Heat Loss and Heat Gain Flashcards
What is the purpose of the air conditioning system?
Provide high level of comfort to the occupants.
What are the six principles that must be addressed when selecting an air conditioning system for the house
Temperature.
Humidity.
Ventilation.
Filtration.
Circulation.
Noise.
Why is it important to complete a heat loss calculation.
The heat loss calculation will determine the equipment sizing requirements that will have a direct impact on providing the appropriate amount of heat to maintain the designed temperature.
How does the transfer of heat happen?
Always from the hotter spot to colder spot.
What is the result of under sizing heating appliance.
Undersized furnace will not keep up with the heating load.
What is the result of oversized heating appliance.
Result in poor temperature control and excessive operating costs.
What is heat?
Heat is a form of energy that flows between two bodies due to their difference in temperature.
Temperature will always travel from hot to col until both temperatures are the same
What four factors affect the building environment.
Building envelope,
Mechanical systems
Occupants
Appliances.
Name elements of the building envelope.
Exterior walls
Foundations
Roofs
Ceilings
Floors,
Windows
Doors,
Vapour barrier.
What are the three losses reduced by building envelope
Radiative,
Conductive
Convective
What is a mechanical system
Force used to maintain the in-balance between indoor and outdoor conditions.
How many BTUH and WH a human generate
250BTUH and 73WH
Does solar adjustment affect the Delta T
Yes
Conduction
Direct contact with another object.
Convection
Medium through liquid or gas
Radiation
Electromagnetic waves
Which have the greatest heat transfer (2)
Windows and doors.
How can heat losses be caused by the mechanical system
Duct passing through unconditioned spaces.
Ventilation air.
How can you describe Effective temperature.
How a person feels at a set temperature.
Does air movement affect the temperature you feel?
Yes
A higher RH (Relative humidity) will cause you to feel warmer.
Yes
What does design temperature reference to ?
Both indoor and outdoor temperature requirements for design.
At the outside winter design temperature, required heating equipment shall be capable of no less than?
72f (22c) in all living spaces.
65f (18c) in all unfurnished basement.
59f (15c) in all heated crawlspaces.
ABC refer use the January 2.5 % values for winter design conditions.
Design temperature difference is ?
Difference between indoor and outdoor design differences. 96F
Room by room loads is the most accurate way to calculate heat losses.
How would you describe Thermal Resistance (R-Value)
Heat flow through an object in a specific amount of time.
Below grade walls are ?
More than 2feet below grade level.
Loose
1950 to 1960
Average
1960 to 1980
Tight
1980 to Present.
What is the pick-up and set back factor
add 10% to heat losses calculation.
What affect heat gains
Solar Radiation
Mass Effect.
Internal Gains
Latent heat factors.
Heat gains for
Human
Kitchen
Laundry
Human 250 BTUH
Kitchen 1600 BTUH
Laundry 1200 BTUH but not considered if located in a basement.
Method to calculate heat gain and heat loss
Whole House.
Floor-by-floor
Room-by-room
ABC states that the design indoor temperature for summer shall be of a maximum of?
75f or 24c
Describe mass effect.
Radiant heat from direct sunlight will add an additional load on the building or rooms in the building. As building material are heated by the sun the absorb this heat energy, causing their temperature to rise dramatically.
Solar Radiation.
The total amount of heat in the building materials and surrounding air temp will the outdoor design temp difference differently for sunny and shaded areas.
