# U.S. EPA **March 4, 2014** Nanette Lockwood – Climate Policy **Nanette.lock**

**wo od@irco.com**  (980) 228 - 1532 

# Steve Kujak – Refrigerant Technology **Skujak@trane.com** ( 608) 787 - 3766 

# Bill Hansen – Unitary Product Development (via phone) **Bill.hansen@trane.com** (608) 787 - 2488 

# Ken Schultz – Thermal Systems **Kschultz@trane.com** (608 ) 787 - 3735

# Refrigerant Flammability **and the Standards**  Steve Kujak IR Refrigerants Technology Leader**3** 

# Recap **- What is Flammable?** 

Measurement of burning velocity and heat of combustion do not indicate the risk and severity of an event**4** 

# Relative Flammability **Examples**

Some Class 2 refrigerants can look like Class 3’ s

Noticeable dif

ferences in 2L ’s **Class 3 Propane**  **Class 2 R152a** 

**Class 2L <10 to 6.7 cm/sec**  **R143a R32**  **Am monia**  

### Class 2L **<5 cm/sec 60%**  **R32/40% R134a**  Propane pool 120 grams R152a 300 grams Pool R152a bunsen burner

R143a bunsen burner R32 1000 gram

Pool 70_30 R32R134a Bunsen Burner Pool 60_40 Blend

R32R134a Pilot**5** 

# Recap **- Preventing Ignition**  **Events**

Simulations show flammable mixtures are possible in occupied spaces with a potential for ignition events **Concentration betw**  **een LFL**  **- UFL** 
**Ignition Source Air V**  **elocity less than**  **Burning V**

**elocity** 

# Ignition **Event** Controls
• Restrict charge s ize • Redesign system to put charge outside • Detection & ventilation

Controls
• Can o nly control within equipment • Control ignition sources outside equipment ($$$$) • A llow only high MIE’s (minimum ignition energy) refrigerants Controls Tu rn on fan (not realistic from a power use and equip storage standpoint) Could feed the flames! (Strong to weak) 1. Flames 2. Electrical 3. Hot surfaces**6** 

# Standards **- Flammability**  **Focus**

Safety standards developing on multiple fronts • Restrict charge s ize • Redesign system to put charge outside • Detection & ventilation

• Put sources/refrigerant within equipment • Control ignition sources outside equipment ($$$$) • A llow only high MIE’s (minimum ignition energy) refrigerants Putting controls in place within and some controls for outside equipment; 1. Flames 2. Electrical 3. Hot surfaces 

## Controlling **Concentration betw**  **een LFL**  **and UFL**
**Controlling Ignition Sources**  

# Ignition **Event 7**  **R1234ze = no**  **ignition at room temp, No BV**  **R1234y f = 5,000**  **mj (BV =**  **1.5 cm/sec)**  **) R717**  **~<100 mj**  **(BV=7.2 cm/sec) R32 ~<30**  **mj (BV = 6.7 cm/sec)**  **R446A ~<10**  **mj (BV =**  **9.0 cm/sec**  **) R152a**  **~<0.38 mj**  **(BV = 23**  **cm/sec) R290**  **~<0.25 mj**  **(BV = 40**  **cm/sec )**  

# Recap **- Minimum Ignition**  **Source Strength Comparison**  **AS HRA**  **E proposal**  •  **5 cm/sec 2L**  **limit** • **B ased on**  **AS HRAE**  **1584 w ork**  • **Eliminates human static**  **discharge possibility**  • **I gnition**  **source u**  **p to 100 mj** 

• **Status: Vo**  **ted to further review**  **Burning V**

**elocity vs. Minimum**  **Ignition Energy**  **( MIE)**  **AS HRAE**  **TRP -**  **1584**

**Flammable Region**  **Non -**  **Flammable Region**  100x change in MIE

over 7 cm/s range



### Proposed 2L **Limit**  **5 cm/sec** Human static discharge


## Not all current ASHRAE 2Ls are likely to remain 2L Class 3 Class 2 Class 2L, BV 10 to 5 cm/sec Class 2L, BV <5 cm/sec

# Bill Hansen Director Unitary New Product Development 

# Managing Flammability in the Standards**9** 

# UL 484 Products are Installed **in Existing Homes and Businesses Window**  **a nd Floor Mounted Products have the**  **G reatest**  **Risk for Flammability** 

