also shown that during low heat demand, the highest distribution losses were in the return pipe. During the high heat demand, the highest distribution losses were in the supply pipe. This is also the period of the greatest mass flow rate, temperature drop and pressure drop. The discussion addresses the correlation between these parameters as well as exploring how connecting an additional building stage impacts the performance of the system. The conclusions of this paper is that the designed distribution networks fulfill the necessary criteria for pressure, temperature and energy delivery with acceptable distribution losses. When a additional stage is connected to the system, distribution losses do not increase significantly, making the model suitable for future extensions of district heating networks.

The use of pit thermal energy storages (PTES) enables higher solar fraction in district heating networks by counteracting the mismatch between heat demand and production in solar district heating (SDH) installations. Capital costs linked to land areas with site-specific geological conditions are the deciding factors for PTES constructions. This study investigates non-technical and technical factors for the implementation of PTES in Swedish district heating networks. Having several SDH and PTES installations in operation the country of Denmark is used as a reference. This study, based on literature review, discusses the drivers and challenges for the use of PTES in district heating networks.

The use of pit thermal energy storages (PTES) enables higher solar fraction in district heating networks by counteracting the mismatch between heat demand and production in solar district heating (SDH) installations. Capital costs linked to land areas with site-specific geological conditions are the deciding factors for PTES constructions. This study investigates non-technical and technical factors for the implementation of PTES in Swedish district heating networks. Having several SDH and PTES installations in operation the country of Denmark is used as a reference. This study, based on literature review, discusses the drivers and challenges for the use of PTES in district heating networks.

The use of pit thermal energy storages (PTES) enables higher solar fraction in district heating networks by counteracting the mismatch between heat demand and production in solar district heating (SDH) installations. Capital costs linked to land areas with site-specific geological conditions are the deciding factors for PTES constructions. This study investigates non-technical and technical factors for the implementation of PTES in Swedish district heating networks. Having several SDH and PTES installations in operation the country of Denmark is used as a reference. This study, based on literature review, discusses the drivers and challenges for the use of PTES in district heating networks.

Fjärrvärmen utgör omkring hälften av all uppvärmning som sker i Sverige idag och har utöver det en viktig roll då den tar vara på mycket energi som annars hade gått till spillo. Att kunna vara ekonomiskt konkurrenskraftig gentemot andra uppvärmningsalternativ är en viktig del för fjärrvärmens fortsatta utveckling. Det finns flera alternativ och möjligheter att göra detta, ett av dem är att hålla nere driftkostnaderna. Det kan bland annat göras genom att minska tryckfallen i näten, som även kan ge en ökad expansionsmöjlighet. Idag används främst avstängningsventiler med reducerande genomlopp i näten, främst på grund av den billigare investeringen. Trots detta saknas en kunskap om hur dessa ventiler påverkar näten sett till tryckfall, drift- och investeringskostnader jämfört med ventiler med fullt genomlopp. För att undersöka detta har två metoder använts för att komplettera varandra och öka förståelsen för ventilerna. Den första metoden beräknade det generella fallet teoretiskt för att se vid vilka flöden som ventiler med fullt genomlopp är mer gynnsamma. Den andra metoden beräknade ett specifikt fall med simuleringar i ett verkligt nät med de olika ventilerna och beräkna vilken som är den mest ekonomiskt gynnsamma. Resultaten av det generella fallet visar att ventiler med fullt genomlopp blir mer gynnsamma när flödeshastigheten överstiger omkring 1 m/s, oavsett dimension, beräknat på under 30 år med ett elpris på 1,50 kr/kWh. Vid dimensionering av nät är det vanligt att använda 1,5 - 2,0 m/s, detta utgör ofta en liten del av nätets drifttid och är ofta lägre. Beräkning av det specifika fallet visade att ventiler med reducerande genomlopp är det ekonomiska alternativet då återbetalningstiden för ventiler med fullt genomlopp var över 600 år vid 1,50 kr/kWh. Utifrån detta kan slutsatsen dras att ventiler med fullt genomlopp inte bör ersätta reducerande genomlopp, utan att det i stället handlar om att identifiera de delar i nätet som utgör, eller kan komma att utgöra, e, District heating makes up about half of all heating that takes place in Sweden today and, in addition to that, has an important role as it makes use of a lot of energy that would otherwise have been wasted. Being able to be economically competitive against other heating alternatives is an important part of the continued development of district heating. There are several options to do this, one of which is to keep operating costs down. This can be done by reducing the pressure drops in the networks, which can also provide an increased possibility of expansion. Today, shut-off valves with reducing throughput are mainly used in networks, often because of the cheaper investment. Despite this, there is a lack of knowledge about how these valves affect the networks, which is attributed to pressure drop, operating and investment costs compared to valves with full flow. To investigate this, two methods have been used to complement each other and increase the understanding of the valves. In the first method, the general case is calculated theoretically to see at which flows valves with full flow are advantageous. The second method calculates a specific case with simulations in a real network with the different valves and calculates which one is the most economically advantageous. The results of the general case show that valves with full flow become more advantageous when the flow rate exceeds about 1 m/s, regardless of dimension, calculated over 30 years with an electricity price of SEK 1.50 /kWh. When dimensioning networks, 1.5 - 2.0 m/s is a common value, this often constitutes a small part of the network's operating time and is often lower. Calculation of the specific case showed that valves with reducing throughput are the economic alternative as the payback period for valves with full throughput was over 600 years at SEK 1.50/kWh. Based on this, the conclusion can be drawn that valves with full throughput should not replace reducing throughput, but that it is instead a

