Multiple pipe system

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Multiple pipe system
RTD Workshop - Brussel 21-22 October 2004 Finn
Bruus, Carl Bro Group
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Agenda

• District heating must demonstrate
  competitiveness supplying new buildings as well
• What is the problem- background ?
• What is the challenge ?
• Recommendations, based on the Danish situation
  and experience
• Prospects

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Background
District heating in Denmark is serving around
half the market for space heating by
approximately 400 district heating companies. The
share is expected to grow a figure up to 65
has been mentioned.
Expansion can only be attained by either
connecting small villages or by increasing market
share in existing supply areas and DH must
demonstrate competitiveness
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Background
Expansion in outlying districts have some common
characteristics

• Unit heat consumption in newer buildings are
  still decreasing -
• In the combination with perhaps increasing
  distance between houses the situation is
  worsening

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Background

• Incentive
• Directive 2002/91/EC of the European Parliament
  and of the Council on the energy performance of
  buildings
• National aims
• Reduction in energyconsumption for new building
  in the range of 25-30
• All merged into an update of national building
  regulations
• BR 2005 new energy performence criteria

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Background
Future energy consumption, scope of
problems Today energy consumption for space
heating, ventilation and hot water is calculated
to an average of 18,1 MWh per year for an
existing one family house -130 m2
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Background
Allready today latest the heatdemand is lower
The National building regulation in force
BR95/BS98 determines the same 130 m2- house to a
maximum heat demand for 12,7 MWh pr. year.
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Background
The 130 m2- reference house are facing the
development
Average today
New buildings
BR 2005
Best practice
Water heated
Electricity
30
25
50
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The challenge
In a design model
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The challenge

• a decresing heat demand effect the economy in
  district heating supply

• How may this development influence the design
  criteria , looking at a distribution network?

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Recommendation
Some answers from a research project District
Heating Supply to Areas with Low Heat Demand an
RD project commissioned by the Danish Energy
Authority Reported March 2004 The
objective Was to identify the optimal
distribution system design with regard to total
distribution costs for an investment period
approaching area with low heat density Focus
point from this project
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Recommendation
Reason no 1 Pipes supporting one or only few
consumers, have an significant effect on the
total economy, because there is so many of them
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Recommendation
2 At the same time the smallest pipes are only
representing a negligible distance compared to
total distance from plant to consumere
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Recommendation
3 The peak flow only take place in a relatively
short period i the smallest pipes compared to
larger pipes because individual consumers are not
in need of peak flow at the same time.
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Recommendation - perspective
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Recommendation
Results from the project optimisized design
layout insulation
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Recommendation
Results optimisized design layout insulation
2
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Recommendation
Results optimisized design layout criteria -
Distribution network
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Recommendation
Summarised outputs saving potential schematically
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Recommendation
Major part of the average temperature loss take
place in the distant pipes, mainly supply pipe to
the customer
Using efficient supply pipes a reduction in heat
losses all the way back to the plant is a bonus
outcome
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Prospects
Technological improvements Development of new
pipeprofiles
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prospects
Description of an experimental test
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prospects
An experiment Development of new pipe profiles -
tripplepipe
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prospects
Tripple pipe ideas behind the experiments
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prospects
An experiment Development of new pipe profiles -
tripplepipe
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prospects
Technological improvements Development of new
components
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prospects
Energy consumption for local pumps is
insignificant
Energy needed for local pump is less than 1 of
total supply pipe and installation-unit need
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prospects
Summarized the analyses indicate focus points in
the distribution network as follows
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prospects
The findings presented for a planning mode-
Prize/ heat density ratio
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prospects
Findings expressed differently

• Downsizing pipes in connection with optimized
  insolation for pipes supporting the outlying
  10-20 singlefamily houses in the street
• Saves 10-25 in total distribution costs
• Saves 20-50 in heat loss (energy)

Based on basic assumptions Investment according
to NPV methods, period 20 years, rate of interest
3 and constant heatprice 40 /MWh.
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Prospects - summary
Analysing distribution networks in the
perspective expansion in outlying districts
indicate a cost saving potential.
Revised design criteria towards accurately design
in combination with latest development of pipes
and components will contribute to increased
feasibility of district heating.
The amount of savings is depending on specific
heat price prognoses for future prices,
investment period, rate of interest and the
distribution network geometry
Thank you!