Comparison of Fuel Cell Types - Report Example

Similar to a dry cell, a fuel cell produces electricity from the reaction of electrochemical. Similar to batteries, electrical energy is transformed from chemical energy, and consequently, heat is generated as a by-product of the system. Moreover, it employs an external dispense of chemical energy and thus can operate continuously, provided that the cell is provided with a source of oxygen generally from the air and hydrogen, despite the absence of combustion. Models of fuel cells are diverse with a various output of energy such as electricity that ranges from minor watts to substantial megawatts. Furthermore, an attribute of fuel cells is in accordance to the composition of the electrolyte applied as well as the fact that each model necessitates fuels and resources, which render it appropriate for large implementations (FuelCellToday, 2012). Therefore, this concept of fuel cells forms the basis of my essay that aims to compare various forms of fuel cells and the benefits associated to them, disadvantages, and perspectives of applications.

The Polymer Electrolyte Membrane (PEM) Fuel Cell

One of the several models of contemporary fuel cells is the polymer electrolyte membrane fuel cell (PEMFC), which also recognized as proton exchange membrane fuel cell as shown in Figure 1. This model adopts its name from the version of electrolyte, which is a polymer diaphragm with an elevated conductivity of proton usually when the membrane is appropriately hydrated (Tang et al., 2007). Well, an example of the most common polymer employed in PEM cell models is the Nafion which is constructed with a perflourosulfonic acid polymer that is chemically stabilized (Feroldi & Basualdo, 2012).

Therefore, in PEM fuel cells mobility of protons is experienced via the fluid suspension to the cathode where there is mixing of electrons and oxygen, generating heat and water. In essence, the polymeric diaphragm is used with platinum electrodes (Tang et al., 2007).

Figure 1: Shows the structure of PEM fuel cell

Solid Oxide Fuel Cells (SOFC)

Solid oxide fuel cells (SOFC) is an energy transformation system that generates electrical energy with permanently reduced adverse effect on the environment. The cells utilize solid concrete, ceramic electrolytes such as zirconium oxide that is stabilized with yttrium oxide as opposed to a liquid and function in temperatures of about 800 to 1000 degree Celsius. Also, this model encompasses an anode and a cathode rods that serve as electrodes together with the electrolyte media. Typically, the permeability of the electrodes enables the discharge and conduction of electrons and possibly while functioning at that temperature SOFC could initiate an ionic conductivity (Taroco et al., 2011). For instance, the movement of negative ions to the positive electrode is via the electrolytic conductor where they amalgamate with hydrogen to produce electrons and water. Indeed, the electrolyte must be concentrated with the suitable ion-conducting attributes.

Fig. 2: Shows the structure of the SOFC fuel cell

Ceramic Fuel Cells

They are connected to SOFC fuel cells whose fabrication could be designed by depositions suspension that are comprised of ceramic powders, solutions, binders, plasticizers, and dispersants. These suspensions are usually employed to create surface charges of SOFC fuel cells. Besides, the materials require optimization of every single element and suitable measures to stabilize the suspension. Consequently, the functionality of the ceramic material cells at minimum temperatures is associated with a significant reduction in SOFC cell productivity. Considerably, the solution to ameliorate the performance of the battery involves the application of alternative constituent materials with increased production of the SOFC fuel cells (Taroco et al., 2011).

Biofuel Cells

These are apparatus that employ biocatalysts to transform chemical energy to electrical power. Normally, this advancement aims to produce energy from a complete cell organism or rather microbial associated biofuel cells, whereby there is a chain movement of electrons between the fuel sediments and the surface of the electrode. However, researchers consider this mechanism as yet to fully become operational whereby it can be implemented outside the laboratory and venture into mainstream trade (Heydorn & Gee, 2003).

Comparing the Fuel Cell Types

Benefits

Accordingly, the fuel cells are considered as the proposed energy mechanisms with an increased potential for environmentally safe transformation of energy. It is apparent that there are several benefits associated with the fuel cells. In essence, the quantity of energy supplied by a fuel cell is subject to various aspects that include: the fuel cell prototype as well as its dimensions. Also, the estimated temperature that the cell uses to function, and the magnitude of compression of the gases connected to the battery (FuelCellToday, 2012). Therefore, given PEMFCs, SOFC and biofuel cells, their interests can be correlated as follows:

First and foremost, PEM fuel cells, their functionality is dependent on proportionately minimum temperatures and thus, rendered most efficient candidates or vehicles, buildings as well as minor implementations. Similarly, SOFC systems are mainly known for their increased efficiencies due to low pollution effect and also established for production at a range of high temperatures about 900 to 1000 degrees Celsius that yields elevated standard exhaust heat for cogeneration. Moreover, the high temperatures ensure that when the heat is pressurized, it can be combined with a gas turbine to progressively multiply the total efficiency of the power structure (Singhal, 2007). Biofuels are relatively cheap and do not demand the use of precious-metal catalysts as well as employ an appropriate pattern of cathode and anode divided by a polymeric ceramic diaphragm (Heydorn & Gee, 2004).

