Tensile Structures as Microclimate Modifiers

TS3 – Tensile Structures as Microclimatic Modifiers

What Materials are used in Tensile Structures?

• A tensile structure is a construction of elements carrying only tension and no compression or bending.

• Fabric for clothing was the first material used in tensile structures. Modern manifestations include other forms of fibrous material such as Fiberglass, Polyesters and Polymers such as ETFE.

• Such structures are classified as thin-shell structures since there’s only a thin layer of material separating indoors from outdoors TS3 – Tensile Structures as Microclimatic Modifiers

Thermal Flows On Thin-Shell Structures

• Thermal flows are important to any architectural design and have been for centuries.

• As an inhabited structure a Thin-Shell Structure must be a comfortable environment

• However, whilst the structural design can be approached with almost total confidence, the environmental performance of the spaces they enclose is still relatively poorly understood.

TS3 – Tensile Structures as Microclimatic Modifiers

Thermal Flows On Thin-Shell Structures

TS3 – Tensile Structures as Microclimatic Modifiers

Thermal Flows On Thin-Shell Structures

• The thickness of the fabric membrane, typically around 1mm permits the skin to function as a passive filter, capable of modifying both thermal and light levels within the enclosed space to minimise reliance on conventional energy sources to control the internal environment.

• Selection of materials with appropriate optical properties offers a means of creating spaces where daylight levels are accentuated or creating more protected shaded spaces.

TS3 – Tensile Structures as Microclimatic Modifiers

Use of Materials and Topology to Manipulate the Internal Environment

• Tensile structures can be used as microclimate modifiers in a number of different ways

• Selection of materials with reflective properties and strategically defined openings offer a means of creating spaces where heat can be retained, or dissipated within the enclosure.

TS3 – Tensile Structures as Microclimatic Modifiers

Example: Khan Satyr - Astana, Kazakhstan

• Temperatures in Astana can drop to -35 degrees Celsius in winter and climb as high as +35 degrees in summer.

TS3 – Tensile Structures as Microclimatic Modifiers

Example: Khan Satyr - Astana, Kazakhstan

• Temperatures in Astana can drop to -35 degrees Celsius in winter and climb as high as +35 degrees in summer.

• The three-layer ETFE envelope is designed to shelter the enclosed accommodation from weather extremes and to allow daylight to wash the interiors.

TS3 – Tensile Structures as Microclimatic Modifiers

Khan Satyr - Astana, Kazakhstan

• Temperatures in Astana can drop to -35 degrees Celsius in winter and climb as high as +35 degrees in summer.

• The three-layer ETFE envelope is designed to shelter the enclosed accommodation from weather extremes and to allow daylight to wash the interiors.

• A unique ventilation system utilizes buoyancy forces to drive hot air out of the structure in summer months, whilst retaining heat in winter months.

TS3 – Tensile Structures as Microclimatic Modifiers

Example: Denver International Airport, USA

• Temperatures in Denver can drop to -8 degrees Celsius in winter and climb as high as +30 degrees in summer.

• The two layer fiberglass envelope is designed to shelter the enclosed accommodation from weather extremes. The internal surface is highly reflective to prevent re-radiation of heat absorbed in the daytime to the night sky .

• A clever ventilation mechanism utilizes natural stack effect to effectively remove heat build up over warm periods

TS3 – Tensile Structures as Microclimatic Modifiers

Rules of Thumb to Microclimatic Modifiers in Thin-Shell Structures

• Every enclosed structure needs adequate levels of fresh air to ensure a healthy and comfortable environment

• Use low level openings on multiple orientations, combined with high level openings

• Use the natural form to drive ventilation airflow via natural means – i.e. stack ventilation

• Select the “reflectivity” and “transmissivity” properties of the tension material carefully, based on the local climate/microclimate

• Warmer climates should have large openings at high level combined with low reflectivity materials, to flush the heat out.

• Colder climates should have smaller openings at high level combined with highly reflective materials, to keep the heat in.

TS3 – Tensile Structures as Microclimatic Modifiers

THANK YOU !

Ioannis Rizos / AA Tutor