vault backup: 2025-10-08 18:16:15
This commit is contained in:
+20
-20
@@ -1,9 +1,29 @@
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{
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"recentFiles": [
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{
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"basename": "fire-alarm",
|
||||
"path": "fire-alarm.md"
|
||||
},
|
||||
{
|
||||
"basename": "hvac-calculations",
|
||||
"path": "hvac-calculations.md"
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||||
},
|
||||
{
|
||||
"basename": "alternating-current",
|
||||
"path": "alternating-current.md"
|
||||
},
|
||||
{
|
||||
"basename": "conductor-sizing",
|
||||
"path": "conductor-sizing.md"
|
||||
},
|
||||
{
|
||||
"basename": "full-takeoff",
|
||||
"path": "full-takeoff.md"
|
||||
},
|
||||
{
|
||||
"basename": "electrical",
|
||||
"path": "electrical.md"
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||||
},
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||||
{
|
||||
"basename": "README",
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||||
"path": "README.md"
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||||
@@ -12,14 +32,6 @@
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||||
"basename": "stochastic-branch-takeoff",
|
||||
"path": "stochastic-branch-takeoff.md"
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||||
},
|
||||
{
|
||||
"basename": "electrical",
|
||||
"path": "electrical.md"
|
||||
},
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||||
{
|
||||
"basename": "full-takeoff",
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||||
"path": "full-takeoff.md"
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||||
},
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{
|
||||
"basename": "nfpa-70_314_boxes",
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||||
"path": "nfpa-70_314_boxes.md"
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@@ -52,10 +64,6 @@
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||||
"basename": "nfpa-70_110_requirements-for-electrical-installations",
|
||||
"path": "nfpa-70_110_requirements-for-electrical-installations.md"
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||||
},
|
||||
{
|
||||
"basename": "alternating-current",
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||||
"path": "alternating-current.md"
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||||
},
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||||
{
|
||||
"basename": "construction-estimating",
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||||
"path": "construction-estimating.md"
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||||
@@ -191,14 +199,6 @@
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{
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||||
"basename": "functional-labor-factoring",
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"path": "functional-labor-factoring.md"
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||||
},
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||||
{
|
||||
"basename": "gold-plating",
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||||
"path": "gold-plating.md"
|
||||
},
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||||
{
|
||||
"basename": "functional-estimating",
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||||
"path": "functional-estimating.md"
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||||
}
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],
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"omittedPaths": [],
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+23
-31
@@ -36,27 +36,32 @@ The voltage measured between any line and neutral is called phase voltage.
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||||
208Y/120V
|
||||
480Y/277V
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||||
|
||||
In a 3-phase wye connected system,
|
||||
ignoring the difference in voltage,
|
||||
is voltage drop calculated differently
|
||||
between a line to line load and a line to neutral load
|
||||
|
||||
### Voltage Systems
|
||||
|
||||
120/240V 1-Phase 3-Wire:
|
||||
- 120V 1-Phase 2-Wire # Line to Neutral
|
||||
- 240V 1-Phase 2-Wire # Line to Line
|
||||
* 120V 1-Phase 2-Wire # Line to Neutral
|
||||
* 240V 1-Phase 2-Wire # Line to Line
|
||||
|
||||
120/208V 3-Phase 4-Wire:
|
||||
- 120V 1-Phase 2-Wire # Line to Neutral
|
||||
- 208V 1-Phase 2-Wire # Line to Line
|
||||
- 208V 3-Phase 3-Wire # Line to Lines
|
||||
* 120V 1-Phase 2-Wire # Line to Neutral
|
||||
* 208V 1-Phase 2-Wire # Line to Line
|
||||
* 208V 3-Phase 3-Wire # Line to Lines
|
||||
|
||||
277/480V 3-Phase 4-Wire:
|
||||
- 277V 1-Phase 2-Wire # Line to Neutral
|
||||
- 480V 1-Phase 2-Wire # Line to Line
|
||||
- 480V 3-Phase 3-Wire # Line to Lines
|
||||
* 277V 1-Phase 2-Wire # Line to Neutral
|
||||
* 480V 1-Phase 2-Wire # Line to Line
|
||||
* 480V 3-Phase 3-Wire # Line to Lines
|
||||
|
||||
wiring-configurations:
|
||||
- 1-Phase 2-Wire # Line to Neutral or Line to Line
|
||||
- 1-Phase 3-Wire # Line to Line and Line to Neutral
|
||||
- 3-Phase 3-Wire # Line to Lines
|
||||
- 3-Phase 4-Wire # Line to Lines and Line to Neutral
|
||||
* 1-Phase 2-Wire # Line to Neutral or Line to Line
|
||||
* 1-Phase 3-Wire # Line to Line and Line to Neutral
|
||||
* 3-Phase 3-Wire # Line to Lines
|
||||
* 3-Phase 4-Wire # Line to Lines and Line to Neutral
|
||||
|
||||
## Active and Reactive Power
|
||||
|
||||
@@ -65,27 +70,27 @@ and the electromagnetic "inertia" of inductance and capacitance,
|
||||
inherent of all matter,
|
||||
the power in an AC circuit is divided into two components:
|
||||
|
||||
- **Active Power**
|
||||
* **Active Power**
|
||||
(abbreviated $P$, measured in watts)
|
||||
also known as real power, is power that *does work*.
