Davide Calì

• Doctor of Engineering
• PostDoc Position at Technical University of Denmark

Renewable Energy Sources play a key role in smart energy systems. To achieve 100% renewable energy, utilizing the flexibility potential on the demand side becomes the cost-efficient option to balance the grid. However, it is not trivial to exploit these available capacities and flexibility options profitably. The amount of available flexibility is...

Multiple studies suggested that existing thermal comfort models inadequately predict occupants' individual thermal preferences. Personalised comfort models offer an alternative to conventional comfort models aiming to forecast individual's thermal preference. Implementation of these personalised models in occupant-centric control of heating, ventil...

Model predictive controllers are becoming widespread in building thermal dynamic control and energy management systems. Decreasing building energy consumption, load shifting, cost reduction, and indoor air quality improvement are some of the topics that these controllers have been shown to be efficient. However, they rely on accurate models that ar...

Identifying the parameters of grey-box models requires enough data collected from sensors installed inside and outside of the building for long enough period of time. Consequently, this process is time consuming, costly especially in large buildings that require more sensors, and can only be conducted after the building is constructed. This paper i...

A comfortable indoor environment should be one of the main services buildings provide. However, technical building systems are typically designed and operated according to fixed set-point temperatures determined by the 'one-size-fits-all' principle assuming universal thermal comfort requirements, which has been questioned in the last fifty years. D...

This paper proposes non-linear autoregressive models with exogenous inputs to model the air temperature in each room of a Danish school building connected to the local district heating network. To obtain satisfactory models, the authors find it necessary to estimate the solar radiation effect as a function of the time of the day using a B-spline ba...

This paper introduces a non-linear grey-box (GB) model based on stochastic differential equations that describes the heat dynamics of a school building in Denmark, equipped with a water-based heating system. The building is connected to a local district heating network through a heat exchanger. The heat is delivered to the rooms mainly through radi...

Smart and flexible operation of components in district heating systems can play a crucial role in integrating larger shares of renewable energy sources in energy systems. Buildings are one of the crucial components that will enable flexibility in the district heating by using intelligent operation. Recent work suggests that such improved operation...

The focus on energy conservation in buildings is increasing. Despite that, the yearly building renovation rate is only at around 1 %. To increase the renovation rate, new and time-efficient methods used for screening of large building portfolios’ energy saving potential are needed. In this paper, a re-engineered take on the classical energy signatu...

In Europe, more and more data on building energy use will be collected in the future as a result of the energy performance of buildings directive (EPBD), issued by the European Union. Moreover, both at European level and globally it became evident that the real energy performance of new buildings and the existing building stock needs to be document...

This work presents a novel occupancy simulation model for residential buildings. The main contribution is that occupancy is simulated at room level, as opposed to more course spatial resolutions in previous studies. The model is based on a time-use survey conducted in Denmark including several thousand households. It is formulated as an inhomogeneo...

This work presents a novel occupancy simulation model for residential buildings. The main contribution is that occupancy is simulated at room level, as opposed to more course spatial resolutions in previous studies. The model is based on a time-use survey conducted in Denmark including several thousand households. It is formulated as an inhomogeneo...

This work presents a novel occupancy simulation model for residential buildings. The main contribution is that occupancy is simulated at room level, as opposed to more course spatial resolutions in previous studies. The model is based on a time-use survey conducted in Denmark including several thousand households. It is formulated as an inhomogeneo...

The operation of heating, cooling and air-conditioning (HVAC) in buildings often adheres to fixed time schedules. However, associating HVAC schedules to the occupant’s presence patterns can save a significant amount of energy, reducing operation periods to the required minimum. Therefore, automated occupancy estimation provides valuable input to ef...

In the existing building stock, heating, cooling and ventilation often run on fixed schedules assuming maximal occupancy. However, fitting the control of the HVAC system to the building's real demand offers large potential for energy savings over the status quo. Building occupants' presence as well as mechanically supplied and infiltrated airflow r...

In the existing building stock, heating, cooling and ventilation often run on fixed schedules assuming maximal occupancy. However, fitting the control of the HVAC system to the building's real demand offers large potential for energy savings over the status quo. Building occupants' presence as well as mechanically supplied and infiltrated airflow r...

In the existing building stock, heating, cooling and ventilation often run on fixed schedules assuming maximal occupancy. However, fitting the control of the HVAC system to the building's real demand offers large potential for energy savings over the status quo. Building occupants' presence as well as mechanically supplied and infiltrated airflow r...

Real energy performance of new and retrofitted buildings often consistently differs from expectations. While occupants might complain about poor indoor climate, the energy use in such buildings is often higher than expected, leading to the well-known phenomenon called "Energy Performance Gap". In the past years, monitoring of buildings, both in ter...

In the existing building stock, heating, cooling and ventilation usually run on fixed schedules, in many cases, even all day. In particular, ventilation systems often run with a constant air flow rate that is adjusted based on the assumption of maximum occupancy. Hence, reducing the operation to the required extent would offer energy potential. Mod...

In the existing building stock, heating, cooling and ventilation often run on fixed schedules assuming maximal occupancy. However, fitting the control of the HVAC system to the building’s real demand offers large potential for energy savings over the status quo. Building occupants’ presence as well as mechanically supplied and infiltrated airflow r...

