Design and Essay Problems
14–153 The condensation and even freezing of moisture in
building walls without effective vapor retarders are of real
concern in cold climates as they undermine the effectiveness
of the insulation. Investigate how the builders in your area are
coping with this problem, whether they are using vapor
retarders or vapor barriers in the walls, and where they are
located in the walls. Prepare a report on your findings, and
explain the reasoning for the current practice.
14–154 The air-conditioning needs of a large building can
be met by a single central system or by several individual
window units. Considering that both approaches are com-
monly used in practice, the right choice depends on the situa-
tion on hand. Identify the important factors that need to be
considered in decision making, and discuss the conditions
750 | Thermodynamics
under which an air-conditioning system that consists of sev-
eral window units is preferable over a large single central
system, and vice versa.
14–155 Identify the major sources of heat gain in your
house in summer, and propose ways of minimizing them and
thus reducing the cooling load.14–156 Write an essay on different humidity measurement
devices, including electronic ones, and discuss the advantages
and disadvantages of each device.
14–157 Design an inexpensive evaporative cooling system
suitable for use in your house. Show how you would obtain a
water spray, how you would provide airflow, and how you
would prevent water droplets from drifting into the living
space.