Existing design of Heat-Pipe Evacuated Tube Collector (HP ETC) for solar water heating require storage tank and additional heat exchanger required for air heating application which leads to the extra spacing and costing requirement. HP ETC have better thermal performance to produce high outlet temperature than flat plate collector (FPC), especially during diffuse solar radiation. But HP ETC normally focusing on water heating system. Furthermore, HP ETC and FPC installation need to be positioned either to south or north facing to ensure the solar thermal collector absorbs more solar radiation. Meanwhile, HP ETC need to be tilt at the correct angle to maximize the performance of the system. These could lead to design limitation. The aim of this research is to develop the new design of Evacuated Glass-Thermal Absorber Tube Collector namely EGATC for drying application. It was developed from conventional HP ETC evacuated glass tube. In this study comparison result of EGATC and HP ETC performance were evaluated. The three days outdoor experiment proves that the performance of EGATC was better than HP ETC in air heating application which is provide higher outlet temperature. Based on the result, EGATC (Day 1: 50.9 oC, Day 2: 53.9 oC, Day 3: 49.2 oC) performed better with slightly higher temperature at outlet temperature compare with HP ETC (Day 1: 46.7 oC, Day 2: 50.3 oC, Day 3: 46.9 oC). It is concluded that EGATC have better performance in term of temperature different and outlet temperature as compared to HP ETC. EGATC (Day 1: 53.6%, Day 2: 50.6%, Day 3: 49.8%) also have greater efficiency in term of heat storage capability as compared to HP ETC (Day 1: 42.7%, Day 2: 41.6%, Day 3: 41.1%). Regarding energy buffer storage, EGATC have better energy storage compared to HP ETC at sudden weather change such as diffuse solar radiation during clouds. The outlet temperature of EGATC (42.3 oC) was remained slightly higher compared to HP ETC (39.9 oC) at the beginning. The outlet temperature gradually drops slower during discharging period until the end of the experiment for 15 minutes towards outlet temperature 41.1ºC and 37.2ºC for both EGATC and HP ETC with temperature difference 1.2ºC and 2.7ºC respectively.

Thermal energy storage (TES) in solar thermal application assist to increase the performance and efficiency of the solar thermal collector system. Various technique has been developed to enhance TES performance such as using water and PCM as energy storage material. Type of material selection and design arrangement also contribute to the performance of solar thermal collector. The aim of this research is to enhance the thermal performance of energy storage on Evacuated Glass-Thermal Absorber Tube Collector (EGATC) for air heating application. The performance study has been conducted to measure the outlet temperature and energy storage rates as per indoor setup under the artificial solar radiation on the effect of parameters such as inner absorber surface area air contact (perforated fins), outer absorber selective coating surface, outer absorber wall thickness, double layer non vacuum glass tube, single layer transparent outer glass tube and single layer thin film inner glass tube. The results showed that the performance of temperature outlet, energy store and energy buffer increase at wind speed 0.9 m/s, zero (0) perforated fin, non-coating outer absorber and 2mm outer absorber wall thickness. It was also demonstrated that a double layer vacuum glass tube showed a better thermal performance enhancement compared with double layer non-vacuum glass tube, single layer transparent outer glass tube and single layer thin film inner glass tube. This concluded that EGATC performance can be increase with those respective parameters.

Several types of flat plate solar collectors have been designed and developed with various technical parameters involved in the design. The inappropriate flat plate solar collector parameter design and material chosen will affect its performance. Investigation on the effect of flat plate absorber collector material, glass thickness, air gap distance, thermal cell absorber thickness, and flat plate absorber base collector thickness on the performance of solar thermal collectors was conducted in this work. The experiment was performed using the solar simulator with solar radiation of 450 and 750 W/m2. The flat plate absorber collector materials used in this experiment were stainless steel 304 and aluminum. The glass thickness used in this experiment was 2.0, 3.0, 4.0, 5.0, and 10.0 mm. The air gap between the flat plate absorber and glass used in this experiment was 0, 5.0, 10.0, 20.0, and 30.0 mm. The stainless steel thermal cell absorber thickness applied in this experiment was 0.5, 1.0, and 2.0 mm. Meanwhile, the aluminum flat plate base absorber base collector thickness was 0.5, 0.8, and 1.0 mm. The results showed that the 2.0 mm glass thickness has the maximum flat plate absorber temperature (88.1 oC at t = 600 s), high heat gain rate (0.097 oC/s), and the highest total heat gain (1207.33 J). The results also revealed that the air gap distance of 10 mm achieved the maximum flat plate absorber temperature (64.6 oC at t = 600 s), the highest heat gain rate (0.058 oC/s), and the highest total heat gain (4750.92 J). The stainless steel thermal cell absorber thickness of 1.0 mm has the thermal cell absorber temperature of 76.2 oC at t = 600 s and a high heat gain rate at 0.08 oC/s. The aluminum flat plate base absorber achieved the highest flat plate absorber temperature (67.2 oC at t = 600 s) and the highest heat gain rate (0.062 oC/s). By using double glass as glass cover increase the flat plate absorber temperature (76.3 oC at t = 600 s) and the highest heat gain rate (0.077 oC/s). This research aims to produce a flat plate absorber with better energy storage, i.e., the performance of the stainless steel plate absorber is better than aluminum with the same thickness. Although the stainless steel flat plate absorber collector showed a lower temperature than aluminum, it has a higher temperature drop than the latter.

Research to improve flat plate solar collector performance such as design and material used continuously developed. This paper's objective is to analyze the performance of the thermal cell absorber attached to a flat plate absorber collector (FPBTCA) through a low thickness design. It will produce a lightweight and portable collector application with efficient temperature conversion duration and has energy storage ability. Stainless steel and aluminum materials with different thicknesses use as thermal cell absorbers then aluminum materials use as a flat plate absorber base-collector. The experiment performs using a solar simulator with solar radiation of 700 W/m2. Referring to the results in term of heat storage (Qstorage), the heat transfer rate of the collector (Q ̇) and efficiency of the collector shows that stainless steel 1.0 mm with an aluminum base absorber (Case E) has a higher value which is 412 kJ, 18.21 kW, and 47.08 %, respectively. The higher total energy gain collected at the bottom plate as dummy load in the drying chamber (T1 and T2) is stainless steel 1.0 mm with an aluminum absorber base-collector (Case E) value of 2.85 kJ. Stainless steel 1.0 mm with an aluminum absorber base-collector (Case E) has the maximum value of energy gain at 300 seconds which is 116.08 J for the bottom plate (T1 and Ta). Flat plate base absorber thermal cell (FPBTCA CASE E) shows better performance in thermal storage than Flat Plate Solar Collector (FPSC).

Thermal energy storage (TES) in solar thermal application assist in increasing the performance and efficiency of the solar thermal collector system. Various technique has been developed to enhance TES performance, such as using water and PCM as energy storage material. The type of material selection and design arrangement also contributes to the performance of solar thermal collector systems. This research aims to enhance the thermal performance of the outlet temperature of an Evacuated Glass-Thermal Absorber Tube Collector (EGATC) for air heating applications. The performance study has been conducted to measure the outlet temperature per indoor setup under the artificial solar radiation on the parameter effect of double pass flow arrangement with pre-heating inner absorber parameter. The comparison experiment at wind speed 0.9 m/s for stainless steel inner absorber showed better results on temperature outlet 47.7°C, energy store 4.46KJ and efficiency (collector + storage) 37.5% compared with insulation materials internal absorber with temperature outlet 44.7°C, energy store 4.40KJ and efficiency (collector + storage) 31.1%, respectively. This concluded that EGATC performance can be increased with those respective parameters.