Statistical Method to Define Rational Heat Loads on Railway Air Conditioning System for Changeable Climatic Conditions
Статистический метод определения рациональных тепловых нагрузок на железнодорожные системы кондиционирования воздуха при изменяющихся климатических условиях
2018-11-01
SCID: 54.1/68uyrd4g
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changeable climatic conditionsrailway air conditioningrational heat loadrefrigeration capacity productionstatistical method
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Abstract (AI)
A statistical method of defining rational heat loads on railway air conditioning system with taking into account the current changeable heat loads corresponding to current climatic conditions on the route lines has been proposed. According to this method the rational designed heat load on refrigeration machine, matching current changeable climatic conditions on the route lines and providing efficient operation of refrigeration machine of air conditioning system with maximum (close maximum) refrigeration capacity production (refrigeration output) for definite period of operation (monthly, seasonal or annular period) is defined through statistical treatment of data sets of hourly refrigeration capacities corresponding to the current climatic conditions on the route lines by their summation during the operation period for various installed (designed) refrigeration capacities of machine.The method is based on the hypothesis of different rates of refrigeration capacity production increment for the period of operation with increasing the installed refrigeration capacity, that is revealed in slowing down the rate of refrigeration capacity production increment at over increased installed refrigeration capacity. Proceeding from this hypothesis the rational value of heat load on railway air conditioning system is chosen close to the value that corresponds to the maximum refrigeration capacity production for the period of operation. Such rational value of designed heat load on railway air conditioning system provides reduction of refrigeration machine capacity and its cost by 15...20% as compared with traditional its designing for the maximum heat load. The operation of refrigeration machine in partial modes for enlarged installed refrigeration capacity chosen traditionally - for the maximum heat load needs application of expensive inventor compressors to control motor speed matching current changeable heat loads.
Key Findings
1
A statistical method was proposed to define rational heat loads for railway air conditioning by using hourly refrigeration capacity data summed over operation periods (monthly, seasonal, annual).
2
Choosing the rational designed heat load close to the value that maximizes refrigeration capacity production reduces required refrigeration machine capacity and cost by 15–20% versus traditional design for maximum heat load.
3
The approach is based on a hypothesis that refrigeration capacity production increment slows as installed refrigeration capacity increases, indicating diminishing returns at higher installed capacities.
4
The method matches designed refrigeration capacity to current, changeable climatic conditions on route lines, aiming to maximize refrigeration output over the chosen period.
5
Traditional oversized designs operate refrigeration machines in partial modes and require expensive inverter compressors for speed control, a need reduced by the proposed rational design.
Research Object
Railway air conditioning system (refrigeration machine and its installed/design heat load)
Research Subject
Statistical definition of a rational (optimized) designed heat load and corresponding installed refrigeration capacity based on hourly refrigeration-capacity data under variable climatic conditions to maximize refrigeration output over a chosen operation period and reduce installed capacity/cost
Publication Details
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2018-11-01
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