TY - CHAP A1 - Hummel, Sebastian A1 - Betzold, Christina A1 - Dentel, Arno T1 - Impact of the Weather Forecast Quality on a MPCdriven Heat Pump Heating System BT - REHVA 14th HVAC World Congress, 22nd-25th May, Rotterdam, The Netherlands T2 - CLIMA 2022 N2 - Electrically driven heat pumps offer in combination with thermal energy storage systems the potential to response to fluctuating renewable energy sources, e.g. photovoltaics. To fully exploit this flexibility and financial potential, smart predictive control strategies such as Model Predictive Control (MPC) are needed. For such a controller, weather forecast data are mandatory to perform the optimization. Several sources of weather forecast data are available with variable forecasting quality. In this study, the impact of the weather forecast quality on a realistic heat pump heating system is investigated in experiments and simulations. Therefore, the operation of a MPC strategy is carried out for a perfect forecast compared to two imperfect forecast scenarios over a consecutive period of 4 days on a Hardware-in-the-Loop test bench with a geothermal heat pump and a thermal energy storage system. In order to evaluate the benefits in real operation compared to rule-based controllers, a heat-controlled (HC) and a PV self-consumption optimized controller (PVC) are also operated on the test bench. In addition and as a validation process, all scenarios are simulated and compared to the measurement results. Compared to a standard rule-based HC strategy the PV self-consumption can be increased by using a PVC and MPC strategy by 6.2 % and 38.9 %, respectively. The accurately the weather forecasting quality is in general the higher the performance of the HP heating system. Thus, the PV self-consumption is reduced for high-quality and low-quality weather forecasts by 4.6 % and 11.1 %, respectively, compared to a perfect MPC. Even a MPC with low-quality weather forecast data can achieve higher system performance as a simple rule-based HC strategy. For achieving higher system performance by using a MPC instead of a rule-based control strategy like PVC the, forecasting quality has to be as accurate as possible. KW - model predictive control KW - weather forecast KW - self-consumption KW - experimental study Y1 - 2022 UR - https://doi.org/10.34641/clima.2022.152 ER - TY - CHAP A1 - Dentel, Arno A1 - Betzold, Christina T1 - Activation of the building thermal mass to store PV surplus energy T2 - Proceedings of the 17th IBPSA Conference : Bruges, Belgium, Sept. 1-3, 2021 Y1 - 2021 U6 - https://doi.org/10.26868/25222708.2021.31141 SN - 2522-2708 SP - 673 EP - 679 PB - KU Leuven ER - TY - JOUR A1 - Betzold, Christina A1 - Dentel, Arno T1 - Smart integration of heat pumps by predictive controls JF - Heat Pumping Technologies Magazine N2 - The integration of heat pumps into a PV and battery system faces the challenge of sharing the available PV power among the actors. In order to coordinate this competition, a suitable energy concept, as well as the control, must match. In a cluster of eight terraced houses, an energy system has been implemented, which should represent a smart integration of heat pumps. To coordinate the interaction of the components, model predictive controls are used. The simulation shows very good results for the predictive controls, but the results cannot be replicated in total practice. Y1 - 2022 U6 - https://doi.org/10.23697/7mmf-3f37 VL - 40 IS - 3 SP - 25 EP - 27 ER - TY - CHAP A1 - Betzold, Christina A1 - Dentel, Arno T1 - Evaluation and test operation of different model predictive control approaches for an energy system T2 - Proceedings of the 17th IBPSA Conference : Bruges, Belgium, Sept. 1-3, 2021 KW - MPC, modelling approaches, optimization approaches Y1 - 2021 U6 - https://doi.org/10.26868/25222708.2021.30597 SN - 2522-2708 SP - 326 EP - 333 PB - KU Leuven ER - TY - CHAP A1 - Betzold, Christina A1 - Dentel, Arno T1 - Comparison and implementation of MPC and simple predictive control into a heat pump system BT - REHVA 14th HVAC World Congress, 22nd-25th May, Rotterdam, The Netherlands T2 - CLIMA 2022 N2 - Heat pumps in combination with thermal energy storage systems offer the potential to response to fluctuating renewable energy sources, e.g. photovoltaics. To fully exploit this flexibility and financial potential, predictive control strategies are needed. Since an additional effort due to detailed knowledge and programming skills is required to create the model predictive control (MPC) strategies, a fast and easy