Sorption Heat Pump Circuit With Multi-Stage Expellers
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Solution Overview
Problem
Sorption heat pumps and cycle processes fail to utilize a significant portion of heat available in the rich solution to preheat the depleted solution, leading to suboptimal energetic efficiency and initial temperature in the absorber.
Innovation Solution
Incorporating a second expeller to absorb heat from the rich solution and expel additional gaseous refrigerant, along with a second pump and compressor for enhanced compression, and utilizing a low-pressure expeller and solution heat exchanger to further increase heat recovery and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single expeller is used to expel refrigerant from rich solution, then the system structure is simple, but the initial temperature of the medium heated in the absorber is limited and energy efficiency is suboptimal
Solution Approach 1:
The single expeller function is segmented into multiple expellers operating at different pressure levels. The first expeller operates at high pressure to expel refrigerant at a higher temperature, directly increasing the initial temperature of the medium heated in the absorber. The second expeller operates at medium pressure to recover additional heat. This segmentation allows the system to utilize heat at multiple temperature levels, thereby increasing both the initial temperature in the absorber and overall energy efficiency.
Solution Approach 2:
The system transitions from a single-pressure-level expeller to a multi-pressure-level expeller configuration. By adding the pressure dimension, the system can extract heat at different pressure levels (high pressure from first expeller, medium pressure from second expeller), creating a three-dimensional heat recovery approach (temperature, pressure, and heat flow direction) that simultaneously increases absorber temperature and energy efficiency without excessive structural complexity.
2Loss of energy
If more heat is recovered from the rich solution using additional expellers, then energy efficiency increases, but the device complexity and number of components increase
Solution Approach 1:
The depleted solution from the first expeller serves multiple functions: it is pumped back to the absorber for refrigerant absorption, and simultaneously serves as the heat source medium for the second expeller. This multi-functionality allows the system to recover heat at two different pressure levels using the same solution circulation, increasing energy efficiency without proportionally increasing the number of independent components.
Solution Approach 2:
The system merges the refrigerant circulation loop with the heat recovery loop by using the depleted solution from the first expeller as the heat source for the second expeller. This integration allows simultaneous refrigerant expulsion at high temperature and heat recovery at medium temperature, maximizing energy utilization while minimizing additional component requirements.
3Use of energy by moving object
If the refrigerant is compressed from low-pressure to high-pressure in one stage, then the compression process is simple, but the compression work and energy consumption are high
Solution Approach 1:
The single-stage compression process is segmented into two stages: first-stage compression from low pressure to medium pressure, and second-stage compression from medium pressure to high pressure. The first-stage compressor receives refrigerant from the first expeller and compresses it to medium pressure. The second-stage compressor then compresses the medium-pressure refrigerant to high pressure. This segmentation reduces the compression ratio per stage, thereby reducing compression work and energy consumption.
Solution Approach 2:
The medium-pressure level acts as an intermediary state between low-pressure and high-pressure compression. By introducing this intermediate pressure level, the system avoids direct high-ratio compression, allowing for more efficient compression processes. The intermediary pressure level also enables heat recovery at an intermediate temperature level, further improving energy efficiency.
4Productivity
If the initial temperature of the medium heated in the absorber is increased, then the heat recovery potential increases, but the system requires more complex heat utilization mechanisms
Solution Approach 1:
The system maintains continuous useful action by ensuring that heat is recovered at multiple stages without interruption. The first expeller continuously expels refrigerant at high temperature to heat the medium in the absorber, while the second expeller simultaneously recovers heat from the depleted solution. This continuous multi-stage heat recovery maximizes heat utilization potential while using straightforward expansion and heat exchange mechanisms rather than complex variable-parameter 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 configuration increases the initial temperature of the medium heated in the absorber and enhances energy efficiency by effectively utilizing internally generated heat to increase the concentration difference between rich and lean solutions, reducing refrigerant compression effort and leveraging low-temperature heat for additional refrigerant expulsion.
Implementation Method 1
the depleted solution absorbs heat from the rich solution and thereby expels gaseous refrigerant
Implementation Method 2
expels second gaseous refrigerant (23) from the depleted solution (22)
Implementation Method 3
the separated second refrigerant (23) is compressed in a second compressor (34) to the high-pressure level (16)
Implementation Method 4
the remaining depleted solution (22) is pumped into the absorber (29)
Implementation Method 5
an absorber (2) in which the depleted solution absorbs the refrigerant and giving off heat
Implementation Method 6
the separated second refrigerant (23) is compressed in a second compressor (34) to the high-pressure level (16), thereby being further heated and also pumped into the absorber (29)
Implementation Method 7
a throttle valve (3) that expands the rich solution
Data Source
Figure 1a~1b
Figure 2a
Figure 2b
AI summary
First, a sorption heat pump (18) with gaseous refrigerant and liquid solvent, a depleted and a rich solution, the depleted and the rich solution being single-phase mixtures of the solvent and the refrigerant, and with an absorber (29) in which the depleted Solution absorbs the refrigerant and gives off heat, a throttle valve (30) that expands the rich solution, an expeller in which the rich solution absorbs heat and thereby expels the refrigerant, a compressor (32) that compresses the refrigerant, and a Pump (26), which pumps the depleted solution, with pipelines in this order the absorber (29), the throttle valve (30) and the expeller and parallel to each other on the one hand the compressor (32) and on the other hand the pump (26) to form a circular closed connect system. The invention further relates to a sorption cycle process for operating such a sorption heat pump (18). In order to increase the energy efficiency and the initial temperature of the medium heated in the absorber, it is proposed to provide a second expeller (27) behind the expeller, in which the depleted solution absorbs heat from the rich solution and thereby expels the second gaseous refrigerant.