Search

Heat pumps play a central role in decarbonizing the heat supply of buildings. However, in this article, implementing heat pumps in existing buildings, a significant challenge is still presented due to high temperature requirements. In this article, a systematic analysis of the effects of heat source temperatures, maximum heat pump condenser temperatures, and system temperatures on the seasonal performance of heat pump (HP) systems is presented. The quantitative performance analysis encompasses over 50 heat pumps installed in residential buildings, revealing correlations between the building characteristics, observed temperatures, and heat pump type. The performance of an HP system retrofitted to a 30‐dwelling multifamily building is presented in more detail. The bivalent HP system combines air and ground as heat sources and achieves a seasonal performance factor of 3.25 with a share of the gas boiler of 27% in its first year of operation. In these findings, the technical feasibility of retrofitting heat pumps is demonstrated in existing buildings and insights are provided into overcoming the challenges associated with high temperature requirements. [ABSTRACT FROM AUTHOR]

To gain access to information on energy use in office buildings, the German Federal Ministry for Economy launched an intensive research and demonstration programme in 1995. In advance of the 2002 EU energy performance directive a limited primary energy coefficient of about 100 kW h [m.sup.-2] [a.sup.-1] as a goal for the complete building services technology was postulated (HVAC + lighting) for all demonstration buildings to be supported. A further condition was that active cooling be avoided. Techniques such as natural or mechanical night ventilation or heat removal by slab cooling with vertical ground pipes as well as earth-to-air heat exchangers in the ventilation system were applied. An accompanying research was established to keep track of the results and the lessons learned from about 22 demonstration buildings realized and monitored until the end of 2005. As one outcome this paper summarises the energy performance of a selection of characteristic buildings together with an overview on the summer thermal comfort situations achieved. The research program will proceed during the next five years. Detailed reports and future results may be downloaded from the internet:www.enbaumonitor.de. Keywords: Office buildings; Energy monitoring; Passive cooling; Thermal comfort; User behaviour

Copyright of Bautechnik is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the face of the broad political call for an "energy turnaround", we are currently witnessing three essential trends with regard to energy infrastructure planning, energy generation and storage: from planned production towards fluctuating production on the basis of renewable energy sources, from centralized generation towards decentralized generation and from expensive energy carriers towards cost-free energy carriers. These changes necessitate considerable modifications of the energy infrastructure. Even though most of these modifications are inherently motivated by geospatial questions and challenges, the integration of energy system models and Geographic Information Systems (GIS) is still in its infancy. This paper analyzes the shortcomings of previous approaches in using GIS in renewable energy-related projects, extracts distinct challenges from these previous efforts and, finally, defines a set of core future research avenues for GIS-based energy infrastructure planning with a focus on the use of renewable energy. These future research avenues comprise the availability base data and their "geospatial awareness", the development of a generic and unified data model, the usage of volunteered geographic information (VGI) and crowdsourced data in analysis processes, the integration of 3D building models and 3D data analysis, the incorporation of network topologies into GIS, the harmonization of the heterogeneous views on aggregation issues in the fields of energy and GIS, fine-grained energy demand estimation from freely-available data sources, decentralized storage facility planning, the investigation of GIS-based public participation mechanisms, the transition from purely structural to operational planning, data privacy aspects and, finally, the development of a new dynamic power market design. [ABSTRACT FROM AUTHOR]

