Heat dissipation cooling system design

As discussed later, the enclosure of an IPB may carry induced currents up to 95% of the current through the main conductors. Accordingly, the enclosure is designed to carry longitudinal parasitic currents up to 90-95% of the rated current of the main busbars. The cross-sectional area of the enclosure is therefore maintained almost equal to and even more than the main conductors to account for the dissipation of heat of the main conductors through the enclosure only, unless an additional forced cooling system is also adopted. The outdoors part of the enclosure exposed to atmospheric conditions is also subjected to solar radiation. Provision must be made to dissipate this additional heat, from the enclosure. 

This simple criterion based on the least irreversibility is technically interesting for choosing the most adequate fluid in the optimal design of a certain spray-cooling application. It should be stressed that the optimal wall temperature corresponds to the working temperature of the heat-dissipating surface, which the spray-cooling system is required to maintain at a constant value. 

By far the most (about 96 per cent) of the heat generated In the reactor is removed ffom the reactor by the primary coolant system, transferred to the boiling water secondary system and dissipated to the Columbia River via condenser cooling water streams, failure of the primary coolant system to remove heat from the reactorat design power level will result In certain fuel melting unless the last-ditch backup cooling system functions. 

The fuel eell reaction is exothermal therefore it generates heat as a by-product. To maintain the desired temperature, heat must be removed from the system. Some heat dissipates from the outer surface of the fuel cell and the rest must be taken away with a eooling system. The cooling medium may be air, water, or a special coolant. The inner design of the fuel cell must allow the coolant to pass through, for example, a coolant plate or coolant chaimel on the back of the anode or cathode plate. Small fuel cells need a heater to reach the operating temperature because so much heat is being taken away from the outer surface [1]. The heat balance within a fuel cell can be written as... 

Table 1.6 Heat dissipation by various mechanisms. Especially the figures for forced flow depend on a large number of parameters, e.g. design of the cooling system, flow rate, etc., and the listed values can only be considered as a rough comparison gained by a particular experiment. 

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