Net-Zero/Positive Energy Buildings and Districts

A special issue of Buildings (ISSN 2075-5309). This special issue belongs to the section "Building Energy, Physics, Environment, and Systems".

Deadline for manuscript submissions: closed (30 June 2021) | Viewed by 84360

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Special Issue Editors

VTT Technical Research Centre of Finland, FI-02044 VTT Espoo, Finland
Interests: energy in buildings and communities; renwable energy integration; simulation and optimization of buildings’ performance
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 Espoo, Finland
Interests: positive energy district; energy transition; carbon-free community
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Buildings use approximately 40% of all energy produced globally. Energy in buildings and districts is one of the main potential fields for the mitigation of emissions. This can be done by enhancing the energy efficiency of buildings, by using advanced buildings’ designs, envelopes, and HVAC system components. In addition, and in order to reach carbon neutrality, it is necessary to integrate suitable onsite renewable energy generation, conversion, and storage technologies, which can offset imported energy from grids. Accordingly, various raising concepts for net-zero/positive energy buildings and districts (NZPEBD) have emerged in the recent years to shape cities into carbon neutral communities in the near future.

For this Special Issue, authors are kindly invited to submit high-quality papers on one or more of the following topics related to net-zero/positive energy buildings and districts (NZPEBD):

  • Definitions of NZPEBD, including the spatial boundary of balance, temporal framework, target energy, and exchanged credits (site-energy, primary energy, CO2 emissions, etc.);
  • New buildings and the renovation of old buildings, including heritage and historical buildings and districts’ new energy concepts, to NZPEBD levels;
  • KPIs development for NZPEBD;
  • Energy flexibility in NZPEBD;
  • Simulation and optimization methods;
  • Economic feasibility of NZPEBD;
  • Social aspects of NZPEBD;
  • Energy transition pathways towards NZPEBD;
  • Practical challenges and barriers for NZPEBD emergence and development;
  • Experience from construction, operation, and monitoring of NZPEBD demos.
Papers addressing other related topics will also be considered.

Dr. Ala Hasan
Dr. Francesco Reda
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Buildings is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Net- and nearly-zero-energy buildings
  • Positive energy communities and districts
  • Renewable energy integration
  • Energy flexibility in buildings and communities
  • Simulation and optimization methods
  • Economic studies
  • Social acceptance
  • Energy transition
  • Practical experience from demo sites.

Published Papers (18 papers)

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Editorial

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3 pages, 175 KiB  
Editorial
Special Issue “Net-Zero/Positive Energy Buildings and Districts”
by Ala Hasan and Francesco Reda
Buildings 2022, 12(3), 382; https://doi.org/10.3390/buildings12030382 - 21 Mar 2022
Viewed by 2028
Abstract
The important goal of decarbonization of communities and cities has resulted in the emergence of new concepts and implementations of Net-Zero/Positive-Energy Buildings and Districts (NZPEBD) in recent years [...] Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)

Research

Jump to: Editorial, Review, Other

16 pages, 596 KiB  
Article
Integrating Plus Energy Buildings and Districts with the EU Energy Community Framework: Regulatory Opportunities, Barriers and Technological Solutions
by Andreas Tuerk, Dorian Frieden, Camilla Neumann, Konstantinos Latanis, Anastasios Tsitsanis, Spyridon Kousouris, Javier Llorente, Ismo Heimonen, Francesco Reda, Mia Ala-Juusela, Koen Allaerts, Chris Caerts, Thomas Schwarzl, Martin Ulbrich, Annette Stosch and Thomas Ramschak
Buildings 2021, 11(10), 468; https://doi.org/10.3390/buildings11100468 - 12 Oct 2021
Cited by 16 | Viewed by 3405
Abstract
The aim of this paper is to assess opportunities the Clean Energy Package provides for Plus Energy Buildings (PEBs) and Plus Energy Districts (PEDs) regarding their economic optimization and market integration, possibly leading to new use cases and revenue streams. At the same [...] Read more.
