Internal liquid cooling

In internal liquid coohng system, a liquid circulates through critical components to remove heat in the case of fire. This normally requires tubular or cellular sections of the protected components. Such systems have been implemented in car engines and rocket nozzles for decades. 

Buildings with incorporated internal hquid coohng systems into structural steel skeletons have already been built [15]. In such buildings, the members are normally 

Chapters 6 and 7 demonstrated a successful implementation of an active water cooling system in FRP cellular sections for beam (or slab) and column (or wall) apphcations in building structures. Key results are summarized in Section 9.5, with a further extension of such an active fire protection system to heating and cooling usages. 

Passive Fire Protection Appiications with FRP Components 

The experiment was stopped because of the structural collapse of the specimen at 65 min after fire exposure started. The failure occurred due to the distortion and wrinkling of the web at the loading point and the CS board was also broken as a result of the failure of the GFRP profile. In comparison to the same GFRP profile without any fire protections, the fire resistance time improved by 71% (from 38 to 65 min). 

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An internal liquid cooling system as an active fire protection was implemented in full-scale GFRP panels for beam and column applications, the resulting thermal responses have been introduced and modeled in Chapter 6 and the mechanical responses in Chapter 7. The fire endurance time of each scenario is summarized in Table 9.1 and more details can be found in the previous chapters. It can be concluded that combined mechanical loading and fire experiments on full-scale water-cooled cellular slabs and columns proved the feasibility of an effective fire protection. Fire endurance durations of up to 2 h could be reached at slow water... 

Table 9.1 Fire endurance time of full-scale GFRP beams and columns subjected to ISO 834 fire curve with active fire protection (Internal liquid cooling).

Fig. 20.10 Basic HT-PEMFC stack concepts with internal air cooling (left) and internal liquid cooling (right) [19]...

For steam jacketed, agitated closed reactor ketdes, the overall U usually will range from 40-60 Btu/hr (ft ) ( F). Of course, the significant variables are the degree or type of internal wall turbulence and the viscosity and thermal characteristics of the internal fluid. For water or other liquid cooling in the reactor jacket, the U value usually ranges from 20-30. 

Internal liquid injection into the diffuser passage is used in a few applications for direct contact cooling. The quantity and quality of the liquid must be carefully controlled. 

The values for polytropic conditions represent an uncooled compressor, that is, no internal diaphragm cooling, no liquid injection, and no external coolers for the pressure range being considered. 

Liquid cooled internal combustion engines require a circulating coolant to remove excess heat. While water is an effective heat transfer fluid, it has serious shortcomings as an engine... 

A possibility is to saturate at different temperatures the reactants before they enter into the stack [33]. This approach can be accomplished by several procedures based on external dewpoint, external evaporation, steam injection with downstream condensers, or flash evaporation. High temperature values allow to absorb significant water amount in gas streams and then transport it inside the stack compensating the water losses due to internal fast evaporation. However, the main problem with external humidification is that the gas cools after the humidifier device, the excess of water could condense and enter the fuel cell in droplet form, which floods the electrodes near the inlet, thereby preventing the flow of reactants. On the other hand, internal liquid injection method appears preferable for example with respect to the steam injection approach because of the need of large energy requirement to generate the steam. 

Product Heat Management Process Gas + Liquid Coohng Mediiun Process Gas + Electrolyte Circulation Process Gas + Liquid cooling mediiun or steam generation Internal Reforming + Process Gas Internal Reforming + Proeess Gas... 

Besides active cooling with air or with liquids like oil, stacks can also be cooled with water. The effects of water cooling are estimated by the authors only theoretically. The reason is the pressurization of the water cooling circuit, which is necessary not only for the conventional water cooling but also for the phase change concept. At ambient pressure of 1 bar the internal water cooling would cause a stack temperature of round about 100 °C due to the evaporation at... 

Heat removal at intermediate points on the tower can be attained by withdrawing an internal liquid stream from the tower, cooling it and returning it to the column. The cooling medium is usually the crude oil charge which is being preheated before entering the furnace. Thus, a dual benefit is reaUzed. This can be done in one of two ways. 

Figure 22-8 shows the features of a horizontal center-fed column [Brodie, Au.st. Mech. Chem. Eng. Tran.s., 37 (May 1979)] which has been commercialized for continuous purification of naphthalene and p-dichlorobenzene. Liquid feed enters the column between the hot purifying section and the cold freezing or recovery zone. Ciystals are formed internally by indirect cooling of the melt through the walls of the refining and recovery zones. Residue liquid that has been depleted or product exits from the coldest section of the column. A spiral conveyor controls the transport of solids through the unit. 

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