VcV (Variable Choke Venturi) Emissions Reduction System Update and Cord Wood Testing Commentary Prepared By: Myren Consulting, Inc. 4/16 for presentation at the Green Heat Alliance’s Pellet Stove Design Challenge

DISCONNECTS Section (5) “…The burn rate for the low burn rate category must be no greater than the rate that an operator can achieve in home use …” Does this mean that a home owner must be able to achieve the same low burn rate at the same setting? Industry Regulatory Community “Wood Stove Lab Rats” speak a very specialized, highly technical language which can be very easy to misconstrue/ misunderstand

What is the VcV System? VcV’s are simple mechanical devices that operate using the static pressure in the stack 2 VcV’s / stove, possibly 3 Primary VcV – operates mainly on “Low”. “Foolproof” 2nd VcV – operates over the entire burn rate range Each operates differently but all work together to synergistically to reduce emissions and increase %OE. 3 rd LPAO VcV will focus on the difference in the way hard wood and soft wood burn

PRIMARY SECONDARY LPAO VcV’S

STATUS VcV’s - under development since 2008 Initial focus was with crib fuel Recent focus has been with cord wood ECOVISION submitted a formal request to EPA on 10/13/15 to conduct a certification test series with cordwood using the ASTM draft cordwood test method and 4” (110 mm) filters ECOVISION received EPA’s approval on 1/4/16 Back and forth exchange to clarify testing issues – is ongoing Are now moving forward towards testing EPA Certification Testing anticipated to take place in May/ June 2016

EPA’s APPROVAL CONTAINED 5 ADDITIONAL REQUIREMENTS FOR EPA M28R Filter Temperature to be Maintained Between F Use of (Glass) Cyclones Filters weighed in pairs Filters – Pall TX-40 TFE coated glass fiber filters or equivalent Only 1 point outside ± 10% proportionality range per test

I think the language in Point 2 needs to be revised. Point 2 reads: “A glass cyclone must be used between the sampling probe and filter holders when the total particulate catch is expected to exceed 100 mg or when water droplets are present in the stack gas. This cyclone and its components must be included in the pre-test weighing and post-test desiccation and weighing.” My proposed revision is: “A glass cyclone must be used between the sampling probe and filter holders when the total particulate catch is expected to exceed 100 mg or when water droplets are present in the stack gas or when water droplets condense in the sample probe, the cyclone and its associated glassware or in the filter housing. The catch in the cyclone and its component glass ware must be included in the total catch via an acetone wash process, desiccation and weighing like what is done with the sample probe and filter housing components.”

EPA’s APPROVAL CONTAINED 5 ADDITIONAL REQUIREMENTS FOR ASTM DRAFT CORDWOOD TEST METHOD Wood Heater to be aged for 50 h (vs. 48 h) End of Test Criteria – when all the test fuel charge has been burnt. Same as EPA M28 and M28R Wood Heater Avg. Surface (Delta T) and Stack Temps within 10 F of ambient (vs. within 40 test start Invalid Test Run - if <100% of test fuel charge is burnt “Level” test start

END OF TEST CRITERIA REVISION As presently written one is required to end all tests after 100% of the test fuel weight has been consumed. This would make it impossible to start a Medium or Low burn test after a High burn test because there would not be enough coals left in the stove to meet the minimum coal bed weight requirement for the start of a Medium or Low burn test. And there is no alternative direction provided for how to establish a coal bed for the Medium or Low burn tests.

END OF TEST REVISION (CONT.) One way to resolve this issue would be to stop the high burn test as per the criteria in the ASTM draft, i.e., when 90% of the high burn fuel load weight has been consumed, which would provide the necessary coal beds for the Medium and Low burn tests. And then stop the Medium and Low burn tests when 100% of the test fuel load weight has been consumed. Valid Medium and Low burn tests would have to burn 100% of the test fuel load weight.

CYCLONE GLASS WARE (L)

WHY CYCLONES?

New Equipment Required for Cyclones 1. Assembly Stand, 2. Carrying Bracket, 3. Test Stand While Cyclones are commonly used during stack testing, their use in wood heater testing requires that special equipment be used to insure that each filter set can pass a pre and post test leak check because all 4 of the joints must be held in position.

PREHEATING FILTERS BEFORE TEST START

EACH HEAT LAMP HAS ITS OWN DIMMER SWITCH TO VARY HEAT OUTPUT

HEATED FILTER SET IN USE

ROOM BLANK

VALVE TREE

PM SAMPLE REQUIRED FROM FOLLOWING TEST SEGMENTS TRAIN 1 TRAIN 2 Kindling/ Start-Up Kindling/ Start-up High Burn 0-60 min High Burn High Burn 60+ Low Burn 0-60 min Low Burn Low Burn 60+ TRAIN 3 (ROOM BLANK) High Low

OVERKILL ? 10 Filter Sets, 8 with Cyclones, for a High followed by a Medium or Low Test, all of which have to be ready to go at the start of the High burn test.

