<?xml version="1.0" encoding="UTF-8"?>
<!--
Copyright (c) 2015 onox
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
-->
<system name="c172p heat">
<property value="37.0">heat/human-body-temp-degc</property>
<channel name="cabin-doors-windows">
<aerosurface_scale name="heat/door-left">
<input>/sim/model/door-positions/leftDoor/position-norm</input>
<zero_centered>false</zero_centered>
<domain>
<min>0.5</min>
<max>1.0</max>
</domain>
<range>
<min>0.0</min>
<max>1.0</max>
</range>
<clipto>
<min>0.0</min>
<max>1.0</max>
</clipto>
</aerosurface_scale>
<aerosurface_scale name="heat/door-right">
<input>/sim/model/door-positions/rightDoor/position-norm</input>
<zero_centered>false</zero_centered>
<domain>
<min>0.5</min>
<max>1.0</max>
</domain>
<range>
<min>0.0</min>
<max>1.0</max>
</range>
<clipto>
<min>0.0</min>
<max>1.0</max>
</clipto>
</aerosurface_scale>
<aerosurface_scale name="heat/door-baggage">
<input>/sim/model/door-positions/baggageDoor/position-norm</input>
<zero_centered>false</zero_centered>
<domain>
<min>0.0</min>
<max>1.0</max>
</domain>
<range>
<min>0.0</min>
<max>0.5</max>
</range>
<clipto>
<min>0.0</min>
<max>0.5</max>
</clipto>
</aerosurface_scale>
<aerosurface_scale name="heat/window-left">
<input>/sim/model/door-positions/leftWindow/position-norm</input>
<zero_centered>false</zero_centered>
<domain>
<min>0.5</min>
<max>1.0</max>
</domain>
<range>
<min>0.0</min>
<max>0.2</max>
</range>
<clipto>
<min>0.0</min>
<max>0.2</max>
</clipto>
</aerosurface_scale>
<aerosurface_scale name="heat/window-right">
<input>/sim/model/door-positions/rightWindow/position-norm</input>
<zero_centered>false</zero_centered>
<domain>
<min>0.5</min>
<max>1.0</max>
</domain>
<range>
<min>0.0</min>
<max>0.2</max>
</range>
<clipto>
<min>0.0</min>
<max>0.2</max>
</clipto>
</aerosurface_scale>
<summer name="heat/doors-windows-left">
<input>heat/door-left</input>
<input>heat/window-left</input>
<clipto>
<min>0.0</min>
<max>1.0</max>
</clipto>
</summer>
<summer name="heat/doors-windows-right">
<input>heat/door-right</input>
<input>heat/window-right</input>
<clipto>
<min>0.0</min>
<max>1.0</max>
</clipto>
</summer>
<summer name="heat/doors-windows-total">
<input>heat/doors-windows-left</input>
<input>heat/doors-windows-right</input>
<input>heat/door-baggage</input>
</summer>
<summer name="heat/humans-count">
<input>/pax/pilot/present</input>
<input>/pax/co-pilot/present</input>
<input>/pax/left-passenger/present</input>
<input>/pax/right-passenger/present</input>
</summer>
</channel>
<channel name="cabin-temperature">
<!-- The exhaust gas temperature controls how much the air is
heated up.
-->
<pure_gain name="heat/heat-exhaust-gas-temp-degc">
<input>/engines/active-engine/egt-norm</input>
<!-- Extra heat (in Celsius) when EGT is at maximum. EGT is
usually between 0.4 and 0.6.
-->
<gain>60.0</gain>
</pure_gain>
<!-- Computes the difference in temperature between the cabin
heat intake (behind propeller) and the cabin.
-->
<summer name="heat/cabin-heat-temp-diff">
<input>/environment/temperature-degc</input>
<input>-heat/cabin-air-temp-degc</input>
<input>heat/heat-exhaust-gas-temp-degc</input>
</summer>
<!-- Computes the difference in temperature between the cabin
air intake (ventilating air door on the right side of the
fuselage) and the cabin.
-->
<summer name="heat/cabin-air-temp-diff">
<input>/environment/temperature-degc</input>
<input>-heat/cabin-air-temp-degc</input>
</summer>
<summer name="heat/cabin-human-temp-diff">
<input>heat/human-body-temp-degc</input>
<input>-heat/cabin-air-temp-degc</input>
<clipto>
<min>-0.01</min>
<max> 0.10</max>
</clipto>
</summer>
<scheduled_gain name="heat/cabin-air-transfer-heat-duct">
<input>heat/cabin-heat-temp-diff</input>
<gain>/environment/aircraft-effects/cabin-heat-set</gain>
<table>
<independentVar lookup="row">/engines/active-engine/rpm</independentVar>
<independentVar lookup="column">/velocities/airspeed-kt</independentVar>
<tableData>
40 120
0 0.10 0.50
700 0.25 0.60
2800 0.50 1.00
</tableData>
</table>
</scheduled_gain>
<scheduled_gain name="heat/cabin-air-transfer-air-duct">
<input>heat/cabin-air-temp-diff</input>
<gain>/environment/aircraft-effects/cabin-air-set</gain>
<table>
<independentVar lookup="row">/engines/active-engine/rpm</independentVar>
<independentVar lookup="column">/velocities/airspeed-kt</independentVar>
<tableData>
40 120
0 0.10 0.50
700 0.25 0.60
2800 0.50 1.00
</tableData>
</table>
</scheduled_gain>
<!-- Even with the air slider closed, there is still some small
amount of heat transferred via the fuselage.
