*8.1.2 Flat plate non: integrated solar collector*

In Flat plate non – integrated solar collectors connected to PCM storage unit. The PCM storage unit is placed on upper of an inclined collector, near the solar collector or under the solar collector. To avoid the leakage, the PCMs are encapsulated in rectangular, cylindrical, and spherical container (**Figure 12; Table 3**).

**Figure 11.** *PCM in flat integrated solar collector.*

**Figure 12.** *PCM in in flat non-integrated solar collector.*

*Phase Change Materials for Renewable Energy Storage Applications DOI: http://dx.doi.org/10.5772/intechopen.98914*


#### **Table 3.**

*Merits and demerits of regular PCM container for different medium [54].*

Incorporating solar energy storage system into building may diminish cost of renewable energy storage system and also progress efficiency of the collection. In solar water heating process, the storage unit is filled with PCM for captivating the heat during day from hot water. At night, the absorbed energy supplies to the warm water tank and hot water can be collected for a long time [55, 56]. Kulakarni and Deshmukh [57] studied efficiency of water heating system using paraffin whose melting point was 62°C. Efficiency of solar water heater increased from 31.25% to 44.63%. The storage capacity was enhanced from 3260.4 kJ to 4656.5 kJ. Bhargava [58] utilized three different thermal properties of PCMs such as Na2SO4. 10H2O (32 °C and 251 kJ/kg), Na2HPO4.12H20 (36.1°C and 279 kJ/kg) and P116 (46.7°C and 209 kJ/kg) Wax were incorporated into storage unit. Determined the efficiency of the system and duration of the outlet water temperature. As thermal conductivity of the materials are increased, Increased duration of outlet hot water temperature during the evening hours. Fazilati and Alemrajabi [59] used Paraffin as storage medium. The melting point and latent heat of fusion were 55°C and 187 kJ/kg. 39%, 16% and 25% improved the energy and exergy efficiency and duration of warm water was improved. Prakash et al. [60] laminated a PCM layer (46.7°C and 209 kJ/kg) at the bottom of the water tank. They concluded that, it was not effective during phase change from liquid to solid due to low heat transfer area. Kaygusuz [61] had studied performance of solar water with CaCl2.6H2O (28°C and 45 kcal/kg) as phase change material an experimental and theoretically. Hasan et al. [13–15] incorporated some fatty acids as PCMs such as myristic acid (MA), palmitic acid (PA) and stearic acid (SA) for domestic water heating. They recommended that these fatty acids with melting temperature between 50–70°C were the most auspicious PCMs for water heating. Most of the researchers were studied with different phase transition temperature in solar water heater system. However, as per the Cabinet of Ministers of Latvia, the allowable domestic hot water (DHW) range must be from 55 to 70°C [62]. Literature review given in **Table 4** on phase transition temperature rage in 55 to 70 °C for DHW.

Other than above PCM, some of commercial available within 55–70°C of thermal storage materials are listed out in Zalba et al. [78]. These materials may have applied in Flat Plate Solar water heater for better thermal efficiency, thermal management and longer duration for warm water.

#### *Management and Applications of Energy Storage Devices*


**Table 4.**

*Literature review on PCM flat plate solar collector for water heater.*
