Retrofit

Retrofitting Strategy	Application of vertical green wall and green roof
	Green roofs can lower the surface temperature of the roof which can reduce the heat conducted from the roof to the top floor to lower the energy consumption of the air-conditioning system. Green roofs can also lower the temperature of the surroundings and may reduce the heat island effect and improve pedestrian comfort. Reducing heating and cooling loads Reducing the size of HVAC equipment, insulating for sound, reducing storm water run-off, creating natural habitat, filtrating pollutants and reducing carbon dioxide out of the air. Can enrich biodiversity.
	Consideration
	Structural loadings and usage of the roof need to be checked. Overall heat gain study on façades by climatic simulation. Suitable plants and planting method should be well studied. Climber plants are preferred. Loading and waterproofing and fire safety have to be well checked and irrigation and drainage system should also be well designed. Maintenance method also has to be well studied before installation. Irrigation system, drainage and root protection should also be considered.
	Estimated Saving
	QOPAQUE = [AwUwaDT_EQ,V + ArUraDT_EQ,H]_PRE – [AwUwaDT_EQ,V + ArUraDT_EQ,H]_POST kW_FACADE = 1/COPQFACADEOPHR,yr where Aw, Ar = Opaque wall and roof area Uw, Ur = U-value or opaque wal and roof = 1/[Ro+Ra+(x₁/k₁+x₂/k₂+…+x_n/k_n)+Ri] a = outer surface absorptivity of opaque wall and roof DT_EQ,V, DT_EQ,H = equivalent temperature different of wall and roof (orientation) Green roof and green wall would reduce both the U-valve and absorptivity of the opaque wall and roof as well as the sol-air temperature different Please click HERE to view the list of terminology.