Report on Testing of the Econoburn Model EBW Wood Hydronic Heater using Partial Thermal Storage

Transcription

1 Report on Testing of the Econoburn Model EBW2-17 Wood Hydronic Heater using Partial Thermal Storage Brookhaven National Laboratory T. Butcher, R. Trojanowski, C. Brown, G. Wei June 13 th, 214

2 ABSTRACT This report presents results of efficiency and air pollutant emissions tests of a modern, cordwood-fired, two-stage, gasification, hydronic heater developed in the Northeast. With a nominal heat output of 17, Btu/hr, the test unit would be suitable for use in a residential application. The unit requires thermal storage, and was tested with a nominal 4-gallon water storage tank. Although this unit has the capability of modulating its firing rate, using it without storage has the potential for extended operation in a high-emission slumber mode and possibly shutdown by the temperature safety control. The unit was tested according to the Partial Thermal Storage Test Method, which was recently proposed by Brookhaven National Laboratory (BNL PTS method). This procedure was developed as a modification of the U.S. Environmental Protection Agency Method 28 WHH, which applies to units that do not require thermal storage. Testing was conducted under nominal full load as well as under a load of less than 15% of the nominal full load, Category IV and Category I respectively. The results of these tests were used to determine annual average values of efficiency and particulate emissions with the procedures in the BNL PTS method. In addition, particulate emission rates and carbon monoxide emission rates were determined for the startup, steady state, and end phases. The annual average for particulate emission was found to be.16 lb/mmbtu of energy output. Annual average thermal efficiency was found to be 6.2%. The average particulate emission rate was found to be 2.7 grams/hour. i

3 Contents Experimental... 1 Test Method... 1 Boiler Description... 1 Installation Overview... 4 Dilution Tunnel... 5 PM Measurements... 5 Flue Gas Analysis... 6 Fuel Type and Loading... 6 Wood Moisture Measurements... 7 Temperature Measurements... 8 Analysis of Efficiency... 9 Phases of the Burn Period... 1 Results Category IV Category I... 2 Summary... 3 Abbreviations AHRI Air-Conditioning, Heating, and Refrigeration Institute ASTM American Society for Testing and Materials BNL PTS Brookhaven National Laboratory Partial Thermal Storage (test method) cfm cubic feet per minute CO carbon monoxide CSA Canadian Standards Association ESF SUNY College of Environmental Science and Forestry ID Induced Draft (refers to a boiler fan located at the exhaust as opposed to a fan which pushes air into the combustion chamber (forced draft)) MMBtu million Btu (British Thermal Unit) NDIR Non-dispersive infrared (gas analyzer) NIST National Institute of Standards and Technology NYSERDA New York State Energy Research and Development Authority PM Particulate Matter SLM Stack Loss Method (for efficiency determination) WHH Wood Hydronic Heater ii

4 Experimental Test Method The tests presented in this report were guided by BNL PTS Method. As allowed by this method, tests in Categories II and III were not conducted because of good performance in Categories I and IV. The burn rate categories specified by this method are summarized in Table 1. Table 1:Burn Rate Categories of BNL PTS Method Category I Category II Category III Category IV < 15%* 16 to 24%* 25 to 5%* Maximum burn rate * Percentage based on nominal rating Boiler Description The unit tested is the Model EBW2-17 hydronic heater, manufactured by Econoburn boilers LLC. This unit is a two-stage, downdraft gasification unit with a nominal heat output of 17, Btu/hr. The heater incorporates an oxygen sensor and variable speed induced draft fan with a fully automatic control system. This unit is intended for installation either indoors or outdoors if a factory-installed weather proof jacket kit is used. As-tested the unit was configured without the weather proof jacket kit. This unit is intended for use with cord wood fuel only. Figure 1 provides an illustration and Figure 2 a photo of the unit. 1

5 Figure 1 Illustration of the hydronic heater tested 2

6 Figure 2 Photo of unit tested 3

7 Installation Overview Figure 3 illustrates the hydronic piping system of the boiler as installed at BNL. The system includes two storage tanks; each tank has a nominal volume of 4 gallons. The actual tank volume is gallons. Each tank is also equipped with a plate type heat exchanger for rejecting heat from the system, and a commercial thermopile 2 for determination of heat output. Figure 3: Test arrangement in BNL lab All piping and the storage tanks are well-insulated. With this system configuration, the boiler can deliver heat to one or two of the tanks and/or the heat exchanger. In addition, the boiler can be isolated from the storage tanks and heat from the tanks can be rejected to the heat exchanger. Note, for this test only one storage tank was used. 2 Delta-T Corporation, 4

