Energy, exergy, and economic analysis of single and double effect LiBr–H2O absorption chillers

2014 ◽  
Vol 73 ◽  
pp. 26-36 ◽  
Author(s):  
T. Avanessian ◽  
M. Ameri
2001 ◽  
Author(s):  
E. D. Rogdakis ◽  
V. D. Papaefthimiou

Abstract It is a general trend today, the old centrifugal machines to be replaced by new absorption machines. The mass flow rate of the cooling water in the centrifugal machines is normally 30% less than that in the two-stage absorption chiller for the same refrigerating capacity. Some absorption chillers manufacturers have updated and improved the double-effect technology increasing the cooling water temperature difference from the typical value of 5.5°C to 7.4°C and reducing the cooling water flow rate by about 30%. Using such a modern double effect absorption unit to replace a centrifugal chiller the same cooling water circuit can be used and the total cost of the retrofit is minimized. In this case a new flow pattern of the cooling tower is developed, and in this paper the design of a new tower fill is predicted taking into account the new factors characterizing the operating conditions and the required performance of the tower. As an example, the operational curves of a modified cooling tower (1500 KW cooling power) used by a 240 RT double-effect absorption chiller are presented.


2021 ◽  
pp. 58-58
Author(s):  
Farshad Panahizadeh ◽  
Mahdi Hamzehei ◽  
Mahmood Farzaneh-Gord ◽  
Villa Ochoa

Absorption chillers are one of the most used equipment in industrial, commercial, and domestic applications. For the places where high cooling is required, they are utilized in a network to perform the cooling demand. The main objective of the current study was to find the optimum operating conditions of a network of steam absorption chillers according to energy and economic viewpoints. Firstly, energy and economic analysis and modeling of the absorption chiller network were carried out to have a deep understanding of the network and investigate the effects of operating conditions. Finally, the particle swarm optimization search algorithm was employed to find an optimum levelized total costs of the plant. The absorption chiller network plant of the Marun Petrochemical Complex in Iran was selected as a case study. To verify the simulation results, the outputs of energy modeling were compared with the measured values. The comparison with experimental results indicated that the developed model could predict the working condition of the absorption chiller network with high accuracy. The economic analysis results revealed that the levelized total costs of the plant is 1730 $/kW and the payback period is three years. The optimization findings indicated that working at optimal conditions reduces the levelized total costs of the plant by 8.5%, compared to the design condition.


Author(s):  
Daniele Ludovisi ◽  
William M. Worek ◽  
Milton Meckler

Multi-effect LiBr absorption chiller must take advantage of higher temperature heat sources to achieve higher COP so as to be competitive with lower first cost comparable commercially available, efficient electric chillers under current market pricing conditions. Yet a nominal conventional double-effect absorption chiller operating at a COP of 1.0 versus a comparable efficient motor driven centrifugal chiller operating at a COP of 7.0 will consume slightly less than twice the amount of prime natural gas (NG) source energy assuming a local 28% NG fired electric utility plant’s annual average efficiency and a 10% gas distribution leakage and 10% electric transmission loss to user’s meter. However if the COP of the above referenced double-effect LiBr absorption chiller were doubled, it would consume approximately the same amount of prime NG source energy and equally sustainable from an environmental impact standpoint. Consequently research to further improve double-effect LiBr absorption chillers beyond the VRA benefits reported to date was investigated in this study. Former simulation studies of a low differential pressure-vapor recompression absorber (VRA) reported in 2001 indicated a 7% COP efficiency gain, while additional simulation studies reported in 2006 indicated a 38% COP efficiency gain with the VRA operating at elevated differential pressures at the same upper stage concentrator temperature previously considered. Double-effect LiBr absorption chillers are limited by corrosion effects, which have been shown to accelerate significantly above 160 °C. In this paper, a reverse series flow, double-effect LiBr absorption chiller employing a VRA is investigated over a wider range of upper stage concentrator and absorber cooling temperatures but operating at the same low and elevated pressure differential levels reported earlier showed significant improvement in COP efficiency, capacity performance and projected hybrid operational cost.


2013 ◽  
Vol 465-466 ◽  
pp. 327-334
Author(s):  
Morteza Khalaji Assadi ◽  
Hamidreza Akhavan Armaki ◽  
Mahmoud Zendeh Del

The aim of this research is to indicate a steam double effect chiller-heater equipped with solar heat pipe in a certain space with the area of 975 m2 located in Tehran, which is currently equipped with a direct-fired single effect absorption chiller-heater. Thereafter , the most obvious differences of the two chiller-heater systems are compared: the solar cooling system increases coefficient of performance as high as 0.54, decreases CO2 dissemination by 829 tons in each year, and reduces energy consumption by 1552.42 MWh/Yr. Economic analysis of the two systems using break-even-point showed that the use of solar system is attractive in applications that have excess thermal energy, and the conversion of this energy to higher value energy markets is to be more profitable than absorption gas-fired system from 13th year on. Keywords: Technical-economic analysis, energy optimization, solar chiller, absorption chiller-heater, solar heat pipe.


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