The aim of this paper is to assess opportunities the Clean Energy Package provides for Plus Energy Buildings (PEBs) and Plus Energy Districts (PEDs) regarding their economic optimization and market integration, possibly leading to new use cases and revenue streams. At the same time, insights into regulatory limitations at the national level in transposing the set of EU Clean Energy Package provisions are shown. The paper illustrates that the concepts of PEBs and PEDs are in principle compatible with the EU energy community concepts, as they relate to technical characteristics while energy communities provide a legal and regulatory framework for the organization and governance of a community, at the same time providing new regulatory space for specific activities and market integration. To realize new use cases, innovative ICT approaches are needed for a range of actors actively involved in creating and operating energy communities as presented in the paper. The paper discusses a range of different options to realize PEBs and PEDs as energy communities based on the H2020 EXCESS project. It concludes, however, that currently the transposition of the Clean Energy Package by the EU Member States is incomplete and limiting and as a consequence, in the short term, the full potential of PEBs and PEDs cannot be exploited. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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27 pages, 79881 KiB  
Article
Strategies of Design Concepts and Energy Systems for Nearly Zero-Energy Container Buildings (NZECBs) in Different Climates
by Johannes Koke, André Schippmann, Jingchun Shen, Xingxing Zhang, Peter Kaufmann and Stefan Krause
Buildings 2021, 11(8), 364; https://doi.org/10.3390/buildings11080364 - 18 Aug 2021
Cited by 8 | Viewed by 4626
Abstract
Container-based lightweight buildings offer a high ecologic and economic potential when they are designed as nearly zero-energy container buildings (NZECBs). Thus, they are relevant to energy transition in achieving an almost climate-neutral building stock. This paper describes and applies design strategies for suitable [...] Read more.
Container-based lightweight buildings offer a high ecologic and economic potential when they are designed as nearly zero-energy container buildings (NZECBs). Thus, they are relevant to energy transition in achieving an almost climate-neutral building stock. This paper describes and applies design strategies for suitable building concepts and energy systems to be used in NZECBs for different climates. Therefore, different applications in representative climatic zones were selected. Initially, the global climate zones were characterized and analyzed with regard to their potential for self-sufficiency and renewable energies in buildings. The design strategies were further developed and demonstrated for three cases: a single-family house in Sweden, a multi-family house in Germany, and a small school building in rural Ethiopia. For each case, design guidelines were derived and building concepts were developed. On the basis of these input data, various energy concepts were developed in which solar and wind energy, as well as biomass, were integrated as renewable energy sources. All the concepts were simulated and analyzed with the Polysun® software. The various approaches were compared and evaluated, particularly with regard to energy self-sufficiency. Self-sufficiency rates up to 80% were achieved. Finally, the influence of different climate zones on the energy efficiency of the single-family house was studied as well as the influence of the size of battery storage and insulation. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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23 pages, 3361 KiB  
Article
Agent Based Modelling of a Local Energy Market: A Study of the Economic Interactions between Autonomous PV Owners within a Micro-Grid
by Marco Lovati, Pei Huang, Carl Olsmats, Da Yan and Xingxing Zhang
Buildings 2021, 11(4), 160; https://doi.org/10.3390/buildings11040160 - 14 Apr 2021
Cited by 15 | Viewed by 3067
Abstract
Urban Photovoltaic (PV) systems can provide large fractions of the residential electric demand at socket parity (i.e., a cost below the household consumer price). This is obtained without necessarily installing electric storage or exploiting tax funded incentives. The benefits of aggregating the electric [...] Read more.
Urban Photovoltaic (PV) systems can provide large fractions of the residential electric demand at socket parity (i.e., a cost below the household consumer price). This is obtained without necessarily installing electric storage or exploiting tax funded incentives. The benefits of aggregating the electric demand and renewable output of multiple households are known and established; in fact, regulations and pilot energy communities are being implemented worldwide. Financing and managing a shared urban PV system remains an unsolved issue, even when the profitability of the system as a whole is demonstrable. For this reason, an agent-based modelling environment has been developed and is presented in this study. It is assumed that an optimal system (optimized for self-sufficiency) is shared between 48 households in a local grid of a positive energy district. Different scenarios are explored and discussed, each varying in number of owners (agents who own a PV system) and their pricing behaviour. It has been found that a smaller number of investors (i.e., someone refuse to join) provokes an increase of the earnings for the remaining investors (from 8 to 74% of the baseline). Furthermore, the pricing strategy of an agent shows improvement potential without knowledge of the demand of others, and thus it has no privacy violations. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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17 pages, 1615 KiB  
Article
IEA EBC Annex83 Positive Energy Districts
by Åsa Hedman, Hassam Ur Rehman, Andrea Gabaldón, Adriano Bisello, Vicky Albert-Seifried, Xingxing Zhang, Francesco Guarino, Steinar Grynning, Ursula Eicker, Hans-Martin Neumann, Pekka Tuominen and Francesco Reda
Buildings 2021, 11(3), 130; https://doi.org/10.3390/buildings11030130 - 20 Mar 2021
Cited by 57 | Viewed by 6911
Abstract
At a global level, the need for energy efficiency and an increased share of renewable energy sources is evident, as is the crucial role of cities due to the rapid urbanization rate. As a consequence of this, the research work related to Positive [...] Read more.