Fjärrvärmen utgör omkring hälften av all uppvärmning som sker i Sverige idag och har utöver det en viktig roll då den tar vara på mycket energi som annars hade gått till spillo. Att kunna vara ekonomiskt konkurrenskraftig gentemot andra uppvärmningsalternativ är en viktig del för fjärrvärmens fortsatta utveckling. Det finns flera alternativ och möjligheter att göra detta, ett av dem är att hålla nere driftkostnaderna. Det kan bland annat göras genom att minska tryckfallen i näten, som även kan ge en ökad expansionsmöjlighet. Idag används främst avstängningsventiler med reducerande genomlopp i näten, främst på grund av den billigare investeringen. Trots detta saknas en kunskap om hur dessa ventiler påverkar näten sett till tryckfall, drift- och investeringskostnader jämfört med ventiler med fullt genomlopp. För att undersöka detta har två metoder använts för att komplettera varandra och öka förståelsen för ventilerna. Den första metoden beräknade det generella fallet teoretiskt för att se vid vilka flöden som ventiler med fullt genomlopp är mer gynnsamma. Den andra metoden beräknade ett specifikt fall med simuleringar i ett verkligt nät med de olika ventilerna och beräkna vilken som är den mest ekonomiskt gynnsamma. Resultaten av det generella fallet visar att ventiler med fullt genomlopp blir mer gynnsamma när flödeshastigheten överstiger omkring 1 m/s, oavsett dimension, beräknat på under 30 år med ett elpris på 1,50 kr/kWh. Vid dimensionering av nät är det vanligt att använda 1,5 - 2,0 m/s, detta utgör ofta en liten del av nätets drifttid och är ofta lägre. Beräkning av det specifika fallet visade att ventiler med reducerande genomlopp är det ekonomiska alternativet då återbetalningstiden för ventiler med fullt genomlopp var över 600 år vid 1,50 kr/kWh. Utifrån detta kan slutsatsen dras att ventiler med fullt genomlopp inte bör ersätta reducerande genomlopp, utan att det i stället handlar om att identifiera de delar i nätet som utgör, eller kan komma att utgöra, e, District heating makes up about half of all heating that takes place in Sweden today and, in addition to that, has an important role as it makes use of a lot of energy that would otherwise have been wasted. Being able to be economically competitive against other heating alternatives is an important part of the continued development of district heating. There are several options to do this, one of which is to keep operating costs down. This can be done by reducing the pressure drops in the networks, which can also provide an increased possibility of expansion. Today, shut-off valves with reducing throughput are mainly used in networks, often because of the cheaper investment. Despite this, there is a lack of knowledge about how these valves affect the networks, which is attributed to pressure drop, operating and investment costs compared to valves with full flow. To investigate this, two methods have been used to complement each other and increase the understanding of the valves. In the first method, the general case is calculated theoretically to see at which flows valves with full flow are advantageous. The second method calculates a specific case with simulations in a real network with the different valves and calculates which one is the most economically advantageous. The results of the general case show that valves with full flow become more advantageous when the flow rate exceeds about 1 m/s, regardless of dimension, calculated over 30 years with an electricity price of SEK 1.50 /kWh. When dimensioning networks, 1.5 - 2.0 m/s is a common value, this often constitutes a small part of the network's operating time and is often lower. Calculation of the specific case showed that valves with reducing throughput are the economic alternative as the payback period for valves with full throughput was over 600 years at SEK 1.50/kWh. Based on this, the conclusion can be drawn that valves with full throughput should not replace reducing throughput, but that it is instead a

Society is facing a huge challenge in switching the energy sectors dependence on fossil fuels into an energy sector using mostly renewable energy sources. The switch towards using more sustainable energy sources is known as the energy transition. The goal of the energy transition is to lower the greenhouse gas (GHG) emissions emitted by the energy sector. Lowering the GHG emissions helps society limit the global warming caused by GHG [3]. 17.5 % of the global energy usage comes from the energy use in buildings [50]. It is thus very important that the energy use in buildings transitions towards using more sustainable energy sources. One of the renewable energy sources that is ought promising in the energy transition for energy use in buildings is geothermal energy [3]. Geothermal energy is energy that is captured in reservoirs of hot water in the earth’s crust. The hot water captured in the hot water pockets is pumped to the surface, to use it in spatial heating. The return pipe returns the cooled water to the geothermal well, where it can heat up again over a certain period of time [63] [23]. In some cases, geothermal energy is applied using a district heating network. A district heating network is an example of a system that provides heating and/or cooling capacities to a group of buildings [65]. A district heating network is a network of pipelines that transport the hot water from the geothermal well to the buildings in the district. A geothermal well in combination with a district heating network is developed in Delft [27]. The district heating network will deliver energy to the TU Delft campus, two neighborhoods in Delft and industry at the Schieweg in Delft [28]. Besides the district heating network in Delft, it is expected that district heating networks will be applied more often to accelerate the energy transition. Yun-Chao and Chen (2012) concluded that most optimization techniques optimize the whole system with its components. Less optimiz, Complex Systems Engineering and Management (CoSEM)

The Dutch government is committed to transitioning to a low-carbon economy. District heating networks are considered essential for achieving this transition. This research aims to compare two different methods of involving citizens in decision-making and development related to district heating networks. The novel Participatory Value Evaluation (PVE) method is compared to a general survey to explore differences in the results of these two. The research approach encompasses multiple components, including 12 stakeholder interviews, the design and use of a Participatory Value Evaluation (PVE) and survey and subsequent analysis. The survey and PVE were even and randomly distributed across 2700 citizens of the neighbourhood Blijdorp in Rotterdam. This led to 138 completed PVE’s or surveys. As a last step the results of the two different consultations were analysed in terms of reaching the stakeholders goals. The research findings indicate that a Participatory Value Evaluation and survey have different results in incorporating the goals of the involved stakeholders. The PVE was able to create more detailed input for the stakeholders and was better in creating understanding of the complexity of the problems the stakeholders are facing. However, it is important to acknowledge that respondents in the PVE took longer to complete the evaluation and the PVE was rated more challenging than the survey. As a result, the response rate for the PVE was only half as much as the survey. This research contributes to the field of research into public participation in multiple ways. Firstly, the PVE has been applied in a new context. It has been shown that a PVE can be utilised to address the challenges of engaging citizens in the establishment of heat networks. Secondly, most studies on a PVE as a participatory method lack comparative research. This study demonstrates that a PVE and survey have distinct advantages and disadvantages. The identified advantages and disadvantages have been co, Civil Engineering | Construction Management and Engineering

