district heating support tool
TRANSCRIPT
District Heating Support Tool
To Assist in development of feasibility study
Functions of the toolo A least cost routing algorithm to
assess dig costing’so Creates network and applies a 24
heat load profile across the entire network
o Computes pipe sizes (low grade 3-90oC) for desired pressure drop
The Tool - Walkthrougho Still a works in progress so there
are some elements not yet developed
o Start with three geometric inputso A Dig Cost Rastero Buildings to be queried (MM) o Heat Site or Station
Input – Heat Stationo Polygon Area
for Heat Source
Input – Buildings to queryo Version of the Ordinance Survey Master Map
Building Layero Has additional attributes added
1. Heat Demand for building blueprint2. Building use Type
1. Residential2. Commercial3. Hospital4. Leisure
3. Connection Cost for each premise4. Projected Income from heat sales ( energy inflation
of 5% ) over 25 Years minus the Connection Cost
Input – Buildings to query
Input – Cost Rastero Coverage for the dig cost to
traverse a medium (£/m) o Based on national land usage
databaseo Some modelling carried out to
deduce traversable regionso Derived from Polygons e.g
Input – Cost Raster e.g
Input – Buildings to queryHeat Demand
o Heat Demand derived from 3 sourceso University College London Lookup
table as part of the low carbon framework project undertaken in 2012
o LIDAR datao Local Land & Property Gazetteer
Input – Buildings to queryHeat Demand
o LIDAR used to determine average heights
o Average number of floors deduced from UCL lookup table with Building classifications from the LLPG
o MM Building area used with UCL table to provide an annual Heat usage per square meter (KWhthermal per annum)
The Modelo Using the cost raster the model
works out least cost routes to each building from the existing virtual infrastructure
o Selects the most cost effective connection and sketches. This feeds into the next iterative as infrastructure
o The process continues until a user specified cut off condition is reached.
The Model – Output 1
The Model
o Once the initial sketch has been completed the model then applies a connectivity model to the network
o It then take the annual heat consumption for each building and applies a 24 hour heat profile across this. E.g
Heat Profiles
January
February
March
April May JuneJuly
August
Septem
ber
October
November
December
0.0%
2.0%
4.0%
6.0%
8.0%
10.0%
12.0%
14.0%
16.0% Seasonal Heating Requirements
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
RetailCommunity And EducationHotelOfficeFood and DrinkAssembly and leisureAssembly and leisure with poolHealthcare BuildingResidential
The Model o Each buildings load profile cascades back to
the source so the load requirement on each pipe section can be determined
o Using CIBSE pipe sizing formula the model then computes the pipe sizes required for each section for a user specified pressure loss, operating temperature and change in temperature
CIBSE Pipe sizing equations
• Turbulent Flow
5.0
310
5.05 2255.17.3
log2 dpd
kdpM s
5.051
210
5.051 )(7.3
log)(4dpNdN
dkdpNM
l
s
5.053
410
5.053 )(7.3
log)(4dpNdN
dkdpNQ
l
s
30842.032
2
1 N
98567.04255.1
2 N
12
3 30842.032
N
14 98567.0
4255.1
N
The Model – Output 2
Potential Developmentso Not yet finished o Pipe infrastructure cost o Return flowso Cut-off based on heat capacityo Pump sizing o Heat station type & costingo Electrical profiling and distributiono Improved financial modelso Suggestions Welcome