Ammonium carbamate-based heat exchanger reactor as an endothermic heat sink for thermal management

Johnson, Douglas; Niedbalski, Nicholas; Ervin, Jamie S.; Patnaik, Satwik

doi:10.1016/j.ijheatmasstransfer.2015.07.073

Cited by 10 publications

(9 citation statements)

References 17 publications

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“…14 More importantly, AC can reversibly decompose into NH 3 and CO 2 , as shown in eq 1, and the enthalpy change of the reaction can be up to 159.32 kJ•mol −1 , i.e., 2040.73 kJ•kg −1 . 15 As clear from eq 1, pressure is a strong driving force for the synthesis and the decomposition of AC. 16 The reaction direction can be controlled by regulating the mixed gas pressure, so as to realize heat absorption or release at the specified temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Because of its excellent properties, AC has been tested for a variety of low-grade heat thermal management applications. ,− As an example, Johnson et al , verified that the addition of AC significantly improved, by 58%, the heat transfer of the heat exchange reactor in a novel low-grade heat thermal management system. Koutinas et al proposed a thermochemical solar energy storage system based on the reaction of CO 2 , NH 3 , and AC.…”

Section: Introductionmentioning

confidence: 99%

“…As mentioned before, pressure can indicate and regulate the reaction process of AC. Johnson et al 15,19,20 found that the reaction direction and rate can be controlled by regulating the pressure inside a closed vessel containing the three species. Besides, equilibrium pressure is indispensable in the establishment of the reaction kinetic equation of AC.…”

Section: Introductionmentioning

confidence: 99%

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Solvent Effect on the Chemical Equilibrium of Ammonium Carbamate for Chemical Heat Pump

Dai

Yin

Wang

et al. 2023

Ind. Eng. Chem. Res.

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Chemical heat pump based on ammonium carbamate (AC) is a promising low-grade heat utilization technology. It is essential to know the chemical equilibrium properties in the application of AC-based technologies. AC is usually mixed with solvents to realize circulation. However, the existing studies mainly focus on AC in the solid phase. Therefore, the influence of solvents on the chemical equilibrium of AC was experimentally investigated in this work. The results confirm the solvent effect on the equilibrium pressure of AC in the range of 10∼90 °C. For solvents capable of dissolving AC, the equilibrium pressure increases with both AC concentration and temperature. The solvent effect is mainly due to the influence on both the reaction enthalpy and entropy change terms. An equilibrium pressure–temperature–concentration relationship of AC solution is established. These results provide essential parameters for the design and operation of low-grade heat management and utilization systems based on AC.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Solvent Effect on the Chemical Equilibrium of Ammonium Carbamate for Chemical Heat Pump

Dai

Yin

Wang

et al. 2023

Ind. Eng. Chem. Res.

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“…As an alternative to air, Johnson et al (2015Johnson et al ( , 2017 discussed the use of an expandable material that would absorb the heat generated by the aircraft systems while experiencing an endothermic chemical reaction, before ejecting the collected heat overboard. An example of such materials is ammonium carbamate, a solid ammonium salt that decomposes into carbon dioxide and ammonia gases with an enthalpy of decomposition of approximately 2 MJ/kg.…”

Section: Introductionmentioning

confidence: 99%

Aircraft fuel thermal management system and flight thermal endurance

Manna

Ravikumar

Harrison

et al. 2022

Trans. Can. Soc. Mech. Eng.

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An aircraft thermal management model was created in which fuel is circulated through the heat dissipating components for cooling purposes. A fraction of this fuel is then fed to the engine for combustion, while the excess is cooled by rejecting heat to the ambient and returned to the tank. The thermal management system was designed with the intent of controlling the heat dissipating surface temperature, ensuring a certain heat removal rate, while safeguarding the physical integrity of the fuel. The time variation of the fuel temperature and heat transfer rates was calculated. It was observed that for a constant heat dissipating surface temperature, the heated fuel temperature increased, and the heat removal capacity degraded over time. Conversely, for a specified heat removal rate, both the heat dissipating surface temperature and heated fuel temperature increased during the flight. Lastly, when the maximum fuel temperature was specified, both the heat dissipating surface temperature and heat removal rate decreased over time. In all cases, the time taken for these variables to hit the user-defined threshold values was recorded. A detailed sensitivity analysis was also presented highlighting the critical importance of the fuel recirculation rate on the performance of the thermal management system.

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“…In recent years, expendable heat sinks (EHSs) such as endothermic chemical reactions and liquid gases which can absorb heat at normal/low temperature (below the water freezing point) have attracted more and more attention. Johnson et al [28,29] developed a controllable expendable TMS, which uses the endothermic chemical reaction of ammonium carbamate and propylene glycol as heat sink. Nuzum et al [30,31] presented a cryogenic-based TMS in which the liquefied natural gas (LNG) was used to thermally manage the high energy pulsed systems under low temperature, and the LNG can also be burned in a power plant to generate power for the aircraft energy system.…”

Section: Introductionmentioning

confidence: 99%

Cooling Ability/Capacity and Exergy Penalty Analysis of Each Heat Sink of Modern Supersonic Aircraft

Mao

Wang

et al. 2019

Entropy

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The aerospace-based heat sink is defined as a substance used for dissipating heat generated by onboard heat loads. They are becoming increasingly scarce in the thermal management system (TMS) of advanced aircraft, especially for supersonic aircraft. In the modern aircraft there are many types of heat sinks whose cooling abilities and performance penalties are usually obviously different from each other. Besides, the cooling ability and performance penalty of a single heat sink is even different under different flight conditions—flight altitude, Mach number, etc. In this study, the typical heat sinks which are the fuel mass, ram air, engine fan air, skin heat exchanger, and expendable heat sink will be studied. Their cooling abilities/capacities, and exergy penalties under different flight conditions have been systematically estimated and compared with each other. The exergy penalty presented in this paper refers to the exergy loss of aircraft caused by the extra weight, drag and energy extraction of various heat sinks. The estimation models, as well as the results and discussion have been elaborated in this paper, which can be can be used to further optimize the TMS of modern advanced aircraft, for example, the layout design of various heat sinks and the improvement the control algorithm.

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Ammonium carbamate-based heat exchanger reactor as an endothermic heat sink for thermal management

Cited by 10 publications

References 17 publications

Solvent Effect on the Chemical Equilibrium of Ammonium Carbamate for Chemical Heat Pump

Solvent Effect on the Chemical Equilibrium of Ammonium Carbamate for Chemical Heat Pump

Aircraft fuel thermal management system and flight thermal endurance

Cooling Ability/Capacity and Exergy Penalty Analysis of Each Heat Sink of Modern Supersonic Aircraft

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