The project site, situated in Vienna’s designated “red zone,” is undergoing an exciting transformation from a former railway yard into a vibrant residential neighborhood. This redevelopment area already benefits from existing district heating infrastructure and will eventually comprise around 2,000 residential units. While most of the buildings are complete, some remain under construction, blending new architecture with renovated historic structures.
Advanced Hybrid Energy System
At the heart of the project’s sustainability efforts is a sophisticated hybrid energy supply system. This system integrates two district heating networks to optimize efficiency and meet diverse temperature requirements:
- A 3rd generation (3G) district heating network provides high-temperature hot water, essential for certain applications across the site.
- A cutting-edge 5th generation (5G) low-temperature network supplies space heating during winter months, significantly reducing energy losses.
The site also hosts Austria’s largest geothermal probe field, consisting of 500 probes that harness underground heat energy. Complementing this are rooftop photovoltaic (PV) installations with a combined capacity of 1,000 kWp, generating clean electricity on-site.
All residential buildings are equipped with floor heating and cooling systems. This design enhances the efficiency of heat pump technology, supporting both heating in the cold season and cooling in warmer months.
Summer Comfort Through Pre-Cooling
In addition to heating, the energy system offers a subtle yet effective cooling solution during summer. Utilizing the floor systems, the “pre-cooling” approach lowers indoor temperatures by approximately 2–5°C without the intense energy consumption of traditional air conditioning. While this method doesn’t dramatically chill rooms, it significantly improves comfort during hot weather periods.
A New Model of Social Housing
A large portion of the development is dedicated to social housing, but with a modern twist. Vienna has transitioned from traditional public housing models to nonprofit housing associations supported by public funds. These associations maintain regulated rents, balancing affordability with quality living standards.
The residential mix intentionally includes diverse income groups and household types—families, singles, students—to foster social integration and prevent segregation. Notably, students have recently been welcomed into these communities, further enhancing social diversity and cohesion.
Ownership and Energy Operation
The ownership landscape is varied, with nonprofit housing associations alongside private developers playing key roles. The entire energy system is managed by an Energy Service Company (ESCO), which handles investment and long-term operation contracts, typically spanning 20 years.
In this project, the ESCO named Green is wholly owned by the City of Vienna, exemplifying a strong public commitment to sustainable urban development and energy innovation.
