EXPERIMENTAL STUDY ON THE EFFICIENCY OF PELTON TURBINES FOR SECONDARY ENERGY RECOVERY IN WATER DISTRIBUTION SYSTEMS

Educational Research in Universal Sciences ISSN: 2181-3515 VOLUME 4 | SPECIAL ISSUE 13 | 2025 https://t.me/Erus_uz Multidisciplinary Scientific Journal October, 2025 9 DOI: https://10.5281/zenodo.17489004 EXPERIMENTAL STUDY ON THE EFFICIENCY OF PELTON TURBINES FOR SECONDARY ENERGY RECOVERY IN WATER DISTRIBUTION SYSTEMS Otajon Uktamov Master’s Student, Department of Power Supply and Renewable Energy Sources, TIIAME National Research University, Tashkent, Uzbekistan E-mail: [email protected] Ulugbek Alokhanov Master’s Student, Department of Power Supply and Renewable Energy Sources, TIIAME National Research University, Tashkent, Uzbekistan E-mail: [email protected] ABSTRACT This study investigates the potential of using Pelton turbines for secondary energy recovery in water distribution systems. The focus of this research is to explore how water height, flow rate, and load conditions affect the efficiency of Pelton turbines in such applications. A series of 8 experiments were conducted under varying conditions, including water heights from 3.17 𝑚𝑒𝑡𝑒𝑟𝑠 to 15 𝑚𝑒𝑡𝑒𝑟𝑠, and flow rates from 0.167 𝐿/𝑠 to 0.9 𝐿/𝑠. The results indicate that under optimal conditions, Pelton turbines can achieve up to 89% efficiency. Keywords: secondary energy generation, water distribution systems, pelton turbine, hydroelectric energy, energy recovery systems INTRODUCTION In modern water distribution systems, pressure-reducing valves (PRVs) are commonly employed to control water flow [1,2,7]. While PRVs serve their intended purpose, they lead to significant energy losses, which could potentially be harnessed by integrating renewable energy solutions. This paper presents experimental results from the application of Pelton turbines in water distribution systems to assess their potential for secondary energy recovery. Educational Research in Universal Sciences ISSN: 2181-3515 VOLUME 4 | SPECIAL ISSUE 13 | 2025 https://t.me/Erus_uz Multidisciplinary Scientific Journal October, 2025 10 EXPERIMENTAL SETUP A laboratory stand simulated real-world water distribution conditions. Measured parameters included: Water Height (𝐻): 3.17–15 𝑚 Flow Rate (𝑄): 10 𝐿 per trial, varied across runs Turbine Speed (𝑁): Rotations per minute (RPM), with/without load Load Weights (𝑚₁, 𝑚₂, 𝑚₃): Three load values tested Torque (𝑀): Measured via dynamometer. These data were used to compute output power and efficiency under different conditions [3,4,5]. CALCULATIONS 1. The water flow Q is calculated using the following formula [6] 𝑸 = 𝐕 𝐭 (𝟏) where 𝑉 is the volume of water (cubic meters), 𝑡 is the time taken (𝑠𝑒𝑐𝑜𝑛𝑑𝑠). a)Volume (𝑉1 = 10 𝑙𝑖𝑡𝑒𝑟𝑠) = 0.01 𝑚³, Time (t1) = 59.724 𝑠 b)𝑉𝑜𝑙𝑢𝑚𝑒 (𝑉2) = 10 𝑙𝑖𝑡𝑒𝑟𝑠 = 0.01 𝑚³, 𝑇𝑖𝑚𝑒 (𝑡2) = 33.864 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 2. Potential Energy Calculation The potential energy (𝐸𝑝𝑜𝑡 ) of the water is calculated using the formula [6] 𝐸𝑝𝑜𝑡 = 𝑚 ⋅ 𝑔 ⋅ ℎ (2) Where 𝑚 is the mass of the water (kilograms), calculated as 𝑚 = 𝜌 ⋅ 𝑉, where 𝜌 = 1000 𝑘𝑔/𝑚3, 𝑔 is the gravitational acceleration (9.81 𝑚/𝑠2), ℎ is the height of the water (meters). a) Height (ℎ1) = 3.17 𝑚, Mass (𝑚1) = 1000 ⋅ 0.01 =10 𝑘𝑔 b) Height (ℎ2) = 5.7 𝑚, Mass (𝑚2) = 1000 ⋅ 0.01 =10 𝑘𝑔 3. Output Energy Calculation The output energy (𝑃𝑜𝑢𝑡) is calculated using the following formula [6] 𝑃𝑜𝑢𝑡 = 𝑀 ∗ 𝑤 𝑡 (3) Where 𝑀 is the torque ( 𝑁 · 𝑚), 𝜔 is the angular velocity (in 𝑟𝑎𝑑/𝑠), calculated as 𝜔 = 2𝜋𝑁\𝑡, where 𝑁 is the rotational speed (in 𝑅𝑃𝑀), 𝑡 is the time (𝑠𝑒𝑐𝑜𝑛𝑑𝑠). 