Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : PCM

Thermal Storage Efficiency Enhancement for Solar Air Heater Using a Combined SHSm and PCM Cylindrical Capsules System: Experimental Investigation

Akram H. Abed

Engineering and Technology Journal, 2016, Volume 34, Issue 5, Pages 999-1011

Thepresent work aims to enhance the thermal storage efficiency and thermal behavior for solar air heater integrated with cylindrical capsulessystem. The cylindrical capsule has diameter 50 mm and length 600 mm, placed in the crossflow of airstream.In this experimental study, a high specific heat of latent heat storage materials (PCM-paraffin wax) wereinvestedto increase the stored ability for sensible heat storage materials (pure sand). Three cases are testedunderconstant incident irradiation 1000Wm-2, in the first case cylindrical capsules packed with pure sand, second case cylindrical capsules packed with compound (sand+10% PCM) and third case cylindrical capsules packed with compound (sand+20% PCM), for both natural convection and forced convection with different mass flow rates (0.5 , 1.132 kg/min). The experimental results indicated that the compound (sand+20%PCM) gives the best thermal storage duration (380 min),with increase in outlet air temperature by approximately 5.6 % in forced convection with (0.5 kg/min) compared with pure sand (240 min). For forced convection with (1.132 kg/min), compound (sand+20%PCM) gives (355 min) thermal storage duration with increase in outlet air temperature by approximately 9.2 % compared with pure sand (220 min).Increase of mass flow rate leads to decrease the outlet air temperature period time of the discharge process.

Numerical Investigation of Energy Storage in Packed Bed of Cylindrical Capsules of PCM

Ahmed K. Alshara; Mohammed Kh. Kadhim

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 494-510

A theoretical study of storage thermal energy using capsulated cylinders filled with phase change material PCM is performed. These cylinders are arranged in-line in the direction of heat transfer fluid. The energy equations of fluid (water) and PCM capsules are solved numerically using finite volume method with heat capacity method for phase change of PCM. The effect of Reynolds number and the ratio of pitch to diameter of the cylinders on the temperature distribution and melt fraction are presented. The results show that the increment of both Reynolds number and the ratio of the pitch to diameter gives decrement in the final time of melting of PCM in the cylinders.