Enhancement of heat transfer in a plate heat recuperator using turbulence-generating plates

Maintaining air quality and a comfortable indoor microclimate is ensured by HVAC systems, however, their operation is associated with substantial energy consumption, particularly during the cold season, when heating the supply air may double the total heating costs. One of the most promising technologies for significantly improving building operation efficiency and reducing energy expenditures required to maintain comfortable climatic conditions is the use of ventilation systems with heat recuperation, which enable the return of thermal energy from exhaust air back into the premises through heat exchangers. The objective of the present study is to enhance the efficiency of heat transfer in a ventilation system with heat recuperation by means of structural modernization through the integration of additional plates that intensify the turbulent flow regime of the heat-transfer medium. To achieve this objective, an accurate computational model was developed, based on the numerical solution of the Reynolds equations of motion and the application of the standard k-ε turbulence model. The study revealed that the efficiency of heat recuperation can be increased by adding additional plates to the system that induce turbulence in the airflow. The optimization of the recuperator’s design was carried out using the coordinate descent method. Patterns of variation in the following parameters were identified: separation line configuration, pressure loss, heat transfer coefficient, and Reynolds number depending on the geometric dimensions of the plates. The optimal dimensionless ratios are: l/d = 7, h/d = 0.6, δ /d = 0.1. Expressions have been obtained for calculating the heat transfer coefficient and pressure loss when using plates in the recuperator. The results obtained are of practical value for the design of supply and exhaust ventilation systems with heat recuperation