Laboratory Manager at ClearStak, an EPA-approved Laboratory for Residential Wood Heaters, Willington, Connecticut, USA.
Policy and Program Director at NESCAUM, Boston, Massachusetts, USA.
J Air Waste Manag Assoc. 2022 Jul;72(7):679-699. doi: 10.1080/10962247.2022.2070297.
Many believe that certification testing of residential wood heat appliances should provide data indicative of installed performance. Operationally, test methods typically only assess steady-state emissions and fail to include other typical conditions for batch appliances such as start-up. From a fueling perspective, protocols should ensure a consistent approach reflecting common use practices. Ensuring representative conditions and accurate quantification of emissions requires assessing the impact of different start-up conditions and whether or not start-up conditions affect appliance operation during start-up and beyond. This study evaluated the impact of modifying fuel piece sizes and configurations using a "smart" wood-fired hydronic heater (WHH) cordwood appliance. The appliance represents technologies using software and oxygen sensors to improve performance. Since the study used a "smart" appliance, the results likely reflect the least amount of variability found in a WHH cordwood appliance. The analysis consisted of a series of tests that involved changing one fuel variable per series, including: (1) kindling fuel arrangement in the firebox; (2) fuel piece size; and (3) the amount of kindling and starter fuel used. A goal of the study was to determine how each variable affects emissions performance during start-up and the following steady state load. Testing used a dual-stage combustion cordwood WHH equipped with external thermal storage. Particulate matter (PM), carbon monoxide (CO), and delivered heating efficiency were measured, and visible emissions from the stack and secondary combustion chamber were observed. Replicate tests were conducted for each protocol series to evaluate WHH performance reproducibility. These tests found that for a low-mass staged combustion WHH with external thermal storage, the use of different fueling protocols can substantially affect PM and CO emissions. As test methods move to incorporate measurements beyond steady-state emissions, fueling protocols must be assessed to determine (1) if they reflect typical field procedures and (2) the impact of start-up procedures on the complete test run. This paper assessed how changing start-up conditions affected run variability and PM emission impacts.
许多人认为，住宅木材燃烧设备的认证测试应该提供安装性能的指示性数据。在操作上，测试方法通常只评估稳态排放，而不包括批处理设备的其他典型条件，例如启动。从燃料的角度来看，协议应确保采用一致的方法，反映常见的使用实践。确保代表性的条件和准确的排放量化需要评估不同启动条件的影响，以及启动条件是否会影响设备在启动期间和之后的运行。本研究评估了通过使用“智能”燃木水力加热器（WHH）薪柴器具修改燃料块大小和配置的影响。该器具代表了使用软件和氧气传感器来提高性能的技术。由于该研究使用了“智能”器具，因此结果可能反映了 WHH 薪柴器具中发现的最小变化量。该分析包括一系列测试，其中涉及每次系列测试改变一个燃料变量，包括：（1）在燃烧室中布置引火燃料；（2）燃料块的大小；以及（3）引火燃料和启动燃料的用量。该研究的目的之一是确定每个变量如何在启动期间以及随后的稳态负载下影响排放性能。测试使用配备外部热存储的两级燃烧薪柴 WHH。测量了颗粒物（PM）、一氧化碳（CO）和输送的加热效率，并观察了烟囱和二次燃烧室的可见排放。为每个协议系列进行了重复测试，以评估 WHH 性能的可重复性。这些测试发现，对于具有外部热存储的低质量分阶段燃烧 WHH，使用不同的燃料协议可以大大影响 PM 和 CO 的排放。随着测试方法向稳态排放以外的测量方法发展，必须评估燃料协议，以确定（1）它们是否反映了典型的现场程序，以及（2）启动程序对整个测试运行的影响。本文评估了改变启动条件如何影响运行变异性和 PM 排放的影响。
