sunlight, daylight and shading

What happens if we control sunlight regardless of climate?

Reduces glare, prevents overheating, improves visual comfort, reduces cooling energy demand, improves indoor daylight quality and enhances building appearance

Explain the importance of controlling sunlight in a warm and sunny climate

Excessive solar gain can significantly increase indoor temperatures therefore increasing heat gain resulting in higher cooling loads, greater energy consumption and reduce thermal comfort.

Shading devices reduce Direct sunlight radiation before enters the building and lowest cooling demand which improves sustainability.

What are issues to consider when designing facade shading devices? Similarly linked to the general design recommendations

Building orientation, climate and latitude, solar geometry (solar altitude, azimuth and HSA/VSA), daylight availability, glare control, thermal performance, views and occupant comfort, maintenance requirements and architectural appearance

Explain the importance of controlling sunlight in a temperate climate

Diffuse skylight is usually the main source of daylight but still requires control of sunlight. Direct sunlight can still create glare, local overheating and uneven daylight distribution therefore solar control is still necessary to maintain comfort.

Explain the importance of controlling sunlight in a cold climate

Winter solar radiation can provide useful passive heating however south facing windows can contribute to reducing heating demand.

Shading systems should therefore block unwanted summer Sun and allow useful winter solar gain

What is the definition for glare?

Glare occurs when one area of a room is significantly brighter than surrounding areas

What is the definition for disability glare and discomfort glare?

Disability glare reduces visual performance and impaired vision but doesn’t always create discomfort.

Discomfort glare creates visual discomfort but doesn’t necessarily impair vision

What are the pros and cons of fixed external shading, variable external shading and variable internal shading

Maintenance free and good solar control but permanently obstruct skylight and can dominate architectural appearance.

Maximise daylight and flexible but requires maintenance.

Improves visual comfort but absorb solar radiation which can become the secondary heat source and depends on different users behaviours/comfort

What is the purpose for solar control glazing?

It has a lower light transmission, average Illuminance and peak illuminance compared to clear glass overall reducing heat gain and excessive brightness

What is the definition for electrochromic glass?

What is the definition for thermochromic glass?

Glass that changes transmission properties with applied voltage.

Glass that changes transmission properties due to heat

What are the benefits of smart glasses?

Dynamic control of solar gain, improved comfort and reduce energy demand

How do you calculate the shadow depth useful vertical shading devices?

The horizontal shadow angle is used for vertical shading devices

Sw =Pv tan(HSA)

Where Sw is the shadow depth and Pv is the width of vertical projection

How do you calculate the shadow depth useful horizontal shading devices?

The vertical shadow angle is used for horizontal shading devices.

Sh=Ph tan( VSA)

Where Sh is the shading height and Ph is the depth of horizontal projection.

What are the three orientation rules of thumb and give examples of the shading devices

For South facade, use horizontal shading devices like horizontal overhangs, awnings, brise soleil or recessed windows. This is due to the high summer sun angles which will be blocked effectively.

For an east/west Façades, use vertical shading devices like vertical fins, vertical louvres and recessed windows due to the low angle morning and afternoon sun that is usually difficult to block.

For North facade, usually requires limited sheeting such as vertical fins used in hot climates

What are some general design recommendation?

Fix overhangs effective on south facing glass, limit east/ West glazing, interior shading should not be relied upon for cooling reduction, shading strategies vary by latitude, light shells can reflect daylight deeper into spaces and computer simulations can optimise shading performance

What are some quick shading rules? Similar to the general design recommendations

Minimise east and west glazing, use horizontal shading on south windows, use vertical shading on West/east windows, if external shading is impossible use lower solar heat gain glazing and use light coloured Venetian blinds or translucent shades

Give examples of some case studies which use shading designs

High school, France- feature south facing classrooms and protected using 5 m cantilever perforated metal shading device devices to reduce direct solar radiation and prevent overheating.

City of Westminster College, London- which is horizontal shading on south side and vertical shading on East facade and the key idea is that different facade orientations require different strategies.

ArtHouse Apartments, London- features sliding louvres shutters to provide sun, privacy and thermal control in a user controlled environment so the dynamic shading can create a responsive facade.

Kierfer Technic Showroom, Austria- kinetic facade system, perforated aluminium panels fold and unfold and panels move on stainless steel rails. Purpose is for adaptive solar control and showcase metal fabrication capabilities.

Al Bahar Towers, Abu Dhabi- features dynamic facade inspired by natural systems and shading panels automatically open and close. This has the benefit of reducing solar gain, improving thermal comfort and reducing cooling loads.

Define climate adaptive building skins (CABS)?

List the technologies/components commonly used in them

What is the purpose/benefit?

High-performance kinetic envelopes.

Using sensors, micro processes, automation systems, actuators and responsive materials.

It improves building efficiency and uses real-time environmental responses