Adsorption Compressor Thermal Wave Cycle for High SCP and Compact Size
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Solution Overview
Problem
Existing adsorption heat pump systems using zeolite and water as refrigerant face limitations due to bulky size and reduced specific cooling power (SCP) at low pressures, necessitating improvements in coefficient of performance (COP) and SCP while reducing system size and enhancing efficiency.
Innovation Solution
A method and system that split the adsorption and desorption cycle into four phases, with phases A and C being heat regenerating and phases B and D non-regenerative, allowing for a more uniform thermal wave progression through the adsorption beds, using a heat transfer fluid (HTF) to manage temperature differences and optimize refrigerant adsorption and desorption, and employing specific dimensions for the adsorption material and heat transfer fluid channels to enhance thermal conductivity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water is used as refrigerant in adsorption heat pump systems, then the system can operate at reduced pressures and be environmentally friendly, but the specific cooling power (SCP) is reduced and the system size becomes bulky
Solution Approach 1:
The patent changes the working pressure parameter from reduced pressure to elevated pressure (above atmospheric pressure), which allows water to achieve higher density and improves specific cooling power while maintaining environmental benefits. This parameter change resolves the contradiction by enabling compact system design without sacrificing environmental friendliness.
2Productivity
If thermal wave is applied through adsorption beds, then heat pump efficiency is increased and uniform refrigerant mass flow is provided, but the complexity of temperature control increases
Solution Approach 1:
The patent implements periodic reversal of heat transfer fluid flow direction through the adsorption beds, creating alternating heating and cooling cycles that generate thermal waves. This periodic action maintains high efficiency while simplifying control compared to continuous variable temperature control, as the system operates in discrete on/off cycles.
3Productivity
If the adsorption cycle is split into four phases with heat regenerating and non-regenerative stages, then thermal wave progression is more uniform and efficiency is optimized, but the control system complexity increases
Solution Approach 1:
The four-phase cycle is implemented through periodic reversal of heat transfer fluid flow direction, where phases A and C represent one flow direction and phases B and D represent the reverse direction. This periodic implementation achieves uniform thermal wave progression while maintaining relatively simple control logic based on flow reversal timing.
4Productivity
If fast start-up is achieved in adsorption compressor system, then productivity is improved, but energy consumption during start-up may increase
Solution Approach 1:
The system performs preliminary heating or cooling of the adsorption beds during phase A or C operation before switching to the productive phase. This preliminary action prepares the thermal state of the beds in advance, enabling fast start-up of refrigerant circulation without requiring excessive energy input at the moment of start-up.
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 improves SCP while maintaining a high COP, achieving a compact and efficient adsorption compressor system with enhanced thermodynamic performance and flexibility, allowing for constant cooling or heating production with fast start-up and moderate costs.
Implementation Method 1
heating the first adsorption bed by feeding HTF to it, coming from said second bed, via said hot source, while maintaining a thermal wave in said first bed
Implementation Method 2
The beds in US-A-4 610 148 comprise a zeolite, and the applied refrigerant or adsorbing vapor is water
Implementation Method 3
the water vapor is condensed in a high pressure condenser, and the condensed water is guided through a pressure release valve
Implementation Method 4
the condensed water is guided through a pressure release valve, where due to the Joules Thomson effect, the temperature decreases substantially adiabatically
Implementation Method 5
In a low pressure evaporator, the water is re-evaporated and can be returned through a set of check valves to that adsorption bed that is cold and accepting the vapor to adsorb
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The present invention is directed to a method of operating an adsorption compressor system, which system comprises a hot source and a cold source and at least a first and a second adsorption bed, wherein the first bed has an initial temperature that is lower than the initial temperature of said second bed, in which system heat is circulated using a heat transfer fluid (HTF), the method comprising the following phases: phase A) comprising the steps of: - heating the first adsorption bed by feeding HTF to it, coming from said second bed, optionally via said hot source, while maintaining a thermal wave in said first bed; and - cooling the second adsorption bed by feeding HTF to it, coming from said first bed, optionally via said cold source, while maintaining a thermal wave in said second bed; wherein phase A) is maintained until the exit temperature of said first bed and said second bed are essentially the same and phase B) comprising the steps of: - feeding the HTF effluent of said first bed to said hot source and from said hot source back into said first bed; and - feeding the HTF effluent of said second bed to said cold source and from said cold source back into said second bed; wherein phase B) is maintained until the temperature in said first bed is essentially homogeneous and the temperature in said second bed is also essentially homogeneous and lower than the temperature of said first bed, wherein the flow rates of said HTF through said first and second bed may be higher than in phase A).