Carbon nanotube-based solar water heater with phase change material

Solar water heating (SWH) systems are an advanced renewable energy technology that have been extensively implemented around the world. For this project, phase change materials (PCMs) are incorporated into the SWH system to boost the evacuated tube collector's (ETC) heat accumulation. PCM facilitates a constant hot water output by allowing heat storage directly on the collector. Nevertheless, PCM lacks a sufficient heat transfer rate and suitable thermal conductivity and diffusivity, so carbon nanotubes (CNTs) are integrated for better energy transport. CNT sheets are an excellent medium for PCM and enhance the ETCs by enabling additional energy absorption. Upon transmission of an electrical current, CNTs are also a fast source of Joule heating. This allows the solar collectors to be electrically heated on days with insufficient sunlight, removing the need for a gas or electric booster. With these improvements, the evacuated solar water heater system's functionality and performance are significantly enhanced.