Extensive Green Roof Energy Savings

The green roof market is dominated by extensive designs with shallow growing mediums and deciduous plants that offer little potential for winter energy conservation.

Extensive green roof energy savings.

Green roofs are often compared to white roofs which are only used to reduce the amount of heat entering a building or to reduce the urban heat island in the summer 3. There are many different reported benefits that the addition of a green roof to a building can offer. 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. The breathable layer growing media on a green roof is also the basis for the well being of the plants and must be able to store water and air at the same time for a healthy growth.

Energy performance is a key benefit of green roofs. 15 to 50 per square foot. Therefore extensive green roofs especially with rubber crumbs as drainage layer can be a good tool for passive energy savings during summer periods in dry mediterranean continental climate. 8 to 20 per square foot.

During representative periods of heating demand december and january the electrical energy consumption of rubber crumbs and pozzolana cubicles. 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. The energy saving potential wh m 2 is calculated by dividing the difference of cooling energy between the respective reference model and the model with an extensive green roof added by the. Whilst green roofs are important for cooling cities as a whole a green roof can roof can also have a positive impact on the energy balance within any given building this is particularly relevant if a building has poor insulation and poor ventilation.

In summer the green roof protects the building from direct. The green roof growing media green roof soil is the breathable layer. One of these benefits is the potential for building energy savings where a green roof can reduce annual heating and cooling loads. Many studies have been conducted to assess the extent of energy savings possible with extensive green roofs.

There is only one difference. Both extensive green roof cubicles 24 show less energy consumption 16 7 and 2 2 respectively than the reference one 25 during warm periods whereas both extensive green roof systems present a higher energy 26 consumption 6 1 and 11 1 respectively compared to the reference cubicle during 27 heating periods. A 2006 study by the university of michigan comparing costs of conventional and green roofs showed that on average installing a green roof costs about 22 00 sq. Green roofs reduce the heat flux through the roof and less energy for cooling or heating can lead to significant cost savings.