DERIV Subroutine

private subroutine DERIV(TempIndiceNum, Temp, TempChange)

Arguments

Type	Attributes		Name
integer		::	TempIndiceNum
real(kind=r64),	DIMENSION(2)	::	Temp
real(kind=r64),	DIMENSION(2)	::	TempChange
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DERIV
Source Code

SUBROUTINE DERIV(TempIndiceNum,Temp,TempChange)

          ! SUBROUTINE INFORMATION:
          !     AUTHOR         Jaewook Lee
          !     DATE WRITTEN   January 2000
          !     MODIFIED       Rick Strand (for E+ implementation February 2000)
          !     RE-ENGINEERED  na

          ! PURPOSE OF THIS SUBROUTINE:
          ! THIS SUBROUTINE CALCULATES HEAT TRANSFER TERMS INVOLVED IN THE
          ! THERMOREGULATORY SYSTEM TO OBTAIN THE RATES OF CHANGE OF CoreTemp & SkinTemp
          ! VIZ., CoreTempChange/TempChange & SkinTempChange/TempChange RESPECTIVELY.

          ! METHODOLOGY EMPLOYED:
          ! This subroutine is based heavily upon the work performed by Dan Maloney for
          ! the BLAST program.  Many of the equations are based on the original Pierce
          ! development.  See documentation for further details and references.

          ! REFERENCES:
          ! Maloney, Dan, M.S. Thesis, University of Illinois at Urbana-Champaign

          ! USE STATEMENTS:
          ! na

  IMPLICIT NONE    ! Enforce explicit typing of all variables in this routine

          ! SUBROUTINE ARGUMENT DEFINITIONS:
  INTEGER :: TempIndiceNum        ! Number of temperature indices  unused1208
  REAL(r64), DIMENSION(2) :: Temp       ! Temperature unused1208
  REAL(r64), DIMENSION(2) :: TempChange ! Change of temperature

          ! SUBROUTINE PARAMETER DEFINITIONS:
          ! na

          ! INTERFACE BLOCK SPECIFICATIONS:
          ! na

          ! DERIVED TYPE DEFINITIONS:
          ! na

          ! SUBROUTINE LOCAL VARIABLE DECLARATIONS:
  REAL(r64) :: ActLevelTot             ! Total activity level
  REAL(r64) :: CoreSignalShiv          ! Core signal when shivering occurs
  REAL(r64) :: CoreSignalShivMax       ! Maximum value of core signal when shivering occurs
  REAL(r64) :: CoreSignalSkinSens      ! The sensitivity of the skin signal increases
  REAL(r64) :: CoreSignalSweatMax      ! Maximum value of core signal when sweating occurs
  REAL(r64) :: CoreSignalSweatWarm     ! Core signal when sweating occurs
  REAL(r64) :: CoreTempSweat           ! Core temperature when sweating occurs
  REAL(r64) :: CoreSignalWarm          ! Warm core signal
  REAL(r64) :: CoreSignalWarmMax       ! Maximum value of warm core signal
  REAL(r64) :: EvapHeatLossDrySweat    ! Evaporative heat loss by sweating when total skin wettedness < 0.4
  REAL(r64) :: Err                     ! Stop criteria for iteration
  REAL(r64) :: ErrPrev                 ! Previous value of stop criteria for iteration
  REAL(r64) :: EvapHeatLossSweatEst    ! Estimated evaporative heat loss by sweating
  REAL(r64) :: EvapHeatLossSweatEstNew ! New value of estimated evaporative heat loss by sweating
  REAL(r64) :: IntHeatProdTot          ! Total internal heat production
  REAL(r64) :: SkinCndctMax            ! Maximum value of skin conductance
  REAL(r64) :: SkinSignalCold          ! Cold skin signal
  REAL(r64) :: SkinSignalColdMax       ! Maximum value of cold skin signal
  REAL(r64) :: SkinSignalSweatCold     ! Cold skin signal for sweat inhibition
  REAL(r64) :: SkinSignalSweatColdMax  ! Maximum value of cold skin signal for sweat inhibition
  REAL(r64) :: SkinCndctDilation       ! Overall skin conductance due to vasodilation
  REAL(r64) :: SkinCndctConstriction   ! Overall skin conductance due to vasoconstriction
  REAL(r64) :: SkinSignalShiv          ! Skin signal when shivering occurs
  REAL(r64) :: SkinSignalShivMax       ! Maximum value of skin signal when shivering occurs
  REAL(r64) :: SkinSignalSweatMax      ! Skin signal when sweating occurs
  REAL(r64) :: SkinSignalSweatWarm     ! Maximum value of skin signal when sweating occurs
  REAL(r64) :: SkinSignalWarm          ! Warm skin signal
  REAL(r64) :: SkinSignalWarmMax       ! Maximum value of warm skin signal
  REAL(r64) :: SkinTempSweat           ! Skin temperature when sweating occurs
  REAL(r64) :: SkinWetSignal           ! Skin wettedness signal
  REAL(r64) :: SweatCtrlFac            ! Sweat control factor
  REAL(r64) :: SweatSuppFac            ! Sweat suppression factor due to skin wettedness
  REAL(r64) :: WeighFac                ! Weighting factor of core siganl

