District Heating Impact Assessment

As a special case of the area-source module (designed for very large number of individual domestic, commercial, industrial or traffic related diffuse or area sources), this module is based on a long-term simulation model. It uses a version of the ISC LT model, A similar kernel approach traffic generated pollution. is used. This makes model performance less dependent on the number of emission sources, and allows to include thousands of individual buildings in an emission scenario.

The module includes:

A building heating data base that manages the energy and emission data for individual buildings or blocks of buildings. The data include basic information on the building or block of buildings, energy data, and heating system (fuel and type) specific emission rates for a group of substances.
emission inventory

A scenario editor that supports the selection of

a long-term meteorological (frequency distributions) scenario;
a building block selection.
The selection of buildings (that will or will not contribute to the emission scenario) can be based on their attributes, using a multi-criteria filtering and ranking approach, or manually, from the map display.
Selecting a building represents its connection to the district heating system, and thus switching off its individual emissions.
A special case it the automatic multi-criteria selection (up to the available heating capacity provided by an appropriate power plant or set of plants) of buildings, sorted by user defined selection criteria, including proximity to an existing or planned pipeline system.
emission inventory editor building block selection emission scenario

The basic simulation module; this involves the simulation of a base line scenario (no buildings connected), the selected scenario (some buildings connected to the power plant), and the simulation of the power plant itself.
The emission and dispersion simulation is based on a Gaussian long-term model (ISC-3/AERMOD with complex topography corrections), and a long-term weather scenario (frequency distributions) for the default period of October 1 to March 31 (compatible with 96/62/EC and COM(97)500).
dispersion modeling weather scenario frequency analysis

An assessment module, that compares the two scenarios, with and without the district heating scheme, and calculates the resulting difference in terms of ambient air quality and population exposure.
scenario comparison

Case study application: TPS Donaustadt, Vienna, Austria

The first implementation was developed for the new (planned) 350 MW gas fired plant (gas/steam turbine) which will supply up to 250 MW of district heat. With an efficiency of up to 86% (power and heating combined), it will be one of the most modern and efficient plants in operation: older power plants reach an efficiency of around 40%.

The new block 3 of the Donaustadt TPS complements the existing blocks in Vienna's three major power stations, including Simmering (5 blocks with a total of 1050 MW electrical, and heat capacity of up to 630 MW) and the TPS Leopoldau with 155 MW electrical and 170 MW thermal.

The technical planning data for the new, third block for Donaustadt (current capacity in blocks 1 and 2 is 304 MW electrical) are as follows:

Gas turbine electrical output heat output efficiency
(without heat coupling) efficiency
(with heat heat coupling)
240 MW 350/300 MW 0/250 MW 58 % 86 %

The building and emission data base covers more than 7,000 blocks, and includes data for SO2, NOx, CO2, CO, PM10, heavy metals (lead and cadmium), and HCH0 and PAH. Residential and commercial use, heating systems (individual or central) and fuel types (solid (coal), liquid (oil) and gas), all expressed as fractions of the total energy consumption, are recorded for each building.