Double-Effect Absorption Chiller-Heater With Dual-Generator Heat Recovery
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Solution Overview
Problem
Existing vapor absorption chiller-heater systems are inefficient in producing hot water and refrigeration simultaneously, often requiring excessive fuel input and additional electrical or heat sources, and are costly due to complex constructions and the use of chlorofluorocarbons, which increase carbon dioxide emissions.
Innovation Solution
The system incorporates a high temperature generator, hot-water heat exchanger, high temperature heat exchanger, low temperature generator, low temperature heat exchanger, recovery heat exchanger, condenser, evaporator, and absorber, with optional heat reclaimer, allowing for efficient heat transfer and recycling to produce hot water and refrigeration without additional electrical or heat inputs, using a water-lithium bromide refrigerant pair and heat inputs from steam or fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional vapor absorption chiller-heater systems are used to produce hot water and refrigeration simultaneously, then heating and cooling functions are provided, but fuel consumption is excessive and system efficiency is low
Solution Approach 1:
The system divides the absorption cycle into two separate generators: a high-temperature generator (receives steam or hot water) and a low-temperature generator (receives waste heat or exhaust gases). This segmentation allows each generator to operate at optimal temperature ranges, improving overall efficiency and reducing fuel consumption while maintaining simultaneous heating and cooling capabilities
Solution Approach 2:
The patent merges the heating and refrigeration cycles into a single integrated absorption system where both functions share common components (condenser, evaporator, absorber). The high-temperature generator provides both process heating and drives the refrigeration cycle, while the low-temperature generator utilizes waste heat to further enhance cooling capacity, thereby reducing total fuel input
2Productivity
If conventional vapor absorption systems use additional electrical or heat sources to improve efficiency, then system performance increases, but initial capital investment and operational complexity increase
Solution Approach 1:
The absorption system is designed to accept multiple heat source types (steam, hot water, waste heat, exhaust gases) through a universal thermal input interface. The dual-generator configuration can operate in various modes depending on available heat sources, providing multi-functionality without requiring additional electrical components or complex control systems
Solution Approach 2:
The system utilizes waste heat and exhaust gases from industrial processes as primary heat sources for both the high- and low-temperature generators. This self-service approach captures otherwise lost thermal energy to drive the chiller-heater system, eliminating the need for additional fuel input or electrical power while reducing operational complexity
3Productivity
If chlorofluorocarbon refrigerants are used in chiller systems, then refrigeration effect is achieved, but carbon dioxide emissions increase and environmental harm occurs
Solution Approach 1:
The system employs an alternative refrigerant pair (ammonia-water or hydrocarbon-water) that replaces chlorofluorocarbon-based refrigerants. This parameter change in refrigerant composition eliminates ozone-depleting substances and reduces greenhouse gas emissions while maintaining effective refrigeration capacity through the absorption cycle mechanism
Solution Approach 2:
The system converts waste heat and exhaust gases, which would otherwise be harmful emissions contributing to environmental pollution, into useful thermal energy to drive the refrigeration and heating processes. This transforms harmful waste streams into beneficial resources, reducing overall carbon footprint while maintaining productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration achieves 30-40% better efficiency than conventional systems, reduces fuel consumption, eliminates the need for chlorofluorocarbons, and decreases carbon dioxide emissions, while providing effective heating and refrigeration with reduced initial capital investment and operational costs.
Implementation Method 1
the high temperature generator, to receive a heated absorbent solution having concentration between 50-62% from the high temperature heat exchanger, being adapted to boil the absorbent solution using heat input having temperature between 130-220° C., to provide a heated absorbent solution having concentration between 57-64%
Implementation Method 2
the hot-water heat exchanger, to receive a portion of the refrigerant vapors from the high temperature generator, being adapted to transfer the heat there from to water, to provide hot water having temperature between 45-95° C., condensing the refrigerant vapors to form a refrigerant condensate
Implementation Method 3
the low temperature generator, to receive a portion of the refrigerant vapors from the high temperature generator, and a partly heated absorbent solution having concentration between 50-62% from at least one equipment selected from the group consisting of the high temperature heat exchanger, the low temperature heat exchanger, and the recovery heat exchanger, being adapted to use the heat from the refrigerant vapors to boil the absorbent solution
Implementation Method 4
the low temperature heat exchanger, to receive a heated absorbent solution having concentration between 57-64% from the low temperature generator, being adapted to transfer heat to the dilute absorbent solution, to provide a concentrated cooled absorbent solution having concentration between 57-64%
Implementation Method 5
the recovery heat exchanger, to receive the cooled absorbent solution having concentration between 50-57% from the absorber, and the refrigerant condensate from at least one equipment selected from the group consisting of the low temperature generator and the hot-water heat exchanger, being adapted to extract heat from the refrigerant condensate to the absorbent solution
Implementation Method 6
the absorber, cooperating with the evaporator to receive the refrigerant vapors, wherein the cooled absorbent solution having concentration between 62-64% is sprayed in the absorber, being adapted to absorb the refrigerant vapors, causing the absorbent solution to dilute
Implementation Method 7
the evaporator, in which, the further condensed cooled refrigerant absorbs heat from the water to form refrigerant vapors, providing chilled water having temperature between 0-10° C.
Data Source
AI summary
The absorption chiller-heater apparatus of present invention utilizes a portion of direct heat, used to heat water, for providing the refrigeration effect. The external heat input required for providing refrigeration is minimal; hence, the efficiency of the apparatus is increased by 30-40% over the conventional systems. Further, as the quantum of the external heat source required for a new cycle is reduced, the size of the high temperature generator required, is smaller, which results in lower capital costs. The apparatus provides chilled water which can be used for various industrial purposes. The absorption chiller-heater reduces CO2 emissions and utilizes a single arrangement to produce both heating and refrigeration effect. Thus, additional electrical and heat input or separate components are not required.