Seasonal sand-bed solar thermal energy storage in a region with extended freezing periods: Experimentally verified numerical simulation

In this paper, we report the comparison of the experimental results with numerical simulation. The numerical simulation was performed using TRNSYS. Fourteen weeks of data (January 28 to May 7) were collected and compared against numerical simulation results obtained using TRNSYS. For the 14-week period, the results showed that there was close agreement between the experimental measurement and the numerical simulation. The measured average temperature was 8.1 °C compared to the simulated average temperature of 8.6 °C. The measured maximum and minimum temperatures were 21 °C and −7.8 °C, respectively, while the numerical simulation maximum and minimum temperatures were 17.8 °C and −7.5 °C, respectively. For the five-year seasonal simulation, the system became fully charged by June 14. The maximum temperature the sand-bed achieved annually was 24.83 °C, occurring approximately on July 10, with a minimum of 11.1 °C occurring on January 24. The results demonstrate that sand-bed solar thermal storage systems are suitable for climates in regions with long periods of freezing temperatures which can contribute towards the net-zero energy status of a residential home. We reported the first experimental study, to the authors' knowledge, of sand-bed solar thermal storage conducted in a region with an extended freezing period carried out on a home situated in Palmer, Alaska, 61.6°N, 149.1°W [see G. Hailu et al., Energies 10, 1873 (2017)].