Case Study: nZEC - New construction of 20 dwellings in Via De Gasperi, Botticino Mattina, Italy (UNDER MONITORING)

Short Description

This Coop Casa sc House project in Botticino Mattina was completed in 2003. This building marks the beginning of the path of Coop Casa towards the construction of buildings with low energy consumption. The ultimate goal was to develop solutions to be adopted as construction standards for low environmental impact and high living comfort houses.

The location of this building was particularity suitable, as it was possible to place the main façade towards the south, free from shading, hence ideal in order to exploit the solar radiation, both actively and passively. Particular attention was given also to the economic aspects: construction costs were kept low, with no significant changes in relation to a building with "standard" features.

Key Elements

Thermal Insulation

Thermal insulation with external cladding, with polystyrene (EPS) panels 6cm thick, covering entirely the building envelope.

Thermal insulation of the flat roof with a double layer of polystyrene (EPS) panels for a total thickness of 10cm.

The structure of the balconies' overhang was interrupted, to allow the continuity of the external cladding and hence reduce significatly the thermal bridges.

Windows and Shading

On the southern façade, continuous balconies extend over the entire length, providing in summer an effective shading of walls and windows from direct solar radiation, but letting most of it in during the winter season when the sun is lower on the horizon and it contributes to a reduced need for energy for space heating.

A vertical shading system is installed over the balconies, consisting of several mobile wooden trellises, which can be moved according to residents' preferences; in summer it provides extra shading, while in winter it allows the solar radiation to reach the windows.

Environmental Design

The building is aligned on the east-west axis, with the main front facing south. All the apartments at first and second floor have a double exposition (three in the case of those at the far east/ west edges), to take advantage during summer of natural ventilation at night time, the best passive way to control overheating.

Heating and Hot Water

A central heating system with condensing boiler with nominal power of 80 kW, is sufficient to provide space heating and domestic hot water to the 20 flats.

The space heating is provided by mean of floor radiative system, technology which allows an excellent degree of thermal comfort with an space temperature of one or two degree less than when radiators are installed.

Each apartment is equipped with a unit for measure the thermal energy consumption for space heating (kWh), domestic hot water (m3) and cald water (m3). The monitoring system allows also measurement of the energy produced by the solar thermal centralized plant.

Electricity Saving Products

Dwellings have been provided with cold and hot water supply points for washing machines, in order to maximize the usage of the hot water produced by the solar panels. Some households have bought the washing machines with a double connection, which loads hot or cold water according to the washing programme selected, thus minimising the electricity consumption.

Currently, at least 8 different models of washing machines with double connection are commercially available in Italy, with or without the electrical heat-resistance.

Water Saving

Concerning water saving, the following measure have been implemented:

• a reinforced concrete underground tank of capacity of 35 m3 for the collection of rainwater, which is collected by a system of gutters on the roof and the solid components are filtered before storage. The water collected is used for irrigation of common green areas;
• WC with dual flush button 4/7 litres;
• installation of air-water mixers on the showers, which allows savings of up to 20% of water usage.
  
  
  

Monitoring

Click here to access the monitoring data on the HIVE Database!

Main Results

The building has been occupied since 2004. Coop Casa has been monitoring the energy consumption, which has confirmed the effectiveness of the energy efficiency solutions adopted: the energy need for heating is approximately 60 kWh/m2.year, while the overall cost for heating and domestic hot water is about €430 per apartment per year. These results are particulary interesting when compared to the average energy need for space heating in existing building in Italy, which is 140 kWh/m2 year.

Lessons learned

Thermal insulation means save energy: the builgings constructed by Coop Casa sc in Botticino have a progressively higher thermal insulation in order to contain heat loss in winter and so to encourage energy saving. It is very important to inform residents about the correct operation of thermal systems, especially in the case of floor radiant heating systems, where the "heat source", it is not physically identifiable and the response time (inertia) is much higher than in the case of the traditional radiators.

Additional Information

Ms Rossana Zaccaria
Legacoop Abitanti - The Italian Federation of Housing Cooperatives
E-mail: r.zaccaria@ancab.coop
Web: www.legacoopabitanti.coop