8 Dilution Tunnel The boiler vents into a dilution tunnel hood that collects exhaust gas and mixes it with room air. The dilution ratio is controlled by a set of in-line dampers that allow the air velocity in the dilution tunnel to be adjusted. The dilution tunnels seams and joints are sealed to prevent leakage. The velocity and pressure are measured with a pitot tube and digital pressure gauge through each test. The dilution tunnel has a diameter of 8 inches and meets the specifications of ASTM E Prior to each test series the dilution tunnel is cleaned with a wire chimney brush. PM Measurements Particulate emission measurements were made from a dilution tunnel and conducted in compliance with ASTM E2515 Standard Test Method for Determination of Particulate Matter Emissions Collected in a Dilution Tunnel. Sampling from the dilution tunnel offers a measurement that represents particulates found in the field; particulates form from condensable products in the exhaust gas once it has cooled. The total flue gas exhaust from the wood-fired boiler was collected along with ambient dilution air with a collection hood. Samples were collected from the center of the dilution tunnel at room temperature and a preset sampling rate specified prior to the test. The rate was within the acceptable range offered by ASTM E2515 of.1 to.25 cubic feet per minute, most often at.2 cubic feet minute (cfm). Two identical dual-filter EPA Method 5 sampling trains 1 were operated simultaneously. The two sampling trains allowed for quality control and confirmation of the PM data collected over a period. Each sampling train consisted of two glass fiber filters in series that are each 47 millimeters in diameter, which is in agreement with the filter holder assembly stipulations imposed by ASTM E2515. Filters and probes were desiccated for at least 24 hours or until the weight remained constant. The components were weighed prior to the test. The probes were also rinsed with acetone before sampling and initial weights are taken to remove any PM that may have accumulated in the probe from prior tests. When loading and measuring any filters and probes, gloves and tweezers were used to eliminate excess weights attributed to dirt and oils from skin contact. Leak checks of the sampling system were performed before ignition of the boiler to ensure no leakage exists that would result in less dilution tunnel gas passing through the filters than indicated by the metering system. The mass of the sampled particulate matter was combined with any additional matter collected on the sampling probes and measured after desiccating the filters and probes over a 24-hour period to remove any moisture. The dilution tunnel air to exhaust gas ratio was also measured throughout a test because the dilution tunnel flow to sample flow was used to determine the total particulate emissions during a test. Leak checks were also conducted at the conclusion of the test. Leakage rates were no more than the acceptable.1 cfm. Leak checks were not performed between sampling periods to minimize the sampling time lost during filter changes. 1 Model 511 from Apex Instruments 5

9 Flue Gas Analysis Flue gas samples for analysis were taken from the dilution tunnel and directly from the flue. For sampling from the dilution tunnel, water vapor was removed using a thermoelectric cooler/drier. Gas analysis in the dilution tunnel included oxygen and carbon monoxide. Analysis of samples from the flue gas included oxygen. A decision was made to measure carbon monoxide from the dilution tunnel to allow direct calculation of the emission rate of CO (concentration dilution tunnel flow rate). Carbon monoxide was measured using a Rosemount Analytical model 88 NDIR Carbon Monoxide analyzer. Oxygen was measured in both the dilution tunnel and the hot stack via a Beckman model 755 Oxygen Analyzer. Both analyzers have a set of four ranges: 1%, 25%, 5% and 1%. The signals from all analyzers were logged at a 5 second intervals. Fuel Type and Loading The fuel test charge was cordwood, specifically red oak with an average moisture content of 19 to 25% on a dry basis. During testing, fuel pieces were placed in the firebox parallel to the longest firebox dimension. A full load was considered as 1 pounds per cubic foot, which is equivalent to 63 pounds of the fuel charge for the specific appliance at BNL. The test fuel was prepared by the State University of New York, College of Environmental Science and Forestry under the direction of Dr. William Smith. The preparation involved conditioning fresh cord wood under controlled temperature and humidity conditions for time periods on the order of weeks. The purpose of this work at ESF was to develop an accelerated route to production of fuel suitable for test purposes. The specific tests included in this report were done as part of a larger study with this boiler during which many conditions were explored, most of which were different from those included in the formal test protocols. This large number of tests led to a need for an unusually large quantity of test fuel and no source was found for such a large amount of wood naturally seasoned to produce fuel within the target moisture range. The fuel that was used for the tests was free of any notable decay, fungus and loose bark. The fuel charge and kindling was loaded as per the manufacturer s specifications. A detailed description of the loading procedure may be seen below. Kindling was weighed prior to each test; however, moisture of the kindling pieces was not recorded. No additional effort was made to stack the cordwood pieces tightly or loosely with respect to one another. The fuel length was specified as 8% of the firebox s depth, as per the BNL PTS Method, which equated to 18 inches. The cold start light-off procedure used in the Category I test was as per the manufacturer s instructions, as described in their owner s manual. For the Category I test this included loading the fuel in two batches. These instructions are provided below. 6

