The Convection H2 Vent™

The Convection H2 Vent consists of two tube openings at the top of one side of the Cool Cell™. These openings are at the same level, a few inches apart, and of the same diameter. The rear tube extends through the sidewall to the opposite side of the enclosure, and then drops to within a few inches of the floor of the Cool Cell™. The adjacent forward tube extends only a few inches into the Cool Cell™.

The exterior of the openings is fitted with wind and rain guards, and with heavy-duty mesh to prevent intrusion by large insects or other animals. There is nothing to impede the flow of air into or out of the H2 Vent tubes.

Front View

This patented ventilation design allows hydrogen to easily escape from the Cool Cell™. Hydrogen rich air is buoyant; it rises. When hydrogen is released by the batteries, it mixes and hydrogen rich air finds its way to the short tube opening, and escapes to the outside. Fresh air is drawn into the rear tube opening, through the horizontal heat exchanger, down the dip tube to the bottom of the Cool Cell™.

Top View

The Convection H2 Vent maintains hydrogen concentrations at or below 85% of the lower explosive limit when hydrogen is introduced into a Cool Cell™ at the rate of 200 ml per minute per 48 volt, 125 ampere hour string of VRLA batteries. As hydrogen generation increases, the convection rate accelerates, which in turn reduces the concentration to a steady state flow below the lower explosive limit. As the Cool Cell™ is scaled up for larger battery complements, the Convection H2 Vent is scaled up accordingly.

Side View

The horizontal placement of the Convection H2 Vent openings virtually eliminates thermal convection. Comparative tests have shown that the Convection H2 Vent lowers the cooling efficiency of the Cool Cell™ by less than 2 deg. F. The safety assurance provided by the Convection H2 Vent is well worth the small loss of cooling efficiency.

Passive Design - The Ultimate in Reliability

Both the Convection and Diffusion H2 Vents are completely passive in design. This results in the highest degree of reliability, a critical specification in this safety related application. Simply put, if hydrogen becomes present in a Cool Cell™ equipped with either of our H2 Vents, it will escape.

At Zomeworks, our philosophy is to accomplish a task with no external power or moving parts wherever possible. Cool Cells™ are outdoor enclosures, and must be able to function in a wide variety of hostile environments. By keeping our designs simple, our products can operate reliably across a wide range of environmental parameters.

* U.S. Patent # 5660587 – Convection H2 Vent
* U.S. Patent # 5603656 – Diffusion H2 Vent