New aqueous solution for direct solar absorption refrigeration systems

Solar-driven absorption refrigeration technology has the potential to reduce the peak electricity demand and global warming. Optimization of this technology can change the future energy economy of the world. Herein, the straightforward and inexpensive preparation of new stable aqueous solution for direct solar absorption refrigeration systems is reported. Standard copper solution can be added to the aqueous lithium bromide solution used in absorption refrigeration systems in a simple one-step process under ambient conditions. The resulting solution is multifunctional as it improves the steam absorption in the absorber, absorbs the solar energy and converts it directly to heat, enhancing the efficiency of steam generation in the generator. Experiments to measure the viscosity, thermal conductivity, transmittance, photo-thermal conversion and steam absorption are demonstrated. The results show an enhancement of ~32.5% in the direct photo-thermal conversion and ~10.5% in the steam absorption rate, and negligible change in the viscosity and thermal conductivity of the new aqueous solution comparing to the conventional one. Thus, this stable new solution might be considered as an alternative of nano solutions and it has the potential to improve the solar absorption refrigeration technology, reducing the size and cost and saving Earth.