The maintenance manager of your facility has asked you to evaluate a particular welding booth that utilizes a local exhaust ventilation (lev) system to remove the contaminant at the source. the exhaust system does not appear to be drawing enough of the welding fumes away from the employees to reduce the iron oxide below the permissible exposure limit (pel) of 10 mg/m3. during your investigation, you determine that the diameter of the duct system is 8 inches and has an air velocity of 350 fpm (feet per minute). the welding operation is performed at a distance of 1.5 feet from the exhaust opening. determine the flow rate, and provide your recommendations on the control measures that could improve the capture of the iron oxide contaminant.

Aheat pump with refrigerant-134a as the working fluid is used to keep a space at 25°c by absorbing heat from geothermal water that enters the evaporator at 500c at a rate of 0.065 kg/s and leaves at 40°c. the refrigerant enters the evaporator at 20°c with a quality of 23 percent and leaves at the inlet pressure as saturated vapor. the refrigerant loses 300 w of heat to the surroundings as it flows through the compressor and the refrigerant leaves the compressor at 1.4 mpa at the same entropy as the inlet. determine: (a) the degrees of subcooling of the refrigerant in the condenser, b)-the mass flow rate of the refrigerant . (c) the heating load and the cop of the pump, and d)-the theoretical minimum power input to the compressor for the same heating load.