10 Econoburn Boiler Initial Light-off Instruction Rev 1.2 Addendum to IOM 3/214 (for boilers with SFD-II rev 1 control) 1. Open Bypass Damper and Loading Door 2. Twist 8 pieces of newspaper and insert in top chamber (24 x24 ) 3. Place dry kindling over newspaper in a criss-crossed manner. Kindling should be <8%MC a. (twigs, kiln dried scrap lumber, etc.) b. Load smallest pieces first on top of newspaper. 4. Place 1% of fuel charge on top of kindling (2-3 inch pieces) as long as newspaper can be easily reached for lighting. If not, load immediately after newspaper has been lit. 5. Power on the electronic boiler control. Scroll to Boiler Setup 6. Depress enter until you ve reached Stack Temp Setting. 7. Use up/down arrows to 55 F 8. Depress enter until main screen reappears. 9. Scroll to screen that reads Boiler Stopped, Hit Enter To Start 1. Depress Enter Button and ensure that fan has engaged. a. Temporarily interrupt fan with toggle switch located on the side of the blower cover. 11. Light newspaper in various locations. 12. Turn on fan with toggle switch, close the loading door and leave bypass damper open. 13. On Electronic Control, scroll to the screen that displays stack temperature. (left or right arrow) 14. Over the course of 5 minutes, the stack temperature should continue to climb indicating that good light-off has been attained. 15. Once stack temperature has reached 55 F (or 5 to 7 minutes has elapsed) turn off fan toggle switch, open the top loading door and visually inspect and ensure that the kindling charge is fully involved in flame and volatizing. 16. If so, insert remainder of fuel charge in the chamber (smallest pieces first) and close door. 17. Turn fan toggle switch back on and close damper 18. Return to Stack Temp Setting screen in the Boiler setup menu. 19. Change Stack Temp Setting to 36 F Wood Moisture Measurements The overall efficiency of the boiler provides a uniform basis for comparison of performance of different units. This is of value to the consumer and is determined through the total energy input, output and losses. The moisture content of the wood factors into the total energy input and therefore moisture measurements of the fuel charge are essential. The average moisture content was determined following the method outlined in NYSERDA report Evaluation of Wood Fuel Moisture Accuracy for Cordwood-Fire Advanced Hydronic Heaters. In summary, the method takes six measurements on each piece of fuel, three at the core level and three at the shell layer, averaging all the data points. Moisture measurements were taken an hour prior to every test. The wood moisture meter used for measurements was a Delmhorst RDM-3, which is capable of 7

11 measuring test fuel moisture to within 1% moisture content (nominal). The meter also allows the user to specify the species measuring to ensure accuracy. Procedures for measuring the moisture content of the test fuel load and tolerances were designated by BNL PTS Method. As per the BNL PTS Method, an acceptable criterion for the test fuel load was 18 to 28% at the individual measurement points with an overall average of 19 to 25%. As mentioned previously, no kiln dried wood was used and moisture was not added to any fuel charges that registered below the acceptable range. Temperature Measurements Temperature data is crucial to the overall operation of the wood boiler. Temperatures were measured continuously at five second increments, using TC-8 thermocouple data loggers made by Pico Technologies with type K thermocouples. Type K thermocouples are capable of measuring temperatures to within +/ The thermocouples were calibrated using an Omega CL1 dry calibration block and were in compliance with National Institute of Standards and Technology (NIST) Monograph 175, Standard Limits of Error. The logged temperatures included: boiler supply, boiler return before mixing, boiler return after mixing; ambient, flue gas; dilution tunnel, tank one supply, tank two supply, tank one return, tank two return, boiler side heat exchanger supply, boiler side heat exchanger return, city water side heat exchanger supply and city water side heat exchanger return. The applicable wood fired boiler for these tests also provided its supply temperature and the flue gas temperature in the control panel display; however these values could not be automatically logged and only manually recorded periodically. 8

