CFD Simulation of A Novel Energy Saving System for Domestic Heating and Ventilation

Abstract

A numerical investigation has been conducted by CFD technique to examine the performance of a novel energy saving device (Thermocill) for domestic heating. The mesh generation and the simulations were performed in STAR ccm+. In addition, a Steady-State RANS approach was used in this project. The standard k-ε model and SST k-ω model were utilised and the main focus was on SST k-ω. The case study in this project was a 2D room and all the walls (including the window) have their real boundary conditions regarding to the heat gain and dissipation. The main heat transfer mode in this project is the natural convection that rises from the heat source. Several cases have been studied to examine the design’s effect on the performance of Thermocill. The results of the simulations in this project have been highly affected by the convergence issue duo to the complexity of simulating the natural convection. It was observed that the nature of the problem is transient, and it could be difficult to obtain a steady-state solution. In the case 1 (without applying Thermocill), the thermal stratification in the room was observed as the density gradients effect the velocity magnitude to be varied in different locations in which the circulation of the air was observed duo to the heated and cold surfaces. No significant difference between the cases with and without Thermocill was evident. However, observations were made only on the device, and it was found that the mass flowrate of the modified design of Thermocill with channel’s height of 17 mm increased by 124.9 % in comparison to case 3 whose channel’s height 14 mm. Limitations of the current study and future recommendations have been stated which include running 3D simulation as transient to obtain better observations on the problem.