|
||||
also known as real power, is power that _does work_.
|
||||
|
||||
- **Reactive Power**
|
||||
* **Reactive Power**
|
||||
(abbreviated $Q$, measured in volt-amperes reactive (VAR))
|
||||
transfers no net energy to the load.
|
||||
|
||||
derived from these components are others:
|
||||
|
||||
- **Complex Power**
|
||||
* **Complex Power**
|
||||
(abbreviated $S$, measured in volt-amperes (VA))
|
||||
is the vector sum of the active and reactive components.
|
||||
It is "complex" because it exists on the real and imaginary axes
|
||||
of active and reactive power respectively.
|
||||
|
||||
- **Apparent Power**
|
||||
* **Apparent Power**
|
||||
(abbreviated $|S|$, measured in volt-amperes (VA))
|
||||
is the magnitude of the complex power vector.
|
||||
|
||||
- **Power Factor**
|
||||
* **Power Factor**
|
||||
(abbreviated $\text{PF}$, unitless)
|
||||
is the ratio of active power to apparent power.
|
||||
|
||||
@@ -97,16 +102,3 @@ $$
|
||||
|
||||
Capacitance and inductance can both be measured in VAR,
|
||||
but their effects cancel each other out rather than add.
|
||||
|
||||
## Motors
|
||||
|
||||
1hp = 746 watts
|
||||
|
||||
full-load current (FLC) / full-load amperes (FLA)
|
||||
|
||||
minimum circuit ampacity (MCA)
|
||||
|
||||
$$
|
||||
\text{MCA} = 1.25 \times \text{FLC}
|
||||
$$
|
||||
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+54
-26
@@ -116,28 +116,45 @@ either for spec requirements or conduit fill considerations.
|
||||
## Voltage Drop
|
||||
|
||||
$$
|
||||
V_d = I \times R \times L \times M
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||||
Z = R \cos(\theta) + X \sin(\theta)
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||||
$$
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||||
|
||||
where
|
||||
* $V_d$ = Voltage Drop in volts ($V$)
|
||||
* $I$ = Current in Amperes ($A$)
|
||||
* $R$ = Feeder linear resistance in ohms per foot ($VA^{-1}\text{ft}^{-1}$)
|
||||
* $Z$ = Effective impedance
|
||||
* $R$ = AC resistance
|
||||
* $X$ = Reactance
|
||||
* $\theta$ = Power factor angle = $\arccos(PF)$
|
||||
|
||||
> [!info] 1-Phase, Line to Neutral Voltage Drop
|
||||
>
|
||||
> $$
|
||||
> \Delta V_{LN} = I \times Z \times 2L
|
||||
> $$
|
||||
|
||||
> [!info] 1-Phase, Line to Line Voltage Drop
|
||||
>
|
||||
> $$
|
||||
> \Delta V_{LL} = \sqrt{3} \times I \times Z \times 2L
|
||||
> $$
|
||||
|
||||
> [!info] 3-Phase Voltage Drop
|
||||
>
|
||||
> $$
|
||||
> \Delta V_{3\phi} = \sqrt{3} \times I \times Z \times L
|
||||
> $$
|
||||
|
||||
where
|
||||
* $\Delta V$ = Voltage drop in volts ($V$)
|
||||
* $I$ = Current in amperes ($A$)
|
||||
* $L$ = Length of wire one way in feet ($\text{ft}$)
|
||||
* $M$ = Multiplier
|
||||
* $2$ for 1-phase
|
||||
* $\sqrt{3}$ for 3-phase
|
||||
|
||||
It is often more useful to know the maximum length
|
||||
a certain wiring configuration is suitable for.
