Search

Against the background of climate protection and the rising costs of a fossil-fuel-based energy supply, the interest in the energy performance and indoor climate of buildings in real operation is rising. This paper, therefore, deals with the indoor climate investigation of two medium-sized office buildings in Germany by taking measurements over a whole year. These relate to one new building and one refurbished building. Sensors of various types were installed and operated in a large number of office rooms, so that in total results are available for over 100 rooms, typically occupied by one or two persons. The analysis focuses on the indoor temperature in summer and the air quality in winter based on the CO2 concentration. The comfort classes according to DIN EN 16798 including the adaptive comfort approach are used as a basis to cluster the results. Both buildings have movable sun protection and openable windows but no facilities for active cooling. They, thus, represent a large number of existing 'low tech' office buildings in Germany and central Europe. The results reflect the respective building concepts but also show a wide range between the rooms due to the user preferences and behaviour. The refurbished building shows better results, especially in terms of air quality but also in terms of summer room temperatures. This underlines the benefit of the targeted measures as a result of an analysis of the deficits in the existing building before the refurbishment. The additional measures for decentralised mechanical ventilation and passive cooling are having positive effects. As part of the projects, further measures to improve the indoor climate were investigated in both buildings. In one case, this involved CO2 traffic lights to stimulate personal window ventilation in winter, and in the other, the use of newly developed individual ceiling fans supports convective heat dissipation on the human body during hot spells in summer. The positive effect could be demonstrated for both measures. [ABSTRACT FROM AUTHOR]

This research is primarily focused on utilizing available airborne LiDAR data and spatial data from the OpenStreetMap (OSM) database to generate 3D models of buildings for a large-scale urban area. The city center of Ljubljana, Slovenia, was selected for the study area due to data availability and diversity of building shapes, heights, and functions, which presented a challenge for the automated generation of 3D models. To extract building heights, a range of data sources were utilized, including OSM attribute data, as well as georeferenced and classified point clouds and a digital elevation model (DEM) obtained from openly available LiDAR survey data of the Slovenian Environment Agency. A digital surface model (DSM) and digital terrain model (DTM) were derived from the processed LiDAR data. Building outlines and attributes were extracted from OSM and processed using QGIS. Spatial coverage of OSM data for buildings in the study area is excellent, whereas only 18% have attributes describing external appearance of the building and 6% describing roof type. LASTools software (rapidlasso GmbH, Friedrichshafener Straße 1, 82205 Gilching, GERMANY) was used to derive and assign building heights from 3D coordinates of the segmented point clouds. Various software options for procedural modeling were compared and Blender was selected due to the ability to process OSM data, availability of documentation, and low computing requirements. Using procedural modeling, a 3D model with level of detail (LOD) 1 was created fully automated. After analyzing roof types, a 3D model with LOD2 was created fully automated for 87.64% of buildings. For the remaining buildings, a comparison of procedural roof modeling and manual roof editing was performed. Finally, a visual comparison between the resulting 3D model and Google Earth's model was performed. The main objective of this study is to demonstrate the efficient modeling process using open data and free software and resulting in an enhanced accuracy of the 3D building models compared to previous LOD2 iterations. [ABSTRACT FROM AUTHOR]

Political secularism can be defined as a kind of political philosophy that sees the secular state as setting the terms of encounter between the secular and the religious. However, religion and religious organisations are not necessarily seen as oppositional to the secular state; there can be myriad forms of coexistence between secular and religious authorities. The argument forwarded in this article is based on ethnographic research focussing on the presence and social significance of religious materiality in the region considered to be one of the most secularised worldwide—the north-eastern part of contemporary Germany. I investigate the strategies of actors socially recognised as either religious or secular towards each other, looking at how secular actors assign a place to religious symbols, materiality, theological concepts, organisations, and communities; on the other hand I investigate strategies that religious actors adopt in a context of political secularism. Even if political secularism presupposes supremacy of the secular state over religious actors and the right of the former to make legally binding decisions concerning the latter, those religious actors are not passive—they react to secular initiatives and they try to carve for themselves a space in a public sphere, while at the same time the secular or rather nonreligious actors mobilize religious elements for a variety of reasons. [ABSTRACT FROM AUTHOR]

Local Energy Markets (LEMs) were recently proposed as a measure to coordinate an increasing amount of distributed energy resources on a distribution grid level. A variety of market models for LEMs are currently being discussed; however, a consistent analysis of various proposed grid tariff designs is missing. We address this gap by formulating a linear optimization-based market matching algorithm capable of modeling a variation of grid tariff designs. A comprehensive simulative study is performed for yearly simulations of a rural, semiurban, and urban grids in Germany, focusing on electric vehicles, heat pumps, battery storage, and photovoltaics in residential and commercial buildings. We compare energy-based grid tariffs with constant, topology-dependent and time-variable cost components and power-based tariffs to a benchmark case. The results show that grid tariffs with power fees show a significantly higher potential for the reduction of peak demand and feed-in (30–64%) than energy fee-based tariffs (8–49%). Additionally, we show that energy-based grid tariffs do not value the flexibility of assets such as electric vehicles compared to inflexible loads. A postprocessing of market results valuing the reduction of power peaks is proposed, enabling a compensation for the usage of asset flexibility. [ABSTRACT FROM AUTHOR]

