Power supply to the laboratory

Contents

Contents

1. Regulatory and technical documents

2. Source Data

3. Calculation of air exchange according to the criterion of assimilation of harmful and explosive impurities in the charging room

4. Calculation of air exchange by the criterion of assimilation of heat inputs in the charging room in the warm period of the year

5. Calculation of air exchange according to the criterion of assimilation of heat inputs in the charging room in the cold period of the year

6. Conclusion

Regulatory and technical documents

The calculation was carried out on the basis of the TA from CJSC... "," and regulatory documents :

1.1. SNiP 04.05.91 * "Heating, ventilation and air conditioning" (Appendix 17),

1.2. Electrical Installation Rules, Sixth Edition, Supplemented, Moscow, Gosenergonador, 2000 (Chapter 4.4 Accumulator Plants, Item 4.4.40... 4.4.45),

1.3. SNiP II5875 Design Standards, Part II Thermal Power Plants, Glava58, Moscow 1976 (section 5 "Heating and ventilation," item 5.36... 5.41).

Due to the lack of technical documentation for traction batteries with unattended galvanic cells, instructions, descriptions and recommendations from the websites of specialized organizations engaged in the selection, supply and maintenance of traction batteries (hereinafter referred to as "AKB") with similar technical parameters were used for electric loaders of the Komatsu FB 15 (12) type:

1.4. Chemical Current Sources (Question - Answer);

1.5. SSK GROUP, supply of traction unattended sealed batteries of the PzV series from 2V to 172V by SSK, Belgium (description "SSK Energic Chargers for Traction Batteries," and Memo "Main Reasons for Reduced Service Life and Premature Failure of Traction Batteries");

1.6. ZAO "AkkuFertrib," supply of traction unattended sealed batteries of series EPzV and EPzV_BS company "EXIDE Technologies," Germany (Operating Manual 56025017 "Sonnenschein traction batteries of series EPzV and EPzVBS sealed fully unattended lead-acid batteries with tubular plates").

Source Data

2.1. Information was drawn from the Internet that for electric loaders of the Komatsu FB 15 (12) type, traction non-serviced AKBs with a voltage of V = 48V and a capacity of C5 = 438 Ah are used.

2.2. Two-stage charging mode with Wadiagram as per DIN 41774 (value of charging current is assumed as I = 0.2 C5) is used for charging of unserved automatic bombs (see [1.4] and [1.5]). The calculated value of the charging current is taken as I = 0.2 C5 = 90 A.

2.3. The voltage (EMF) of one electrochemical cell was assumed to be V = 2v (see [1.5] and [1.6]). In case of serial connection to obtain the common EMF 48b, the traction non-serviced sealed AKB must consist of 24 galvanic elements (hereinafter referred to as "elements").

2.4. According to the TA in room No. 30 with a charging area of ​ ​ 144 m2, 15 charging posts for traction actuators with a voltage of V = 48V and a capacity of C = 438 Ah will be located.

2.5. The consumed electric power of one charger (see [1.5]) during charging of the battery with voltage V = 48V and capacity C5 = 438 Ah is accepted equal to Npotr = 5 kW .

2.6. The calculation obtained that 19% of the consumed electricity in the physical and chemical charging process of the battery goes into heat (i.e. the process efficiency is 81%, see Appendix 2). Then the heat input from one charging station will be 0.97 kW. Accordingly, from 15 posts, the supply of heat will be 14.55 kW.

2.7. From the operating instructions (see [1.5] and [1.6]), the following temperature modes of operation and charging of traction non-serviceable automatic bombs were adopted:

- nominal temperature of unserved electrochemical cell T = + 30 ° С;

- during charging 910 hours the temperature of the battery rises by ∆T = 10... 15 ° С;

- maximum operating temperature of battery T = + 45 ° С;

- the maximum permissible temperature of galvanic elements of the unattended battery is T = + 55 ° С (at higher temperature there is a process of their melting and failure);

- minimum permissible air temperature in the charging room T = + 15 ° С (at a lower temperature it will not be possible to achieve the correct battery charge);

- maximum admissible air temperature in charging T = +40 °C;

- nominal air temperature in the charging room in the working zone T = + 16... 30 ° С;

- permissible (calculated) air temperature in the charging room in the upper zone + 35... 40 ° С.

2.8. Outside air parameters B (see [1.1]) for the city of Moscow were adopted for calculation:

- for cold period Tn.v. = 28 ° С, Jn.v. = 27.8 kJ/kg;

- for warm period Tn.v. = + 28.5 ° С, Jn.v. = + 54.0 kJ/kg.

2.9. To calculate, the supply air temperature was adopted:

- for cold period Tg = + 16 ° С,

- for warm period Tp. = + 28.5 ° С.

2.10. For calculation, the temperature of the removed air was adopted (80% exhaust from the upper zone) equal to Tv.  = + 38.5 ° С. I.e. the calculated temperature drop "inflow/exhaust" in the warm period of the year will be ∆TLt = 10 ° С, and in the cold period ∆TZm = 22.5 ° С.

2.11. The organization of the air exchange scheme was adopted: supply of supply air directly to the lower zone of the room (see paragraph 5.37 [1.3]) at a speed of not more than 2 m/s, and exhaust - from the lower zone of 20% and from the upper zone of 80% (see paragraph 4.4.43 [1.2]) - directly under the ceiling of the room.

2.12. In the warm period of the year, the supply air is not cooled and has an outside air temperature.

2.13. Below are two calculations of air exchange: according to the criterion of assimilation of harmful and explosive impurities in the charging room (sulfuric acid vapors and hydrogen; Hydrogen MPC is equal according to Appendix 17, SNiP 2.04.0591 * 10% of NPPRP, which corresponds to 4% for hydrogen) and according to the criterion of assimilation of heat wastes, i.e. - to maintain the internal air temperature in the working area of the room within the permissible limits. Then the determining air exchange is selected and the conclusion is made.

Conclusion

As can be seen from the above calculations of air exchange, the determining factor was thermal waste in the warm period of the year, and not the emerging harmful and explosive impurities. Cost reduction is not allowed due to overheating of galvanic elements of charging automatic bombs. And as can be seen from the temperature modes of operation and charging of the battery given in 2.6, unattended batteries do not tolerate overheating. During overheating, AKB lose their capacity or fail (the limit temperature of the elements is + 55 ° С).

Therefore, as a design in the warm period of the year, an air exchange was adopted for the calculation of assimilation of heat wastes for the warm period of the year (i.e. 4550 m3/h for inflow, and 5000 m3/h for exhaust).

In the cold period of the year, in order to maintain optimal air parameters and to save energy resources, air exchange was adopted for assimilation of harmful and explosive impurities (i.e. 2270 m3/h for inflow, and 2600 m3/h for exhaust).

To reduce cost, simplify automation and get the possibility of redundancy of fans of inflow and exhaust units for summer/winter modes, a scheme (1 + 1 )/1 was adopted.

For 100% redundancy of ventilation in order to ensure uninterrupted operation of the charging battery and to prevent increase of hydrogen concentration above MPC and above NCPRP (4% of the volume) in case of failure of ventilation, it is planned to put in the project a backup exhaust fan, i.e. in fact there are 3 exhaust fans (2 working and 1 standby).

Also, for emergency operation of the plenum ventilation plant in the warm period of the year, a normally closed fire valve should be provided in the internal partition of the charging room No. 30 (wall between the charging room and the warehouse). If one fan of the plenum ventilation unit fails, this valve must open automatically, and the amount of air removed by the exhaust ventilation system will be partially compensated by air flow from the warehouse.

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