Roberto Garay

Roberto Garay
Tecnalia · Building Technologies

Doctor of Philosophy

About

87
Publications
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347
Citations

Publications

Publications (87)
Article
Full-text available
District heating networks are considered to be a key element for the decarbonization of Europe. The RELaTED project seeks to contribute to the decarbonization of these infrastructures with the demonstration of low temperature district heating networks. One of the demonstration sites consists of more than 50 substations within a subsection of a larg...
Article
Full-text available
An accurate characterization and prediction of heat loads in buildings connected to a District Heating (DH) network is crucial for the effective operation of these systems. The high variability of the heat production process of DH networks with low supply temperatures and derived from the incorporation of different heat sources increases the need f...
Article
Full-text available
The present paper focuses on the architectural and constructional features required to ensure that building envelope renovation are safe, functional, and adaptable to the building stock, with particular focus on “plug and play” modular facade construction systems. It presents the design of one such system and how it addresses these issues. The outc...
Article
Full-text available
District heating networks deliver around 13% of the heating energy in the EU, being considered as a key element of the progressive decarbonization of Europe. The H2020 REnewable Low TEmperature District project (RELaTED) seeks to contribute to the energy decarbonization of these infrastructures through the development and demonstration of the follo...
Article
Full-text available
A large share of the city of Belgrade is heated by a District Heating network. Established in 1965, the network delivers 3.6 TWh to more than 20 million square meters of households industries and businesses, by means of a 1460km-long network. The system has been continuously upgraded and adapted to new technologies and already operates at relativel...
Article
Full-text available
The use of smart energy meters enables the monitoring of large quantity of data related to heat consumption patterns in buildings connected to DH networks. This information can be used to understand the interaction between building and the final users´ without accurate information about building characteristics and occupational rates. In this paper...
Article
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(1) The overall energy requirement of a building may be impacted by the building design, the selection of materials, the construction methods, and lifecycle management. To achieve an optimum energy-efficiency level when dealing with a new building or renovation project, it is important to improve the entire construction process as it is not enough...
Article
Full-text available
This paper conducts an energy and economic assessment of District Heating (DH) integrated Solar Thermal (ST) systems. An implementation with building-integrated ST collectors coupled to a Low Temperature District Heating (LTDH) system is studied, with special focus on unglazed collectors. ST heat is exploited in the building through direct use, whi...
Technical Report
Full-text available
Task 56 is part of the Solar Heating and Cooling Programme (SHC) of the International Energy Agency (IEA). Within Task 56, Subtask B aims to develop tools and strategies to foster the market penetration for industrialised solar envelope systems. This report outlines strategies for stakeholders of solar building envelopes (SBE) in order to deal with...
Article
Building envelope systems are rapidly evolving, driven by increasingly stringent requirements for limiting energy consumption. Current trends favour lightweight, prefabricated wall assemblies with high levels of insulation, which have been shown to be particularly sensitive to thermal bridging through anchoring and framing elements. This paper pres...
Article
Full-text available
Ventilated façade systems, incorporating thermal insulation behind a rear-ventilated cladding, constitute a popular renovation solution in warm European climates. For compliance with building regulations, their energy efficiency is usually obtained through simple onedimensional desktop calculations, which do not consider the impact of the support e...
Article
Full-text available
Heating load in Commercial buildings is highly related with ventilation systems, while at the same time local discomfort in the vicinity of glass walls occurs due to overheating. In this paper, a novel double envelope curtain wall is presented, which extracts heat from the façade by means of a ventilated cavity which is then incorporated to the ven...
Article
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A bio-based multi-layer building envelope assembly has been developed for its integration in newly built and retrofitted buildings. Forest-based materials and biocomposite profiles are used as an alternative to fossil-based insulants and metallic framing, providing a well-insulated and low-thermal-bridge technical solution. The wall assembly has be...
Article
Full-text available
In the last decades, a growing industry has been created in relation to building envelope retrofits. Linked to the lack of financial capacity of many building owners, innovative instruments such as energy performance contracts have been promoted by public bodies. This kind of instruments require of detailed energy assessment processes in order to d...