|
||||
|
||||
$$
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||||
L = \frac{ V_d }{ I \times M } \times \frac{1}{R}
|
||||
L = \frac{ \Delta V }{ I \times M } \times \frac{1}{Z}
|
||||
$$
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||||
|
||||
* $L$ = Max length of wire one way in feet ($\text{ft}$)
|
||||
* $\frac{ V_d }{ I \times M }$ = Max circuit resistance in ohms ($VA^{-1}$)
|
||||
|
||||
> [!info] Ohm's Law
|
||||
>
|
||||
> $$
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||||
@@ -148,6 +165,24 @@ $$
|
||||
> "Current" is not the OCPD rating,
|
||||
> but the actual load.
|
||||
|
||||
## Parallel Runs
|
||||
|
||||
The equivalent resistance of parallel resistances is given by
|
||||
|
||||
$$
|
||||
\frac{1}{R_{\text{eq}}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + \dots
|
||||
$$
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||||
|
||||
For $P$ parallel resistances of value $R$
|
||||
|
||||
$$
|
||||
\begin{align*}
|
||||
\frac{1}{R_{\text{eq}}} &= P \times \left(\frac{1}{R}\right) \\
|
||||
&= \frac{P}{R} \\
|
||||
R_{\text{eq}} &= \frac{R}{P}
|
||||
\end{align*}
|
||||
$$
|
||||
|
||||
## Transformers
|
||||
|
||||
$$
|
||||
@@ -159,21 +194,14 @@ $$
|
||||
* $V$ = feeder voltage
|
||||
* $E$ = efficiency
|
||||
|
||||
## Parallel Runs
|
||||
## Motors
|
||||
|
||||
1 electric horsepower = 746 watts
|
||||
|
||||
full-load current (FLC) / full-load amperes (FLA)
|
||||
|
||||
minimum circuit ampacity (MCA)
|
||||
|
||||
$$
|
||||
\frac{1}{R_{\text{eq}}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + \dots
|
||||
\text{MCA} = 1.25 \times \text{FLC}
|
||||
$$
|
||||
|
||||
where $R_1 = R_n$:
|
||||
|
||||
$$
|
||||
\begin{align*}
|
||||
\frac{1}{R_{\text{eq}}} &= P \times \left(\frac{1}{R_1}\right) \\
|
||||
&= \frac{P}{R_1} \\
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||||
R_{\text{eq}} &= \frac{R_1}{P}
|
||||
\end{align*}
|
||||
$$
|
||||
|
||||
where
|
||||
* $P$ = Number of parallel runs
|
||||
|
||||
@@ -52,6 +52,9 @@ Wiring devices and their wall plates are a common target of [[gold-plating]].
|
||||
|
||||
Unit condensing units
|
||||
|
||||
Put homeruns on the `Area` of the dwelling unit.
|
||||
Put connections on the `Area` of the CU.
|
||||
|
||||
.../`CONDENSOR HOME RUNS`
|
||||
|
||||
.../`CU CONDENSER SLEEVE W/ FLEX - NO HMRN WIRE`
|
||||
|
||||
+30
-16
@@ -9,6 +9,13 @@ tags:
|
||||
|
||||
## Info
|
||||
|
||||
### Fire Command Center (FCC)
|
||||
|
||||
> [!info] Also Known As
|
||||
> Emergency Command Center (ECC)
|
||||
> Fire Alarm Command Center (FACC)
|
||||
> Fire Alarm Command Room (FACR)
|
||||
|
||||
## Sequence
|
||||
|
||||
### 1. Preparation
|
||||
@@ -26,19 +33,24 @@ tags:
|
||||
|
||||
### 2. Takeoff
|
||||
|
||||
#### Fire Command Center
|
||||
#### Backbone
|
||||
|
||||
Put all backbone takeoff in the `Area` of the Fire Command Center.
|
||||
Include [[sleeving]] as necessary.
