Abstract
This paper addresses evaporation under vacuum condition with the aid from solar energy and the recovered waste heat from the vacuum pump. It is a preliminary attempt to design an innovative solar-based evaporation system under vacuum. The design details, equipment required, theoretical background and work methodology are covered in this article. Theoretically, based on the energy provided by the sun during the day, the production rate of pure water can be around 15kg/m2/day. Assumptions were made for the worst case scenario where only 30% of the latent heat of evaporation is recycled and the ability of the dark droplet to absorb sun energy is around 50%. Both the waste heat from the pump and the heat collected from the photovoltaic (PV) panels are proposed to raise the temperature of the inlet water to the system to its boiling point at the selected reduced pressure.
•Theoretical analysis for desalination under reduced pressure aided by solar energy,•New approach and design for a solar-aided desalination system under reduced pressure,•New approach and design for solar energy collector using spherical-shaped system,•Recycled latent heat of evaporation, waste heat from the vacuum pump, heat collected from the solar panels and droplet colour were considered in the theoretical analysis.