15. Energy Saving Evaluation Based on Utilizing Recycled PET Bottles in Concrete Blocks in Iran

Nowadays, due to many advantages of PET bottles, their usage is increasing. In Tehran metropolis, the capital of Iran, because of unprincipled methods of collecting and recycling waste PET bottles, large amounts of them are left everywhere or separated illegally and turn into low-quality and contaminated flakes by unauthorized factories; therefore, finding a way to reuse these wastes can help reduce their pollution. This research is aimed to first evaluate all types of most PET bottles used by companies in Tehran metropolis and, second, in case of utilizing these recycled bottles in a 400 × 200 × 200 mm concrete blocks as standard block in building constructions, to determine the percentage of meeting the construction needs and the amount of reduction and consumption of energy and greenhouse gases caused by it compared to other common blocks. To reach the aims, all different most used PET bottles with 500 mL volume of water were collected from all hypermarkets in five main regions of Tehran metropolis, and the exact dimensions and volumes were measured in order to evaluate fitting eight waste bottles in each standard concrete block. Then, by comparing the number of blocks that can be made with total waste bottles with Tehran construction needs, the percentage of meeting the construction needs was determined. Eventually by calculating the rate of heat loss, the amount of energy saving and greenhouse gases reduction caused by it were determined. Results showed that total bottle concrete blocks meet approximately 71% of Tehran metropolis construction needs and they can reduce heat loss and greenhouse gases more than two times compared to common blocks. For further research, the energy saving can be examined by utilizing a combination of PET bottles and fibers in cement blocks.