Joensuu 12'6'2006

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Joensuu 12.6.2006

• Determining the need of heating power
• Determining the size of solid fuel boiler
• Scaling of the district heating network
• Acquisition of the heating plant
• veli-matti.alanen_at_jsp.fi

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The need of heating power in the house

• Demand of the heating is based of
• Conduction to air and ground
• Pre-heating of changed air, ventilation
• Heating of leakage air
• Warming of hot tap water
• Demand of the heating power is the sum of these
  details minus inner heat sources and sunshine
• In practice we use typical key figures, e.g. 22
  W/m³, excluding power demand of hot tap water
  heating
• To a single house the power demand for hot tap
  water must always be calculated when choosing the
  boiler
• The size of a boiler depends of volume of
  existing hot water tank

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The need of heating power in the house continues..

• Determining the output demand according the old
  boilers
• Plates on the boiler tell only the theoretical
  maximum output
• Jets of oil burner tell the effect that is lead
  to the boiler, estimated efficiency gives you the
  output to the water
• A person whos answering for boilers can tell how
  long times the oil burners run
• Light fuel oil holds appr. 10 kWh/l

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Rules of thump in Finland

• A house needs 20-30 W / m³
• Energy consumption is 40-50 kWh / m³
• Use of wood chips is 12-15 times the use of oil
• Use of pellets is 2,2 kg or 3,3 litres to one
  litre oil
• The loss in district heating network is 20-30 W/m
  and 150-250 kWh/m/a
• These rules are valid, when outside temperature
  is 30 degrees when coldest
• In summer warm water heating is only 10 of
  connection output
• Mean temperature of winter is about -5 ºC, then
  heat demand averages 50 of connection output

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Alternative equipment

• Grates
• Solid inclined grate
• Moving grate
• Plane grate
• Wanderrost
• Spreader stoker
• Exhaust cleaners
• Cyclone for particles more than 0,01 mm
• Multicyclone
• Scrubber takes over 90 of particles over 0,005
  mm
• Electrostatic precipitator for small particles
  and good cleaning result

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Determining the size of the solid fuel boiler

• Traditional way Up to 500 kW solid fuel boiler
  is sized according to total output demand and in
  over 500 kW plants solid fuel boiler is sized
  appr. 50 of the total output
• When solid fuel boiler is 50-60 of the total
  output, it can make 85-90 of the total energy
• Oil boiler is a secondary boiler covering peak
  loads and summer time during the overhaul of the
  main boiler
• Advantages Cheaper investment, better function
  in summer time, good efficiency (most of the year
  load is 50-80 )
• Alternative way Sizing main boiler bigger we are
  able to use expensive oil less. It puts high
  demands to combustion control, because the solid
  fuel boiler has to work well on very low level,
  10-15 . Also the efficiency has to be good on
  low load.

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Directive table for sizing district heat pipes,
flow speed 0,8 m/s
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Acquisition of the heating plant

• Alternatives
• Sell me a 100 kW boiler plant
• Sell me a 200-2000 kW boiler, fuel feeding and
  combustion system, controlling system and exhaust
  gas equipment, Ill take care of building
  process
• Offer us a detailed part of 3 MW boiler plant
  according to our acquisition program
• Acquisition program in 200-2000 kW size is not a
  list of equipment, and definitely not a list of
  products or trademarks that should be used.
• Acquisition program is a list of needs and
  demands and levels, that should be reached
• Output with sizing fuel nominal effect
• Efficiency (actually details that affect to it
  flue gas temperature, CO, unburned volatiles, ash
  losts )
• Minimum and maximum sizes of equipments
• And so on

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Acquisition program

• Storage large enough (5 days or more?, )
• Storage suitable for fuel transportation vehicles
• Level of automation, on/off or logic?
• Main boiler to half or maximum output, need for
  secondary boiler
• Exhaust gas cleaners
• Height of chimney, according to surroundings
• Ash removing, storing and treatment
• Fire safe equipments
• District heating pumps and controlling device
• Expansion unit
• Alarming unit, remote monitoring, remote
  controlling?
• Social premises

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Tender asking

• No lists of detailed equipments, but limits and
  levels for outfits, fuels and capacities
• Description of the target ( houses or industrial
  estate, single building or network, surrounding)
• Content of tender, total delivery or which parts
• Technical demands
• Sizing fuel, quality and moisture
• Other possible fuels, single or mixture
• Max and min output with sizing fuel
• Pipes and pumps
• Fuel storage, size and conveying units
• Chimney and exhaust gas treatment
• Alarm and remote control
• Schedules
• Limits for delivery

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Tender

• Price VAT
• Schedules
• Payment
• Delivery
• Guarantee, time and content
• Description of delivery, outputs, sizes,
  manufacturers, materials
• Need of electricity
• Practicability time when fully useable,
  normally min 95
• Solid fuel boiler, critical issues
• Min and max output with sizing fuel
• Exhaust gas temperature, O2 and CO content on 50
  (and 100 ) output

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Final assignment

• Written instructions and personal training (13
  days)
• Diagrams of connections
• Testing period, one week without faults
• Measuring of guaranteed capacity figures
• Sanctions
• Output too low ?price reduction
• Use of electricity higher than guaranteed
  ?compensation for 10 or 15 years according to el
  price
• Efficiency too low ? compensation e.g. 2 of
  total price for every -unit
• Practicability ? compensation according to
  difference of fuel prices
• Flue gas emissions ? no compensation, correction

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Control measurements