It included a solar-thermal collector (STC), thermal storage tank (TST), ASHP, sand-based thermal storage floor (STSF), and water pumps, with the floor containing pipes embedded in a 200-millimeter layer of sand for efficient heat retention.
“When solar radiation is sufficient, the sand absorbs a substantial amount of heat and releases it into the room,” the researchers say. “During period of insufficient solar radiation or at night, the stored heat is gradually released into the room, thereby extending the duration of solar heating.”
This not only enhances the system’s solar energy utilization but also significantly reduces the ASHP’s operating time in low-temperature, high-humidity conditions at night, ultimately boosting overall efficiency.