[NO GBP]Fixes space heaters. Makes their effectiveness independant of cell defines. (tgstation#84962)

## About The Pull Request
Makes BASE_HEATING_ENERGY be 40 KILO JOULES. It shouldn't have any
scaling with the cell defines because it impacts how powerful the space
heater interacts with the air, and doesn't impact how much energy is
actually used per energy it changed in the air.

Makes the efficiency variable inversely scale with STANDARD_CELL_CHARGE.
This makes the consumption relative to the standard cell charge, so
changing the defines won't impact how long the space heater lasts.

Makes the heating_energy var use initial() instead of the defines, so
they respect subtypes better. Makes the improvised chemical heater also
scale their variables based on the initial one. Also sets the improvised
chemical heater's settable_temperature_range to what it would be set to
with tier 1 parts in RefreshParts().

Renames chem_heating_power to beaker_conduction_power to more accurately
describe its effect of scaling how fast it heats or cools things.
Removes the pointless multiplication that is done to it in every
instance of using it, and instead just scale the variable down.

Gives a more accurate description of the improvised chemical heater's
heating power in its heating_examine().

Gives better feedback with balloon alerts when attempting to turn on a
space heater while it is lacking a cell, has no charge or is broken.
## Why It's Good For The Game
Closes tgstation#84892 

This will make their relative energy usage behave identical to before
the power changes. It will make their effectiveness independant of the
cell scale. Also the improvised chemical heater's heating power
description was misleading and nonsensical. Gives a more accurate one.
Space heaters give better feedback when attempting to turn it on while
it's missing a cell, has no charge or is broken.
## Changelog
:cl:
fix: Fixes space heater cell relative consumption inadvertently being
changed from the introduction of megacells.
qol: The improvised chemical heater gives a more accurate description of
its heating power on examine.
qol: Improved feedback when attempting to turn on a space heater that is
lacking a cell, has no charge or is broken.
code: Space heater relative cell consumption is consistent regardless of
the cell charge scale.
/:cl:

---------

Co-authored-by: SyncIt21 <[email protected]>

Author: Pickle-Coding

code/game/machinery/spaceheater.dm

@@ -2,7 +2,7 @@
 #define HEATER_MODE_HEAT "heat"
 #define HEATER_MODE_COOL "cool"
 #define HEATER_MODE_AUTO "auto"
-#define BASE_HEATING_ENERGY (STANDARD_CELL_RATE * 4)
+#define BASE_HEATING_ENERGY (40 KILO JOULES)
 
 /obj/machinery/space_heater
 	anchored = FALSE
@@ -32,7 +32,7 @@
 	///How much heat/cold we can deliver
 	var/heating_energy = BASE_HEATING_ENERGY
 	///How efficiently we can deliver that heat/cold (higher indicates less cell consumption)
-	var/efficiency = 200
+	var/efficiency = 20 MEGA JOULES / STANDARD_CELL_CHARGE
 	///The amount of degrees above and below the target temperature for us to change mode to heater or cooler
 	var/temperature_tolerance = 1
 	///What's the middle point of our settable temperature (30 °C)
@@ -176,7 +176,7 @@
 	for(var/datum/stock_part/capacitor/capacitor in component_parts)
 		cap += capacitor.tier
 
-	heating_energy = laser * BASE_HEATING_ENERGY
+	heating_energy = laser * initial(heating_energy)
 
 	settable_temperature_range = cap * initial(settable_temperature_range)
 	efficiency = (cap + 1) * initial(efficiency) * 0.5
@@ -295,7 +295,14 @@
 	on = !on
 	mode = HEATER_MODE_STANDBY
 	if(!isnull(user))
-		balloon_alert(user, "turned [on ? "on" : "off"]")
+		if(QDELETED(cell))
+			balloon_alert(user, "no cell!")
+		else if(!cell.charge())
+			balloon_alert(user, "no charge!")
+		else if(!is_operational)
+			balloon_alert(user, "not operational!")
+		else
+			balloon_alert(user, "turned [on ? "on" : "off"]")
 	update_appearance()
 	if(on)
 		SSair.start_processing_machine(src)
@@ -310,23 +317,29 @@
 	//We inherit the cell from the heater prior
 	cell = null
 	interaction_flags_click = FORBID_TELEKINESIS_REACH
+	display_panel = FALSE
+	settable_temperature_range = 50
 	///The beaker within the heater
 	var/obj/item/reagent_containers/beaker = null
-	///How powerful the heating is, upgrades with parts. (ala chem_heater.dm's method, basically the same level of heating, but this is restricted)
-	var/chem_heating_power = 1
-	display_panel = FALSE
+	/// How quickly it delivers heat to the reagents. In watts per joule of the thermal energy difference of the reagent from the temperature difference of the current and target temperatures.
+	var/beaker_conduction_power = 0.1
+	/// The subsystem we're being processed by.
+	var/datum/controller/subsystem/processing/our_subsystem
+
+/obj/machinery/space_heater/improvised_chem_heater/Initialize(mapload)
+	our_subsystem = locate(subsystem_type) in Master.subsystems
+	. = ..()
 
