Technical & Economical assessment of the interconnection between façade integrated solar thermal system and low temperature district-heating.

This paper explores the techno-economic viability of coupling unglazed solar thermal façade system with a low temperature district heating network. this concept allows a more efficient control strategy for heat is allowed, where direct solar heat and heat from district heating are alternated in order to maximize the efficiency of the whole system. ST heat is directly used in the building when there is underproduction and when ST overproduces, this system allows to take profit from the network for the delivery of the excess heat. The use of unglazed collectors for low-intrusive architectural interaction in façades is discussed. Each system separately have proven efficiency, however, the most novel part of the study is finding a method which permits de combination of both technologies, proposing technical solutions and economic studies. Unglazed system reach thermal efficiency up to more than 30% in reference of the total radiation in the south façade, which are similar to other high efficiency solar systems. As for the economic results, it has been made an economic assessment at mid-time sight and positive economic meters have been achieved. Moreover, economic results from simulations prove the viability for unglazed solar district heating when integrated massively in facades