多年來，使用易燃制冷劑——例如 A3 碳?xì)浠衔?R-290（或丙烷）——一直是管理商業(yè)制冷制冷劑安全標(biāo)準(zhǔn)的監(jiān)管機(jī)構(gòu)共同關(guān)注的熱點(diǎn)領(lǐng)域。這種天然制冷劑具有出色的能源效率和極低的 GWP，長期以來一直被批準(zhǔn)用于最大充注量為 150 克的應(yīng)用。最近，美國保險(xiǎn)商實(shí)驗(yàn)室 (UL) 批準(zhǔn)了其 UL 60335-2-89 標(biāo)準(zhǔn)的第二版，其中包括更高的 R-290 充電限制，這將擴(kuò)大其在商業(yè)制冷中的潛在用途。

迄今為止，R-290 的 150 克裝料限制阻礙了其更廣泛的應(yīng)用，將其使用范圍縮小到獨(dú)立的冷藏箱或需要使用多個(gè)冷凝裝置以實(shí)現(xiàn)更高的容量。更新后的 UL 標(biāo)準(zhǔn)提高了這些商用獨(dú)立顯示器的充電限制，具體取決于它們是開放式還是封閉式設(shè)計(jì)：

• 開放式電器（無門）的最大充電限制為 500 克。
• 封閉式電器（帶門或抽屜）的最大充電限制為 300 克。

開放式電器的 500 克充電量將限制提高到 R-290 的可燃性下限 (LFL) 的 13 倍，而封閉式電器的 300 克充電限制是 R-290 的 LFL 的 8 倍。

從應(yīng)用設(shè)計(jì)的角度來看，這些更高的充電限制將幫助 OEM 提高系統(tǒng)容量，同時(shí)利用 R-290 的高效率和低 GWP 等級 (GWP=3)。對于尋求滿足可持續(xù)性目標(biāo)或遵守制冷劑法規(guī)的承包商、顧問和最終用戶而言，獨(dú)立的 R-290 箱已成為其整體制冷戰(zhàn)略不可或缺的一部分。

對 UL 60335-2-89 標(biāo)準(zhǔn)的批準(zhǔn)更新是 R-290 在商業(yè)制冷領(lǐng)域更廣泛采用的關(guān)鍵第一步。盡管原始設(shè)備制造商應(yīng)該開始規(guī)劃他們的設(shè)計(jì)周期以實(shí)現(xiàn)這些充電增加，但在更高充電的 R-290 系統(tǒng)可以在美國和加拿大實(shí)施之前，還需要獲得其他監(jiān)管部門的批準(zhǔn)。其他理事機(jī)構(gòu)的待批準(zhǔn)包括：

• 環(huán)境保護(hù)署 (EPA) 的重要新替代品政策 (SNAP) 計(jì)劃；
• 美國采暖、制冷和空調(diào)工程師協(xié)會(huì) (ASHRAE) 15 制冷系統(tǒng)安全標(biāo)準(zhǔn)；
• 即將到來的代碼修訂周期中的模型代碼更新；和
• 州和地方建筑規(guī)范更新。

對于許多美國業(yè)內(nèi)人士來說，R-290 充注限制的增加代表了這種天然制冷劑發(fā)展的合乎邏輯的下一步。甚至在 UL 批準(zhǔn)之前，一些具有可持續(xù)發(fā)展意識(shí)的運(yùn)營商已經(jīng)與當(dāng)?shù)氐慕ㄖ?guī)范管理員合作，實(shí)施 R-290 收費(fèi)較高的系統(tǒng)。此外，自 2019 年以來，歐洲已經(jīng)實(shí)施了 500 克 R-290 充注限制，當(dāng)時(shí)國際電工委員會(huì) (IEC) 根據(jù)其 IEC 60335-2-89 標(biāo)準(zhǔn)批準(zhǔn)了獨(dú)立式商業(yè)展示柜的增加。

經(jīng)過多年的猜測，美國的商業(yè)制冷行業(yè)可以開始計(jì)劃使用 R-290 充注量更大的系統(tǒng)——實(shí)現(xiàn)更高容量的制冷，同時(shí)受益于 R-290 久經(jīng)考驗(yàn)的效率和較低的 GWP 等級。艾默生準(zhǔn)備通過開發(fā)R-290 合格壓縮機(jī)來支持這一轉(zhuǎn)變，這將幫助 OEM 和利益相關(guān)者實(shí)現(xiàn)法規(guī)遵從性、實(shí)現(xiàn)其可持續(xù)發(fā)展目標(biāo)并降低能耗。

For many years, the use of flammable refrigerants — such as the A3 hydrocarbon R-290 (or propane) — has been a keen area of collective focus among the regulatory bodies governing refrigerant safety standards in commercial refrigeration. Offering excellent energy efficiencies and very low- GWP, this natural refrigerant has long been approved for use in applications with a maximum charge limit of 150 grams. Recently, the Underwriters Laboratory (UL) has approved the second edition of its UL 60335-2-89 standard, which includes higher R-290 charge limits that would expand its potential uses in commercial refrigeration.

To date, R-290’s 150-gram charge limit has hindered its wider adoption, narrowing its use to self-contained refrigeration cases or requiring the use of multiple condensing units to achieve higher capacities. The updated UL standard raises the charge limits on these commercial stand-alone displays based on whether they have an open or closed design:

• 500-gram maximum charge limit in open appliances (without doors).
• 300-gram maximum charge limit in closed appliances (with doors or drawers).

The 500-gram charge in open appliances raises the limit to 13 times the lower flammability limit (LFL) of R-290, while the 300-gram charge limit in closed appliances is eight times that of R-290’s LFL.

From an application design perspective, these higher charge limits will help OEMs to increase system capacities while capitalizing on R-290’s high efficiency and low-GWP rating (GWP=3). For contractors, consultants, and end users seeking to meet sustainability objectives or comply with refrigerant regulations, self-contained R-290 cases have become integral to their overall refrigeration strategies.

The approved update to the UL 60335-2-89 standard is a key first step in the path toward wider R-290 adoption in commercial refrigeration. Although OEMs should begin planning their design cycles to enable these charge increases, other regulatory approvals will need to take place before higher-charge R-290 systems can be implemented throughout the U.S. and Canada. Pending approvals by other governing bodies include:

• Environmental Protection Agency’s (EPA) Significant New Alternatives Policy (SNAP) program;
• American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) 15 safety standard for refrigeration systems;
• Model Code updates in the upcoming code revision cycle; and
• State and local building code updates.

For many U.S. industry insiders, the R-290 charge limit increase represents a logical next step in the progression of this natural refrigerant. Even prior to the UL approval, some sustainably minded operators have worked with their local building code administrators to implement systems with higher charges of R-290. In addition, a 500-gram R-290 charge limit has been in place in Europe since 2019, when the International Electrotechnical Commission (IEC) approved the increase under its IEC 60335-2-89 standard for self-contained commercial display cases.

After years of speculation, the commercial refrigeration industry in the U.S. can begin planning for the use of systems with larger charges of R-290 — enabling higher-capacity refrigeration while benefiting from R-290’s proven efficiencies and lower-GWP rating. Emerson is prepared to support this transition by developing R-290 qualified compressors that will help OEMs and stakeholders to achieve regulatory compliance, fulfill their sustainability objectives, and reduce energy consumption.