Design of battery room ventilation using hydrogen concentration dilution method has been made easier with  aBattMV program - a small mobile software specially designed for engineers & designers.

Aim: creating a mobile design environment for the practising engineers & designers in today's mobile world.

Results: Instant solutions at your fingertips.

Highlights:

• battery room ventilation calculations

• by Hydrogen concentration dilution method in according to EN 50272-2 & EN 50272-3 Standards

• "Select  & Click" with built-in data like Igas, battery rated capacity, etc 

• louvre sizer

• in SI & IP units

see aBattMV explained.

Design Principles . . .  

The battery room ventilation is calculated in accordance to EN 50272-2 & EN 50272-3 Standards. The ventilation flow rate is calculated using the following formula:

Q = v * q * s * n * Igas * Cn / 100

where 

Q = ventilation air flow (CMH)

v = necessary hydrogen dilution factor (depends on % of air-hydrogen mixture)

q = hydrogen release rate, typically=0.00042 m3/Ah

s = safety factor, generally=5 for building projects

n = number of cells

Igas = current producing gas during charging (A/100Ah)

Cn = capacity of a battery (Ah). Note: This refers to rated ampere-hour capacity of lead acid or NiCd cell of the battery.

How to calculate ventilation requirements for a battery room?

Instant results at your fingertips on-the-move with  aBattMV   program.

Example (in English units)

A battery room (40 ft x 30 ft x 15 ft high) contains 10 batteries. Each battery has 18 cells. The rated capacity of the battery is 850 Ah. Boost charging method is employed for charging of battery. The hydrogen concentration in the room shall be kept below 1%. Find the hydrogen concentration in the room, and ventilation rate required.

Ignore the volume occupied by the battery.

Instant results   

Nos. of cell per battery = 18

Battery rated capacity (Ah) = 850

Nos. of battery = 10

Charging current (A/Ah) = 0.02

H2 release rate (ft³/h) = 0.01474

H2 produced (ft³/h) = 45.1044

Nett room vol (ft³) = 18000.00

% H2 after 1 hr (%) = 0.2506

Allowable H2 (%) = 1

Safety factor = 5

Airflow required (CFM) = 372.11

Room airchange/hr = 1.24

The following duct sizing result is calculated using aDuctulator program (to be purchased separately):

Retangular Duct sizing

Equal Friction method

==================

f.loss rate (in.wc/100') =0.1

Roughness (ft) =0.0003

Air volume (CFM) =372.11

Duct height (in) =6

Duct width (in) =13

Duct velocity (FPM) =697.9

detail results...........

Area, A (sq.ft) = 0.53

Relative roughness, e/Dh = 0.000441

Hydraulic diameter, Dh (in) = 8.2

Reynolds nos, Re = 48851

Friction factor, f = 0.022471

Velocity pressure, Pv (in.wg) = 0.030