Case Study: BIRD - Bioarchitettura Inclusione Risparmio (energetico) Domotica

Short Description

The technology used is that of dry construction with the highest levels of thermal insulation (class A CasaClima certification). All traditional power supply sources have been eliminated to achieve energy self-sufficiency from renewable sources. The energy requirement for heating, production of sanitary warm water and summer cooling is guaranteed by a system made of: geothermal system, heat pump, solar thermal, solar photovoltaic and regenerators of heat with efficiency > 75% for air renewal.

Key Elements

Certification

At the start of the construction work  energy certification was not yet obligatory in Lombardy, so an assignment of certification has been entrusted to CasaClima of Bolzano which, while the work was in progress, has led the inspection visits to verify the correct insulators’ laying and the elimination of thermal bridges. Within the certification blower door tests will be executed on 20% of the dwellings chosen by the certification authority and carried out by a third party specialized company. An agreement with ANIT for the monitoring of the buildings is undersigned.

Work with Residents

Given the system and architectural pecularity of the building, in the phase of delivery of the dwellings a simplified manual will be delivered and personnel of Aler will instruct the resdients on the correct way to use of energy management systems of the dwelling.

Given the profile of the tenants (elderly persons), the presence of a social concierge and four families of support is planned. Among their duties is helping the tenants use the energy management system of the dwelling correctly.  

Funding

Estimated cost: 6,6 million €

Financing sources:

- ALER funds or mortgage: 2,03 million €

- Lombardy Region: 4,00 million €

- Other: 0,57 million €

Thermal Insulation

The dry mortarless construction has the certain advantage of achieving a high thickness of insulation has been experienced without an enormous thickness of the walls. The U value of the covering is much inferior at 0,2 W/m2.K therefore than the limits required by law (DM 11.03.2008). The thermal bridges have been eliminated completely.

Oil-based insulation has been eliminated completely in favour of the use of natural fibres, particularly of wood wool, and it is widely used in the walls in order to increase the thermal inertia. The dry mortarless construction involves moreover the opportunity to proceed to life of the manufactured one, to the taking apart of the same one with the clean separation of the materials with the increased possibility of recycling the raw materials used.

Air Tightness

The air tightness of the building will be verified with blower door tests on 10  out of 52 dwellings.

Windows and Shading

To optimize solar contribution in the winter time, all windows face south.

They have also been fitted with electric rolling curtains to reduce solar radiation in the summer.

Ventilation

Every group of four dwellings is connected with a heat regenerator which supplies the intake and outtake of air (0,5 volumes per hour) with a heat recovery higher than 75%.

Heating and Hot Water

As already stated, the buildings are equipped with a complex system that combines geothermal probes of superficial type (spiral), heat pumps, solar thermal and photovoltaic. The energy balance for the summer/winter cycle and the sanitary warm water production should be equal between consumed electric power and that produced. The building would have therefore to be energy neutral or have zero emissions.

Main Results

It is too early to speak about results since the building site is in phase of completion and therefore of delivery to the future tenants.

The Class A certification by CasaClima on energy saving will guarantee a very low energy bill, mainly due to the energy system management. This aspect is decidedly important considering that the tenants will be elderly and  have a low income. Reducing the energy bill for these persons is equivalent to helping solve the problem of fuel poverty.

Lessons learned

We are waiting for the outcome of the tests from ANIT and the income of the tenants in order to estimate the effective behaviour of the dry mortarless construction, especially in the summer period. This aspect represents the greater unknown in the project, even if the presence of a low cost cooling system reassures us of the possibility to guarantee good comfort conditions for elderly people.