• Energy Research

Abstract. This document introduces the process for the creation of a testbed for energy applications based on a semantic 3D city model for the municipality of Rijssen-Holten in The Netherlands. The creation of this dataset requires the consolidation from multiple data sources as well as a lot of manual work so the authors can warranty as much as possible the quality of the dataset so in can be used in several use cases. The data is stored following the OGC standard CityGML v2.0 and contain the geometrical and semantical information of CityObjects from the thematic modules Building, Vegetation and Relief. This data set consolidates the open weather data from the closest weather station to the study area located in Heino in the Netherlands. We discuss the decisions taken during the manual data collection process and we present some use cases that have already consume the dataset at the time of writing this document.

Urban densification increases the number of people living in urban areas and is hypothesized to be a more efficient use of available land than urban sprawl. The objective of this study was to quantify the operational and embodied emissions created as a result of densification. A ‘Business as usual’ and a ‘Concentrated’ densification strategy were investigated. When densifying at the neighbourhood level, existing buildings can either be replaced or extended to accommodate the additional inhabitants. The densification strategies were applied to two reference urban design neighbourhoods in Switzerland. The ‘Typical’ approach assumed that all the buildings were demolished and rebuilt and the ‘Preserve-existing’ approach involved the extension of existing buildings as much as possible. Construction material choice and modification of the built form were the sources of embodied emissions considered for each strategy. Urban building energy modelling was used to calculate the emissions incurred by heating the buildings and the embodied emissions were calculated using building standards. The operational performance was simulated assuming both a gas boiler and an electric heat pump to determine the influence of the heating system type on the operational emissions. This study found that savings of approximately 30% in embodied emissions can be achieved by extending the existing building stock rather than rebuilding. However, these savings represent a relatively small percentage of the total emissions incurred throughout a building's lifetime and the savings further diminish in the concentrated densification strategies. Energy and Buildings, 276 ISSN:1872-6178 ISSN:0378-7788

Building simulation supports the conceptual design, planning and operation of innovative and economical energy supply options for buildings and cities. Typical applications of Urban Building Energy Modeling are quantification of the impact of retrofits or the optimization of heat transfer of district heating networks. The necessary input data for design-driven building simulation are often not available for existing buildings. Archetypes are used to fill the missing information and thus enable a dynamic simulation of a large number of existing buildings. The simulation results of archetypes show differences to hourly measured data of individual buildings due to statistical and discrete assumptions. To improve the description and prediction of individual buildings, the calibration of simulation models is key. This thesis describes a method for automated calibration of individual urban building simulation models using hourly measurement data. The proposed framework automates all necessary steps from model generation, selection of sensitive parameters, calibration, and evaluation using statistical indices. The model generation uses the standardized information model CityGML and its extension EnergyADE and utilizes all available building data. In addition, further building parameters are identified with the help of the analysis of existing measurement data. The selection of sensitive parameters is done for each building and thus takes into account specific building characteristics. Bayesian calibration is used as the calibration method, which is particularly characterized by the determination of probability distributions. Hourly measurements are considered in calibration and evaluation of the simulation results with a combination of several statistical indices. The application of the framework to emulated and real buildings helps to better understand the strengths and weaknesses of automated calibrations for building models. It was shown that the reliability of automated calibration cannot be evaluated based on simulation results alone, but the calibrated parameter values have to be taken into account. In this context, compensation effects were described in detail. It could be shown that the more information is used for the parameterization of the initial building model and the more measurement data is available in hourly resolution, the better is the calibration of the models in comparison to the simulation results and the lower are compensation effects.

In this master thesis, a methodology is proposed for building stock classification and archetype building development based on deterministic information available in Energy Performance Certificates (EPCs) of existing buildings in the city of Uppsala.This study aims to answer if the EPC database can be used as a reliable data source for archetype development and further UBEM models.The EPC data is cleaned and organised using Matlab. The building stock is then categorised into archetypes by energy performance and building characteristics and a model of each archetype building is created in the software EnergyPlus.The South-West part of Uppsala is used as a case study and to represent the building stock of that area 20 archetypes is developed. Simulations in EnergyPlus shows that the defined archetypes is a reliable estimation of buildings in Sweden with the same characteristics and construction period.By using GIS data the results can be aggregated to city level with the resulting total energy demand for heating calculated to 1455,7 GWh, compared to the actual value of 1397,0 GWh.The lack of validation data on a smaller scale is a large issue for this study, as well as some issues with data reliability in the EPCs. Despite this, the results of this study points to that the gathered values are a decent enough estimate to make a reliable assumption of the total energy demand for heating. The EPCs thus provide a useful source of data for energy demand purposes and building characteristics.

