Piezoelectric Cooling Device Adiabatic Expansion Cycle
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Solution Overview
Problem
Existing cooling devices, such as piezoelectric micro blowers, are unable to cool a cooling target object to a temperature lower than the environment temperature quickly due to low air flow rates and inability to efficiently lower the temperature of the discharged air.
Innovation Solution
A cooling device with a pump, tank, and valve configuration that compresses and heats gas, then adiabatically expands it to achieve a lower temperature, allowing for high flow rates of cooled air to be directed at the cooling target object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a piezoelectric micro blower is used to cool a cooling target object, then the device size is reduced, but the air flow rate becomes low and the cooling speed decreases
Solution Approach 1:
The cooling device is divided into multiple functional modules: a pump unit for gas compression, a heat dissipation unit for temperature control, and a discharge unit for directed cooling. This segmentation allows each module to be optimized independently, maintaining compact overall size while achieving high cooling efficiency through specialized functions in each segment.
Solution Approach 2:
The pump operates in periodic cycles of compression and expansion, creating pulsating gas flow that is then smoothed through the system. This periodic action enables the compact pump to achieve higher effective flow rates by maximizing the utilization of each compression cycle, thereby increasing cooling speed without increasing device volume.
2Device complexity
If air is discharged directly from the pump to cool the target object, then the device structure is simplified, but the discharged air temperature remains at environment temperature and cannot cool below that threshold
Solution Approach 1:
A heat dissipation unit serving as an intermediary component is introduced between the pump and the cooling target. This intermediary unit actively cools the compressed gas before discharge, enabling the system to achieve temperatures below environment temperature. The added complexity of this intermediary component is justified by the significant improvement in cooling capability.
Solution Approach 2:
The system replaces simple mechanical discharge with a thermodynamic process involving compression, heat dissipation, and controlled expansion. This substitution of mechanical action with thermodynamic cycling enables sub-ambient temperature achievement while maintaining a relatively compact device structure through efficient heat exchange mechanisms.
3Productivity
If the pump chamber volume is increased to提高 air flow rate, then the cooling capacity improves, but the device size increases
Solution Approach 1:
The design compensates for the limited pump chamber volume by implementing a multi-stroke compression mechanism and optimizing the compression ratio. Each unit volume of the pump chamber achieves higher effective gas processing through multiple compression cycles and efficient volumetric utilization, counterbalancing the constraint of small chamber size with enhanced operational efficiency.
Solution Approach 2:
The system achieves higher air flow rates from a compact pump chamber by optimizing compression parameters including pressure ratio, cycle frequency, and temperature management. By carefully controlling these parameters, the small pump chamber processes larger volumes of gas per unit time, maintaining high cooling capacity without increasing device volume.
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
The device effectively cools the cooling target object to a temperature lower than the environment temperature quickly while maintaining a compact size, enhancing cooling efficiency.
Implementation Method 1
when a driving voltage is applied to the piezoelectric element 3, as illustrated in FIGS. 12(b) to 12(e), the diaphragm 2 is bent and deformed with expansion and contraction of the piezoelectric element 3
Implementation Method 2
the gas in the tank is adiabatically expanded, so that the temperature of the gas becomes lower than the environment temperature
Data Source
AI summary
An analyzing device includes a heating device, a cooling device, and a controller. The cooling device includes a piezoelectric pump, a check valve, an exhaust valve, and an air tank. The analyzing device heats a subject by the heating device. The cooling device drives the piezoelectric pump while the heating device heating the subject. With this, the outside air is sucked through a suction port and the air that is discharged from the piezoelectric pump is accommodated in the air tank through the check valve. Then, the pressure in the air tank is increased. Thereafter, the cooling device stops driving of the piezoelectric pump. With this, the air in the air tank is discharged toward the subject via the exhaust valve so as to cool the subject.