Experimental investigation of an IoT ‐assisted solar compression heat pump desalination system using a low‐ GWP R1234yf/R600a refrigerant blend

Abstract Passive solar stills produce 1–4 L/m 2 day, and their productivity rapidly decreases after peak irradiance. Also, most heat pump‐assisted desalination systems operate with the high Global Warming Potential (GWP) refrigerant R134a, despite global phase‐down goals. This study reports on an Internet of Things (IoT) based Solar Compression Heat Pump Desalination System (SCHPDS) with direct condenser‐to‐basin heat recovery, 30 mm granite sensible heat storage, bifacial photovoltaic power and ESP32‐Firebase cloud monitoring, tested in Coimbatore, India (10.95° N, 76.95° E). A low GWP zeotropic blend of R1234yf/R600a (70:30 wt %) was compared to R134a under identical operating conditions. The blend improved the system's coefficient of performance from 3.52 to 4.18 and increased peak basin and vapor temperatures, while decreasing both the discharge temperatures and pressure ratios of the compressor. Daily freshwater productivity improved from 5.50 to 6.81 kg/day, with thermal efficiency of 52.4%, exergy efficiency of 35.4%, gain output ratio of 0.91, and a 19.0% reduction in specific energy consumption. The total equivalent warming impact decreased by 34.4% and the effective GWP by 91.3%, satisfying the Kigali Amendment. The distillate met WHO drinking‐water standards (TDS: 85 ppm), and the IoT system registered 99.2% data reliability. With a production cost of INR 11.20 per liter and a 4.8‐year payback, the system is a low‐cost freshwater solution for off‐grid communities.