Feasibility study of power generation through waste heat recovery of wood burning stove using the ORC technology

Abstract

Waste heat recovery of low-to-medium grade heat sources such as solar energy or biomass using Organic Rankine Cycle (ORC) technology has received growing attention recently. Few manufacturer of biomass (wood logs) stoves utilizes silicon-carbide as the material for manufacturing of their stoves to facilitate slow-heat-release for a long period of time for up to twelve hours. Despite good performance of these stoves, there is still significant amount of heat that is wasted through exhaust at the temperature of between 240°C to 270°C. This paper investigated various strategies to minimize heat losses to the environment by introducing an ORC system that can capture the waste heat and convert it into useful power. The stove’s temperature distribution as well as identification of potential location for the ORC evaporator were obtained using experimental testing. Such results were then employed for validation of a CFD model and it was shown that this CFD model can fairly accurately predict both temperature distribution and recovered heat on the ORC evaporator coils. Among investigated scenarios, “Modification 2” proved to be most effective as it not only preserved the heating functionality of the stove but also improved the stove’s efficiency by about 20% while generating 1.113kW of electricity.