Attic space

I40C Consider a house whose attic space is ventilated effectively so that the air temperature in the attic is the same as Ihe ambient air lempeiaiure at all times. Will the roof still have any effect on heat transfer through the ceiling Explain. 

Hot air at atmospheric pressure and SOX enters an 8-m-long uninsulated square duct of cross section 0.2 m x 0.2 m that passes through the attic of a house at a rate of 0.15 m /s (Fig. 8-31). The duct is observed to be nearly Isolhermal at 60°C. Determine the exit temperature of the air and the rale of heat loss from the duct to the attic space. 

An 8-m long, uninsulated square duel of cross section 0.2 m X 0.2 m and relative roughness 10 passes through the attic space of a house. Hot air emers the duct at 1 atm and 80°C at a volume flow rale of 0.15 mVs. The duct surface is nearly isothermal at 60°C. Determine the rate of heat loss from the duct to the attic space and the pressure difference between the inlet and outlet sections of the duct. 

Attic Ventilators- In houses, screened openings provided to ventilate an attic space. 

Kneewall - A wall usually about 3 to 4 feet high located that is placed in the attic of a home, anchored with plates between the attic floor joists and the roof joist. Sheathing can be attached to these walls to enclose an attic space. 

Thermal Envelope Houses - An architectural design (also known as the double envelope house), sometimes called a "house-within-a-house," that employs a double envelope with a continuous airspace of at least 6 to 12 inches on the north wall, south wall, roof, and floor, achieved by building inner and outer walls, a crawl space or subbasement below the floor, and a shallow attic space below the weather roof. The east and west walls are single, conventional walls. A buffer zone of solar-heated, circulating air warms the inner envelope of the house. The south-facing airspace may double as a sunspace or greenhouse. 

Piles of rubbish and debris in the workplace are one of the most common causes of fires and high standards of housekeeping are an important feature of fire prevenhon. Horizontal surfaces in overhead areas, such as structural beams and trusses and attic spaces, allow large amoxmts of dust to collect. Dust shaken down from roof trusses is a major factor in the severity of dust explosions in factories, while flames running across the surface of dust can result in a very rapid spread of fire to xmexpected areas. This latter feature was one of the causes of the spread of fire in St George s Chapel at Windsor Castle in 1992. 

As suggested by Heumann, and on basis the writers own observations, any void or attic space above the inlet plane tends to cause incoming solids to... 

It is not uncommon for a pair of pliers to climb all the way from the cellar to the attic in its single-minded determination to raise its owner s blood pressure. Keys have been known to burrow three feet under mattresses. Women s purses, despite their great weight, frequently travel through six or seven rooms to find hiding space under a couch. 

Keyless- A plastic or porcelain light fixture that operates by a pull string. Generally found in the basement, crawl space, and attic areas. 

Attic - The usually unfinished space above a ceiling and below a roof. 

Radiant Barrier - A thin, reflective foil sheet that exhibits low radiant energy transmission and under certain conditions can block radiant heat transfer installed in attics to reduce heat flow through a roof assembly into the living space. 

Whole House Fan - A mechanical/electrical device used to pull air out of an interior space usually located in the highest location of a building, in the ceiling, and venting to the attic or directly to the outside. 

The concept on which the Attic method is based is that any feasible point (vertex or nonvertex) sees the solution (it can be joined to the solution by a line) as the space is convex for all the linear programming problems (Buzzi-Ferraris, 2011b). 

In a convex space, every vertex or feasible point can be joined by a straight line to the solution. Often, such a line must leave one or more constraints that the working point is lying on and pass through the attic to achieve the solution the Attic method leaves one or more constraints when it is advantageous, while the Simplex method cannot. 

The simplest example of Attic in a three-dimensional space consists of an ordinary room with a parallel floor and roof as well as parallel pairs of side lateral walls. Within this simple Attic there are three (like the space dimensions) couples of mutually incompatible constraints. It is easy to generalize this problem the ny dimensions can be larger than 3 complementary constraints can be nonparallel on condition that they do not meet each other within the feasible region distances between opposite vertices in the complementary constraints can be different, but not zero. 

Conventionally heat insulation is applied (a) on the walls, (b) in the basement (under floors above unheated spaces, around walls in a heated basement or unventilated crawl spaces, as well as on the edges of slabs-on-grade) and, (c) in the attic (including the attic door or hatch cover). These are the main locations of heat loss in houses. It is estimated that, only air infiltration through openings in the house envelope can account for the 30-40% of heat loss in a typical home. 

Crawl Space n A shallow, unfinished space beneath the first floor of a house which has no basement, used for visual inspection and access to pipes and ducts. Also, a shallow space in the attic, innnediately under the roof... 

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