MANAGEMENT AND CONTROLS WITH
COMPLETE SOLUTIONS
Define Thermal Energy - ANSWER-Energy associated with the movement of molecules
and measured as heat
Define Electrical Energy - ANSWER-Energy associated with the flow of negatively
charged electrons through a conductive medium.
Define Mechanical Energy - ANSWER-The sum of kinetic and potential energy. Kinetic
being the energy of motion, potential being stored energy.
Define BTU - ANSWER-Quantity of heat possessed by an object is measured in BTU. It
is the amount of heat required to raise temp of one pound of pure water one degree F at
sea level.
What is the fundamental law of heat transfer? - ANSWER-heat always flows from an
object that is warmer to an object that is cooler.
What are the three factors affecting amount and rate of heat flow through a building
envelope? - ANSWER-1. Total surface area
2. Temperature differences
3. Material properties.
What are the four factors uses to evaluate the materials that form a building enevlope? -
ANSWER-1. Thermal Conductivity
2. Thermal Conductance
3. Thermal Resistance
4. Overall Coefficient of heat transfer
What is thermal conductivity? - ANSWER-The measurement of a materials ability to
conduct heat.
What is thermal conductance? - ANSWER-A measure of the rate of heat flow through a
material or air space.
What is thermal resistance? - ANSWER-A materials ability to retard heat flow.
,What is the overall coefficient of heat transfer? - ANSWER-Resistance value of all
building materials, air spaces, including walls, ceilings and surface air films.
What happens when heat is added to a substance? - ANSWER-It's molecular motion
increases.
What is temperature? - ANSWER-The measurement of the intensity of heat.
What does a BTU measure? - ANSWER-The quantity of heat.
What is sensible heat? - ANSWER-heat that when added to or removed from a
substance it changes the temperature of the substance
What is specific heat? - ANSWER-The ratio of the temperature it takes to raise the
temperature of a substance 1 degree to the amount of heat it takes to raise a pound of
pure water 1 degree.
What is the formula for determining the amount of heat required to change the
temperature of a substance without changing the substances state? - ANSWER-Heat
required in BTU - weight in LB X specific heat X temp change in degrees F.
What is latent heat? - ANSWER-Heat that when added or removed from a substance
changes that substances state, but not its temperature.
What are the standard terms used to describe the change of a substance from one state
to another through the absorption or release of latent heat? - ANSWER-solid to liquid:
melting
liquid to solid: fusion
liquid to gas: vaporization
gas to liquid: condensation
What are the three basic processes of heat transfer? - ANSWER-Conduction,
Convection, Radiation
What is conduction? - ANSWER-Heat transfer through matter, molecule to molecule,
due to temp difference
What is convection? - ANSWER-Heat transfer through fluid, typically air or water
What is radiation? - ANSWER-Heat transfer through electromagnetic waves
What is scale formation? - ANSWER-mineral deposits on a metal surface that have
precipitated out of a solution
What happens to a boiler with excessive scaling? - ANSWER-Reduced steam output,
excessive fuel use, increase in stack temp.
, What should be done to the feedwater treatment if scale is present? - ANSWER-modify
schedule and/or add chemicals.
What else can be done to reduce scale? - ANSWER-Use blowdown controls.
What aspects of building design to climate conditions influence? - ANSWER-
Orientation, configuration, envelope, energy requirements, illumination, heating, HVAC
requirements.
What climatic conditions affect buildings energy use? - ANSWER-Temperature
variation, quality of sunlight, wind velocity and direction, and snowfall
What is EUI - ANSWER-Energy use index. Measured in BTU, how much energy a
building uses per gross conditioned sq. ft. of space per period of time, typically one
year.
What is the primary use of EUI? - ANSWER-Compare a buildings energy use from one
period of time to another.
How are heating degree days determined? - ANSWER-Compare outdoor mean temp
per 24hr period to a base of 65 degrees.
How are cooling degree days dermined - ANSWER-Compare outdoor mean temp per
24hr period to a base of 75 degrees.
Why is degree-day data essential? - ANSWER-When comparing EUI data, a difference
in degree days may be the cause of a different EUI from one year to another.
Where can electrical energy data be found? - ANSWER-Utility records.
How can oil consumption be calculated? - ANSWER-Determine amount of oil required
to refill tank.
Explain natural gas data and how natural gas consumption is measured. - ANSWER-
Natural gas is measured in therms and the data is consumption + all taxes and fees.
What are some solar controls that are used to reduce heat losses and gains caused by
windows? - ANSWER-Curtains, awnings, tinted glass, reflective films.
What does heat absorbing glass do? - ANSWER-reduces solar radiation, transmission
without substantially reducing visibility
What type of glass should be used in buildings with long cooling seasons? - ANSWER-
reflective glass