This study concerns the development of a data-based compact model for the prediction of the fluid temperature evolution in district heating (DH) pipeline networks. This so-called “reduced-order model” (ROM) is obtained from reduction of the conservation law for energy for each pipe segment to a semi-analytical input–output relation between the pipe outlet temperature and the pipe inlet and ground temperatures that can be identified from training data. The ROM basically is valid for generic pipe configurations involving 3D unsteady heat transfer and 3D steady flow as long as heat-transfer mechanisms are linearly dependent on the temperature field. Moreover, the training data can be generated by physics-based computational “full-order” models (FOMs) yet also by (calibration) experiments or field measurements. Performance tests using computational training data for a single-pipe configuration demonstrate that the ROM (i) can be successfully identified and (ii) can accurately describe the response of the outlet temperature to arbitrary input profiles for inlet and ground temperatures. Application of the ROM to two case studies, i.e. fast simulation of a small DH network and design of a controller for user-defined temperature regulation of a DH system, demonstrate its predictive ability and efficiency also for realistic systems. Dedicated cost analyses further reveal that the ROM may significantly reduce the computational costs compared to FOMs by (up to) orders of magnitude for higher-dimensional pipe configurations. These findings advance the proposed ROM as a robust and efficient simulation tool for practical DH systems with a far greater predictive ability than existing compact models.

In the context of district heating networks we consider a model for the distribution of energy through water (for heating or cooling) from a central power station to the consumers. We prove the well posedness of the system, by using the Banach Fixed Point Theorem together with stability estimates for reduced systems. Eventually we consider optimal control problems motivated by applications and we provide the existence of optimal controls in special situations.

District heating systems (DHSs) have the potential to play a big part in the energy transition. The efficient operation of DHSs is therefore also an important subject of study. The operation of DHSs where combined heat and power (CHP) plants are used are particularly interesting, because CHPs can operate with high efficiency. In this work, the operational optimization of DHSs with CHP plants is considered. Determining the optimal heat and electricity production for CHPs for multiple time steps into the future is a complex problem. Because of the heat storage capabilities in the network many solutions are feasible, but determining which solutions are infeasible because of constraint violations in the DHS involves computing time delays that depend on complex network dynamics. In this work, the possibility of using an input convex neural network (ICNN) to learn the network dynamics of a DHS is explored. ICNNs have limitations on their learning capabilities, but theoretically allow for easier optimization. Experiments on the learning capabilities of ICNNs reveal that caution should be used when they are used to learn non-convex constraints, as the accuracy of the ICNN highly depends on how non-convex the function is. Experiments on the feasible space of supply temperatures to a small district heating network (DHN) reveal that although the network does not provide the same flexibility as heat storage tanks, still some flexibility in the operation can be found. This is due to the fact that water with a higher supply temperature is consumed by consumers at a slower pace and this increases the time delay between production and consumption. Supply temperatures that follow can then be lowered if the increased time delay causes this water to arrive when the heat demands are lower. In the experiments it was found that this flexibility in operation translates to non-convex areas in the feasible space. When this space would be learned by an ICNN, this s, Computer Science

This work compares the economic viability of active and passive condensation in a medium-scale biomass combustion plant considering the variability of the return temperature and heat demand over the year. A typical District Heating plant with a total installed power of 9.5 MWth is considered. The economic feasibility is evaluated by means of the Net Present Value (NPV), Discounted Payback Period (DPP), and the Modified Internal Rate of Return (MIRR). Compared to passive condensation, the NPV of an active condensation plant is 66% higher and reduces the primary energy consumption by more than 50%. However, a higher initial investment and a higher DPP are calculated. Assuming constant return temperature and average heat demand over the year lead to an overestimation of the NPV by more than 110% for an active condensation plant and by more than 160% for a passive condensation plant. The NPV, DPP and MIRR are strongly impacted by a variation of the return temperature of the network., SCOPUS: ar.j, info:eu-repo/semantics/published

District heating systems (DHSs) have the potential to play a big part in the energy transition. The efficient operation of DHSs is therefore also an important subject of study. The operation of DHSs where combined heat and power (CHP) plants are used are particularly interesting, because CHPs can operate with high efficiency. In this work, the operational optimization of DHSs with CHP plants is considered. Determining the optimal heat and electricity production for CHPs for multiple time steps into the future is a complex problem. Because of the heat storage capabilities in the network many solutions are feasible, but determining which solutions are infeasible because of constraint violations in the DHS involves computing time delays that depend on complex network dynamics. In this work, the possibility of using an input convex neural network (ICNN) to learn the network dynamics of a DHS is explored. ICNNs have limitations on their learning capabilities, but theoretically allow for easier optimization. Experiments on the learning capabilities of ICNNs reveal that caution should be used when they are used to learn non-convex constraints, as the accuracy of the ICNN highly depends on how non-convex the function is. Experiments on the feasible space of supply temperatures to a small district heating network (DHN) reveal that although the network does not provide the same flexibility as heat storage tanks, still some flexibility in the operation can be found. This is due to the fact that water with a higher supply temperature is consumed by consumers at a slower pace and this increases the time delay between production and consumption. Supply temperatures that follow can then be lowered if the increased time delay causes this water to arrive when the heat demands are lower. In the experiments it was found that this flexibility in operation translates to non-convex areas in the feasible space. When this space would be learned by an ICNN, this s, Computer Science

