Carbon monoxide emissions of combined pellet and solar heating systems

Abstract

Emissions are an important aspect of a pellet heating system. Low harmful emissions, particularly carbon monoxide, are a measure of a well performing system. High carbon monoxide emissions are often caused by unnecessary cycling of the burner when the burner is operated below the lowest combustion power. Combining pellet heaters with a solar heating systems can significantly reduce cycling of the pellet heater and avoid the inefficient summer operation of the pellet heater. Five combined systems representing the range of typical solutions of this system type and one recently developed system have been studied, modelled and simulated. These systems are compared to a reference system which is based on a pellet boiler and is not combined with a solar heating system. The aim was to study CO-emissions of the different types of systems and to analyse the potential of CO-emission reduction when the pellet heater is combined with a solar heating systems. Another aim was to compare the yearly CO-emissions obtained from simulations under realistic dynamic conditions with the yearly CO-emissions calculated based on the values that are obtained by the standard test methods. The study was performed with the simulation tool TRNSYS. The parameter used in the study have been identified from lab measurements on existing pellet boilers/stoves and solar heating systems. The results from the simulations show that is possible to almost halve the CO-emission if the pellet heater is combined with a solar heating system. The results also show that the CO-emission of existing combined solar and pellet heating systems can be drastically reduced if the pellet heater is properly controlled and some basic design rules are observed. This can also be seen when analyzing the results for the new system concept where these rules have been taken into account. Comparing the yearly CO-emissions obtained from the simulations with the yearly CO-emissions calculated based on the standard test methods shows that using the latter give too low CO-values for the whole year. It is also shown that for the existing systems the average emissions under these realistic annual conditions were greater than the limit values of two Eco-labels.

Flue gases thermal emission concentration during waste biomass combustion in small combustion device with manual fuel supply

“…Thus provided high levels of flue gas temperatures may increase heat loss through increasing flue gas heat. Foreign research works confirm the measuring conclusions that elevated temperature and high combustion air content (5-21%) has a significant effect on the increased production of nitrogen oxides from fuel nitrogen (Eskilsson 2004;Fiedler, Persson 2009). Decreasing amount of combustion air results in reducing nitrogen oxide emissions, but also increase emissions of carbon monoxide in the flue gas.…”

“…By using the closed and controllable combustion chamber in fireplace in- As regards the carbon monoxide emissions, combustion equipment should work as evidenced by other research works in the nominal parameters. Any uncontrolled change of combustion material flow and combustion air leads to high carbon monoxide emissions (Fiedler, Persson 2009).…”

“…Another factor that brings about the higher nitrogen oxides formation is high flue gas temperature, which is caused by overheating of the combustion chamber and by the high excess air coefficient (Hájek et al 2013). Increased temperature in the combustion chamber increases the combustion temperature, which gives rise to high-nitrogen oxides (Fiedler, Persson 2009). A large amount of combustion air in the combustion chamber improves the oxidation reaction of flue gas (Houshfar et al 2011).…”

Exploring the Spatial Heterogeneity of Individual Preferences for Ambient Heating Systems

“…Finally, required own work refers to the time required to ensure the faultless operation of the heating system (e.g., cleaning and handling fuel loads). The choice of attributes and their levels was based on earlier studies [5,34,35] and on feedback from experts. The annual operating cost and CO 2 and fine particle emissions were calculated based on the energy consumption of an average detached house (120 m 2 ), the efficiency of each heating system and unit price/emission of a fuel.…”

On the proper integration of wood stoves in passive houses under cold climates

“…[17,18]). Nevertheless, the present work aims at investigating the limits of the integration of stoves using the standard approach where all the heat is directly released into the room.…”