DHW Storage and Recirculation Systems in High-Rise Hotel Buildings: A Comparison of Energy Efficiency and Environmental Impacts

This research examines high-rise hotel buildings located on the Mediterranean coast, focusing on the advantages, in terms of energy consumption and environmental benefits of installing domestic hot water (DHW) storage tanks on upper technical floors instead of in the basement. To this end, the Bali Hotel, the tallest hotel in Europe, is analyzed as a case study. The proposed system achieves a substantial reduction in energy consumption by decreasing heat losses in DHW recirculation pipes (61.3%). Annual energy costs are reduced by €8976.89, corresponding to overall DHW energy savings of 3.69%. In addition, installation costs are reduced by €15,462.18 due to the shorter recirculation pipe lengths required, which must withstand very high pressures exceeding 6 kp/cm2, reaching up to 18 kp/cm2. Although the initial installation cost is €15,462.18 lower, the elevated placement of the tanks increases maintenance and replacement costs. Therefore, after a 50-year service life, total construction and maintenance costs are €17,366.82 higher. This additional cost is recovered within 1.93 years, yielding cumulative savings of €527,106 over the building’s lifespan. Finally, the study quantifies the associated environmental benefits, demonstrating an annual reduction of 24,335.03 kg CO2eq in carbon emissions, a novel contribution to the existing literature on this topic.