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Natural ventilation for tall buildings in China

Natural ventilation in high-rise buildings has received considerable attention globally, with experts from the UK, Hong Kong and China investigating acoustic, wind, façade and architectural aspects. Inspired by this trend, this research explored the use of natural ventilation in high-rise buildings in China, specifically.

We used case studies and leading-edge research from around the world, with the objective of producing a China-specific, market-focused proof-of-concept. Our research initially addressed the climate of Shanghai, with the potential for expanding the work to different climatic zones.

We undertook a multidisciplinary charrette to establish the base case, starting from a square tower with central core typical of Shanghai’s commercial developments. We optimised the CFD (computational fluid dynamics) simulation and used a detached eddy simulation turbulence model. The external CFD simulation helped us to understand the wind pressure coefficients on the façade and the wind traps as a function of varying external winds. The internal CFD analysis of the floor plate allowed the optimal size for the wind traps to be determined.

We also focused on options to extend the period of usability of natural ventilation by improving building energy performance through: improving the thermal performance of the envelope; reducing the internal loads; increasing the area of operable windows; providing exposed thermal mass for night-time purge; and providing external solar shading. This analysis was conducted using the Arup BEANS™ software suite and provided an insight into the comfort conditions of occupants during the natural ventilation period.

Natural ventilation cooling potential is significantly influenced by local climate, thermal properties of the building, occupant profiles and internal heat gains.  The research has established:

  • Best practice on naturally ventilated high rise buildings from Arup experts in acoustics, lighting, wind and façades
  • A new architectural high-rise typology that can be effectively naturally ventilated
  • Data linking occupant comfort in naturally ventilated spaces and increasing levels of building energy performance
  • Data on the proportion of the year during which purely natural ventilation is feasible in the specific climate of Shanghai.

 

 

This research serves as a resource for developers and designers seeking to incorporate natural ventilation into tall buildings. It demonstrates the proof-of-concept and the technical and environmental feasibility of natural ventilation schemes in China.

 

 

As a component of a low-energy high-rise office development, natural ventilation has the potential to contribute to reducing peak energy loads. Reduced energy loads present numerous commercial benefits to clients, including:

  • smaller central plant, and reduced capital expenditure
  • reduced building running costs, and more competitive rents
  • increased nett-to-gross ratios by eliminating air plant service floors, and replacing them with smaller, on-floor air plants for use on days when natural ventilation is inappropriate
  • potential to capitalise on green credentials, and improve public image.