12 Analysis of Efficiency Different definitions of efficiency are often applied to combustion systems, and may cause confusion. The term thermal efficiency is most commonly defined as measured energy out divided by measured energy in, and this definition was used in this report. The term combustion efficiency is sometimes defined as the fraction of the chemical energy in the fuel that is converted to heat. Gullett et al. defined incomplete combustion, leading to CO, unburned hydrocarbons and particulate carbon, as the only factors that lead to combustion efficiency less than 1% 2. In other cases, the term combustion efficiency refers to 1% - energy loss due to sensible and latent heat in the flue gas and unconverted carbon (including CO). This definition is used, for example, in the BTS 2 test method for commercial boilers published by the Air- Conditioning, Heating, and Refrigeration Institute (AHRI). In other sources, this same efficiency is termed stack loss efficiency or SLM 3. In this report, SLM refers to the Stack Loss Method and the term Combustion Efficiency is used for efficiency determined using a Stack Loss Method. Evaluation of the thermal efficiency for a burn cycle was done using an energy input/output method as guided by the BNL PTS Method. Depending on the conditions used, the components considered in the energy output included energy to the heat exchanger, energy stored in the water in the storage tank or tanks, energy stored in the steel of the storage tank, energy stored in the boiler water, energy stored in the boiler steel. Some attempt was also made to calculate the energy stored in the piping between the boiler and the storage tank (both water and copper piping). This amount of energy was found to be very small. The BNL PTS Method also calls for evaluation of the efficiency using a stack loss method. Here the efficiency is 1% - losses due to sensible and latent heat in the flue gas and energy lost due to incomplete combustion. This method in the BNL PTS Method is referenced from CSA B Average carbon monoxide in the flue over 1 minute intervals was calculated from the CO in the dilution tunnel and other inputs using the following steps: 1. From the dilution tunnel CO measurement and the dilution tunnel molar flue gas flow, the CO emission rate in g/min was determined. 2. From the dilution tunnel CO emission rate, flue gas oxygen content and the average wood combustion rate over the 1 minute interval, values of excess air and fraction of the fuel carbon converted to CO instead of CO2 was calculated using an iterative procedure. These values were calculated to give the same CO emission rate as in the dilution tunnel and the measured flue gas oxygen content. This procedure allowed direct calculation of the flue gas CO concentration. From the flue gas CO content, flue gas oxygen content, and flue gas temperature the combustion efficiency was determined using the approach referenced in CSA B Gullett, B. et al. Environmental, Energy Market, and Health Characterization of Wood-Fired Hydronic Heater Technologies, U.S. EPA report to NYSERDA, NYSERDA Report 12-15, June Canadian Standards Association, CSA B

13 Phases of the Burn Period The BNL PTS test method describes a methodology for breaking the emissions into three phases: startup, steady state, and end. During the more extensive test program with this boiler at BNL, the transition points between these phases was developed based on the measured carbon monoxide. During startup (hot or cold), flue gas CO was very high. After the charge has lit and the gasification/combustion process was proceeding correctly, the CO emissions drop to a very low, steady state value. The startup phase was considered to be completed when the CO became low and remained low for approximately 15 to 2 minutes. In a similar way, near the end of the steady state phase flue gas oxygen and CO emission started to rise. Based on many test runs at BNL, the BNL PTS method calls for the end of the startup phase when 15% of the fuel charge has been consumed. The end of the steady state period is identified in BNL PTS when 8% of the added fuel charge has been consumed. 1

