• Energy Research
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The building envelope has high potential to reduce the energy consumption of buildings according to the International Energy Agency (IEA) because it is involved along all the building process: design, construction, use, and end-of-life. The present study compares the thermal behavior of seven different building prototypes tested under Mediterranean climate: two of them were built with sustainable earth-based construction systems and the other five, with conventional brick construction systems. The tested earth-based construction systems consist of rammed earth walls and wooden green roofs, which have been adapted to contemporary requirements by reducing their thickness. In order to balance the thermal response, wooden insulation panels were placed in one of the earth prototypes. All building prototypes have the same inner dimensions and orientation, and they are fully monitored to register inner temperature and humidity, surface walls temperatures and temperatures inside walls. Furthermore, all building prototypes are equipped with a heat pump and an electricity meter to measure the electrical energy consumed to maintain a certain level of comfort. The experimentation was performed along a whole year by carrying out several experiments in free floating and controlled temperature conditions. This study aims at demonstrating that sustainable construction systems can behave similarly or even better than conventional ones under summer and winter conditions. Results show that thermal behavior is strongly penalized when rammed earth wall thickness is reduced. However, the addition of 6 cm of wooden insulation panels in the outer surface of the building prototype successfully improves the thermal response. This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE), from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES) and the Spanish government (ULLE10-4E-1305, ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA-UdL (2014 SGR 123) and the city hall of Puigverd de Lleida. GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. Álvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014- 19940.

This paper describes a building prototype experimental set-up used for testing active and passive systems for energy savings, presenting the used methodology, reviewing the main experimental results and identifying limitations. The test facility is located in Puigverd de Lleida (Spain) and has been experimentally evaluating different materials, technologies and systems which might be integrated in building design to provide energy savings for space heating and cooling since 2002. The research fields of passive technologies covered the effect of using different insulating materials, construction systems based on sustainable materials, addition of phase change materials in building envelopes and green infrastructures such as green roofs and walls. On the other hand, the active systems tested were focused in exploiting different available renewable energy source available, such a solar thermal, free-cooling with night air, or geothermal heat, using thermal energy storage systems to shift the heating and cooling loads. The work partially funded by the Spanish Government (ENE2008-06687-C02-01/CON, ENE2011-28269-C03-02, ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER), and ULLE10-4E-1305). Financiado por el proyectoRTC-2015-3583-5 (INPHASE) del Ministerio de Economía y Competitividad, dentro del Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad, en el marco del Plan Estatal de Investigación Científica y Técnica y de Innovación 2013–2016, y ha sido cofinanciado con FONDOS FEDER, con el objetivo de promover el desarrollo tecnológico, la innovación y una investigación de calidad GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and the city hall of Puigverd de Lleida. The research leading to these results has received funding from the European Union's Seventh Framework Programe (FP7/2007-2013) under grant agreement no. PIRSES-GA-2013-610692 (INNOSTORAGE), from MOPCON Project (EU CRAFT ref. G5ST-CT-2002-50331), from Eccoinnovation Project Rewastee ECO/13/630286 and from European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 657466 (INPATH-TES) and from EEA-Grants under grant IDI-20140914. This work was supported by the “Corporación Tecnológica de Andalucía” by means of the project “MECLIDE-Soluciones estructurales con materiales especiales para la climatización diferida de edificios” with the collaboration of DETEA. Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Julià Coma would like to thank the Departament d′Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship. Cecilia Castellón, Pablo Arce, Albert Castell, Cristian Solé, Pere Moreno and Lídia Rincón participated in the experimentation in this set-up.

Extensive green roofs have been consolidated as good tools for passive energy saving systems in buildings,providing a more sustainable trend in the building field. However, as the growth of vegetation is variable depending on external factors such as weather conditions, disease, etc. the coverage of plants cannot ensure uniformity and consequently the 'shadow effect' cannot be considered as a constant parameter.On the other hand, materials used in substrate and drainage layers should provide a constant 'insulation effect' depending only on their physical properties and water content. In spite of this, the complexity of disaggregated materials used in internal layers of extensive green roofs implies a lack of real data about their thermal properties. The main objective of this study is to determine experimentally the physical properties of different disaggregated materials from the internal layers of extensive green roofs commonly used in Mediterranean climates. The experimentation presented in this paper allows to calculate the thermal transmittance in steady-state (U-value), the heat storage capacity (Cp), and the dynamic thermal response under a daily thermal oscillation. This work was partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ULLE10-4E-1305), in collaboration with the company Buresinnova S.A (C/Roc Boronat 117-125, baixos 08018 Barcelona). Moreover, the research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° PIRSES-GA-2013-610692 (INNOSTORAGE) and from European Union’s Horizon 2020 research and innovation programme under grant agreement N° 657466 (INPATH-TES). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Finally, Julià Coma wants to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de;1; Catalunya for his research fellowship.

