Abstract

In Korean apartment buildings using district heating, centralized DHW (domestic hot water) systems are recommended to maintain a supply temperature of 55 ℃ to prevent Legionella growth. This increases energy consumption. To address this issue, the application of HIU(Heat Interface Unit)-based individual DHW systems has been increasing in Korea. This study evaluated the effectiveness of the HIU-based individual DHW system by analyzing DHW energy consumption and pipe heat loss characteristics under summer conditions. Simulations were conducted for a single housing unit in the upper floors of an apartment building under the operating conditions of each system. The results showed that the centralized DHW system reduced the risk of Legionella growth by maintaining the return water temperature above 50 ℃. In contrast, the HIU-based individual DHW system could reduce the risk of Legionella growth because DHW was directly generated within housing unit. In addition, the HIU-based individual DHW system demonstrated the potential to improve energy efficiency by reducing DHW energy consumption and pipe heat loss.