14 Results Category IV Table 2: Summary of Conditions for Category IV Test Test Date April 1 st, 214 Fuel Load Storage Tank Volume Condition Cord Category IV 4 gal (nominal) Hot-to-Hot Discussion of Test Condition One important objective of this test is to show that the boiler can perform at its rated output for Category IV according to the BNL PTS Method. During this test all heat was sent to the heat exchanger and the storage tank was not used. Discussion of Test Results According to the BNL PTS Method, a pre-charge burn of 63.5 lbs (comprised of 6.2 lbs of kindling and 57.3 lbs of cordwood) and moisture content of 21.2% was completed to create a coal bed. After the establishment of the coal bed, the test charge was added and the test started at 1:1 pm. The coal bed established was in compliance with the BNL PTS Method, which states a coal bed between 1 and 2% of the total fuel charge. A coal bed of 17% was achieved. The duration of the test was 89 minutes to consumption of the test fuel charge. The boiler controls adjusted the ID fan speed to 7% or greater for the whole test period, indicating the unit was running at maximum output. The added fuel charge was 65.4 lbs. Average moisture content of the fuel charge was 26.9%. Moisture content was determined following the method outlined in NYSERDA report Evaluation of Wood Fuel Moisture Accuracy for Cordwood-Fire Advanced Hydronic Heaters. Particulate sampling in the dilution tunnel was done over three different time periods. The first time period, was approximately 15 minutes and represented the startup period, consuming 15% of the fuel charge. Figures 4 through 15 shaded in yellow represent this. The second time period had a duration of 5 minutes and represented the steady state test period, consuming 8% of the fuel charge, and is shaded in green in Figures 4 through 15. The final sampling time period began after the stead y state period, and ended once the added test fuel charge was completely consumed. This period had a duration of 2 minutes, and is indicated in Figures 4 through 15 with red shading. The fuel used in the startup, steady state and end test periods was 1.3, 4., and 11.4 lbs., respectively. Note that the sum of each period does not amount to the entire fuel charge; this loss is associated with t h e few minutes required for filter changes between test periods. The figures show that there were several periods, well after startup where the CO became very high, indicating poor combustion. These times can be seen to correlate with periods of low flue 11

15 gas oxygen. The reasons for this control system behavior are not known. The overall particulate emission factor for this test, including all three periods, was.83 lb/mmbtu. The energy output for the entire test period was determined considering the heat output to the heat exchanger, the rise in temperature of the storage tank, the change in temperature of the boiler steel and water, and the change in temperature of the connected piping and water in the piping. Energy input was determined for the fuel charge based on average moisture content. For the entire test period, the thermal efficiency was calculated at 57.1%. The fuel-use weighted Stack Loss Method (SLM) efficiency w a s determined to be 64.7%. Wood moisture data for this test is provided in Tables

16 Table 1: Cat. IV Pre-Charge Data Piece Weight (lbs.) Moisture Reading (%) Point A Point B Point C Shell Core Shell Core Shell Core Table 2: Summary of Cat. IV Pre-Charge Load Total avg. moisture (%) 21.2 Weight of fuel charge (lbs) small kindling pieces (lbs) 6.2 Total weight (lbs) 63.5 Table 3: Cat. IV Fuel Charge Data Piece Weight (lbs) Moisture Reading (%) Point A Point B Point C Shell Core Shell Core Shell Core

17 CO in dilution tunnel (ppm) Table 4: Summary of Cat. IV Fuel Charge Load Total avg. moisture (%) 26.9 Weight of fuel charge (lbs) 65.4 Total weight (lbs) PRE-BURN Figure 4: Cat. IV CO in dilution tunnel 14

18 Mass of wood burned (lbs) Oxygen % in Stack PRE-BURN Figure 5: Cat. IV Flue gas oxygen content PRE-BURN Figure 6: Cat. IV Cumulate loss of pre and fuel charges 15

19 Boiler Temperature (F) Stack Temperature (F) PRE-BURN Figure 7: Cat. IV Stack temperature PRE-BURN Figure 8: Cat. IV Average boiler temperature 16

20 Emission Rate (g/hr) Emission Factor (lb/mmbtu) Train 1 Train Start Up Steady State End Sampling Period Figure 9: Cat. IV Particulate factors Train 1 Train Start Up Steady State End Sampling Period Figure 1: Cat. IV Particulate emission rates 17

