Enhancing Marine HVAC Efficiency Through Free Cooling and Thermal Energy Storage: An Assessment in a Coastal City in India

Abstract

This study evaluates the potential of free cooling to improve marine HVAC efficiency under the coastal climate of Porbandar, India and examines the benefits of integrating thermal energy storage (TES) using phase change materials (PCMs). Analysis of hourly weather data for 2023 shows that free cooling is feasible for 45 % of the year, comprising 6 % (525 h) full free cooling and 39 % (3416 h) partial free cooling, which can reduce compressor load by 50 %. For a ship operating in harbor, this corresponds to annual fuel savings of 71,500 l, a reduction of 191.8 t of CO₂ emissions, and cost savings of ₹6.8 million. The highest potential occurs from November to February, particularly between the period 20:30 and 11:30, with over half of the air-conditioned hours during peak months allowing free cooling at a 27 °C supply air temperature set point. TES–PCM integration further reduces compressor load by 30 % and enhances onboard temperature stability. The methodology provides a framework to assess free cooling potential in other coastal regions and for ships at sea, demonstrating its viability as an energy-efficient, cost-saving, and sustainable solution for the maritime sector. The validation with real climatic data demonstrates measurable benefits in fuel consumption, emissions, and operational costs, underscoring both the scientific and practical significance of the findings in supporting sustainable and decarbonized maritime sector. This work is novel in extending free cooling and TES–PCM concepts, widely studied in buildings, to marine HVAC systems where research remains scarce.