切勿用一种制冷剂与另一种替代制冷剂一起加注系统,因为不建议混用制冷剂。应使用适当设备回收原制冷剂,并根据美国《清洁空气法案》第 608 条中规定的美国环境保护署 (EPA) 指南进行管理。如果两种制冷剂的安全级别不同,还可能引入新的安全隐患。
行业中常用的不可燃混合物具有 R-410A、MO99 (R-438A)、R-407A、NU22B (R-422B) 等可燃成分,但均被 ASHRAE 认定为不可燃物(1 类)。
来自不同供应商的制冷剂,即使“R 编号”相同,质量也可能不同。对不同供应商的制冷剂进行的随机测试表明,市面上的产品并不总是符合 AHRI 的纯度、成分、水分或空气标准。始终从值得信赖且经验证的供应商处购买制冷剂。
许多 HFO 和 HFO 混合物已广泛用于系统改造和/或新设备。一种制冷剂是可以用于现有系统还是只能用于新设备的决定因素基于安全认证。有几种 HFO 和/或 HFO 混合物具有美国采暖制冷空调工程师协会 (ASRHAE) 1 级(不可燃)认证,已成功用于现场改造和新设备。
虽然像 R-407C 这样的纯氢氟烃 (HFC) 在从 R-22 转换时需要将矿物油全面更换为多元醇酯 (POE) 油,但“矿物油兼容”的替代品已经成功使用了几十年。数十万套 R-22 空调系统已成功改装为使用 Freon™ MO99 (R-438A) 和 Freon™ Nu-22B (R-422B),同时继续使用矿物油。
要了解和比较新的暖通空调与制冷 (HVACR) 系统的效率,您需要考虑设计、部件、使用的制冷剂和运行条件。没有任何单一因素能决定能源消耗。当改造系统并且仅改变制冷剂流体时,可以根据制冷剂本身的特性进行合理的性能比较。然而,当比较用于不同系统设计和/或不同运行条件下的不同流体时,这种比较就不那么重要了。无论是谈论冷却能力、能效等级还是环境影响,总的系统影响决定了结果。“制冷剂及其系统的选择必须基于整体分析,包括能效和性能属性、环境影响、员工和公共安全以及经济考虑。不应根据任何一个单一的因素,如 GWP、工作压力、易燃性等,来选择制冷剂。”
Every equipment manufacturer today makes available specifications for the optimal refrigerant charge. Typically, this involves weighing in charge or measuring superheat and/or subcooling values. Not following the manufacturer's guidelines could lead to a reduction in performance or an increase in callbacks.
https://www.achrnews.com/articles/141371-five-rules-for-charging-refrigeration-systems
R-22 replacements like any product will have a prescribed set of guidelines that technicians must follow. These guidelines are also accompanied by a list or applications or units that the product cannot be used in. When comparing options, there are several points technicians should be aware of such as need for oil change out and replacing critical elastomeric seals.
https://www.freon.com/en/-/media/files/freon/freon-mo99-retrofit-guidelines.pdf
The same best practices and tools used to recover A1 refrigerants such as R-410A and R-404A are used to recover next generation A2L refrigerants such as XL41 (R-454B) and XL20 (R-454C). Technicians should take special consideration to check that their tools, such as vacuum pumps, recovery machines, and recovery tanks are approved for use with products that carry the A2L safety designation. Several manufacturers have already approved models for use, have you checked what’s on your truck?
The Kigali Amendment and associated regulations (AIM Act, F-Gas, ODSHAR) specify a phasedown of HFCs based on CO₂ equivalents. Not a phaseout or manufacturing ban.
https://hvacr.elearn.network/courses/phase-down-vs-phase-out-what-s-the-difference
https://www.epa.gov/system/files/documents/2021-09/hfc-allocation-rule-nprm-fact-sheet-finalrule.pdf
CO₂ systems require components that operate at much higher working pressures, or utilize costly mitigation tactics for high ambient operation.
https://www.coolingpost.com/features-home/heatwaves-and-co2-refrigeration/