A laboratory scale heat pipe condenser with sweating boosted air cooling

摘要

Air-cooled condensers (ACCs) in thermal power plants are more competitive than the water-cooled condensers (WCCs) in addressing the global water crisis. The state-of-art ACCs need emerging heat transfer enhancement technologies, so hybrid wet/dry cooled condensers (HCCs) are employed to compensate for the low efficiency of ACCs. We propose a heat pipe air-cooled condenser (HPACC) to overcome the high capital and operating cost of traditional HCCs. HPACC combines the proven heat pipe technology with a novel sweating-boosted air-cooling strategy. Its architecture is similar to the most efficient once-through WCCs, but replacing conventional water tubes with high-performance heat pipes. A laboratory scale HPACC is built by scaling down the prototype of the proposed HPACC. This study evaluates the heat transport and rejection process within an HPACC. The thermal performance of HPACC is characterized under various heat loads and air velocities, and the sweating-boost effects on the HPACC are investigated. Our study shows that a saturated heat load on the HPACC exists under given air-cooling conditions. The minimum overall thermal resistance of HPACC is 4.7439 x 10(-2) K/W achieved at an effective heat load of 1606.40 W with an air velocity of 3.0 m/s. Air cooling is further boosted by the sweating process on the fined surface integrated with superwetting copper hydroxyl nitrate wicks (Cu-2(OH)(3)NO3). It demonstrates that HPACC with a sweating-boosted air cooling (HPACC-SB) significantly improves the total effective heat load by 172.17% and reduces the overall thermal resistance by 64.27%. The proposed HPACC is promising in replacing current cooling equipment of thermal power plants. Moreover, substantial water savings will help alleviate the water crisis facing the world.