district heating support tool

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