Determining the Optimal Opening for Multi Skin Facade with External Ventilation

Overview

Authors

Photo of Peter Simmonds

Peter Simmonds

Principal

Building and Systems Analytics

peter@petersimmonds.com


Keywords


Abstract

The envelope of the Harbin Bank Building in Beijing has a Multi-Skin Façade where the outer cavity is naturally ventilated. During the design the client raised some critical questions:

  1. What is the optimal size of the openings?
  2. How will outside air move through the outer cavity?
  3. If there is wind against the façade then the top and bottom openings will be equally pressured, so how will air still move through the outer cavity?

These points obviously concerned the client and the solutions had to be explained in plain and simple terms. This paper describes the design of the Multi-Skin Façade and explains with the aid of aero physics how the outer cavity functions under different external temperatures and different wind pressures against the façade. The result of the various investigations was an optimum ventilation opening for the outer skin.

Introduction

The project brief was straightforward: Provide 40,000 square meters of energy-efficient office space for Harbin Bank’s new headquarters in Beijing. What wasn’t so clear-cut was instruction from the bank’s chairman

Members Only

Background – The construction of the façade

As stated before the façade was to be aesthetically pleasing and fully functional, so the choice of glazing was critical. In order to evaluate the performance of the double skin

Members Only

The Alternative Façade Constructions

Alternative 1- MSF-1 consisted of the original GL-1 glazing and the original GL-2 glazing which comprised of 8mm YBE 0.138 (2#) + 12 mm Ar (Argon) +6mm clear glass

The Multi

Members Only

Method

Aero physics is not a discipline or term with which one is generally familiar in building, although it has played a role in construction for several years now. Aero physics

Members Only

Explanation

From the previous results we knew the climate façade performs well during the summer, the question arises whether the ventilated cavities are required to be closed during the winter months

Members Only

Conclusion

The methodology presented in this paper show how understanding the physics of multi skin facades can be used to prove the air movement through the cavity and the openings to

Members Only

Acknowledgements

Special thanks go to Russell Gilchrist of Gensler, who knew exactly what buttons to push in order to obtain the results he wanted.

Rights and Permissions

ASHRAE 2017. ASHRAE handbook - 2017 fundamentals. Atlanta: American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc.

ROOM - "A method to predict thermal comfort at any point in a space", Copyright OASYS Ltd. developed by ARUP Research and Development, London, England.

Simmonds P., 1991 "A Building’s Thermal Inertia", CIBSE National Conference 1991.

Simmonds P., 1991 "The Utilization and Optimization of a Building's Thermal Inertia in Minimizing the Overall Energy Use", ASHRAE Transactions 1991 V97 Pt2.

Simmonds P. et al. 2012, Tilted Glazing in building simulations and its effect on form refinement of complex facades simbuild 2012 Co-Author

Simmonds P. and Getov P, 2013, AIA Monterrey design Conference Epidermis/Hypothalamus: Building Envelope as a factor controlling occupant thermal comfort Co-Author

Simmonds P., 2013, 12th International Conference on Sustainable Energy Technologies Designing an intelligent building skin for occupant comfort

Simmonds, P., and Zhu, R., (2013) Stack Effect Guidelines for Tall, Mega Tall and Super Tall Buildings, International Journal of High-Rise Buildings, December 2013, Vol 2, No 4, 1-8

Simmonds P. and Getov P., 2013, Building Enclosure Sustainability Symposium 2013, Designing a Breathing Skin Co-Author

Simmonds, P., (2015) The new ASHRAE Design Guide for Tall, Supertall and Megatall Building Systems, ASHRAE 2015

Simmonds P., 2016, What are the heating and cooling loads generated from a high-performance façade? Façade Tectonics, 2016

Simmonds, p., and Gilchrist, R, (2018) Climate effects on tall, supertall and megatall buildings, Façade Tectonics, 2018

Tamblyn, R. T. (1991). Coping with air pressure problems in tall buildings. ASHRAE Transactions 97(1), pp. 824~827.

Tamblyn, R. T. (1993). HVAC system effects for tall buildings. ASHRAE Transactions 99(2), pp. 789~792.

Welty J.R., Wicks E.E. and Wilson R.E. 1969, Fundamentals of Momentum, Heat and Mass Transfer, John Wiley and Sons, Inc. New York.