-->
<summer name="heat/cabin-air-transfer-fuselage">
<input>/environment/temperature-degc</input>
<input>-heat/cabin-air-temp-degc</input>
<clipto>
<min>-0.1</min>
<max> 0.1</max>
</clipto>
</summer>
<scheduled_gain name="heat/cabin-air-transfer-overhead-vent-left">
<input>heat/cabin-air-temp-diff</input>
<gain>/controls/climate-control/overhead-vent-front-left</gain>
<table>
<independentVar>/velocities/airspeed-kt</independentVar>
<tableData>
40 0.10
120 0.50
</tableData>
</table>
</scheduled_gain>
<scheduled_gain name="heat/cabin-air-transfer-overhead-vent-right">
<input>heat/cabin-air-temp-diff</input>
<gain>/controls/climate-control/overhead-vent-front-right</gain>
<table>
<independentVar>/velocities/airspeed-kt</independentVar>
<tableData>
40 0.10
120 0.50
</tableData>
</table>
</scheduled_gain>
<pure_gain name="heat/cabin-air-transfer-doors-windows">
<input>heat/cabin-air-temp-diff</input>
<gain>heat/doors-windows-total</gain>
</pure_gain>
<pure_gain name="heat/cabin-air-transfer-humans">
<input>heat/cabin-human-temp-diff</input>
<gain>heat/humans-count</gain>
</pure_gain>
<summer name="heat/cabin-air-transfer-total">
<input>heat/cabin-air-transfer-heat-duct</input>
<input>heat/cabin-air-transfer-air-duct</input>
<input>heat/cabin-air-transfer-fuselage</input>
<input>heat/cabin-air-transfer-overhead-vent-left</input>
<input>heat/cabin-air-transfer-overhead-vent-right</input>
<input>heat/cabin-air-transfer-doors-windows</input>
<input>heat/cabin-air-transfer-humans</input>
</summer>
<integrator name="heat/cabin-air-temp-degc">
<input>heat/cabin-air-transfer-total</input>
<!-- This is the constant that actually controls how fast
(or slow) the cabin temperature changes.
-->
<c1>0.030</c1>
</integrator>
</channel>
<channel name="surface-temperature">
<summer name="heat/surface-cabin-heat-transfer">
<input>heat/cabin-air-temp-degc</input>
<input>-heat/surface-temp-degc</input>
<!-- If the pilot opens the air slider, the cabin air temp might
start increasing or decreasing fast. Clip the difference to
limit this effect.
-->
<clipto>
<min>-5.0</min>
<max> 5.0</max>
</clipto>
</summer>
<integrator name="heat/surface-temp-degc">
<input>heat/surface-cabin-heat-transfer</input>
<!-- This is the constant that actually controls how fast
(or slow) the surface temperature changes.
-->
<c1>0.020</c1>
</integrator>
</channel>
<channel name="cabin-dewpoint">
<fcs_function name="heat/non-humans-airflow">
<function>
<quotient>
<sum>
<abs>
<property>heat/cabin-air-transfer-air-duct</property>
</abs>
<abs>
<product>
<quotient>
<property>heat/cabin-air-transfer-heat-duct</property>
<property>heat/cabin-heat-temp-diff</property>
</quotient>
<property>heat/cabin-air-temp-diff</property>
</product>
</abs>
<abs>
<property>heat/cabin-air-transfer-doors-windows</property>
</abs>
<abs>
<property>heat/cabin-air-transfer-overhead-vent-left</property>
</abs>
<abs>
<property>heat/cabin-air-transfer-overhead-vent-right</property>
</abs>
</sum>
<abs>
<property>heat/cabin-air-temp-diff</property>
</abs>
</quotient>
</function>
</fcs_function>
<pure_gain name="heat/humans-airflow">
<input>heat/humans-count</input>
<gain>0.1</gain>
</pure_gain>
<fcs_function name="heat/future-cabin-rel-humidity">
<function>
<quotient>
<sum>
<product>
<property>heat/non-humans-airflow</property>
<property>/environment/relative-humidity</property>
</product>
<product>
<property>heat/humans-airflow</property>
<!-- Human breath: 35 C with 95 % RH -->
<value>95.0</value>
</product>
</sum>
<sum>
<property>heat/non-humans-airflow</property>
<property>heat/humans-airflow</property>
</sum>
</quotient>
</function>
</fcs_function>
<summer name="heat/cabin-rel-humidity-diff">
<input>heat/future-cabin-rel-humidity</input>
<input>-heat/cabin-relative-humidity</input>
<clipto>
<min>-10.0</min>
<max> 10.0</max>
</clipto>
</summer>
<integrator name="heat/cabin-relative-humidity">
<input>heat/cabin-rel-humidity-diff</input>
<!-- This is the constant that actually controls how fast
(or slow) the cabin relative humidity changes.