4. Input Power Calculation The input power (𝑃𝑖𝑛) is calculated as [6] 𝑃𝑖𝑛 =𝐸𝑝𝑜𝑡 𝑡 (4) 5. Efficiency Calculation The efficiency of the Pelton turbine was calculated using the following formula [6] Educational Research in Universal Sciences ISSN: 2181-3515 VOLUME 4 | SPECIAL ISSUE 13 | 2025 https://t.me/Erus_uz Multidisciplinary Scientific Journal October, 2025 11 𝜂 = 𝑃𝑢𝑠𝑒𝑓𝑢𝑙 𝑃𝑖𝑛𝑝𝑢𝑡 ∗100 (6) Where 𝑃𝑢𝑠𝑒𝑓𝑢𝑙 = Useful output power (calculated from torque and rotational speed). 𝑃input= Theoretical power input based on water height and flow rate. The output power was calculated as [6] 𝑃𝑢𝑠𝑒𝑓𝑢𝑙 = 𝑀 × 𝜔 (7) Where 𝜔 is the angular velocity of the turbine (𝑅𝑃𝑀). RESULTS The experiments were conducted for 8 different sets of parameters, where the results showed varying efficiencies for different water heights, flow rates, and load conditions. Below are the key results from the experiments. Table 1. Relationship between water head, flow rate and turbine efficiency. Experiment Water Height (𝒎) Flow Rate (𝑳/𝒔) Efficiency (%) 1 3.17 0.167 12.04 2 5.7 0.295 73.9 3 4.2 0.21 55 4 6.5 0.34 85 5 7 0.45 87 6 8 0.55 89 7 9 0.6 85 8 10 0.68 82 Efficiency increased with water head and flow rate, peaking at 89 % for 8 𝑚 head and 0.55 𝐿/𝑠 flow. Figure 1. Variation of turbine efficiency with water head and Figure 2. Efficiency trend curve showing optimal operating range Educational Research in Universal Sciences ISSN: 2181-3515 VOLUME 4 | SPECIAL ISSUE 13 | 2025 https://t.me/Erus_uz Multidisciplinary Scientific Journal October, 2025 12 However, after reaching an optimal point, efficiency begins to decline, especially at very high flow rates or mismatched load conditions. DISCUSSION Efficiency improved with increasing head and flow rate until an optimal point, after which mechanical and hydraulic losses caused a decline. Proper load matching was crucial for achieving high performance; excessive or insufficient loads reduced efficiency. The maximum efficiency of 89 % demonstrates the effectiveness of Pelton turbines for secondary energy recovery. CONCLUSION Pelton turbines can achieve up to 89 % efficiency in secondary energy recovery applications under optimal head and flow conditions. Efficiency declines beyond the optimal range due to mechanical losses or load mismatch. The results suggest that Pelton turbines can effectively contribute to renewable energy generation in water distribution systems. Future work should investigate long-term field performance. REFERENCES: [1] Meirelles, Gustavo & Brentan, Bruno & Luvizotto Jr, Edevar. (2017). Optimal design of water supply networks using an energy recovery approach. Renewable Energy. 117. 10.1016/j.renene.2017.10.080. https://www.researchgate.net/publication/320585043 [2] Plamonia N., Saputra E. R. A., Said N. I., et al. (2024). Penstock pipe’s hydraulic design for the mini hydropower plant at Besai Kemu, Bukit Kemuning, Lampung, Indonesia. 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Northern Technical University, Engineering Technical College of Mosul, Cultural Group Street, Mosul, Iraq. https://doi.org/10.1016/j.asej.2021.101684