21 CO emission rate (g/min) Emission Index (g/kg fuel) Train 1 Train Start Up Steady State End Sampling Period Figure 11: Cat. IV Particulate emission index PRE-BURN Figure 12: Cat. IV CO emission rate 18

22 Fuel Consumed (lbs) CO (ppm) Figure 33: Cat. IV Calculated CO in flue, 1 minutes averages Figure 44: Cat. IV Fuel used in 1 minute periods 19

23 Efficiency (%) Figure 55: Cat. IV Calculated stack loss efficiency, 1 minute averages Category I Table 6: Summary of Conditions for Category I Test Test Date April 2 nd, 214 Fuel Load Storage Tank Volume Condition 2 Cord Category I 4 gal (nominal) Cold Start Discussion of Test Condition The purpose of this test was to obtain accurate emissions and efficiency numbers with a cold start and the heat exchanger load set for Category I according to the BNL PTS Method. Prior to the start of the test, the combustion chamber and gasification chamber were carefully cleaned. The boiler s heat exchanger was cleaned using the manual scraper lever arrangement provided as part of the boiler. The 4-gallon (nominal) storage tank was used for the Category I test. Prior to the start of the test, the storage tank was preheated to a nominal temperature of 125 F. The water in the storage tank was circulated for many hours prior to the start to ensure a uniform temperature. The temperature of the boiler at the start of the test was at a mean temperature of 118 F. The boiler operating limit for this test was set at 196 ºF. When this specific unit completes the combustion of a charge of wood the control continues to run the fan. There is no clear indication of the end of a run. For this test the run was ended when the

24 calculated fuel remaining (correcting for water density changes) was very close to zero and the flue gas oxygen rose to 17.5% Discussion of Test Results The boiler gasification chamber was loaded with the full charge of wood, kindling and paper and the test started when this fuel charge was ignited at 11:1 AM. The test ended at 1:59 PM for a total duration of 2 hours and 49 minutes. The boiler controls adjusted the ID fan speed of 7% or higher for the whole test period, indicating that the unit was running at maximum output. This reflects the storage used essentially the boiler was operating as if at full load during the entire time period. Particulates in the dilution tunnel were sampled over three different time periods. The first time period was 2 minutes and represented the startup period. In the figures below, this time period is indicated with yellow shading. The second time period had a duration of 64 minutes and represented the steady state test period. This period is shaded in green in the figures. The third time period had a duration of 78 minutes, and is shaded in red. Note that these weights do not add up to the fuel used during the test period because of the few minutes required for filter 21

25 changes between test periods and unaccounted for mass losses such as heat exchanger section ash deposits. The total fuel charge was 61.9 lbs and average moisture content was 22.6%. Detailed wood moisture data for this test is provided in Tables 7 and 8. Key test results are illustrated in Figures 16 through 27. Figure 16 shows the CO as measured in the dilution tunnel. Ignition in this test was rapid, and CO dropped from the startup peak to the steady state value in about 2 minutes. Figure 17 shows the trend in the measured flue gas oxygen content, and illustrates the typically observed increase in oxygen as the wood charge burns out toward end of the test. Wood consumption rate is shown in Figure 18. Flue gas temperature is illustrated in Figure 19, and boiler water temperature is shown in Figure 2. Particulate emissions are illustrated for each of the three parts of the firing period in Figures 21, 22 and 23. Both EPA Method 5 train box results are shown and are within agreement with each other. Carbon monoxide emission rate, calculated from dilution tunnel flow and concentration is illustrated in Figure 24. Calculated CO in the flue is illustrated in Figure 25. This calculation was done as part of the SLM efficiency calculation, and as required by Standard CSA B415.1, conducted over 1 minute averaging periods. Figure 26 shows the fuel use also averaged over 1 minute periods for the SLM calculation. Figure 27 shows the profile for the calculated SLM efficiency over the whole test period. Based on all results for this Category I test, the following performance parameters were determined: Particulate emissions.166 lb/mmbtu output Thermal efficiency 6.4% SLM efficiency 73.9% In determining the average particulate emission rate in grams per hour for this test, the total period was 1.1 hours. This period included the sum of 2.82 hours of the active burn period and 7.28 hours during which heat would be supplied from the storage tank for the heat load. The 7.28 hours assumed that the tank entered the storage draw period with a temperature of 177 F and ended with a temperature of 118 F. These are the actual temperatures from the Cat. I test. During the storage draw period, the heat extraction rate was assumed to be 15% of the manufacturer s rated heat output capacity. 22

