Simulation the effectiveness of heat recovery of the regenerative ventilator using different approaches

Abstract

Today buildings should be designed for energy efficiency class not less than C. This requires ventilation with heat recovery. On the market, there are different compact heat recovery ventilation units for decentralized ventilation. Regenerative ventilators represent a promising area of effective ventilation with exhaust air heat recovery. They operate cyclically for the inlet and outlet of air. These kinds of ventilators should work in a blocked pair(s) – one for input and one for output in each pair. If not, the effectiveness will decrease. A mathematical model of the ceramic heat regenerator in the regenerative ventilator “Twin Fresh” by Vents has been created to improve the efficiency of its operation. In previous works, on the basis of two different approaches, the operation of the heat regenerator was simulated. The first one uses M. Mikheev’s formula for the Nusselt number. The second one is computational fluid dynamic simulation by SolidWorks Flow Simulation. The efficiency coefficients obtained as a result of the simulation had a significant difference – up to 66.5 %. The aim of the work is to find alternative methods for adequately determining the efficiency of the ventilator. A mathematical simulation was performed using a different formula from “Novyi spravochnik khimika i tekhnologa. Protsessy i aparaty khimicheskikh tekhnologii”. This formula takes into account the Grashof number. Values obtained are significantly different from both previous ones – up to two times. There is no information in the literature about the experimental conditions for determining the Nusselt number, which was used in the simulation. Therefore, we can’t assume, what approach is closer to the conditions of the ceramic regenerator. There is a need to conduct experimental studies to determine the efficiency of the regenerative heat exchanger.