Thermodynamics

750 | ThermodynamicsDesign and Essay Problems14–153 The condensation and even freezing of moisture inbuilding walls without effective vapor retarders are of realconcern in cold climates as they undermine the effectivenessof the insulation. Investigate how the builders in your area arecoping with this problem, whether they are using vaporretarders or vapor barriers in the walls, and where they arelocated in the walls. Prepare a report on your findings, andexplain the reasoning for the current practice.14–154 The air-conditioning needs of a large building canbe met by a single central system or by several individualwindow units. Considering that both approaches are commonlyused in practice, the right choice depends on the situationon hand. Identify the important factors that need to beconsidered in decision making, and discuss the conditionsunder which an air-conditioning system that consists of severalwindow units is preferable over a large single centralsystem, and vice versa.14–155 Identify the major sources of heat gain in yourhouse in summer, and propose ways of minimizing them andthus reducing the cooling load.14–156 Write an essay on different humidity measurementdevices, including electronic ones, and discuss the advantagesand disadvantages of each device.14–157 Design an inexpensive evaporative cooling systemsuitable for use in your house. Show how you would obtain awater spray, how you would provide airflow, and how youwould prevent water droplets from drifting into the livingspace.