Open Access

ARTICLE

Energy and Exergy Analysis with Heat Exchanger Network Optimization of an Indian Dairy Industry

Kiran A. S.¹, Dayakar G. Devaru^1,*, Mohan N.², Bhaskaran Gopalakrishnan³
1 Industrial & Production Engineering, SJCE, JSSSTU, Mysuru, Karnataka, India
2 Electrical and Electronics Engineering, SJCE, JSSSTU, Mysuru, Karnataka, India
3 Department of I and M Systems Engineering, West Virginia University, Morgantown, WV, USA
* Corresponding Author: Dayakar G. Devaru. Email:

Energy Engineering https://doi.org/10.32604/ee.2026.080851

Received 16 February 2026; Accepted 06 May 2026; Published online 18 June 2026

Abstract

The dairy processing industries are energy-intensive because of the high level of thermal and refrigeration processes. In this study, a large-scale dairy processing unit in South India has been analyzed thermodynamically and optimized by applying integrated energy and exergy analysis along with heat exchanger network (HEN) optimization. The operational data of one year of a plant manufacturing milk, curd, butter and ghee was analysed. Estimation of theoretical electrical and thermal energy requirements was carried out and compared with the actual plant energy consumption. The exergy analysis was used to identify the thermodynamic irreversibilities and the thermo-economic losses, and pinch analysis was used to identify the potential of maximum heat recovery and to design an optimum HEN configuration. The outcomes reveal that the plant has a mean electrical efficiency of around 41%, a thermal efficiency of 52%, and the overall exergy efficiency is 54%–56%, which shows that the plant has high thermodynamic losses. A pinch analysis was performed, and a pinch temperature of 67°C and significant heat recovery opportunities were identified. Two HEN configurations were compared: one large plate heat exchanger and a two-stage compact system. The optimized two-stage design had an overall heat transfer coefficient that is 48% higher than the single-exchanger design and needed 49% of the heat transfer area. The proposed system can recover 0.68 MW of thermal energy, which translates to an annual reduction in biomass fuel consumption of 2929 t and electrical energy consumption of 1.52 GWh, equating to an estimated annual savings cost of ₹ 3.41 crores (or about 28% of the total energy costs). The proposed thermodynamic optimization framework is a viable and cost-effective method to enhance energy efficiency and sustainability in energy-intensive dairy processing industries.

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Keywords

Energy analysis; exergy analysis; dairy processing industry; heat exchanger network (HEN); pinch analysis; energy efficiency

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