Hydronics Flashcards
A normal adult generates in light activity generates how much heat?
400 BTUs per hour
A ton of cooling
The amount of cooling provided by melting 1 ton of ice within a 24-hr period
Heat capacity
The amount of energy needed to change the temperature of a material by a certain amount
Specific heat
The ratio of the heat capacity of a substance to the heat capacity of a standard substance at the same temperature.
Liquids - water
Gases - air
A given volume of water can absorb over ______ Times more heat as the same volume of air for the same temperature change.
3400
The overall hydronic system this consists of four interrelated subsystems:
- Heat Source
- Distribution System
- Heat Emitters
- Control System
Heat transfer equation
Q = (A/R)(🔺T)
Typically wood-framed walls will have from ____ to _____ of the walk areas solid framing across the insulation cavity. The lower range would be for ____ on-center framing and the higher for _____ on-center framing.
10-15%
24” with insulated headers over windows and doors
16” with solid headers
Supporting Copper Tubing Spacing
1/2” - 3/4”: 5 feet
1 - 1-1/4”: 6 feet
1-1/2” - 2” : 8 feet
Vertical: 10 feet
Equation for head produced by a pump
H = (144 *Pd)/D
Pd = pressure differential between inlet and outlet of pump D = density of fluid
Digital Input
an input which can only have one of two states; open or closed
Target vs. controlled variable
Target - Is the desired ideal status of the controlled variable
Controlled - usually actual reading of air temp, etc.
Error
Deviation between target and contolled variable
Three common types of processing algorithms:
(P) Proportional
(PI) Proportional-integral
(PID) Proportional-integral-derivative
Proportional Processing
the magnitude of the output signal depends only on the error between the target and measure values of the controlled variable - operates within a band range which ranges from zero to fill output.