Article
Full-text available
The design and modelling of a calorimetric test infrastructure for building envelopes is performed for the side-by-side assessment of different building envelope systems. The infrastructure is designed for representing transient weather conditions in Middle east. It consists of 3 “cold” experimental chambers and a larger “hot” experimental chamber....
Technical Report
Full-text available
The present document includes a state-of-the-art review of solar envelope systems that are already on the market or that can potentially reach that stage in a short-medium timeframe (Technology Readiness Level ≥ 4). The analysis focuses on the technological integration of such solutions in the envelope and building, but non-technical issues such as...
Article
Full-text available
District-Heating (DH) covers around the 9% of the total heat demand in the EU, with a proven highperformance levels and low operational costs. DH may suffer adaptations in order to maintain competitiveness with individual heating systems. The most important one is the reduction of supply temperatures up to 50°C, emerging the concept of Ultra Low Te...
Article
Full-text available
District Heating (DH) are a very efficient system for heating in urban areas and they are considered as key elements for the de-carbonization of the European Cities. High performance levels and low operational energy costs are part of the identity of these heating networks. The reduction of supply-line temperatures allows the possibility to introdu...
Conference Paper
Full-text available
This paper presents a theoretical simulation of thermal and economical assessment of façade integrated Solar Thermal (ST) in combination with Ultra Low Temperature (ULT) District-Heating (DH). This paper is in line with existing R&D activities for the integration of unglazed systems in building envelopes, where facades provide an almost unexplored...
Conference Paper
Full-text available
District Heating (DH) are a very efficient system for heating in urban areas and they are considered as key elements for the de-carbonization of the European Cities. High performance levels and low operational energy costs are part of the identity of these heating networks. The reduction of supply-line temperatures allows the possibility to introdu...
Conference Paper
Full-text available
District-Heating (DH) covers around the 9% of the total heat demand in the EU, with a proven high-performance levels and low operational costs. DH may suffer adaptations in order to maintain competitiveness with individual heating systems. The most important one is the reduction of supply temperatures up to 50ºC, emerging the concept of Ultra Low T...
Conference Paper
Full-text available
This paper explores the techno-economic viability of coupling unglazed solar thermal façade system with a low temperature district heating network. this concept allows a more efficient control strategy for heat is allowed, where direct solar heat and heat from district heating are alternated in order to maximize the efficiency of the whole system....
Conference Paper
Full-text available
Trends for heating energy in European Cities are the decarbonization of energy sources and the reduction of heat loads. District heating (DH) networks are key systems to reach the targets due to the cost competitiveness and high performance levels they show. However, DH networks require a conversion to adapt for the need of the future. It is necess...
Presentation
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Article
Full-text available
A new method is proposed for the assessment of heat transfer in building envelopes. This method is built side-by-side with existing standardized numerical and experimental procedures to extend their present scope to transient, multi-dimensional heat transfer assessment under on-site experimental conditions. An overall framework is designed and vali...
Presentation
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Conference Paper
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Talk Abstract District Heating systems are considered to be one of the most effective heat supply systems in urban areas. District Heating systems are commonly supplied by a set of different heat production plants. In mature systems, heat production technologies have evolved over time. To-date, District heating systems are mostly supplied from larg...
Technical Report
Full-text available
This report is a result of extensive discussions within Task 56 of the Solar Heating and Cooling Programme (SHC) of the International Energy Agency (IEA). Innovative solar envelope technologies face multiple barriers, which prevent some of these innovations from contributing significantly against climate change. This report presents the barriers th...
Conference Paper
Full-text available
Today's measured rate of refurbishment is much lower than the one which should be observed to remain in line with Europe 2050 ambitions: there is a need to accelerate the market uptake and large-scale implementation of energy efficient refurbishment solutions thanks to innovative strategies. One of the most important components to be addressed with...
Article
Full-text available
A methodological approach to the multi-dimensional heat transfer assessment of building envelopes is performed. The proposed method focuses on thermally weak points in envelope-structure junctions and the assessment of envelope retrofit alternatives. Thermal performance in these spots is seldom assessed in energy audit processes, although it is one...
