Microchannel component technology for system-wide application in ammonia/water absorption heat pumps

2011 ◽  
Vol 34 (5) ◽  
pp. 1184-1196 ◽  
Author(s):  
Srinivas Garimella ◽  
Matthew D. Determan ◽  
J. Mark Meacham ◽  
Sangsoo Lee ◽  
Timothy C. Ernst
Keyword(s):  
Water Absorption ◽  
Heat Pumps ◽  
Component Technology ◽  
Ammonia Water

scholarly journals Identification of Existing Challenges and Future Trends for the Utilization of Ammonia-Water Absorption–Compression Heat Pumps at High Temperature Operation

2021 ◽  
Vol 11 (10) ◽  
pp. 4635
Author(s):  
Marcel Ulrich Ahrens ◽  
Maximilian Loth ◽  
Ignat Tolstorebrov ◽  
Armin Hafner ◽  
Stephan Kabelac ◽  
...  
Keyword(s):  
High Temperature ◽  
Water Absorption ◽  
Industrial Sector ◽  
Heat Pumps ◽  
Working Fluid ◽  
Large Temperature ◽  
Future Trends ◽  
Ammonia Water ◽  
Starting Point ◽  
High Temperature Operation

Decarbonization of the industrial sector is one of the most important keys to reducing global warming. Energy demands and associated emissions in the industrial sector are continuously increasing. The utilization of high temperature heat pumps (HTHPs) operating with natural fluids presents an environmentally friendly solution with great potential to increase energy efficiency and reduce emissions in industrial processes. Ammonia-water absorption–compression heat pumps (ACHPs) combine the technologies of an absorption and vapor compression heat pump using a zeotropic mixture of ammonia and water as working fluid. The given characteristics, such as the ability to achieve high sink temperatures with comparably large temperature lifts and high coefficient of performance (COP) make the ACHP interesting for utilization in various industrial high temperature applications. This work reviews the state of technology and identifies existing challenges based on conducted experimental investigations. In this context, 23 references with capacities ranging from 1.4 kW to 4500 kW are evaluated, achieving sink outlet temperatures from 45 °C to 115 °C and COPs from 1.4 to 11.3. Existing challenges are identified for the compressor concerning discharge temperature and lubrication, for the absorber and desorber design for operation and liquid–vapor mixing and distribution and the choice of solution pump. Recent developments and promising solutions are then highlighted and presented in a comprehensive overview. Finally, future trends for further studies are discussed. The purpose of this study is to serve as a starting point for further research by connecting theoretical approaches, possible solutions and experimental results as a resource for further developments of ammonia-water ACHP systems at high temperature operation.

Development of Corrosion Inhibitors for Absorption Heat Pumps

2002 ◽  
Author(s):  
C. L. Hannon ◽  
J. Gerstmann ◽  
F. B. Mansfeld ◽  
Z. Sun
Keyword(s):  
Water Absorption ◽  
Corrosion Inhibitors ◽  
Earth Metal ◽  
Heat Pumps ◽  
Generation Rate ◽  
Sodium Chromate ◽  
Gas Generation ◽  
Ammonia Water ◽  
Steel Surfaces ◽  
Gas Generation Rate

This paper describes the results of a research project to develop a non-toxic corrosion in hibitor for the protection of carbon steel surfaces of ammonia-water absorption heat pumps through the use of rare earth metal salt (REMS) compounds. Chromate compounds are currently used as corrosion inhibitors in these systems, but are toxic, environmentally harmful, and their use is being phased out. Corrosion concerns in ammonia-water absorption systems are primarily those of non-condensable (NC) gases generated by corrosion reactions impeding the heat and mass transfer processes in the system. The research focused on the development of a dual-protection REMS based strategy of applying a cerium-oxide/hydroxide coating to the metal surface in a process called cerating, in conjunction with a cerium-sulfate solution-based inhibitor. A laboratory test was conducted in test rigs designed to simulate the conditions of temperature and ammonia concentration found in the desorber component of advanced ammonia-water absorption systems. The test compared the NC gas generation rate in a rig with cerated steel surfaces to a rig using sodium chromate as a solution based inhibitor. The cerated test rig demonstrated an NC gas generation rate about 3 times lower than that of the chromate protected rig. Neither rig showed any indications of significant corrosion activity. This work has shown that cerating can provide superior suppression of NC gas generation in ammonia-water absorption systems compared to sodium chromate, in a process that is simple and readily applicable to the commercial manufacture of equipment.

Development of Improved Corrosion Inhibitors for Ammonia-Water Absorption Heat Pumps

2000 ◽  
Author(s):  
C. L. Hannon ◽  
J. Gerstmann ◽  
F. B. Mansfeld ◽  
Z. N. Sun
Keyword(s):  
Water Absorption ◽  
Corrosion Inhibitor ◽  
Corrosion Protection ◽  
Corrosion Inhibitors ◽  
Heat Pumps ◽  
Ammonia Decomposition ◽  
Screening Tests ◽  
Ammonia Water ◽  
Surface Pretreatment ◽  
Steel Surfaces

Abstract This paper describes the initial results of a research project to develop an improved corrosion inhibitor for the protection of carbon steel surfaces of ammonia-water absorption heat pumps and chillers using rare earth metal salt (REMS) compounds. Chromate compounds are currently used as corrosion inhibitors, but they are toxic, environmentally harmful, and their use is being phased out in many localities. An effective corrosion inhibitor is needed to make advanced ammonia-water absorption heat pump and chiller systems practical. Low-temperature screening tests were conducted to evaluate the potential of cerium salts, a class of REMS compounds, to act as an inhibitor for steel in ammonia-water solutions. Successful results from these tests led to high-temperature (HT) testing in an innovative test apparatus, which simulated a range of temperatures, ammonia concentrations, and phases typically found in ammonia-water absorption systems. HT testing further demonstrated the effectiveness of cerium nitrate as a corrosion inhibitor, and suggested that it may outperform the Chromate compounds currently used. An additional outcome of the project was the successful demonstration of a cerium based surface pretreatment procedure, termed cerating, as an additional corrosion protection feature. Cerated surfaces will prevent corrosion of steel surfaces and ammonia decomposition at steel surfaces. These results have lead to the concept of a dual corrosion protection strategy utilizing a cerium based solution inhibitor with a cerating surface pretreatment to prevent both corrosion and ammonia decomposition. This approach is presently being pursued in a more intensive study.

Thermodynamic analysis of triple effect ammonia–water absorption compression (hybrid) cycle

2021 ◽  
pp. 095440892199568
Author(s):  
CP Jawahar
Keyword(s):  
Water Absorption ◽  
Energy Analysis ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Performance Parameters ◽  
Evaporator Temperature ◽  
Ammonia Water ◽  
Absorption Cycle ◽  
Hybrid Cycle

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.

scholarly journals Experimental and numerical study of a falling film absorber in an ammonia-water absorption chiller

2017 ◽  
Vol 111 ◽  
pp. 374-385 ◽  
Author(s):  
Delphine Triché ◽  
Sylvain Bonnot ◽  
Maxime Perier-Muzet ◽  
François Boudéhenn ◽  
Hélène Demasles ◽  
...  
Keyword(s):  
Water Absorption ◽  
Numerical Study ◽  
Falling Film ◽  
Absorption Chiller ◽  
Ammonia Water
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