A house is heated in winter by a biogas boiler. The boiler is rated at 70,000 Btu/h. The heating value of biogas is 13,000 Btu/h and the average boiler efficiency is 87 percent. Taking the total win- ter period to be 3000 hours and assuming that the boiler operates at an average load of 75 percent, determine the amount of biogas consumed in therm (1 therm = 100,000 Btu) in the winter season. If the biogas is sold at a unit price of $1.20/therm, determine the cost of this biogas to the homeowner.

Apump is used to circulate hot water in a home heating system. water enters the well-insulated pump operating at steady state at a rate of 0.42 gal/min. the inlet pressure and temperature are 14.7 lbf/in.2, and 180°f, respectively; at the exit the pressure is 60 lbf/in.2 the pump requires 1/15 hp of power input. water can be modeled as an incompressible substance with constant density of 60.58 lb/ft3 and constant specific heat of 1 btu/lb or. neglecting kinetic and potential energy effects, determine the temperature change, in °r, as the water flows through the pump.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false

Most leaks in reciprocating air compressors can be detected and minimized by: (clo4) a)-detecting leakage areas using ultrasonic acoustic detector. b)-tightening joints and connections c)-replacing faulty equipment d)-all of the given options