Batteries and Fuels for Powered Equipment

Moving product through a warehouse cannot take place without some form of powered equipment. This chapter will address the various means that provide power for forklifts. There are several specific forms of vehicle power  

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Since these forklifts had previously been powered by heavier batteries, one issue in the modification was weight. The fuel cell power pack itself was relatively easy to integrate into the equipment since it was smaller and lighter than the lead acid battery system. But, since the battery provided part of the counterbalance, additional weight was added to provide enough stability for the forklift. 

Plutonium is the most important transuranium element. Its two isotopes Pu-238 and Pu-239 have the widest applications among all plutonium isotopes. Plutonium-239 is the fuel for nuclear weapons. The detonation power of 1 kg of plutonium-239 is about 20,000 tons of chemical explosive. The critical mass for its fission is only a few pounds for a solid block depending on the shape of the mass and its proximity to neutron absorbing or reflecting substances. This critical mass is much lower for plutonium in aqueous solution. Also, it is used in nuclear power reactors to generate electricity. The energy output of 1 kg of plutonium is about 22 million kilowatt hours. Plutonium-238 has been used to generate power to run seismic and other lunar surface equipment. It also is used in radionuclide batteries for pacemakers and in various thermoelectric devices. 

Italy - the first hydrogen-powered urban fuel cell bus was developed by Iveco/lrisbus for the municipal transport authority of Turin in 2001. The bus, in hybrid configuration, is fuelled with hydrogen (electrolysis) and equipped with a battery system. The fuel cell is supplied by International Fuel Cells and has a power rating of 60 kW. 

A second IEEE report, which does explain its mnemonics, and which competes for mention here, is by Tolbert etal. (2002), which predicts the arrangement of the electrical equipment for heavy hybrid electric vehicles capable of operating in fuel-cell-only mode, engine-only mode and with both power sources. To achieve minimum THD (Total Harmonic Distortion) use is made of cascade multilevel voltage inverters allied to batteries... 

A different approach is to reconsider the airship as a means of air travel. A first approach to this is considering an airship for high-altitude cruising (or as a stratospheric platform) powered by photovoltaic panels and using a reversible fuel cell system to store surplus solar power and use it when the sim is not visible. In this way, carrying possibly heavy batteries may be avoided. The envisaged relative shares of direct use of solar power, of elec-trolyser operation and of fuel cell power production are shown in Fig. 4.12. So far, testing of the equipment sketched in Fig. 4.12 has been performed on a 1-kW scale in the laboratory and in simulated airship conditions. 

For instance, if there are high amp draws from motor start ups, etc., put a supercapacitor in parallel connection with a 12 volt rechargeable battery, and use this to supply those intermittent load needs adequately. To use a rechargeable battery alone, as mentioned, simply connect the output from the fuel cells to the battery and draw power from the battery. To use a supercapacitor and rechargeable battery, connect the battery and supercapacitor in parallel, connect the fuel cell output to these, and draw your power from the supercapacitor and battery connected leads. With these system additions you will need a diode so that reverse flow does not occur to the fuel cell stack, and fuse the circuit on both sides in case of shorts. A switch, either remote or direct, should be used to connect the power supply with any lines or equipment being powered. If you have AC power requirements you will need an inverter to convert DC to AC electricity. 

To adapt a personal mobility scooter to fuel cell-powered operation, it was first necessary to determine peak and average power requirements of a standard battery-equipped scooter. A battery-powered scooter was equipped with current and voltage monitoring circuitry and was driven under common operating conditions. A minimum power output requirement for the fuel cell stack was found. The scooter electrical system and physical... 

A satellite or spacecraft bus is the general model upon which multiple-production satellite spacecrafts are often based. The bus is the spacecraft infrastructure, usually providing locations for the payload (typically space experiments or instruments). The bus is made up mainly of the satellite structure, the electrical power system including the solar panels, the batteries and the power control unit (PCU), the fuel tanks and thrusters. This is often a recurring part reused and adapted from satellite to satellite. The payload includes mission equipment such as antennas, transponders, cameras, telescopes, detectors, instruments for scientific experiments, etc. 

Requirements for the availability of the electrical power sources should be stated for all operational states. These include off-site sources on-site generators (diesels and gas turbines, including associated fuel reserves) batteries and associated control protective, distribution and switching devices. The operability requirements should be such that sufficient power will be available to supply all safety related equipment necessary for safe shutdown of the plant, and for the mitigation and control of accident conditions. The operabihty requirements should determine the necessary power, redundancy of supply lines, maximum permissible time delays and necessary duration of the emergency power supply. Equivalent requirements should be stated for other power sources (for example, the pneumatic power system). Particular care should be taken to ensure that electrical supplies remain adequate in shutdown operations, when many systems and components will be out of service for maintenance. 

Since the power supply for a variety of portable devices is one of the more important future applications of PEMFCs, great efforts are made at present to reduce the dimensions and weight and even to miniaturize both the fuel cell battery and all ancillary equipment needed for a power plant. This aspect is discussed in more detail in Chapter 17. 

The most important performance indicators for power supplies designed for portable equipment are the specific energy per unit mass (weight), Ym (in J/kg) and/or per unit volume, Yi> (in J/L). Often, miniplants with fuel cells are used in portable equipment as a replacement for lithium-ion batteries, which have specific performance indicators of 150 Wh/kg and 350 Wh/L. 

It is quite clear that we do not expect complete substitution of ordinary batteries by fuel cells in the portable field. Ordinary batteries will continue to maintain their leading market position as power sources for a large number of devices. Thus, disposable batteries are expected to maintain their importance for pocket flashlights and various medical devices, for example. Simple electronic devices such as portable radios, audio players, digital cameras, and so on, will continue to be powered by rechargeable nickel-cadmium and nickel-hydride batteries. Lithium-ion rechargeables are likely to continue in simpler mobile phones. Fuel cells will be attractive for more complex equipment, such as notebooks used for more than 2 hours at a time, for instance, where even lithium-ion batteries have insufficient energy density. 

In some cases the models for designing such hybrid systems are quite well developed, because they have already been used for solar panel-battery hybrid systems. These are very widely used in telecommunications and navigation equipment. In comparison, the model needed for a fuel cell-based system is much simpler, since with the solar panel both the consumption and generation of power vary in a mixture of random and predictable ways. With fuel cell-based hybrid systems, the primary generation of electrical power can at least be leUed upon and accurately modelled. 

The development of fuel cells that may be competitive with batteries in the low power range for use in cellular phones, laptop computers and other similar equipments will require innovative designs incorporating thinner components and smaller light-weight auxiliaries. Scale-down of current fuel cell technology will not be adequate to meet the size and weight... 

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