Conference Paper
Full-text available
In most cases, building service designers choose between Solar thermal (ST) and District Heating (DH) technologies for their integration in buildings. By doing so, only a fraction of the buildings within a particular district is used for ST, while at the same time energy intensity in DH networks can be reduced. In some cases, building-integrated so...
Article
Full-text available
In this paper, the energy performance of a solar thermal (ST) façade system is studied in relation to its connection to a district heating system. This concept allows for the direct use of ST heat in the building, while taking profit from the network for delivery/selling of excess heat and purchase of heat during periods of underproduction. The use...
Conference Paper
Full-text available
There is a growing demand for curtain walls within the European Union, coming mainly from the commercial sector and especially targeted to office buildings. Despite recent efforts on heat loss mitigation (relying on additional glass panes, coatings or thermal breaks to framing elements) curtain walls remain a significant contributor to the energy c...
Conference Paper
Full-text available
This paper presents an innovative and standardized system for roofs and façades, integrating different technological solutions that improve the energetic efficiency, thermal, acoustic and light comfort, as well as air quality in buildings. The BRESAER system combines industrialized active and passive solutions and nanotechnology over one common mod...
Preprint
Full-text available
This paper presents an innovative and standardized system for roofs and façades, integrating different technological solutions that improve the energetic efficiency, thermal, acoustic and light comfort, as well as air quality in buildings. The BRESAER system combines industrialized active and passive solutions and nanotechnology over one common mod...
Conference Paper
Full-text available
In this article it is presented an innovative façade system with a solar thermal system. The developed solar system can be classified as modular unglazed collector, designed for low temperature energy capture. It is compatible with a solar combined system that integrates a solar heat pump. The external appearance of the building remains untouched t...
Conference Paper
Full-text available
Dados los retos medioambientales marcados por la UE para el año 2020 y el fomento por parte de las administraciones de la implementación de tecnologías que reduzcan el consumo energético de los edificios, en los últimos años se han desarrollado numerosas soluciones de rehabilitación energética para envolventes. Actualmente, las soluciones convencio...
Conference Paper
Full-text available
Rear-ventilated rainscreen façade insulation systems are becoming a popular retrofit solution in Southern European climates, due to their good thermal performance in both winter and summer conditions. In these assemblies, the substructure of the new cladding is anchored to the original building, thus puncturing the thermal insulation. This study as...
Conference Paper
Full-text available
District heating (DH) systems are key systems for the de-carbonization of heating energy in European Cities. In order to allow for this transition, while guaranteeing competitive energy costs, conversion of DHs is required. DH operation temperature needs to be reduced in order to increase the performance of renewable systems and operation criteria...
Article
Full-text available
In this paper, an assessment is made on a pre-fabricated timber framed hemp-based building envelope system. The hemp-lime mixture within the envelope is produced by mixing the hemp shiv with a lime formulated solution, which acts as a binder, and provides thermal insulating and moisture buffering capacity to the resulting construction.
Article
Full-text available
Thermal insulation in buildings is getting more and more performing with modern energy efficiency regulations in developed countries. Not only insulation requirements are imposed to new-built buildings, but also to refurbishment activities of the existing building stock, where availability of space is often limited. These requirements lead to incre...
Article
Full-text available
A prefabricated timber façade system is presented for the energy retrofitting of buildings. Large panel dimensions facilitate the installation of this system, with reduced disturbance to building users and increased overall quality in terms of thermal bridge mitigation and air tightness of architectural junctions. A full scale proof of concept test...
Article
Full-text available
In the current context of moving towards more sustainable construction, advanced façade systems that integrate solar collecting devices represent a commitment with future trends that combine renewable technologies with building skins. This paper describes a real experience when combining a novel unglazed solar collector based on sandwich panel tech...
Article
Full-text available
Energy signature methods are applied over three tertiary buildings in the UK, Sweden and Spain, based on both simulations and experimental data, for pre- and post-retrofit scenarios. Variations in their energy profiles relate to differences in climate severity, usage pattern (continuous/discontinuous) and HVAC scheduling. This study discusses the i...
