Toe Cozy
New member
- Joined
- Sep 1, 2004
- Messages
- 497
- Reaction score
- 102
Here's the second one Chip sent me. Again, I know there's a lot of engineer types out there. Get crackin'! Hope this entertains a few of you problem solvers:
A06-174 TITLE: High-Efficiency Heat Exchanger for Individual Stoves
TECHNOLOGY AREAS: Human Systems
ACQUISITION PROGRAM: PEO Combat Support & Combat Service Support
OBJECTIVE: Develop heat-exchanger technology that will increase heat-transfer efficiency in personal stoves for heating water and melting snow.
DESCRIPTION: Individual stoves have been identified as an essential multipurpose item for heating water and rations, and for personnel hygiene. During cold weather operations, a personal stove can be necessary for survival. Commercial stove technology has advanced in recent years, producing models that are smaller, lighter, and easier
to operate and maintain. A new JP-8 fuel stove based on Capillary Force Vaporizer (CFV) technology (see reference #1) sets new standards for size, weight, and ease of use. However, the heat-transfer efficiency has not improved, remaining about 30% efficient for typical use. Furthermore, slight cross winds can significantly decrease performance, as do small or odd cup shapes like the kidney-shaped canteen cup. Efficiency is tantamount to stove and fuel weight and time to heat water and rations to an acceptable temperature. Some stoves contain as much fuel as the dry weight of the
stove itself. Doubling or tripling the efficiency provides weight savings, and the time required to heat water or melt snow is significantly reduced.
Since heat-transfer efficiency is largely a geometric function of the object being heated, a new technology is being sought for integration with a cup or pot, henceforth referred to as the Heat Exchanger Cup (HEXC), which improves the heating performance of stoves. Potential technologies include lightweight conductive materials and coatings, insulations and covers, high surface-area finned heat exchangers, microchannel heat exchangers, and catalysts that promote complete combustion. Catalysts may
also reduce carbon monoxide, a combustion byproduct that is deadly when using stoves in confined spaces.
The HEXC shall hold at least 1/2 liter of water and fit snugly around the bottom of a standard 1 liter Nalgene brand polycarbonate bottle for compact transport. The HEXC shall be designed to work with the new CFV JP-8 fired stove, which has an output of 1.1-1.4 kW, and it should also be compatible with the Squad Stove (Optimus Nova and MSR Dragonfly, see reference #2).The HEXC shall weigh no more than 225 grams (150 grams desired). Minimum desired efficiency is 60% (75% desired), as determined by
heating 454 grams of water from 4°C to 60°C in a cross wind of 8 km/h and dividing the energy added to the water (~106 kJ) by the heating value of JP8 fuel consumed. The
HEXC shall be safe to handle when hot by means of a cozy, insulation, wire handles, or similar; any exposed parts should cool quickly to minimize the potential for severe burns. The HEXC design shall not cause accumulation of soot or unburned hydrocarbons on exposed exterior surfaces. The water-contact surfaces shall allow proper cleaning and sanitation. The HEXC shall be robust enough for field use, not easily crushable by hand and capable of surviving an accidental one-meter drop when stored around the water bottle. The target production cost is less than $50.
PHASE I: Develop a proof-of-principle demonstrator capable of the performance mentioned above. To establish validity, materially demonstrate, through testing, the feasibility and practicality of the proposed design, including mitigation of risks associated with factors limiting system performance. A final report shall be delivered that specifies how requirements will be met. The report will detail the conceptual design, performance modeling, safety and MANPRINT, and estimated production costs.
PHASE II: Refine the technology developed during Phase I in accordance with the goals of the project. Fabricate and demonstrate an advanced prototype, verifying that the desired performance is met. Deliver a report documenting the theory, design, component specifications, performance characterization, and recommendations for technique/system performance. Provide prototype units suitable for display and Army field testing.
PHASE III: The outdoor recreational market for camp stoves is much larger than the military market. Any advances in system weight and efficiency can easily be marketed to outdoor enthusiasts, particularly campers, hikers, and mountain climbers. Stoves are also purchased for emergency use.
REFERENCES:
1) Modular Individual Water Heater fact sheet,
http://nsc.natick.army.mil/media/fact/food/miwh.pdf
2) Squad Stove fact sheet,
http://nsc.natick.army.mil/media/fact/food/squad_stove.pdf
3) Detail Specification MIL-DTL-83133E - Turbine Fuels, Aviation, Kerosene Types,
NATO F-34 (JP-8), NATO F-35, and JP-8+100 (consult SITIS under this topic number for
further information).