At a global level, the need for energy efficiency and an increased share of renewable energy sources is evident, as is the crucial role of cities due to the rapid urbanization rate. As a consequence of this, the research work related to Positive Energy Districts (PED) has accelerated in recent years. A common shared definition, as well as technological approaches or methodological issues related to PEDs are still unclear in this development and a global scientific discussion is needed. The International Energy Agency’s Energy in Buildings and Communities Programme (IEA EBC) Annex 83 is the main platform for this international scientific debate and research. This paper describes the challenges of PEDs and the issues that are open for discussions and how the Annex 83 is planned and organized to facilitate this and to actively steer the development of PEDs major leaps forward. The main topics of discussion in the PED context are the role and importance of definitions of PEDs, virtual and geographical boundaries in PEDs, the role of different stakeholders, evaluation approaches, and the learnings of realized PED projects. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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20 pages, 1704 KiB  
Article
Citizens and Positive Energy Districts: Are Espoo and Leipzig Ready for PEDs?
by Zarrin Fatima, Uta Pollmer, Saga-Sofia Santala, Kaisa Kontu and Marion Ticklen
Buildings 2021, 11(3), 102; https://doi.org/10.3390/buildings11030102 - 6 Mar 2021
Cited by 15 | Viewed by 3404
Abstract
In urban transformation, no solution works without citizen support. With increasing numbers of building technologies and large-scale urban development on its way across cities, it has become vital to keep citizens informed, engaged, and content with the new changes. This paper looks at [...] Read more.
In urban transformation, no solution works without citizen support. With increasing numbers of building technologies and large-scale urban development on its way across cities, it has become vital to keep citizens informed, engaged, and content with the new changes. This paper looks at citizen engagement in Espoo (Finland) and Leipzig (Germany), and it determines whether the cities are ready for developing and implementing positive energy districts (PEDs). The authors studied the cities’ operations and current citizen engagement methods to understand how the efforts could be combined and improved. The analysis indicated that the city of Espoo already has a well-established system that continuously promotes citizen engagement at various levels, and combining the available infrastructure with company experts on citizen participation will allow Espoo to seamlessly transition towards PEDs in the near future. The city of Leipzig has a rich experience due to several national projects and participation in an earlier European project, which enabled the city to set clearer goals for the future and modify existing citizen methods. As lighthouse cities, findings from Espoo and Leipzig are also aimed at cities across Europe and beyond to boost development of PEDs together with citizens. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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23 pages, 2573 KiB  
Article
Obstacles to Developing Net-Zero Energy (NZE) Homes in Greater Toronto Area
by Ghazal Makvandia and Md. Safiuddin
Buildings 2021, 11(3), 95; https://doi.org/10.3390/buildings11030095 - 4 Mar 2021
Cited by 15 | Viewed by 3991
Abstract
Efforts have been put in place to minimize the effects of construction activities and occupancy, but the problem of greenhouse gas (GHG) emissions continues to have detrimental effects on the environment. As an effort to reduce GHG emissions, particularly carbon emissions, countable commercial, [...] Read more.
