Green Roof Ambient

Year round green roofs can help to keep ambient temperatures around the panels at or near 25 0 c.

Green roof ambient. 1 3 these temperature reduction and energy efficiency benefits are a key contributor to the growing popularity of green roofs in the. Reduces greenhouse gas emissions. Therefore lower air temperatures on the roof improve the efficiency of heat rejecting rooftop hvac equipment because it is operating at a lower ambient temperature. A green roof assembly consists of a structural deck waterproofing system membrane and associated components and overburden with plantings.

Overall green roofs such as this are considered in credits toward leed certification due to their added benefit of minimizing possible building contribution to the heat island effect in urban areas. The green roof element provides the ballast to hold the a frames and panels in place. Likewise growing vegetation increases rooftop evaporation and transpiration rates and provides shade to the roof surface. Green roofs tend to maintain an ambient temperature of 90 degrees f creating optimal conditions for air conditioning.

Green roof temperatures can be 30 40 f lower than those of conventional roofs and can reduce city wide ambient temperatures by up to 5 f. 1 2 in addition green roofs can reduce building energy use by 0 7 compared to conventional roofs reducing peak electricity demand and leading to an annual savings of 0 23 per square foot of the roof s surface. 4 developing a uhi strategy addressing uhi requires investment in a variety of measures including white or reflective roofs green roofs urban forests and reflective paving. If implemented correctly green roofs can bring the rooftop temperature down to ambient which is the air temperature on that particular day.

Obviously painting roofs white increases solar reflectivity. If the air on the roof is made cooler by a green roof this process is easier and uses less energy. The extent of the green roof effect is related to the condition of the plants the position of the green roof and the ambient airflow condition. The green roof element can have a cooling effect especially in summer.

The roof system also serves to collect condensate in its troughs which is practical in a location such as houston where a typically hot and humid climate can produce a great deal of moisture. Whereas a conventionally dark roof basically bakes on a hot summer day transmitting the heat it absorbs to the building below a green roof can remain cooler than the ambient air temperature. So instead of the mercury reading on a roof pushing 150 degrees on a 92 degree day for instance the ambient reading will be closer to that day s temperature. It also has a waterproofing membrane to prevent moisture from entering a building or space.

A green roof makes the installation of a frame panels easier.