Study of Heat Recovery Equipment for Building Applications

Nowadays, heat exchangers find widespread use across various applications in different fields, particularly in the field of heat recovery. This paper provides a detailed explanation of a plate heat exchanger counter-flow model developed in Simulink/Matlab. Water was employed in simulations for both circuits, although the thermal properties of other fluids can be investigated by modifying them. The "Tanks in series" method was used for simulation purposes. The developed model enables users to explore the impact of various parameters on heat exchanger functionality, such as altering the number of plates, the material or thickness of the plates, and the nature of thermal agents (gaseous or liquid). These models play a crucial role not only in simulating and sizing heat exchangers but also in achieving parametric optimization. Parameter variations can be employed to examine the operation of existing equipment under conditions different from their design specifications. The Simulink/Matlab proposed model, featuring a variable number of finite volumes to ensure high accuracy, was compared to the classical design method for plate heat exchangers. The results revealed good accuracy, with relative errors for heat transfer rate remaining below 2.6%. This research also considered the study of the number of finite volumes necessary for achieving accurate results. For the 40 finite volumes model, the relative error for heat transfer rate is less than 10%. Dividing the mesh into 50 finite volumes along the fluid flow direction resulted in relative errors ranging from 1.6% to 1.7%, indicating that a finer mesh was not necessary. To validate the conceived model, experimental data from the literature were compared. The relative errors for heat transfer rate between the Matlab/Simulink model's results and experimental data ranged from 1.58% to 11.92%, demonstrating a strong agreement between the conceived model and the experimental values.