Experimental and Computational Investigation of Heat Transfer in an Open Volumetric Air Receiver for Process Heat Application

India receives abundant solar irradiance with an annual average of similar to 19.97 MJ/m(2) per day in Jodhpur only. This solar energy can be harnessed for electricity generation, melting or heat treatment of metals. Use of air as heat transfer fluid offers significant advantages of being nontoxic, freely available and operating temperature beyond 800 degrees C. Considering these aspects, as a research initiative, open volumetric air receiver (OVAR) is being developed with a peak-power capacity of 4 kW(th). The installed testing facility at IIT Jodhpur includes sub systems, which are thermal energy storage (TES), air-water heat exchanger. In the absence of solar simulator electrical heating is being employed for circumferential (external) heating of the absorbers. In particular, the presented paper presents: (a) Effect of pore diameters (2 and 3 mm) on the average outlet temperature of absorber with porosity (epsilon) similar to 52% at POA/MFR = 100 kJ/kgK, where POA is the equivalent Power-On-Aperture and MFR is mass-flow rate of air; (b) Efficiency performance curve for absorbers with epsilon similar to 52%; (c) Modeling of heat transfer in absorber with adopted commercial CFD tool FLUENT including returned air circulation; (d) Comparison between CFD analyzed and experimentally obtained temperature for absorbers with epsilon similar to 42, 52, and 62%; (e) Predictions with incident radiation onto the front surface of porous absorber.