Heating Ventilating and Air Conditioning: Analysis and Design
6th Edition
ISBN: 9780471470151
Author: Faye C. McQuiston, Jeffrey D. Spitler, Jerald D. Parker
Publisher: Wiley, John & Sons, Incorporated
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Chapter 5, Problem 5.32P
A small office building is constructed with a concrete slab floor. Estimate the heat loss per unit length of perimeter. Assume (a) R-5 (R-0.88) vertical edge insulation 2 ft (60 cm) wide; (b) edge insulation at slab edge only. Assume an outdoor design temperature of 5 F (—15 C) and indoor temperature of 70 F (21 C).
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An electric wire having a diameter of 1.5 mm and covered with a plastic insulation (thickness = 2.5 mm) is exposed to air at 300 K and ho=20 W/m2.K. The insulation has a thermal conductivity (k) of 0.4 W/m.K.
Assuming the wire surface temperature is constant at 400 K and is not affected by the covering
a)Calculate the value of the critical radius.
b)Calculate the heat loss per meter of wire length with no insulation.
c)Calculate the heat loss per meter of wire length with insulation.
An electric wire having a diameter of 1.5 mm and covered with a plastic insulation (thickness = 2.5 mm) is exposed to air at 300 K and ho = 20 W/m2.K. The insulation has a thermal conductivity (k) of 0.4 W/m.K.Assuming the wire surface temperature is constant at 400 K and is not affected by the coveringa) Calculate the value of the critical radius.b) Calculate the heat loss per meter of wire length with no insulation.c) Calculate the heat loss per meter of wire length with insulation.
p.s Could you write the solution clearly? It is hard to understand when written in text. A paper photo with solution would be better. Thanks in advance
A-For a general office room, the exposed wall (with a window, outside winter type)
construction is 19 mm plaster outside (cement and sand) and 20 cm brick (building). The
area of the window is 50% of the exposed wall. Calculate the heating load required for the
office caused by the wall and window. Take Tout-5 °C and Tin-25 °C, exposed wall
height=3 m and width=5 m, Inside and outside still air thermal resistance fi= 9.37 W/m²°C
and fo= 34.1 W/m2 °C respectively.
(6 marks)
Chapter 5 Solutions
Heating Ventilating and Air Conditioning: Analysis and Design
Ch. 5 - Determine the thermal conductivity of 4 in. (100...Ch. 5 - Compute the unit conductance C for 512 in. (140...Ch. 5 - Compute the unit thermal resistance and the...Ch. 5 - What is the unit thermal resistance for an inside...Ch. 5 - Compute the thermal resistance per unit length for...Ch. 5 - Assuming that the blocks are not filled, compute...Ch. 5 - The partition of Problem 5-4 has still air on one...Ch. 5 - The pipe of Problem has water flowing inside with...Ch. 5 - Compute the overall thermal resistance of a wall...Ch. 5 - Compute the overall heat-transfer coefficient for...
Ch. 5 - Estimate what fraction of the heat transfer for a...Ch. 5 - Make a table similar to Table 5-4a showing...Ch. 5 - Estimate the unit thermal resistance for a...Ch. 5 - Refer to Problem 5-13, and estimate the unit...Ch. 5 - A ceiling space is formed by a large flat roof and...Ch. 5 - A wall is 20 ft (6.1 m) wide and 8 ft (2.4 m) high...Ch. 5 - Estimate the heat-transfer rate per square foot...Ch. 5 - A wall exactly like the one described in Table...Ch. 5 - Prob. 5.19PCh. 5 - Compute the overall heat-transfer coefficient for...Ch. 5 - Compute the overall heat transfer for a single...Ch. 5 - Determine the overall heattransfer coefficient for...Ch. 5 - A basement is 2020ft(66m) and 7 ft (2.13 m) below...Ch. 5 - Estimate the overall heat-transfer coefficient for...Ch. 5 - Rework Problem 5-23 assuming that the walls are...Ch. 5 - A heated building is built on a concrete slab with...Ch. 5 - A basement wall extends 6 ft (1.8 m) below grade...Ch. 5 - A 2440ft(7.312.2m) building has a full basement...Ch. 5 - The floor of the basement described in Problem...Ch. 5 - Assume that the ground temperature tg is 40 F (10...Ch. 5 - Use the temperatures given in Problem 5-30 and...Ch. 5 - A small office building is constructed with a...Ch. 5 - A 100 ft length of buried, uninsulated steel pipe...Ch. 5 - Estimate the heat loss from 100 m of buried...Ch. 5 - A large beverage cooler resembles a small building...Ch. 5 - Consider the wall section shown in Fig. 5-10. (a)...Ch. 5 - A building has floor plan dimensions of 3060ft....Ch. 5 - Compute the temperature of the metal roof deck of...Ch. 5 - Consider the wall section shown in Fig. -4a,...Ch. 5 - Consider the knee space shown in Fig. 5-11. The...Ch. 5 - Estimate the temperature in an unheated basement...
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