implementation is prevented. Therefore, a second model-based approach is developed with a predictive but rule-based control. This simplified approach uses predictive models as well but energy balancing to determine the heat pump operation and the state of charge of thermal storage units throughout the day. In this paper, two predictive approaches were compared with two rule-based controls and evaluated for their potential for PV self-consumption and cost savings in annual simulations. In addition, one rule-based PV optimized control (PVC) and the predictive approaches, MPC and the simple predictive control (SPC), are implemented in the real operation in a plus energy building. In simulation, the best result is achieved by the MPC with a cost saving of 8.3 % due to a high PV energy consumption but mainly to the best efficiency with a SPF of 4.5. Despite the predictive approach of SPC, SPC and PVC achieve very similar results with cost savings of 2.5 % and 0.8 %. Since the costs of PV include taxes, these moderate cost savings are achieved. Excluding these taxes, there are significantly higher cost savings of up to 34 % for MPC. In real operation, differences between simulation results and measured data become apparent. This gap between the set point output of the simulation and the set point input of the real components poses a challenge to the implementation of efficient and cost-effective control like the MPC. KW - MPC KW - simple predictive control KW - PV self-consumption KW - operating costs Y1 - 2022 U6 - https://doi.org/10.34641/clima.2022.154 ER - TY - CHAP A1 - Dentel, Arno A1 - Betzold, Christina T1 - Activation of the building thermal mass to store PV surplus energy T2 - Building Simulation Conference Proceedings N2 - Since 2018, a terraced house complex with shared energy system is monitored and evaluated regarding PV selfconsumption and efficiency (Figure 3). Beside heat pumps and photovoltaics (PV), different kind of storage units are integrated and used to store PV surplus. Thermal storage units for heating and domestic hot water as well as an electrical storage are integrated into the higher-level control system and are charged selectively. However, since the capacity limits have been reached, additional storage options are interesting. The thermal mass of the building offers additional potential to store PV surplus energy. This paper evaluates the operation of thermal mass activation for the terraced house complex in order to increase the PV self-consumption and decrease the grid consumption. The simulation study of thermal mass activation is realized in TRNSYS. Increasing the room set point temperature of 20 °C by 2 K during PV production, aims to a reduction of the grid consumption by 47 % and an increase of PV self-sufficiency from 23 % up to 64 %. At the same time, the mean deviation of the room set temperature increased from 1.7 K to 2.0 K. The results are compared to real measured data from the terraced house. KW - ZEB KW - thermal storage KW - building mass KW - model predictive control Y1 - 2021 U6 - https://doi.org/10.26868/25222708.2021.31141 SN - 2522-2708 SP - 673 EP - 679 PB - KU Leuven ER - TY - CHAP A1 - Betzold, Christina A1 - Dentel, Arno T1 - Evaluation and test operation of different model predictive control approaches for an energy system T2 - Building Simulation Conference Proceedings N2 - The increasing number of predictive model control (MPC) approaches enables a wide variety of designs. However, the question arises which approach is suitable for real operation. This paper examines two different MPC approaches based on simple and detailed models as well as using different optimization algorithms. The MPC approaches are applied and evaluated in a real energy system controlling heat pumps of variable and constant compressor speed. Due to the different characteristics, two implementation processes are required. Both approaches ensure correct system operation, even if the GA approach had to be corrected four times by rule-based intervention. The power control of the MHPs could not be strictly implemented by any approach. KW - MPC KW - modelling approaches KW - optimization approaches Y1 - 2021 U6 - https://doi.org/10.26868/25222708.2021.30597 SN - 2522-2708 SP - 326 EP - 333 PB - KU Leuven ER - TY - CHAP A1 - Betzold, Christina A1 - Bordin, Susanna A1 - Dentel, Arno A1 - Harhausen, Gunnar T1 - Control strategies for modulating heat pumps in a plus energy building T2 - 13th IEA Heat Pump Conference 2021 N2 - Since the feed-in tariff of photovoltaics (PV) decreases [1], PV selfconsumption becomes more profitable. Especially heat pumps, which are able to modulate the compressor speed, open up more flexibility for consuming fluctuating PV power. For exploiting the full potential of PV self-consumption smart control strategies for modulating heat pumps (MHPs) are needed. In this research, the development and the real application of optimized control strategies for MHPs in plus energy terraced houses, built in 2017, are realized. Two control strategies, a PV rule based (PVC) and a model predictive control (MPC) are tested and compared in simulation. Results for the MPC of a 12 months simulation show potential for a moderate increasing PV self-consumption up to 2.1 % and significant reducing operating costs up to 36.1 %. In real application in the terraced houses, the PVC offers an increase of PV self-consumption by 4.1 % for a monitored week, compared to a heat controlled operation. KW - PV self-consumption KW - operating costs KW - modulating heat pumps KW - control strategies Y1 - 2021 SN - 9789189385481 SP - 246 EP - 254 ER - TY - RPRT A1 - Bordin, Susanna A1 - Dentel, Arno A1 - Hummel, Sebastian A1 - Griener, Jonathan A1 - Betzold, Christina A1 - Lorenz, Tim T1 - Untersuchung von Lüftungskonzepten in Schulen : Einfluss auf Raumluftqualität, thermischen Komfort und Gesundheit in Praxis und Simulation BT - Teilprojekte: MoSimEx-Luft (22.33), Technische Hochschule Nürnberg Georg Simon Ohm ; Opti-Luft (22.32), Wolf GmbH N2 - Gute Luft und ein angenehmes Raumklima in Klassenräumen können die Leistungsfähigkeit, das Wohlbefinden und die Gesundheit von Schülerinnen und Schülern sowie Lehrkräften fördern. Die Covid-19-Pandemie hat dabei deutlich gemacht, wie wichtig eine gute Belüftung von Innenräumen ist, um ein Ansteckungsrisiko von über die Luft übertragbaren Infektionen zu senken. Dennoch zeigen aktuelle Studien, dass die Luftqualität in vielen Schulen häufig noch unzureichend ist. Wenn keine maschinellen Lüftungsanlagen vorhanden sind, ist regelmäßiges Lüften über die Fenster im Klassenraum unverzichtbar. Das lässt sich im Schulalltag jedoch oft nur schwer konsequent umsetzen – vor allem dann, wenn draußen sehr kalte oder sehr warme Temperaturen herrschen, was den thermischen Komfort im Raum stark beeinträchtigen kann. Maschinelle Lüftungsanlagen bieten gegenüber der Fensterlüftung den großen Vorteil einer kontrollierten Frischluftzufuhr – unabhängig von den Umgebungsbedingungen (wie z.°B. Außentemperatur, Wind, Lärm) und vom Nutzerverhalten. In der Anwendung können jedoch Fehler auftreten. Neben Komfort- und gesundheitlichen Aspekten sollte auch darauf geachtet werden, Lüftungskonzepte möglichst energieeffizient umzusetzen. Hier knüpft das interdisziplinäre Forschungsprojekt der TH Nürnberg und der Wolf GmbH mit Unterstützung der Paracelsus Medizinischen Privatuniversität Salzburg an. Es untersucht folgende primäre Fragestellungen: • Wie kann eine gute und gesunde Raumluft in Klassenräumen erreicht werden? • Wie kann ein möglichst energieeffizienter Betrieb von Lüftungsanlagen gewährleistet werden? • Welche Potenziale und Fehlerquellen können in der Praxis auftreten? Der Schwerpunkt liegt auf der Anwendung dezentraler Lüftungstechnik mit Außenluftwechsel, da diese gut für die Nachrüstung von Räumen in Bildungseinrichtungen geeignet ist. Für eine ganzheitliche Betrachtung werden eine zentrale raumlufttechnische Anlage und eine reine Fensterlüftung in Kombination mit CO2-Ampeln in die Untersuchungen eingeschlossen. Es wird der Einfluss auf physikalische Parameter auf der einen Seite und den Menschen auf der anderen Seite analysiert. Dabei werden die Aspekte Raumluftqualität, thermischer Komfort, Gesundheit und Energie betrachtet. Zur umfassenden Bewertung von Lüftungsstrategien verbindet das Projekt Simulationsstudien und eine empirische Feldstudie. In einer siebenmonatigen, kontrollierten Beobachtungsstudie wurden drei Lüftungskonzepte in der Praxis an drei Grundschulen über die Winterinfektionssaison 2023/24 detailliert untersucht: • Reine Fensterlüftung in Kombination mit CO2-Ampeln • Maschinelle Lüftung über dezentrale Lüftungsgeräte • Maschinelle Lüftung über eine zentrale Lüftungsanlage Im Rahmen eines umfangreichen Langzeit-Monitorings wurden Parameter zur Luftqualität und des thermischen Raumklimas sowie Fensteröffnungszustände in acht Klassenräumen und Wetterdaten an den drei Schulstandorten erfasst. Während der Studie kamen Fragebögen zu Raumkomfort und Wohlbefinden der Schulkinder sowie zu Erkältungssymptomen zum