Unrenovated multifamily houses in Germany are mostly heated by fossil heat generators; therefore, measures are required for CO2 emission reduction. The use of air–water heat pumps is restricted by high required flow temperatures and heat output but can be mitigated by hybrid heat pumps. To limit additional operation costs by the heat pump, a new operation strategy is introduced in this study, which allows to maintain a target CO2 emission. The operation strategy is applied in a field trial in a small unrenovated multifamily house built in 1964. A thermohydraulic simulation model is verified and is used in full-year simulations to apply improvement measures and compare the new control strategy with existing optimizing strategies. The results show that the control onto target emissions is possible and limits additional costs but can also result in higher CO2 mitigation costs, making it less favorable. The hybrid heat pump reduces the direct fossil CO2 emissions by 61% (in total by 22%); thus, it is a relevant solution for multifamily houses, especially within a further decarbonized electrical grid. [ABSTRACT FROM AUTHOR]

Due to financial or administrative constraints, access to official spatial base data is currently limited to a small subset of all potential users in the field of spatial planning and research. This increases the usefulness of Volunteered Geographic Information (VGI), in particular OpenStreetMap (OSM), as supplementary datasets or, in some cases, alternative sources of primary data. In contrast to the OSM street network, which has already been thoroughly investigated and found to be practically complete in many areas, the degree of completeness of OSM data on buildings is still unclear. In this paper we describe methods to analyze building completeness and apply these to various test areas in Germany. Official data from national mapping and cadastral agencies is used as a basis for comparison. The results show that unit-based completeness measurements (e.g., total number or area of buildings) are highly sensitive to disparities in modeling between official data and VGI. Therefore, we recommend object-based methods to study the completeness of OSM building footprint data. An analysis from November 2011 in Germany indicated a completeness of 25% in the federal states of North Rhine-Westphalia and 15% in Saxony. Although further analyses from 2012 confirm that data completeness in Saxony has risen to 23%, the rate of new data input was slowing in the year 2012. OPEN ACCESS [ABSTRACT FROM AUTHOR]

While it is widely acknowledged that carbon pricing plays an important role in driving the transition towards a low-carbon energy system, its interaction with complementary instruments is discussed controversially. The analysis of combining carbon pricing with complementary policies has been mostly focused on the electricity sector, while the role of carbon pricing in the buildings sector has received only minor interest. In view of the newly introduced carbon pricing scheme for the buildings and transport sector in Germany, we analyze the interactions between the carbon pricing scheme with the existing policy instruments and assess the consistency of the policy mix for decarbonizing the buildings sector. Our analysis finds that the introduction of carbon pricing has a reinforcing effect on the instrument mix and adds to the consistency of the policy mix. The results highlight the importance of complementary policies in order to achieve deep decarbonization in the buildings sector. We conclude that carbon pricing, preferably implemented as a tax with a predictable and increasing price level, needs to be supplemented with a powerful mix of complementary measures. [ABSTRACT FROM AUTHOR]

The integration of photovoltaic (PV) generators in the envelope of a building by means of building-integrated photovoltaics (BIPV) offers an immense potential, both in market development and the production of renewable electric energy that is close to the point of electricity consumption. In Germany, for example, by integrating photovoltaics in buildings up to 50% of the electricity demand can be covered. The political support of BIPV would contribute to the development and installation of BIPV components and therefore also promote the development of new business areas for industries dealing with components used in building envelopes and photovoltaic generators. BIPV can be separated into three different integration types: "technical", "formal" and "technical & formal". Political instruments for the support of PV-installations, particularly BIPV are discussed in this paper using Germany and France as examples. Due to successful financial support policies, PV became the most powerful electricity production technology in Germany. In France, the unique financial support of BIPV is resulting in an exemplary development and growth of certified BIPV components available on the market and, from a technical, aesthetic architectural and legal certainty point of view, facilitating the easy and widespread integration of photovoltaic generators in buildings. [ABSTRACT FROM AUTHOR]