Article
Present trends on solar thermal systems for building integration define the need of integrated solar technologies for façades. Although other possibilities exist for solar thermal systems in new buildings, solutions for a suitable integration of solar thermal systems into building retrofitting actuations are needed.
Article
Full-text available
Present trends on solar thermal systems for building integration define the need of integrated solar technologies for façades. The integration of solar systems in façades allows for the direct connection of solar systems to heated spaces, and automated air solar collectors based on the trombe-mitchell provide a suitable technology for its adoption...
Article
Heat transfer across envelopes (façade, roof, glazed areas) represents a big share of the energy flow within the heat balance of buildings. This paper focuses on areas of the envelope where multi-dimensional heat transfer occurs. These areas are commonly defined as thermal bridges, due to a localized reduction of thermal resistance of constructions...
Article
Full-text available
External Thermal Insulation Composite Systems (ETICS) are increasingly used for the energy-efficient retrofit of buildings. This paper evaluates the in-situ thermal performance of a prefabricated composite panel made of PIR and concrete, by full scale testing of a prototype installed at the KUBIK test facility. Experimental results from measurement...
Conference Paper
Full-text available
Present trends on solar thermal systems for building integration define the need of integrated solar technologies for façades. Although other possibilities exist for solar thermal systems in new buildings, solutions for a suitable integration of solar thermal systems into building retrofitting actuations are needed. This paper presents a solar ther...
Conference Paper
Full-text available
Present trends on solar thermal systems for building integration define the need of integrated solar technologies for façades. The integration of solar systems in façades allows for the direct connection of solar systems to heated spaces, and automated air solar collectors based on the trombe-mitchell provide a suitable technology for its adoption...
Conference Paper
Full-text available
Despite significant development in the performance and efficiency of solar thermal technology, little consideration has been given to its interaction within building envelopes, aside from mechanical fixing systems. The lack of solutions for the architectural integration of solar collectors and the complexity of their assembly process remain importa...
Conference Paper
Full-text available
External Thermal Insulation Composite Systems (ETICS) are increasingly used for the energy-efficient retrofit of buildings. This paper evaluates the in-situ thermal performance of a prefabricated composite panel made of PIR and concrete, by full scale testing of a prototype installed at the KUBIK test facility. Experimental results from measurement...
Conference Paper
Full-text available
In this paper, an assessment is made on a pre-fabricated timber framed hemp-based building envelope system. The hemp-lime mixture within the envelope is produced by mixing the hemp shiv with a lime formulated solution, which acts as a binder, and provides thermal insulating and moisture buffering capacity to the resulting construction. Hemp, by its...
Conference Paper
Full-text available
Thermal insulation in buildings is getting more and more performing with modern energy efficiency regulations in developed countries. Not only insulation requirements are imposed to new-built buildings, but also to refurbishment activities of the existing building stock, where availability of space is often limited. These requirements lead to incre...
Conference Paper
Full-text available
Until very recently, technical systems such as solar thermal systems, and other HVAC elements have been conceptualized based uniquely in their thermal performance levels, and its integration with other architectural elements (envelopes, slabs,…) limited to mechanical fixation. However, with steadily increasing use of technologies for the reduction...
Conference Paper
Full-text available
Resumen Esta comunicación presenta el desarrollo de una meodología para la evaluación de la mejora en las prestaciones térmicas de las envolventes edificatorias tras la realización de actuaciones de rehabilitación. Particularmente, se focaliza en el comportamiento térmico de los elementos multidimensionales tales como el encuentro entre los forjado...
Conference Paper
Full-text available
Las fachadas ventiladas son una solución cada vez más utilizada debido a sus buenas prestaciones de durabilidad y eficiencia energética. En estas envolventes, la subestructura que soporta el acabado exterior interrumpe necesariamente la continuidad del aislamiento en los puntos de anclaje sobre la hoja interior. Este estudio analiza el impacto de e...
Article
Full-text available
In the context of increasing energy costs and the need for global reduction of CO2 emissions, the development of superinsulation materials for the construction sector allows the design of low-energy buildings. Since still being in an experimental or at early-commercial stage, R&D of these materials focused on its final application is required, to a...