R-515A
Binary HFO/HFC near-azeotropic blend — 88% R-1234ze(E) and 12% R-227ea. Honeywell Solstice 515A. ASHRAE A1 (non-flammable — the R-227ea addition pulls the blend to A1 from the pure R-1234ze(E) A2L). GWP 392. R-134a replacement for chillers and commercial refrigeration where A1 classification is required.
Lower toxicity (Occupational Exposure Limit ≥ 400 ppm). No flame propagation in air at standard atmospheric pressure and 60°C. R-134a, R-22, R-410A, R-404A, R-744 (CO2) are A1.
- Flammability
- None (no flame propagation)
- Toxicity
- Lower (OEL ≥ 400 ppm)
Classification per ANSI/ASHRAE Standard 34-2022. See full reference.
Saturation pressure-temperature curve
No PT chart in this build — see manufacturer datasheet. R-515Ahas a published PT chart in its manufacturer's technical datasheet (linked below). The chart has not been transcribed into this site's dataset. For service work, use the manufacturer's published PT chart directly — link below.
- manufacturer-datasheetHoneywell International Inc., Solstice 515A Technical Information / Product Data Sheet.PT chart for R-515A (R-1234ze(E)/R-227ea 88/12 mass% azeotrope-like blend).https://www.honeywell-refrigerants.com/americas/
At a glance
Chemistry
Lubricant compatibility
Near-azeotropic. A1 (non-flammable) — unlike pure R-1234ze(E) which is A2L. R-227ea addition shifts the blend to A1 classification.
Blend composition
- R-1234ze(E)88.0%
- R-227ea12.0%
Trade names
- Solstice 515AHoneywell
Common applications
- Centrifugal chillers
- Medium-temperature commercial refrigeration
- R-134a / R-1234ze retrofit where A1 is required
Properties
- Boiling point (1 atm)-19.0°C / -2.2°F
- Critical point227.8°F at 499 PSIG
- Molar mass119.00 g/mol
- Temperature glideNegligible (0.00°F)
- ODP0
- GWP (AR5, 100-yr)392
- GWP (AR6, 100-yr)416
What is R-515A?
R-515A is engineered to solve a specific service problem: pure R-1234ze(E) has GWP 7 and is well-suited as a long-term R-134a replacement, but it's A2L (mildly flammable). For chiller and commercial refrigeration applications where A2L equipment and procedures aren't available (or aren't acceptable in the regulatory environment), R-1234ze(E) alone isn't a path. R-515A adds 12% R-227ea (heptafluoropropane, a non-flammable A1 HFC with GWP 3220) to the R-1234ze(E) base, raising the blend's overall flammability classification to A1.
The blend is near-azeotropic — temperature glide is effectively zero — making R-515A a true drop-in candidate for R-134a service from a glide-handling standpoint. The pressure envelope is close to R-134a's: at 70°F R-515A saturates at approximately 71-72 PSIG vs R-134a's 71 PSIG. This near-pressure-match means R-515A can be charged into R-134a-designed equipment with minimal compressor adjustment.
The tradeoff vs pure R-1234ze(E): R-515A's GWP of 392 is substantially higher than R-1234ze(E)'s 7 — the R-227ea component (GWP 3220) drives most of R-515A's GWP. R-515A is positioned as an interim solution: lower GWP than R-134a (392 vs 1430), A1 safety class preserved, but not as low GWP as pure R-1234ze(E) alone.
Where R-515A is used
- Centrifugal chillers (R-134a replacement where A1 is required by code or operator preference)
- Medium-temperature commercial refrigeration (R-134a replacement)
- Heat pumps (some commercial applications)
- Service refrigerant for legacy R-134a equipment seeking GWP reduction without flammability classification change
Regulatory & phase-down status
R-515A's GWP of 392 is below the EU F-Gas 750-GWP threshold for chillers but above the 150-GWP threshold for some other applications. Under EPA AIM Act in the US, R-515A is below the 700-GWP threshold for the chiller acceptable-use category — meaning R-515A remains permitted for new chiller installations through current AIM Act schedules.