  ! THE CONTROLLING SYSTEM.
  ! THE CONTROLLING SIGNALS :
  ! SIGNALS FOR KS.
  CoreSignalWarm = CoreTemp - 36.98d0
  SkinSignalWarm = SkinTemp - 33.8d0
  SkinSignalCold = 32.1d0 - SkinTemp
  CoreSignalSkinSens = CoreTemp - 35.15d0
  CoreSignalWarmMax = MAX(0.d0,CoreSignalWarm)
  SkinSignalWarmMax = MAX(0.d0,SkinSignalWarm)
  SkinSignalColdMax = MAX(0.d0,SkinSignalCold)

  ! SIGNALS FOR EvapHeatLossSweat.
  CoreTempSweat = CoreTemp
  IF(CoreTempSweat > 38.29d0) CoreTempSweat = 38.29d0
  CoreSignalSweatWarm = CoreTempSweat - CoreTempNeut
  SkinTempSweat = SkinTemp
  IF(SkinTempSweat > 36.1d0) SkinTempSweat = 36.1d0
  SkinSignalSweatWarm = SkinTempSweat - SkinTempNeut
  CoreSignalSweatMax = MAX(0.d0,CoreSignalSweatWarm)
  SkinSignalSweatMax = MAX(0.d0,SkinSignalSweatWarm)
  SkinSignalSweatCold = 33.37d0 - SkinTemp
  IF(SkinTempNeut < 33.37d0) SkinSignalSweatCold = SkinTempNeut - SkinTemp
  SkinSignalSweatColdMax = MAX(0.d0,SkinSignalSweatCold)

  ! SIGNALS FOR SHIVERING.
  CoreSignalShiv = 36.9d0 - CoreTemp
  SkinSignalShiv = 32.5d0 - SkinTemp
  CoreSignalShivMax = MAX(0.d0,CoreSignalShiv)
  SkinSignalShivMax = MAX(0.d0,SkinSignalShiv)

  ! CONTROLLING FUNCTIONS :
  ! SHIVERING RESPONSE IN W/M**2.
  ShivResponse = 20.d0*CoreSignalShivMax*SkinSignalShivMax + 5.d0*SkinSignalShivMax
  IF(CoreTemp >= 37.1d0) ShivResponse = 0.0d0

  ! SWEAT FUNCTION IN W/M**2.
  WeighFac = 260.d0+70.d0*AcclPattern
  SweatCtrlFac = 1.d0 + 0.05d0*SkinSignalSweatColdMax**2.4d0

  ! EvapHeatLossDrySweat = SWEAT WHEN SkinWetTot < 0.4.
  EvapHeatLossDrySweat = ((WeighFac*CoreSignalSweatMax + 0.1d0*WeighFac*SkinSignalSweatMax) &
                         *EXP(SkinSignalSweatMax/8.5d0))/SweatCtrlFac

  ! MAXIMUM EVAPORATIVE POWER, EvapHeatLossMax, IN W/M**2.
  SkinVapPress = CalcSatVapPressFromTemp(SkinTemp)
  EvapHeatLossMax = 2.2d0*Hc*(SkinVapPress - VapPress)*CloPermeatEff
  IF(EvapHeatLossMax > 0.0d0) THEN
    SkinWetSweat = EvapHeatLossDrySweat/EvapHeatLossMax
    EvapHeatLossDiff = 0.408d0*(SkinVapPress - VapPress)
    EvapHeatLoss = SkinWetSweat*EvapHeatLossMax+(1.d0 - SkinWetSweat)*EvapHeatLossDiff
    SkinWetTot = EvapHeatLoss/EvapHeatLossMax
    IF(Time == 0.0d0) THEN
      EvapHeatLossSweat = EvapHeatLossDrySweat
      EvapHeatLossSweatPrev = EvapHeatLossDrySweat
    END IF
    IF(SkinWetTot > 0.4d0) THEN