- **Room Air** 

**- Conditioners** 

- **Portables**

- **PT AC’s (largest**  **charges typically)** 

# Common Ignition **Sources cannot be regulated 1.**  **Flames 2.**  **Electrical 3.**  **Hot surfaces**



## UL 484 Can Only Regulate the Product, NOT the Application Consumer Purchase and Applied**10** 

# Charge Size Methodology **and Application Limits**

**C harges**  **s izes** 

- **These products are historically**  **hermetic products**  **with small**  **refrigerant charges** 

- **Used Equiv**

**. 1.0 lbm** 

**/ton R410A**  

## Cooling loads by application **type Highest**  **demand to**  **lowest (ft**  **2 /ton**  **cooling) 1.**  **Commercial Kitchen**  **- 93**  **2. Restaurant**  **– 187**  **3. Retail**  **– 393**  **4. Residential**  **– 850** 



## Leak rate **scenarios**

- **Fast Leak –**  **25% /min**  

## Flow Model

- **Quadratic –**  **Inherent flammable**  **flow region**  

## Application **Height**

- **C an lead to unsafe situations** **11** 

# Charge Size Methodology **– Equation** 

Flammability equation has some gaps for safety and does not apply to all

product application situations .

**Charge calculation heav**  **ily d**  **ependent on;** 

**- LFL**  **of refrigerant** 

**- Charge**  **per ton capacity**  **v aries** 

**- Ap**  **plication height** 

**- Building**  **cooling load**  **demand**

**- Safety**  **f actor**  **constant of**  **2.5** 

### AL **( Ap**  **pl ic**  **at io**  **n Li**  **mi t)**  **= A**  **mi n**  

### (m **2** 

### )/ **Ca p**  **clg** 

### (m **2** 

### ) **= 1.**  **0** or **A min**  

### (m **2** 

### ) **- Ca**  **p clg**  

### (m **2** 

### ) **= 0**  Whe re : 

### A **min =**  **(M/(2.5*(LF** **L) 5/4**  ***h 0**  **)) 2**  **= (m**  **2 )** 

 **M –**  **mas s**  **of t**  **he l**  **arge st**  **re fr**  **ig er**  **an t**  **syste m**  **(k g)** 

 **LF L**  **– lo**  **we r**  **fla mmabi**  **lit y**  **lim it**  **( kg/m3**  **)**

 **h 0**  **– point**  **o f**  **re lea**  **se o**  **f le**  **ake d**  **re fr**  **ig er**  **an t**  **(m )**  o **Ceilin g**  **mounte d**  **– 2.**  **2m** o **Wa ll**  **mounte d**  **– 1.**  **8m** o **Wi ndow**  **mounte d**  **– 1.**  **0m** o **Flo or**  **mounte d**  **– 0.**  **6m Ca**  **p cl**  **g = M**  **/m'** ***** **A c**  **= (m**  **2 )** 

 **M –**  **mas s**  **of t**  **he l**  **arge st**  **re fr**  **ig er**  **an t**  **syste m**  **(k g)** 

 **m' –**  **mass re**  **fr ig**  **er an**  **t/coo lin**  **g cap**  **aci ty (**  **kg/kW )** 

 **A c**  **– Ar**  **ea coo**  **led/ kw**  **cool ing**  **capaci ty**  **(m 2**  **/kW )** 


### • **AL -**  **When the area that can be cooled is less than the area required for safety there is a high risk of**  **mis -**  **application** • **Floor Mounted, Commercial Kitchens is worst case.** 

## • **Can only be controlled by charge limits** **12** 

# Class 3 **– Max Charge**  **Size**

Current EP

A Rule 17 safe level for Class 3 Limits flammability risks

**Class 3 Ap**  **plication Limits (kg)** 
• Floor < 57g (0.016) • Window < 57g (0.045) • Wa ll 0.145 • Ceiling 0.217 ***UL 484 1 Kg limit**  **unjustified** ***UL484 limit should**  **based on household**  **refrigerators (UL250)** 

**Initial Proposed UL Limit**  **- 1 kg**  **“Limit unsafe” R290 ~<0.25**  **mj (BV =**  **40 cm/sec**  **) 13**  

# Class 2 **- Max Charge**  **Sizes R**  **- 152a**  **Ap plication**  **Limits (kg)** 
• Floor 0.132 • Window 0.378 • Wa ll 1.19 • Ceiling 1.78 ***Limits ~4x to 8x higher than**  **Class 3 based on LFL ’s**  **being higher**  **.** ***Class 2 MIE’ s**  **and BV’ s v**  **ery similar**  **to hy drocarbons.**  **Should they**  **b e treated like Class 3?** 

