Thermoeconomics as a tool for the design and analysis of energy savings initiatives in buildings connected to district heating networks

District Heating (DH) is a rational way to supply heat to buildings in urban areas. This is expected to play an important role in future energy scenarios, mainly because of the possibility to recover waste heat and to integrate renewable energy sources. Even if DH is a well known technology, there are open problems to face. Some of these problems are related to tendencies to reduce design temperatures, the improvement of control strategies, connection of new users to existing networks, implementation of energy savings initiatives and the access of multiple heat producers to the same network. This paper aims to show that exergy is an appropriate quantity for the analysis of DH systems and thermoeconomics can be profitably used to improve their design and operation. Three possible applications of thermoeconomic theories are presented: variation of supply temperature along the heating season, opportunities to connect new users, effects of energy savings initiatives in buildings connected with the network

Thermoeconomic approach for the analysis of low temperature district heating systems

In this paper a thermoeconomic analysis of district heating systems is performed. The analysis aims at comparing possible options to supply heat to the users, using low temperature networks. Thermoeconomic analysis consists a powerful tool to perform such analysis as it allows one to evaluate the possible options in terms of primary energy cost or economic costs. In the first case, the use of exergy as the quantity that is transported along the network makes it possible to properly consider the various qualities of energy that are used to supply heat to the network and to distribute it to the users. In the case of economic cost, the various cost contributions are considered: investment cost, cost of heat supplied to the network, pumping cost. A different cost can be calculated for the various users depending on their position and characteristics of the heating devices. This is a useful information in order to compare possible options for supply them hea

EXERGETIC AND THERMOECONOMIC APPROACH FOR OPTIMAL PLANNING OF DISTRICT ENERGY SYSTEMS

A sustainable urban energy planning for achieving the EU 2020 and 2050 energy goals requires adopting a systemic approach based on reducing end-user energy requirements, recycling energy that otherwise would be wasted and replacing fossil fuels by renewable. District Heating and District Cooling play a key role in such a concept. From the sustainability viewpoint, district heating is an important option to supply heat to the users in urban areas. The energy convenience of such option depends on the annual energy request, the population density and the efficiency in heat production. Among the alternative technologies, geothermal heat pumps (both open loop and closed loop heat pumps) play a crucial role. In order for the DHN to remain an effective solution with respect to alternative technologies, the optimal configuration, design and operation must be investigated. This thesis aims to propose a methodology for the Multiobjective Optimizations of district heating networks, where the objective functions (the minimum specific primary energy consumption or the minimum economic cost) of a district heating network are investigated using a thermoeconomic based probabilistic procedure. A procedure, derived from Simulating Annealing optimization technique, to select which users in a urban area should be connected with a district heating network and which ones should be heated through an alternative technology is proposed. The goal of this procedure is to reach a globally optimal system from the energy and economic viewpoints. The procedure proposes district heating as the initial choice for all the users. The users are then progressively disconnected to the network, according with the primary energy required to supply them heat, and the alternative technology is considered for disconnected users. Here, ground water heat pump and condensing boilers are considered as the alternative technologies. The optimization technique developed in this PhD thesis develops the three levels of the optimization of energy systems: - Development of a Synthetic Method: The optimal synthesis is performed though a method which starts with a superstructure (where all the buildings (users) in the considered area for the expansion of DH network are supplied by district heating network) and then reduced to the optimal configuration (some of the users are disconnected from the DHN and supplied with an alternative technology such as geothermal heat pumps or condensing boilers). - Development of Optimal Design Method for the components and the properties at the nominal load selected in order to reach optimal performances: - as the users are disconnected from the district heating network, the mass flow rate flowing in the pipes is reduced resulting in different pipe diameters in comparison to the initial configuration. The optimal value velocity in the pipes is obtained as a function of the pipe diameters; - The cogeneration ratio (the ratio between the thermal power of the CHP appliances and the total thermal power installed in the power station ) has been considered as a parameter in the optimal design of the system. - Development of Optimal Operating properties: the operating properties under specific conditions has been changed, like the operating supply temperatures, but also the evolution of the network during its construction is considered. The application to an Italian town is considered as a test case. The main advantage of this procedure is that complex networks, like the DHN in Casale Monferrato characterized by 198 users, grouped in 21 macrozones, can be easily processed. The optimal configuration of the overall urban heating system is obtained. This configuration corresponds to the minimum primary energy request to supply heat to all the users (those connected to the network and those using an alternative heating system). After a brief introduction where the district heating technology is presented, the Thesis is divided in two parts: the first parts introduces the methodological approach proposed for the optimization of a District heating network, together with the description of the optimization model. The second part focuses on a specific application case, showing the preliminary operations required for the application of the model and the results obtained from the optimizations performed. The results have been interpreted trying to reach a more general conclusion which is not related only to the specific case stud

