3for2 Beyond Efficiency

Main content

Category Building
Duration 2014 – ongoing
Funding Siemens Building Technologies
Key Partners

United World College South East Asia

TROX Technik GmbH

A/S Team

A. Schlueter, A. Rysanek, J. Pantelic, C. Miller, Y. Peng, P. Murray, F. Meggers (external collaborator, Princeton University)

Project Link



Conventional air-based cooling systems rely on large amounts of cold and dry air to be distributed throughout the building. Consequently, indoor climate control requires a lot of energy and extensive ductwork. In new commercial buildings in Singapore, up to one third of the enclosed volume is occupied by technical systems and structural elements, consuming valuable space. In 2010, as part of the Singapore-ETH Centre (SEC), the A/S Research Team started to investigate more efficient ways of providing a comfortable indoor climate. Our concept reduces space consumption by a third, at the same time, raising the comfort and increasing energy efficiency by a factor of two. Through systems integration we propose to build 3 floors in the space of 2 – hence 3for2. Eliminating the excesses of standard design, we achieve 2x the performance.

Our concept consists of three main components:

  • To split cooling and dehumidifying. Instead of using cold and dry air for both, we distinguish between removing heat from the building interior and removing moisture from the air coming from outside. Cooling can thus be achieved using much higher temperatures (up to 18°C) than those required for dehumidifying; separating these functions lowers the amount of electricity required.
  • To use water instead of air for heat transport. Water has a greater heat-transporting capacity than air, which allows for smaller pipes that can be easily integrated into the construction. Extensive false ceilings and floors to hide the technical systems become unnecessary.
  • To use small, decentralized ventilation units instead of a single central unit. These small units transport the air required for indoor air quality through the facade, dehumidifying it and blowing it into the room they are installed in. Air distribution through the building becomes unnecessary. The unit can be integrated into the facade or the floor.

All three measures allow a much stronger interweaving of service systems with constructive elements, freeing up space and volume thus offering both new design potential and economic opportunities. Comparing 3for2 to a standard “green building” in Singapore, our concept provides 20% additional office space, reduces energy consumption by 40% and requires 16% less construction materials. A first-time implementation of the concept is currently being realised on the campus of the United World College, Singapore.

detail of the 3for2 concept  
Details of the 3for2 concept
UWC exterior and interior view  
3for2 implementation at UWC Singapore: exterior view of slanted facade and internal fitout with chilled beams.

Selected Publications

  • Murray, Portia, Adam Rysanek, Jovan Pantelic, Matthias Mast, and Arno Schlueter. “On Decentralized Air-Conditioning for Hot and Humid Climates: Performance Characterization of a Small Capacity Dedicated Outdoor Air System with Built-In Sensible and Latent Energy Recovery Wheels,” Paper presented at the 6th International Building Physics Conference, IBPC 2015, Torino, Italy, June 2015.  E-Citations
  • Rysanek, Adam, Portia Murray, Jovan Pantelic, Forrest Meggers, Matthias Mast, and Arno Schlueter. “The Design of a Decentralized Ventilation System for an Office in Singapore: Key Findings for Future Research,” Proceedings of CISBAT 2015. Lausanne, Switzerland, 2015, 77-82.  E-Citations
  • Rysanek, Adam, Portia Murray, Clayton Miller, Jovan Pantelic, Matthias Mast, and Arno Schlueter. “Simulation Analysis of a Low-Exergy Decentralized Air-Conditioning System for Hot and Humid Climates,” Proceedings of Building Simulation 2015: Conference of the International Building Performance Simulation Association (IBPSA), Hyderabad, India, 7.-9. December 2015.  E-Citations
Page URL: http://www.systems.arch.ethz.ch/research/synergistic-buildings/3for2-beyond-efficiency.html
Thu Jun 22 16:15:33 CEST 2017
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