دراسة استقصائية في منظومة تحلية المياه بالطاقة الشمسية باستخدام مواد متغيرة الطور والانابيب الحرارية

An Investigation of a Solar Desalination System with Phase Change Materials and Heat Pipes

Abstract

Solar energy is abundant, renewable and environmentally friendly. It is available in most parts of the world throughout the year. Since solar water desalination systems depend on the intensity of solar radiation, their productivity is low, still additional effective methods are used to heat saline water and store thermal energy. Solar collectors are devices , which used as another source for heating saltwater.Phase change materials are used to ensure that the distillation process continues after sunset.
In the present work, a new five-faceted glass-lid solar still has been designed and implemented. The basin area is (75 × 75) cm, and the height is (10) cm. An external tank (75×75×25) was used to store the phase change materials, and which is connected to the distillation lid through an insulated copper tube. Heat is transferred from the phase change materials to the distillation trough via heat pipes (70 tubes).
(Polyvinylpyrrolidone ,and Polyacrylic Acid) were used as a new phase change material in mixing ratio (30 g per 3 liters of water), and which were mixed with water as a base liquid.
Several practical experiments were conducted on the new system for the period from the end of October to the beginning of November 2020.
The practical results were showed an improvement in the distiller’s productivity with the new shape as it provides a larger space of condensation of steam. It also allows the entry of solar radiation from all directions for the longest possible period during the day. The new distillation system’s daily pure water production (without phase change materials) reached to 4.2 litres per day.
The new phase change materials is contributed to increasing the working hours of the distiller (3-4) hours after sunset. If only (PVP 30 gm per 3 liters of water) was added to the distillation system, daily output increased by 45 percent to obtaine to 6.09 liters/day. While added (25 gm of PVP and 5 gm of PAA per 3 liters of water), the production volume arrived to (7.14 liters per day) with an increase of 70%. The most significant daily yield was achieved during added (20 gm PVP with 10 gm PAA per 3 liters of water), and reached to 7.98 liters per day, with increasing close to 90% increase.
A three-dimensional model was designed through using the SolidWorks 2020 software. While, simulation of the system was carried out using the (Ansys 2021) software.
The numerical and experimental temperature values agreed with a maximum variation range of (4 to 9) oC. The highest percentage error was found as 7.4%. As a result, the thermal behavior of the experimental and numerical studies was close.