District heating networks have become widespread due to their ability to distribute thermal energy efficiently, which leads to reduced carbon emissions and improved air quality. Additional benefits can derive from novel demand side management strategies, which can efficiently balance demand and supply. However, their implementation requires detailed knowledge of heating network characteristics, which vary remarkably depending on urban layout and system amplitude. Moreover, extensive data about the energy distribution and thermal capacity of different areas are seldom available. For this purpose, the present work proposes a novel procedure to develop a fast scale-free model of large-scale district heating networks for system optimization and control. Each network community is represented and modeled as an aggregated region. Its physics-based model is identified starting from a limited amount of data available at the main substations and includes heat capacity and heat loss coefficients. The procedure is demonstrated and validated on the network of Va center dot steras, Sweden, showing results that are in agreement with data from the literature. Thus, the model is well suited for real-time optimization and predictive control. In particular, the possibility to easily estimate the heat storage potential of network communities allows demand side management solutions to be applied in several conditions.

Of the global energy demand, 20% can be allocated to residential energy demand. Most of this energy is produced by fossil fuels, which raises the importance of energy production in a more sustainable way. In order to do this on the level of residential heating applications, the Dutch government aims to make its residential neighborhoods natural gas-free. An often considered solution is making residential areas all-electric. However, when considering the heating of these households based on electricity, high peaks may occur in the electricity grid due to simultaneous heating at times of high demand. This could cause problems regarding the capacity of the electricity grid. Subsequently, the generation of electricity is nowadays associated with relatively high CO2 emissions, raising the awareness for alternative methods of heating. One of these methods is district heating coupled to (more) sustainable energy sources. A problem occurring with this combination is a possible discrepancy between the supply and demand of energy. Therefore, it could be beneficial to implement thermal energy storage in district heating. This research assesses the feasibility of different configurations of thermal energy storage integrated into district heating. For this research, a case study is conducted in which district heating for a residential area coupled with thermal energy storage is modeled. The model is based on the thermodynamic equilibrium of the network and is able to compute the required characteristics and key performance indicators of the district heating network. For the case study, multiple scenarios have been created which assess different distribution characteristics and heat sources. For reference, an all-electric scenario has been designed as well. The results of the case study show that the implementation of thermal energy storage in district heating is able to lower peak loads on the heat source by two-thirds. This implementation goes paired with an increase in leveliz, Mechanical Engineering

There are several different methods to solve the steady-state flow problem of district heating networks and gas networks. In this thesis, the nodal method, the loop method, and the loop-node method are compared. This is done in order to determine for what type of network, with specific characteristics, which of these methods is preferred. In this comparison, the focus is on computer storage, sensibility to starting values, convergence properties, and computational time., Applied Mathematics

This paper presents a thermo-economic optimisation of an electrified district heating network consisting of wind power plant, gas-fired combined heat and power plant and heat pumps. The load flow problem of the resulting multi-energy system is formulated by considering all physical and operating parameters in both of the electricity and heat distribution networks. First, energy and exergy analyses are applied to identify and isolate lossy branches of a meshed heating network. This is followed by the optimal placement of heat pumps. Finally, supply and return temperatures are optimised. Particle swarm optimisation technique is implemented in order to find the best place of heat pumps, their economical dispatch and optimal temperature profile of the district heating network. Results show that up to 59.12% of the distribution heat loss and 9.37% of the operating cost can be saved by following a step-by-step methodology discussed in this paper., QC 20210611

The purpose of this report is to get an overview of the CO2 reduction possibilities when adopting different renewable energy source, when the case studied building sustains a district heating network connection and when not, and how the renewable energy source flexibilities (Solar and Wind) differ depending on region. The method regards a ETC house that falls into the climate positive category and assesses the reduction when comparing CO2 emissions form the energy demand. The result for the flexibilities is then compared to the BBR demand. The result shows a difference of around 10% in production for the flexibilities when comparing the northern and middle region with the southern. And a decrease between 19-36% gCO2. Comparing a scenario with and without a connection to the district heating network showed that when the ground source heat pump offsets the energy demand, CO2, and cost reductions (6 and 4% respectively) can be seen. With an average installation cost, the payback period for the ground source heat pump can be estimated to be around 4 year. In conclusion the thesis project shows that the climate is a ruling factor when assessing energy questions for the residential sector. It also shows the difference in CO2 and cost that comes with it can be reduced and help mitigated the sectors effects on the environment. This in turn shows that the overall reduction of CO2 for the case studied building follows the demands and goals set by the European commission and gives motivation to expand the construction as cost is also reduced.

The purpose of this report is to get an overview of the CO2 reduction possibilities when adopting different renewable energy source, when the case studied building sustains a district heating network connection and when not, and how the renewable energy source flexibilities (Solar and Wind) differ depending on region. The method regards a ETC house that falls into the climate positive category and assesses the reduction when comparing CO2 emissions form the energy demand. The result for the flexibilities is then compared to the BBR demand. The result shows a difference of around 10% in production for the flexibilities when comparing the northern and middle region with the southern. And a decrease between 19-36% gCO2. Comparing a scenario with and without a connection to the district heating network showed that when the ground source heat pump offsets the energy demand, CO2, and cost reductions (6 and 4% respectively) can be seen. With an average installation cost, the payback period for the ground source heat pump can be estimated to be around 4 year. In conclusion the thesis project shows that the climate is a ruling factor when assessing energy questions for the residential sector. It also shows the difference in CO2 and cost that comes with it can be reduced and help mitigated the sectors effects on the environment. This in turn shows that the overall reduction of CO2 for the case studied building follows the demands and goals set by the European commission and gives motivation to expand the construction as cost is also reduced.

