# Thermal Characteristics and Parametric Analysis of an Improved Solar Wall
## 1 Introduction
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**Author** & **Types** & **Diagram** & **Inference** \\ \hline [PERSON]. [PERSON] et al. [5] & solar air heater duct having multi V-shaped ribs on the absorber plate & & The maximum value of the thermal performance parameter was 1.93 for the range of parameters investigated. \\ [PERSON] et al. [6] & impingement on corrugated absorber plate & & The thermal efficiency of proposed design duct is observed almost 14\% more as compared to the smooth duct. \\ [PERSON], [PERSON] [7] & flat plate solar air heaters-double pass flat and v-corrugated plate & The annual average of a nickel–tin selectively coated absorber is higher than that with a black painted absorber by 29.23\%. \\ [PERSON] et al. [8] & double pass solar air collector with and without porous material & Thermal efficiency of double pass solar air collector with porous absorbing material is 20–25\% higher than that of collector without porous absorbing material. \\ [PERSON] et al. [9] & a double pass solar air heater with with fins attached and using a steel wire mesh as absorber plate & The efficiency of the double pass is found to be higher than the single pass by 7–19.4\%. \\ [PERSON] et al. [10] & a solar air heater with packed-bed latent storage energy & The daily energy efficiency varied between 32\% and 45\%. While the daily exergy efficiency varied between 13\% and 25\%. \\ [PERSON] et al. [11] & double glazing flat-plate solar air collectors & The efficiency factor and total heat loss coefficient of Model 4 are 0.62707 and 2.21745, respectively. \\ \hline \end{tabular}
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Table 1: Investigations on thermal performance of different types of solar air collectors. advantages of solar air heaters, a range of numerical simulations has been performed for thermal performance optimization [29; 30; 31]. A mathematical model based on a numerical finite-difference approach was proposed for a flat-plate solar air collector in reference [32]. [PERSON] et al. [33] presented a mathematical model to determine the optimum reflector position of a double-exposure flat-plate solar collector using FORTRAN language. Based on the two-node lumped heat capacitance method, dynamic thermal performance prediction models for flat-plate solar collectors were proposed and validated using dynamic tests [34]. The thermal behavior of double parallel flow air heating collectors working by natural convection was also studied. A GTC (glazed transpired solar collector) with perforating corrugated plate was developed by [PERSON] et al. [35], and the simulated results showed that its thermal performance and economic characteristics were better than other transpired solar collectors. Due to the above studies, buildings integrated with passive solar heating systems are widely used because of the high heat efficiency of solar air collectors [36; 37; 38; 39; 40; 41; 42]. Pertinent literature reveals that a good number of investigations are carried out in the recent past. However, some problems also have not been solved during the application of solar air collectors, such as overheating during summer and inconvenient operation control by manual dampers. A concept of \"passive heating and cooling by color-changing\" was put forward in our previous research [43; 44], and an experimental study of thermal responsive of the color-changing solar wall was carried out. However, there are still some problems, such as inconvenient manual control operation and low thermal efficiency. Therefore, the aim of this work is to propose the automatic control component and optimize the heat collection efficiency. To achieve this goal, the design and construction of this solar wall are detailed, photo-electric fan and temperature-controlled damper are proposed and thermal characteristics of these automatic control components are evaluated by measuring hygothermal parameters. Meanwhile, parametric analysis was performed based on the mathematical model and the optimization results of thermal performance simulation are presented.