The design of thermal tunnel energy segments for Crossrail, UK

Nicholson, Duncan; Chen, Qing; Silva, Mike de; Winter, Alan; Winterling, Ralf

doi:10.1680/ensu.13.00014

Cited by 41 publications

(16 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The influence of the distance between the pipes in the lining and the tunnel intrados (i.e., the pipe embedment) is investigated by considering that a minimum distance of 200 mm is often required to protect pipes from fire effects (Nicholson et al, 2014). To be representative for any thickness of tunnel linings, the pipe embedment is expressed in normalised form via the ratio between the distance from the intrados, s [mm] i , and the lining thickness, t [mm] l , i.e.…”

Section: Pipe Embedmentmentioning

confidence: 99%

“…With most of the lines built underground and 162 km of tracks excavated using full face tunnel boring machines, the 'Grand Paris Express' offers a major opportunity for implementing energy segmental linings. This implementation would follow one energy segmental lining project constructed with subsequent actual energy exploitation (Frodl et al, 2010), as well as other applications that explored the thermal activation of urban tunnels as energy tunnels (Nicholson et al, 2014;Barla et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Energy performance and economic feasibility of energy segmental linings for subway tunnels

Cousin

Loria

Bourget³

et al. 2019

Tunnelling and Underground Space Technology

View full text Add to dashboard Cite

This study focuses on the analysis of the energy performance and economic feasibility of so-called tunnel energy segmental linings: an innovative technology that couples the structural support role of the tunnel lining with the heating-cooling role of the heat exchanger harvesting both shallow geothermal and aerothermal energies. The work is based on three-dimensional time-dependent thermo-hydraulic finite element analyses of a real case-study and presents a sensitivity investigation on the energy performance of energy segmental linings for a variation of the following design solutions: (i) pipe configuration, (ii) heat carrier fluid flow rate and (iii) pipe distance from the tunnel intrados. Selecting the smaller pipe diameter for a pipe layout perpendicular to the tunnel axis involves installing a configuration with the higher pipe length per segment and represents the optimal solution in terms of thermal power harvested per unit lining surface. Increasing the heat carrier fluid flow rate to increase the turbulence in pipes represents an effective approach to improve the energy performance, with a decreasing effectiveness for a successive increase of the heat carrier fluid flow rate. Decreasing the distance between the pipes from the tunnel intrados significantly improves the energy performance, with an increasing effectiveness for a successive increase of the heat carrier fluid flow rate. The previous design solutions markedly influence the capital investment and operation costs of thermal power plants resorting to energy tunnels. For the same site conditions but different design solutions, these plants may not be considered economically attractive, with the most profitable application that is not necessarily associated with the design involving the highest harvested thermal power via the geostructure. Based on the results of this research, energy segmental linings appear a breakthrough technology for the renewable energy supply of the built environment when properly analysed and designed.

show abstract

Section: Pipe Embedmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Energy performance and economic feasibility of energy segmental linings for subway tunnels

Cousin

Loria

Bourget³

et al. 2019

Tunnelling and Underground Space Technology

View full text Add to dashboard Cite

show abstract

“…A finite element thermal-mechanical model was developed using a multi-physics software to simulate the thermal performance of the TES system by analyzing how different heat extraction rates affect the temperature of the heat carrier fluid. The results showed that heat extraction rates are limited by the risk of fluid freezing and can reach up to 30 W/m 2 [38]. A similar system was proposed by [39], who numerically analyzed the feasibility of developing an energy tunnel in Turin.…”

Section: Waste Heat Recovery From Railway Tunnelsmentioning

confidence: 79%

“…A different design approach must be taken when dealing with underground rail systems built with mechanized tunneling. A design of railway tunnels with absorber pipes embedded within segments of the tunnel lining, namely the tunnel energy segment (TES) system, was analyzed by the authors of [38], who showed how cooling can be provided to the Crossrail tunnels in London while waste thermal energy is harvested to heat nearby buildings. A finite element thermal-mechanical model was developed using a multi-physics software to simulate the thermal performance of the TES system by analyzing how different heat extraction rates affect the temperature of the heat carrier fluid.…”