There are several different methods to solve the steady-state flow problem of district heating networks and gas networks. In this thesis, the nodal method, the loop method, and the loop-node method are compared. This is done in order to determine for what type of network, with specific characteristics, which of these methods is preferred. In this comparison, the focus is on computer storage, sensibility to starting values, convergence properties, and computational time., Applied Mathematics

Of the global energy demand, 20% can be allocated to residential energy demand. Most of this energy is produced by fossil fuels, which raises the importance of energy production in a more sustainable way. In order to do this on the level of residential heating applications, the Dutch government aims to make its residential neighborhoods natural gas-free. An often considered solution is making residential areas all-electric. However, when considering the heating of these households based on electricity, high peaks may occur in the electricity grid due to simultaneous heating at times of high demand. This could cause problems regarding the capacity of the electricity grid. Subsequently, the generation of electricity is nowadays associated with relatively high CO2 emissions, raising the awareness for alternative methods of heating. One of these methods is district heating coupled to (more) sustainable energy sources. A problem occurring with this combination is a possible discrepancy between the supply and demand of energy. Therefore, it could be beneficial to implement thermal energy storage in district heating. This research assesses the feasibility of different configurations of thermal energy storage integrated into district heating. For this research, a case study is conducted in which district heating for a residential area coupled with thermal energy storage is modeled. The model is based on the thermodynamic equilibrium of the network and is able to compute the required characteristics and key performance indicators of the district heating network. For the case study, multiple scenarios have been created which assess different distribution characteristics and heat sources. For reference, an all-electric scenario has been designed as well. The results of the case study show that the implementation of thermal energy storage in district heating is able to lower peak loads on the heat source by two-thirds. This implementation goes paired with an increase in leveliz, Mechanical Engineering

Digitalization and smart control of district heating networks are emerging as key features to make these systems flexible and optimal. However, since effective and scalable methods for large-scale systems are currently unavailable, the implementation of smart controllers can be challenging and time-consuming. This is addressed herein by proposing a novel approach to include the thermal capacity of the connected buildings in the optimal control of large-scale heating networks. A reduced-order model of the aggregated communities supplied by a large-scale network is used to define their State of Charge, which is exploited to store or retrieve energy when convenient, while maintaining indoor comfort. This concept is included in a Model Predictive Controller that optimizes power plant management and heat distribution. The results show that the controller successfully shaves heat supply peaks to different regions up to 16% and reduces the difference between distribution and soil temperature up to 20%. At the same time, the return temperature is kept close to the set-point of 35 degrees C, which is lower than the historical operation and further reduces distribution heat losses. The procedure can be easily replicated to optimize systems of different sizes and to support their transition to efficient, smart district heating networks.

I Sverige är fjärrvärme den vanligaste uppvärmningsformen. Vatten värms upp i en fjärrvärmeanläggning och distribueras genom nedgrävda rör i marken, också kallat fjärrvärmenätet. En tillförlitlig energimodell anses vara ett bra och viktigt hjälpmedel för analyser av värmeförluster som uppstår i ett fjärrvärmenät vid distribueringen av det heta vattnet. Sandviken Energis styrning av framledningstemperaturen sker idag utifrån en inställd styrkurva som tar hänsyn till vad det är för utetemperatur. Det var av intresse för studien att jämföra denna styrning med en simulerad framledningstemperatur och identifiera övertemperaturer i Sandviken Energis fjärrvärmenät i Sandviken. Detta gjordes utifrån att undersöka hur olika faktorer påverkade värmebehovet. De påverkande faktorer som studerats i detta examensarbete var följande: utetemperatur, månad, tid på dygnet och vindhastighet. Mätdata gällande valda påverkande faktorer hämtades för perioderna 2015 till och med 2019, analyserades och indelades för att se deras påverkan på värmelasten. Utifrån indelningen av faktorerna utvanns ekvationer från deras effektkurvors trendlinjer. Ekvationerna användes för att skapa en simuleringsmatris för styrningen. En egenskapad masterekvation simulerade den ideala styrningen utifrån simuleringsmatrisen och de krav på påverkande faktorer som ställs av ett exempel-år. Den ideala styrningen beräknades om till en ideal framledningstemperatur och jämfördes därefter med den verkliga framledningstemperaturen. Tillsammans med en värmeförlustsimulering i NetSim, som resulterade i vad sparad energi per grad är värd, kunde besparingspotentialen beräknas. Resultatet visar på att en besparingspotential på 261 MWh är möjlig att uppnå vid en sänkning av framledningstemperaturen för att utesluta övertemperaturer i fjärrvärmenätet, vilket är en minskning med ca 1,8 % jämfört med det verkliga året. Detta skulle motsvara en besparing på ca 70 000 SEK genom en förändring av styrningen. En minskad framlednings, In Sweden district heating is the most common form of heating. Water is heated in a district heating plant and distributed through buried pipelines in the ground, also called the district heating network. A reliable energy model is considered to be a good and important tool for analysis of heat losses that occur in a district heating network when the hot water is distributed. Sandviken Energi’s control of the supply temperature is based today on a set control curve that takes into account what the outdoor temperature is. It was of interest to this study to compare this control with a simulated supply temperature and identify overtemperatures in Sandviken Energi’s district heating network in Sandviken. This was done on the basis of examining how different factors affected the heat demand. The influencing factors studied in the thesis were the following: outdoor temperature, month, time of day and wind speed. Measurement data on selected influencing factors were collected for the periods 2015 through 2019, analyzed and subdivided to see their effect on the heat load. From the subdivision of the factors, equations were extracted from the trend lines of their effect curves. The equations were used to create a simulations matrix for the control. A custom master equation simulated the ideal control based on the simulation matrix and the demands on influencing factors set by an example year. The ideal control was recalculated to an ideal supply temperature and then compared with the actual supply temperature. Together with a heat loss simulation in NetSim, which resulted in what energy saved per degree is worth, the savings potential could be calculated. The result shows that a saving potential of 261 MWh is possible to achieve by lowering the supply temperature to exclude excess temperatures in the district heating network, which is a decrease of about 1.8 % compared to the real year. This would correspond to a savings of about 70 000 SEK through a change in control. A re

