Flow Rate Estimation Modelling in a Transmission Pipeline Using Response Surface Methodology (RSM)

Yıl 2017, Cilt: 1 Sayı: 1, 22 - 31, 27.12.2017

UĞUR Akyol , TUĞRUL Akyol , A. DENİZ Karaoğlan BEDRİ Yüksel ASİYE Aslan

Öz

The source of geothermal energy to be used for
district heating systems is, in most cases, located some distance from the
heating market, although geothermal water may also be found within the market
area. A transmission pipeline is therefore needed to transport the geothermal
fluid from the geothermal field to the end users. Geothermal fluids can be
transported over fairly long distances in thermally insulated pipelines.
Transmission pipelines of even 60 km length have been built with acceptable
heat loss values, though shorter transmission distances are much more common
and clearly more desirable. At flowing conditions, the temperature drop in
insulated pipelines is in the range of 0.1 to 1.0°C/km, while in uninsulated
lines it is 2 to 5°C/km (in the range of 5 to 15 l/s flow for
15-cm diameter pipe).

 

In addition to a group of parameters, which are almost
constant, such as the length, diameter, thickness, thermal insulation
properties and material type of the pipeline, whether above ground or buried
and so on, temperature drop rate in transmission pipelines is strongly affected
by flow rates. At low flow rates, the temperature drop is higher than that of
greater flow rates. The temperature drop depending on the flow rate becomes
more apparent for relatively long pipelines.

 

In this study, the temperature drops in the
transmission pipeline of the Bigadiç geothermal district heating system (GDHS),
a buried 18 km long pipeline, is investigated for varying flow rates. Response
Surface Methodology (RSM) is then used for modelling and estimating the flow
rate depending on the temperature drop in the pipeline. The results show that
the flow rates given by the model (with R²,
coefficient of determination, of 96.67%) are in a good agreement with those
measured by the flowmeter.

Anahtar Kelimeler

District heating system; Flow rate; Response Surface Methodology (RSM); Transmission pipeline

Kaynakça

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