The researchers compared an optimized underground passive solar greenhouse model with a conventional one to see which performed better in terms of indoor air temperature, sunlight exposure, and energy usage. The optimized model had 30% lower heating needs than the conventional model. The average air temperature in the optimized greenhouse ranged from -4 to 33.1 °C, while the conventional one ranged from -8.4 to 24.7 °C. The maximum monthly heating requirement in the conventional model was 796 MJ/m2, while the optimized model only needed 126 MJ/m2. The TRNSYS model used had a high predictability rate of 95.95%.