Efforts have been put in place to minimize the effects of construction activities and occupancy, but the problem of greenhouse gas (GHG) emissions continues to have detrimental effects on the environment. As an effort to reduce GHG emissions, particularly carbon emissions, countable commercial, industrial, institutional, and residential net-zero energy (NZE) buildings were built around the globe during the past few years, and they are still operating. But there exist many challenges and barriers for the construction of NZE buildings. This study identifies the obstacles to developing NZE buildings, with a focus on single-family homes, in the Greater Toronto Area (GTA). The study sought to identify the technical, organizational, and social challenges of constructing NZE buildings, realize the importance of the public awareness in making NZE homes, and provide recommendations on how to raise public knowledge. A qualitative approach was employed to collect the primary data through survey and interviews. The secondary data obtained from the literature review were also used to realize the benefits, challenges, and current situation of NZE buildings. Research results indicate that the construction of NZE buildings is faced with a myriad of challenges, including technical issues, the lack of governmental and institutional supports, and the lack of standardized measures. The public awareness of NZE homes has been found to be very low, thus limiting the uptake and adoption of the new technologies used in this type of homes. The present study also recommends that the government and the academic institutions should strive to support the NZE building technology through curriculum changes, technological uptake, and financial incentives to buyers and developers. The implementation of these recommendations may enhance the success and popularity of NZE homes in the GTA. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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24 pages, 2906 KiB  
Article
Challenges and Barriers for Net‐Zero/Positive Energy Buildings and Districts—Empirical Evidence from the Smart City Project SPARCS
by Daria Uspenskaia, Karl Specht, Hendrik Kondziella and Thomas Bruckner
Buildings 2021, 11(2), 78; https://doi.org/10.3390/buildings11020078 - 23 Feb 2021
Cited by 26 | Viewed by 5710
Abstract
Without decarbonizing cities energy and climate objectives cannot be achieved as cities account for approximately two thirds of energy consumption and emissions. This goal of decarbonizing cities has to be facilitated by promoting net-zero/positive energy buildings and districts and replicating them, driving cities [...] Read more.
Without decarbonizing cities energy and climate objectives cannot be achieved as cities account for approximately two thirds of energy consumption and emissions. This goal of decarbonizing cities has to be facilitated by promoting net-zero/positive energy buildings and districts and replicating them, driving cities towards sustainability goals. Many projects in smart cities demonstrate novel and groundbreaking low-carbon solutions in demonstration and lighthouse projects. However, as the historical, geographic, political, social and economic context of urban areas vary greatly, it is not always easy to repeat the solution in another city or even district. It is therefore important to look for the opportunities to scale up or repeat successful pilots. The purpose of this paper is to explore common trends in technologies and replication strategies for positive energy buildings or districts in smart city projects, based on the practical experience from a case study in Leipzig—one of the lighthouse cities in the project SPARCS. One of the key findings the paper has proven is the necessity of a profound replication modelling to deepen the understanding of upscaling processes. Three models analyzed in this article are able to provide a multidimensional representation of the solution to be replicated. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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22 pages, 1759 KiB  
Article
Optimising the Parameters of a Building Envelope in the East Mediterranean Saharan, Cool Climate Zone
by Aiman Albatayneh
Buildings 2021, 11(2), 43; https://doi.org/10.3390/buildings11020043 - 27 Jan 2021
Cited by 28 | Viewed by 3491
Abstract
Enhancing the energy efficiency and environmental sustainability of buildings is a significant global aim. New construction regulations are, therefore, geared specifically towards low-emission and energy-efficient projects. However, there are numerous and typically competitive priorities, such as making the most of energy usage in [...] Read more.
