1. Research Background
In fields such as electronic cooling, medical equipment, and portable refrigerators, thermoelectric coolers (TECs) are quietly transforming our lives. As the core parameter for measuring the performance of thermoelectric materials, the ZT value (Figure of Merit) has become a key indicator for technological breakthroughs in the industry.
Congtical has been deeply engaged in the thermal analysis industry for many years, and thermoelectric material testing is one of its permanent research projects. In this process, Chongguang Laboratory has accumulated rich test data and testing experience.
2. Test Results
Previously, Congtical Laboratory selected several mainstream TEC-12704 models available on the market for actual testing, and the test results are as follows:
No. | Supplier (Abbreviation) | Size | ZT Value | Resistance Value (Ω) |
1 | Zhejiang Wan G Semiconductor Co., Ltd. | 30*30MM | 0.752 | 2.671 |
2 | Suzhou Bing X Electronics Co., Ltd. | 40*40MM | 0.703 | 2.668 |
3 | Kun J Cooler | 40*40MM | 0.662 | 2.510 |
4 | Yuxian Zhong T Electronics Co., Ltd. | 40*40MM | 0.662 | 2.589 |
5 | Suzhou Jin X Refrigeration Equipment Co., Ltd. | 40*40MM | 0.592 | 2.622 |
Result Analysis:
- Zhejiang Wan G Semiconductor leads the industry with a ZT value of 0.752.
- Size is not a decisive factor (30mm products outperform 40mm ones).
- There is a weak negative correlation between resistance value and ZT value (resistance is not an absolute indicator).
The ZT values of the thermoelectric coolers in this experiment range from 0.6 to 1.0, while the ZT values of commercial bismuth telluride (Bi₂Te₃) materials usually range from 1.0 to 1.4. This indicates that the energy efficiency of commercially available thermoelectric coolers still has significant room for improvement. Moreover, currently, TEC manufacturers mainly conduct quality inspection for TEC improvement from five aspects: electrical performance, cooling performance, appearance and structure inspection, sealing inspection, and reliability inspection. There is a lack of reflecting the performance of thermoelectric coolers from the perspective of ZT value.
3. Test Principle
The ZT value (Thermoelectric Figure of Merit) is the gold standard for measuring the performance of thermoelectric materials. It comprehensively reflects the relationship between a material’s Seebeck coefficient (thermoelectric power generation capacity), electrical conductivity (conductive efficiency), and thermal conductivity (heat conduction loss). Its calculation formula is:
To achieve a high thermoelectric figure of merit ZT, a material must have a high Seebeck coefficient (S), high electrical conductivity, and low thermal conductivity. This is because the thermoelectric conversion efficiency mainly depends on the figure of merit Z, and the Z value of a thermoelectric material is closely related to its thermophysical parameters (Seebeck coefficient, electrical conductivity, thermal conductivity). The dimensionless figure of merit ZT is usually used as an evaluation indicator for the performance of thermoelectric materials.
In simple terms:
- ✅ High ZT value = Stronger cooling capacity + Lower energy consumption
- ❌ Low ZT value = Low cooling efficiency + High power consumption
4. Test Method
A constant current is applied to the sample. According to the Peltier effect, the thermoelectric material will absorb heat at one end and release heat at the other, generating a temperature difference voltage (Vₛ). When the temperature difference and heat conduction reach equilibrium, the voltage at this point (Vₜ) is recorded. Vₜ includes the voltage across the device’s resistance (Vᵣ) and Vₛ. Then, the current is cut off: Vᵣ disappears immediately, while Vₛ decreases gradually. The voltage change curve before and after this moment is recorded, and data analysis methods are used to determine Vᵣ. The ratio Vₛ / Vᵣ represents the ZT value of the device.
5. Test Equipment
Congtical Thermoelectric Parameter Analyzer (TPA) is a high-end instrument capable of room-temperature measurement of the Seebeck coefficient of thermoelectric materials, as well as measurement of the ZT value and resistance value of thermoelectric coolers. It can help you quickly calculate the ZT value and provide reliable data support for material research and development (R&D) and product optimization, making it an important tool for the research, development, and production of thermoelectric materials and devices.
☞ Technical Parameters for ZT Value Measurement of Thermoelectric Coolers
- ZT value measurement range: 0-2
- Supports testing of various thermoelectric materials such as Bi₂Te₃, PbTe, and SiGe.
☞ Application Scenarios
- Suitable for laboratory R&D (material screening)
- Supports production line quality control (batch testing)
6. Conclusion
As a leading enterprise in the field of thermoelectric testing, Wuhan Congtical Technology Co., Ltd. has always been committed to providing customers with high-quality products and services. Our testing instruments have served:
- More than 30 universities and research institutes
- More than 10 corporate R&D centers
- More than 100 thermoelectric cooler manufacturers
If you belong to any of the following groups:
- Thermoelectric cooler manufacturers
- New energy material R&D institutions
- Electronic equipment manufacturers
Please feel free to contact us! Wuhan Congtical Technology Co., Ltd. is dedicated to providing you with professional technical support and solutions.