-->
<c1>0.015</c1>
<!-- Keep relative humidity above zero to prevent
math domain error (which happens in ln(x) for x = 0).
-->
<clipto>
<min> 0.1</min>
<max>100.0</max>
</clipto>
</integrator>
<!-- Computing the dewpoint using the Arden Buck equation:
y_m(T, RH) = ln(RH/100 * exp((b - T/d) * (T/(c+T)))
using the following constants:
b = 17.67; c = 243.5 celsius; d = 234.5 celsius
from:
Bolton, D. (1980). The computation of equivalent potential
temperature. Monthly weather review, 108(7), 1046-1053.
-->
<fcs_function name="heat/cabin-dewpoint-ym">
<function>
<ln>
<product>
<quotient>
<property>heat/cabin-relative-humidity</property>
<value>100.0</value>
</quotient>
<exp>
<product>
<difference>
<value>17.67</value>
<quotient>
<property>heat/cabin-air-temp-degc</property>
<value>234.5</value>
</quotient>
</difference>
<quotient>
<property>heat/cabin-air-temp-degc</property>
<sum>
<value>243.5</value>
<property>heat/cabin-air-temp-degc</property>
</sum>
</quotient>
</product>
</exp>
</product>
</ln>
</function>
</fcs_function>
<!-- Computing dewpoint using the Arden Buck equation using constants
that give a maximum error of 0.1 % for -30.0 <= T <= +35.0.
Reference: https://en.wikipedia.org/wiki/Dew_point#Calculating_the_dew_point
-->
<fcs_function name="heat/cabin-dewpoint-degc">
<function>
<quotient>
<product>
<value>243.5</value>
<property>heat/cabin-dewpoint-ym</property>
</product>
<difference>
<value>17.67</value>
<property>heat/cabin-dewpoint-ym</property>
</difference>
</quotient>
</function>
</fcs_function>
<!-- Normalized human perception of dew point:
0.0 is dry; 0.1 - 0.5 is comfortable; 0.7 is somewhat uncomfortable;
0.8 - 0.9 is very uncomfortable; 1.0 is extremely high.
Reference: https://en.wikipedia.org/wiki/Dew_point#Relationship_to_human_comfort
-->
<fcs_function name="heat/cabin-dewpoint-perception-norm">
<function>
<table>
<independentVar>heat/cabin-dewpoint-degc</independentVar>
<tableData>
10 0.0
13 0.3
16 0.5
18 0.7
21 0.8
24 0.9
26 1.0
</tableData>
</table>
</function>
</fcs_function>
</channel>
<channel name="fog-and-frost">
<summer name="heat/surface-dewpoint-diff">
<input>heat/cabin-dewpoint-degc</input>
<input>-heat/surface-temp-degc</input>
<!-- Small maximum to slowdown increase and decrease of fog
and frost.
-->
<clipto>
<min>-0.5</min>
<max> 0.5</max>
</clipto>
</summer>
<switch name="heat/moisture-windup-trigger">
<default value="0"/>
<test logic="AND" value="1">
heat/surface-dewpoint-diff GT 0
heat/moisture-norm GE 1
</test>
<test logic="AND" value="1">
heat/surface-dewpoint-diff LT 0
heat/moisture-norm LE 0
</test>
</switch>
<integrator name="heat/moisture-norm">
<input>heat/surface-dewpoint-diff</input>
<trigger>heat/moisture-windup-trigger</trigger>
<!-- This is the constant that actually controls how fast
(or slow) the moisture changes.
-->
<c1>0.010</c1>
<clipto>
<min>0.0</min>
<max>1.0</max>
</clipto>
</integrator>
<pure_gain name="heat/moisture-fog-level">
<input>heat/moisture-norm</input>
<gain>1.6</gain>
</pure_gain>
<pure_gain name="heat/moisture-frost-level">
<input>heat/moisture-norm</input>
<gain>1.0</gain>
</pure_gain>
<switch name="heat/fog-level">
<default value="heat/moisture-fog-level"/>
<test logic="AND" value="0">
heat/cabin-air-temp-degc LE 0
</test>
</switch>
<switch name="heat/frost-level">
<default value="heat/moisture-frost-level"/>
<test logic="AND" value="0">
heat/cabin-air-temp-degc GT 0
</test>
</switch>
</channel>
</system>