PERFORMANCE EVALUATION OF COMPRESSOR ASSISTED MULTI-EFFECT ABSORPTION REFRIGERATION CYCLES WITH AMMONIA-WATER AS WORKING PAIR FOR COOLING AND POWER /
Okwose, Chinedu Frank
PERFORMANCE EVALUATION OF COMPRESSOR ASSISTED MULTI-EFFECT ABSORPTION REFRIGERATION CYCLES WITH AMMONIA-WATER AS WORKING PAIR FOR COOLING AND POWER / Chinedu Frank OKWOSE; Supervisor: Asst. Prof. Dr. Muhammed Abid - 138 sheets; 30 cm.
Thesis (PHD) - Cyprus International University. Institute of Graduate Studies and Research Energy Systems Engineering Department
Includes bibliography (sheets 126-138)
ABSTRACT
Absorption refrigeration cycles are energy saving plants as they can be driven by waste heat instead of electricity. By doing so, they reduce the use of fossil fuels, resulting in a reduction of emissions. Absorption refrigeration systems are a great alternative to the conventional compression refrigeration systems when a low-grade waste heat is available to drive the cycle. The combined production of electricity (decentralized) and cold using efficient thermally-driven energy conversion systems are one of the suitable technological solution to address the current global energy-related challenges. The inlet temperature required for the operation of these systems can also be reduced to enable operation in instances when the available temperature is lower.
In this thesis, several new combined absorption cycle configurations were proposed for the simultaneous and/or alternative production of mechanical power and cold by using low and mid-grade heat sources. The systems can operate in 3 different modes; the cold mode, the co-production mode, and the power only mode.
The performance of each of the systems was analyzed and discussed from the energetic and exergetic viewpoints. The effective efficiency is derived by converting the cooling output to an equivalent mechanical power using a reference efficiency derived from literature. The results of the study showed that the inlet temperature of the single effect combined absorption refrigeration and power (SECARP) system can be reduced by about 23.4% and the system is able to operate at 97 oC as a result of the compressor addition.
The double effect combined absorption refrigeration and power system (DECARP) system generates 54.8 kW of cold and 20.57 kW of expander work. The compression in the system also takes up 3.496 kW which gives a net output of 6.43 kW. The inlet temperature reduction is from 178.8 oC to 149.6 oC. The effective energy efficiency of this system at this co-production mode is 9.6% and its effective exergy efficiency is 35.94%.
The triple effect combined absorption refrigeration and power (TECARP) system was able to reduce its inlet temperature requirement from 228 oC to 156 oC, representing a 33% reduction. In the co-production mode, the system produces 64.55 kW of cooling and a net power of 7.3 kW. Its compressor requires 4.121 kW which is extracted from the 13.45 kW produced by the expander.
This study’s results can assist manufacturers in designing systems capable of providing cooling and power simultaneously, at varying loads, and at reduced inlet temperatures.
Cooling--Dissertation, Academic
Power--Dissertation, Academic
Performance--Dissertation, Academic
PERFORMANCE EVALUATION OF COMPRESSOR ASSISTED MULTI-EFFECT ABSORPTION REFRIGERATION CYCLES WITH AMMONIA-WATER AS WORKING PAIR FOR COOLING AND POWER / Chinedu Frank OKWOSE; Supervisor: Asst. Prof. Dr. Muhammed Abid - 138 sheets; 30 cm.
Thesis (PHD) - Cyprus International University. Institute of Graduate Studies and Research Energy Systems Engineering Department
Includes bibliography (sheets 126-138)
ABSTRACT
Absorption refrigeration cycles are energy saving plants as they can be driven by waste heat instead of electricity. By doing so, they reduce the use of fossil fuels, resulting in a reduction of emissions. Absorption refrigeration systems are a great alternative to the conventional compression refrigeration systems when a low-grade waste heat is available to drive the cycle. The combined production of electricity (decentralized) and cold using efficient thermally-driven energy conversion systems are one of the suitable technological solution to address the current global energy-related challenges. The inlet temperature required for the operation of these systems can also be reduced to enable operation in instances when the available temperature is lower.
In this thesis, several new combined absorption cycle configurations were proposed for the simultaneous and/or alternative production of mechanical power and cold by using low and mid-grade heat sources. The systems can operate in 3 different modes; the cold mode, the co-production mode, and the power only mode.
The performance of each of the systems was analyzed and discussed from the energetic and exergetic viewpoints. The effective efficiency is derived by converting the cooling output to an equivalent mechanical power using a reference efficiency derived from literature. The results of the study showed that the inlet temperature of the single effect combined absorption refrigeration and power (SECARP) system can be reduced by about 23.4% and the system is able to operate at 97 oC as a result of the compressor addition.
The double effect combined absorption refrigeration and power system (DECARP) system generates 54.8 kW of cold and 20.57 kW of expander work. The compression in the system also takes up 3.496 kW which gives a net output of 6.43 kW. The inlet temperature reduction is from 178.8 oC to 149.6 oC. The effective energy efficiency of this system at this co-production mode is 9.6% and its effective exergy efficiency is 35.94%.
The triple effect combined absorption refrigeration and power (TECARP) system was able to reduce its inlet temperature requirement from 228 oC to 156 oC, representing a 33% reduction. In the co-production mode, the system produces 64.55 kW of cooling and a net power of 7.3 kW. Its compressor requires 4.121 kW which is extracted from the 13.45 kW produced by the expander.
This study’s results can assist manufacturers in designing systems capable of providing cooling and power simultaneously, at varying loads, and at reduced inlet temperatures.
Cooling--Dissertation, Academic
Power--Dissertation, Academic
Performance--Dissertation, Academic