Reducing pumping energy in thermal grids: A study on hydraulic modeling and design approaches

This study investigates the hydraulic modeling of district heating and cooling systems to reduce pumping energy consumption. Key parameters such as head loss, pumping power, pump cost, and piping cost are calculated through hydraulic modeling in Python, integrated with TESSA, a validated spatial energy planning digital toolbox for district energy systems. The model first evaluates the impact of pipe size on system performance in both single-pipe and double-pipe configurations. Sensitivity analysis and Monte Carlo simulations are then applied to assess key parameters across urban, suburban, and rural cases from Switzerland. The research also compares the advantages of pressure loss and velocity limit approaches to pipe sizing, examining flow velocity limits, head losses, and the impact of undersized or oversized piping on energy efficiency and system resilience. The results indicate that oversizing pipes reduces the risk of water hammer while ensuring system adaptability for future building connections. Furthermore, total-order sensitivity analysis reveals a higher sensitivity to pipe size compared to the percentage of connected buildings. Monte Carlo simulations suggest that urban areas allow for system design with fewer initial connections compared to rural areas, offering greater flexibility for future expansion. This indicates higher adaptability for connecting additional buildings in urban areas than in rural areas. • Hydraulic modeling reveals potential for significant reduction in pumping energy. • Double-pipe system is preferred due to fewer heat sources at a comparable total cost. • Oversized pipes enhance system adaptability but somewhat increase the cost. • Sensitivity analysis shows that pipe size significantly impacts system performance. • Monte Carlo simulations show rural areas face higher risks from demand growth.