I Sverige är fjärrvärme den vanligaste uppvärmningsformen. Vatten värms upp i en fjärrvärmeanläggning och distribueras genom nedgrävda rör i marken, också kallat fjärrvärmenätet. En tillförlitlig energimodell anses vara ett bra och viktigt hjälpmedel för analyser av värmeförluster som uppstår i ett fjärrvärmenät vid distribueringen av det heta vattnet. Sandviken Energis styrning av framledningstemperaturen sker idag utifrån en inställd styrkurva som tar hänsyn till vad det är för utetemperatur. Det var av intresse för studien att jämföra denna styrning med en simulerad framledningstemperatur och identifiera övertemperaturer i Sandviken Energis fjärrvärmenät i Sandviken. Detta gjordes utifrån att undersöka hur olika faktorer påverkade värmebehovet. De påverkande faktorer som studerats i detta examensarbete var följande: utetemperatur, månad, tid på dygnet och vindhastighet. Mätdata gällande valda påverkande faktorer hämtades för perioderna 2015 till och med 2019, analyserades och indelades för att se deras påverkan på värmelasten. Utifrån indelningen av faktorerna utvanns ekvationer från deras effektkurvors trendlinjer. Ekvationerna användes för att skapa en simuleringsmatris för styrningen. En egenskapad masterekvation simulerade den ideala styrningen utifrån simuleringsmatrisen och de krav på påverkande faktorer som ställs av ett exempel-år. Den ideala styrningen beräknades om till en ideal framledningstemperatur och jämfördes därefter med den verkliga framledningstemperaturen. Tillsammans med en värmeförlustsimulering i NetSim, som resulterade i vad sparad energi per grad är värd, kunde besparingspotentialen beräknas. Resultatet visar på att en besparingspotential på 261 MWh är möjlig att uppnå vid en sänkning av framledningstemperaturen för att utesluta övertemperaturer i fjärrvärmenätet, vilket är en minskning med ca 1,8 % jämfört med det verkliga året. Detta skulle motsvara en besparing på ca 70 000 SEK genom en förändring av styrningen. En minskad framlednings, In Sweden district heating is the most common form of heating. Water is heated in a district heating plant and distributed through buried pipelines in the ground, also called the district heating network. A reliable energy model is considered to be a good and important tool for analysis of heat losses that occur in a district heating network when the hot water is distributed. Sandviken Energi’s control of the supply temperature is based today on a set control curve that takes into account what the outdoor temperature is. It was of interest to this study to compare this control with a simulated supply temperature and identify overtemperatures in Sandviken Energi’s district heating network in Sandviken. This was done on the basis of examining how different factors affected the heat demand. The influencing factors studied in the thesis were the following: outdoor temperature, month, time of day and wind speed. Measurement data on selected influencing factors were collected for the periods 2015 through 2019, analyzed and subdivided to see their effect on the heat load. From the subdivision of the factors, equations were extracted from the trend lines of their effect curves. The equations were used to create a simulations matrix for the control. A custom master equation simulated the ideal control based on the simulation matrix and the demands on influencing factors set by an example year. The ideal control was recalculated to an ideal supply temperature and then compared with the actual supply temperature. Together with a heat loss simulation in NetSim, which resulted in what energy saved per degree is worth, the savings potential could be calculated. The result shows that a saving potential of 261 MWh is possible to achieve by lowering the supply temperature to exclude excess temperatures in the district heating network, which is a decrease of about 1.8 % compared to the real year. This would correspond to a savings of about 70 000 SEK through a change in control. A re

District heating systems (DHS) are considered the best alternative to individual heat boilers as they have higher efficiency and enable the use of sustainable heat sources, like geothermal heat sources or waste heat from industry. Currently, most DHSs are operated by choosing a temperature once every day depending on the weather. This setting is chosen such that peak demand can be satisfied. However, when demand is lower, the supply temperature will be higher than necessary and heat will be wasted. In addition to this, heat production costs can be dynamic over time, which allows more cost-efficient heat production scheduling. By choosing a dynamic temperature over the day losses and operating costs can be reduced. However, determining these dynamic temperatures is not easy, as there are several factors that need to be taken into account to ensure that demand can always be fulfilled. In this research, the use of metaheuristics is explored for finding supply temperatures. Optimisation of DHS operations results in up to 5% savings with respect to typical heating curve operations. The second contribution is a method to determine a theoretical lower bound on the operating costs of a DHS, as this was not yet found in literature.

