Geissler, Achim

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Geissler
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Achim
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Geissler, Achim

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2013 - 201992020 - 20237
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Typ: 01A - Beitrag in wissenschaftlicher Zeitschrift ×

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  • Vorschaubild
    Publikation
    Gravity ventilation for interior bathrooms
    (IOP Publishing, 01.12.2023) Hall, Monika; Gerber, Vincent; Geissler, Achim [in: Journal of Physics: Conference Series]
    Based on the extensive experience of a building cooperative with interior bathroom gravity (shaft) ventilation in existing apartment buildings, the replacement buildings constructed at the same location are also equipped with gravity ventilation. The aim of the project described here is to demonstrate the possibilities and limitations of gravity ventilation in one of the new replacement buildings by means of monitoring. Detailed monitoring over a complete year recorded the behaviour and effectiveness of the gravity ventilation in all seasons. In winter, gravity ventilation leads to higher air change rates in interior bathrooms than in summer. In general, humidity can be removed with gravity ventilation except in summer, when after a shower the bathroom door stays closed for 24 h. In summer when the indoor and ambient temperature is the same the gravity ventilation does not work. In this case, the interior bathroom should be ventilated by the main apartment ventilation, e.g., while the bathroom door and other room doors and windows are open at the same time. In summer, doors and windows are often open and the gravity ventilation summer problem can be viewed as negligible. Therefore, gravity ventilation is a good alternative to other ventilation systems in interior bathrooms.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Determine the heat demand of existing buildings with machine learning
    (IOP Publishing, 01.12.2023) Hofmann, Joachim Werner; Amoser, Christian; Geissler, Achim; Hall, Monika [in: Journal of Physics: Conference Series]
    The renovation rate of existing buildings plays a major role in the Swiss Energy Strategy 2050+. To increase this rate, there must be a simple and cost-effective method to determine the heat demand of existing buildings. In this paper, the generation of such a method, based on the Swiss cantonal building energy certificate (GEAK) database with the help of machine learning (ML), is studied. The aim of the project was to develop a ML model which allows the heat demand of existing buildings to be determined quickly with a minimal set of parameters. The comparison of the GEAK building envelope class for single family houses calculated with the new ML model and the original GEAK classes shows that approximately 62 % have the same class, 32 % differ by one class and 6 % by two classes. The ML model is a good starting point for further refinements and developments.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Development of a Multi-Criteria Decision-Making model to assist building designers in the choice of superficial construction systems in urban areas
    (SAGE, 22.12.2022) Dürr, Jonas; Geissler, Achim; Hoffmann, Caroline [in: Journal of Building Physics]
    An enormous range of building materials that is almost impossible to keep track of is available. The trend toward building densification in cities continues apace. Coupled with climate change, a situation is emerging that poses ecological as well as economic risks in terms of living comfort in public, urban spaces. Building designers need help (tools) to be able to address a wide range of requirements within their planning. The development of the Multi-Criteria Decision-Making (MCDM) model BASK (engl. “Construction Materials for Cities in Climate Change”) is presented. The goal of the model is to assist building designers in determining surface materials for wall, ground and roof construction and help determine the best compromise between environmental, economic, and building practice criteria. Currently available criteria are heat stress, visual reflectance, CO equivalents, electricity production, retrofitability, sound absorption, construction costs, and life span. The criteria can be weighted by the designer, resulting in a customized ranking of construction systems that best meets the designer’s prioritized criteria. The design of BASK basically allows for an extension of the criteria. The version of BASK described in this paper includes 10 construction systems covering a wide range of construction types focused on walls. The tool requires technical data for materials considered in construction systems included, which are made available via a data base. The scope of construction systems can also be extended in the future. Based on the restricted set of construction systems the results of a sensitivity analysis and initial validation are given.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Comparison of flexibility factors and introduction of a flexibility classification using advanced heat pump control
    (MDPI, 13.12.2021) Hall, Monika; Geissler, Achim [in: Energies]
    With the increasing use of renewable energy, the energy flexibility of buildings becomes increasingly important regarding grid support. Therefore, there is a need to describe this flexibility in a concise manner. For the characterization of building energy flexibility, flexibility factors can be used. The comparison of a selection of existing flexibility factors shows that they are not easy to use or understand for designers and users. A simplification is necessary. The aim of this study is to introduce a flexibility classification that is easy to understand and shows in an easy way if a building already uses the lowest energy cost level or if further improvement is possible. The classification expresses the annual energy costs in colored classes: green (class A) for lowest up to red (class D) for highest level. Basically, the flexibility classes can be derived for any metric of interest, in this paper examples are shown for energy costs and CO2eq emissions. The results given are based on the simulation of load management scenarios with different penalty signals applied for the heat pump operation of a residential building.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Comparison of flexibility factors for a residential building