This project aims to contribute to the energy mapping of Visby’s building stock. Using energy performance certificates data, the building stock can be categorized after defining energy related parameters. From every category, an archetype building is developed from the mean value of interesting parameters in each group. The goal is to create distinct categories which as well as possible represents the building stock. This study commences with an inventory of Visby’s building stock to create an overall picture. Thereafter categories of the building stock are examined on the basis of interesting parameters that supposedly have an impact on the building’s energy consumption. The purpose is to examine which parameters that together catches the most representative picture of Visby’s building stock. The energy performance of the buildings is the main factor for comparison. Parameters that are used in the categorization process are: Building type, location of the buildings, building volume, type code, year of construction, heating system and number of floors. From the determined categorizations, archetypes are developed and type buildings can be represented. This study only examines residential buildings. Two times during the study, abnormal values were removed from the used material. The cleaning of abnormal values prevents that a few values which are considered as abnormal gives a wrong picture of the building stocks characteristics. The first analysis of the parameters leads to 6 examined categorizations where two are selected, one for single family housing and one for multi-family housing. Parameters that best defines single family housing are year of construction, heating system and building volume. Parameters that best defines multi-family housing are year of construction and building volume. The established categorization covers 92% of the building stock and 205 buildings are erased by the purge. The standard deviation on the mean value of energy performance has the average value of 30 kWh/m2 in the categorization for single family housing. For multi-family housing the standard deviation of the mean value is on average 17 kWh/m2 in the categorization. The high value of standard deviation for single family housing is affected by the wide range of energy performances values. These values could be caused by buildings that have had renovations or that other parameters that has not been taken into consideration in this study could have been better in the categorization. Detta projekt syftar att bidra till energikartläggningen av Visbys byggnadsbestånd. Med hjälp av energideklarationsdata kategoriseras byggnadsbeståndet efter definierande energirelaterade parametrar. Ur varje kategori tas en arketypbyggnad fram från medelvärdet av intressanta parametrar inom sin grupp. Målet är att skapa distinkta arketyper som fångar en så stor del av byggnadsbeståndet som möjligt. Studien inleds med en inventering av Visbys byggnadsbestånd för att skapa en helhetsbild, detta stadie benämns i rapporten som lägesöversikt. Därefter undersöks olika kategoriseringar av byggnadsbeståndet utifrån några intressanta parametrar som antas ha inverkan på byggnadernas energiförbrukning. Avsikten är att undersöka vilka parametrar som tillsammans fångar den mest representativa bilden av Visbys byggnadsbestånd. Byggnadernas energiprestanda utgör den huvudsakliga faktorn för jämförelse. Parametrar som undersöks i kategoriseringarna är: Byggnadstyp, läge på byggnaderna, byggnadsvolym, typkod, nybyggnadsår, uppvärmningssystem och antal plan. Ur fastställda kategorier tas sedan arketyper och typbyggnader fram. Studien avgränsas till att endast undersöka bostadsbyggnader. Det använda materialet rensas på abnorma värden vid två tillfällen under studiens gång. Rensningen förhindrar att ett fåtal utstickande värden ger en missvisande bild av byggnadsbeståndets egenskaper. Lägesöversikten leder till 6 undersökta kategoriseringar där två väljs ut: en för flerbostadshus och en för småhus. Parametrar som bäst definierar gruppen småhus är nybyggnadsår, uppvärmningssystem och byggnadsvolym. Parametrar som bäst definierar gruppen flerbostadshus är nybyggnadsår och byggnadsvolym. Den fastställda kategoriseringen täcker 92% av byggnadsbeståndet och totalt stryks 205 byggnader vid rensning. Standardavvikelsen i energiprestanda ligger i snitt på 30 kWh/m2 i kategoriseringen för småhus och i snitt på 17 kWh/m2 i kategoriseringen för flerbostadshus. Den stora spridningen av energiprestanda i gruppen småhus kan till exempel bero på att vissa byggnader blivit renoverade eller att parametrar som bättre definierar gruppen inte har undersökts i denna studie.

Energies : open-access journal of related scientific research, technology development and studies in policy and management 14(24), 8250 (2021). doi:10.3390/en14248250 Published by MDPI, Basel