**R152a ~<0.38**  **mj (BV = 23 cm/sec**  **) R290 ~<0.25**  **mj (BV =**  **40 cm/sec**  **)** 

## Current EP

A Rule 17 safe level for all Class 2 at this point Limits flammability risks **Initial Proposed UL Limit**  **2.8 kg R152a 8 kg R32**  **“Limits Unsafe” 14**  

# Class 2L’s Charge **Sizes Safety**  **M ethodology**  **Breaks Down**

LFL and BV appear insuf ficient to set 2L

charge limits Industry working to resolve ***Charge limits 3**  **x -**  **19x more than Class 2**  **R152a.** ***** **R1234y f less**  **safe than R -**  **32?** ***R1234ze wo**  **uld be less safe**  **than R32 as w**  **ell? Does**  **that make sense?** ***Should a max charge limit be set for this 2L**  **category ?**  ***Should a new f**  **lammability class**  **be developed?**

**Floor Win**  **dow Wa**  **ll Ce**  **ilin g**  Ar ea - m 2 0. 4 1. 1 3. 7 5. 5 Charge - k g 0. 016 0. 045 0. 145 0. 217 Ar ea - m 2 1. 9 5. 4 17. 5 26. 1 Charge - k g 0. 132 0. 37 1. 2 1. 8 Ar ea - m 2 8 22 71 106 Charge - k g 0. 41 1. 1 3. 7 5. 5 Ar ea - m 2 52 145 471 704 Charge - k g 2. 5 6. 9 22. 2 33. 2 Ar ea - m 2 22 61 197 295 Charge - k g 1. 5 4. 2 13. 5 20. 1 Note 1 - Th e v al ue is th e % ch arge ( lb m/ton) req ui red f or t he ref ri ge ra nt rela ti ve to R410a . **R1234y f**  **R446A** 40 0. 25

6. 7 30 0. 156 **Appl ic**  **ati on Li**  **mi ts**  **R290**

**R32 R152a**  **Area /**  **Char ge**  **Eq uiv**  **R410a 1**  75% 130% 100% **Ref ri**  **g Class**  **BV cm/**  **s MIE**  **<Mj LF**  **L kg/**  **m 3** 

0. 306 0. 290 130% **A3 A2**  **A2 L**  **A2 L**  **A2 L**  1. 5 5000 90% 23 0. 38 9 10 0. 038

0. 110



### Current Committee Discussions**15** 

# Conclusions

• **We do not recommend adopting UL 484 until it is completely rev ised** 

- **Class 3 w ill hav**  **e << 1**  **K g charge**  **limits**  Industry believes 1 Kg creates unsafe conditions for highly flammable refrigerants  ISO 5149 includes 1kg and higher charge limits

- C ompetitive pressures and not justified through science

- Adoption potential will be driven by competitor interests and local pressures

- **Class 2 w ill also**  **hav e**  **low er charge limits** 

- **Timing**
 Meeting at UL Northbrook Mar 4 th to continue to revise draft  Target complete draft June 2014  Review complete 4Q14  Implementation early 2015

- **No 2L updates in this rev**  **ision**
 Expect 2L UL revisions to follow IEC 2 - 40 acceptance (2017) 

### • **UL484 charge limits should**  **not substantially exceed EPA R**  **ule 17 charge limits for Class 2 & 3 refrigerants** 

- **The science supports a charge limit restriction “on the small side” for self contained products w**  **ith flammable refrigerants** 

# Low GWP Replacements for R410A & R22
Ke n Schultz, PhD St aff Thermal S yste ms Engineer**17** 

# The Transition **Away from R22**   

# Came **down to three alternatives**  **globally...** o Early adoption in Europe = 

# R404A o Near drop - in replacement = 

# R407C o Higher pressure/capacity = 

# R410A

**And the wi**  **nner is ... R410A.**  modeled conditions approximate AHRI Std - 210/240 Condition A Tevap = 50 ° F Tcond = 115 ° F**18** 

# Transition **Away from R410A** 
 

## Primary constituents **in blends** o R32 GWP = 675 class = A2L o R1234yf 4 A2L o R1234ze 6 A2L 

###  

## Secondary constituents **in blends** o R125, R134a, R152a, CO 2 **The new “HFO’ s”**  **. “Mildly**  **” flammable.**



## Lacking non **- flammable**  **low G**  **WP blend materials**  **(R -**  **125 -**  **like). Industry**  **needs to find more high pressure chemistries.**  **Will McLinden**  **and Domanski**  **find any thing?**  