Besides, the PEM fuel cells are beneficial in its capacity to supply increased power density and provide the rewards of minimal weight and function in contrast to other fuel cell models. However, SOFCs generate power at high productivity, solely because their efficiencies are not restricted by the Carnot pattern of a heat engine. Thus, the fuel cells contribute to several benefits over customary systems of energy transformations that comprises of reliability, high efficiency, fuel adaptability, reduced emission levels of nitrous and sulfur oxides (Taroco et al., 2011). Similarly, biofuels are believed to meet the demand of lightweight source of energy and supply even in remote regions through small instruments (Heydorn & Gee, 2004).

Furthermore, FEM fuel cells only use hydrogen, oxygen, and water to function, and thus does not need acidic fluids like conventional fuel cells. Similarly, since the SOFC uses a solid electrolyte, the cells barely need to be assembled in the plate-like arrangement common in other fuel cells. Besides, due to the use of high temperatures, there is no requirement for catalysts of precious-metal thus minimizing operational costs. Besides, SOFCs operate quietly, and vibration free that ensures the prevention of noise related to traditional systems of power generations. On a similar note, PEM fuel cells utilize low temperature that enables the system to commence rapidly and hence, prevents wearing of the system elements as an outcome and thus, improves durability (Singhal, 2007).

Limitations

On the other hand, the fuel cells are associated with various distinct boundaries. For instance, a significant restriction of fuel cells is the increased charges of operation and specifically, heightened costs of hydrogen production. Therefore, more limitations can be discussed through a comparison between the PEMFC, SOFC and biofuel cells such as:

The PEM fuel cell necessitates a precious metal catalyst (essentially platinum) that would be implemented to differentiate the electrons from the hydrogen and protons, and consequently, multiplying the cost of the operation. Likewise, the SOFCs experience difficulty of combining materials such as ceria or strontium titanate and ceria mixtures for anode designs with available cell and stack construction operations and resources (Singhal, 2007). Similarly, scientists have expressed that the most massive challenge in development of biofuel cells is the lack of funds that would enable to use better technological equipment.

Besides, PEM fuel cells are constrained by the phenomenon of the platinum catalyst that is intensely vulnerable to carbon monoxide (CO) poisoning and hence renders it in need to apply a supplementary responsive element to avert CO collected as a result of the reaction of fuel, in the event that hydrogen is obtained from a hydrocarbon or a compound of ethanol. Ultimately, it results in increased costs. Moreover, for the SOFC fuel cells, the issue of usage of high temperatures has also been a limitation leading to the reduced durability of materials and high costs. Therefore, researchers have investigated the possibility to implement the operation with temperatures of about 800 degrees Celsius and below (Taroco et al., 2011).

Furthermore, researchers argue that the use of hydrogen by both fuel cells could be explicitly overestimated because hydrogen does not form the primary source of fuel. In essence, hydrogen is generated from hydrocarbons restructuring or water electrolysis (Feroldi & Basualdo, 2012).

The fact that PEM fuel cells demand pure hydrogen with zero CO to efficiently operate, there is a lack of hydrogen infrastructures as well as on-board improvement apparatus to generate hydrogen from obtainable fuel reservoirs such as gasoline or diesel, which are technically complicated, challenging and costly. Moreover, it is strenuous to eradicate the CO entirely from the enhanced stream (Singhal, 2007). Likewise, the application of biofuels is near to impossible due to the lack of novel implementations in contemporary society (Heydorn & Gee, 2004).

Applications

Considerably, fuel cells can employ as portable and stationary use. Given the fuel cell models, stable implementations would encompass minor households, cogeneration of average size or massive manufacturing plants. For instance, in the free sections, fuel cells such as the PEMFCs that are characterized with reduced temperatures are implemented for passenger vehicles and wide-load trucks, trains, additional power models for airplanes as well as boats. Besides, usage of mobile fuel cells comprises of portable, minimal power mechanisms for different applications (Schoots et al., 2010).

On the other hand, SOFC fuel cells are employed in planar stationary power production processes that range between 1kW to 25 kW capacity and have been constructed and evaluated by various institutions. This application is valid when employed in tubular SOFCs, Westinghouse or Siemens development of 100kW power generation of the atmospheric system. Another application concept of SOFCs is in a locomotive category, whereby despite the widespread application of PEM fuel cells in mobile sections, the limitation concerning pure hydrogen and complete elimination of CO causes SOFCs to excel in the transportation sector. Frequently, the SOFCs can utilize CO alongside hydrogen fuel, and thus operates at usual measurements of water and temperature on the anode side that ensures enhancement of in-stock and on-cell of hydrocarbon fuels achievable. Therefore, its application in locomotives can be on-board additional power sections (APUs), whereby regardless of the demand of the increasing electrical energy, SOFCs would provide luxury locomotives, heavy-load trucks and recreational automobiles (Singhal, 2007).

In the account of the high efficiency associated with fuel cells, the different...