Hall, Monika
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Monika
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Hall, Monika
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- PublikationGravity 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
- PublikationDetermine 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
- PublikationEinfluss der Luftdichtheit auf den Heizwärme‐ und Klimakältebedarf bei neuen Einfamilienhäusern(Ernst & Sohn, 06.04.2023) Hall, Monika [in: Bauphysik]Die Luftdichtheit von Gebäuden hat einen Einfluss auf den Lüftungswärmestrom und damit auf den Heizwärme- und Klimakältebedarf. Der unkontrollierte Luftstrom durch Leckagen gewinnt mit zunehmendem Dämmniveau an Bedeutung. Um den Einfluss der Luftdichtheit bei hohem Dämmstandard auf den Heizwärme- und Klimakältebedarf zu untersuchen, werden verschiedene Szenarien mit einer thermischen Gebäudesimulation betrachtet. Zusätzlich werden an 28 neuen Einfamilienhäusern Luftdichtheitstests durchgeführt, um die Luftdichtheit von Standardneubauten zu bestimmen. Die Simulationen bestätigen, dass der Heizwärme- und Klimakältebedarf mit zunehmender Undichtheit zunimmt. Infolge der großen Temperaturdifferenz zwischen innen und außen sowie höheren Windgeschwindigkeiten im Winter ist der Einfluss der Luftdichtheit auf den Heizwärmebedarf größer als auf den Klimakältebedarf im Sommer. Die ermittelte Luftdichtheit der gemessenen Gebäude weist im Mittel ein q50 = 0,8 m3/(h · m2) auf, was ein sehr guter Luftdichtheitswert ist. Ihr Heizwärmebedarf wird sich durch die Undichtheiten voraussichtlich um ca. 3 % bis 6 % gegenüber einem dichten Gebäude mit q50 = 0,6 m3/(h · m2) erhöhen. Der Klimakältebedarf wird sich um ca. 1 % bis 2 % reduzieren.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationPotential-estimation of thermal micro-grids in urban areas based on heat load and building clustering(IOP Publishing, 2023) Hall, Monika; Bereuter, Pia; Geissler, Achim [in: Journal of Physics: Conference Series]As a result of climate change, fossil heating systems must be replaced with renewable systems. The question arises whether it makes sense for each building to have its own new heating system or whether a thermal micro-grid is possible. In this paper a model is presented which allows to aggregate buildings into thermal micro-grid clusters. All gas-heated residential buildings of Basel (Switzerland) are marked via geo-data. The heat demand of each building is determined depending on the year of construction and is then converted into the heat load. Each building then is grouped into thermal micro-grids according to a given grid load limit. The thermal micro-grids generated in this way are marked in color, so that the potential of any given city district can be easily and quickly identified. If the grid load limit is increased, the number of possible micro-grids increases, also.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationComparison 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
- PublikationComparison 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
- PublikationLoad 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
- PublikationMulti-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
- PublikationPVopti - hourly based energy balance for building design(Elsevier, 2017) Hall, Monika; Burger, Bastian [in: Energy Procedia]PVopti is a freeware tool to calculate hourly energy balance for different building types. It is simple to use and it quickly calculates self-consumption for different designs. Load profiles according to SIA 2024 are used to distribute yearly values on hours. For demand of lighting a criterion for daylight is added. Compared with measurements of single family houses and apartment buildings, self-consumption calculated with PVopti shows very good agreement. Currently, a German version is available on www.minergie.ch, soon there will be versions for 4 languages (dt, fr, it, en).01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationDifferent balancing methods for Net Zero Energy Buildings - Impact of time steps, grid interaction and weighting factors(Elsevier, 2017) Hall, Monika; Geissler, Achim [in: Energy Procedia]Adding large photovoltaic systems to buildings is becoming more and more popular. To date, the self-consumption/grid interaction is not typically part of the energy balance. The choice of symmetric or asymmetric primary energy factors has an impact on the balance. The primary energy factor for import from the grid depends on the chosen type of the power mix in the grid. If this factor is higher/lower than the primary energy factor of the on-site PV-system, a larger/smaller PV system than when using symmetrical factors is required in order to fulfil the NZEB balance.01A - Beitrag in wissenschaftlicher Zeitschrift