# What’s in the toolbox?

o **NO very low GWP (<150) r**  **efriger ant**  **molecules with**  **pr essur**  **es compar**  **able to R410A or**  **R22 (that aren’t**  **A3’ s)**  **.** 

### o **R32 needed to**  **ke ep**  **pr essur**  **es (**  **ie ,**  **capacities) in the r**  **ang e**  **of R410A or R22.** **19** 

# Transition **Away from R410A**   

# R32 **and blends proposed under AHRI Low GWP**  **AREP I ...**

**And the wi**  **nner wi**  **ll be ... ???.**  **No	A1’s!** 

##  

# R410A  

# R22/R407C**20** 

# R410A/R22 **Alt’s Tested**  **by Trane**
 **R410A -**  **like blends have GWPs of ~500.**  **A1 1295**  **A2L 206**  **A2L 407**  **A2L 979**  **A1 1577**  **A2L 482**  **A2L 331**  **A2L 494**  **A2L 494**  **A2L 246**  **A2L 296**  **A2L 490**  **A2L 675**  **A1 2088**   **R22 -**  **like blends have GWPs as**  **low as 200 -**  **250.**



## A **range of options. A**  **range of trade -**  **off ’s**  **. 21**  

# Best R410A **Alt’s –**  **Capacity & COP** 

 

## R32 **(GWP = 675)** o CAP and COP increased, but not as much as predicted. 

###  

## DR5 **(GWP = 490)** o Very similar performance to R410A; potential near drop - in 

###  

## L41’s **(GWP = 494)** o Small reductions in capacity; maybe okay? 

###  

## DR4 **(296)** 

## , **ARM70a (482)**  o Performed better than expected – interesting?**m e** **a s** **u r** **e d** **r e** **s u** **l t** **s s** **i m** **p l** **e m** **o d** **e l** **m e** **a s** **u r** **e d** **r e** **s u** **l t** **s s** **i m** **p l** **e m** **o d** **e l** **c a** **p a** **c i** **t y** **e f** **f i** **c i** **e n** **c y**  

## Need also to consider **discharge temp’**  **s, glide,**  **HXer performance,**  **... 22**  

# Best R22 **Alt’s –**  **Capacity & COP** 

 

## L20 **(A2L, GWP = 330)** 

### o Matched predictions. Close match to R22 capacity; need to make up for lower efficiency.  

## LTR4X **(A1, GWP = 1300)** 

### o Matches R22 capacity, but efficiency is down. A1 but “high” GWP (~1300).  

## DR7 **(A2L, 245)**  

## , ARM32a **(A1, 1575)**  

### o A little extra capacity, but efficiency is down ~10%.**m e** **a s** **u r** **e d** **r e** **s u** **l t** **s s** **i m** **p l** **e m** **o d** **e l** **m e** **a s** **u r** **e d** **r e** **s u** **l t** **s s** **i m** **p l** **e m** **o d** **e l** **c a** **p a** **c i** **t y** **e f** **f i** **c i** **e n** **c y**  

## Need also to consider **discharge temp’**  **s, glide,**  **HXer performance,**  **... 23**  

# Compressor Discharge **Temperature**

**Excessive discharge temperature**  **creates reliability**  **problems wi**  **thout mitigation**  **(e.g., liquid**  **or gas injection) Mitigation**  **technologies impact performance**  **R22 alterna tiv**  **es R410A**  **alterna tiv**  **es R32 is**  **wor st**  **off ender!** 
**Industry Limit** **24** 

##  

# Glide generally increases as move from R410A **- like blends**  **toward R22 -**  **like blends.**  o Capacity is generally decreasing in this direction.  o GWP is generally decreasing in this direction.  o Potential efficiency tends to increase in this direction.  

