The building is located in a residential area in the municipality of Marousi Athens. The block consists of three office buildings from which the east building is the A.N. Tombazis and Associates Office Building.
The total building area is 1100 m2. The design is developed in three levels, and basement with parking area.The two long sides of the Office Building are facing east and west. For reasons of bioclimatic design, the building is narrow and long, approximately 8 x 35 m. Thus all workspaces are adequately supplied with daylight through side windows. As many as possible of the mature olive trees that existed on the site have been saved or transplanted. An important feature of the landscaping is the pond, a sculpture by G. Zongolopoulos and the wooden decks that lead to the entrances of the buildings.
The interior of the building is one open space developed on three split level decks interconnected at two points by two open steel stairs with wooden treads that have been designed in such a way, so as to provide minimum visual obstruction. Metal trusses support the concrete slabs of the different levels of the building. In order to combine the structural and mechanical depth and increase the perception of openness of the interior space, metal trusses support the concrete slabs of the different levels of the building. Outdoor indoor climate
Average ambient temperature:
Global irradiation: 1581 kWh/m2
Sunshine hours: 2818 h
The present office building is an interesting example of a well designed building from architectural and energy point of view. The shape and the orientation, as well as, the interior planning of the building (it is an open space) give the possibility to exploit the local climate for energy conservation and daylighting purposes. The installation of a BEMS gives the possibility to control all the systems (such as ceiling fans, night ventilation fans, etc.) installed in the building as well as to monitor energy consumption. The building is also equipped with 7 split and 2 single package air-to-air heat pumps for cooling and heating purposes (back up system). Rainwater is collected and used for irrigation and flushing of the double mode toilets.Passive Design Measures
The shape of the building and the location of the workstations, near the windows, allow an efficient use of the daylight. The building is entirely daylit from both sides by windows and from the roof by way of clerestories. Also, these clerestories are equipped with reflective curtains (Figure D-1) in order to distribute the daylight “deeper” in the building.
- The building including most of the basement is naturally lit by means of sill to ceiling windows that area provided on both long east and west facing facades and clerestories above the two stair wells.
- The east- and west-facing windows are provided with exterior fabric awnings positioned at approximately 15 cm from the wall, which provide both shading and glare control.
- The south-facing clerestory is provided with a light shelf on the south side.
Ceiling recessed downlights and task lighting compose the artificial lighting system. Artificial lighting is used only in case natural lighting is not adequate. The control of the artificial lighting system is manual on/off.
Another important element of building is the shading devices. They are exterior blinds for the windows and interior blinds for the skylights. The material is white plastic cloth, and its height can be adjusted, through a rotation mechanism. On the last level of the building, skylights are constructed, in the middle of the ceiling. They are covered with panels of cloth, which hang from the roof.
Ventilation and Cooling
Special attention has been paid to a combination of natural ventilation and passive cooling with mechanical ventilation. A central unit controls the system. In this region, the heating and cooling loads of an office-building normally cause high electricity demand. The following extra measures are taken:
- Natural cooling is achieved by evaporative cooling due to the presence of vegetation and water pond, by solar protection of the building shell and by cross ventilation.
- Ventilation and cooling is achieved by cross-ventilation, when appropriate and by automatically controlled ceiling fans, which extend the comfort range from 25°C to 29°C. When temperatures exceeds 29°C a zoned all-air heat pump back-up air-conditioning system turns on.
- Cooling is further enhanced by radiation by the mechanical night ventilation provided by two extraction fans on the roof, which by way of the lower night time exterior temperatures provide a temperature drop of about 3°C the next day.
- The thermal mass of the building is very high.
The exterior of the building is clad with fair-faced cement bricks and has increased 10cm insulation. The U-values of the ground floor, roof and external walls are 1.41 W/m2K, 0.45 W/m2K, and 0.40 W/m2K respectively.
Acoustics have been given special attention due to their importance in the large open interior space. Metal acoustic panels are suspended from the concrete decks of the different levels in an open configuration that allows for movement of air between the panels and ceiling.
Measurements for a full year (April 1996-March 1997) show the following results: The overall consumption (heating, cooling, lighting, night and day ventilation and equipment) is 90.1 kWh/m2. The total consumption for heating is 35.7 kWh/m2 and 4.7 kWh/m2 for cooling. The energy consumption for lighting is 3.1kWh/m2 which on average represents 3.5% of the total energy consumed. A large amount of energy 24.7kW/m2 is consumed for PC’s. As the building is properly designed to reduce the energy consumption for cooling, this parameter represents only the 5% of the total energy consumption. Additionally, the energy consumption for the artificial lighting system is also low (4%), a proof of the right natural lighting design of the building.Financial data
The total construction cost was 1000000 Euros