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Renewable energy communities (REC) are key drivers in promoting energy transition to renewable energy sources (RES). To maximise local potential for RECs, matching demand and local production requires the integration of different load profiles. Residential users prevail in urban areas while planning mixed-use neighbourhoods would contribute to having complementary loads towards urban RECs. Mixed areas can optimise the use of renewable production at different hours and limit demand pressures on the network. However, detailed spatial analyses are required to cluster building functions for long-term benefits. This work investigates which mix of building functions in urban blocks can maximise energy self-consumption and self-sufficiency. Five blocks combining residential with productive and tertiary activities are chosen, from a completely residential to a heterogeneous mix. The single loads use representative buildings for the Italian context. The integration of building functions flattens the energy peak loads in the district while increasing the use of PV production. The study identifies the residential and non-residential ratios to maximise energy selfconsumption and self-sufficiency. Domestic users would mainly exploit the production from nearby non-domestic buildings, but adequate exchange mechanisms and upgrade of infrastructure still need to be implemented.

The energy retrofitting of the existing building stock is one of the current challenging strategic objectives on the way to the European target of climate neutrality by 2050. According to the Renovation Wave plan, around 35 million existing buildings need to be upgraded to the highest energy efficiency level by 2030, and innovative technological solutions are required to achieve this ambitious goal. This paper proposes a novel solar exoskeleton for the energy and architectural retrofitting of existing buildings, called En-Solex. The system, which consists of an external steel frame that wraps around buildings like a double skin, combines passive solar gain control (shading and greening) with high-efficiency active solar systems (PV panels) optimised for integration into existing building facades. The energy-saving potential of the system with different façade configurations is evaluated on a multi-family residential building located in a Mediterranean climate. The dynamic energy simulations show that the proposed solution can reduce the energy demand for space heating and cooling by 33.4% and 25.5% respectively. The En-Solex system integration combined with generator replacement results in a maximum heating and cooling reduction equal to 80.7% and 59.6% respectively. The surplus of electricity generated, thanks to the integration of RES, can lead to a net plus target, with the building exceeding its average annual electricity demand.

Windows are considered the weakest components in the building envelope, driven by their low thermal resistance and static transmittance to solar gains. Consequently, innovative coatings are often proposed to promote energy saving performance of windows. This article investigates several flexible photochromic window films capable of reversibly modulating solar gains based on the abundance of ultraviolet radiation. The peel-and-stick films are applied to the internal glazing surface, making them suitable for window retrofits without interrupting building occupancy. The optical properties of the photochromic films are experimentally characterized at various solar radiation intensities. The results are then used to numerically evaluate the energy-saving potential of the different films for a representative room in a high-rise office building located in Tokyo’s warm climate. The results of the experimental and numerical investigations are discussed to show the potential of photochromic films for window-retrofit applications.

As a result of global warming and environmental pollution over the past few decades, life on Earth has been adversely affected. For this reason, large-scale zero-energy buildings have garnered considerable attention for utilizing clean energy resources. Hydrogen is a green and sustainable fuel with remarkable features of having high efficiency, higher energy content than diesel and gasoline, and producing only water as waste. Hydrogen can be integrated with a hybrid renewable energy system as safe and reliable energy storage for a longer time in net zero energy buildings compared to batteries with short-time energy storage capability. The focus of this study is to find the optimum design for a hydrogen storage system to isolate a small lab building from grid power by providing its hourly energy needs with renewable resources located in Toronto, Canada. Hence, a model using TRNSYS software is developed to study the behaviour of an energy system that could supply electricity to the lab building. To conduct a case study, TRNSYS is used to extract the solar irradiance during one year for climate data of Toronto. The system mainly comprises solar panels, an electrolyzer, a fuel cell, and a hydrogen storage tank. According to the results, renewable energy system reliability can be increased throughout the entire year period, and grid dependency reduced by adding a hydrogen storage system. Based on the optimized simulation results the system can supply the load demands of the lab in a year with the solar panel electricity production and the hydrogen storage unit without requiring grid power.

Proposing new materials and systems to improve buildings' performance and energy efficiency often requires testing their performance in the field. Experimental performance characterization of new and existing building systems is crucial to understanding their behaviour. Full-scale experimental test cell facilities have been at the forefront of experimental performance evaluation in building-related research, as they provide a realistic representation of buildings, including environmental conditions, assembling challenges, and operational characteristics. In this paper, trends in the design and construction of outdoor testing facilities are first discussed. Then, based on the current literature and the knowledge gained through visits to multiple facilities, the new test cell facility “BeTOP”, located in Toronto (Ontario), is described. BeTOP is a full-scale experimental facility with the capacity to perform multiple experimental tests simultaneously. This paper describes its characteristics, including structure details, testing capabilities, system details, current monitoring campaigns, and future testing potential. The paper concludes by showing that the design of a full-scale testing facility is crucial to observe the long-term performance of new systems under variable boundary conditions in a continental climate with cold winters and hot and humid summers.

In recent decades, reducing the energy demand of the building sector has become a major goal of global policies. Proper design of the building-plant system is hence strategic to achieve nearly zero energy building (NZEB) target. This paper reports the results of modeling the building-plant system of an NZEB in Southern Italy. The case study is a multi-family complex of eight dwellings located in Bari, in the Apulia region. The building project originates from the energy refurbishment of a former industrial shed that was demolished and rebuilt for residential use. The planned HVAC system foresees the combined use of primary ventilation with fan-coil units fed by two ground source heat pumps (GSHP) supplied by eight vertical probes. Three hybrid ventilation strategies have been compared to evaluate the potential cooling energy saving: the first one examines an earth-to-air heat exchanger (EAHX), the second one proposes night hybrid ventilation from 10 pm to 6 am, and the last considers the adoption of free cooling in mechanical ventilation. Economic and energy comparisons among these three approaches are reported. Using EAHX, the cooling consumption saving reached about 20.7% The use of night ventilation combined with MVS can reduce the cooling energy demand for 14.4%, while free cooling in MVS produces a less effective decrease in the electricity consumption for cooling of about 7.7%. All three strategies generate major benefits in the middle-season.

Thermal performances of window frames and glazing represent a field of growing research efforts - worldwide - aiming to reduce energy consumption and achieve indoor comfort. A combination of newly designed super-insulated window frames and innovative glazing technologies may enhance the performance of windows. Aerogel-based “thermal breaks” for window frames, coupled with high-performing glazing, may lead to significant energy saving. In this work, yearly energy use for heating and cooling were assessed in several locations, for building models equipped with innovative technologies, for glazing and frames. The results of numerical simulations confirmed the opportunities offered by new technologies.

The renovation of old building facades should be performed mainly considering the building energy demand reduction. For this purpose, it is necessary to select retrofitted solutions that should be able of minimizing heat losses through walls. However, it is not only the nominal thermal transmittance that influences the amount of heat transported through the wall, but also the moisture content within the walls under in- service conditions. The main objective of this paper is the evaluation of the influence of the moisture content on the energy performance of retrofitted walls. A numerical study using the software WUFI Pro was carried out to quantify the influence of wind driven rain on the thermal transmittance of different wall assemblies exposed to different climates and orientations. This study reports the transient thermal transmittance of different retrofitted wall solutions as a function of moisture content.

The article presents the discussion on pandemic and the old printing company being replaced created some delays dedicated to aeroacoustics and engineering acoustics.