Enhancing the energy efficiency and environmental sustainability of buildings is a significant global aim. New construction regulations are, therefore, geared specifically towards low-emission and energy-efficient projects. However, there are numerous and typically competitive priorities, such as making the most of energy usage in residential buildings. This leads to the complex topic of multi-objective optimisation. The primary aim of this research was to reduce the energy consumed for heating and cooling loads in residential buildings in Ma’an City, which is located in the Jordanian Saharan Mediterranean, a cool climate zone. This was achieved by optimising various design variables (window to wall percent, ground floor construction, local shading type, infiltration rate (ac/h), glazing type, flat roof construction, natural ventilation rate, window blind type, window shading control schedule, partition construction, site orientation and external wall construction) of the building envelope. DesignBuilder software (version 6.1) was utilised to run a sensitivity analysis (SA) for 12 design variables to evaluate their influence on both heating and cooling loads simultaneously using a regression method. The variables were divided into two groups according to their importance and a genetic algorithm (GA) was then applied to both groups. The optimum solution selected for the high-importance variables was based on minimising the heating and cooling loads. The optimum solution selected for the low-importance variables was based on the lowest summation of the heating and cooling loads. Finally, a scenario was devised (using the combined design variables of the two solutions) and simulated. The results indicate that the total energy consumption was 1186.21 kWh/year, divided into 353.03 kWh/year for the cooling load and 833.18 kWh/year for the heating load. This was compared with 9969.38 kWh/year of energy, divided into 3878.37 kWh/year for the heating load and 6091.01 kWh/year for the cooling load for the baseline building. Thus, the amount of energy saved was 88.1%, 94.2% and 78.5% for total energy consumption, cooling load and heating load, respectively. However, implementing the modifications suggested by the optimisation of the low-importance variables was not cost-effective, especially the external wall construction and partition construction, and therefore these design variables can be neglected in future studies. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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19 pages, 4022 KiB  
Article
An Approach to Data Acquisition for Urban Building Energy Modeling Using a Gaussian Mixture Model and Expectation-Maximization Algorithm
by Mengjie Han, Zhenwu Wang and Xingxing Zhang
Buildings 2021, 11(1), 30; https://doi.org/10.3390/buildings11010030 - 16 Jan 2021
Cited by 15 | Viewed by 3428
Abstract
In recent years, a building’s energy performance is becoming uncertain because of factors such as climate change, the Covid-19 pandemic, stochastic occupant behavior and inefficient building control systems. Sufficient measurement data is essential to predict and manage a building’s performance levels. Assessing energy [...] Read more.
In recent years, a building’s energy performance is becoming uncertain because of factors such as climate change, the Covid-19 pandemic, stochastic occupant behavior and inefficient building control systems. Sufficient measurement data is essential to predict and manage a building’s performance levels. Assessing energy performance of buildings at an urban scale requires even larger data samples in order to perform an accurate analysis at an aggregated level. However, data are not only expensive, but it can also be a real challenge for communities to acquire large amounts of real energy data. This is despite the fact that inadequate knowledge of a full population will lead to biased learning and the failure to establish a data pipeline. Thus, this paper proposes a Gaussian mixture model (GMM) with an Expectation-Maximization (EM) algorithm that will produce synthetic building energy data. This method is tested on real datasets. The results show that the parameter estimates from the model are stable and close to the true values. The bivariate model gives better performance in classification accuracy. Synthetic data points generated by the models show a consistent representation of the real data. The approach developed here can be useful for building simulations and optimizations with spatio-temporal mapping. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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31 pages, 4762 KiB  
Article
Positioning Positive Energy Districts in European Cities
by Oscar Lindholm, Hassam ur Rehman and Francesco Reda
Buildings 2021, 11(1), 19; https://doi.org/10.3390/buildings11010019 - 4 Jan 2021
Cited by 78 | Viewed by 11497
Abstract
There are many concepts for buildings with integrated renewable energy systems that have received increased attention during the last few years. However, these concepts only strive to streamline building-level renewable energy solutions. In order to improve the flexibility of decentralized energy generation, individual [...] Read more.
There are many concepts for buildings with integrated renewable energy systems that have received increased attention during the last few years. However, these concepts only strive to streamline building-level renewable energy solutions. In order to improve the flexibility of decentralized energy generation, individual buildings and energy systems should be able to interact with each other. The positive energy district (PED) concept highlights the importance of active interaction between energy generation systems, energy consumers and energy storage within a district. This paper strives to inform the public, decision makers and fellow researchers about the aspects that should be accounted for when planning and implementing different types of PEDs in different regions throughout the European Union. The renewable energy environment varies between different EU regions, in terms of the available renewable energy sources, energy storage potential, population, energy consumption behaviour, costs and regulations, which affect the design and operation of PEDs, and hence, no PED is like the other. This paper provides clear definitions for different types of PEDs, a survey of the renewable energy market circumstances in the EU and a detailed analysis of factors that play an essential role in the PED planning process. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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23 pages, 2807 KiB  
Article
Emission Reduction Potential of Different Types of Finnish Buildings through Energy Retrofits
by Janne Hirvonen, Juha Jokisalo, Paula Sankelo, Tuomo Niemelä and Risto Kosonen
Buildings 2020, 10(12), 234; https://doi.org/10.3390/buildings10120234 - 8 Dec 2020
Cited by 10 | Viewed by 4496
Abstract
Energy retrofitting of buildings shows great potential in reducing CO2 emissions. However, most retrofitting studies only focus on a single building type. This paper shows the relative potential in six Finnish building types, to identify possible focus areas for future retrofits in [...] Read more.
