Study on a twin-bed adsorption refrigeration system using R134a-activated carbon pair

This paper presents adsorption and desorption characteristics of two different working pairs—activated carbon–methanol and activated carbon–R134a—determined experimentally. Dubinin–Radushkevich (D–R) equation is used to correlate the adsorption isotherms and to form the pressure, temperature, and concentration diagrams for both the assorted working pairs. The results show that the maximum adsorption capacity of activated carbon–R134a working pair is 1.21 times that of activated carbon–methanol. Temperature and pressure distribution throughout the adsorbent bed and their variation with adsorption time are also predicted. Use of artificial neural network (ANN) is proposed to determine the uptake from measured pressure and temperature. The back propagation algorithm with three different variants, namely, scaled conjugate gradient (SCG), Pola–Ribiere conjugate gradient (CGP), and Levenberg–Marquardt (LM) and logistic sigmoid transfer function are used, so that the best approach could be found out. After training, it is found that LM algorithm with 11 neurons is the most suitable for modeling adsorption refrigeration system. The adsorption and desorption uptake obtained experimentally are compared with the uptake predicted by D–R equation and ANN modeling.

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Study on Solar Energy for Pre-Cooling Technology of Fruit and Vegetable

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.700.37 ◽

2014 ◽

Vol 700 ◽

pp. 37-41

Author(s):

A Min Ji ◽

Tian Tian ◽

Bo Ning Tang

Keyword(s):

Mathematical Model ◽

Activated Carbon ◽

Solar Energy ◽

System Performance ◽

Refrigeration System ◽

Adsorption Refrigeration ◽

Vacuum Tube ◽

Rate Versus ◽

Adsorption Temperature ◽

Cooling Technology

This paper discusses the importance of per-cooling vegetable and fruit, establishes a mathematical model of the solar adsorption refrigeration system collector bed. It applies activated carbon - methanol as working pairs, takes solar vacuum tube－water cooled collector bed for refrigerating, adsorption temperature and adsorption rate versus time are calculated , draw the corresponding curve figure. Analyses solar adsorption refrigeration system performance and puts forward the improvement direction.

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Performance Study of Solar Adsorption Refrigeration System Using Activated Carbon - Methanol

Al-Nahrain Journal for Engineering Sciences ◽

10.29194/njes.21040523 ◽

2018 ◽

Vol 21 (4) ◽

pp. 523-531

Author(s):

Wissam H. Khaleel ◽

Abdul Hadi N. Khalifa ◽

Hilal Tareq Abdulazeez

Keyword(s):

Activated Carbon ◽

Solar Energy ◽

Adsorption Process ◽

Energy Sources ◽

Refrigeration System ◽

Performance Study ◽

Adsorption Refrigeration ◽

New Techniques ◽

Conservation Of Energy ◽

Harmful Effects

The depleting of the conventional sources of energy and the excess use of HCF components lead to the need for new techniques both for conservation of energy sources for the future and for decreasing the its harmful effects on the environment. This study investigated the adsorption capabilities of activated carbon. The adsorption of methanol on this substance was tested for their application in the adsorption refrigeration system based on solar energy. Adsorption refrigeration system has been designed and manufactured with the energy source being solar energy. Methanol/activated carbon pairs have been used in experiments. The present work focused on the performance of the adsorption refrigeration system considering the temperature attained in the evaporator and the cooled spaced cabinet. The amounts of activated carbon used was (8 kg), while the amount of methanol were (1, 1.25, and 1.5) kg. The experiments were done in different days of the year. The amount of adsorption of methanol (as a result of decreasing the evaporator and cooled spaced temperature) was found to depend on the generator pressure and its increase as the primary generator pressure decreases. The best mass of methanol used was (1 kg) which give the lowest temperature obtained at the evaporative surface was ( 3.4 oC ) at the day ( 4/4/2017 ). The results shown that even in cloudy days there is a benefit from using such a system because the temperature attained is enough to start the adsorption process. The lowest temperature obtained at the evaporative surface was (3.4 oC) at the day (4/4/2017) for methanol mass of (1 kg) at an opening time of the valve between the evaporator and the generator (9:30am). The increase of methanol amount used in the experiment led to a good decrease in temperature attained in cooled spaced, but this is related to the time of connecting the evaporator and generator.

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Influence of initial bed temperature on bed performance of an adsorption refrigeration system

Thermal Science ◽

10.2298/tsci160108254s ◽

2018 ◽

Vol 22 (6 Part A) ◽

pp. 2583-2595 ◽

Cited By ~ 1

Author(s):

Anirban Sur ◽

Randip Das ◽

Ramesh Sah

Keyword(s):

Activated Carbon ◽

Cycle Time ◽

Cooling System ◽

Cooling Capacity ◽

Heat Transfer Fluid ◽

Low Grade ◽

Refrigeration System ◽

Adsorption Refrigeration ◽

Bed Temperature ◽

Engineering Department

The study deals with the complete dynamic analysis (numerical and practical) of an existing adsorption refrigeration system. The adsorption refrigeration setup is available at Indian School of Mines (Dhanbad, India), Mechanical engineering department. The system operates with activated carbon (as an adsorbent) and methanol (as refrigerant).Numerical model is established base on energy equation of the heat transfer fluid (water) and transient heat and mass transfer equations of the adsorbent bed. The input temperature of heat source is 90?C, which is very low compared to other low-grade energy input refrigeration system. The thermo-physical properties of an adsorptive cooling system (using activated carbon?methanol pair) are considered in this model. In this analysis influence of initial bed temperature (T1) on the bed performances are analysed mathematically and experimentally. The simulation and practical results of this system show that the cycle time decreases with increase in initial bed temperature and the minimum cycle time is 10.74 hours (884 minutes for practical cycle) for initial bed temperature of 40?C. Maximum system COP and specific cooling capacity are 0.436 and 94.63 kJ/kg of adsorbent under a condenser and evaporator temperatures of 35?C and 5?C, respectively. This analysis will help to make a comparison between simulated and experimental results of a granular bed adsorption refrigeration system and also to meet positive cooling needs in off-grid electricity regions.

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