Document O3bKKqrpB5GnK7BY2V7eZqQgQ
HEATINC VENTILATING AIR CONDITIONING GUIDE 1940
sion systems are, also, equipped with A. C. motors for operation from auxiliary circuits. As these equipments can only be operated when con nected to the auxiliary circuit or while the train is running above the cut in speed of the drive, many cars are equipped with an auxiliary hold-over system by which reserve cooling is available. Due to the characteristics of the direct drive, the air conditioning system operates at reduced capac ity when the car is moving at speeds below 42 mph.
Table 2. Locomotive Power Demands for Different Air Conditioning Systems
System
Drawbar Horsepower per Car Required at Train Speeds
30 MPH 50 MPH | 70 MPH 90 MPH
For Continuous Operation
Electro Mechanical...... .......................................... Direct Mechanical.................................................. Internal Combustion Engine Mechanical____ Steam Ejector3........................................................ Ice-Activated._.........................................................
20.9 16.8 3.4
7.6 3.2
, 22.2 19.5 4.6 9.3,
4.5
25.4 29.5
7.0 12.5
6.8
31.6 42.6 11.9 19.0 11.6
For Non-Operation
Electro Mechanical-- .......................................... 5.0 6.4 9.0 14.4
Direct Mechanical.................................................. 5.2 6.3 8.7 13.5
Internal Combustion Engine Mechanical
2.2 3.5 5.8 10.6
Steam Ejector.......................................................... 3.7 5.4 8.4 14.8
Ice-Activated--......... ............................................. 1.9 3.2 5.5 10.2
For Average Condition of 56 Per Cent Continuous Operation and 44 Per Cent Non-Operation
Electro Mechanical................................i................ Direct Mechanical:......................................... ...... -Internal Combustion Engine Mechanical____ Steam Ejector......................................--..-- Ice-Activated............. 1i...*............ j........................
13.9 11.7
;2.8 5.9 ;2.6
15.2 13.7
4.1. 7.6 3.9
18.2 20.3
6.5: 10.7-
6.2
i
24.0 29.6 ! 11.4
: 17.5 ' 11.0
In addition, steam is required from .the locomotive to the extent of 230 lb per hour during the time the * equipment is in operation.
COST OF RAILWAY AIR CONDITIONING
The cost of railway air conditioning is usually expressed in terms of 1000 car-miles. The actual costs for the different systems, however, are dependent upon a number of variables. Based upon a survey of the most prominent railroads in air conditioning, arid upon extensive tests, the values given in Table 3 are indicative of the present costs of air con ditioning to, the railroads.
Gross Installation Cost
The gross installation cost, from which the fixed charges are derived, may be amortized on this basis:
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CHAPTER 33. RAILWAY AIR CONDITIONING
Table 3. Air Conditioning Costs for Railway Air Conditioning
System
Gross Installation
Cost
Electro Mechanical............ ..... Direct Mechanical__________ Internal Combustion
Engine Mechanical_____ Steam Ejector........................... Ice-Activated. ....................
$6,484.00 8,515.00
5,750.00 8,475.00 3,982.00
Fixed Charges
$ 8.65 11.35
7.67 11.30
5.31
Costs per 1000 car-miles*
Maintenance Cost
Operation Cost
$3.33 2.33
$0.99 0.93
3.30 2.15 0.97
1.99 1.02 5.29
Total
$12.97 14.61
12.96 14.47 11.57
For an average cooling season of 5 months, an average train speed of SO mph and an average car mileage of 150.000 miles per year.
1. Depreciation, at the rate of 12.5 per cent. 2. Interest, at the rate of 6 per cent. 3. Taxes and insurance, at the rate of 1.5 per cent.
The fixed charges per 1000 car-miles for any type of system are:
PC =
(0.20/1)
(1)
where
FC = fixed charges, dollars per 1000 car-miles. A -- gross installation cost, dollars, m = total number of car-miles traveled in one year.
Maintenance Cost
The average maintenance cost is based upon the experience of the railroads in maintaining several hundred air conditioning units. The maintenance cost per 1000 car-miles is:
where
MC = '-* m
MC = maintenance cost, dollars per 1000 car-miles. B = total annual maintenance cost, dollars.
m = total number of car-miles traveled in one year.
(2)
Operation Cost The cost of operation is influenced by:
1. Speed of train operation.
2. Average drawbar horsepower required to operate air conditioning-system.
3. Length of the cooling season.
. .. .
4. Cost of power produced by the locomotive at 80.00493 per horsepower-hour.
5. Proportion of time the cooling equipment is operated during the cooling season considered as 56 per cent.
6. Cost of additional necessities as: a. Ice in bunker, at $4.42 per ton, b. Propane on the car, at $0,039 per pound, c. Steam at $0,021 per 100 pound.
The operation cost in dollars per 1000 car-miles is:
OC=^(DX + 0.56RXG)+lM^(ffX)
125
125
593
(3)