District energy network (DEN), current global status and future development

The conversion of fossil fuel energy into usable and sustainable energy for resilient urban development is the challenge that defines our commitment to our natural habitat. The ever increasing population of the metropolitan area has boosted the demand for energy, on the other hand, the price of traditional fuel sources has shown sharp fluctuations during the past decade, all this is happening at the same time that climate scientist has warren about the near future disaster due to climate change. This situations challenges governments, policy makers and organisations around the world to come up with a solution that is secure, safe, environmentally benign, flexible, renewable and stable. One of the promising technologies that can tackle most of the boxes, is the district energy network. The integrated system can provide required energy, either as electricity, heating or cooling, by utilising available local energy/waste resources. The integrated thermal storage facility would ensure secure and stable access to energy all daytime. A sophisticated and intelligent algorithm that links the potential demand to the supply, using user behaviour analysis and meteorological data ensures the flexibility of the system and defines the next generation of district energy networks (DEN). This work has focused on different district energy network technologies, their applications, configuration, and has extensive information about the existing systems around the world. Finally, the future direction and research gaps are concluded from this review work.