The influence of the generator and bubble pump configuration on the performance of diffusion absorption refrigeration (DAR) system

This paper presents the design and experimental analysis of a compact Diffusion Absorption Air Cooler (DAAC) system, in which the Diffusion Absorption Refrigeration (DAR) technology is utilized. The system uses a bubble pump to replace the mechanical pump, uses three-component working fluid (NH3+H2O+He), and operates under the same system pressure level. Hence, it is quiet, long lasting and environmental friendly. To investigate the practicality of using the DAAC system for regional air conditioning, the thermodynamic model is derived to guide the system design first, and then a DAAC experimental prototype is built for validation. Since the bubble pump is the kernel component, a series of experiments are conducted to investigate the bubble pump performance. From the experimental results under various operation conditions, it is found that the bubble pump dominates the system performance and should be designed carefully to match the designed cooling capacity and operation condition. The experimental results also show that the DAAC can work smoothly under various ambient temperatures when the input power of bubble pump is over 200W.

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MODELING OF BOILING TWO-PHASE FLOW IN THE BUBBLE PUMP OF DIFFUSION-ABSORPTION REFRIGERATION CYCLES

Chemical Engineering Communications ◽

10.1080/00986445.2013.828608 ◽

2014 ◽

Vol 202 (1) ◽

pp. 15-24 ◽

Cited By ~ 2

Author(s):

Ali Benhmidene ◽

Bechir Chaouachi ◽

Slimane Gabsi ◽

Mahmoud Bourouis

Keyword(s):

Two Phase Flow ◽

Phase Flow ◽

Absorption Refrigeration ◽

Two Phase ◽

Diffusion Absorption ◽

Bubble Pump

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Design and construction of a low capacity pump-less absorption system

Thermal Science ◽

10.2298/tsci120119016m ◽

2014 ◽

Vol 18 (2) ◽

pp. 577-590

Author(s):

Hamed Monsef ◽

Naghash Zadegan ◽

Koroush Javaherdeh

Keyword(s):

Electrical Power ◽

Solution Concentration ◽

Absorption Refrigeration ◽

Refrigeration System ◽

Absorption System ◽

Horizontal Tubes ◽

Mechanical Pump ◽

Absorption Refrigeration System ◽

The Cost ◽

Bubble Pump

In this investigation, a low capacity absorption system has been designed and constructed where the mechanical pump has been replaced with a bubble pump, reducing the cost and eliminating the electrical power. Initially, a test rig bubble pump has been built with a single Pyrex tube to test the effect of different parameters on pumping flow rate. An absorption refrigeration system with a capacity of 2.5 kW has been designed and constructed. Results have shown that a bubble pump with five horizontal tubes with 2.5 mm diameter and submergence ratio of 0.4 has the best performance for this low capacity absorption refrigeration system. The COP of this structure was about 0.51 and mathematical modeling shows that increasing the solution concentration at generator outlet decreases the COP of the system.

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A Parametric Examination of the Factors Affecting the Performance of a Diffusion Absorption Refrigeration System

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4052349 ◽

2021 ◽

pp. 1-38

Author(s):

Noman Yousuf ◽

Timothy Anderson ◽

Roy Nates

Keyword(s):

Waste Heat ◽

Operating Conditions ◽

Design Parameters ◽

Working Fluid ◽

Low Grade ◽

Absorption Refrigeration ◽

Factors Affecting ◽

Thermally Driven ◽

Mass Flowrate ◽

Diffusion Absorption

Abstract Despite being identified nearly a century ago, the diffusion absorption refrigeration (DAR) cycle has received relatively little attention. One of the strongest attractions of the DAR cycle lies in the fact that it is thermally driven and does not require high value work. This makes it a prime candidate for harnessing low grade heat from solar collectors, or the waste heat from stationary generators, to produce cooling. However, to realize the benefits of the DAR cycle, there is a need to develop an improved understanding of how design parameters influence its performance. In this vein, this work developed a new parametric model that can be used to examine the performance of the DAR cycle for a range of operating conditions. The results showed that the cycle's performance was particularly sensitive to several factors: the rate of heat added and the temperature of the generator, the effectiveness of the gas and solution heat exchangers, the mass flowrate of the refrigerant and the type of the working fluid. It was shown that can deliver good performance at low generator temperatures if the refrigerant mass fraction in the strong solution is made as high as possible. Moreover, it was shown that a H2O-LiBr working pair could be useful for achieving cooling at low generator temperatures.

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