Simulation and optimization of a CHP biomass plant and district heating network

Sartor, Kevin; Quoilin, Sylvain; Dewallef, Pierre

doi:10.1016/j.apenergy.2014.01.097

Cited by 127 publications

(89 citation statements)

References 9 publications

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“…The feeder pipe, which has a minimum distance of 6.6 m from the boreholes, was simulated with a surface heating element. The heat loss (150 W/m length) was calculated based on temperature measurements inside the feeder pipes for the year 2011 [46]. The SEGI is located close to the boreholes at a minimum distance of 15 m. The heat loss through the foundations of the SEGI building was simulated by imposing a constant temperature through time (17.7 °C) at the whole building surface, as measured by temperature data loggers at the basement of the building.…”

Section: Analysis Methodologymentioning

confidence: 99%

Effect of undisturbed ground temperature on the design of closed-loop geothermal systems: A case study in a semi-urban environment

et al. 2017

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This paper presents temperature measurements in four Borehole Heat Exchangers (BHEs), equipped with fiber optics and located in a semi-urban environment (campus of the University of Liege, Belgium). A 3D numerical model is also presented to simulate the heat loss from the surrounding structures into the subsurface. The mean undisturbed ground temperature was estimated from data during the preliminary phase of a thermal response test (water circulation in the pipe loops), as well as from borehole logging measurements. The measurements during water circulation can significantly overestimate the ground temperature (up to 1.7 °C in this case study) for high ambient air temperature during the test, resulting in an overestimation of the maximum extracted power and of the heat pump coefficient of performance (COP). To limit the error in the COP and the extracted power to less than 5%, the error in the undisturbed temperature estimation should not exceed ±1.5 °C and ±0.6 °C respectively. In urbanised areas, configurations of short BHEs (length < 40 m) could be economically advantageous (decreased installation and operation costs) compared to long BHEs, especially for temperature gradient lower than -0.05 °C/m.

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Section: Analysis Methodologymentioning

confidence: 99%

Effect of undisturbed ground temperature on the design of closed-loop geothermal systems: A case study in a semi-urban environment

et al. 2017

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“…The heat losses due to transport (HL DHN ) from plant to buildings vary depending on the linear heat density of the DHN which is defined as the ratio of the annual heat delivered to the total length of the DHN pipes: from 5% for high linear density up to 25% for low linear density [30][31][32]. In this study, transport efficiency is considered to 10%.…”

Section: District Heating Networkmentioning

confidence: 99%

Exergy analysis applied to performance of buildings in Europe

Sartor

Dewallef

2017

Energy and Buildings

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Energy performance of buildings generally assesses the energy consumption of buildings such as heating, domestic heat water, ventilation systems, etc. However, this approach is based on the first law of thermodynamics and considers only the quantity of energy used without considering its 'quality' and leads to a lack of information about the energy conversion processes. This is particularly true in the new low-energy buildings where sometimes high temperatures sources are used to meet low-temperature needs. The exergy analysis of a system, based on first and second thermodynamic laws, can be used to overcome this. In this work, it is proposed to compare the energy and the exergy consumption and the related CO 2 emissions of several kinds of buildings to determine the best systems in terms of energy and exergy needs. The energy demand calculations are performed using the official software available in Belgium and some assumptions are implemented to consider the exergy approach. As exergy calculations require a reference state, some different climatic conditions are also investigated. Finally, some conclusions are discussed to rank the sources of energy and their related exergy losses.

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“…The feeder is simulated with a surface heating element. The heat loss (150 W/m length) is calculated based on temperature measurements inside the feeder pipes (Sartor et al 2014). The heat loss through the foundations of the SEGI building is simulated by imposing a constant temperature through time (17.7…”

Section: Undisturbed Ground Temperaturementioning

confidence: 99%

Fiber-optic temperature measurements in closed-loop geothermal systems: A case study in heterogeneous bedrock

et al. 2016

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In order to study the behaviour of shallow closed-loop geothermal systems, four borehole heat exchangers equipped with fiber optics were installed on the campus of the University of Liege (Liege, Belgium) over a surface area of 32 m 2 . This paper presents continuous, high-resolution temperature profiles measured along the boreholes length at different phases: at the undisturbed state, during hardening of the grouting material, during the recovery phase of a Distributed Thermal Response Test (DTRT) and during a DTRT of a long duration (7 months). The undisturbed ground temperature is affected by the heat loss from ground structures located close to the boreholes, as also indicated by a 3D numerical model. Temperature profiles during hardening of the grouting material indicate extended fractured zones in the rock mass. Temperature measurements during the recovery phase can be correlated to rock layers with different mineral content. The results are in good agreement with those of the borehole televiewer logging method. The long duration DTRT allow us to follow the thermal plume in the heterogeneous rock mass. Moreover the effect of the duration of the test to the calculated mean thermal conductivity and borehole thermal resistance is investigated. The presented analysis could provide information on bedrock heterogeneity, on the anisotropic thermal behaviour of the rock mass and on the ground temperature variations due to heat loss from ground structures. These information could significantly contribute to the long-term behaviour prediction of the geothermal system and the geothermal reservoir potential. INRODUCTIONIn order to study the behaviour of closed-loop geothermal systems in heterogeneous bedrock, four Borehole Heat Exchangers (BHEs), namely B1 to B4, were installed on the campus of the University of Liege (Liege, Belgium) over a surface area of 32 m 2 (Radioti et al. 2013). The four BHEs, equipped with double-U geothermal pipes of 100 m long are located at a distance of approximately 15 m to a building (SEGI) and 6.6 m to an underground structure (feeder pipe) (Fig. 1).After drilling the boreholes, a borehole televiewer was lowered inside the four boreholes. A detailed bedrock characterisation was conducted based on acoustic borehole imaging data, gamma-ray logging data and cuttings observation (Radioti et al. 2015a). • SE. Moreover, azimuth and deviation were measured by magnetometers and inclinometers (Monier-Williams et al. 2009). Based on these data, the horizontal distance through depth between B2 and the other three boreholes was estimated and presented in Figure 2. B1 and B2 are characterised by roughly the same lithostratigraphy, which is observed at different depths in B3 and B4, due to the layer dip angle orientation. The distance through depth between B1 and B2 oscillates around 4.1 m. The distance between B2 and B3 or B4 decreases through depth, becoming almost the half at the bottom of the boreholes.During the installation of the geothermal pipes, fiber optic cables were attached al...

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Simulation and optimization of a CHP biomass plant and district heating network

Cited by 127 publications

References 9 publications

Effect of undisturbed ground temperature on the design of closed-loop geothermal systems: A case study in a semi-urban environment

Effect of undisturbed ground temperature on the design of closed-loop geothermal systems: A case study in a semi-urban environment

Exergy analysis applied to performance of buildings in Europe

Fiber-optic temperature measurements in closed-loop geothermal systems: A case study in heterogeneous bedrock

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