A MONOLITHIC, MODULAR, PASSIVELY DRIVEN EJECTOR-BASED HEAT PUMP

Ejector-based heat pumps are well-suited for cooling, heat pumping, and water-harvesting applications, especially for off-grid or mobile applications, because of the absence of a compressor and the use of a single-constituent, non-toxic working fluid with low global warming potential. Taking advantage of the mechanical simplicity of ejectors and injectors, this work presents a concept for a monolithic heat driven heat pump that includes all components of a passively driven ejector-based system (heat exchangers, ejector, and injector) in one compact, modular unit. This technology has the potential to transition ejectorbased heat pump concepts from thermodynamically attractive systems into functional, manufacturable, and marketable technology that will benefit the environment through the use of safe working fluids and reduced primary energy consumption. The basic modeling techniques for cycle and component (ejector, injector, and heat exchanger) design, and the incorporation of the ejector and injector designs into a monolithic assembly, are demonstrated. Based on cycle- and component-level modeling, it is found that a theoretical cooling mode Coefficient of Performance (COP) of 0.2 can be attained using R245fa with waste heat at a source temperature of ~120°C.