LTD Stirling engine with regenerator. Numerical and experimental study

In this paper, a model of a low temperature difference (LTD) Stirling engine with regenerator is presented. The equations governing the heat transfer and the compressible fluid dynamics are solved numerically as a coupled system, including the ideal gas state equation, Navier Stokes equations and energy balance. The engine cycle induces flow compression, expansion and regeneration in free volumes and through porous media. The present developed CFD model makes possible to obtain the instantaneous values of the physical parameters (pressure, temperature, velocity, density, etc.). With these obtained values, the continuous p-V cycle can be analysed which leads to the mechanical work calculation. The results of the simulation concerning an engine with regeneration is compared to those obtained in previous work by an engine without regeneration and validated with experimental data obtained under similar conditions without regeneration. The preliminary results show the important improvement due to the engine regeneration operation and the related regenerator porosity effect allowing the reduction of the pressure drop and viscous dissipation

Dynamic model validation of the radiant floor heating system based on the object oriented approach

International audienceThis paper presents a validated model based on the object-oriented modeling tool based on Modelica approach for the radiant floor heating system, located in thermal laboratory in a test building. The system consists of heat pump, radiant slab, circulation pump, three way valve and hydraulic loop. Single circuit radiant slab was the main component in our Modelica model. A comparison of simulated and measured data for two case studies resulted in maximum absolute error for room temperature, surface temperature, convective heat flow and radiative heat flow as 0.914°C, 0.772°C, 2.5W/m² and4.5W/m² for the first case study and 1.192°C, 1.463°C, 2.275W/m² and 3.9W/m² respectively for the second case study. The simulated results agreed very well with the measured data by taking the measurements errors and the simulation assumptions into account. Therefore, the developed model was validated to be applicable in other projects

Integration of the PCM with intra-ventilation for improved thermal and inertial characteristics of the building envelope

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