Search

This paper presents the preliminary experimental results of a liquid desiccant cooling system driven by the flue gas waste heat of a biomass boiler. The desiccant cooling system is mainly composed of a regenerator, a dehumidifier and an evaporative cooler. The flue gas waste heat is applied to the regenerator to regenerate the desiccant solution. The environmentally friendly liquid desiccant potassium formate (HCOOK) solution is used in the dehumidifier for air dehumidification due to its less corrosion, lower cost, lower density and lower viscosity. A cross-flow heat and mass exchanger for indirect evaporative cooling is adopted in the evaporative cooler to ensure that product air meets the indoor air quality and thermal comfort standard. The desiccant cooling system operated in Autumn days in Nottingham was found to be able to decrease the air temperature by 4°C and reach a cooling capacity of up to 2381 W. Moreover, the dehumidifier is able to reduce the relative humidity of the humid air by 13%. The biomass boiler's flue gas waste heat extracted and supplied to the regenerator was found to be 554 W, which is insufficient to regenerate the dilute liquid desiccant solution under current experimental conditions. To obtain sufficient heat to regenerate the liquid desiccant, the existing first-of-its-kind concentric helical coil heat exchanger extracting the waste heat of the boiler needs to be redesigned, and, in particular, the concentric helical coils of the heat exchanger need to be placed inside the chimney to enhance the waste heat extraction. [ABSTRACT FROM AUTHOR]

Abstract: The present study aims to investigate flue gas emissions, particularly pollutants CO, NO x and particle emissions, of a domestic biomass boiler under various operating conditions. The experimental methodologies are systematically introduced. If the primary and secondary air supply for the biomass furnace are provided by the factory-set openings and vent tubes, the flue gas emissions measured are NO x 54.92 ppmv, CO2 11.98 vol%, CO 0.24 vol%, O2 8.19 vol% and PM0.1–10 concentrations 72.7 mg/Nm3 by burning wood pellets. In addition, the three kinds of cleaning technologies reducing particle emissions are also introduced. [Copyright &y& Elsevier]

Biomass plays an important role in the world primary energy supplies, currently providing ∼14% of the world's primary energy needs and being the fourth largest contributor following coal, oil and natural gas. Over the past decade, domestic biomass heating has received more governmental and public supports than ever before in many developed countries, such as the UK. Although biomass combustion releases some combustion pollutants, biomass is renewable and produces little net CO2 emissions to the atmosphere. Owing to the low sulphur and low nitrogen contents of many biomass materials, substituting biomass for fossil fuels, particularly coal, can reduce SOx and NOx emissions. This study investigated flue gas emissions, particularly carbon monoxide and nitrogen oxides, of a domestic biomass boiler under various operating conditions. The biomass boiler used in this study satisfies the current EU regulation (EN 303-05) on emissions of domestic biomass boilers. Emissions of the boiler had been measured not only under normal combustion conditions, but also under ‘idle’ combustion conditions when the boiler was not in but was ready for full operation. The experimental results are analysed and presented in this paper. [ABSTRACT FROM AUTHOR]