Effect of charging of phase change material in vertical and horizontal rectangular enclosures in a concentrated solar receiver

Highlights

• Charging of PCM in rectangular enclosures in a concentrated solar receiver is studied.

• The vertical PCM enclosures resulted in enhanced convection heat transfer rate in PCM.

• The horizontal PCM enclosures involves the localized melting of PCM.

Abstract

The charging of phase change material (PCM) in a concentrated solar receiver is experimentally carried out in a parabolic dish collector. Rectangular PCM filled enclosures of 30 mm width in the solar receiver are investigated to study the effect of vertical and horizontal orientations. The selected PCM was a eutectic mixture of KNO₃ and NaNO₃ in 60:40 M ratio with melting point of 210–220 °C. Fin conductive batch heat transfer occurs from the incident surface of the solar receiver to the PCM. The PCM temperatures are measured at five points inside the receiver to observe the temperature distribution and melting conditions. The average temperature of the PCM in the vertical PCM enclosure is observed to be 3.5% more than that of the horizontal PCM enclosures under similar solar radiation and operational duration. Complete melting of the PCM in the vertical container is attained 12.5% earlier than that of the horizontally placed PCM enclosures. The PCM-filled solar receiver possesses the ability to retain the temperature of the receiver, about three times more than the non-PCM receiver due to the constant temperature melting of PCM. Such PCM-filled solar receivers are useful to provide heat for several thermal applications.