26 Table 7: Cat. I Fuel Charge Data Piece Weight (lbs) Moisture Reading (%) Point A Point B Point C Shell Core Shell Core Shell Core Table 8: Summary of Cat. I Fuel Charge Load Total avg. moisture (%) Weight of fuel charge (lbs) Weight of kindling (lbs) 6.2 Total weight (lbs)

27 Oxygen % in Stack CO in dilution tunnel (ppm) Figure 16: Cat. I CO in dilution tunnel Figure 17: Cat. I Flue gas oxygen content 24

28 Stack Temperature (F) Mass of wood burned (lbs) Figure 18: Cat. IV Cumulate loss of fuel charge Figure 19: Cat. I Stack temperature 25

29 Emission Factor (lb/mmbtu) Boiler Tempearture (F) Figure 2: Cat. I Average boiler temperature Train 1 Train 2.5 Start Up Steady State End Sampling Period Figure 21: Cat. I Particulate factors 26

30 Emission Index (g/kg fuel) Emission Rate (g/hr) Train 1 Train 2 5 Start Up Steady State End Sampling Period Figure 22: Cat. I Particulate emission rates Train 1 Train Start Up Steady State End Sampling Period Figure 23: Cat. I Particulate emission index 27

31 CO (ppm) CO emission rate (g/min) Figure 24: Cat. I CO emission rate Figure 256: Cat. I Calculated CO in flue, 1 minutes averages 28

32 Efficiency (%) Fuel Consumed (lbs) Figure 26: Cat. I Fuel used in 1 minute periods Figure 27: Cat. I Calculated stack loss efficiency, 1 minute averages 29

33 Summary Table 9: Data Summary Part A Category Run No Load % Capacity Target Load Actual Load Actual Load Θ Test Duration W fuel MC ave Qin Q out Wood Weight as-fired Wood Moisture Heat Input Heat Output I II III < 15% of max % of lb % DB Btu Btu Btu/hr Btu/hr max h r 25,5 23, ,1 283, % of max 25-5% of max IV Max capacity 17, 171, , ,481 Table 1: Data Summary Part B T2 Min E T E E E g/hr E g/kg η del η SLM Category Run No Load % Capacity Min Return Water Temp. Total PM Emissions PM Output Based PM Output Based PM Rate PM Factor Delivered Efficiency Stack Loss Efficiency F g lb/mmbtu Out mg/mj g/hr g/kg % % I < 15% of max II 16-24% of max.166* 71.37* * 6.4* _ III 25-5% of max.166* 71.37* * 6.4* _ IV Max capacity * * Not measured. Assumed to be equal to the Category I test results, as per BNL PTS method ** This represents the temperature at which this boiler started. 3

34 Table 11: Data Summary Part C Θ 1 Θ 2 Θ 3 CO_ 1 CO_ 2 CO_ 3 CO T Category Run No Load % Capacity Startup Time. Steady State Time End Time Startup CO emission Steady State CO emission End CO emission Total CO emission I < 15% of max min min min g g g g II III 16-24% of max % of max IV Max capacity Table 12: Data Summary Part D E 1 E 2 E 3 E 1_g/kg E 2_g/kg E 3_g/kg Category Run No Load % Capacity Startup PM Steady State PM End PM Startup PM emission index Steady State PM emission index End PM emission index I < 15% of max g g g g/kg fuel g/kg fuel g/kg fuel II III 16-24% of max % of max IV Max capacity * For category I this includes the startup, steady state, and end phases. For Category IV, this includes only the startup and steady state phase. 31

35 Table 13: Hang Tag Information MANUFACTURER: MODEL NUMBER: ANNUAL EFFICIENCY RATING: ηavg 6.23 (Using higher heating value) (Using lower heating value) PARTICLE EMISSIONS: E avg 2.7 GRAMS/HR (average).162 LBS/MILLION Btu/hr OUTPUT Table 14: Annual Weighting Category Weighting Factor (F i) η del,i x F i E mg/mj,i x F i E g/kg,i x F i E lb/mmbtu Out,i x F i E g/hr,i x F i I II III IV Totals