Publications

Building performance analysis changed the way in which buildings are designed and operated. The evaluation of different design and operation options is becoming more resource intensive than ever before. Although building dynamic simulation tools are potentially a suitable way for assessing energy performance of buildings accurately, they require adequate training and a careful evaluation of model input data. In Europe, the majority of buildings were constructed before 1990 and are in urgent need for a significant energy efficiency improvement, through deep renovation. In this respect, advanced renovation solutions are available, but costly and lengthy processes and technical complexities hinder the achievement of a large scale impact. Energy refurbishment of buildings is an open challenge and essentially requires the adoption of a valid methodological approach to link design and operational performance analysis transparently, in order to address the potential gap between simulated and measured results. The HEART project, funded in the EU Horizon 2020 program, aims to address the increasing need for deep retrofit interventions and to develop systemic strategies leading to high performance and cost effective solutions. The research for the cloud platform used in the project is based on two fundamental tools: parametric simulation to produce a large spectrum of possible building energy performance outcomes (considering realistically the impact of the user behaviour and variable operating conditions from the very beginning), and model calibration employing simple, robust and scalable techniques. In this paper we present the preliminary development and testing of the computational processes that will be implemented in the cloud platform, employing the first pilot case study of HEART Project in Italy, currently under refurbishment. 

Interoperability issues on networks of heterogeneous devices create a relevant and complex challenge. The Word Wide Web Consortium (W3C) develops a series of specifications, called the Web of Things (WoT), to address this challenge. WoT is focused on integrating smart things into the application layer of a system using on Web technologies. Thus, WoT is expected to have a great impact on the smart retrofit of buildings once data from existing and future planned systems are able to be gathered and analysed seamlessly. In this paper, we (i) analyse the application of the W3C WoT on the core of the Building Energy Management System (BEMS) to enable the universal integration of both private and public systems; (ii) propose a novel architecture for the BEMS based on the W3C specifications; and (iii) present a real-world application based on this architecture. The application covered in this paper allows data gathering from sensors with standard commands, enabling data analysis with a simple collecting process. By applying these specifications, smart building retrofit can be benefited from: (i) the ability to merge and scale different systems and devices; (ii) the easiness to access data; (iii) the reduction of development and maintenance costs; and (iv) offering standard interfaces to the BEMS.

When considering the deployment of renewable energy sources in systems, the challenge of their utilization comes from their time instability when a mismatch between production and sources, such mismatch can be evened out. The use of phase-change materials (PCMs) as thermal storage has a theoretical advantage over the sensible one because of their high latent heat that is released or accumulated during the phase-change process. Therefore, the present paper is a review of latent thermal storages in hydronic systems for heating, cooling and domestic hot water in buildings. The work aims to offer an overview on applications of latent thermal storages coupled with heat pumps and solar collectors. The review shows that phase-change materials improve the release of heat from thermal storage and can supply heat or cold at a desired temperature level for longer time periods. The PCM review ends with the results from one of the Horizon2020 research projects, where indirect electrical storage in the form of thermal storage is considered. The review is a technological outline of the current state-of-the-art technology that could serve as a knowledge base for the practical implementation of latent thermal storages. The paper ends with an overview of energy storage maturity and the objectives from different roadmaps of European bodies.

In the building sector, 40% of final energy is used for heating and cooling. Up to 75% of this is used in residential buildings. It is necessary to take a step forward and reduce this share of energy consumption, in particular through the use of efficient technologies and their integration into the system of renovation of residential buildings, which is a major challenge for future research in this field. An important technology for achieving this goal is heat storage, where the use of phase change materials as heat storage material allows for a higher energy density. The main advantage of using heat storage technologies is the solution of the problem of the temporal divergence of energy demand and the possibility to use a higher share of energy from renewable sources, e.g. such as solar energy. Solar energy as a resource can be used during the day, when production is higher than demand, which allows storing energy for a later period of demand. This also improves the efficiency of the heat generators in the system in which the thermal storage is integrated. The focus of the present study is on the investigation of phase change materials (PCM) as thermal storage in the conventional water tank storage. A comparison was made between a conventional sensible thermal energy storage tank and a hybrid latent heat storage tank, where the PCM was encapsulated in cylindrical nodules and integrated into the water tank to improve the energy density of the conventional water heat storage tank. The results of the experiment showed that 15% of the PCM inside the water storage tank increases heat storage for 70% over conventional heat storage tank with water only inside. The measured experimental data were compared with the simulation results from TRNSYS model to enable further analysis and improvement of the heat storage tank with PCM integration.