Energy retrofitting of buildings shows great potential in reducing CO2 emissions. However, most retrofitting studies only focus on a single building type. This paper shows the relative potential in six Finnish building types, to identify possible focus areas for future retrofits in Finland. Data from previous optimization studies was used to provide optimal cases for comparison. Energy demand of the buildings was generated through dynamic simulation with the IDA-ICE software. The cases were compared according to emissions reduction, investment and life cycle cost. It was found that, in all buildings, it was possible to reduce emissions cost-neutrally by 20% to 70% in buildings with district heating and by 70% to 95% using heat pumps. Single-family homes with oil or wood boilers switching to heat pumps had the greatest emission reduction potential. More stringent requirements for energy efficiency could be mandated during building renovation. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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19 pages, 4070 KiB  
Article
Waste Incineration Heat and Seasonal Thermal Energy Storage for Promoting Economically Optimal Net-Zero Energy Districts in Finland
by Janne Hirvonen and Risto Kosonen
Buildings 2020, 10(11), 205; https://doi.org/10.3390/buildings10110205 - 17 Nov 2020
Cited by 9 | Viewed by 3406
Abstract
In countries with high heating demand, waste heat from industrial processes should be carefully utilized in buildings. Finland already has an extensive district heating grid and large amounts of combined heat and power generation. However, despite the average climate, there is little use [...] Read more.
In countries with high heating demand, waste heat from industrial processes should be carefully utilized in buildings. Finland already has an extensive district heating grid and large amounts of combined heat and power generation. However, despite the average climate, there is little use for excess heat in summer. Waste incineration plants need to be running regardless of weather, so long-term storage of heat requires consideration. However, no seasonal energy storage systems are currently in operation in connection with Finnish waste incineration plants. This study used dynamic energy simulation performed with the TRNSYS 17 software to analyze the case of utilizing excess heat from waste incineration to supplement conventional district heating of a new residential area. Seasonal energy storage was utilized through a borehole thermal energy storage (BTES) system. Parametric runs using 36 different storage configurations were performed to find out the cost and performance range of such plans. Annual energy storage efficiencies from 48% to 69% were obtained for the BTES. Waste heat could generate 37–89% of the annual heat demand. Cost estimations of waste heat storage using BTES are not available in the literature. As an important finding in this study, a levelized cost of heat of 10.5–23.5 €/MWh was obtained for various BTES configurations used for incineration waste heat storage. In the three most effective cases, the stored heat reduced annual CO2 emissions of the residential area by 42%, 64% and 86%. Thus, the solution shows great potential for reducing carbon emissions of district heating in grids connected to waste incineration plants. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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30 pages, 8855 KiB  
Article
Digital Mapping of Techno-Economic Performance of a Water-Based Solar Photovoltaic/Thermal (PVT) System for Buildings over Large Geographical Cities
by Santhan Reddy Penaka, Puneet Kumar Saini, Xingxing Zhang and Alejandro del Amo
Buildings 2020, 10(9), 148; https://doi.org/10.3390/buildings10090148 - 27 Aug 2020
Cited by 6 | Viewed by 3901
Abstract
Solar photovoltaic thermal (PVT) is an emerging technology capable of producing electrical and thermal energy using a single collector. However, to achieve larger market penetration of this technology, it is imperative to have an understanding of the energetic performance for different climatic conditions [...] Read more.
