A Novel Integrated Direct Absorption Self-Storage Solar Collector

Abstract

The present work introduces a novel integrated solar collector with direct absorption of solar radiation and self-energy storage. The proposed system has compact size without the need for any connecting pipes. The working fluid absorbs the incident solar radiation directly and passes it to the storing fluid container that has been implemented within the core of the novel system. A mathematical model has been presented to describe the thermal behavior of the proposed system. Moreover, an expression has been derived to predict the system efficiency, outlet temperature, and utilized heat transfer. Simultaneously, a comparison of the performance of the novel solar system with that of the conventional solar collector reveals that the performance of the proposed system is much better than that of the conventional collector. The proposed direct absorption collector has a collector efficiency factor, F′ = 1 which is 20% more than that of well-manufactured conventional collectors. This yields about 20% increase in the heat removal factors and efficiency of the integrated system as compared with that of the conventional collectors over the entire range of overall heat loss coefficients and for the same operating conditions regarding working fluid mass flow rate, inlet fluid temperature, ambient temperature, and incident solar radiation. However, it is found that the performance of the integrated collector is more sensitive to the variation in the overall heat loss coefficient and working fluid mass flow rate as compared with the conventional collectors.

Keywords:

• Direct absorption
• Self-storage
• Solar collectors
• Solar energy

ACKNOWLEDGMENT

The authors extend their appreciation to the Deanship of Scientific Research at the King Saud University for funding the work through the research group project (No. RGP-VPP-036).