Presentation on theme: "Overview of Heat Activated Heat Pump Development Using the E/C Cycle Richard B. Peterson, Tom Herron, Hailei Wang, and Kevin Drost Department of Mechanical."— Presentation transcript:
Overview of Heat Activated Heat Pump Development Using the E/C Cycle Richard B. Peterson, Tom Herron, Hailei Wang, and Kevin Drost Department of Mechanical Engineering Oregon State University
Motivation and Opportunities Motivation Waste heat, or low-grade heat, is often a “free” resource. Many applications for cooling involve engines with a hot exhaust stream. Burning fuel releases 10x to 100x the energy contained in batteries. Current technology (microchannel heat exchangers and inexpensive expander/compressor machinery) is poised for commercial viability. Opportunities (not an exhaustive list!) Tactical cooling systems for the military use (current funder) Automotive air-conditioning in current and new technology vehicles (hybrids). Also RVs, Trucks, Planes, etc. Chem and bio protection suit cooling for first responders Combined heat, cooling, and power systems for residential service Auxiliary power unit (diesel, micro turbine, etc.) add-ons where cooling is needed
Basic Expander/Compressor Cycle Power Cycle Vapor Compression Cycle Condenser Cooling Components QLQL Q out Power Generating Components QHQH Work Motive Fluid Cooling Fluid
Key Technologies – MECS MECS – Microtechnology-based Energy and Chemical Systems MECS relies on … High rates of heat and mass transfer afforded by microchannels Extremely high degree of control of processes To miniaturize a wide range of systems … Chemical (reactors, mixers, separators, etc.) Energy (heat transfer devices, combustors, etc.) Biological (biosensors, bioreactors, etc.) Enabling portable and distributed systems
How it Works - Heat Exchangers Why? Large surface area Laminar flow Change in relative importance of phenomena and enables systems integration e.g. boiling (surface tension) better thermal management Results in smaller, cheaper, better
Considerations Use Commercially Available Components Where Possible Military Systems Cost is not much of a consideration Reliability, size, and weight are critical Non-portable Commercial Systems Cost is a driver Reliability is important Size and weight not critical Portable (automotive?) Commercial Systems Size, reliability, and cost are critical Weight important, how much is driven by specifics
Summary of Breadboard Work We have demonstrated a prototype expander/compressor operating at 150 W of cooling Mean device efficiency was shown to be 65-70% at 1500 rpm—adequate to reach a COP of 0.7 at design conditions. No regenerator was used in the breadboard system. Follow-on work will include: Investigate the thermodynamic effects of a regenerator in the power cycle. Build and test a 2 kW split cycle heat activated cooler. Build and test a 5 kW combined cycle cooler.
Completed Work – 2 kW System Split Cycle E/C System Separate power and vapor cooling cycles Oil loop used for the power cycle for lubricating the expander Built from both commercial and semi- custom components Status System has been assembled Testing of the individual components and overall system complete Performance data shows expander component requires higher efficiency.
Summary We have demonstrated working systems with promising performance. Key technology remains in the development phase – an expander with the requisite efficiency. No regenerator has been used so far in our efforts. Microchannel component demonstration will be shown on the next generation system.
Next Step – 5 kW System 5 - kW system development is underway with modeling studies and expander development. System will have a single fluid and a common condenser. Microchannel heat transfer components will be included in the overall system. Size, weight, and performance will be key issues to concentrate on.