 /obj/machinery/space_heater/improvised_chem_heater/Destroy()
 	. = ..()
 	QDEL_NULL(beaker)
 
 /obj/machinery/space_heater/improvised_chem_heater/heating_examine()
 	. = ..()
-
-	var/power_mod = 0.1 * chem_heating_power
-	if(set_mode == HEATER_MODE_AUTO)
-		power_mod *= 0.5
-	. += span_notice("Heating power for beaker: <b>[display_power(heating_energy * power_mod, convert = TRUE)]</b>")
+	// Conducted energy per joule of thermal energy difference in a tick.
+	var/conduction_energy = beaker_conduction_power * (set_mode == HEATER_MODE_AUTO ? 0.5 : 1) * our_subsystem.wait / (1 SECONDS)
+	// This accounts for the timestep inaccuracy.
+	. += span_notice("Reagent conduction power: <b>[conduction_energy < 1 ? display_power(-log(1 - conduction_energy) SECONDS / our_subsystem.wait, convert = FALSE) : "∞W"]/J</b>")
 
 /obj/machinery/space_heater/improvised_chem_heater/toggle_power(user)
 	. = ..()
@@ -341,18 +354,18 @@
 		return PROCESS_KILL
 
 	if(beaker.reagents.total_volume)
-		var/power_mod = 0.1 * chem_heating_power
+		var/conduction_modifier = beaker_conduction_power
 		switch(set_mode)
 			if(HEATER_MODE_AUTO)
-				power_mod *= 0.5
+				conduction_modifier *= 0.5
 			if(HEATER_MODE_HEAT)
 				if(target_temperature < beaker.reagents.chem_temp)
 					return
 			if(HEATER_MODE_COOL)
 				if(target_temperature > beaker.reagents.chem_temp)
 					return
 
-		var/required_energy = abs(target_temperature - beaker.reagents.chem_temp) * power_mod * seconds_per_tick * beaker.reagents.heat_capacity()
+		var/required_energy = abs(target_temperature - beaker.reagents.chem_temp) * conduction_modifier * seconds_per_tick * beaker.reagents.heat_capacity()
 		required_energy = min(required_energy, heating_energy, cell.charge * efficiency)
 		if(required_energy < 1)
 			return
@@ -468,16 +481,17 @@
 	for(var/datum/stock_part/capacitor/capacitor in component_parts)
 		capacitors_rating += capacitor.tier
 
-	heating_energy = lasers_rating * BASE_HEATING_ENERGY
+	heating_energy = lasers_rating * initial(heating_energy)
 
-	settable_temperature_range = capacitors_rating * 50 //-20 - 80 at base
-	efficiency = (capacitors_rating + 1) * 10
+	settable_temperature_range = capacitors_rating * initial(settable_temperature_range) //-20 - 80 at base
+	efficiency = (capacitors_rating + 1) * initial(efficiency) * 0.5
 
 	target_temperature = clamp(target_temperature,
 		max(settable_temperature_median - settable_temperature_range, TCMB),
 		settable_temperature_median + settable_temperature_range)
 
-	chem_heating_power = efficiency / 20
+	// No time integration is used, so we should clamp this to prevent being able to overshoot if there was a subtype with a high initial value.
+	beaker_conduction_power = min((capacitors_rating + 1) * 0.5 * initial(beaker_conduction_power), 1 SECONDS / our_subsystem.wait)
 
 #undef HEATER_MODE_STANDBY
 #undef HEATER_MODE_HEAT