Small-scale District Heating based on Biomass Joakim Lundgren Division of Energy Engineering Luleå University of Technology

Background Nuclear power phase out Nuclear power phase out A large amount of electricity is today used for heating purposes A large amount of electricity is today used for heating purposes Important to reduce the electricity demand Important to reduce the electricity demand One measure is to convert to district heating – an activity in progress One measure is to convert to district heating – an activity in progress

Background Biomass based district heating for larger communities is well established in Sweden Biomass based district heating for larger communities is well established in Sweden Increasing taxes on fuel oil and distribution network developments have made DH interesting also for smaller communities Increasing taxes on fuel oil and distribution network developments have made DH interesting also for smaller communities Space for at least 10 GW new installed thermal power in small biomass fired DH networks Space for at least 10 GW new installed thermal power in small biomass fired DH networks

Problems Studies show that boilers ( MW) emits large amounts of hazardous products (CO, THC, PAH, VOC) during low and varying heat loads Studies show that boilers ( MW) emits large amounts of hazardous products (CO, THC, PAH, VOC) during low and varying heat loads Economy Economy

EU project Develop a boiler concept suitable for small DH systems Develop a boiler concept suitable for small DH systems Broad thermal output span (10-100%) Broad thermal output span (10-100%) High fuel moisture content High fuel moisture content Manage heat load fluctuations Manage heat load fluctuations Low emissions of harmful products in the complete thermal output span Low emissions of harmful products in the complete thermal output span

Applications Public buildings Public buildings Small industries and shopping centers Small industries and shopping centers Small DH networks in villages Small DH networks in villages …in purpose to change from fossil fuels in existing boilers or to convert from electricity

Layout of the research plant Cyclones Furnace Fuel store Fuel containers Boiler Heat store Chimney To DH network Module 2 Module 1

Primary combustion chamber Gases to the sec. zone Fuel feeding Partitioned combustion chamberPartitioned combustion chamber Drying zoneDrying zone

Secondary zone To the boiler High gas temperaturesHigh gas temperatures Good mixing with combustible gases and secondary airGood mixing with combustible gases and secondary air Designed by using CFDDesigned by using CFD

Experimental results

Conclusions Very low emissions of hazardous products Very low emissions of hazardous products Can manage fuel moisture contents up to 58% Can manage fuel moisture contents up to 58% Can handle heat load variations with kept low emissions Can handle heat load variations with kept low emissions Great potential. 10 GW means approximately 2000 new boilers Great potential. 10 GW means approximately 2000 new boilers

New projects Replacing an oil fired boiler in a school building (Demonstration unit) Replacing an oil fired boiler in a school building (Demonstration unit) BIO-SOL. Biomass based DH in combination with solar energy BIO-SOL. Biomass based DH in combination with solar energy Combustion of horse manure Combustion of horse manure

BIO-SOL Conventional system

BIO-SOL Problem Large heat losses during summer time, calculated as percentage of the generated heat Large heat losses during summer time, calculated as percentage of the generated heat Our idea Let the customers produce their own heat during summer Let the customers produce their own heat during summer

Distributed solar collectors and heat stores

Combustion of horse manure Large costs for depositing waste materials, up to €100 per ton Large costs for depositing waste materials, up to €100 per ton One horse produces 10 tonnes per year One horse produces 10 tonnes per year horses in Sweden, resulting in a total amount of 3 million tonnes annually horses in Sweden, resulting in a total amount of 3 million tonnes annually Year 2005, there will be a prohibition for depositing organic materials Year 2005, there will be a prohibition for depositing organic materials

Very large economical benefits for stable- and trotting course owners Very large economical benefits for stable- and trotting course owners Decreasing the demand for fuel oil and electricity Decreasing the demand for fuel oil and electricity The only condition is that the combustion process must be environmentally friendly The only condition is that the combustion process must be environmentally friendly Combustion of horse manure

Experimental results