GB2404245A - Method for cooling an underground rail network - Google Patents
Method for cooling an underground rail network Download PDFInfo
- Publication number
- GB2404245A GB2404245A GB0321738A GB0321738A GB2404245A GB 2404245 A GB2404245 A GB 2404245A GB 0321738 A GB0321738 A GB 0321738A GB 0321738 A GB0321738 A GB 0321738A GB 2404245 A GB2404245 A GB 2404245A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tunnels
- network
- fans
- cooling
- air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000001816 cooling Methods 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims abstract description 16
- 238000005096 rolling process Methods 0.000 claims abstract description 11
- 238000011144 upstream manufacturing Methods 0.000 claims description 3
- 238000007664 blowing Methods 0.000 claims description 2
- 238000007599 discharging Methods 0.000 abstract description 3
- 238000005094 computer simulation Methods 0.000 abstract description 2
- 238000012546 transfer Methods 0.000 abstract description 2
- 239000000428 dust Substances 0.000 description 5
- 238000013021 overheating Methods 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 238000002791 soaking Methods 0.000 description 3
- 241000272470 Circus Species 0.000 description 2
- 238000004378 air conditioning Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000005338 heat storage Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F1/00—Ventilation of mines or tunnels; Distribution of ventilating currents
- E21F1/003—Ventilation of traffic tunnels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61D—BODY DETAILS OR KINDS OF RAILWAY VEHICLES
- B61D15/00—Other railway vehicles, e.g. scaffold cars; Adaptations of vehicles for use on railways
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61K—AUXILIARY EQUIPMENT SPECIALLY ADAPTED FOR RAILWAYS, NOT OTHERWISE PROVIDED FOR
- B61K13/00—Other auxiliaries or accessories for railways
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Transportation (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Ventilation (AREA)
Abstract
A method for cooling an underground rail network comprises after the rail service is shut down, temporarily positioning fans 10 mounted on rolling stock 20 across tunnels in the network so that cool air is drawn in via surface entrances of train stations 50 and flows through the tunnels to remove heat from walls 30 of the tunnels and expelling warm air from the tunnels via surface entrances of other train stations 60 downstream of the fans 10. The fans 10 may be of a size to fit the cross section of the tunnel. Turbulence vanes (12, fig 3) on rolling stock (22) may be temporarily positioned at intervals along the tunnels to increase the rate of heat transfer from the walls 30. Train stations 60 are preferably at an interchange of two or more tunnels and are larger than train stations 50 and enable large volume discharging of air without restricting flow. A computer simulation may be used to model the required cooling so that effective planning of scheduling the position of the fans, air volume flow, running time, length of tunnel to be cooled and quantity of heat removed.
Description
METHOD FOR COOLING AN UNDERGROUND RAIL NETWORK
Field of the invention
s The invention relates to a method to reduce overheating of an underground rail network (e.g. the London Underground) for the comfort and safety of the travelling public.
Background of the invention
Known methods are aimed at cooling the air felt immediately by the passengers. However, installing air conditioning units in the train carriages is not effective in cooling the underground network itself because the heat generated by the air conditioning units are rejected directly back inside the network. Ventilating the tunnels by forced air exchange at the train stations is inadequate because of the low air velocity that is permissible for the safety and comfort of people in the station. Using heat so storage units on the trains to absorb heat from the air and transport the heat to be discharged at the outskirt stations is inefficient and uneconomical because of the limited size of the heat storage units and the extra weight and space required on the trains. Such known solutions are not effective because they are in reality small measures which are inadequate to match the scale of the task required in relation with the size of the underground rail network.
Summary of the invention
In order to mitigate at least some of the above problems, there is provided according to the present invention a method for cooling an underground rail network wherein during the night period after the rail service is shut down when the tunnels are empty of trains and the stations empty of the travelling public, large fans mounted on rolling stock are positioned temporarily at predetermined - 2 locations across selected tunnels in the network for drawing cool air from above ground into the network via the surface entrances to the train stations upstream of the fans, causing the air to flow through the tunnels thereby removing heat from the walls of the tunnels, and expelling the warmed air out of the network via the surface entrances to other train stations downstream of the fans. This is off-peak cooling of the network in a large scale.
lo The invention is predicated upon the realisation that the root cause of the problem of overheating lies in the continuous soaking of heat into the walls of the tunnels in the network. This heat is generated by the trains and by the passengers at an annual energy loading estimated by the London Underground at around 650 GWhrs, a large proportion of which is absorbed deep inside the rocks and earth surrounding the tunnels, accumulated through time, increasing the temperature of the walls and causing the soaked air temperature within the network to become so uncomfortably hot. As the equilibrium temperature of the walls is creeping upwards relentlessly year after year, the fundamental solution for keeping the network cool lies in removing the heat that has accumulated. The best time to do this, in a scale large enough to match the huge magnitude that is required, is when the network is empty.
