Heat Loss And Heat Gain Flashcards
What do heat loss and heat gain calculations ensure?
Correct selection of equipment in order to provide comfort for the occupant
What is the purpose of an air conditioning system
To Provide a high level of comfort to the home owner
What are the 6 principles of comfort
Temperature, humidity, ventilation, filtration, circulation, noise
What are the results of an undersized furnace
Won’t keep up with heating load
What are the results of an oversized furnace
Poor temperature control and excessive operating costs
What can happen after the equipment size is determined from the heat loss calculation
Duct design can be done
Describe heat
Form of energy that flows between two bodies due to their difference in temperature
Which direction does heat travel
Hot to cold
What does 1 watt and 1 kw equal in BTUH
1 watt 3.41 BTUH
1kw 3412 BTUH
Building environments are effected by what 4 factors
Building envelope, mechanical systems, appliances and occupants
What separates the interior of a building from the outdoor environment
Building envelope
What minimizes the heat lost or heat gained to the structure
Materials with high resistance and good vapour barriers
Heat will continue to flow until a balance is reached
T or F
True
What is the mechanical system used for
Maintaining the in-balance between indoor and outdoor conditions
What does the mechanical system control
The temperature, air motion, humidification, filtration, exhaust and fresh air
How do occupants control the mechanical systems and effect indoor climate
Opening and closing doors and windows and by using appliances
How much heat to occupants generate approximately
250 BTUH (73 W) per person
Air movement both inside and outside can affect the indoor climate
T or F
True
What are air change rates reliant on to minimize leakage
Mechanical systems
As leakage rates are reduced the need for___________and________ increases ?
Fresh air and exhausting of stale contaminated air
How does air pressure flow
Higher pressure to an area of lower pressure
What happens when a mechanical systems creates a low pressure within the building envelope
Higher pressure air on the exterior of the building envelope will flow inward through cracks and openings
What effects do wind speed increases have on a building
Undesirable leakage which results in undesirable drafts and adds loads in either heat loss or gains for the building and its systems
In Canada what guidelines do we need to follow or exceed
NBC (National Building Code)
What guidelines do we follow in Alberta
(ABC) Alberta building code
How is conduction accomplished
Through direct contact with another object
What’s is a current in a liquid or gas that transfers heat by moving molecules from a warmer area to a cooler area ?
Convection
What is transmitted through electromagnetic waves, which transfer heat from a hotter object to colder object,
Radiation
Does cold air enter a building to lower the indoor temperature ?
No, heat travels outside to heat the outdoor temperature
What is a buildings greatest heat loss
Windows and doors
What are the two ways heat is lost by the mechanical system
Ducts passing through unconditioned spaces
Ventilation air (fresh air and exhaust)
What is effective temperature?
How a person feels at a set temperature
How is air temperature controlled in a home
Thermostat
Air movement effects the temperature you feel
T or F
True
What device measures relative humidity?
Higrometer
A higher relative humidity percentage causes you to feel warmer
T OR f
True
What is the relative humidity of a room that’s 72 degrees Fahrenheit (22 c )
55%
At the outside winter design temperature, required heating equipment shall be capable of maintaining an indoor air temperature no less than________?
72 •F (22 •C) in all living spaces
65 •F (18 •C) in unfinished basements
59 •F (15 •C) in heated crawl spaces
Building codes set temperature for outside design
T or F
TRUE
What outside design temperature is used in Alberta
January at 2.5% values for winter design conditions
Walls that are common to an attached garage must be treated as ?
Exposed
What is the most accurate method of load calculation
Room by room loads
What is thermal resistance ( R-Value)
Heat flow through an object in a specific amount of time
The insulation value must match the wall value
T or F
True
What are below grade walls ?
Walls that are more than 2’ below grade
Ducts passing through unheated spaces will have losses even if they are insulated
T or F
True
Are heat gain calculations required for below grade walls and crawl spaces?
No
Building materials are heated by the sun and absorb heat energy causing a dramatic temperature rise, what is this called?
MASS EFFECT
Do all locations in Alberta and most of Canada require solar adjustment
Yes
