Coolers electric heater controls

Armed with the thermodynamic fundamentals of heat management, we now take a closer look at the unit operation control loops for heat exchangers. We start with utility exchangers. These are used when heat is supplied to, or removed from, the process. Examples are steam-heated reboilers, electric heaters, fuel-fired furnaces, water-cooled condensers, and refrigerated coolers. 

The G.P. chamber is equipped with an air cooler of about 5500 BTU size (Item 3) is located about 1.8 meters off the floor. An evaporator control valve (Item 2) on the refrigerate line allows temperature control of the air cooler condenser coils. Temperature of the coils is maintained just above the dew point for 50% relative humidity. An electric baseboard heater (Item 6) is equipped with a hydrastatic thermostat control (Item 11). The base board heater is placed near the floor and opposite of the chamber door. A humidifier (Item 4) is located approximately 1.8 meters above the floor and just to the right of the air cooler. The nozzle of the humidifier is pointed slightly toward the back of the chamber. A humidistat (Item 10) is centered between the floor and end walls on the same side as the humidifier. A strategically located recording hygrothermograph is used to monitor both temperature and humidity. 

The ASTM- (or DIN-) standard method for low conducting solid material (X" ) is the two plate method with an electrical main heater between two cylindrical sample plates having a small length to diameter ratio and two heat sinks as well as a cylindrical guard heater (Figure 2). For better temperature control each heat sink consists of an electrical driven auxiliary heater and a water cooler. In this case the heat flow rate to each of the two samples is given by... 

Fig. 14.4 Schematic representation of a reaction vessel [72] of isothermal compensation flow calorimeter, a inlets b outlet c electrical leads d Peltier cooler e controlled heater / isothermal cylinder g calibration heater h inside tube...

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