Simple calculations show that the amount of heat absorbed into the walls and surrounding earth is enormous to raise the temperature of the wall by just 1 C. If this heat could be removed so that the temperature of the walls is lowered by 5 C or 10 C and if this cooler temperature could be maintained by large scale cooling every night, the cooled walls would conversely become an enormous heat sink, capable of soaking up a huge quantity of heat during the day but increasing in temperature only slightly as a result. This will keep the network cool throughout the day in the same way as a natural underground cavern is cool all year round. 3 -
However, because so much heat is already absorbed into the walls of the tunnels, it would take many weeks and a lot of high speed large scale cooling every night to gradually bring the equilibrium temperature of the network to the desired level. Once that temperature has been reached, it would be routine cooling every night to maintain it, and the network will stay cool from then on.
In the invention, because the fans are used only after the rail network is shut down, each fan can be made very large to fit the cross-section of the tunnel and positioned at a temporary location where the tunnel narrows to fit the fan, thus creating a wind tunnel and producing a large scale high speed air flow in one direction through the tunnel.
Also because there will be no people in the train stations, a much higher wind speed will be permissible through the surface entrances of the stations where the air is drawn into or expelled out of the network. Thus the proposed method may be designed with the maximum effectiveness for so high speed large scale cooling, removing more heat in less time than could be done before, and bypassing many of the constraints that are normally imposed during daytime when the rail network is running.
In the invention, as the temperature of the cooling air in the tunnel increases and approaches the temperature of the walls of the tunnel, the efficiency of large scale heat removal will start to diminish. It is therefore important to select sections of the network by areas to be cooled, so such that the air forced through the network is expelled out of the network before it reaches a temperature approaching the temperature of the walls in that section.
A preferred way to do this is to select a train station at the interchange of two or more tunnels to serve as a node for expelling air out of the network drawn from other surrounding train stations within a catchment area connected - 4 - to the node. This will be efficient because the node interchange station is usually a larger station with many exits thus capable of discharging a large volume of air without restricting the flow. In this way, the entire network may be cooled efficiently by selecting a relatively small number of nodes each with an associated catchment area positioned strategically within the network. Furthermore the whole system is flexible and may be reconfigured differently each night to suit various maintenance schedules within the network.
Using the London Underground rail network as an example, the stations at Bank, King's Cross, Baker Street, Green Park, Oxford Circus, Liverpool street and Waterloo could be suitable nodes. Of course during the period when the rail service is in operation, the fans would be removed off the mainline track to allow free movement of the trains.
The large scale high speed cooling also has other important benefits of automatically flushing the network of dust and suspended particles and refreshing the air every night. Dust filters mounted with the fans on rolling stock; could be used to collect the dust as the air is drawn through the fans.
The running cost and the staging time to set-up and take-down the system would be small, since the fans are carried on rolling stock and could be towed as a train convoy and deployed (anchored) one by one at predetermined so points along the track in one trip for each line. Another trip later in reverse order will collect the fans again as a train convoy and park them out of the way of the mainline traffic. The fans may be switched on wherever they are by taking power either from the existing electric rail along the track or connected to the mains supply accessible from the train stations, and the whole system run by remote control. Finally the capital cost of implementing the - 5 - proposed method will be low and the disruption to the intra- structure or travelling public will be minimal.
Brief description of the drawing
The invention will now be described further by way of example with reference to the accompanying drawings in which Figure 1 is a schematic view of an underground rail network implementing the cooling method, lo Figure 2 is a schematic view of a fan carried on rolling stock, and Figure 3 is a schematic view of a turbulence inducing flow deflector carried on rolling stock.
Detailed description of the preferred embodiment
Figure 1 shows a schematic view of an underground rail network with train stations shown in circles 50 and interchange stations shown in double circles 60. Large fans so 10 positioned across selected tunnels are also shown in dark triangles pointing in the direction of air flow.
In Figure 1, during the night period after the rail service is shut down when the tunnels are empty of trains and the stations empty of the travailing public, the fans 10 mounted on rolling stock 20 (as shown in Figure 2) are positioned temporarily at predetermined locations across selected tunnels in the network. The fans 10 draw cool air from above ground into the network via the surface entrances to the train stations 50 upstream of the fans, then force the air to flow through the tunnels thereby remove heat from the walls of the tunnels, and finally expel the warmed air out of the network via the surface entrances to other train stations 60 downstream of the fans.