Cement manufacturing is an emission-intensive process. The cement industry is responsible for 8% of the global CO2 emissions, and produces a ton of cement uses up to 102 kWh of electrical energy, leading to a significant amount of indirect emissions depending on the emission intensity of the electricity source. Captive power generation can be potentially utilised as a mitigation approach to reduce emissions and as well as expenditure on electricity tariffs. In this study, a system dynamic simulation model is built to evaluate the impact of captive power generation on a cement plant's net emissions and expenditure through electricity use, under different scenarios for carbon-tax, grid emission factor, and electricity tariffs. The model is then utilised to simulate a reference plant under realistic scenarios designed based on the conditions in Germany and United Arab Emirates. Furthermore, the model is utilised to calculate the payback period of investments on captive power plants under different carbon tax scenarios. The study concludes that a carbon tax policy on emissions through electricity utilisation could have an impact on incentivising the use of captive power generation and would lead to fewer emissions and expenditure during the cement plant's lifetime. [ABSTRACT FROM AUTHOR]

Demand response has been noted as a major element of future smart energy systems. However, there is still a lack of knowledge about the demand response actions in different conditions—including climate, dynamic energy price, and building types. This study examines energy and cost saving potential of the rule-based demand response in district heating network, in three different building types, in Germany and Finland. The studied building types are apartment buildings, cultural centers, and office buildings. The real-time pricing-based demand response is applied to space heating under the climate conditions of Helsinki, Finland and Hamburg, Germany. Moreover, the typical synthetic dynamic price data, which are based on both counties' district heating production structure, is applied separately for each countries' cases. Simulations of this study are conducted with validated simulation tool IDA ICE. The results present that the demand response can provide energy and cost savings around 0.5–7.7% and 0.7–8.1% respectively, depending on the building type and country. The results indicate that marginal value of the control signal, climate conditions, and the dynamic price of the district heating have effect on the demand response saving potential. Flatter district heating price profile provides less savings than a more fluctuating profile. [ABSTRACT FROM AUTHOR]

In the literature, optimization-based approaches are frequently proposed for the control of electric vehicle charging. However, they are usually evaluated under simplifying assumptions and are not compared to more simple approaches. The present work compares optimization-based approaches with rule-based ones in a simple but realistic scenario, in which a certain limit for the total load has to be satisfied. The scenario is based on the situation at an office building in Germany. In simulation experiments, different control approaches are evaluated not only in terms of pure performance but also from an economic perspective. The results indicate that, although the optimization-based approaches outperform the rule-based approaches, they are not always the right choice from an economic point of view. [ABSTRACT FROM AUTHOR]

Long-term studies of ground source heat pump (GSHP) heating and cooling systems for six different buildings (commercial, institutional and multi-family buildings) were conducted in Germany by Steinbeis-Innovationszentrum (SIZ) energy+. Three of them are equipped with borehole heat exchangers, and the others use energy piles as heat exchangers. This paper deals with a demonstration of the investigated buildings, the measured values and performance, and the obtained results include important findings and experiences, problems encountered and possible preventive measures to avoid mistakes. After ten years of operation, it can be stated that the systems work and achieve their planned efficiency but require constant control and regulation to avoid faulty operation. An analysis of the implemented control strategies shows that, for all these heating and cooling systems, holistically coordinated control strategies that are verified during commissioning are required. [ABSTRACT FROM AUTHOR]

The present paper introduces an iterative methodology to progressively reduce building simulation model complexity with the aim of identifying potential trade-offs between computational requirements (i.e., model complexity) and energy estimation accuracy. Different levels of model complexity are analysed, from commercial building energy simulation tools to low order calibrated thermal networks models. Experimental data from a residential building in Germany were collected and used to validate two detailed white-box models and a simplified white-box model. The validation process was performed in terms of internal temperature profiles and building thermal energy demand predictions. Synthetic profiles were generated from the validated models and used for calibrating high order models. A reduction (trimming) procedure was applied to reduce the model complexity using an energy performance criterion prior to model trimming. The proposed methodology has the advantage of keeping the physical structure of the original RC model, thus enabling the use of the trimmed lumped parameter building model for other applications. The analysis showed that it is possible to reduce the model complexity by half, while keeping the accuracy above 90% for the targeted building. [ABSTRACT FROM AUTHOR]

Existing private homes in Germany and throughout Europe often are in need of energy efficient refurbishment measures (EERMs). However, these EERMs are not realized on the required level in order to achieve environment-related political targets. Therefore we investigate, based on an online survey of 1085 German owner-occupiers, the factors that differentiate two groups of single- and two-family house owners in need of EERM. Using an extended version of the Theory of Planned Behavior as a research framework, the performed logistic regression analysis shows that e.g., behavioral beliefs are significant factors for differentiating "Future-Refurbishers" from "Non-Refurbishers". Based on our results we suggest an enhancement of practice-orientated initiatives, e.g., refurbishment workshops or best-practice presentations. By presenting the aesthetic appearance of refurbished buildings or providing knowledge, other owner-occupiers could be motivated to engage in EERM. In addition to funding programs, initiatives like this can be used to increase the general energy efficiency of buildings and specifically of those in cities and urban districts, where a high share of the mentioned houses is located and greenhouse gas emissions are caused to a great extent. [ABSTRACT FROM AUTHOR]