Thermal performance evaluation of an energy and environmental research center building during winter

The building is constructed on a ground area of 3300 m2 and consists of five floors of total area of 6361 m2 with an air conditioned area of 3351 m2. The heating system comprises 1577 evacuated-tube collectors, two accumulation tanks of 15 m3 each, two thermal storage tanks of 150 m3 each, two auxiliary boilers of 443,000 kcal/h each, pumps, heat exchangers and control equipment. The thermal performance evaluation shows that the inside temperature was kept at the desired value (22°C) which demonstrates the system's ability to meet the building load. The performance also shows that the collection efficiency for the whole season was 50% and the collected and stored energy was higher than the required load which indicates that the solar fraction to the load was 100%.