Case Study: nZEC - New construction of 84 dwellings in Largo Aldo Capitini, Sesto Fiorentino, Italy

Short Description

The development, set in the outskirt of Sesto Fiorentino in a green area, is part of a larger construction development for more than 600 living units, office premises, commercial spaces and recreational spaces.

Key Elements

Certification

Energy Class A for all the living units.

Project Management

All the materials being used are certified. Certifications have been verified by the Developer during the construction stage. The energy consumption monitoring started in 2010.

Capacity Building

The Coop. Staf is involved in educational programs to keep up to date with the sustainable design practices and energy certification. Unica has established collaborations with educational bodies such as the University of Florence and with energy supply companies.

Work with Residents

The householders received a booklet containing all the relevant information to use the flat ant the technical services correctly.

Thermal Insulation

In general, the thickness of walls is 30 to 50% more than commonly used in the area.

Heating and Hot Water

In this new development area, a tri-generation district network provides for heating, cooling and hot water. Fan coil units have been chosen to supply heat and cooling. Each flat has divisional meters for accounting own share of heat, cooling and hot water.

Electricity Saving Products

Energy saving bulbs has been used for the lightning of the external spaces.

Water Saving

Double flux toilet boxes, flux reducers installed at the water tabs.

Environmental Design

Some of the bioclimatic solutions adopted:

• Living spaces on the south side of the building;
• Ventilated roof cover;
• Increased wall mass thickness;
• Use of bioclimatic materials;
• Natural paints.
  
  
  

Funding

Energy efficient measures table:

Main Results

The monitoring for the period 2013-2014 points out energy savings of around 40%, since the building is now almost completely inhabited. Residents pay a fixed price for the energy supply service, which includes the running costs (energy consumption for heating / cooling and system maintenance). This implies that energy savings of 40% does not mean an expenditure reduction of 40%. However, annual average costs for the energy supply service are in line with those expected: energy costs are lower than standard building ones by about 10-20%.

Lessons learned

• Centralized Tri-generation System) works well if all the dwellings  are occupied, the partial use of the system can cause problems in the energy performance of the system.
• Since the system is very innovative, some management difficulties have occurred due to the inexperience of the company in charge of the energy supply service.
• Households  in general are not well disposed towards centralized systems, as they can’t directly regulate the temperature in the accommodation, and this trend was also replicated in this case. In the future Social Housing company will work for a greater involvement of the residents on this front in the preliminary stages through information and an adequate training.
• DHW production: according to the Social Housing company, should be paid attention to circulation, which, as in the case in question, undertakes to keep the water temperature 24 hours. Now the peak usage of the DHW can be foreseen, and this should be considered in  future projects . Due to the managerial difficulties incurred,  Social Housing company thinks it would be preferable to individual solution for the production of DHW leaving to each household choices of use: probably it would cheaper, surely easier to manage.
  
  
  

Additional Information

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