Chemistry:R-469A
R-469A is the name given to a refrigerant mixture. It is made up of 35% carbon dioxide (R-744), 32,5 % Difluoromethane (R-32) und 32,5 % Pentafluoroethane (R-125).
History
The mixture was developed by TU Dresden and Weiss Technik (a member of the Schunk Group of companies).[1] Starting point for the development was the restriction in use of the refrigerant Fluoroform (R-23) by EU regulation 517/2014 [2] on fluorinated greenhouse gases. At this time, R-23 was the refrigerant used most often to achieve temperatures of up to –70 °C. Since 2014 R-23 has only been allowed to be used in new refrigerating equipment and devices within the context of transitional regulations. This has led to a significant shortage of the quantity available, among other things, and an enormous increase in price.[3]
The aim of the project was to develop a new refrigerant for temperatures down to –70 °C which fulfils the requirements of the EU regulation and is not combustible or toxic. In 2019 the mixture was registered with ASHRAE for the assignment of an R-number, which was allocated in the same year.[4]
Properties
| Properties | Value[5] |
|---|---|
| Composition |
35% R-744 (CO2) |
| average molar mass [g/mol | 59,1 |
| Bubble point [°C] | −78,5 |
| Dew point [°C] | −61,5 |
R-469A is a chemically stable, transparent and odourless gas mixture.[6] Since it is non-toxic and non-combustible, it has been graded in safety group A1. The global warming potential (GWP) ) of R-469A is 1357 and thus less than 10% of the value for R-23 (GWP 14800[2]). Thanks to the low GWP value it fulfils the requirements of EU regulation 517/2014 on refrigerants for new systems even without the certificate of exemption otherwise necessary. Systems using the refrigerant R-469A up to 3.6 kg filling quantity are exempt from the Leak test in accordance with EU regulation 517/2014.[7]
Use
R-469A is used in test chambers for climate simulation which reach low temperatures of up to –70 °C. It is used as a substitute for R-23. The properties of R-469A with a view to cooling rate, thermal compensation or air distribution are almost identical to those of R-23. This makes the test results of systems using the two refrigerants directly comparable.[8]
Trade names
- WT69
Individual references
- ↑ "Neues Kältemittel ohne R23" (in de-DE). 2019-07-01. https://www.plastverarbeiter.de/87278/neues-kaeltemittel-ohne-r23/.
- ↑ 2.0 2.1 (in German) Verordnung (EU) Nr. 517/2014 des Europäischen Parlaments und des Rates vom 16. April 2014 über fluorierte Treibhausgase und zur Aufhebung der Verordnung (EG) Nr. 842/2006, 2014-05-20, http://data.europa.eu/eli/reg/2014/517/oj/deu, retrieved 2019-12-19
- ↑ BOC (1 September 2019) (in German), Guide to updated EU f-gas regulation (517/2014), p. 8
- ↑ "Publication of approval by ASHRAE". https://www.ashrae.org/File%20Library/Technical%20Resources/Standards%20and%20Guidelines/Standards%20Addenda/34_2019_d_20191118.pdf.
- ↑ ashrae.org: ANSI/ASHRAE Addendum to ANSI/ASHRAE Standard 34-2019, retrieved on 1 January 2020.
- ↑ "Data sheet for WT69 at Weiss Technik". https://www.weiss-technik.com/fileadmin/Redakteur/Weiss/Norway/WT69-Produktblatt-DE.pdf.
- ↑ "Klimatests ohne Leckageprüfung" (in de). 11 July 2019. https://www.laborpraxis.vogel.de/klimatests-ohne-leckagepruefung-a-845717/.
- ↑ "Neues Kältemittel WT69 für Tiefkälte-Anwendungen" (in en). 3 June 2019. https://www.scope-online.de/betriebsmittel/eu-kaeltemittelregulierung-neues-kaeltemittel-wt-69-fuer-tiefkaelte-anwendungen.htm.
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