Overview of Heat Activated Heat Pump Development Using the E/C CycleMotivation and OpportunitiesBasic Expander/Compressor CycleKey Technologies – MECSHow it Works - Heat ExchangersConsiderationsCompleted Work – Breadboard SetupSummary of Breadboard WorkSlide 9SummaryNext Step – 5 kW SystemOverview of Heat Activated Heat Pump Development Using the E/C CycleRichard B. Peterson, Tom Herron, Hailei Wang, and Kevin DrostDepartment of Mechanical EngineeringOregon State UniversityMotivation 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 neededBasic Expander/Compressor CyclePower CycleVapor Compression CycleCondenserCoolingComponentsQLQoutPowerGeneratingComponentsQHWorkMotiveFluidCoolingFluidFluidFluidKey Technologies – MECSMECS – 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 systemsHow it Works - Heat ExchangersWhy?•Large surface area•Laminar flow • Change in relative importance of phenomenaand enables systems integration  e.g. boiling (surface tension) better thermal management•••Results in smaller, cheaper, betterConsiderations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 specificsCompleted Work – Breadboard SetupEvaporatorFlow MetersVaporizerPumpDynoExpander/ CompressorSummary 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