HVAC108. Last 50

Typical values of air change rates range from;

0.5 for new construction to 1.0 air changes per hour for leaky, older buildings.

What is the total area of net ceiling for the provided drawing?

1,824 ft²

Calculate BTU loss for windows on the south side based on solar and transmission with a HTM of 52.

3,120 BTU

Using a blueprint with a scale of 1/4 inch = 1 foot and you measure 8 ¾ inches for an exterior wall with a ruler. What is the actual length of the wall?

35 ft

What is the total area of exterior doors, used for calculating heat gain and/or loss for the provided drawing?

38 Sq. ft.

Calculate the total BTU loss for all ceilings from the provided drawing constructed with the following specifications. Total R value =19 Outdoor winter design temperature 18 degrees F. Indoor winter design Temperature 68 degrees F.

4,834 BTU

Calculate the total BTU loss for all exterior walls constructed using the following specifications and the dimensions from the provided drawing. Walls (Insulation R-11, 1/2 inch poly board R-2.5, 2 x 4 wood frame, with Brick exterior finish) Total R value equal 15.5 Winter outdoor design temperature = 18 degrees F. Winter indoor designtemperature = 68 degrees F.

4391 BTU

Find the heat gain for the exposed wall and knee-wall. The building is 20 ft. wide with an exterior wall height of 8 ft. The roof has a 6 on 12 pitch. Insulation R-11 Outdoor Summer design temperature 95 degree F. Indoor design Temperature 70 degree F. Attic temperature 145 degree F.

705 BTUh

Calculate the total BTU heat gain for the ceiling of room 4 using the following construction specifications and the dimensions from the provided drawing. Vented Attic Dark Roof Outdoor Summer design temperature 95 degrees F. Indoor winter design Temperature 72 degrees F. HTM = 2.60

915 BTU

The construction features needed to calculate basement heat loss are;

Above-grade wall, below-grade wall, and basement floor.

The purpose of a home air conditioner is to move heat from inside the home to the outside by;

Absorbing the heat from the inside air into the evaporator.

Reflective foil insulation will conduct to the next solid layer and have an equivalent R-value of zero unless there;

Air gaps between the foil layers.

The term Building Assembly is;

Any part of the building enclosure that has thermal boundary conditions at the interior and exterior of the building.

To control comfort level, and efficiency it is necessary to control the rate of ventilation air;

Based on the number of occupants, size of the building and infiltration rate.

Outer elements of a building, such as walls, windows, doors, roofs, and floors, including those having contact with earth is the ASHRAE definition of what?

Building Envelope.

Heat gain from the sun and internal sources within the building are;

Calculated into the total energy available for heating purposes.

When sizing an air conditioner, what critical information must be known?

Calculated sensible and latent loads.

Windows featuring a hinged sash that uses a crank to swing out left or right are called;

Casement

The ability of a window to absorb certain types of energy and radiate that energy through itself and out of a room is called;

Emissivity

Temperature difference between the inside and outside of a structure and "R" value are;

Factors effecting heat loss and gain calculations.

What are three types of batt insulation?

Fiberglass, cotton and rock wool.

Convection heat transfer occurs when;

Fluids at different temperatures flow within a given space.

When calculating thermal loss or gain;

Fractional measurements are usually rounded to the next or nearest whole number

Low Emittance (E) Glass is;

Glass which has low emissivity due to a film or metallic coating on the glass.

Transmission heat loss is;

Heat transferred through confining walls, glass, ceilings, floors or other surfaces.

When calculating the heating load for a zone, which of the following should be used?

Identify the exposed surfaces by directions, type, and net area of each surface.

Hot and cold spots are caused by;

Inconsistencies in construction, materials, thermal bridges and breaks, settling of sealed materials, and quality of workmanship.

Gross area of the floor for the provided drawing;

Is usually the same as the ceiling. (1824 sq ft)

One nondestructive way to find out if a wall is insulated is to;

Look around the sides and/or behind an electrical outlet on an exterior wall.

Glass with a textured surface which provides low visibility and allows in natural light is called;

Obscure glass.

Spray Foam insulation can be effectively used for sealing;

Open cavities around ducts, pipes, and electrical wiring that pass through the building envelope.

Which of the following is considered an Infiltration load?

Outdoor air leaking in.

Ventilation air should be;

Provided to conditioned rooms through mechanical and/or natural air distribution.

Estimating the rate of infiltration air is difficult, because it depends on the;

Quality of construction, age of the structure, direction and strength of the wind.

The effectiveness of an envelope's ability to perform as expected depends on the;

Quality of workmanship and materials used.

The National Fenestration Rating Council (NFRC) energy performance label can help you determine how well a product will;

Reduce the building heat gain in the summer, reduce the building heat loss in the winter, keep out wind, and resist condensation.

Moisture control within the wall cavity is very important because wet or damp insulation has;

Reduced insulating value.

What will a non-uniform distribution from settling insulation in an attic cause?

Reduction in insulating value and effectiveness.

Which of the following is considered an Infiltration load?

Reduction in insulating value and effectiveness.

Local geography and microclimatic conditions often result in significant differences between;

Relative humidity and the wet bulb reports.

A simple thermostat controlling the air conditioner's functions senses;

Sensible heat.

Elevation changes greater than a few hundred feet can;

Significantly change the design conditions.

A window designed for sloped or horizontal installation in the roof of a residential building to provide day-lighting and/or ventilation and may be fixed or operable are called.

Skylight window.

When the outside temperature or wind speed changes;

The rate of heat loss or gain changes.

Which of the following best describes R-Value?

The rating of thermal resistance for a material. The higher the rating number the slower heat passes through it when the temperature difference is maintained across it.

Thermal conductivity is defined as;

The temperature at which a material will most efficiently conduct heat.

The R-value for building materials used in residential construction increases directly proportionate to the;

Thickness of the material.

Ventilation be important to the home owner because;

Too little ventilation may result in poor indoor air quality and/or unnecessary higher heating and cooling loads.

Radiant heat;

Travels outward from its source in straight lines at the speed of light.

What are heat Infiltration losses?

Uncontrolled outdoor air leaking into the occupied space from cracks and crevices through the building envelope during the cooling operation.