Safety in hazardous locations, interest in home fuel cells

Re: "Intrinsically safe or Explosion proof," Control Engineering North America edition, October 2008. As a regular user of both IS and EXD equipment for automotive spray applications (Class 1 Div. 1), it was nice to see an article about our forgotten needs. I would like to point out another important difference between IS and EXD other than costs: Maintenance.

04/01/2009


Re: "Intrinsically safe or Explosion proof," Control Engineering North America edition, October 2008.

As a regular user of both IS and EXD equipment for automotive spray applications (Class 1 Div. 1), it was nice to see an article about our forgotten needs. I would like to point out another important difference between IS and EXD other than costs: Maintenance.

EXD enclosures maintain their integrity by using lots and lots of bolts around the perimeter with torque specs. This leads to increased labor time to service equipment, leading to longer production downtimes when there are failures. Furthermore, many times the bolts are not all secured properly after a service, thereby making the enclosure no longer safe. I have actually seen bolt heads glued onto enclosures so the maintenance personnel would not have to work as hard. Scary as it may seem, it happens. With IS systems, this risk is eliminated and is one more reason to use them.

I am curious about the battery operated devices mentioned in the article. I hope they are certified for use in the environment they are putting them in. As you mentioned in the article, capacitance is a major factor in device selection. Just because a battery doesn't create a spark when you change it out, does not mean the unit has not built up a charge that could create a spark. It is important to note that both the intrinsic barrier and the device connected to it need to be third-party listed for use in the environment, with some exceptions for simple devices such as limit switches that cannot hold capacitance.

One more thing to mention. Purging and pressurization (NFPA 496) is another way in which motors can be deployed in hazardous areas. Here at FANUC Robotics America, our paint robots are purged with fresh air and maintained with a positive pressure inside. This allows the use of regular servo motors in hazardous areas.

Just wanted to put my two cents in. I am always on the lookout for ways to safely implement new controls technology in hazardous locations.

Matthew R. Carter, Senior Engineer - Controls Hardware, Paintshop Automation, FANUC Robotics America , www.fanucrobotics.com

Home fuel cell interest grows

Re: "Heat and power your home with a fuel cell," news item by Peter Welander, in which he describes Baxi Innotech's new Gamma 1.0 Fuel Cell Heating Unit.

I would love to put one in my home. It would have to have a break even on the financial return in less than 2 years. At 20,000 hours, it looks like the unit would only last slightly more than 2 years.

Bertram Barco, U.S. Engineer

Well, I hate to be critical, because I'm dying to get a fuel cell mCHP system in my house, but Ballard Power, the world's largest producer of PEM fuel cells, is located in Vancouver, British Columbia, Canada.

In regard to the more mundane details, the Ballard 1030 stack has achieved 40,000 hours in lab tests with previous versions (at 8–12 hours/day, this is a hard benchmark to achieve in the field). Field tests include hundreds installed by Tokyo Gas over the past 4 years. BAXI is one of the largest heating system manufacturers in Europe and knows what they're doing. On the other hand, the EU, Germany, and the UK have much morestringent environmental requirements than the US, and multiple well-funded programs to promote fuel cell commercialization in general and FC mCHP in particular.

As far as low temp (&100 °C) PEM FC technology, that is perhaps the least practical of the fuel cell technologies being used for these applications, but far and away the most reliable. HT PEM at 160–200 °C provides high quality, which can be used to run cooling systems in the summer. They are less demanding on the fuel supply where hydrogen must be reformed from natural gas, making for simpler and potentially much cheaper systems. Solid Oxide Fuel Cells (SOFC) operate at 500 °C –1000 °C, have a much higher power to heat ratio, are self-reforming (can use NG, LPG, or even biogas directly at high temps), and need no platinum catalyst at all, therefore being potentially near the cost as simple home heating systems. 1.5 kW – 3 kW (for the power hungry US market) of power is the target for these, but 1 kW will do because of the incredible efficiency, silent operation, and lack of pollutants given off by the non-combustive devices.

Jim Horwitz, industry analyst, Newton, MA , FuelCellIntel@comcast.com





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