Frequently Asked Questions

Why to maximize RES (Renewable Energy Sources) harvesting in buildings is required?
Buildings are the largest energy consumers today in Europe (40%) and one of the largest carbon dioxide emitters (36%). Improving energy efficiency and integrating Renewable Energy Sources in buildings are two key strategies to implement in order to meet the ambitious goal of carbon-neutrality by 2050, set out in the European Green Deal. Within this framework, the EnergyMatching project develops new concepts and technologies to optimize the interaction between buildings and energy systems to maximize the RES harvesting in the buildings.

How can I use the contents and results of the EM platform?
In general, the EnergyMatching Platform aims to support the integration of adaptive and adaptable envelope RES solutions for energy harvesting in buildings. In particular, an optimization tool helps you in the preliminary design of your BIPV system, taking into account different aspects (techno-economic, energy and environment-related). A repository of BIPV and Solar Window Block configurations would inspire and support you in the integration of active building skin solutions in buildings, providing an insight into their expected performance. Finally, a showroom of technologies available on the market, with direct contacts to the related manufacturers, links you to the industry actors. Click on the "Can we help you?" button and discover the contents that can help you in your business.

I’m interested in taking part to the Marketplace section, is it possible?
Please contact the EnergyMatching Platform developers at Eurac or R2M.

What is BIPV?
BIPV (Building Integrated Photovoltaics) are photovoltaic systems that are seamlessly integrated into buildings as part of the roof, façade, or other components. For more information, please see the “BIPV basics” and the “EnergyMatching Catalogue”.

What does it mean to optimize the BIPV system?
The EnergyMatching Tool supports the early stage of BIPV design, suggesting the optimal capacity and position of the photovoltaic modules, and the optimal electric storage capacity, according to the case study specificities and the objective set in the optimization. For this reason, the EnergyMatching Tool differs from common design approaches that usually set PV and electric storage capacity at the beginning and then run several simulations to find a suitable configuration.

Does the EnergyMatching Tool evaluate different photovoltaic technologies simultaneously?
No, just one photovoltaic technology (module size, efficiency, cost) can be considered in the optimization.

Does the EnergyMatching Tool take into account any electric storage?
Yes, the tool can optimize the electric storage capacity as well as the PV modules dimensions and position. If you don’t want to consider it, just select “No” at the question “Optimize also the battery capacity?” in the input form.

Does the EnergyMatching Tool evaluate photovoltaic modules with shapes different from rectangular?
No, the tool works with rectangular photovoltaic shape only. It automatically divides in rectangles (with dimensions set by the user) the areas available for PV installation. For more instruction, see how to design the "Areas available for PV” here.

How does the EnergyMatching Tool calculate the irradiation?
The irradiation is calculated using the ray-tracing method (find detailed information on the public report “EnergyMatching (EM) Tool for optimization of RES harvesting at building and district scale” that can be downloaded here). The “Areas available for PV” are subdivided into a grid of smaller rectangular surfaces, the centroid of each becomes a node in a measuring grid. The irradiation on each node for each time-step of the simulation is calculated using the Radiance reverse ray-tracing engine (see the Radiance manual here). The output is an irradiation matrix, i.e. one of the inputs of the EnergyMatching Tool optimization algorithm.

How long should I wait to get results of my BIPV optimization?
It depends. Many inputs have influence on the computation time, i.e. dimensions and number of the surfaces available for PV installation, time horizon set for the evaluation, PV module dimensions. The number of optimizations launched is also relevant. The optimizations are processed one at a time.

What should I do if the BIPV optimization does not work?
Check your inputs in the “EnergyMatching Tool” page – Your optimizations. Check if the required geometries (i.e. “Area available for PV” and “Context”) and files (e.g., “Weather file” or “Electric demand profile”) are constructed in the right way, as explained in the documentation provided within the tool input form.

Where do the BIPV case studies come out?
The BIPV case studies section collects results of optimizations performed using the EnergyMatching Tool. When users run the tool, they can decide whether to keep the optimization private or to publish it in the BIPV case studies section.

What is a Solar Window Block?
A Solar Window Block is an autonomous prefabricated window system that integrates an insulating frame, a highly efficient window, a PV module, a shading system and a decentralized ventilation machine. The energy produced by the PV module and stored by a battery is used to feed the ventilation machine. For more information, please see the “EnergyMatching Catalogue”.

Could I evaluate the performance of a Solar Window Block configuration in different locations?
Italy, France and Sweden are the available locations, as they are the locations of initial demo cases within the EnergyMatching project and therefore the ones considered in the simulations run. No more simulations can be run.

Which are the main differences between the three Solar Window Block configurations?
The main difference between them is the BIPV integration on the window sill, as an overhang or vertically. However, this different PV integration implies some other important differences:

Which is the baseline for the basic thermal performance?
The baseline used to compare the Solar Window Block thermal performance is a standard window (Frame dim = 0.12x0.12m, Uframe = 1.3W/m2K, Ψinstallation = 0.2W/mK). The parameter compared is the annual heating demand per area for both windows (standard window and Solar Window Block) under same boundary conditions.

Which is the baseline for the energy production-consumption matching?
The baseline value of the actual ventilation machine working hours rate is a minimum threshold of 80%. This working hour rate of 80% has been chosen because it ensures acceptable indoor CO2 concentrations in most of the cases analysed.

Which is the baseline for the daylighting?
The baseline value of the daylight factor is a minimum threshold of 2%, which is the general recommendation for residential buildings.

Why the BIPV overhang heating demand results lower than the other configurations and the overheating results higher than the other configurations?
The heating demand is lower for the BIPV overhang due to its better thermal performance (Uw installed=0.8 W/m2K). However, its more external position results in receiving more direct radiation, as the glazed part is less shaded by the surrounding walls. Even if the presence of the BIPV overhang compensates slightly this issue, it still results in higher overheating events than in the other two cases, under certain boundary conditions.

Which is the ventilation rate of the ventilation machine?
The calculations are performed based on a commercial decentralized ventilation machine that supplies/extracts air with 5 different fan speeds with the corresponding airflow rates: 15, 20, 30, 35 and 42 m3/h. Different ventilation hourly profiles were created to assure acceptable indoor CO2 concentrations, depending on the type and occupancy of the rooms. Annual ventilation machine consumption is calculated based on these theoretical ventilation machine hourly profiles.

What does the working hours rate indicator mean?
This indicator is a ratio between the annual hours in which the ventilation machine is actually working thanks to the energy supplied by the PV and the battery, and the annual theoretical working hours in which the ventilation machine should be working based on the predefined use schedules. It gives an estimation of how many times the PV and battery system are not able to supply the power to the ventilation machine and therefore this cannot work as expected.