Copyright of Bauphysik is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Unsichere Randbedingungen haben einen großen Einfluss auf das Ergebnis von Gebäudesimulationen. Trotzdem werden Unsicherheitsbewertungen und Sensitivitätsanalysen bisher in der Planungspraxis und auch in wissenschaftlichen Untersuchungen selten durchgeführt. In diesem Beitrag wird eine Methodik zur Unsicherheitsbewertung und Sensitivitätsanalyse für thermische Gebäudesimulationen vorgestellt. Diese wird exemplarisch angewendet, um Einsatzmöglichkeiten darzustellen. Potentielle Einsatzgebiete sind Simulationen im Planungsprozess von Gebäuden sowie eine simulationsbasierte Gebäudebetriebsanalyse. Die Anwendung der Methodik kann dazu beitragen, den Planungsprozess und den Gebäudebetrieb zu verbessern. Methodology for uncertainty and sensitivity analysis for building performance simulation. Uncertainties in simulation input have a big influence on building performance simulation results. Nevertheless, uncertainty quantification and sensitivity analysis is not commonly applied in the design practice and also in scientific research. In this paper a methodology for uncertainty quantification and sensitivity analysis is introduced. The methodology is applied to an example case to illustrate possible applications. It can be used within the design stage of buildings as well as for simulation -based building operation analysis. The methodology can improve the design process as well as building operation. [ABSTRACT FROM AUTHOR]

Abstract: A sustainable and environmentally responsible building concept aims at a high workplace comfort, a significantly reduced heating and cooling demand, a high-efficient plant system, and the use of renewable energy sources to condition the built environment. This paper presents a comprehensive analysis of the heating and cooling concepts of 11 low-energy buildings in terms of energy use, efficiency and occupant thermal comfort. All buildings investigated employ environmental energy sources and sinks – such as the ground, ground water, rainwater and the ambient air – in combination with thermo-active building systems. A limited primary energy use of about 100kWhprim/(m2 neta) as a target for the complete building service technology (HVAC and lighting) was postulated for all buildings presented. With respect to this premise, a comprehensive long-term monitoring in high time resolution was carried out for two to five years, with an accompanying commissioning of the building performance. Measurements include the useful heating and cooling energy use, auxiliary energy use for the hydraulic system, as well as end and primary energy use, occupant thermal comfort and local meteorological conditions. A new methodology is proposed for a holistic approach to the evaluation of heating and cooling concepts, which not only considers the occupants thermal comfort, but also the useful energy consumption and the efficiency of the generation, distribution and delivery of heating and cooling energy. [Copyright &y& Elsevier]

Black-box models such as linear regression have proven to be helpful in ongoing building commissioning in many ways. The aim of this work is to improve linear models with change point for fault detection in buildings. Building simulations revealed poor performance of them (R 2 < 0.7) for some low energy buildings. The regression models (RMs) can be considerably improved by introducing the rate of change of the indoor air temperature (ΔTind) as an independent variable. Thus, R2 values were raised by up to 0.5 (e.g. from 0.2 to 0.7, example with the lowest R2). A new training and application process for the RMs revealed further improvements by using a hierarchical agglomerative clustering algorithm to determine different day-types as additional (categorical) variables in the RM. The application of these improved RMs for outlier detection is demonstrated in three buildings. [ABSTRACT FROM AUTHOR]

A new method for assessing the grid interaction of a building’s electricity consumption and generation is presented. It consists of the Grid Support Coefficients GSC abs and GSC rel . GSC abs “weights” the electricity consumption profile with a time-resolved reference quantity which expresses the availability of electricity in the public grid (here: stock electricity price, residual load, cumulative energy consumption or fraction of wind and PV in the electricity mix). GSC rel relates GSC abs to the worst and best achievable values on a scale of −100 to 100 in order to increase the comparability of the results. The new evaluation method is applied to analyze the electricity consumption and/or production of 52 different energy supply systems in buildings, where detailed monitoring data are available. These examples include twelve heat pumps or chillers in office buildings, 38 heat pumps in residential buildings and two combined heat and power units (CHP) in multi-family buildings, all located in Germany. The in-depth analysis shows that the analyzed present-day buildings predominantly consume electricity at times with a low or average electricity availability. Optimal scheduling of all heat pumps could flatten the residual load significantly. In order to achieve this, thermal storages several times larger than the ones currently installed would be required. [ABSTRACT FROM AUTHOR]