دانلود رایگان مقاله بهره وری نوع ساده انرژی خورشیدی با سیستم نانوکامپوزیت ذخیره سازی انرژی

abstract

Paraffin wax (PW) is one of promising solar energy storage materials in solar distillers because of its relatively large latent heat with a stable phase change process. However, paraffin’s low thermal conductivity is a negative aspect for its efficient practice. In this study, adding nanomaterial to enhance paraffin’s low thermal conductivity and its performance parameters is examined. Three cases have been investigated and compared to each others, case 1 without PW, case 2 with PW, and case 3 with copper-PW nanocomposite (NCPW). The results showed apparent advantage of nanocomposite on thermal conductivity of PW and that enhanced the heat energy storage and water productivity. The productivity increased by about 125% and 119% for cases 3 and 2, respectively, compared to case 1. The system working time extended during night by 5 h and 6 h at applying PW and NCPW, respectively. It was also shown that adding nanomaterials to PW can not only increase its thermal conductivity but also the system efficiency and thermal storage capacity

4. Conclusions

This paper experimentally investigates the practice of paraffin wax (PW) as a solar energy storage material integrated with a copper nanocomposite for enhancing its thermal conductivity. Three cases were studied: case 1 without PW, case 2 with PW, and case 3 with Cu-PW nanocomposite (NCPW). Effects of nanocomposite and PW on water productivity and performance of the still’s systems have been examined. Based on the findings, the following conclusions are drawn:
The energy produced during sunshine time is stored efficiently in PW and NCPW for use later during the night; the NCPW is showed more efficient energy storage than the PW.
The water productivity in case 3 is lower than those in cases 1 and 2, at first half of the day; however the overall daily productivity in case 3 is increased by 125% and 106%, compared to cases 1 and 2, respectively.
The daily water productivity in case 2 is higher than that in case 1 by about 19%.
NCPW is recommended as an effective energy storage material in simple-type solar still.
The thermal conductivity of the NCPW was enhanced compared to the PW.
Using nanocomposite can enhance the storage capacity of PW.
The peak temperature of NCPW exceeds that of PW.
The melting process of NCPW is accelerated by 7%, compared to pure PW.
The temperature of saline water in case 1 reaches the maximum limit faster than those in cases 2 and 3 by about 1.5 h.
Case 3 shows the least saline water temperature at first half of the day and the highest value at the rest of the day; case 1 showed the opposed result of case 3, while case 2 comes in between.
The Cu-PW nanocomposite demonstrated enhancement in the thermal properties of PW.
The nanocomposite increased the system efficiency by 5%, compared to pure PW.
Adding nanomaterials to PW can not only increase thermal conductivity and system efficiency, but also thermal storage capacity.
The system working time increased during night by 5 h and 6 h at using PW and NCPW, respectively.