    (IOP Publishing, 18.11.2021) Hall, Monika; Geissler, Achim [in: Journal of Physics: Conference Series]
    Buildings that are able to shift their loads without comfort restraints are important for the ongoing transformation of the power supply. This flexibility potential can be expressed in flexibility factors. The usefulness of four factors is investigated based on load control for the heat pump of a small apartment building according to electricity prices (high/low tariffs, spot market prices), CO2eq emissions share in the grid and a restricted operation period during daytime. The calculation methodology of the presented flexibility factors GSC, RIP, FF and FI is very different. RIP and FF are preferable because they have defined valid ranges which makes them easier to understand. Current electricity prices force the heat pump operation mainly into the night. The optimization of CO2eq emissions encourages operation mainly during the day. The optimization goals costs or CO2eq emissions thus lead to opposing heat pump operation times and can currently therefore not both be met simultaneously.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Passive window ventilation openings in every-day use
    (Elsevier, 28.08.2021) Hoffmann, Caroline; Geissler, Achim; Hauri, Claudia; Huber, Heinrich [in: Building and Environment]
    The integration of passive window ventilation openings (PWVO, small air inlets integrated in the window frame) with additional exhaust fans in the kitchen and bathroom(s) can ensure a user-independent basic air change rate in dwellings. The project reported on herein is focused on how well buildings with PWVO work in real life.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Load Control by Demand Side Management to Support Grid Stability in Building Clusters
    (MDPI, 01.10.2020) Hall, Monika; Geissler, Achim [in: Energies]
    Increasing numbers of photovoltaic systems and heat pumps in existing building clusters can lead to an overload of the associated substations of the electric grid. Based on a multi-agent-based simulation of three building cluster types the impact of building flexibility in regard to the residual substation load is studied. Each building announces its available flexibility, e.g. “heat pump can be switched off/on”. A cluster master coordinator evaluates the incoming offers and decides which offers are accepted in regard to the substation’s capacity utilization. The goal is to honour the substation’s limit by shifting the residual load. This paper presents results from three typical urban building clusters for different penetration scenarios in regard to heat pumps, photovoltaic systems, batteries and electric vehicles. It is shown that in the studied building clusters a high penetration of heat pumps and photovoltaic systems can violate the existing substation’s limits, regardless of the efforts by the master coordinator. Batteries of typical capacities cannot reduce the peak residual load. The load shifting options of the master coordinator are limited.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Multi-agent based simulation of smart building cluster for electric grid stabilization
    (IOP Publishing, 21.11.2019) Hall, Monika; Geissler, Achim; Wache, Holger [in: Journal of Physics: Conference Series]
    With the increasing number of photovoltaic systems and heat pumps in buildings existing substations of the electric grid could be overloaded. A multi-agent based simulation of a building cluster studies the impact of building flexibility in regard to the residual substation load. Each building announces its available flexibility, e.g. "heat pump can be switched off/on". A master coordinator evaluates all incoming offers and decides which offers are accepted. This reduces the residual load at the substation. This paper presents results from a study of the impact at the substation of a smart urban building cluster with different penetration scenarios of heat pumps, photovoltaic systems, batteries and electric vehicles. It is shown that a high penetration of heat pumps and photovoltaic systems violates the substation's limits for the studied building cluster. Batteries cannot reduce the peak utilization. The master coordinator's load shifting options are limited.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Conversion of unheated basements and the conditioning of their indoor climate
    (IOP Publishing, 2019) Hoffmann, Caroline; Geissler, Achim; Huber, Heinrich; Hauri, Claudia [in: Journal of Physics: Conference Series]
    This paper deals with unheated basements in existing buildings. Due to soaring housing prices these rooms may be increasingly used for the storage of sensitive goods and temporarily for leisure activities. In order to keep these rooms free of mould various technical solutions are available. However, it is unclear whether they prevent mould growth and how high their energy demand is. This question is explored by simulating an unheated basement in an uninsulated, a renovated and a newly built building. The paper considers and evalueates four different operation modes for the basement.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    The prebound-effect in detail: real indoor temperatures in basements and measured versus calculated U-values
    (Elsevier, 12.09.2017) Hoffmann, Caroline; Geissler, Achim [in: Energy Procedia]
    This paper focuses on the topics U-values and indoor air temperatures of unheated basements with uninsulated cellar ceilings. Measurement values are compared with calculation procedures suggested by building regulations. Concerning the U-values it is shown that they are typically considered to be higher (i.e. worse) in uninsulated existing constructions than they effectively are. Measured temperatures in seven basements are higher (around 8 K) than a calculation according to regulations would yield. The paper derives suggestions for the adjustment of calculations focused on existing residential buildings.
    01A - Beitrag in wissenschaftlicher Zeitschrift