SUMMARY

The diffusion absorption refrigeration (DAR) cycle is a promising technology for fully thermally driven cooling. It is well suited to applications in medicine refrigeration and air-conditioning in remote settings. However, engineering tools for the technology are limited, so system development has historically been an especially iterative and expensive process. Additionally, conventional system designs require high temperature thermal input for operation, and are unsuitable for low temperature solar- or waste-heat activated applications.

In the proposed effort, component- and system-level DAR engineering tools will be developed. Additionally, a novel configuration will be explored for low source-temperature (110°C) operation. Detailed models for the absorber and bubble-pump generator (BPG) will be developed and validated experimentally. Investigations into the BPG will focus on the Taylor flow pattern in intermediate diameter tubes, which has not yet been thoroughly characterized in the literature, and has numerous industry applications including nuclear fuel processing and well dewatering. A coupling-fluid heated BPG design will also be investigated for low-source temperature operation. Phase-change simulation tools will be developed to model the continuously developing flow in this BPG configuration. These efforts will culminate in the construction and evaluation of a demonstration scale (~25 W cooling) low-source temperature DAR facility.