This research has compared three different market mechanisms in a quantitative way. The influences of these market mechanisms on the heating system were investigated for CO2 emissions, consumer price and producer surplus. In addition, the influences of investment decisions and price and consumption growth scenarios were tested. The research showed that the end-to-end market mechanism is the least uncertain in the future and is only influenced by consumption growth. In addition, the construction of a large source of residual heat can moderate this effect. The wholesale market is strongly influenced by price scenarios. This effect can be moderated by the construction of the pipeline through the Midden, which connects two different heating systems. Finally, there is the single buyer market. This is influenced by both scenario variables, while no investment decisions affect it. Further research must be done into the latter market mechanism. And the models need to be extended to more specific markets because this research has used archetypes. Keywords: District heating network, Market mechanism, Single-buyer, Complex Systems Engineering and Management (CoSEM)

In order to reduce CO2 emission, district heat networks and carbon-neutral heat energy production are being developed in the Netherlands. This resulted in an increasing amount of district heating systems (DHS) in the horticulture areas. A DHS in a region called the ”B3-Hoek” connects multiple producers with horticulture companies in a single-buyer market model with long term bilateral contracts. This market model has some undesirable aspects that contribute to the willingness of introducing a short term heat market model in the system. However, such a short term market is still prone to market failures, if producers have considerable market power. The aim of this research is to investigate how a short term market can be designed for a DHS in the Netherlands, how producers and large consumers behave on a short term market and how this affects the performance of the market. An interactive simulation of a short term heat market was created, based on the DHS in the B3-Hoek to investigate this. The findings in this research give a conceptual model of the new market design and it showt that in a short term heat market prices will converge to marginal cost levels when market conditions are not tight. There is a balance of market power between the producers and the horticulture companies collectively. The results of short term market will not be comparable to the case of a perfectly competitive market due to Cournot competitive behaviour, but they can still be considered desirable for both horticulture companies and producers., Complex Systems Engineering and Management (CoSEM)

District heating systems (DHS) are considered the best alternative to individual heat boilers as they have higher efficiency and enable the use of sustainable heat sources, like geothermal heat sources or waste heat from industry. Currently, most DHSs are operated by choosing a temperature once every day depending on the weather. This setting is chosen such that peak demand can be satisfied. However, when demand is lower, the supply temperature will be higher than necessary and heat will be wasted. In addition to this, heat production costs can be dynamic over time, which allows more cost-efficient heat production scheduling. By choosing a dynamic temperature over the day losses and operating costs can be reduced. However, determining these dynamic temperatures is not easy, as there are several factors that need to be taken into account to ensure that demand can always be fulfilled. In this research, the use of metaheuristics is explored for finding supply temperatures. Optimisation of DHS operations results in up to 5% savings with respect to typical heating curve operations. The second contribution is a method to determine a theoretical lower bound on the operating costs of a DHS, as this was not yet found in literature.

This research has compared three different market mechanisms in a quantitative way. The influences of these market mechanisms on the heating system were investigated for CO2 emissions, consumer price and producer surplus. In addition, the influences of investment decisions and price and consumption growth scenarios were tested. The research showed that the end-to-end market mechanism is the least uncertain in the future and is only influenced by consumption growth. In addition, the construction of a large source of residual heat can moderate this effect. The wholesale market is strongly influenced by price scenarios. This effect can be moderated by the construction of the pipeline through the Midden, which connects two different heating systems. Finally, there is the single buyer market. This is influenced by both scenario variables, while no investment decisions affect it. Further research must be done into the latter market mechanism. And the models need to be extended to more specific markets because this research has used archetypes. Keywords: District heating network, Market mechanism, Single-buyer, Complex Systems Engineering and Management (CoSEM)

In order to reduce CO2 emission, district heat networks and carbon-neutral heat energy production are being developed in the Netherlands. This resulted in an increasing amount of district heating systems (DHS) in the horticulture areas. A DHS in a region called the ”B3-Hoek” connects multiple producers with horticulture companies in a single-buyer market model with long term bilateral contracts. This market model has some undesirable aspects that contribute to the willingness of introducing a short term heat market model in the system. However, such a short term market is still prone to market failures, if producers have considerable market power. The aim of this research is to investigate how a short term market can be designed for a DHS in the Netherlands, how producers and large consumers behave on a short term market and how this affects the performance of the market. An interactive simulation of a short term heat market was created, based on the DHS in the B3-Hoek to investigate this. The findings in this research give a conceptual model of the new market design and it showt that in a short term heat market prices will converge to marginal cost levels when market conditions are not tight. There is a balance of market power between the producers and the horticulture companies collectively. The results of short term market will not be comparable to the case of a perfectly competitive market due to Cournot competitive behaviour, but they can still be considered desirable for both horticulture companies and producers., Complex Systems Engineering and Management (CoSEM)

Integration of electricity and heat distribution networks offers extra flexibility to system operation and improves energy efficiency. The energy hub (EH) plays an important role in energy production, conversion and storage in such coupled infrastructures. This paper provides a new outlook and thorough mathematical tool for studying the integrated energy system from a deregulated market perspective. A mathematic program with equilibrium constraints (MPEC) model is proposed to study the strategic behaviors of a profit-driven energy hub in the electricity market and heating market under the background of energy system integration. In the upper level, the EH submits bids of prices and quantities to a distribution power market and a heating market; in the lower level, the two markets are cleared and energy contracts between the EH and two energy markets are determined. Network constraints of physical systems are explicitly represented by an optimal power flow problem and an optimal thermal flow problem. The proposed MPEC formulation is approximated by a mixed-integer linear program via performing integer disjunctions on the complementarity and slackness conditions and binary expansion technique on the bilinear production terms. Case studies demonstrate the effectiveness of the proposed model and method.

