This document discusses ecologic solutions for urban transit systems. It addresses two main concerns: energy savings and reducing heat evacuation from systems onboard trains. For air conditioning systems, it proposes using an air-air exchanger to lower the needed capacity and save energy. For braking resistors, which waste energy as heat, it suggests using super capacitors to store braking energy instead of dissipating it as heat. The document analyzes the air conditioning and braking systems of trains and light rail vehicles in detail.

1. ECOLOGIC SOLUTIONS FOR URBAN TRANSIT
SYSTEMS
Hala Mohtasseb
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2. SUMMARY
1- URBAN TRANSIT SYSTEMS THE SOLUTION FOR TRAFFIC CONGESTION
2- CONCERNS RELATED TO URBAN TRANSIT SYSTEMS
 ENERGY SAVING
 HEAT EVACUATION
3-MAIN SYSTEMS ONBOARD THE TRAIN INVOLVED
4-AIR CONDITIONING SYSTEM
 AIR-AIR EXCHANGER SOLUTION
5- BRAKING RESISTOR
 ‘SUPER CAPACITORS ‘ SOLUTION
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3. URBAN TRANSIT SYSTEMS
THE SOLUTION FOR TRAFFIC CONGESTION
TRAFFIC CONGESTION
MORE AND MORE TRAFFIC CONGESTION
 INCREASE OF CO2 EMISSION
 NEED TO FIND A TRANSPORTATION SOLUTION TO MINIMIZE CO2 EMISION
URBAN TRANSIT SYSTEMS ( METRO AND LRT VEHICLES) IS THE
SOLUTION !
FULLY ELECTRICAL SOLUTION
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4. CONCERNS RELATED
TO TRANSIT URBAN SYSTEMS
CONCERNS RELATED TO URBAN TRANSIT SYSTEMS
THOUGH NUMBER OF METRO & LRT TRAINS WORLDWIDE IS
CONTINOULSLY INCREASING , SOME CONCERNS REMAIN UNSOLVED :
1-ENERGY SAVINGS
DAILY CONCERN FOR EUROPEAN COUNTRIES
2-REDUCTION OF HEAT EVACUATED BY SYSTEMS ONBORAD THE TRAIN
CONCERN EXPRESSED BY COUNTRIES WITH HIGH TEMPERATURES
 ESPECIFICALLY GULF COUNTRIES
SOLUTIONS TO COVER BOTH CONCERNS
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5. CONCERNS RELATED TO
TRANSIT URBAN SYSTEMS
MAIN EQUIPEMENTS ONBOARD URBAN TRANSIT SYSTEMS
METRO SYSTEM
AIR CONDITIONING
.
BOGIE
BRAKING RESISTOR TRACTION SYSTEM
BRAKE SHOES
BRAKING SYSTEM
MOTORS
AUXILIRAY INVERTES
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6. CONCERNS RELATED
TO TRANSIT URBAN SYSTEMS
MAIN EQUIPEMENTS ONBOARD URBAN TRANSIT SYSTEMS
LRT SYSTEMS AIR CONDITIONING
BRAKING RESISTOR
TRACTION SYSTEM
. BRAKING SYSTEM
AUXILIARY INVERTER
BOGIE
BRAKING SHOES
MOTORS
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7. CONCERNS RELATED
TO TRANSIT URBAN SYSTEMS
ENERGY SAVING TOPIC
EQUIPEMENTS ONBOARD WITH HIGHEST ENERGY CONSUMPTION
1-TRACTION SYSTEM
TO ENSURE DYNAMIC PERFORMANCE REQUESTED
2-AIR CONDITIONING SYSTEM
HEAT EVACUATION TOPIC
TOTAL HEAT DISSIPACTION IS MOSTLY DUE TO BRAKING RESISTOR SYSTEM
FIND NEW ECOLOGIC SOLUTIONS FOR AIR CONDITIONING SYSTEM
AND BRAKING RESISTOR SYSTEM
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8. AIR CONDITIONING SYSTEM
CALCULATION OF AIR CONDITIONING SYSTEM CAPACITY
TWO POSSIBILITIES
1- FOLLOWING RECOMMENDATIONS OF EUROPEAN STANDARD EN 14750 -1
“Air conditioning for urban and suburban rolling stock – comfort parameters“
COUNTRIES ARE CLASSIFIED BY ZONES ;
FOR FIXED EXTERIOR PARAMETERS REPRESENTING MOST SEVERE CONDITIONS
(Temperature , humidity , solar load )
 MAXIMUM INTERIOR TEMPERATURE RECOMMENDED BY THE STANDARD EN
14750-1 SHALL NOT BE EXCEEDED
CALCULATION OF THE AIR CONDITIONING SYSTEM CAPACITY NEEDED ,
WITH RESPECT OF STANDARD EN 14750-1 RECOMMENDATIONS
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9. AIR CONDITIONING SYSTEM
Zone(summer) Maximum ext temper Relative humidity
I + 40 40 %
II + 35 50%
III + 28 45%
Maximum mean interior temperature at the design condition °C
Zone Categ A Categ B category A : fresh air flow rate between 10 and 15 m3/h/passenger
I + 30 + 32 category B : fresh air flow rate between 8 and 12 m3/h/passenger
II + 30 + 33
III + 26 + 29
Country Summer
Austria Zone II
Belgium Zone II
France Zone II
Greece Zone I
Germany Zone II
Italy Zone I
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10. AIR CONDITIONING SYSTEM
CALCULATION OF AIR CONDITIONING SYSTEM CAPACITY
2-FOLLOWING CLIENT REQUIRMENTS IN TENDER DOCUMENTS
THIS APPLIES TO COUNTRIES NOT REFERRED IN STANDARD EN 14750-1
THIS APPLIES TO GULF COUNTRIES
DUBAI METRO / RTA REQUIREMENTS IN TENDER DOCUMENTS
Long Term Climate Information Book 2001 (dpt of Civil Aviation of Dubai):
From 1984 until 2001 the maximum temperature is 47.5°C 23%.