Thermoeconomic cost assessment in future district heating networks

This paper aims at showing the capabilities of thermoeconomic analysis for solving cost assessments in district heating systems both at user and producer sides. In the near future it is expected that multiple producers are allowed to supply heat to the same district heating network, similarly to what happens in the case of the electric grid. Not only the amount of heat they may produce should be properly accounted, but also its quality, and also the pumping power that is requested to supply a unity of thermal energy to the endusers. Moreover, buildings equipped with low temperature heating system allow better use of the thermal energy vector, thus allowing larger efficiency of thermal plants. In the present work, the use of thermoeconomics for the analysis of these aspects is proposed. The approach allows one performing cost assessment in district heating, taking into account the effects of investment and operating costs and thermodynamic irreversibilities in the cost formation of heat from its production in the plants to its use in the buildings. Simple examples are analyzed in order to provide a quantitative evaluation of the various cost terms, depending on the operating conditions, topology and characteristics of the users/producers

Analysis of the annual reports 2017 under the Energy Efficiency Directive: Summary Report

This report discusses the progress towards the 2020 Energy Efficiency targets and towards the implementation of the provisions of the Energy Efficiency Directive 2012/27/EU (EED), providing an overview of the main energy trends in the European Union with special focus on the period 2005-2015. It is based on the last EUROSTAT data available and on the analysis provided by Member States within their Annual Reports 2017, under the EED.JRC.C.2-Energy Efficiency and Renewable

Location data enabling urban sustainable energy planning

Overview of the EULF Energy Pilot UC4: • Goal: To support policy makers to design and implement Energy Efficiency driven renovation plans of building stock at urban level. • Description: Use of existing models, from bottom-up to top-down approach, for the estimation of energy needs at urban level, based on real energy consumption data of a sample of buildings: • for building stock renovation planning and prioritization of interventions, e.g. by class of buildings and/or geographical area of interventions (e.g. in areas having energy distribution networks or in historical centres); • to enable Public Authorities (e.g. Municipalities) to assess the energy saving potential related to the building stock and to local conditions (e.g. climate); • to allow reuse of scaling- up models (from building to urban level) in different climatic conditions and with different characteristics of the building stock

Guidebook How to develop a Sustainable Energy Action Plan (SEAP) in South Mediterranean Cities

This guidebook is adapted to the South Mediterranean context from the Joint Research Centre’s (JRC) guidebook "How to develop a Sustainable Energy Action Plan", developed in 2010 to support the implementation of the Covenant of Mayors (CoM) initiative in European cities. Through the CES-MED project, the European Union has opened the CoM initiative to local authorities of ten southern Mediterranean countries (Algeria, Egypt, Israel, Jordan, Lebanon, Libya, Morocco, Palestine, Syria and Tunisia). The purpose of this guidebook is to make energy efficiency and climate change mitigation measures relevant, achievable and compelling to local authorities in the southern Mediterranean context. Ultimately, it aims to enhance the competitiveness of municipalities and ensure their economic development while reducing dependence on energy imports and fossil fuels through the implementation of energy efficiency, renewable energy and other well-planned climate change mitigation actions at the local level. The guidebook provides detailed, step-by-step guidance to local authorities in southern Mediterranean countries to develop an effective Sustainable Energy Action Plan (SEAP). The process has four phases: initiation, planning, implementation, and monitoring and reporting. The choice and sequence of actions can vary according to the policies and measures already in place. This flexibility allows local authorities to develop a SEAP coherent with and effective for their local circumstances and objectives.JRC.F.7-Renewables and Energy Efficienc

