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- Performance assessment of a building integrated photovoltaic thermal system in Mediterranean climate : a numerical simulation approachPublication . Bot, Karol; Aelenei, Laura Elena; Gomes, Maria da Glória; Silva, CarlosABSTRACT: This study addresses the thermal and energy performance assessment of a Building Integrated Photovoltaic Thermal (BIPVT) system installed on the facade of a test room in Solar XXI, a Net Zero Energy Building (NZEB) located in Lisbon, Portugal. A numerical analysis using the dynamic simulation tool EnergyPlus was carried out for assessing the performance of the test room with the BIPVT integrated on its facade through a parametric analysis of 14 scenarios in two conditions: a) receiving direct solar gains on the glazing surface and b) avoiding direct solar gains on the glazing surface. Additionally, a computational fluid dynamics (CFD) analysis of the BIPVT system was performed using ANSYS Fluent. The findings of this work demonstrate that the BIPVT has a good potential to improve the sustainability of the building by reducing the nominal energy needs to achieve thermal comfort, reducing up to 48% the total energy needs for heating and cooling compared to the base case. The operation mode must be adjusted to the other strategies already implemented in the room (e.g., the presence of windows and blinds to control direct solar gains), and the automatic operation mode has proven to have a better performance in the scope of this work.
- Performance assessment of a building-integrated photovoltaic thermal system in a Mediterranean climate: an experimental analysis approachPublication . Bot, Karol; Aelenei, Laura Elena; Goncalves, Helder; Gomes, Maria da Glória; Silva, Carlos SantosABSTRACT: The experimental investigation of building-integrated photovoltaic thermal (BIPVT) solar systems is essential to characterise the operation of these elements under real conditions of use according to the climate and building type they pertain. BIPVT systems can increase and ensure energy performance and readiness without jeopardising the occupant comfort if correctly operated. The present work presents a case study's experimental analysis composed of a BIPVT system for heat recovery located in a controlled test room. This work contribution focuses on the presentation of the obtained measured value results that correspond to the BIPVT main boundary conditions (weather and room characteristics) and the thermal behaviour and performance of the BIPVT system, located in the Solar XXI Building, a nZEB exposed to the mild Mediterranean climate conditions of Portugal.
- Passive adaptive façades : examples from COST TU1403 working group 1Publication . Mazzucchelli, Enrico Sergio; Aelenei, Laura Elena; Gomes, Maria da Glória; Karlessi, Theoni; Alston, Mark; Aelenei, DanielABSTRACT: Buildings often adopt strategies based on the integration of solutions and technologies in façades capable of changing their behaviour in time to improve energy efficiency and comfort. Considering that the envelope is the main parameter that influences the energy performance of buildings, façade elements with adaptive features can provide the buildings the necessary flexibility needed in terms of energy flow and thermal comfort in the context of nZEB, where the buildings must be interactive in the zero energy and smart city context. Several different types of adaptive façade concepts have already been developed, and an increase in emerging, innovative solutions is expected in the near future. However, when referring to adaptive technologies, two main categories can be distinguished. Adaptive technologies, which rely on passive design to improve building energy efficiency and comfort, and active technologies which include renewable harvesting. The aim of this paper is to provide several examples of passive adaptive technologies and their performance features from COST TU1403 Working Group 1 database.
- Assessing energy, thermal and visual performance of photochromic glazing: From spectrophotometric characterization to building simulationsPublication . Teixeira, Henriqueta; Moret Rodrigues, António; Aelenei, Daniel; Gomes, Maria da GlóriaABSTRACT: Photochromic (PC) glazing is a promising smart glazing solution for enhancing buildings energy efficiency and indoor comfort through its ability to dynamically adjust its optical properties in response to solar radiation. However, studies assessing the global (energy, thermal and visual) performance of this technology are scarce. This work evaluates the performance of a clear double glazing incorporating a PC film. Spectrophotometric tests were first conducted to determine the thermal and optical properties of the PC film, revealing a dynamic visible transmittance and a low UV and near-infrared transmittance. Subsequently, a previously calibrated dynamic simulation model of an office room was used to assess the impact of the PC film on energy consumption (climatization energy needs and energy use considering an ideal air-conditioning system) and indoor comfort (in accordance with useful daylight illuminance, daylight glare index, predicted mean vote, adaptive thermal comfort model and Portuguese legislation) during working hours (9am-6 pm of weekdays) across the climates of three European cities (Lisbon, Berlin and London). The results show that PC glazing can reduce cooling demand in all studied climates. Total energy use decreased by up to 10% in the warmest of the studied climates, while slight increases were observed in the colder climates. Visual comfort improved significantly, with up to 24% and 74% more working hours with useful illuminance and imperceptible glare levels, respectively. Thermal comfort analysis revealed a negligible change in free-float conditions during working hours, and an improvement of up to 20% when the HVAC system was operating.