|
||||
|
||||
##### Fire Command Center
|
||||
|
||||
`COMMON ASSEMBLIES`/`FIRE ALARM & DAS SYSTEMS`/`HEAD END EQUIP`/`... HEAD END`
|
||||
|
||||
#### Generator Room
|
||||
##### Generator Room
|
||||
|
||||
`COMMON ASSEMBLIES`/`FIRE ALARM & DAS SYSTEMS`/`GEN, ELEV, FIRE PUMP & FA ROOM ASSEMBLIES`/`GENERATOR ROOM ...`
|
||||
|
||||
#### Fire Pump Room
|
||||
##### Fire Pump Room
|
||||
|
||||
`COMMON ASSEMBLIES`/`FIRE ALARM & DAS SYSTEMS`/`GEN, ELEV, FIRE PUMP & FA ROOM ASSEMBLIES`/`FIRE PUMP ROOM ...`
|
||||
|
||||
#### FACR to Elevator Shafts
|
||||
##### FACR to Elevator Shafts
|
||||
|
||||
`COMMON ASSEMBLIES`/`FIRE ALARM & DAS SYSTEMS`/`GEN, ELEV, FIRE PUMP & FA ROOM ASSEMBLIES`/`ELEV SHAFT ...`
|
||||
|
||||
@@ -57,7 +69,7 @@ Input adder length to reach the bottom of the pit
|
||||
| | |
|
||||
```
|
||||
|
||||
#### FACR to Elevator Control Rooms
|
||||
##### FACR to Elevator Control Rooms
|
||||
|
||||
`COMMON ASSEMBLIES`/`FIRE ALARM & DAS SYSTEMS`/`GEN, ELEV, FIRE PUMP & FA ROOM ASSEMBLIES`/`ELEV CONTROL ROOM ...`
|
||||
|
||||
@@ -67,7 +79,7 @@ Input adder length to reach the bottom of the pit
|
||||
* Use Typicals for the vertical riser. (Ex// 10' per floor)
|
||||
* Add [[sleeving]] as necessary.
|
||||
|
||||
#### FACR to Stairwells
|
||||
##### FACR to Stairwells
|
||||
|
||||
This is for the Flow/Tamper modules in the stairwells
|
||||
|
||||
@@ -75,7 +87,7 @@ This is for the Flow/Tamper modules in the stairwells
|
||||
|
||||
* Measure from the furthest end of FACR to the furthest end of the stairwell to find length
|
||||
|
||||
#### Terminal Cabinets
|
||||
##### Terminal Cabinets
|
||||
|
||||
`COMMON ASSEMBLIES`/`FIRE ALARM & DAS SYSTEMS`/`TERMINAL CABINET`/`ACE D ACCESSORY CABINET ENCLOSURE (2) 2" ...`
|
||||
|
||||
@@ -89,7 +101,7 @@ Vertical:
|
||||
* Use 10ft Riser in Typical
|
||||
* Add [[sleeving]] as necessary.
|
||||
|
||||
#### Annunciator Panels
|
||||
##### Annunciator Panels
|
||||
|
||||
> [!info] Also Known As
|
||||
> * Fire Alarm Annunciator (FAA)
|
||||
@@ -99,25 +111,27 @@ Vertical:
|
||||
|
||||
* Measure from the Fire Command Room to FAA or Lobby
|
||||
|
||||
#### Smoke Detectors
|
||||
#### Devices
|
||||
|
||||
##### Smoke Detectors
|
||||
|
||||
_Design Build:_
|
||||
Count every stairwell at every level.
|
||||
|
||||
#### Pull Stations
|
||||
##### Pull Stations
|
||||
|
||||
_Design Build:_
|
||||
Count every stairwell at every level
|
||||
and every exterior exit.
|
||||
|
||||
#### Flow-Tamper Switches
|
||||
##### Flow-Tamper Switches
|
||||
|
||||
No free air. if wood frame, take off as EMT.
|
||||
|
||||
_Design Build:_
|
||||
Count every stairwell at every level.
|
||||
|
||||
#### Magnetic Door Holders
|
||||
##### Magnetic Door Holders
|
||||
|
||||
`COMMON ASSEMBLIES`/`FIRE ALARM & DAS SYSTEMS`/`INDICATING DEVICES WITH WIRE - ...`/`MAGNETIC DOOR HOLDER - ...`
|
||||
|
||||
@@ -125,7 +139,7 @@ _Design Build:_
|
||||
Count every set of double doors.
