www.unitense.com Open in urlscan Pro
120.25.84.178  Public Scan

Form analysis
0 forms found in the DOM

Text Content

热门
back to the top
深圳万悟创新电子
   
 * HOME
   
 * | /
 * PRODUCTS
   
   CO2 SENSOR
   REFRIGERANT LEAKAGE DETECTION SENSOR
   HIGH-PRECISE NDIR GAS SENSOR MODULE
   CH4 SENSOR
   INDUSTRIAL GAS SENSOR
   MOS TYPE GAS SENSOR

 * | /
 * ABOUT US
   
   INTRODUCTION
   COMPANY NEWS

 * | /
 * APPLICATIONS
   
 * | /
 * CONTACT
   



 * 中文
   
 * English
   





NDIR GAS SENSOR FOR A2L REFRIGERANT LEAK DETECTION AND MONITORING

2023-06-28 04:45 Unitense


In the United States, to support the Kigali Amendment to the Montreal Protocol
and the Paris Climate Agreement, states have formed alliances to address the
issue of global warming. Its most important goal is to control greenhouse gas
emissions, such as the commonly used hydrofluorocarbon (HFC) refrigerants [1].
According to current policies and measures (as shown in Figure 1), European
Union and North America will stop using refrigerants with a Global Warming
Potential (GWP) greater than 750 from 2024 to 2025. In addition, according to
the "National Plan for China to Implement the Montreal Protocol", China's
control plan of HFCs is also on the agenda.






Figure 1. Regulatory Timeline[2]




Therefore, in response to these government regulations, manufacturers are
developing and manufacturing systems with low GWP refrigerant. The challenge
faced by the products that use alternative HVAC/R refrigerants is that those low
GWP refrigerants typically exhibit more flammable characteristics than
refrigerants designated as ASHRAE A1 safety group. For many existing air
conditioning products that use R-410A, the most promising low-GWP alternatives
include R-32 and R-454B, classified as ASHRAE A2L. Although A2L is slightly more
flammable than traditional A1 refrigerants, it is less flammable than A3
hydrocarbon refrigerants such as R290 (propane) (refer to Figure 2). The
European Union establishes IEC 60335-2-40 standard to specify the design,
evaluation, testing, and certification of HVAC equipment using low-GWP
refrigerants. The corresponding standard in the United States is UL 60335-2-40;
in China, it is GB 4706.32. One of the risks associated with these standards is
refrigerant leakage. Therefore, the standards address the use of refrigerant
leakage detection systems and specifies their qualification specifications.
Especially in UL 60335-2-89, it is clearly stipulated that when the maximum
releasable charge is greater than a certain value, the refrigerant leakage
detection system must be installed indoors or in cabin.



Figure 2. Refrigerant Safety Group[2]




The critical component of the refrigerant leakage detection system is the
refrigerant leakage detection sensor. Currently, sensing technologies for A2L
refrigerant leakage monitoring mainly include non-dispersive infrared (NDIR),
metal oxide semiconductor (MOS, which can be classified as Chemiresistive
principle), and thermal conductivity (TC) technology:

1) The production cost of MOS sensors is very low (due to their simple
principle), but its disadvantages are also prominent. First, the long-term
stability of MOS sensors is poor and prone to lose accuracy over time. Secondly,
MOS sensors have poor selectivity and are easily affected by other volatile
organic compounds (VOC, such as alcohol). The biggest problem is that when
exposed to high concentrations of refrigerants and other gases, MOS sensor
performance will degrade or even permanently fail. It means that MOS sensors are
"disposable" and may require human and material resources to replace sensors
after a refrigerant leak event.

2) Gas sensors using thermal conductivity technology also have the advantage of
low cost. The principle of heat exchange was initially used for flow detection
and is a mature detection technology. However, this technology is not mature for
gas detection yet, and there are no cases of high-volume applications on the
market. Therefore, "to be the first one who eats crabs" is not necessarily the
best choice.

3) NDIR technology is a common way to measure gas concentration and can be used
to detect gases of various compound types. Because it is based on infrared
absorption measurement principles, NDIR gas sensors have high accuracy, fast
response time, and good selectivity. Its disadvantage lies in its high cost.
Regarding the detailed comparison of above detection technologies, and their
pros and cons, please refer to published report from Air-conditioning, Heating
and Refrigeration Technology Institute - "leak detection of A2L refrigerants in
HVACR equipment [3]".







Unitense Innovation's NDIR gas sensor U9601 series and U9603 series can be used
for A2L refrigerant leakage monitoring, such as R32, R454A, R454B, R454C,
R1234yf, etc. The sensor adopts patented optical design, circuit design, digital
signal processing algorithm, and compensation algorithm, has passed multiple
harsh environmental tests and life tests, conforms to IEC60079-29-1:2016 and IEC
60335-2-40:2022, and has superior stability and reliability. The specific
technical information of the sensor can be found in the following product
specification sheet and technical papers. We can provide low-cost customized
solutions at competitive prices according to customer requirements.




A2L Refrigerant Sensor Product Specification




NDIR Gas Sensor Working Principle




Key Characteristics of NDIR Gas sensor







The copyright of this paper belongs to Unitense Innovation. Reproduce is
prohibited.




Reference:




[1] Underwriters' Laboratories, "Understanding UL 60335-2-40 Refrigerant
Detector Requirements",
https://www.ul.com/news/understanding-ul-60335-2-40-refrigerant-detector-requirements,
2019.


[2] Trane Technologies, "HVAC Industry Update",
https://www.trane.com/content/dam/Trane/Commercial/global/newsroom/blogs/REFR-PRB001F-EN_05052020.pdf,
2020.

[3] Mark W and Rebecca F, "leak detection of A2L refrigerants in HVACR
equipment", AHRTI:
https://www.ahrinet.org/sites/default/files/2022-07/AHRTI_9009_Final_Report_0.pdf,
2017





share
WeChat
Sina Weibo
QQ
QQ space
Douban
Baidu Post Bar
Technical Paper
Next Unitense Innovation meets you at Sensor+Test 2023

粤公网安备 44031102000835号

© 深圳万悟创新电子有限公司 版权所有

粤ICP备2022031770号


򡂔
电话咨询：020-000000
򡂐
QQ咨询：258506508
򡂒
微信客服

扫码咨询