Solar photovoltaic thermal (PVT) is an emerging technology capable of producing electrical and thermal energy using a single collector. However, to achieve larger market penetration of this technology, it is imperative to have an understanding of the energetic performance for different climatic conditions and the economic performance under various financial scenarios. This paper thus presents a techno-economic evaluation of a typical water-based PVT system for a single-family house to generate electricity and domestic hot water applications in 85 locations worldwide. The simulations are performed using a validated tool with one-hour time step for output. The thermal performance of the collector is evaluated using energy utilization ratio and exergy efficiency as key performance indicators, which are further visualized by the digital mapping approach. The economic performance is assessed using net present value and payback period under two financial scenarios: (1) total system cost as a capital investment in the first year; (2) only 25% of total system cost is a capital investment and the remaining 75% investment is considered for a financing period with a certain interest rate. The results show that such a PVT system has better energy and exergy performance for the locations with a low annual ambient temperature and vice versa. Furthermore, it is seen that the system boundaries, such as load profile, hot water storage volume, etc., can have a significant effect on the annual energy production of the system. Economic analysis indicates that the average net present values per unit collector area are 1800 and 2200 EUR, respectively, among the 85 cities for financial model 1 and financial model 2. Nevertheless, from the payback period point of view, financial model 1 is recommended for locations with high interest rate. The study is helpful to set an understanding of general factors influencing the techno-economic performance dynamics of PVT systems for various locations. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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21 pages, 3219 KiB  
Article
Optimal Simulation of Three Peer to Peer (P2P) Business Models for Individual PV Prosumers in a Local Electricity Market Using Agent-Based Modelling
by Marco Lovati, Xingxing Zhang, Pei Huang, Carl Olsmats and Laura Maturi
Buildings 2020, 10(8), 138; https://doi.org/10.3390/buildings10080138 - 29 Jul 2020
Cited by 32 | Viewed by 4687
Abstract
Solar photovoltaic (PV) is becoming one of the most significant renewable sources for positive energy district (PED) in Sweden. The lack of innovative business models and financing mechanisms are the main constraints for PV’s deployment installed in local communities. This paper therefore proposes [...] Read more.
Solar photovoltaic (PV) is becoming one of the most significant renewable sources for positive energy district (PED) in Sweden. The lack of innovative business models and financing mechanisms are the main constraints for PV’s deployment installed in local communities. This paper therefore proposes a peer-to-peer (P2P) business model for 48 individual building prosumers with PV installed in a Swedish community. It considers energy use behaviour, electricity/financial flows, ownerships and trading rules in a local electricity market. Different local electricity markets are designed and studied using agent-based modelling technique, with different energy demands, cost–benefit schemes and financial hypotheses for an optimal evaluation. This paper provides an early insight into a vast research space, i.e., the operation of an energy system through the constrained interaction of its constituting agents. The agents (48 households) show varying abilities in exploiting the common PV resource, as they achieve very heterogeneous self-sufficiency levels (from ca. 15% to 30%). The lack of demand side management suggests that social and lifestyle differences generate huge impacts on the ability to be self-sufficient with a shared, limited PV resource. Despite the differences in self-sufficiency, the sheer energy amount obtained from the shared PV correlates mainly with annual cumulative demand. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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27 pages, 12254 KiB  
Article
A MILP Optimization Method for Building Seasonal Energy Storage: A Case Study for a Reversible Solid Oxide Cell and Hydrogen Storage System
by Oscar Lindholm, Robert Weiss, Ala Hasan, Frank Pettersson and Jari Shemeikka
Buildings 2020, 10(7), 123; https://doi.org/10.3390/buildings10070123 - 9 Jul 2020
Cited by 11 | Viewed by 4468
Abstract
A new method for the optimization of seasonal energy storage is presented and applied in a case study. The optimization method uses an interval halving approach to solve computationally demanding mixed integer linear programming (MILP) problems with both integer and non-integer operation variables [...] Read more.
