Building Utilities 2: Midterms Reviewer part 1 Flashcards
What are the three methods of heat transfer
Radiation, convection and conduction
heat travels as waves through space in the same manner that light travels
Radiation
It is when heat travels through liquids or gases
Convection
It is when heat moves through a solid material;
The denser the material, the better is will transfer heat
Conduction
The difference between the amount of heat on the inside of a building compared to the outside is known as?
heat loss or heat gain
It is defined as the heat lost through openings in a building
Infiltration
It is the ability of a material or component to resist heat transfer
Resistivity
It is needed to determine the
effectiveness of building materials and components in transmitting or
blocking the transmission of heat
Measurement standard for heat levels
It is the standard unit of measurement for heat
British Thermal Units (BTU)
the amount of heat needed to raise the temperature of 1 pound
of water 1 degree Fahrenheit, at a constant pressure of 1 atmosphere
(air pressure at sea level)
British Thermal Units (BTU)
The standard metric unit for heat
Joules (J)
BTU to joules
multiply the BTU value by 1055
uniform method of rating the resistance of heat flow through building materials
R-value
T or F: The lower the R number, the greater the resistance to heat flow
False
Should be higher R value
T or F: When building materials are combined in layers, the sum of their R-
values is the total R-value for the component
True
Please memorize this
It accurately indicates the combined thermal conductivity of all materials in a structure, including air spaces
U-value
T or F: Does lower R-values and low U values indicate greater efficiency?
False
Should be higher R-value
T or F: R-values of building materials vary
True
T or F: R-value increases as the thickness of any material is increased..
True
T or F: Windows and doors account for most heat loss in cold countries and heat gain in warm regions
True
They reflect heat energy (invisible solar radiation) yet transmit visible light
Low-emissivity coatings (low-E)
T or F: Heat flows through windows in both directions, through radiation, convection and infiltration (air leakage) only
False
Lacking “conduction”
Applied between the panes to slow heat transfer in double windows (double glazing)
argon or krypton gas
– cracks around doors, windows and
fireplaces can allow all internal heat to escape in less than an hour
poorly constructed building
prevents heat loss/gain by using passive designs
Effective orientation and design
It is a significant deterrent to heat loss or heat gain’
Insulation
It is any material used to slow the transfer of heat; Retards the transfer of heat; Stops moisture, sound, fire and insect penetration
Insulation
T or F: HVAC systems work easier to overcome the loss of warm air or cool air
through walls, floors and ceilings without insulation
False: should be work harder
T or F: Proper wall and floor insulation reduce 25% of the heat transfer
True
T or F: Add Insulation with an area for ventilation to roofs as 10% of heat transfer is
through the roof
False, should be 40 %
It is an insulation outside and surround the structure
insulation envelope
These are non-reflective, plastic fabric sheets used to totally wrap the exterior and prevent air vapors and water from penetrating exterior walls
Vapor barrier films
Acts as a vapor barrier, the shiny side should face the inside of the building
Non-reflective foil sheets
Insulation commonly used for roof, wall and floor structural panels.
Foam core insulation
Insulation commonly used for columns, beams
Structural foam core insulated components
It is the amount of heat that passes through an exterior surface of a building
Heat loss or heat gain
Learn how to compute Heat loss
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It is when air is heated in a furnace
Warm-air systems
allow warm air to rise naturally without the use of fans; rarely used today
Gravity system
must be located on a level lower than the area to be heated; heating engine
Furnace
distribute the heated air to outlets throughout the building; can also be used by cooling systems
Air ducts
Air is blown through the ducts by a fan located in the heating or cooling device.
Forced air systems
It is when Cool air enters the top and warmed air exits the bottom
Downflow furncae
It is when cool air enters the bottom
Upflow furnace
It is when cool and warm air moves at the same level
Horizontal flow furnace
It utilizes distribution ducts or return ducts
Forced-air ducts
It brings cool air back to the furnace to be warmed
Return ducts
It is connected to a plenum chamber
Forced-air distribution ducts
It is an enclosed space located between the furnace and distribution ducts; Larger than any duct; Slows the flow of air through the ducts
Plenum chamber
T or F: ducts lead to floor/ceiling outlets at least one outlet for every 4.50m of exterior wall space for both heating and cooling
True
They vary in patterns and connects a furnace to outlets throughout
the building
Duct systems
separate ducts directly linked to the furnace or AC unit with each outlet; Provides well-balanced heat, but require more duct length
Individual duct system
Plenum size may be the same through its length; the same as the individual duct system but utilizes a plenum
Individual plenum system
It is when a perimeter duct is connected to a furnace with a feeder duct on each side; looped ducts
Perimeter loop system
All warm-air systems include room outlets or ____ on the floor, ceiling or
wall
Registers
These are enclosed space in which the air pressure is greater than it is outside (used by the early Romans)
Plenum
used as a sealed plenum chamber to distribute warm or cool air to floor registers in the rooms
Entire underfloor space (crawl space)
– include the location of:
▪ Furnace
▪ Outlet
▪ Duct
Forced-air system drawings
They are drawn in zones with a separate
furnace and ductwork system for each
Buildings requiring more than one furnace
The use of oil or gas boiler to heat water and a water pump to send the water to
radiators, finned tubes or convectors
HYDRONIC (HOT-WATER) UNITS
It provides even heat and are quiet and clean; Do not provide air filtration or circulation; Not compatible with cooling systems that require air ducts
Hydronic systems
It is the most common, most effective hydronic outlet type
Baseboard outlet
It provides hot water for sinks and showers, eliminating the need for a separate water heater unit
Domestic oil burners
Types of boiler units
Series-loop system, One-pipe system, Two-pipe system, Radiant system
A system with continual loop of pipes containing hot water
Series-loop system
Hot water flows
continually from the
Boiler through the
outlet units and back
again to the boiler
for reheating
Series-loop system
Heat is controlled
only at the source of
the loop
Series-loop system
– heated water is circulated through pipes that are connected to radiators or convectors by means of bypass pipes
One-pipe system
A system that Allows each radiator to be individually controlled by valves
▪ Water flows from one side of each radiator to the main line and returns to the boiler for reheating
One-pipe system;
has two parallel pipes
Two-pipe system
One pipe for the supply of hot water from the boiler to each radiator ; One pipe for the return of cooled water from each radiator to the boiler
Two-pipe system
distributes hot water through a series of continual pipes in floors and sometimes ceilings
Radiant system
Radiant system: not often because of the weight of the filled
Ceiling systems
Radiant system:– consists of pipes laid on a concrete base then
covered with a finished concrete slab
Radiant floor
Steam-heating unit operate from a boiler that makes steam
STEAM UNITS
It is transported by pipes to radiators or convectors and baseboards that
give off heat;
Steam
Condenses to water and returns to the boiler to reheated to steam; Functions on water vapor, not hot water
Steam
Are steam units Easy to install and maintain
Yes
It is delivered through either perimeter or radial systems
Steam heat
are steam units ideal for large apartments, commercial buildings, industrial
complexes with separate steam generation facilities
Yes
Produced when electricity passes through resistance wires; Heat is often radiated; Can be fan-blown (convection)
ELECTRIC HEAT
placed in panel heaters
Resistance wires
a device that automatically regulates temperature, or that activates a device when the temperature reaches a certain point.
thermostat