Benchmarking Energy Sustainability in Cities

Energy efficiency is a strategic component of urban sustainability. The aim of this workshop is to address benchmarking techniques in energy efficiency and sustainability as a management tool in the context of urban and local community actions towards sustainability. The workshop also identifies and discusses methodologies and tools to measure urban sustainable energy and energy efficiency in cities. It is well known that standard benchmarking techniques, such as per capita or GDP normalization, are missing important features of the collected data used for benchmarking. Rigorous benchmarking techniques are likely to play an increasingly important role for policy-making authorities and for local authorities to assess their energy efficiency actions, to monitor their performance, exchange experience and learn from each other. In order to develop reliable and robust benchmarking techniques, different databases on energy consumption and location should be integrated with statistical and energy performance assessment methodologies. A special session was dedicated to databases, methodologies and GIS based tools for assessing energy sustainability in urban areas

Proceeding of the Workshop "Benchmarking Energy Sustainability in Cities"

Energy efficiency is a strategic component of urban sustainability. The aim of this workshop is to address benchmarking techniques in energy efficiency and sustainability as a management tool in the context of urban and local community actions towards sustainability. The workshop also identifies and discusses methodologies and tools to measure urban sustainable energy and energy efficiency in cities. It is well known that standard benchmarking techniques, such as per capita or GDP normalization, are missing important features of the collected data used for benchmarking. Rigorous benchmarking techniques are likely to play an increasingly important role for policy-making authorities and for local authorities to assess their energy efficiency actions, to monitor their performance, exchange experience and learn from each other. In order to develop reliable and robust benchmarking techniques, different databases on energy consumption and location should be integrated with statistical and energy performance assessment methodologies. A special session was dedicated to databases, methodologies and GIS based tools for assessing energy sustainability in urban areas.JRC.F.7-Renewables and Energy Efficienc

Covenant of Mayors for Climate and Energy: Default emission factors for local emission inventories – Version 2017

The Covenant of Mayors for Climate and Energy initiative, hereafter called “Covenant” or “CoM”, brings together local and regional authorities voluntarily committing to develop and implement a Sustainable Energy and Climate Action Plan (SECAP) containing measures to reduce their energy (and non-energy) related Greenhouse Gas (GHG) emissions. Within the CoM 2010 guidebook ‘How to develop a Sustainable Energy Action Plan’ (Bertoldi et al., 2010), Part II focuses on the compiling of local GHG emission inventories in the 28 Member States of the European Union (EU). This technical report provides an update of the CoM default emission factors, reported in Part II of the CoM 2010 guidebook and subsequently revised (CoM, 2014; CoM, 2016), together with information on the methodologies, assumptions and data sources, as well as recommendations for their application to the calculation of CO2 and GHG (CO2, CH4 and N2O) emissions due to local use or production of energy (fuel, municipal wastes, renewable energy sources (RES), electricity). As for previous versions, the CoM default emission factors - Version 2017 (expressed in tCO2 or CO2 equivalent/MWh), to be used to estimate standard direct emissions are the IPCC (2006) default factors for stationary combustion for the energy carriers and RES, the most commonly used in the European Union. The CoM default emission factors to estimate local emissions using the Life Cycle Assessment approach, which also includes emissions from the entire supply chain, have been updated using the lastest version (v3.2) of the European Life Cycle Database, as well as other Life Cycle databases and literature reviews. For indirect emissions from local consumption of electricity, national and EU annual factors have been calculated for the 1990 to 2013, using an updated methodological approach and an extended set of energy data (IEA, 2016). The GHG emission factors (in tCO2-eq/MWh) have been estimated using the 100-year time horizon Global Warming Potential factors from the IPCC Fourth Assessment Report (IPCC, 2007), which are the ones currently recommended to the EU countries for the national inventory reporting, in the frame of the United Nations Framework Convention on Climate Change. Regular updates of CoM default emission factors are foreseen for the future. New CoM signatories are therefore recommended to use the latest version of Annex I available from the Covenant on-line library . It is important to note is that the emission factors used to calculate emission inventories should be consistent for the entire implementation process of the SECAP. In particular, since more recent knowledge and technologies can give substantial changes, it is strongly recommended when opting for the use of CoM default emission factors, not to modify the ones applied to the Baseline Emission Inventory during the monitoring phase, in order to identify the trends and changes in local emissions that are due to local energy production and consumption. When selecting the CoM default emission factors, it is also important to ensure that they are appropriate to local fuel quality and composition. If local authorities prefer to use emission factors that better reflect the properties of the fuels used in their territory for the calculation and update of their local emission inventories, they are welcome to do so, when more country specific or local data are available and reliable.JRC.C.5-Air and Climat