Full-scale multi-ejector module for a carbon dioxide supermarket refrigeration system: Numerical study of performance evaluation

2017 ◽  
Vol 138 ◽  
pp. 312-326 ◽  
Author(s):  
Jakub Bodys ◽  
Michal Palacz ◽  
Michal Haida ◽  
Jacek Smolka ◽  
Andrzej J. Nowak ◽  
...  
2013 ◽  
Vol 281 ◽  
pp. 324-328 ◽  
Author(s):  
Dileep Kumar Gupta ◽  
Mani Shankar Dasgupta

Carbon dioxide is one of the rediscovered sustainable options, as CFCs and HFCs are now in the list of regulated substances, to be phased out in time bound way. There are however various challenges to the successful use of CO2 as refrigerant. Cost effective and widely acceptable technology is demand of the time. Performance of trans-critical CO2 refrigeration systems is found to be sensitive to the gas cooler design. In the present work a detailed mathematical model is developed for a finned tube air cooled gas cooler and the same is validated using published literature. Subsequently, to achieve the lowest possible approach temperature, the performance of the gas cooler is analyzed for various air velocity and alternate pipe arrangements. The effect of increase in size of gas cooler to its performance is also studied.


Author(s):  
Brian Hollon ◽  
Erlendur Steinthorsson ◽  
Adel Mansour ◽  
Vincent McDonell ◽  
Howard Lee

This paper discusses the development and testing of a full-scale micro-mixing lean-premix injector for hydrogen and syngas fuels that demonstrated ultra-low emissions and stable operation without flashback for high-hydrogen fuels at representative full-scale operating conditions. The injector was fabricated using Macrolamination technology, which is a process by which injectors are manufactured from bonded layers. The injector utilizes sixteen micro-mixing cups for effective and rapid mixing of fuel and air in a compact package. The full scale injector is rated at 1.3 MWth when operating on natural gas at 12.4 bar (180 psi) combustor pressure. The injector operated without flash back on fuel mixtures ranging from 100% natural gas to 100% hydrogen and emissions were shown to be insensitive to operating pressure. Ultra-low NOx emissions of 3 ppm were achieved at a flame temperature of 1750 K (2690 °F) using a fuel mixture containing 50% hydrogen and 50% natural gas by volume with 40% nitrogen dilution added to the fuel stream. NOx emissions of 1.5 ppm were demonstrated at a flame temperature over 1680 K (2564 °F) using the same fuel mixture with only 10% nitrogen dilution, and NOx emissions of 3.5 ppm were demonstrated at a flame temperature of 1730 K (2650 °F) with only 10% carbon dioxide dilution. Finally, using 100% hydrogen with 30% carbon dioxide dilution, 3.6 ppm NOx emissions were demonstrated at a flame temperature over 1600 K (2420 °F). Superior operability was achieved with the injector operating at temperatures below 1470 K (2186 °F) on a fuel mixture containing 87% hydrogen and 13% natural gas. The tests validated the micro-mixing fuel injector technology and the injectors show great promise for use in future gas turbine engines operating on hydrogen, syngas or other fuel mixtures of various compositions.


2017 ◽  
Author(s):  
Sonawane C. R ◽  
Chintan Kantharia ◽  
Karan Shah ◽  
Neel Patel ◽  
Prikesh Bhatia ◽  
...  

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