A building prototype was built in the experimental set-up located in Puigverd de Lleida (Spain) to study the energy performance of a radiant wall with ventilated facade cooled with a ground coupled heat-exchanger. The installed geothermal heat pump operates only as a ground coupled heat exchanger on cooling mode, thus providing free-cooling. In this case, only the circulation pumps consume power. The summer experimental campaign showed the energy savings potential and the peak load shifting ability of the system. On continuous operation and taking as reference a cubicle equipped with a conventional air-to-air heat pump, the radiant wall cooled with the ground coupled heat-exchanger achieved savings up to 54.17% and 82.08% at set-point temperatures of 24 °C and 26 °C, respectively. The thermal storage capacity of the system was studied in night charging test, when the cubicles were pre-cooled during night-time. During the day, the temperature raise caused by heat loads was small and the system kept the temperature inside comfort range despite it only operated overnight. However, the performance was very sensitive to set-point temperature. Free-cooling was limited by the temperatures in the boreholes, showing that with lower set-points the gradient between supply temperature and room temperature was small, and thus it required a higher water flow to achieve the necessary cooling power. Intermittent operation of the system according to different schedules also affected the radiant walls performance as they interacted with the thermal inertia of the system, which could even have a negative impact on energy use. The work partially funded by the Spanish government (ULLE10-4E-1305, ENE2015-64117-C5-1-R(MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and the city hall of Puigverd de Lleida. This projects has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement No. PIRSES-GA-2013-610692 (INNOSTORAGE) and from European Union’s Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES) and from EEA-Grants under grant IDI-20140914. Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

A radiant wall heating system embedded in a heavy brickwork envelope and coupled to a ground source heat pump supplied has been experimentally tested under real outdoor conditions. This system was applied to a room sized cubicle built in Puigverd de Lleida (Spain) test-site, where it was studied in system vs. system analysis in comparison to a reference cubicle built with commercial available technologies (insulated alveolar brick wall and air-to-air heat pump). The results showed the potential of the radiant wall, which in continuous operation reached energy savings between 19.97% and 40.72% based on set-point temperature. Most important, the active thermal mass of radiant wall allowed operating in off peak periods. Otherwise, this peak load shifting ability was completely inexistent in the reference cubicle. However, the results show that the radiant cubicle was unsuited to operate in occupancy schedules due to its slow response time. Furthermore, the tests show that optimization of the radiant wall system requires a control strategy that takes in account the dynamics of the system. The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER), TIN2015-71799-C2-2-P and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and the city hall of Puigverd de Lleida. This projects has received funding from the European Commission Seventh Framework Programme (FP/2007–2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE) and from European Union's Horizon 2020 research and innovation programme under grant agreement Nº 657466 (INPATH-TES) and from EEA-Grants under grant IDI-20140914. Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

During the last decade, vertical greenery systems are increasing their presence in building designs, providing several urban ecosystem services. One of them is the potential to provide energy savings in buildings, which develops an important role, however, data about its performance during winter periods is still scarce. Therefore, the main objective of this paper is to compare at real scale the thermal performance of two different vertical greenery systems implemented in experimental houses-like cubicles for both cooling and heating periods. A double-skin green facade has been installed in the first cubicle that uses deciduous creeper plants, while the second one is designed with green walls made with evergreen species. Finally, a third identical cubicle without any green coverage is used as reference. Two different types of experiments have been carried out to test the performance of the house like-cubicles. One consists of controlling the internal ambient temperature providing heating or cooling to maintain the desired comfort conditions. On the other hand, to study the thermal response of the construction system, the heating, ventilation and air conditioning system was disconnected and the cubicles were tested under free floating condition. First results showed a high potential for energy savings during cooling season for green wall (58.9%) and double-skin green facade (33.8%) in comparison to the reference system. On the other hand, for heating periods no extra energy consumption was observed for evergreen system. The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER) and ULLE10-4E-1305) in collaboration with the company Buresinnova S.A (C/Saragossa, 95 Entsol 3a, 08006 BARCELONA). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and to the city hall of Puigverd de Lleida. This study has received funding from the European Commission Seventh Framework Programme (FP/2007–2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE) and from European Union's Horizon 2020 research and innovation programme under grant agreement Nº 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Julià Coma would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship.

Abstract Sustainability of building construction systems depends on their material and energy consumption, and the consequent environmental impact. Thus, the evaluation of their sustainability requires a wide analysis that includes these three topics. Material Flow Analysis (MFA) and Life Cycle Assessment (LCA) used together can offer a full environmental evaluation. For this reason, in this study, five different facade constructive systems are evaluated with MFA and LCA to compare them from an environmental point of view. The constructive systems were monitored in an experimental set-up located in Mediterranean continental climate, registering energy consumptions for summer and winter periods. MFA evaluated their total material requirement and the ecological rucksack. LCA evaluated their impact on the environment. The energy parameter considered the embodied energy of the materials and the energy consumption registered in the experimental set-up. MFA results show the significant quantity of natural resource extraction required for building which leads to a considerable ecological rucksack. On the other hand, LCA results show the importance of the operational phase of the building in the overall building energy consumption, and therefore in the environmental impact.