Heat Dissipation System

Better heat-dissipating systems were found in the use of narrow bore tubes. The small volume of the tube has a large surface of the internal wall to dissipate the produced heat. The lower the ratio of the volume to surface of a tube (Eq. 17.2), the better the heat dissipation and thus higher the separation efficiency. 

Electrophoresis in narrow bore tubes, as performed by Hjerten in 1967, provides a better heat dissipating system. He described an application using glass tubes with an internal diameter (I.D.) of +3 mm. The small volume of the narrow bore tube improves the dissipation of heat due to a lower ratio of the inner volume to the wall surface of a tube (Equation (1)). The better the heat dissipation the higher will be the separation efficiency ... 

P. Hui and H. S. Tan, Temperature Distributions in a Heat Dissipation System Using a Cylindrical Diamond Heat Spreader on a Copper Sink, J. Appl. Phys. (75/2) 748-757,1994. 

The primary coolant system removes more than 9d per cent of the heat generated in the reactor. This system is divided functionally into two portions a heat removal section in the 105 H Building and a heat dissipation system in the 109 N Building ... 

Instrumentation has been provided to measure and> where necessary to control pertinent variables in the heat removal and heat dissipation systems. The pertinent variables and mode of control are shown In Table 6- k ... 

The 105-N and 109-N Buildings house the reactor, the heat dissipation system, reactor controls and other auxiliary systems and functions. These buildings are divided Into zone which provide for confinement and control of radioactive contamination. 

R. E. Hall, who wrote the section on control of the heat dissipation system In Appendix C, and who also aided In the preparation of other phases of the volume. 

As component and subsystem studies yield additional results studies of the Integrated reactor and heat dissipation system complex wHI be extended and refined, with special emphasis on optimizing oontrol of the heat dissipation system. 

Westinghouse are developing a 36 V electric vehicle lithium-aluminium-iron sulphide battery which has a specific energy of 112 W h/kg on the basis of cell mass and 98 W h/kg on the basis of battery module weight including heat dissipating system. 

Note 2 Since no system can be heal adiabatic in practice there is a ce.rtain amount of heat dissipation from the impregnated windings to the stator core and housing. This heat dissipation is considered as 15% of the total heat generated as in lEC 60079-7. 

With normal interrupting devices the fault current would last for only a few cycles (maximum up to one or three seconds, depending upon the system design). This time is too short to allow heat dissipation from the conductor through radiation or convection. The total heat generated on a fault will thus be absorbed by the conductor itself. 

If the system eannot handle the heat dissipated by this loss at its maximum speeified ambient operating temperature, then another design approaeh should be taken. This loss determines how large a heatsink the linear regulator must have on the pass unit. 

This is usually a closed tank or vessels that hold the volume of fluid required supporting the system. The vessels normally provide several functions in addition to holding fluid reserves. The major functions include filtration of the fluid, heat dissipation, and water separation. 

The overall conceptual layout of the pulsed dye laser LGS system is shown in Fig. 18. A thermally insulated room located on the dome floor houses much of the laser system to minimize vibrations on the telescope and the heat dissipated within the dome. The enclosure houses 6 frequency-doubled Nd YAG pump lasers, the DM0, the associated laser electronics and diagnostics, the... 

Fiber laser guide star systems. It is now widely appreciated that the heat- dissipation characteristics of fibers, coupled with the high efficiencies demonstrated (> 80%) and excellent spatial mode characteristics, make fiber lasers a preferred candidate for many high power applications. Based on these features, fiber laser technologies would provide a compact, efficient, robust, turnkey laser source, ideally suited for LGS applications. 

Adiabatic heat storage or accumulation tests are performed to obtain data on temperature-and pressure-time behaviour of a substance at quasi-adiabatic conditions. Where heat dissipation by evaporation is anticipated, the measurements have to be performed in a closed system. If this is not the case the experiment may be carried out in an open system. 

Performance data Percolation is being measured with a lysimeter connected to flow monitoring systems, soil moisture is being measured with water content reflectometers, and soil matric potential and soil temperature are being monitored with heat dissipation units. From November 1999 to July 2002, the capillary barrier cover system had a cumulative percolation of 0.5 mm. Total precipitation was 837 mm over the 32-month period. Additional field data were collected through 2005. 

Under isobaric conditions, a small amount of energy is consumed or released by expansion or contraction of the system, and AHr is the observed (i.e., net) heat dissipated or absorbed. 

Runaway reactions can be triggered by a number of causes, but, in most cases., their resultant features after initiation are similar [31]. Whenever the heat production rate exceeds the heat removal rate in a reaction system, the temperature begins to rise and can get out of control. The runaway starts slowly but the rate of reaction accelerates, and the rate of heat release is very high at the end. Most runaways occur because of self-heating with the reaction rate (and reaction heat output) increasing exponentially with temperature, while the heat dissipation is increasing only as a linear function of the temperature. 

A typical graph of k as a function of temperature is shown in Figure 3.6. The increasing slope shows the importance of determining a maximum allowable temperature in process equipment so that the heat removal capacity is not exceeded. Under adiabatic conditions, the temperature will reach the calculated maximum only if the reactants are depleted. The actual maximum temperature in a system with some heat dissipation will, of course, be somewhat lower than the calculated value. 

Insulation of the system, resulting in less heat dissipation... 

The thermostatting systems that are applied maximize the Joule heat dissipation through cooling either air (forced air convection or with a Peltier device) or liquid (Peltier device) circulation. In most of the comparisons of temperature control by air and liquid circulation, it was shown that liquid-thermostatting systems perform best [31,77]. 

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