Passive, Ejector-Based Cooling System Powered by Low Temperature Heat

M.J. Bergander, D. Butrymowicz, M. Madej
Magnetic Development,Inc. & Marani Sp., United States

Keywords: refrigeration, air-conditioning, renewable energy, injector pumps, waste heat

US military has enormous needs for refrigeration, cooling and air-conditioning, often in tropics, deserts and under extreme weather conditions. Further, operation of airplanes, helicopters, spacecrafts, tanks, transporters requires maintaining temperatures in cabins, electronics and instrumentation within certain ranges. This requires an efficient heat transfer between components. The development presented here explores an intriguing concept - capturing low quality heat (waste, solar, exhaust at temperatures below 100C) to produce cooling. The previous research under other SBIR grants, provided the basics for cooling technology that is powered by low-temperature heat only, without any electricity. It also minimizes the global warming and ozone depletion effects and it uses renewable energies. The innovation uses a new refrigeration cycle that compresses the refrigerant in a liquid state rather than vapor. That compression is accomplished by a two-phase injector pump, a non-mechanical device that does not use any electricity to power. The technology offers an attractive opportunity to develop passive cooling systems with no moving parts, easy to fabricate and practically maintenance-free. Presently, few civilian applications are being investigated - a solar cooling for post-harvest storage of fruits and vegetables and a laptop computer cooling powered by microprocessor heat.