5-3.THERMAL QUALITATIVE DIAGNOSTICS
1.MATERIAL OF BUILDING ENVELOPE
2.VENTILATION AND COOLING
1.The Material of Building Envelope
The building is designed with the double-skin facade. Both south and north are playing an unitized system with 240mm cavity between the two panes of glazing for the natural or mechanical ventilation, which can decrease the temperature of the surface close to the indoor environment.
With the Lowe coated glazing material, the exterior facade show a good thermal insulation. the smart blinds in the cavity are provided to shade the sunlight and avoid the glare ,especially for the area close to the window, which is automatic to change the angle with the change of the solar position and intensity.However, the shading device in the east and west facade, the glazing material is triple glazing which is the lowe frit glazing with the smart shading as well.
To maintain the low temperature of the interior glazing layer of the doubleskin facade, the radiant temperature need to be decreased which need to reduce the ‘operative’ temperature of the cavity in the envelop to improve the indoor thermal comfort and the usability of the areas close to the window.This system is particularly apply in the south and north facade, because the north facade is usually exposed to sun from west in the afternoon(figure 15)(psychological ,physiological and economical:The glazing material and the shading device ensure the visual quality , visual comfort and thermal comfort by avoiding the glare and controlling the sunlight penetration.
Fig.15 Air temperature at perimeter zones(Frechette, R E. (2009). )
2.Ventilation And Cooling
In the Pearl River Tower, the radiant cooling system is used for cooling instead of the normal HVAC system and ventilation strategies. Combined with direct outdoor air system and underfloor air system , the air indoor can be changed effectively and ensure the high quality of the indoor environment[3](Fig.9). By pumping the cold water in the pipe of ceiling , the metal plates in the ceiling and the metal fins of perimeter will be cooled to cool the indoor air for an ventilation effect, which can achieve the occupants’ thermal comfort and save large amount of the energy consumption.（Fig.10）
The doubleskin facade of the building is not only for the thermal insulation ,but also for the air ventilation, which can ensure the indoor temperature and satisfy the human comfort as a temperature regulator.(Fig.11)
(Physiological , psychological and economical: The technology adopted in the cooling system and building envelope is for a good ve ntilation and thermal comfort in the occupied space, which can maintain the indoor temperature and environment in a comfortable level.Also , with a good ventilation and comfortable temperature, the electrical consumption can be reduced.)
For the energy reduction, the cooling is share the largest part ,then the glazing material took the second place. Both daylight responsive controls and lighting are the effective design that they help the building save large amount of the energy.[Fig.12](Economical: effective daylighting strategies and cooling system are main designs to save energy consumption )
Fig.12 Radiant cooling coupled with under-floor ventilation(Fortmeyer, R. (2006))
Fig.13 chilled ceiling panel detail(Frechette,R.Gilchrist, R. 2008)
Fig.14 Indoor temperature with the double-skin facade[6]
The double-skin facade of the building is not only for the thermal insulation ,but also for the
air ventilation, which can ensure the indoor temperature and satisfy the human comfort as a
temperature regulator.(Fig.14)
It is a ventilation system called VAV system with 100% fresh air. All the bottoms of the
fenestration have small Apertures that it is used for deal with the air exchange. When the
indoor heat and waste gas make the temperature achieve 26 ℃, the VAV system will be
booted and output the fresh air to maintain the indoor comfort and human
health.(Fig.16,Fig.12)
Fig.16 VAV system with 100% fresh air(by group)
(Physiological , psychological and economical: The technology adopted in the cooling
system and building envelope is for a good ve ntilation and thermal comfort in the occupied
space, which can maintain the indoor temperature and environment in a comfortable
level.Also , with a good ventilation and comfortable temperature, the electrical consumption
can be reduced.)
For the energy reduction, the cooling is share the largest part ,then the glazing material took
the second place. Both daylight responsive controls and lighting are the effective design
that they help the building save large amount of the energy.[Fig.12](Economical: effective
daylighting strategies and cooling system are main designs to save energy consumption )
