Dynamic operating conditions strategy for water hybrid cooling under variable heating demand

• Published in: Applied energy Vol. 237; pp. 635 - 645
• Main Authors: Oliveira, Cíntia Carla Melgaço de, Brittes, José Luiz Pereira, Silveira Junior, Vivaldo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2019
• Subjects: Heat exchanger; Hybrid cooling; Operating conditions correlations; Reduction of electric energy consumption; Variable thermal demand; Operating conditions correlations; Hybrid cooling; Heat exchanger; Reduction of electric energy consumption; Variable thermal demand
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2019.01.053

•Operating conditions of a hybrid cooling system were correlated with their effects.•The operating conditions were set for the maximum water temperature.•Management of the operating conditions decreased the use of total electric power.•Improvements of 35–94% in energy efficiency were obtained in this case study.•Operation under fixed conditions is infeasible in processes with varying demand. This work presents a study of a dynamic strategy for obtaining the lowest consumption of electrical energy in pumps and fans with varying operating conditions for the hybrid cooling of water, which is used as thermal fluid in a cooling unit for vegetable oil. The effects of the operating variables (air flow rate, water flow rate and heating power) on the cooling of water and oil and the electrical energy consumption were evaluated. The selection of the best water-cooling strategy was conditioned to the maximum inlet temperature of 90 °C, resulting in improvements in the energy efficiency that ranged between 35% and 94%, when compared to the use of fixed and nominal operating conditions. Thus, the evaluation of the operating variables effects dependency is strategic for the adequation of the operational conditions and obtainment of better energy efficiency for the process with variable demands.