Einsatz. Ergänzend wurden Speichelproben der Schulkinder auf Infektionsparameter ausgewertet. Forschungsbericht (10.08.18.7- 22.32 & 22.33) 8 In numerischen Strömungssimulationen wurden Lüftungskonzepte für ein dezentrales Lüftungsgerät untersucht. Zusätzlich wurden Jahressimulationen sechs verschiedener Lüftungskonzepte in einer gekoppelten thermisch-energetischen Gebäudesimulation durchgeführt. Auf Basis der Ergebnisse aus Simulation und Feldstudie wurden praxisnahe Handlungsempfehlungen für gute und effiziente Lüftungskonzepte für Schulen formuliert und potenzielle Fehlerquellen im Umgang mit maschinellen Lüftungsanlagen identifiziert. Fachgerecht geplante und gut betriebene Lüftungstechnik – idealerweise mit Wärmerückgewinnung und bedarfsabhängiger Regelung – kann dazu beitragen, eine hohe Raumluftqualität in Klassenräumen zu gewährleisten, das Infektionsrisiko zu senken, den thermischen Komfort zu erhalten und Energie einzusparen. N2 - Good indoor air quality and a comfortable indoor climate in classrooms can promote the performance, well-being, and health of students and teachers. The Covid-19 pandemic has clearly demonstrated how important proper ventilation of indoor spaces is to reduce the risk of airborne infections. However, recent studies show that indoor air quality in many schools is still frequently inadequate. Where no mechanical ventilation systems are in place, regular window ventilation is essential. In everyday school life, however, consistent implementation is often difficult – especially during very cold or hot weather, which can significantly compromise thermal comfort. Mechanical ventilation systems offer a major advantage over window ventilation by enabling controlled fresh air supply, independent of environmental conditions (such as outdoor temperature, wind, or noise) and user behavior. However, errors in operation can occur. In addition to health and comfort aspects, energy efficiency must also be considered when implementing ventilation strategies. This is where the interdisciplinary research project by Technische Hochschule Nürnberg and Wolf GmbH, supported by Paracelsus Medical University Salzburg, comes in. It investigates the following key questions: • How can good and healthy indoor air quality in classrooms be achieved? • How can mechanical ventilation systems be operated as energy-efficiently as possible? • What practical potentials and pitfalls can arise in real-world application? The focus is on decentralized air handling units with outdoor air exchange, as these are well suited for retrofitting educational facilities. For a holistic comparison, a central ventilation system and manual window airing combined with CO2 monitors are also included in the study. The project examines the effects on both physical parameters and human well-being, addressing indoor air quality, thermal comfort, health, and energy use. To comprehensively assess ventilation strategies, the project combines simulation studies with empirical field research. Over a seven-month controlled observational study during the 2023/24 winter infection season, three ventilation concepts were investigated in practice at three primary schools: • Manual window airing in combination with CO2 monitors • Mechanical ventilation via decentralized air handling units • Mechanical ventilation via a central ventilation system Data on indoor air quality, thermal climate and window opening states in eight classrooms and weather conditions at the three school locations were recorded in an extensive long-term monitoring. Questionnaires were conducted on students’ perceived comfort and well-being, as well as cold symptoms. In addition, saliva samples were analyzed for infection markers. Computational fluid dynamics (CFD) simulations were used to examine ventilation concepts for decentralized air handling units, and annual building performance simulations of six ventilation strategies were carried out using coupled thermal-energy models. Based on findings from both simulation and field study, practical recommendations for effective and efficient school ventilation concepts were developed, and potential pitfalls in the use of mechanical systems were identified. Properly planned and well-operated ventilation systems – ideally featuring heat recovery and demand-based control – can help ensure high indoor air quality in classrooms, reduce infection risks, maintain thermal comfort and save energy. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:92-opus4-43030 SP - 2 EP - 179 PB - Ohm CY - Nürnberg ER -