The invention is predicated upon the realization that the root cause of the problem of overheating within the - 6 network lies in the continuous soaking of heat into the: walls 30 of the tunnels in the network (as shown in Figures 2 and 3). This heat is generated by the trains and by the passengers and is absorbed deep inside the rocks and earth surrounding the tunnels, accumulated through time, increasing the temperature of the walls 30 and causing the soaked air temperature within the network to become uncomfortably hot. As the equilibrium temperature of the walls is creeping upwards relentlessly year after year, the lo fundamental solution for keeping the network cool lies in removing the heat that has been accumulated, and the best time to do this, in a scale large enough to match the huge magnitude that is required, is when the network is empty.
In the present invention, by implementing the method of large scale cooling whereby the heat stored within the walls is removed and rejected to the outside of the network efficiently and regularly during each night when the trains are not running, the thermal equilibrium will gradually change and the temperature of the walls and surrounding earth will slowly decrease. This will in turn influence the soaked air temperature within the network and keep it cool throughout the day in all sections of the network including tunnels, platforms and interchanges.
Because the fans are used only after the rail network is shut down, each fan 10 can be made very large to fit the cross-section of the tunnel (as shown in Figure 2) and positioned at a temporary location where the tunnel narrows so to fit the fan, thus creating a wind tunnel and producing a large scale high speed air flow in one direction through the tunnel. Also because there will be no people in the train stations, a much higher wind speed will be permissible through the surface entrances of the stations where the air iS drawn into or expelled out of the network. Thus the proposed method may be designed with the maximum effectiveness for high speed large scale cooling, removing more heat in less time than could be done before, and bypassing many of the constraints that are normally imposed during daytime when the rail network is running.
To further improve the efficiency of high speed heat removal, turbulence inducing vanes 12 mounted on rolling stock 22 (as shown in Figure 3) may also be positioned temporarily at intervals along the tunnels for increasing the rate of heat transfer from the walls along the tunnels.
In the invention, as the temperature of the cooling air in the tunnel increases and approaches the temperature of the walls 30 of the tunnel, the efficiency of large scale heat removal will start to diminish. It is therefore important to select sections of the network by areas to be cooled, such that the air forced through the network is expelled out of the network before it reaches a temperature approaching the temperature of the walls in that section.
so In Figure 1, a preferred section includes a train station 60 at the interchange of two or more tunnels serving as a node for expelling air out of the network drawn from other surrounding train stations 50 within a catchment area (shown within the chain-line circle) connected to the node.
This will be efficient because the node interchange station is usually a larger station with many exits thus capable of discharging a large volume of air without restricting the flow. In this way, the entire network may be cooled efficiently by selecting a relatively small number of nodes so 60 each with an associated catchment area positioned strategically within the network. Furthermore the whole system is flexible and may be reconfigured differently to suit different maintenance schedules within the network.
Using the London Underground rail network as an example, the stations at Bank, King's Cross, Baker Street, Green Park, Oxford Circus, Liverpool street and Waterloo - 8 - could be suitable nodes. Of course during the period when the rail service is in operation, the fans 10 would be removed off the mainline track to allow free movement of trains through the network.
The aim of the invention is to re-dress the thermal; equilibrium in the balance between heat input to the network and heat output (removal) from the network. Quoting London Underground's own estimate of an annual energy input of lo around 650 GWhr into the network, this heat has to go somewhere, if it is not removed externally, then it must inevitable be absorbed internally into the surrounding walls and rocks of the tunnel and shift the equilibrium temperature upwards. To get this heat out of the walls, the cooling must be in a scale large enough to reverse the upward trend, then, it would only be a matter of time to see the desired result.
The important parameter of the invention is therefore the volume of air that is needed to reverse the upward trend in the thermal equilibrium. The proposal of performing the cooling at night after the rail service is shut down allows the maximum throughput of air in an empty wind tunnel thus achieving high wind speeds and efficient cooling. Also night air will be cooler and more effective.
It is not necessary to carry out the cooling everywhere in the network every night, but as long as some part of the network is cooled some nights, and this is done diligently so with proper planning in rotation, the cumulative effect will soon become evident and the average equilibrium temperature will start to fall. So the cooling schedule could be carried out in different parts of the network at different times and planned so that it does not interfere with the engineering work schedule. The fans may be switched on wherever they are by taking power either from the existing electric rail along the track or connected to the surface 9 mains supply accessible from the train stations, and the whole system may be run by remote control.
The simplest case will be two fans blowing from opposite directions towards a node station, each positioned at an adjacent station extracting surface air and forcing it out in the middle at the node, thus cooling the tunnel in between. The strong wind will be felt at the node and adjacent stations but will get weaker at the further stations, thus will not affect engineering work further away along the line. The fans may be moved up and down the line to different sets of stations to cool the line section by section. Dust filters mounted with the fans on rolling stock could also be used to collect dust as the air is drawn through the fans.
