GENERAL INFORMATION

Residenza I Girasoli

Construction year: 2024

Climate zone: Cfa - Humid subtropical climate

via Giacomo Bulgarelli, Castenaso (Bologna), Italy

Architect

Ing. Luca Magri
Owner

Abitcoop

Architect

Ing. Luca Magri
Owner

Abitcoop

Residenza I Girasoli comprises two similar buildings, Pilot A and Pilot B. Both buildings are located in a rural setting and the aesthetic are similar to regional standards to ensure social acceptance. 

Large balconies are included in the design to increase need of outdoor living space.

Brick and concrete are the chosen materials for the structure.

Building gross area & Net area

929,92 mq (Building A), 722,21 mq (Building B)

Number of floors above ground and below ground

Pilot A: 3 floors, 6 dwellings and Pilot B: 3 floors, 7 dwellings

Average net area per dwelling

75 m2/dwelling

Types of outdoor and common areas

Green area, parking facilities

Charging station (yes/no)

Other relevant aspects

Large balconies are a unique feature of these new buildings.

aerial render plus energy building italy

Technology solution sets

Heating, cooling and ventilation

The HVAC & Domestic Hot Water (DHW), air heating/cooling and ventilation consists of a unit by Nilan EXRG system equipped with pre-tempering passive ground probe. AC as back-up system for heating, cooling and dehumidification.

Active energy efficiency solutions have been planned for thermal power generation and distribution, mechanical ventilation, smart shading systems and LED lighting.

Higher energy efficiency will be obtained from running logics that exploit synergies between systems, e.g., ceiling fans will work in combination with active cooling, and from user engagement by cloud-based HMS, i.e., user interaction.

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Building Technology	Type of System	Technology	Distribution System	Product Manufacturer or Company	Consultant
Primary Heating System	Decentralized	Air source heat pump Ground source heat pump	Radiator Air Other: Ceiling fan (Vortice)	Nilan, which was sold by EXRG (Treviso, Italy)	Ing. Agnese Ronchetti
Cooling System	Decentralized	Air source heat pump	Air Other: Ceiling fan (Vortice)	-	-
Ventilation		Balanced mechanical ventilation with heat recovery at building/apartment/room level Natural ventilation without opening automation		-	-
Domestic Hot Water	Integrated with the heating system			-	-

Renewable energy production

These renewable energy systems contribute to the buildings' Plus Energy status by generating a surplus of energy that can offset the building's energy consumption. The PV system produces electricity from sunlight, while the ground source heat pump provides energy-efficient heating and cooling by utilizing geothermal energy. The total energy per dwelling is 5.75 kWp, generated by panels that are installed with a 10 degree inclination.

roof photovoltaics plus energy building italy

photovoltaics plus energy building italy

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Electrical storage battery:

-
Photovoltaic rooftop system:

5.75 kWp (per each dwelling)

Energy Renewable Technology	System Type	Main PV Panel orientation	Total Installed Capacity (KWP)
PV Systems (KW peak installed, surface area, total or per m²)	Roof integrated PV system	East South-east Horizontal	34.5 kWp (total for Building B) 40.25 kWp (total for Building A)

Envelope technology

Building envelope

The building's envelope plays a critical role in making the building a Plus Energy, by minimizing heat loss during winters and heat gain during summers. The aim is to create a well-insulated and energy-efficient structure.

The building's envelope plays a critical role in achieving its Plus Energy status by minimizing heat loss during winters and heat gain during summers. EPS (Expanded Polystyrene) is used as insulation in the wall construction.

Wall	Material Used	U Value
Wall type 1	Poroton, EPS	0.165 W/m2K

Windows are designed to balance natural light and ventilation with energy efficiency. The use of sunshades, potentially automated systems, and good thermal insulation contributes to minimizing energy consumption for heating and cooling while maintaining a comfortable indoor environment.

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Window	U Value	G Value	Shading Type
Window type 1	1.0 W/m2K	51%	Sunshades
Window type 2	1.1 W/m2K	59%	Sunshades

Culture and climate

Opening windows and ventilation

Users tend not to open windows in well-insulated houses, and ventilation and dehumidification has been foreseen in these buildings to avoid mould formation.  Generally, users will cook frequently, thus extraction was accurately considered in the choice of systems. Also, humidity generated during cooking has been accounted for in sizing the ventilation systems.

Competences to manage systems efficiently

While certain systems e.g., radiant heating systems, are perceived as up-to-date and fashionable for a new house, thus users tend to add them among technical building systems, generally users lack the needed competences to make well-informed decisions due to their cultural backgrounds and/or previous experiences. Therefore, the focus on these buildings has been put on the possibility of customizing some final touches just before the delivery of the dwellings, while the installed technologies are not subject to changes or further customization by the users.

Culture Climate Survey

Discover more about cultural aspects

Peb tips for designers by designers

How to achieve successful Plus Energy Buildings

Advice on building technologies

Instead of bricks & insulation, walls in Ytong bricks (Ytong building blocks (xella.co.uk) will be preferred in future buildings, also for avoiding damages from icing/storms, and also because of simplified construction/on-site works.

Ceiling fans are useful in summer in the temperature range (>26 °C) which is also the minimum temperature allowed for indoor environment (despite this come from a criticized and tricky regulation).

Positioning ceiling fan and lighting is non-trivial. Ideally, light should be inside the fan or far away, to avoid flickering effect.

Ceiling fans are useful in avoiding air stratification, as the HVAC system works at low air flow rate.

In the dwelling, floor-floor heights have been reduced because of energy efficiency (less volume) but also to host air distribution and other systems. This does not come for free, and it requires complex design.

Some windows (and doors leading to balconies) have been replaced with more compact sliding windows. There, adding the shading can be done but it is tricky.

While having an Internet connection is nowadays common and accessible for all users, defining the IT infrastructure to allow a simple, robust, affordable middleware to link between cloud HMS, local gateways and local BMSs, has been a complex process which involved a number of professionals.

Climate and cultural adaptation

Not available for this building

Building certification process

The certification process is the standard for nZEB. The main issue there could be, in the future, how to define how much PV is "enough". This has an impact since the first design, and the building permit request.

Tools and software

Casaclima tool was used to calculate perfomance.

Cost optimisation

Anticipate problems at preliminary design stage, use standard and few selected providers and technologies (not necessarily on a cost criteria), because complexity is impacting the design and the execution. So, speed is favored, and costs are reduced.

Resident interaction

Needs of the residents will be assessed after the building is complete.

Performance challenges

Target building performance was plus energy. This made us change our standard electric HVAC system towards a full air system with the help of a geothermal system, ceiling fan and an high capacity photovoltaic system with batteries.

External services

Eng. Agnese Ronchetti (for HVAC system calculations). Schneider and EXRG (Eng. Stefano Faganello) for a design consultancy (for domotic and HVAC systems)

Policy barriers

Local regulation for new nZEB buildings was followed, without specific changes needed. The layout, with external units of HPs on balconies, should be carefully studied in advance, as late changes to structures (i.e. for hosting larger units) would imply new calculations and/or permit requests.

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