Solar water heating systems applied to highrise buildings-lessons from experiences in China

High-rise buildings have a significant impact on the surrounding environment.Building-integrated solar water heating (SWH) systems are effective ways to use renewable energy inbuildings. Impediments, such as security concerns, aesthetics and functionality, make it difficult toapply SWH systems in high-rise buildings.

At present, only China uses SWH systems on a large scalein such buildings. What are China’s experiences and lessons learned in applying SWH systems inhigh-rises? Are these experiences scalable to other countries? This study used a combination of fieldinvestigation, literature review and case study to summarize 36 systems that had been in operationfor 1–14 years.

System types, collector types, installation methods, types of auxiliary heat sources,economic performance and various basic principles were summarized. The economic performance ofSWH systems in high-rise buildings was analyzed and verified by a case study in Shanghai. Theresults show that the installation of SWH systems in high-rise buildings is feasible and reliable.Individual household systems (61%) were more popular than centralized systems (25%) and hybridsystems account (14%).

The average area of solar collectors per household was 2.17 m2/household,the average design solar fraction was 52%. Flat plate solar collectors (53%) was the most commonlyused collector, while electric heating elements (89%) were the most common auxiliary heat sources forSWH systems, followed by gas water heaters and air source heat pumps.

The cost of SWH systemsper m2 of a building area was between 22 CNY/m2to 75 CNY/m2. China’s unique practical experiencegives a reference for other countries in their efforts to make high-rise buildings more sustainable.