Transition to the 4th generation district heating - possibilities, bottlenecks, and challenges

The 4th generation district heating (DH) will be available in the coming years. However, the transition from the current 2nd or 3rd generation DH is a challenging task. This article reviewed the technical issues associated with the transition: supplying low temperature to buildings, integrating various heat sources and thermal storages, and developing smart DH systems. Possibilities, bottlenecks, and challenges of the transition were discussed. The conclusion was that the transformation should be conducted carefully and gradually. Comprehensive consideration such as the energy status, system conditions, and operation customs must be taken into account. (C) 2018 The Authors. Published by Elsevier Ltd.