|
||||
(Typical of elevator lobbies and corridors)
|
||||
|
||||
#### Speaker Strobes
|
||||
##### Speaker Strobes
|
||||
|
||||
_Design Build:_
|
||||
* Count every 75 ft,
|
||||
@@ -135,7 +149,7 @@ _Design Build:_
|
||||
* every elevator lobby,
|
||||
* and every BOH room on the first floor and garage levels.
|
||||
|
||||
#### Firefighter Phone System
|
||||
##### Firefighter Phone System
|
||||
|
||||
* firefighter phone jacks
|
||||
* fire warden station
|
||||
@@ -146,7 +160,7 @@ Not related to responder radio.
|
||||
|
||||
`COMMON ASSEMBLIES`/`FIRE ALARM & DAS SYSTEMS`/`COMMUNICATION DEVICES ...`/`...`
|
||||
|
||||
#### Fire Smoke Dampers (FSD's)
|
||||
##### Fire Smoke Dampers (FSD's)
|
||||
|
||||
Take off both FA
|
||||
|
||||
@@ -158,4 +172,4 @@ and Electrical
|
||||
|
||||
### 3. Review
|
||||
|
||||
* Sleeving
|
||||
* [[sleeving]]
|
||||
|
||||
@@ -0,0 +1,89 @@
|
||||
---
|
||||
id:
|
||||
aliases: []
|
||||
tags: []
|
||||
---
|
||||
# HVAC Calculations
|
||||
|
||||
## Units
|
||||
|
||||
### British Thermal Unit
|
||||
|
||||
Unit of heat energy
|
||||
|
||||
There are several definitions of the Btu,
|
||||
HVAC uses the IT definition,
|
||||
abbreviated Btu<sub>IT</sub>
|
||||
|
||||
$$
|
||||
\begin{align*}
|
||||
1 \text{Btu}_\text{IT} &= \left( 4.1868 \times 453.59237 \times{\frac{5}{9}} \right) \text{J} \\
|
||||
&\approx 1055.056 \text{J}
|
||||
\end{align*}
|
||||
$$
|
||||
|
||||
More common than Btu itself is
|
||||
thousand British thermal units per hour (MBH),
|
||||
a unit of power.
|
||||
|
||||
$$
|
||||
\begin{align*}
|
||||
1 \text{MBH} &= 1000 \text{Btu/hr} \\
|
||||
&\approx 3.412 \text{W}
|
||||
\end{align*}
|
||||
$$
|
||||
|
||||
### Ton of Refrigeration (TR or TOR)
|
||||
|
||||
Unit of power
|
||||
|
||||
> [!info] Also Known As
|
||||
> * refrigeration ton (RT)
|
||||
> * ton (refrigeration)
|
||||
|
||||
$$
|
||||
\begin{align*}
|
||||
1 \text{TR} &= 12000 \text{Btu}_\text{IT}/\text{h} \\
|
||||
&\approx 3516.853 \text{W}
|
||||
\end{align*}
|
||||
$$
|
||||
|
||||
### Cubic Feet per Minute (CFM)
|
||||
|
||||
Unit of volumetric flow
|
||||
|
||||
## Measures
|
||||
|
||||
### Airflow
|
||||
|
||||
* CFM
|
||||
|
||||
External static pressure (ESP)
|
||||
measured in inches of water
|
||||
|
||||
### Heating/Cooling Capacity
|
||||
|
||||
* Tons (refrigeration)
|
||||
* MBH
|
||||
|
||||
Entering air temperature (EAT)
|
||||
Leaving air temperature (LAT)
|
||||
Mixed air temperature (MAT)
|
||||
|
||||
Latent heat
|
||||
Sensible heat
|
||||
|
||||
Sensible -> dry bulb
|
||||
Latent -> wet bulb
|
||||
|
||||
#### ???
|
||||
|
||||
OSA EAT (F)
|
||||
EXH EAT (F)
|
||||
|
||||
IN S.L.
|
||||
OUT ALT.
|
||||
|
||||
### Efficiency
|
||||
|
||||
* η (eta)
|
||||
Reference in New Issue
Block a user