POINT OF THE SPEAR SUGGESTIONS TO IMPROVE ASTM E2515 AND THE FRM CORDWOOD TEST METHOD Eliminate dual trains for 4” filters Eliminate filter set change at 60 minutes Increase sample catch Change Pitot Tube Leak Check Procedures Change Constant Weight Criteria

Eliminate Dual Train Requirement for 4” Filters Original NSPS did not require dual trains for the 4” filters used in EPA M5G-1 Original NSPS did require dual trains for the 47mm filters used in M5G-3 due to low sample flows (<0.25 cfm) and low sample catches Originally ASTM E2515 only allowed the use of 47mm filters, so the dual trains made sense. With the new NSPS allowing the use of 4” filters the dual train requirement makes no sense and is really overkill

Eliminate Filter Set 60 Minutes Condar Sampler – History/ Knowledge base Been doing this for about a year now and what have we learned? Other than lab personnel, is anyone looking at this data? 1 hour standard (?) Filter Photos If there is substantial catch on the 60+ filter, the unit has failed! You can’t get emissions under 2.0 (or 2.5) g/ h with a substantial catch on the 60+ filter

Increase Sample Catch Increase Sample Flow Rate from ~0.5 to 1.0 (or more) cfm. Have to stay below filter face velocity limit of 30 ft/ min. (See EPA M5G Section 7.2.1) Decrease Tunnel Flow Rate from ~140 dscfm to something considerably less than 140 dscfm Increasing PM sample catch will increase the accuracy of test results. (Paul Tiegs also advocated doing this.) Jeopardy 1. Increasing the sample flow rate may increase the filter temperature slightly 2. Decreasing the tunnel flow rate will definitely increase the filter temperature and the moisture content of the PM sample gas 3. Have to work with this and see what is possible. Don’t want to trade 1 problem for another!

Constant Weight Criteria Constant Weight Criteria in original NSPS was ± 0.5 mg for both 4” (110 mm) and 47 mm filters, probes and beakers ASTM E2515 which only allowed the use of 47 mm filters decreased the constant weight criteria to ± 0.2 mg Analytical balances have a resolution of ± 0.1 mg so the ± 0.2 mg constant weight criteria is just ± 0.1 mg above the resolution capability of an analytical balance This issue is compounded by the fact that “Scale Rooms” have to have a %RH that is <50%, which increases the problems with static electricity – and thus with meeting any constant weight criteria. So now that we are able to use 4” filters with their increased sample catch, returning to a constant weight criteria of ± 0.5 mg makes sense, especially if we were to increase the sample catches

SCALE ROOM “GROUNDING”

PITOT TUBE LEAK CHECK CRITERIA Typical pitot reading in my lab is 0.04” H2O (.045” for High) for a tunnel flow rate of 140 dscfm Pitot reading determines tunnel flow (Qsd) which in turn determines g/h, so the accurate resolution of pitot readings is critical. Pitot Leak Checks have to be done at ± 3.0” H2O. (EPA M2 Section 2.1) This is a carryover from industrial stack testing. This requirement limits the manometers that can be used Dwyer Model has a 20” 0-2.0” inclined scale and a 2-10” vertical scale. The 20” 0-2.0” inclined scale has a scale resolution of 0.5 linear inch/ 0.5” H2O. This is the best resolution possible if just 1 manometer is used. The resolution on other manometers is much less. Dwyer Model 215 has an inclined scale of ” with scaling of 1.0 linear inch/ 0.05” H20. Much better resolution.

Dwyer Model ” Manometer

Dwyer Model ” Manometer

HIGH BURN ISSUES Once of the issues raised in the comments submitted in the last round of balloting was how to fairly determine a “weighted average emission rate”. As we start down that path let us remember that according to Dr. Jim Houck only about 1/3 of all fires are actually cold high burn starts. Thus with the way the emission rate is calculated in the present draft, industry is taking a “hit” because the calculations assume that every test is a cold start.

TEST START ISSUES 1 OF THE THINGS THAT AFFECTS (1.) STOVE PERFORMANCE AND (2.) ACHIEVING A LOW BURN (≤ I.O KG/H) IS THE AMOUNT OF CHARCOAL VS. THE AMOUNT OF SOLID FUEL IN THE COAL BED WHEN EITHER THE HIGH OR LOW BURN TEST FUEL CHARGE IS LOADED. IF THERE IS A LOT OF SOLID FUEL IT IS MUCH HARDER TO MAKE LOW SIMPLY BECAUSE THE SOLID FUEL BURNS UP QUICKER THAN CHARCOAL. IT WOULD BE VERY INTERESTING TO START A HIGH AND LOW ON A M28 TYPE COAL BED AND SEE WHAT HAPPENS

SUGGESTIONS Get the momentum for changing to a cord wood test method and certification process underway (again) by offering incentives to those who would test and certify with cord wood – Cord wood certificates good for 10 years after the new cordwood FRM is promulgated –Stoves certified with cord wood get preferential treatment in Change Outs and in SIPS Do a field study with ~5 different cord wood certified stoves ASAP for an “immediate” feed back loop. Are the stoves working as anticipated? If not, what needs to be changed in the test method to correct the problem(s).

CONCLUSIONS WE ALL NEED TO WORK TOGETHER ON THE DEVELOPMENT OF THE NEW CORD WOOD FRM TEST METHOD THIS MEANS SOME FOLKS IN THE REGULATORY COMMUNITY WILL NEED TO SPEND SOME SERIOUS TIME IN A LAB WATCHING AND HELPING DO CORD WOOD TESTS - ACTUALLY DOING “X”. IN SHORT, BECOME A REAL “WOOD STOVE LAB RAT”! WE NEED TO ELIMINATE THE “DISCONNECT”!

Thank You! BNL Sponsors Attendees Gauld Family from NZ

Answer to Question About Section (5) Static Pressure - Because a home owner is using a “real world” chimney that vents directly into the atmosphere, as opposed to a “Freely Communicated” lab chimney which vents inside the lab, the static pressure will be higher, sometimes much higher, in the “real world” chimney. At the end of the Colville Demonstration Project we ran an EPA M28 crib fuel test using a “real world” chimney on the same stove that we had previously run a “Freely Communicated” M28 crib test in and the DBR increased from 1.03 to 1.30 kg/h. Both tests were run at the Low Burn Stop.