KEYWORDS: stove, campstove, combustion, heating, heat exchanger
TPOC: Leigh Knowlton
Phone: (508) 233-5183
Fax: (508) 233-5556
Email: [email protected]
A06-174 TITLE: High-Efficiency Heat Exchanger for Individual Stoves
TECHNOLOGY AREAS: Human Systems
ACQUISITION PROGRAM: PEO Combat Support & Combat Service Support
OBJECTIVE: Develop heat-exchanger technology that will increase heat-transfer efficiency in personal stoves for heating water and melting snow.
DESCRIPTION: Individual stoves have been identified as an essential multipurpose item for heating water and rations, and for personnel hygiene. During cold weather operations, a personal stove can be necessary for survival. Commercial stove technology has advanced in recent years, producing models that are smaller, lighter, and easier
to operate and maintain. A new JP-8 fuel stove based on Capillary Force Vaporizer (CFV) technology (see reference #1) sets new standards for size, weight, and ease of use. However, the heat-transfer efficiency has not improved, remaining about 30% efficient for typical use. Furthermore, slight cross winds can significantly decrease performance, as do small or odd cup shapes like the kidney-shaped canteen cup. Efficiency is tantamount to stove and fuel weight and time to heat water and rations to an acceptable temperature. Some stoves contain as much fuel as the dry weight of the
stove itself. Doubling or tripling the efficiency provides weight savings, and the time required to heat water or melt snow is significantly reduced.
Since heat-transfer efficiency is largely a geometric function of the object being heated, a new technology is being sought for integration with a cup or pot, henceforth referred to as the Heat Exchanger Cup (HEXC), which improves the heating performance of stoves. Potential technologies include lightweight conductive materials and coatings, insulations and covers, high surface-area finned heat exchangers, microchannel heat exchangers, and catalysts that promote complete combustion. Catalysts may
also reduce carbon monoxide, a combustion byproduct that is deadly when using stoves in confined spaces.
The HEXC shall hold at least 1/2 liter of water and fit snugly around the bottom of a standard 1 liter Nalgene brand polycarbonate bottle for compact transport. The HEXC shall be designed to work with the new CFV JP-8 fired stove, which has an output of 1.1-1.4 kW, and it should also be compatible with the Squad Stove (Optimus Nova and MSR Dragonfly, see reference #2).The HEXC shall weigh no more than 225 grams (150 grams desired). Minimum desired efficiency is 60% (75% desired), as determined by
heating 454 grams of water from 4°C to 60°C in a cross wind of 8 km/h and dividing the energy added to the water (~106 kJ) by the heating value of JP8 fuel consumed. The
HEXC shall be safe to handle when hot by means of a cozy, insulation, wire handles, or similar; any exposed parts should cool quickly to minimize the potential for severe burns. The HEXC design shall not cause accumulation of soot or unburned hydrocarbons on exposed exterior surfaces. The water-contact surfaces shall allow proper cleaning and sanitation. The HEXC shall be robust enough for field use, not easily crushable by hand and capable of surviving an accidental one-meter drop when stored around the water bottle. The target production cost is less than $50.
PHASE I: Develop a proof-of-principle demonstrator capable of the performance mentioned above. To establish validity, materially demonstrate, through testing, the feasibility and practicality of the proposed design, including mitigation of risks associated with factors limiting system performance. A final report shall be delivered that specifies how requirements will be met. The report will detail the conceptual design, performance modeling, safety and MANPRINT, and estimated production costs.
PHASE II: Refine the technology developed during Phase I in accordance with the goals of the project. Fabricate and demonstrate an advanced prototype, verifying that the desired performance is met. Deliver a report documenting the theory, design, component specifications, performance characterization, and recommendations for technique/system performance. Provide prototype units suitable for display and Army field testing.
PHASE III: The outdoor recreational market for camp stoves is much larger than the military market. Any advances in system weight and efficiency can easily be marketed to outdoor enthusiasts, particularly campers, hikers, and mountain climbers. Stoves are also purchased for emergency use.
REFERENCES:
1) Modular Individual Water Heater fact sheet,
http://nsc.natick.army.mil/media/fact/food/miwh.pdf
2) Squad Stove fact sheet,
http://nsc.natick.army.mil/media/fact/food/squad_stove.pdf
3) Detail Specification MIL-DTL-83133E - Turbine Fuels, Aviation, Kerosene Types,
NATO F-34 (JP-8), NATO F-35, and JP-8+100 (consult SITIS under this topic number for
further information).
KEYWORDS: stove, campstove, combustion, heating, heat exchanger
TPOC: Leigh Knowlton
Phone: (508) 233-5183
Fax: (508) 233-5556
Email: [email protected]
