Sunny research! Sustainable building design with high energy performance for a modern commercial building

Status

completed

Summary

Objectives

Development of a sustainable over-all building concept by integration of following aspects:

• Merge of building design and energy performance
• Wellness in work with high flexibility
• Low energy-demand for heating, cooling and lighting
• Use of Renewable Energy to supply energy-demand

Methods

To collect data regarding demand of space, functionality and energy, different energy demand profiles were generated, employee questionnaires were developed and a functional diagram for the available space was established. Right from the beginning, architectural aspects as well as building services engineering were integrated into the process. Transient thermal simulation (TRNSYS) and Computational Fluid Dynamic simulation (CFD) were used for performance tests and optimisation.

The innovative design includes the following fields:

North/South orientation of the building:

• Active and passive use of solar gains by south façade
• High-standard offices in the north space
• Open, flexibly usable south space with greenhouse-puffer rooms

Innovative ventilation concept:

• Air handling unit provides north offices with high quality fresh air, natural overflow to south space
• Natural air flow on the south façade by thermal lift
• Ecological air humidification by light controlled plants in greenhouse-puffer rooms

Energy performance:

• Activation of thermal mass for comfortable radiant heating and cooling
• Configuration of south façade makes high solar gains by Photovoltaics and high comfort conditions possible without outside shading
• Heating and cooling demand will be provided with ground water heat pump and ground water heat exchanger

Results and Conclusion

Three main aspects regarding the deficits of standard buildings concerning "wellness in work" have already been defined in the proposal of the project.

1. Contrast and variety:
   The building's layout has a clear differentiation between North and South. In the northern part high-comfort single-offices are situated, while there is open space in the South - a large room only divided by transparent greenhouse-puffer rooms.
2. Light:
   The offices facing north reach a daylight-ratio of 3.8% (with horizontal metal fins for daylight redirection) while the south has 3.1% of natural light (without light redirection). Therefore both areas provide optimal conditions for office working places.
3. Comfort:
   • a. Fresh air: To the compact single-offices in the North fresh air is supplied by the ventilation system. The quality is high above standard levels regarding CO2 and humidity (The required air volume for the southern rooms is also brought in here). The southern area is an overflow-region due to the open arrangement. Transported by thermal lift air flows back along the south façade and then to the air handling unit for recovery of heat and humidity.
   • b. Humidity: the common problem of dry air during winter is solved by light-controlled greenhouse-puffer rooms for ecological humidity-conditioning in combination with humidity recovery in the air handling unit.
   • c. Radiant heat/cooling comfort: the majority of the heating demand and the entire cooling demand are satisfied by activation of thermal mass leading to comfortable radiant heat and cooling.

Optimal use of the available space could be achieved by comparing the area balance sheets. The resulting free space was used to support the concept of the two thermal zones in North and South.

In the southern zone vertical air chambers were integrated which are separated by glass walls towards the office area. Due to simulation results, the number of necessary greenhouse-puffer rooms could be reduced from five to three.

Due to the shape of the southern façade the following advantages could be verified by simulations:

• Optimised utilisation of the solar gains for passive and active use (Photovoltaics)
• Reflect of outdoor conditions and daylight
• High-quality working places, even without shading

Unlike conventional buildings, Sunny research! has no area without daylight, leading to a maximum amount of daylight hours and decreasing demand of artificial light.

Due to the use of opaque, highly insulated (U=0.23 W/m²K) ventilation openings, which are equipped with weather-protection fins and can be opened even over night and at any weather-condition, "free cooling" is made possible.

To avoid sound propagation on the southern façade a silencer is used, which was developed especially for Sunny research!. So, air can flow freely while at the same time a sound absorption of approx. 18dB. is achieved. To ensure perfect room acoustics sufficient sound absorbing elements had to be applied.

Advancing the building shell quality from low-energy standard to passive-house standard is only useful for parts of the building by thickening the insulation to 35cm and the use of windows with passive-house standard on the northern side to get an amortisation time of 7 years.

The concept's technical implementation required a high degree of problem solving in detail for certain tasks such as opaque ventilation openings, air and heat supply into the offices in the North, overflow opening North/South, internal flaps for "free cooling" etc.

Due to the fact that the use of PVC has to be avoided within the entire building, different constructions had to be created.

Regarding the expansion of the building, horizontal extension and internal changes are easy to do. Only an additional vertical extension requires complex planning. Flexibility and transferability were determined regarding depths of the building, axial grid and usability.

Energetic valuation

Compared to a current standard commercial building the primary energy use per m² useful area decreases by 80% from 245kWh/a to 54 kWh/a.

Project management

Ing. Anita Preisler, arsenal research
Integration of Renewable Energy

Project team:
ib hausladen (building services engineering)
arsenal research (CFD-simulation)
TU Graz - IWT (TRNSYS-simulations)
pokorny licht-architektur (lighting and daylight-simulations)
quiring consultants (room acoustics and noise protection)

Project or cooperation partner

• Arch.DI Ursula Schneider,
  pos architekten ZT KEG
  architecture

Contact

arsenal research
Ing. Anita Preisler
Faradaygasse 3, 1030 Wien
Tel.: +43 (0)50 550-6634
Fax: +43 (0)50 550-6390
E-Mail: anita.preisler@arsenal.ac.at