# Temperature **Glide in**  **Zeotropic Blends** 

**An ideal candidate has <2F of glide**  **L arge**  **glides because these blends contain CO**  **2 .** **25** 

# Comparison **of Lower GWP Alternatives**
**†**  **reference** 

## R410A **R32 DR5**  **L41’ s**  **.... DR7**  **L20 R22**  **CAP 1.00†**  **+12% +1%**  **- 5%**  

# ? **- 25%**  **- 28%**  **- 29%**  

## COP **1.00† +4%**  **+3% +4%**  

# ? **+2% +9%**  **+11% ∆**  **Td chr**  **g (**  **° Fd**  **) 0†**  **+40 +15**  **+20 ?**  **– 10**  **+10 +5**  

## Glide ( **° Fd**  **) ~0**  **0 2**  **~5** 

# ? **~8 ~11**  **0** 

## Hi **Ta mb**  **50C CAP**  **/COP 1.00** 

**1.00 +7%** 

**+6% +6%** 

**+5% +4%** 

**+3%** 

# ? **+1%**

**+0% +7%**  **+6% +8%**  **+8%** 

## GWP **2088 675**  **490 494**  

# ? **246 331**  **1810 Flam**  **BV (cm/ s)**  **A1 A2L**  **~7 A2L** 

**~4 A2L**  **~4 or**  **~9** 

# ? **A2L**

**<3 A2L**  **6 -**  **7 A1**  

## Ther **e ar e no ideal r**  **eplacements f or R410A**  **or R22. Wha**  **t will mak e the best compr**  **omise? DR5?** **26** 

##  

# “Toolbox” for R410A/R22 replacements is limited: o Blends of R32, R1234yf, and R1234ze with a sprinkling of others. o R410A - like alternates are at best “2L”. o R22 - like alternates can be lowest GWP ( 330 .. 250). 

##  

# Large number of competing/opposing factors: o thermodynamics

~ operating pressure = capacity

~ inherent efficiency

~ blends = temperature glide 

## o range of operation  reliability

~ high ambient temperatures

~ compressor discharge temperatures 

## o safety and environment  flammability and GWP 

# Conclusions

**CAP COP**  **GWP glide**  

# re **lationship trends**

**Low er**  **GWP R410A** 

**& R -**  **22 alternatives possible,**  **how ever**  **, wi**  **th more compromises**  **than today**  **.**

# R410A & R22 Refrigerant Choices for High **Ambient Temperatures** Ke n Schultz, PhD St aff Thermal S yste ms Engineer**28** 

# R22 **to R410A Transition**   

# Did we give **away performance**  **at high ambient**  **temperatures? Wa**  **lid Chakroun**  **, Kuwait University “Challenges For High Ambient T**  **emperature Countries” Seminar 18 @ ASHRAE/NY**  **C Jan -**  **2014**

70 80 90 100 110

**CA AZ**  **NV UT**  **TX CO**  **FL MO**  **VA NY**  **WI** 

## US 1% Cooling DB ( **° F)** 

**In man y loca**  **tions, the design cooling**  **loads occur a t**  **temper at**  **ur es well**  **abov e**  **typical r at**  **ing conditions**  **( 95**  **° F/**  **35 °**  **C) Saudi Ar**  **abia 1% DB: 86.5**  **° F .. 111.5**  **° F**  **Kuwait max Ta**  **mb = 52**  **° C**  **= 126 °**  **F 40.. 46.3**  **° C**  **104..115 °**  **F India 1% Cooling DB:**  **91 °**  **F .. 109 °**  **F 29**  

# Performance **- R410A**  **Alternatives R410A**  **alterna tiv**  **es along with R22 f**  **or r eference (modeled)** 

**R -**  **22 perf**  **ormance best a t high ambients, but R410A**  **and pr oposed**  **alterna tiv**  **es ar e within**  **10%. 30**  

# Performance **- R**  **- 22**  **Alternatives**

**R -**  **22 perf**  **ormance best a t high ambients.**  **L -**  **20 looks lik**  **e a g ood**  **ma tc**  **h but**  **has high glide. R22 alterna**  **tiv es along with R410A**  **fo r r**  **eference (modeled) 31**  

# Comparison **of Test & Field Experiences** 

**Measur ed: K**  **oolman air -**  **cooled w ate**  **r chiller (~4.5 RT)**

**Out test data is consistent with tr**  **ends r eported r**  **ecently by Chakr**  **oun at**  **ASHRAE/NY Conf er**  **ence (Jan -**  **2014). 32**  

##  

# R410A a good **replacement for R22 in high ambients** o Loss of capacity (<10%) is manageable. o Recently reported high ambient field experiences from Middle East validates R410A performance acceptable compared to R - 22. 

##  

# Lower **GWP alternative performance no worse than R410A** o Concerns/compromises

~ Compressor discharge temperatures a concern with most candidates.

~ Glide is also a concern with some R410A and with all R - 22 candidates.

~ Safety – Some candidates have high burning velocities. 

# Conclusions

**Lower GWP alterna tiv**  **es to R410A are**  **possible, but**  **ther e ar**  **e mor e compr**  **omises.**