Despite their obvious benefit in terms of energy efficiency and their potential benefit on pollutant emissions, Flue Gas Condensers (FGCs) are still not widely spread in biomass combustion plants. Although their costs have significantly decreased during the last decade, the economic viability of FGC retrofits is not straightforward and their return on investments is mainly dependent on the temperature of the available heat sink and the moisture content of the fuel. Based on a new techno-economic model of a FGC validated with recent industrial data, this paper presents a methodology to assess the economic viability of an FGC retrofitting in a medium-scale biomass combustion plant. The proposed methodology is applied to the case of a typical District Heating plant for which real data was collected. For the first time, the usual assumptions of constant process data generally used are challenged by considering the variability of the return temperature and heat demand over the year. Furthermore, a new concept of optimal configurations in terms of energy savings is introduced in this paper and compared to a strictly economic optimum. The economic feasibility is mainly evaluated by means of the Net Present Value (NPV), Discounted Payback Period (DPP), and the Modified Internal Rate of Return (MIRR). As expected, results show that the higher the humidity level and the lower the return temperature, the higher the economic profitability of a project. The NPV is, however, increased when considering variable inputs: Even with an average return temperature of 60 °C, a mixed operation of the FGC as a condenser and an economizer along the year is predicted, which results in an increased profitability assessment. Considering a constant return temperature over the year can lead to a 20% underestimation of the project NPV. An alternative averaging method is proposed, where two distinct temperature zones are considered: above and below the flue gas dew point. The discrepancy with a de, SCOPUS: ar.j, info:eu-repo/semantics/published

This paper proposes an economic dispatch method for an integrated heat and electricity system with respect to network constraints. Network constraints are usually nonlinear and can cause severe difficulties for optimization solvers. Particularly, in a heating network, the mass flow mixing at each node and the pressure and temperature drop along each pipe involve both hydraulic and thermal processes, which can cause high nonlinearity that has not been properly modeled. This paper will firstly model the power and heat network constraints by using a nonlinear model, which is accurate but hard to solve. Then, simplification and convexification will be employed to reform the nonlinear constraints to linear and conic ones. Consequently, the entire economic dispatch problem will be modeled as a mixed integer conic programming problem. Because the proposed model allows for the changes of the mass flow rate and direction, an optimal mass flow profile can be achieved along with the solution of the economic dispatch. Case studies on an integrated district heating and power system with a portfolio of power and heat sources show that the proposed economic dispatch model can handle the complexity of the network constraints and make optimal dispatch plans for multi-energy systems.

Growing shares of intermittent renewable energy sources in power systems lead to temporal imbalances between electricity supply and demand. Technologies which help to balance the electric grid such as energy storages, demand response or flexible coge-neration concepts are therefore gaining on importance. However, the investigation of these potentials from a system perspective requires a simulation approach that takes into account the interactions between supply and demand side as well as power system stability. While most prior studies utilize either linear optimization models to investigate storage options on a system level, or nonlinear simulation models for power system analysis, the present work utilizes a combination of both approaches.

Among other solutions, the integration of solar energy in district heating networks can contribute significantly to the increase of the renewable energy fraction in an urban area. This article describes the methodology developed in the framework of IEA Task 52 to help stakeholders during early phases of new or refurbishments projects. This methodology integrates a tool which is capable to assess the main solar indicators of the project with only two inputs: the solar installation area and the building heated area. The tool outputs are compared to the measured values of a Swedish case study.

Among other solutions, the integration of solar energy in district heating networks can contribute significantly to the increase of the renewable energy fraction in an urban area. This article describes the methodology developed in the framework of IEA Task 52 to help stakeholders during early phases of new or refurbishments projects. This methodology integrates a tool which is capable to assess the main solar indicators of the project with only two inputs: the solar installation area and the building heated area. The tool outputs are compared to the measured values of a Swedish case study.

Among other solutions, the integration of solar energy in district heating networks can contribute significantly to the increase of the renewable energy fraction in an urban area. This article describes the methodology developed in the framework of IEA Task 52 to help stakeholders during early phases of new or refurbishments projects. This methodology integrates a tool which is capable to assess the main solar indicators of the project with only two inputs: the solar installation area and the building heated area. The tool outputs are compared to the measured values of a Swedish case study.

Among other solutions, the integration of solar energy in district heating networks can contribute significantly to the increase of the renewable energy fraction in an urban area. This article describes the methodology developed in the framework of IEA Task 52 to help stakeholders during early phases of new or refurbishments projects. This methodology integrates a tool which is capable to assess the main solar indicators of the project with only two inputs: the solar installation area and the building heated area. The tool outputs are compared to the measured values of a Swedish case study.

This paper presents system simulation and parametric study of the demonstration system of decentralized cooling in district heating network. The monitoring results obtained from the demonstration were calibrated and used for parametric studies in order to find improved system design and control. This study concentrates on system simulation studies that aim to: reduce the electricity consumption, to improve the thermal COP's and capacity if possible; and to study how the system would perform with different boundary conditions such as climate and load. The internal pumps inside the thermally driven chiller (TDC) have been removed in the new version TDC and implemented in this study to increase the electrical COP. Results show that replacement of the fourth with the fifth generation TDC increases the system electrical COP from 2.64 to 5.27. The results obtained from parametric studies show that the electrical and thermal COP's, with new realistic boundary conditions, increased from 2.74 to 5.53 and 0.48 to 0.52, respectively for the 4th generation TDC and from 5.01 to 7.46 and 0.33 to 0.43, respectively for the 5th generation TDC. Additionally the delivered cold increased from 2320 to 8670 and 2080 to 7740. kWh for the 4th and 5th generation TDC's, respectively., QC 20110408

This article presents the monitoring results of a thermally driven chiller (TDC) driven by district heat from a network supplied by a centralised combined heat and power (CHP) fired with municipal waste. The main objective of this article is to analyse the monitoring results obtained from the demonstration and calibrate a system model that is later used for parametric studies in order to find improved system design and control. The calibration of the system model was made in three stages and all the energy performance figures were within 4% of the measured values. Results show that the TDC system is capable of providing maximum thermal and electrical COP's of 0.50 and 4.6 respectively during the hottest period. For the complete monitoring period during the summer of 2008, the figures were 0.41 and 2.1. The lower figures were due to continuous pump operation inside the TDC even during periods of no cold production and a period when no cold was produced. However the internal pumps inside the TDC have been removed in the new version TDC to increase the electrical COP. System simulation and parametric studies will be employed to further determine how the electrical COP can be improved., QC 20110408