Heating performance of a solar chimney combined PCM: A numerical case study

Abstract

A c c e p t e d M a n u s c r i p t HIGHLIGHTS  The heating performance of the proposed system was numerically studied. Seven design and operating parameters of the proposed system were investigated. The first five parameters need to be carefully selected to maximize the performance. Thermal conductivity of absorber has less impact on the performance of the system.  Inlet air temperature is also an important factor in this study. ABSTRACTAn experimentally validated numerical model is developed to study the effects of seven design and operational parameters on the heating performance of a solar chimney incorporated with phase change material (PCM) in this paper. It is found that when the latent heat increases from 70 to 170 kJ/kg, the melting time is increased by 103% and freezing time is prolonged by 60%. If heat flux is increased by 33%, the melting time is reduced by 36.4%.Increasing thermal conductivity of the insulation material from 0.02 to 0.06 W/m K, the melting time is prolonged by 47.2 %. When absorptivity of the absorber is increased from 0.8 to 1.0, the melting time is decreased by 26.3 %. When transmissivity of the glass cover is increased by 25 %, the melting time is reduced by 26.7%. For the inlet air temperature, when Page 3 of 44 A c c e p t e d M a n u s c r i p t it decreases from 25 to 15 °C, the freezing time is shortened by 39 %. The melting time is only reduced by 8% when thermal conductivity of the absorber is increased by 25 times.Therefore, it can be concluded that the first six parameters have more impact on the system's performance. While the thermal conductivity of absorber slightly impacts it.Keywords: Solar chimney; Phase change material; Heating performance; Numerical study

A review on the air-PCM-TES application for free cooling and heating in the buildings

“…The results showed that the inclusion of the PCM to a solar chimney reduces the air flow during charging period but increase it during discharging period compared with the solar chimney without PCM [37] However, PCM wallboards also present some disadvantages:…”

“…Passive methods with TES integrated into several building components e.g. wallboards [27][28][29][30][31][32], glass [33], floor [34][35][36] or solar chimney [37] and active methods with the integration of TES in the celling [17][18][19][20], underfloor [21,22] and walls [16,38].…”

Critical review of latent heat storage systems for free cooling in buildings

“…PCMs are usually utilised in solar-PV applications as a passive temperature regulator [164][165][166][167]. PCMs can also be incorporated in solar chimneys replacing the conventional storage material and storing the solar energy gained from the absorber [168,169]. [170], and in (b) a solar chimney [168].…”

“…PCMs can also be incorporated in solar chimneys replacing the conventional storage material and storing the solar energy gained from the absorber [168,169]. [170], and in (b) a solar chimney [168].…”

A review on solar chimney systems

“…In 2014, Liu and Li [181], [182] studied the thermal performance of a solar chimney which was integrated with the phase change material (PCM). They analyzed the PCM behaviors during its melting and solidification processes, absorber surface temperature, mass flow rate, and inlet and outlet air temperature difference.…”