  ! ITERATION  FOR SWEAT WHEN SkinWetTot IS GREATER THAT 0.4.
      IterNum = 0
      IF(SkinWetSweat > 1.0d0) SkinWetSweat = 1.d0
      DO
        EvapHeatLossSweatEst = EvapHeatLossSweatPrev
        SkinWetSweat = EvapHeatLossSweatEst/EvapHeatLossMax

        IF(SkinWetSweat > 1.0d0) SkinWetSweat = 1.d0

        EvapHeatLossDiff = 0.408d0*(SkinVapPress - VapPress)
        EvapHeatLoss = (1.d0 - SkinWetTot)*EvapHeatLossDiff + EvapHeatLossSweat
        SkinWetTot = EvapHeatLoss/EvapHeatLossMax

        IF(SkinWetTot > 1.0d0) SkinWetTot = 1.d0

        SkinWetSignal = MAX(0.d0,SkinWetTot - .4d0)
        SweatSuppFac = 0.5d0 + 0.5d0*EXP(-5.6d0*SkinWetSignal)
        EvapHeatLossSweatEstNew = SweatSuppFac*EvapHeatLossDrySweat

        IF(IterNum == 0) EvapHeatLossSweat = EvapHeatLossSweatEstNew

        Err = EvapHeatLossSweatEst - EvapHeatLossSweatEstNew

        IF (IterNum /= 0) THEN
          IF((ErrPrev*Err) < 0.0d0) EvapHeatLossSweat = (EvapHeatLossSweatEst + EvapHeatLossSweatEstNew)/2.0d0
          IF((ErrPrev*Err) >= 0.0d0) EvapHeatLossSweat = EvapHeatLossSweatEstNew
        END IF

  ! STOP CRITERION FOR THE ITERATION.
        IF((ABS(Err) <= 0.5d0) .OR. (IterNum >= 10)) EXIT
        IterNum = IterNum + 1
        EvapHeatLossSweatPrev = EvapHeatLossSweat
        ErrPrev = Err

      END DO

    ELSE
      EvapHeatLossSweat = EvapHeatLossDrySweat
    END IF

  ELSE
    SkinWetSweat = 1.d0
    SkinWetTot = 1.d0
    EvapHeatLossSweat = 0.5d0*EvapHeatLossDrySweat
    EvapHeatLoss = EvapHeatLossSweat
  END IF

  ! OVERALL SKIN CONDUCTANCE, KS, IN W/M**2/C.
  ! SkinCndctDilation = EFFECT DUE TO VASODILATION.
  ! SkinCndctConstriction = EFFECT DUE TO VASOCONSTRICTION.
  SkinCndctDilation = 42.45d0*CoreSignalWarmMax + 8.15d0*CoreSignalSkinSens**0.8d0*SkinSignalWarmMax
  SkinCndctConstriction = 1.0d0 + 0.4d0*SkinSignalColdMax
  ! ThermCndct IS EQUIVALENT TO KS
  ThermCndct = 5.3d0+(6.75d0+SkinCndctDilation)/SkinCndctConstriction
  SkinCndctMax = 75.d0+10.d0*AcclPattern
  IF(ThermCndct > SkinCndctMax) ThermCndct = SkinCndctMax

  ! PASSIVE ENERGY BALANCE EQUATIONS.
  ! TOTAL METABOLIC HEAT PRODUCTION RATE, ActLevel, IN W/M**2.
  ActLevelTot = ActLevel + ShivResponse
  IntHeatProdTot = ActLevelTot - WorkEff
  ! RESPIRATION HEAT LOSS, RespHeatLoss, IN W/M**0.
  LatRespHeatLoss = 0.0023d0*ActLevelTot*(44.d0 - VapPress)
  DryRespHeatLoss = 0.0014d0*ActLevelTot*(34.d0 - AirTemp)
  RespHeatLoss = LatRespHeatLoss + DryRespHeatLoss
  ! HEAT FLOW FROM CORE TO SKIN, HeatFlow, IN W/M**2.
  HeatFlow = ThermCndct*(CoreTemp - SkinTemp)
  ! TempChange(1) = CoreTempChange/TempChange, IN C/HR.
  TempChange(1) = (IntHeatProdTot - RespHeatLoss - HeatFlow)/CoreThermCap
  IF(EvapHeatLoss > EvapHeatLossMax) EvapHeatLoss = EvapHeatLossMax

  ! DRY HEAT EXCHANGE BY RADIATION & CONVECTION, R+C, IN W/M**2.
  DryHeatLoss = H*CloBodyRat*CloThermEff*(SkinTemp - OpTemp)
  ! TempChange(2) = SkinTempChange/TempChange, IN C/HR.
  TempChange(2) = (HeatFlow - EvapHeatLoss - DryHeatLoss)/SkinThermCap

  RETURN

END SUBROUTINE DERIV
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