Architectural, structural and mechanical design for the project “Sustainable Pilot Program for Urban Neighborhood in the City of Ag. Varvara, Greece

The central idea of the project is the creation of an urban residential neighborhood of almost zero energy balance (nZEB buildings), with the application of energy saving techniques and systems and the integration of Renewable Energy technologies.
The purpose of the project is to improve the energy efficiency of the buildings in the under study area and to cover a significant part of their energy needs for cooling, heating, domestic hot water and electricity generation from renewable sources.

The building block is 3.150sqm and includes the 4 buildings we are going to study. Those apartment buildings are representative of the architectural typology of “social housing” during the 60s and 70s. In the center of the block we can find a continuous, outdoor, shared space. The buildings share a lot of characteristics such their as rectangle plan, every building has 4 floors and a basement, no building has an elevator.

Apartment buildings orientation

1st Building : Northwest – Southeast

2nd Building : Northeast – Southwest

3rd Building : Northwest – Southeast

4th Building : Northeast – Southwest

The site analysis consists of the following parameters :

SUN IN URBAN AREA

A series of simulations (with the 3d models of the buildings) were performed in order to study the exposure to sunlight in different parts of the facades. The chosen dates for the analysis were two solstices (21st of June and 21st of December) and two diurinals (21st of March and 21st of September).

For each chosen date we analysed the shading in the general urban area as well as in the directly adjacent surrounding area of the building.

Some general conslusions based on the results of the analysis are :

• Solar contribution to winter heating

The facades with a northwest or northeast orientation have intense lower thermal gain during winter

• Solar charges in summer

The facades are not adequatly equipped with shaders during the summer

• Renewable energy sources

The apartmens buildings’ shells are suitable for hosting sollar collection devices. The best suited facades for the installation of such devices are the southwest and southeast ones.

WIND

Most of the time the direction of the winds in the area remains the same. The study focuses on two representative conditions, summer and winter

• Winter Conditions

Winds with north, northeast  direction and with a speed of 4 m/s. The facades suffering the greatest exposure are the ones on the Str. Smirnis and Str. Sifnou. The outdoor space seems to be protected by the surrounding buildings with the exception of a negligible drift comming from the entrance of Str. Sifnou towards the Kolokithat Str.

• Summer Conditions

In this scenario winds are mostly northwest orianted and the facades with the greatest exposure are the ones on the Str. Kolokithta and Str. Voutenis. In this case the outdoor space is not protected by the buildings nearby, a fact that turns out to be positive considering that in this time of the year the maintenance of a cool space is of outmost importance.

THE BUILDINGS’ SHELLS

There are 4 buildings surrounding the space. All of them share common characteristics and none of them had thermal insulation on their structural elements, since they were build before the law that dictates so.

Later on the 1st and the 4th building were renovated and since they have external insulation, the window frames have been replaced and shaders have been added to the northwest facade. The buildings have central heating

The majority of the 2nd’s and 3rd’s building window frames are aluminium, with a few exceptions of wooden ones. The shading is achieved mostly with the use of tents on each apartment, which are in no good condition. There is no central heating.

BASIC CHARACTERISTICS

• Passive solar systems

For a bioclimatic shell the window frames need to be replaced with aluminium ones with double glass and shaders. For the facade a coat of thermal insulation is applied externaly. The thermal facade and the new frames upkeep the wanted temperature. The solar radiation is regulated by the use of steady or moving shaders, in order to protect the interior of the building from overheating.

• Active solar systmes

The space at the terrace of the building provides space for the installation of solar panels

• Landscape design for the outdoor shared space

BASIC DESIGN ELEMENTS

The first step was to study and assess the existing situation as well as the climatic conditions (sun in the urban area and the winds)

For the upgrade of the outdoor space the following points were considered

• To retain the natural scenery as much as possible (by keeping and enhancing the existing plantation)
• To retain the identity of the original space. This is achived by taking into account the public activities and habits of the group
• A simple design with clear routes and movements
• To stand out and highlight the central area of the buildings
• To use appropriate materials for an outdoor space bioclimatic design (meaning : the use of pavements with high reflectivity in certain points in order to avoid the accumulation of thermal energy, extended use of low planting and lawns to prevent from overheating, to incorporate water elements that will help with the cooling of the space especially during warmer periods of time, the enhancement of the plantation based on the needs of the space during every season)

LANDSCAPE – SURROUNDING SPACE

All the above elements were taken into consideration for the landscape design.

In the suggested solution the outdoor space takes a circular form. An arc like wooden shelter sets the limits and defines the building’s square.

BUILDINGS’ SHELLS

The facades are coated with thermal insulation, the window frames are replaced and the plaster that is going to cover the facades is light coloured in order to achieve the optimal reflection of the solar radiation.

For the 2nd and the 4th building, extended moving panels that cover the facades are used for shading.

For the 3rd building the shading is achived with the use of individuall (reversed L shaped) shaders on each window opening

For the 1st building, on the southwest facade, horizontal shaders in each opening are placed.