Section: Waste Heat Recovery From Railway Tunnelsmentioning

confidence: 99%

Opportunities for Integrating Underground Railways into Low Carbon Urban Energy Networks: A Review

et al. 2019

View full text Add to dashboard Cite

Cities demand vast amounts of energy for their everyday operation, resulting in significant degradation of energy in the form of heat in the urban environment. This leads to high cooling requirements in cities, while also presenting the opportunity to reuse such waste heat in order to provide low-carbon heating for buildings and processes. Among the many potential energy sources that could be exploited in urban areas, underground railway tunnels are particularly attractive, as the operation of the trains produce considerable amounts of heat throughout the year. This paper reviews how secondary energy sources in urban areas can be integrated into heating and cooling networks, with emphasis on underground rail tunnels. This involves investigating potential urban waste heat sources and the existing state-of-the-art technologies that could be applied to efficiently recover this secondary energy, as well as analyzing how district heating and cooling networks have been a key mechanism to allow for a smooth transition from current fossil fuel based to future low-carbon energy sources.

show abstract

“…The shallow ground surrounding an old overheated subway system thus has a large potential of low enthalpy energy that can be used for low-grade heating and cooling purposes. Advances in ground source heat pump configurations makes it possible to consider extracting this geothermal energy in an efficient manner (Nicholson et al 2014). Recent applications have shown successful integration of geothermal systems with underground tunnels using heat exchanger pipes in tunnel lining, such as in the Channel tunnel, Lainzer tunnels (Franzius and Pralle 2011), and Stuttgart Metro U6 (Schneider and Moormann 2010).…”

Section: Introductionmentioning

confidence: 99%

Multi-dimensional simulation of underground subway spaces coupled with geoenergy systems

Mortada

Choudhary

Soga

2018

Journal of Building Performance Simulation

View full text Add to dashboard Cite

Old and deep subway lines suffer from overheating problems, particularly during summer, which is detrimental for passenger comfort and health. Geothermal systems could serve as one of the potential energy efficient cooling solutions, compared to energy intensive conventional cooling. The waste heat of the subway tunnel can be harnessed, to provide heating to residential and commercial blocks above the tunnels. This paper presents a multi-scale co-simulation framework for quantifying the amount of useful heat that can be extracted from overheated underground subway tunnels using geothermal heat exchangers. The co-simulation is applied and tested on a representative section of the London Underground's Central Line. The Central Line is modelled using a 1D heat and mass transfer model. The geothermal system, on the other hand, is represented using a 3D finite element model. The 1-D and 3-D models are cosimulated, using the subway tunnel's outer wall temperatures as boundary conditions. The model is run parametrically to identify the best arrangement and depth of geothermal heat exchangers for extracting excess heat from subway tunnels. Results show that the depth of 15 m. below the tunnel is sufficient for vertical closed loop heat exchangers to yield temperature drop of 4 • C in the subway tunnel and platforms. Partially insulated boreholes, alternating between extracting and injecting heat into the soil, are also assessed for their potential to provide heating and cooling demand simultaneously and improve the overall geothermal system efficiency. The heat extracted along a representative section of the tunnels is compared to the heating demand of the buildings above ground.

show abstract

The design of thermal tunnel energy segments for Crossrail, UK

Cited by 41 publications

References 5 publications

Energy performance and economic feasibility of energy segmental linings for subway tunnels

Energy performance and economic feasibility of energy segmental linings for subway tunnels

Opportunities for Integrating Underground Railways into Low Carbon Urban Energy Networks: A Review

Multi-dimensional simulation of underground subway spaces coupled with geoenergy systems

Contact Info

Product

Resources

About