Direct Evaporative Coolers (DECs) have several advantages such as a user-friendly, cost-effective, small, and easy installation, therefore, they are frequently used for space cooling in hot and dry climates. DEC is a cost-effective system applied in residential or medium-sized buildings such as private offices and commercials; however, the gap of the system is higher water and energy consumption that are addressed in this paper. Water in a dry climate is vital and means life and greenhouse gases threaten lives on the earth. This research is an experimental method conducted for more than 2 years to develop a conventional DEC into a green-efficient system. The research aims to discover and reduce the water as well as energy consumption of DECs in a hot and dry climate. Energy transitions from fossil to solar is another aim of this research. Compared with the conventional sample in the developed prototype the water consumption was reduced by 23.8 liters/day (about 56%), and the operating hours of the system were also decreased by 55%. Currently, there are approximately 2.1 million DEC systems in operation in the case study city, so by applying the developed system, up to 6.2 million m3 of water can be saved in each warm period. The reduction of operating hours caused a reduction of 67.5W in electrical energy consumption per hour. In addition, by energy transition from fossil to solar electricity the in-operation CO2 emission of the developed system is zero. The implementation of this green cooling model will greatly reduce water and energy consumption and the developed model can be repeated and imitated in similar climates.