Prudent and efficient utilization of renewable energy sources is needed in order to achieve clean energy transition. Since energy use in buildings represents around 40% of total energy use in European Union the reduction of energy use in this sector is most definitely needed. One of the great challenges in this sector represents retrofit of residential buildings where 3/4 of buildings in Europe are residential. To reduce energy consumption and increase the use of renewables in existing residential buildings to achieve nearly zero energy buildings (nZEB) a holistic approach of retrofit with interconnected technological system is needed. In the first part of this paper the nZEB and thermal energy storage are introduced for further implementation of the phase change material (PCM) into storage tank. Furthermore, energy toolkit based on the synergetic interaction between technologies integrated in the system for holistic retrofit of residential buildings, which is under development within HEART project (HORIZON 2020), is presented. In this project step towards self-sufficient heating and cooling of building is made with increase in on-site consumption of self-produced energy from solar energy and interconnection between PV, electrical storage, heat pump, thermal energy storage, fan coil heat pump, cloud based decision support and building energy management system. With such a smart energy system the almost zero-energy buildings will be possible to decrease energy use in residential sector. Improvement of sensible thermal energy storage with implemented cylindrical modules filled with PCM is investigated experimentally. The results from experiment show that thermal energy storage unit with integrated modules filled with PCM can supply desired level of water temperature for longer period of time. The advantage of PCM in thermal energy storage is in applications that needs narrow temperature range of supplying and storing thermal energy what is the subject matter of consideration in the case of HEART project.

Prudent and efficient utilization of renewable energy sources is needed in order to achieve clean energy transition. Since energy use in buildings represents around 40% of total energy use in European Union the reduction of energy use in this sector is most definitely needed. One of the great challenges in this sector represents retrofit of residential buildings where 3/4 of buildings in Europe are residential. To reduce energy consumption and increase the use of renewables in existing residential buildings to achieve nearly zero energy buildings (nZEB) a holistic approach of retrofit with interconnected technological system is needed. In the first part of this paper the nZEB and thermal energy storage are introduced for further implementation of the phase change material (PCM) into storage tank. Furthermore, energy toolkit based on the synergetic interaction between technologies integrated in the system for holistic retrofit of residential buildings, which is under development within HEART project (HORIZON 2020), is presented. In this project step towards self-sufficient heating and cooling of building is made with increase in on-site consumption of self-produced energy from solar energy and interconnection between PV, electrical storage, heat pump, thermal energy storage, fan coil heat pump, cloud based decision support and building energy management system. With such a smart energy system the almost zero-energy buildings will be possible to decrease energy use in residential sector. Improvement of sensible thermal energy storage with implemented cylindrical modules filled with PCM is investigated experimentally. The results from experiment show that thermal energy storage unit with integrated modules filled with PCM can supply desired level of water temperature for longer period of time. The advantage of PCM in thermal energy storage is in applications that needs narrow temperature range of supplying and storing thermal energy what is the subject matter of consideration in the case of HEART project.

The huge amount of energy consumed by the residential buildings makes the sector one of the principal sources affecting the energy use in the European countries. To face it, the renovation of the building stock is considered one of the key strategies to improve the energy performance of buildings and meet the energy efficiency targets. Thus, a full understanding of the building stock and renovation market is crucial to meet the objectives of energy efficiency strategies. This research presents the findings of an extensive research on the residential building stock and retrofit market in France, Italy, Spain, Slovenia and Austria and a detailed comparative analysis is developed to assess the quality and the level of the data sources. The weighting method is adopted in this paper as an analytic approach in order to evaluate the main indicators of the data collected and to highlight the commonalities and the differences of building data among European countries. The results of this analysis are considered as valuable vademecum aims to support the experts and the different stakeholders in the data collection process and initiates the opportunities for standardizing data collected from European countries.

The building sector in the world is responsible for nearly 36% of the final energy consumption and nearly 40% of total direct and indirect CO2 emissions. Reducing buildings energy consumption is an absolute necessity, and one of the most efficient methods is the estimation and optimization of building energy performance. One of the significant factors affecting the building energy performance is the occupant behaviour. Recently, there has been growing interest in the occupant behaviour field. Within the framework of this context, different methods have been proposed and developed especially when the traditional methods, such as interview and survey, are not efficient and sufficient to analyse and to predict the occupant behaviour with better accuracy. This research provides a comprehensive characterization of the occupant behaviour through, a review of current approaches for occupant behaviour analysis. The main key issues and drivers affecting the energy behaviour of habitants identified on the literature were synthetised and presented. Furthermore, the paper highlights the necessity of including the energy feedback programs as a main key in the topic of occupants, in order to integrate them in the building process.