COP calculation script

[juuzo]

Hi, I'm really new to lua scripting and I'm trying to make simple calculation program that calculates heatpump cop with measured temperatures, power and fan speed. Anyway I'm little stuck on this script. I get error
/home/pi/domoticz/scripts/lua/script_time_COP.lua:5: ']' expected near 'Fan'
So I assume that there is somethin wrong with fan speed reading. Fan speed is simple 6 step switch with values 0 to 60.

Code: Select all

commandArray = {}
time = os.date("*t")
if((time.min % 5)==0)then --Run every 5 minutes

   var1 = commandArray.GetValue(otherdevices_svalues[Heatpump Fan Speed],1)
   if (var1 == 0 or var1 == 10) then
   airvolume = 0
   end

   if (var1 == 20) then
   airvolume = 120
   end

   if (var1 == 30) then
   airvolume = 220
   end

   if (var1 == 40) then
   airvolume = 320
   end

   if (var1 == 50) then
   airvolume = 520
   end

   if (var1 == 60) then
   airvolume = 620
   end

   OutletTemp = commandArray.GetValue(otherdevices_svalues[Heatpump Outlet Temp],1)	
   InletTemp = commandArray.GetValue(otherdevices_svalues[Heatpump Inlet Temp],1)	
   inpower = commandArray.GetValue(otherdevices_svalues[Heatpump Power/Energy],1)	
   
   outpower = airvolume * 1,293 * 1,01 * (OutletTemp-InletTemp)
   
   calculation = outpower / inpower
   print( " ####Cop debug: "..calculation)
   
   COPidx = otherdevices_idx['Heatpump COP']
   commandArray['UpdateDevice'] = COPidx..'|0|'..calculation
end
return commandArray

[SweetPants]

Try var1 = commandArray.GetValue(otherdevices_svalues['Heatpump Fan Speed'],1)

[juuzo]

I got something to work with this script

Now I can read values even though my airflow doesn't update in those if then fields. Biggest problem is now that my energy meter gives values like 300.10;259999 where first value is power what I want and second is energy what I don't need. How do I parse that first number and how can I convert it to float? I have tried tonumber() command but it doesn't work.

Code: Select all

local airvolume = 10
commandArray = {}
time = os.date("*t")
if((time.min % 1)==0)then --Run every 5 minutes

   var1 = otherdevices['Heatpump Fan Speed']
   if var1 == 0 or var1 == 1 then
   airvolume = 0
   end

   if var1 == 2 then
   airvolume = 120
   end

   if var1 == 3 then
   airvolume = 220
   end

   if var1 == 4 then
   airvolume = 320
   end

   if var1 == 5 then
   airvolume = 520
   end

   if var1 == 6 then
   airvolume = 620
   end
   print( " ####Fan read: "..var1)
   print( " ####Airvolume: "..airvolume)
   OutletTemp = otherdevices_svalues['Heatpump Outlet Temp']
   InletTemp = otherdevices_svalues['Heatpump Inlet Temp']
   inpower = tonumber(otherdevices_svalues['Heatpump Power/Energy'])	
   print( " ####Outlet temp: "..OutletTemp)
   print( " ####Inlet temp: "..InletTemp)
   print( " ####Power: "..inpower)
   
   outpower = 300*1.293*1.01*(OutletTemp-InletTemp)
   print( " ####Outpower: "..outpower)
   calculation = outpower / inpower
   print( " ####Cop debug: "..calculation)
   
   COPidx = otherdevices_idx['Heatpump COP']
   commandArray['UpdateDevice'] = COPidx..'|0|'..calculation
end
return commandArray

[juuzo]

Ok Now I got it work. Required some try and error methods. Here's the working script with some other additions.

Code: Select all

local debug = "1" -- Debug on = 1, off = 0
COPidx = otherdevices_idx['Heatpump COP']
commandArray = {}
time = os.date("*t")
if((time.min % 2)==0)then --Run every 2 minutes
	if otherdevices['Heatpump Mode'] == "Heat" then
		OutletTemp = otherdevices_svalues['Heatpump Outlet Temp']
		InletTemp = otherdevices_svalues['Heatpump Inlet Temp']
		inpower, energy = otherdevices_svalues['Heatpump Power/Energy']:match("([^;]+)")	
		var1 = otherdevices['Heatpump Fan Speed']
			if var1 == "Auto" then
				airvolume = 0  --If fan is in Auto mode, air flow could not be determined
			elseif var1 == "1" then
				airvolume = 406.80  --Fan speed 1 means 406.80m3/h air flow
			elseif var1 == "2" then
				airvolume = 475.80  --Fan speed 1 means 475.80m3/h air flow
			elseif var1 == "3" then
				airvolume = 684.60  --Fan speed 1 means 684.60m3/h air flow
			elseif var1 == "4" then
				airvolume = 900.00  --Fan speed 1 means 900.00m3/h air flow
			elseif var1 == "5" then
				airvolume = 954.60  --Fan speed 1 means 954.60m3/h air flow
			else
				print("####Ivalid FAN Speed") --If fan speed could not be read it is invalid and program terminated
				return 
			end
		inpowercompare = tonumber(string.format("%." .. (2) .. "f", inpower))
		if inpowercompare > 165 then --Panasonic minimum input power in Heat mode
			outpower = (OutletTemp-InletTemp)*airvolume*0.94*1.293*1.01--Assume that there is 6% error in air volume(0.96), 1.293 constant air density, 1.01 specific heat capacity for air
			outpowercompare = tonumber(string.format("%." .. (2) .. "f", outpower))
			if outpower > 0 then 
				rawcop = outpower/(inpower/1000*3600) --inpower*3600, power consumption in hour
				cop = tonumber(string.format("%." .. (2) .. "f", rawcop))
			else
				print( "####Outpower negative, Heapump de-ice?...")
				return
			end
		else
			print( "####Inpower too low, Heapump COP calculation not updated...")
			return 
		end
		if (debug == "1") then
			print( " ####Fan read: "..var1)
			print( " ####Airvolume: "..airvolume)
			print( " ####Outlet temp: "..OutletTemp)
			print( " ####Inlet temp: "..InletTemp)
			print( " ####Power: "..inpower)
			print( " ####Outpower: "..outpower)
			print( " ####Raw Cop calculation: "..rawcop)
			print( " ####Cop: "..cop)
		end
		if cop < 12 then
			if cop > -0.01 then
				commandArray['UpdateDevice'] = COPidx..'|0|'..cop
				print( "####Heatpump COP updated")
			else
				print ( "####COP too low, Heapump COP calculation not updated...")
			end
		else
			print( "####COP too high, Heapump COP calculation not updated...")
		end
	else
		print( "####Heatpump not in Heat mode...")
	end
end
return commandArray

[juuzo]

I tested this scrip yesterday and noticed that I need some kind of averaging for this script. Have to resolve that next.

[Derik]

Dear...
Can you please tell me what airflow meter you have?
A china one?
What hardware do you use?
And where is the place you put the flowmeter?