A new method for the optimization of seasonal energy storage is presented and applied in a case study. The optimization method uses an interval halving approach to solve computationally demanding mixed integer linear programming (MILP) problems with both integer and non-integer operation variables (variables that vary from time step to time step in during energy storage system operation). The seasonal energy storage in the case study uses a reversible solid oxide cell (RSOC) to convert electricity generated by solar photovoltaic (PV) panels into hydrogen gas and to convert hydrogen gas back to electricity while also generating some heat. Both the case study results and the optimization method accuracy are examined and discussed in the paper. In the case study, the operation of the RSOC and hydrogen storage system is compared with the operation of a reference system without energy storage. The results of the study show that installing an RSOC and hydrogen storage system could increase the utilization of onsite renewable energy generation significantly. Overall, the optimization method presents a relatively accurate solution to the case study optimization problem and a sensibility analysis shows a clear and logical pattern. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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Review

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24 pages, 5806 KiB  
Review
Characterizing Positive Energy District (PED) through a Preliminary Review of 60 Existing Projects in Europe
by Xingxing Zhang, Santhan Reddy Penaka, Samhita Giriraj, Maria Nuria Sánchez, Paolo Civiero and Han Vandevyvere
Buildings 2021, 11(8), 318; https://doi.org/10.3390/buildings11080318 - 24 Jul 2021
Cited by 46 | Viewed by 5642
Abstract
Positive Energy District (PED) is recently proposed to be an integral part of a district/urban energy system with a corresponding positive influence. Thus, the PED concept could become the key solution to energy system transition towards carbon neutrality. This paper intends to report [...] Read more.
Positive Energy District (PED) is recently proposed to be an integral part of a district/urban energy system with a corresponding positive influence. Thus, the PED concept could become the key solution to energy system transition towards carbon neutrality. This paper intends to report and visualize the initial analytical results of 60 existing PED projects in Europe about their main characteristics, including geographical information, spatial-temporal scale, energy concepts, building archetypes, finance source, keywords, finance model and challenges/barriers. As a result, a dedicated date base is developed and it could be further expanded/interoperated through an interactive dashboard. It is found that Norway and Italy have the most PED projects so far. Many PED projects state a ‘yearly’ time scale while nearly 1/3 projects have less than 0.2 km2 area in terms of spatial scale. The private investment together with regional/national grants is commonly observed. A mixture of residential, commercial and office/social buildings are found. The most common renewable energy systems include solar energy, district heating/cooling, wind and geothermal energy. Challenges and barriers for PED related projects vary from the planning stage to the implementation stage. Furthermore, the text mining approach is applied to examine the keywords or concentrations of PED-related projects at different stages. These preliminary results are expected to give useful guidance for future PED definitions and proposals of ‘reference PED’. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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20 pages, 6162 KiB  
Case Report
A Top-Down Digital Mapping of Spatial-Temporal Energy Use for Municipality-Owned Buildings: A Case Study in Borlänge, Sweden
by Samer Quintana, Pei Huang, Mengjie Han and Xingxing Zhang
Buildings 2021, 11(2), 72; https://doi.org/10.3390/buildings11020072 - 18 Feb 2021
Cited by 7 | Viewed by 2704
Abstract
Urban energy mapping plays a crucial role in benchmarking the energy performance of buildings for many stakeholders. This study examined a set of buildings in the city of Borlänge, Sweden, owned by the municipality. The aim was to present a digital spatial map [...] Read more.
Urban energy mapping plays a crucial role in benchmarking the energy performance of buildings for many stakeholders. This study examined a set of buildings in the city of Borlänge, Sweden, owned by the municipality. The aim was to present a digital spatial map of both electricity use and district heating demand in the spatial–temporal dimension. A toolkit for top-down data processing and analysis was considered based on the energy performance database of municipality-owned buildings. The data were initially cleaned, transformed and geocoded using custom scripts and an application program interface (API) for OpenStreetMap and Google Maps. The dataset consisted of 228 and 105 geocoded addresses for, respectively, electricity and district heating monthly consumption for the year 2018. A number of extra parameters were manually incorporated to this data, i.e., the total floor area, the building year of construction and occupancy ratio. The electricity use and heating demand in the building samples were about 24.47 kWh/m2 and 268.78 kWh/m2, respectively, for which great potential for saving heating energy was observed. Compared to the electricity use, the district heating showed a more homogenous pattern following the changes of the seasons. The digital mapping revealed a spatial representation of identifiable hotspots for electricity uses in high-occupancy/density areas and for district heating needs in districts with buildings mostly constructed before 1980. These results provide a comprehensive means of understanding the existing energy distributions for stakeholders and energy advisors. They also facilitate strategy geared towards future energy planning in the city, such as energy benchmarking policies. Full article
(This article belongs to the Special Issue Net-Zero/Positive Energy Buildings and Districts)
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