For very-low-GWP applications (where 150-GWP thresholds apply), R-515B (R-1234ze(E)/R-227ea 91.1/8.9, GWP 287) or pure R-1234ze(E) (GWP 7, A2L) are the appropriate alternatives. R-515A occupies the middle ground — substantial GWP reduction from R-134a, A1 safety preserved, modest performance penalty.
Service notes
POE and PVE oils are compatible. Mineral oil is not used. A1 safety classification simplifies service vs A2L alternatives — no A2L-specific procedures (flame restrictions, ventilation interlocks) are required.
Near-azeotropic behavior (effectively zero glide) means R-515A is handled like a pure refrigerant — single saturation temperature for any given pressure, no bubble/dew distinction needed for superheat or subcooling measurement. EPA Section 608 Universal or appropriate-type certification covers R-515A handling.
Phase-down timeline
No phase-down milestones documented for R-515A in this build. This may mean: (a) no regulatory phase-down currently published; (b) the refrigerant has local regulatory schedules not yet transcribed into the site dataset; or (c) it is a specialty refrigerant outside the main regulatory frameworks. For authoritative current status, consult the EPA AIM Act allocations (40 CFR Part 84), EU F-Gas Regulation 517/2014 + 2024/573, and the relevant national implementations of the Kigali Amendment.
Global warming potential, in context
Medium-pressure centrifugal & screw chillers
Retrofit and replacement paths
R-515A replaces
Frequently asked
›Why mix R-1234ze(E) with R-227ea if R-1234ze(E) alone is lower-GWP?
To get A1 (non-flammable) safety classification. Pure R-1234ze(E) is A2L (mildly flammable) — requires A2L-rated equipment, sealed motors, leak detection, machine-room ventilation provisions. Adding 12% R-227ea (A1, non-flammable) pulls the blend's flammability characteristics below the A2L threshold, achieving A1 classification. The cost is GWP (R-227ea is GWP 3220) — but the blend's overall GWP (392) is still 73% lower than R-134a's. R-515A is the "we accept some GWP for A1 simplicity" point on the design curve.
›Can I retrofit an R-134a chiller directly to R-515A?
Largely yes. R-515A's pressure envelope is within 5% of R-134a's at typical operating conditions. Procedure: recover R-134a; replace filter-drier; pull vacuum to 500 microns; charge R-515A by weight at 90-95% of R-134a nameplate amount (R-515A is slightly less dense liquid). Verify POE oil compatibility (R-134a chillers typically use POE; if some specific OEM used PAG or alkylbenzene, confirm compatibility per Honeywell Solstice 515A documentation). Capacity and efficiency typically within 2-5% of original R-134a performance. R-515A is one of the cleaner "true drop-in" retrofits in the modern refrigerant landscape.
›What is the GWP of R-515A?
392 per IPCC AR5, mass-weighted from R-1234ze(E) (7) at 88% and R-227ea (3220) at 12%. The R-227ea component dominates the GWP — it's only 12% of the blend by mass but contributes ~98% of the GWP. This is the inherent tradeoff: small amounts of high-GWP R-227ea to achieve A1 classification create disproportionate GWP burden.
›What's the difference between R-515A and R-515B?
Both are near-azeotropic R-1234ze(E)/R-227ea blends. R-515A is 88/12 (GWP 392); R-515B is 91.1/8.9 (GWP 287). R-515B has lower GWP because of less R-227ea content. Both are A1; both target R-134a replacement. R-515B is more aggressive on GWP reduction; R-515A has slightly more headroom on the flammability margin. Honeywell offers both as Solstice 515A and Solstice N15 respectively, positioned for different operator GWP-vs-margin preferences.
›Is R-515A subject to phase-down?
Below current chiller-segment thresholds in the US (AIM Act 700-GWP threshold) and EU (F-Gas chiller 750-GWP threshold) — R-515A is permitted for new equipment in those categories. For application categories with lower GWP thresholds (e.g., EU F-Gas 150 for commercial refrigeration), R-515A is not compliant and lower-GWP alternatives (R-515B, R-1234ze(E), R-454C) are required.
›What lubricant does R-515A use?
Polyolester (POE) oil is the primary recommendation. Polyvinyl ether (PVE) oil is also approved by Honeywell. Mineral oil and alkylbenzene are NOT compatible.