Experimental and Computational Investigation of Heat Transfer in an Open Volumetric Air Receiver for Process Heat Applic
India receives abundant solar irradiance with an annual average of ~19.97 MJ/m2 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 significa
- PDF / 400,911 Bytes
- 12 Pages / 439.37 x 666.142 pts Page_size
- 3 Downloads / 256 Views
Abstract India receives abundant solar irradiance with an annual average of *19.97 MJ/m2 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 °C. Considering these aspects, as a research initiative, open volumetric air receiver (OVAR) is being developed with a peak-power capacity of 4 kWth. 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 (Ɛ) *52% at POA/MFR ¼ 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 Ɛ * 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 Ɛ * 42, 52, and 62%; (e) Predictions with incident radiation onto the front surface of porous absorber.
P.S. Ghoshdastidar Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India L. Chandra (&) Department of Mechanical Engineering and Center for Solar Energy, Indian Institute of Technology Jodhpur, Jodhpur 342011, Rajasthan, India e-mail: [email protected] P. Sharma R. Shekhar Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India © Springer Nature Singapore Pte Ltd. 2018 L. Chandra and A. Dixit (eds.), Concentrated Solar Thermal Energy Technologies, Springer Proceedings in Energy, https://doi.org/10.1007/978-981-10-4576-9_10
103
104
P. Sharma et al.
Keywords Solar energy Open volumetric air receiver (OVAR) CFD POA/MFR Local thermal nonequilibrium model (LTNE)
Absorber
Nomenclature qf vðv1 ; v2 ; v3 Þ Ef gth Shs Tf t µ kf RANS hfs Ts Ɛ p y+ Shf Afs
Density of fluid (kg/m3) Velocity vector Total fluid energy (J) Thermal efficiency Solid enthalpy source term Temperature of fluid (K) Time (s) Viscosity of air (kg/m s) Thermal conductivity of fluid (W/mK) Reynolds Average Navier–Stokes Heat transfer coefficient for the fluid/solid interface Temperature of solid (K) Porosity (%) Static pressure (Pa) Nondimensional wall distance Fluid enthalpy source term Interfacial area density, i.e., the ratio of the area of the fluid/solid interface and the volume of the porous zone
1 Introduction Growing energy demands and environmental impact of fossil fuels needs to look for the alternative fuel sources mainly from the renewable sources [1]. Solar energy is acknowledged as a prominent alternative. To harness solar energy, in an efficient manne
Data Loading...