- Data from the Dubai airport (detailed data for year 2003).
Maximum temperature in 2003 was 46°C 10%
The system must work at 52°C 10%RH with an internal temperature of 27°C.
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11. AIR CONDITIONING SYSTEM
CALCULATION OF AIR CONDITIONING SYSTEM CAPACITY
DUBAI EL SAFOUH TRAMWAY / RTA REQUIREMENTS IN TENDER DOCUMENTS
The outside conditions to be considered in the design are the following:
 Dry bulb temperature: 47°C
For the other conditions, refer to Appendix B attached to the General Specifications (Annual
Climate and weather in Dubai).,
The A/C shall maintain a temperature of less than 25°C during at least 95% of the
operation time in Dubai, at 4 passengers/m2.
The tripping value for A/C above 53oC is guaranteed (maximum value 54 oC).
=> Difference of temperature of 22°C requested between the interior and
exterior
 High capacity needed for the Air conditioning system to comply with
above requirements
 HIGHER IS THE CAPACITY HIGHER WILL BE ENERGY CONSUMPTION
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12. AIR CONDITIONING SYSTEM
REDUCTION OF ENERGY CONSUMPTION DUE TO AIR CONDITIONING SYSTEM
 REDUCTION OF AIR CONDITIONING CAPACITY
 REDUCTION OF DIFFERENCE BETWEEN THE EXTERIOR TEMPERATURE AND
INTERIOR TEMPERATURE
 REDUCTION OF AIR INLET TEMPERATURE
SOLUTION :
AIR CONDITIONING SYSTEM + AIR-AIR EXCHANGER SYSTEM
AIR-AIR EXCHANGER ROOF MOUNTED TO BE INSTALLED NEXT TO THE AIR
CONDIONNING SYSTEM
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13. AIR CONDITIONING SYSTEM
AIR-AIR EXCHANGER SOLUTION
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14. AIR CONDITIONING SYSTEM
AIR-AIR EXCHANGER SOLUTION
ADVANTAGES OF AIR CONDITIONING + AIR-AIR EXCHANGER :
1-ENERGY SAVING ( LOWER CAPACITY NEEDED FOR AIR CONDITIONING)
3- MTBF DECREASED FOR AIR CONDITIONING SYSTEM
 TEMPERATURE OF AIR INLET WILL REMAIN LOWER THAN 40°C
 NO AIR CONDITIONING FAILURES DUE TO HIGH TEMPERATURES
2-TOTAL WEIGHT SAVING LEADING TO ADDITIONAL ENERGY SAVINGS
 WEIGHT DECREASED FOR AIR CONDITIONING SYSTEM
 WEIGHT DECREASED FOR AUXILIARY INVERTER
( system that provides necessary current to onboard equipment)
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15. BRAKING RESISTOR
USE OF BRAKING RESISTOR
TRAIN BRAKING PROCESS BY PRIORITY ORDER :
1- REGENERATIVE BRAKING
MAINLY ELECTRICAL BRAKING (complemented by mechanical braking at low speeds)
Braking energy is regenerated to the line ( voltage 1500 Vd or 750 Vdc)
 provides energy to the train behind .
 Total energy saving
1500Vdc
REGENERATIVE BRAKING PROCESS
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16. BRAKING RESISTOR
USE OF BRAKING RESISTOR
TRAIN BRAKING PROCESS BY PRIORITY ORDER
2-HEAT EVACUATION THROUGH BRAKING RESISTOR
WHEN THE LINE IS NOT RECEPTIVE
( case where there is no trains behind to receive energy )
 ENERGY MUST BE EVACUATED
 ENERGY TO BE SEND TO ONBOARD TRAIN BRAKING RESISTORS
 BRAKING RESISTOR WILL EVACUATE ENERGY BY PRODUCING HEAT
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17. BRAKING RESISTOR
DISADVANTAGES OF BRAKING RESISTOR
AT TRAIN LEVEL
 IMPORTANT INCREASE OF AIR TEMPERATURES AT BRAKING RESISTOR
LOCATION
 ENERGY WASTE
 HIGH WEIGHT OF BRAKING RESISTORS
WHEN THE TRAIN RUNS IN A TUNNEL
TUNNEL TO BE EQUIPPPED WITH ADEQUATE VENTILATORS
THERMODYNAMIC STUDY IS A MOST TO DETECT MOST CRITICAL
AREAS AT TRAIN LEVEL AND IN TUNNEL
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18. BRAKING RESISTOR
SUPER CAPACITORS SOLUTION
TO COVER ABOVE ISSUES SUPER CAPACITORS IS THE SOLUTION !
 ENERGY STORAGE
ENERGY STORED COULD BE USED TO SUPPLY OTHER EQUIPMENTS
ONBOARD THE TRAIN
 LOW WEIGHT
 VERY HIGH RATES OF CHARGE AND DISCHARGE
 IMPROVED SAFETY BY LOW TOXICITY OF MATERIAL
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19. THANK YOU !
Hala Mohtasseb
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