Real energy performance of new and retrofitted buildings often consistently differs from expectations. While occupants might complain about poor indoor climate, the energy use in such buildings is often higher than expected, leading to the well-known phenomenon called “Energy Performance Gap”. In the past years, monitoring of buildings, both in ter...

This paper complements existing Smart City taxonomies with a case study of concrete cross-boundary collaboration between actors from diverse disciplines and institutions. The paper explores technical, social and organizational aspects of indoor climate in public buildings in Copenhagen, and outlines a digital platform (skoleklima.dk/climify.org) fo...

This paper discusses the validation and adjustment of the CO2 based occupancy detection algorithm introduced by Calì et al. (Calì, 2015), based on new data gathered at the E.ON Energy Research Center main building in Aachen in 10 multi-person offices. In addition to the new data basis, further adjustments of the algorithm to the given conditions an...

Link to the article: https://authors.elsevier.com/a/1WqvU1HudMvuwB - Abstract - New and retrofitted buildings often do not perform as expected. In fact, the real energy performance of a building depends on deterministic characteristics (e.g. building's structure and HVAC), and on stochastic elements (e.g. occupants' behavior). Probabilistic model...

Smart gadgets overflowed the market within the last years. Connected cars, automated houses, smart wearables are changing our everyday life. Smart gadgets help us solving many complex tasks in an optimal way. In homes for instance, we can let them run our heating, ventilation and air conditioning systems (HVAC). Within the Smart Cities Accelerator...

We propose an advanced modelling framework to predict the scope and effects of behavioural diversity regarding building occupant actions on window openings, shading devices and lighting. We develop a statistical approach based on generalised linear mixed models to account for the longitudinal nature of observations on occupants, and to provide a co...

Link to pdf: https://publications.rwth-aachen.de/record/677868 Buildings account for up to 40% of the primary energy consumption in Europe. Therefore, ambitious energy saving targets of the European Union (Energy Roadmap 2050) have to include building stock energy retrofit. However, many field test studies show a discrepancy between expected and m...

The real energy performance of buildings depends both upon deterministic aspects (building's physics and engineering systems) and probabilistic aspects such as weather and occupant behavior. Occupant behavior is usually not directly considered when calculating the expected energy performance of buildings. In fact, field test studies all over the wo...

Low insulation standards and obsolete heating systems of a large amount of buildings in Europe account for disproportional energy consumption. Within this project, the holistic renovation and the results from the monitoring activity of buildings from a field test, located in Southern Germany, are presented. The buildings, built at the end of the 19...

Real energy performances of buildings depend not only on deterministic aspects, such as building physics and HVAC systems, but also on stochastic aspects such as weather and occupants’ behavior. Typically, occupant behavior is not adequately considered when calculating the expected performance. As a result, field test studies all over Europe have s...

In den letzten Jahren wurden die Anforderungen der EnEV seitens des Gesetzgebers an die thermische Gebäudehülle bei Sanierungen und Neubauten strenger. Die dadurch sinkenden Transmissionswärmeverluste nach außen führen zu einer zunehmenden Bedeutung der Wärmeverschiebungen innerhalb des Gebäudes. Die Bestimmung der hier vorgestellten Wärmetransmiss...

The detection of occupants in indoors can be fundamental for a correct operation of the installed engineering systems (e.g. lighting, ventilation, heating and cooling). Further, real occupancy profiles can be used as input of stochastic models for dynamic simulation of buildings and their engineering systems. In this work an algorithm for the detec...

Auf den Gebäudebereich entfallen in Europa rund 40 % des Endenergieverbrauchs und somit etwa ein Drittel der CO2‐Emissionen. In Deutschland wurden drei Viertel der Bestandsgebäude vor 1979 erstellt, die meisten dieser Gebäude sind gar nicht oder kaum energetisch saniert. Die Sanierungsquote ist momentan sehr gering und liegt bei knapp 1,1 %. Hier s...

This work introduces a multiphysics test bed which supports the testing of renewable energy systems in the context of home energy systems (HESs). The test bed, based on power-hardware-in-the-loop (PHIL) technology, allows for testing renewable energy systems and HESs in a holistic way. Homes, as the melting pot of different forms of energy, are one...

The complete refurbishment of nine buildings, each containing ten apartments of 72 m2 is presented, and preliminary results are shown. The buildings have a different retrofit scenario in terms of insulation, heat production and delivery, domestic hot water production and air–handling systems. Following the energy saving ordinance for buildings in G...

This paper presents the concept of Dual Demand Side Management (2DSM) as an evolution of the conventional Demand Side Management concept. 2DSM accounts at the same time on one hand for the local needs, i.e. energy efficiency of the building stock as well as optimization of the local distribution grid and on the other hand for the challenges of the...

This paper describes the financial benefits of consumers while applying different operating modes to their heat pump. In order to evaluate the different operating modes a single family house with heating system has been modeled and simulated with different operation strategies of the heating system and exposed to different electricity tariff scheme...

This paper introduces and evaluates a novel heating and cooling concept employing thermo-active building systems and environmental energy, harnessed from two 11-m3 rainwater cisterns for a 285-m2 residential building in passive house standard in Germany. The building strives for a significantly reduced primary energy use with carefully coordinated...