Multi-Stage Absorption Heat Pump Without Refrigerant Split
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Solution Overview
Problem
Multi-stage absorption heat pumps face efficiency losses and instability due to refrigerant stream splitting issues, particularly under varying operating conditions, leading to performance reductions and safety concerns.
Innovation Solution
The solution involves eliminating the refrigerant split by passing the entire flow through a heat exchanger where part evaporates, and then separating the vapour and liquid fractions, with the vapour going to the intermediate pressure absorber and the liquid to the evaporator, allowing for self-adaptation of refrigerant quantity based on thermal load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If refrigerant stream splitting is used to enable multi-stage absorption heat pump operation at lower temperatures, then the heat pump can operate at about 50°C less than single effect cycles, but the cycle efficiency is reduced to about one half that of single effect cycles
Solution Approach 1:
The patent implements a dynamic refrigerant distribution system that automatically adjusts the split between the two refrigerant streams based on real-time operating conditions. The distribution mechanism responds to changes in thermal loads, generator input, and pressure conditions, eliminating the need for fixed-geometry splitters and enabling the system to maintain optimal efficiency across varying operating conditions while operating at lower temperatures
Solution Approach 2:
The system dynamically changes the refrigerant flow distribution parameters based on operating conditions. By adjusting the proportion of refrigerant directed to each stream according to actual thermal demands and system state, the patent optimizes the balance between achieving low temperature operation and maintaining high cycle efficiency
2Reliability
If fixed-geometry splitter is optimized for reference conditions, then optimal refrigerant split is achieved at those conditions, but under different operating conditions the splitter causes efficiency losses and periodic oscillations
Solution Approach 1:
The patent replaces static, fixed-geometry splitters with a dynamic distribution system that continuously adapts to changing operating conditions. This dynamic mechanism adjusts refrigerant flow distribution in real-time based on thermal loads, generator input variations, and pressure conditions, eliminating the performance degradation and oscillations that occur with fixed-geometry designs when operating conditions change
3Stability of the object's composition
If refrigerant flow variations occur along splitter outlet branches under transient conditions, then oscillations and instabilities are triggered, but active mechanical splitting systems are complex and difficult to control
Solution Approach 1:
The patent implements a self-regulating refrigerant distribution system that automatically balances flow between branches without requiring complex external control mechanisms. The system uses inherent system parameters such as pressure differences and thermal demands to self-adjust the refrigerant split, eliminating instability and oscillation problems while avoiding the complexity of active mechanical control systems
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 approach stabilizes and enhances the efficiency of the heat pump under variable conditions, reducing efficiency losses and oscillations, and allows the cycle to approach single-effect cycle efficiency under favorable conditions.
Implementation Method 1
passing the entire flow through a heat exchanger where part evaporates
Implementation Method 2
passing the entire flow through a heat exchanger
Implementation Method 3
ammonia, which is absorbed in a second fluid (in this case water)
Data Source
AI summary
An absorption heat pump including a generator or desorber which generates vapour from a first fluid fed to a first condenser, an evaporator provided downstream of the condenser, an outlet of the evaporator connected by a third line to an inlet of a mixer of a low pressure absorber connected to a suction side of a pump feeding solution to the generator. The generator having a poor solution outlet connected by a sixth line provided with at least one lamination valve to a poor solution inlet feeding the absorber. The second line is brought into heat exchange contact with the low pressure absorber and opens into a liquid/vapour separator feeding the evaporator via a third line, the vapour outlet of the separator opening into an intermediate pressure absorber unit.