Abstract
Utilizing an efficient and reliable thermal energy storage (TES) bin in a concentrated solar power (CSP) systems can help to overcome the variability in the thennal energy supply due to the bad weather condition or during the off-sun period. At King Saud University (KSU), Saudi Arabia, a multilayered-wall TES bin has been developed to be used in a solid particle central receiver system. In this system, the multilayered-wall TES bin can reach a very high temperature and experience a thermal cycle. Therefore, the thermal expansion and compression will be significant which can cause cracks on the walls of the TES. One of the important layers used to avoid such a failure is the expansion joint layer. This research work attempts to further investigate various expansion joint materials for the TES bin, additional to the one which has been used in the previous design. Compression tests were conducted to fmd the suitable expansion joint materials. There were six (6) materials tested, i.e., asphalt, fibre, ceramar, sponge rubber, cork, and wooden fiber. Initially, room temperature compression tests were done. The room temperature tests were done in two stages, i.e., the preliminary stage and the advanced stage. The preliminary stage was a short test without cycling to quickly screen the prospective materials. The advanced stage was done to further test the best materials concluded from the first stage test. This test was done with longer compression holding -time and with cycling. The most promising materials from the room temperature tests were, then, tested at a higher temperature to simulate the real condition under which they will be utilized. The go/no-go criteria were how far the material recovers to its original thickness (referred to as the recovery value) and how fast after the compression it recovers (referred to as the recovery speed). The results showed that, at room temperature, sponge rubber has the highest recovery value and speed. However, at a higher temperature, all the materials have relatively low recovery values with the wooden fiber outperforms the others.