A computer simulation may be used to model the thermal equilibrium. Assuming a realistic cooling schedule, it is possible to simulate the soak temperature of the air in the tunnel through a 24 hour cycle including all the heat inputs and outputs at different times during the 24 hours, and show a nett reduction (small, but in the right direction) which in time will gradually bring about a noticeable drop in temperature.
Once the 24 hour cycle model is developed and validated, it could become a flexible and effective planning tool for scheduling the cooling across the network and directing the day-to-day operation in order to maintain a stable cool temperature within the network, e.g. where to position the fans, how much the air volume flow, how long the running time, what length of tunnel is cooled, how much heat is removed, how is the equilibrium temperature changed, how the cooling schedule is rotated to different parts of the network, how to sustain the new equilibrium continuously in the future etc. - 10
Claims (6)
1. A method for cooling an underground rail network wherein during the night period after the rail service is shut down when the tunnels are empty of trains and the stations empty of the travelling public, large fans mounted; on rolling stock are positioned temporarily at predetermined locations across selected tunnels in the network for drawing cool air from above ground into the network via the surface lo entrances to the train stations along the tunnels upstream of the fans, causing the air to flow through the tunnels thereby removing heat from the walls of the tunnels, and expelling the warmed air out of the network via the surface entrances to other train stations along the tunnels downstream of the fans.
2. A method of cooling an underground rail network as claimed in claim 1, wherein the fans are positioned near adjacent stations around a node station for drawing surface air from the adjacent stations, blowing the air through the tunnels in converging directions towards the node station thereby removing heat from the walls of the tunnels, and expelling the warmed air out of the node station.
3. A method of cooling an underground rail network as claimed in claim 2, wherein the node station is a train station at an intermediate point along a tunnel.
4. A method of cooling an underground rail network as claimed in claim 2, wherein the node station is a train station at the interchange of two or more tunnels.
5. A method for cooling an underground rail network as claimed in any preceding claim, wherein each fan is sufficiently large to fit the crosssection of the tunnel at the temporary location thus creating a wind tunnel and producing a high speed air flow through the tunnel. - 11
6. A method for cooling an underground rail network as claimed in any preceding claim, wherein during the period when the rail service is in operation, the fans are removed off the mainline track to allow free movement of trains through the network.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0317094A GB0317094D0 (en) | 2003-07-22 | 2003-07-22 | Method for cooling an underground rail network |
| GB0320669A GB0320669D0 (en) | 2003-07-22 | 2003-09-04 | Method for cooling an underground rail network |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0321738D0 GB0321738D0 (en) | 2003-10-15 |
| GB2404245A true GB2404245A (en) | 2005-01-26 |
Family
ID=29252472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0321738A Withdrawn GB2404245A (en) | 2003-07-22 | 2003-09-17 | Method for cooling an underground rail network |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2404245A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2470974A (en) * | 2010-02-01 | 2010-12-15 | M I E Services Ltd | Underground railway tunnel ventilation apparatus |
| EP3339128A1 (en) | 2016-12-22 | 2018-06-27 | Mitsubishi Electric Corporation | Direct expansion air-conditioning unit for cooling a tunnel |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1001214A5 (en) * | 1988-07-20 | 1989-08-22 | Air Chaleur Sa | Cooling system for road or rail tunnel atmosphere - comprises wheeled vehicle carrying cooling plant which operates as it travels through tunnel |
| JPH1130099A (en) * | 1997-07-14 | 1999-02-02 | Taisei Corp | Ventilation constitution and method for working circumstances in existing tunnel |
| US6336594B1 (en) * | 1997-10-22 | 2002-01-08 | Jurgen Bader | Large scale positive pressure ventilation machine |
-
2003
- 2003-09-17 GB GB0321738A patent/GB2404245A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1001214A5 (en) * | 1988-07-20 | 1989-08-22 | Air Chaleur Sa | Cooling system for road or rail tunnel atmosphere - comprises wheeled vehicle carrying cooling plant which operates as it travels through tunnel |
| JPH1130099A (en) * | 1997-07-14 | 1999-02-02 | Taisei Corp | Ventilation constitution and method for working circumstances in existing tunnel |
| US6336594B1 (en) * | 1997-10-22 | 2002-01-08 | Jurgen Bader | Large scale positive pressure ventilation machine |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2470974A (en) * | 2010-02-01 | 2010-12-15 | M I E Services Ltd | Underground railway tunnel ventilation apparatus |
| GB2470974B (en) * | 2010-02-01 | 2011-11-16 | Mechanical & Internal Environmental Services Ltd | Underground railway tunnel ventilation for single line tunnels |
| EP3339128A1 (en) | 2016-12-22 | 2018-06-27 | Mitsubishi Electric Corporation | Direct expansion air-conditioning unit for cooling a tunnel |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0321738D0 (en) | 2003-10-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |