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Experimental thermodynamic analysis of a forced convection solar air heater using absorber plate with pin-fins

  • S. SivakumarEmail author
  • K. Siva
  • M. Mohanraj
Article
  • 25 Downloads

Abstract

This research paper deals with the experimental thermodynamic analysis of a forced convection solar air heater using pin-fin absorber plate and compared with the standard flat absorber plate. The experiments were carried out during the months of February 2018 and March 2018 at Coimbatore city in India. The performance parameters such as, outlet air temperature, energy efficiency, thermohydraulic efficiency, and exergy efficiency are used for performance comparisons. The results showed that the pin-fin absorber plate has about 17 °C higher outlet air temperature when compared to the flat absorber plate. The energy efficiency of a forced convection solar air heater using pin-fin absorber plate was found to be 3% to 12% higher when compared to flat absorber plate with 2% to 11% higher exergy efficiency. The results confirmed that forced convection solar air heaters using pin-fin absorber plate is having significant performance improvement in thermodynamic performance with minimum pressure drop across the air heater duct.

Keywords

Solar air heaters Pin-fins Thermodynamic performance 

List of symbols

A

Area (m2)

cp

Specific heat (J kg−1 K−1)

Dh

Diameter mean diameter (m)

\(\dot{E}x_{\text{des}}\)

Exergy (W)

f

Friction coefficient

hc

Convection heat transfer coefficient (W m−2 K−1)

hr

Radiation heat transfer coefficient (W m−2 K−1)

hfg

Latent heat of paraffin wax (J kg−1 K−1)

h

Specific enthalpy (J kg−1)

I

Intensity of radiation (W m−2)

k

Thermal conductivity (W m−1 K−1)

K

Head loss factor

L1

Length of the solar air heater (m)

L2

Width of the solar air heater (m)

L3

Depth of the solar air heater (m)

\(\dot{m}_{\text{a}}\)

Mass flow rate of air (kg s−1)

p

Pressure (bar)

Pflow

Pumping power (W)

Pblower

Blower power (W)

\(\dot{Q}\)

Amount of heat transfer (W)

\(\dot{Q}_{\text{s}}\)

Energy incident on the solar air heater (W)

R

Gas constant (J kg−1 K−1)

Re

Reynolds number (–)

s

Specific entropy (J kg−1 K−1)

t

Time (s)

T

Temperature (K)

U

Over all heat transfer coefficient (W m−2 K−1)

v

Velocity (m s−1)

x

Thickness (m)

Subscripts

0

Dead state

a

Air

ab

Absorbed

amb

Ambient

ava

Available

b

Bottom

ch

Charging

des

Destruction

e

Edge

f

Fluid

g

Glass

h

Hydraulic

i

Insulation

loss

Heat loss

m

Mean

p

Plate

r, p-g

Radiation heat exchange between plate and glass

r, g-a

Radiation heat exchange between glass and air

s

Stored

t

Top

th-hy

Thermohydraulic

u

Utilised

w

Wind

Greek symbols

\(\psi_{\text{i}}\)

Specific exergy (J kg−1)

τ

Transmissivity

α

Absorptivity

ε

Emissivity

σ

Stefan Boltzmann constant (5.68 × 10−8 W m−2 K−4)

ρ

Density (kg m−3)

η

Efficiency (%)

Δp

Pressure drop (N m−2)

Δptotal

Total pressure drop (N m−2)

Δpch

Pressure drop across the channel (N m−2)

ΔpEntry

Pressure drop at the entry (N m−2)

Δpo

Pressure drop in the orifice meter (N m−2)

Δh

Difference in liquid column (m)

Notes

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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2019

Authors and Affiliations

  1. 1.Department of Automobile EngineeringKumaraguru College of TechnologyCoimbatoreIndia
  2. 2.Department of Mechanical EngineeringHindusthan College of Engineering and TechnologyCoimbatoreIndia

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