Introduction
Modern day problems require modern day solutions,
and one of the current problems facing IT Managers is how to guarantee
server room resilience, in the event of a long power outage, when there
is no room on site for a standby generator. With the ever increasing
height of office buildings, and the crowded city environment, trying to
find a suitable space for a generator is just impossible. The only
current alternative is to increase the UPS battery capacity, but this is
expensive both in terms of maintenance and replacement costs, and they
take up room.
The solution quite simply is Fuel Cells.
Fuel
Cells are quiet, they operate inside the server room, they are fuelled
by either methyl alcohol or hydrogen, and they emit only water vapour
and a small amount of heat. Like generators, they run as long as there
is fuel available. They need minimum maintenance, and will pay for
themselves in just five to six power cuts.
The Technology
Fuel cells convert chemical energy into electrical energy by using spare electrons which are rejected when combining hydrogen with oxygen to create water. These spare electrons are fed into a circuit and create the electrical current.
This done using three plates sandwiched together,
the anode, an electrolyte membrane and the cathode. Hydrogen passes
across the anode plate, which rips off positive and negative ions. At
the same time, air passes across the cathode plate. The hydrogen
positive ions are drawn through the electrolyte membrane, through the
cathode plate, and then combine with the oxygen in the air to create
water. The membrane prevents the negative ions from the hydrogen from
passing through, and these are fed around an external cable to the
cathode, and in doing do, they create the electrical current.
The voltage is very low, so a number of fuel cell plates are sandwiched together to form a stack. These are then electrically connected together to raise the output voltage to a usable level.
Fuel Cells and Power Protection
A Fuel Cell unit is used in combination with a standard UPS. When a power outage occurs, the UPS provides uninterrupted power to the load using its batteries, and ensuring that the servers keep running. At the same time, a start signal is automatically sent to the fuel cell and the gas flow commences. It takes approximately 60 seconds for the fuel cell to be fully operational, and then it supplies DC power into the UPS and takes over from the batteries, again with no interruption in the supply.
Installation
Every installation is different, dependant mainly on the size of the UPS, but typically, a fuel cell will fit into a standard computer rack. The exhaust is moist air, and can create a high humidity in the server room. For this reason, we recommend the fuel cell be positioned near to, or against an outside wall so that this moist air can be ducted to outside. We also fit and extractor fan to help it on its way.
The heat output is low, but it is worth checking that the air conditioning has sufficient capacity to cope.
The hydrogen must be stored outside. It is a flammable gas, but lighter than air. If there is a leakage, it will simply rise up into the atmosphere.
All the gas bottles are connected to a manifold so
that any one can be isolated before swapping out, and a copper or
stainless steel pipe is installed to carry the gas to the Fuel Cell.
Maintenance
The maintenance on fuel cells is minimal. An annual inspection is mostly all that is needed. The air-filter will need to be replaced periodically, and sometimes a worn out fan.
Life Expectancy
A fuel cell will run for approximately 5,000 hours, and for most standby power applications this will give an overall life of between 10 to 20 years.
The Cost
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