Method ventilationCalc

src/isomodel/SimModel.cpp:1263–1483

  */
  }
  void SimModel::ventilationCalc(const Vector& v_Th_avg, const Vector& v_Tc_avg, double frac_hrs_wk_day, Vector& v_Hve_ht, Vector& v_Hve_cl) const {
    double vent_zone_height = std::max(0.1, structure->buildingHeight());
    double qv_supp = ventilation->supplyRate() / structure->floorArea() / 3.6;
    double qv_ext = -(qv_supp - ventilation->supplyDifference() / structure->floorArea() / 3.6);
    double qv_comb = 0;
    double qv_diff = qv_supp + qv_ext + qv_comb;
    double vent_ht_recov = ventilation->heatRecoveryEfficiency();
    double vent_outdoor_frac = 1 - ventilation->exhaustAirRecirculated();
    double tot_env_A = sum(structure->wallArea()) + sum(structure->windowArea());
    /*

  %%  Ventilation
% required energy for mechanical ventilation based on  source EN ISO 13789
% C.3, C.5 and EN 15242:2007 6.7 and EN ISO 13790 Sec 9.2

vent_zone_height=max(0.1, In.stories*In.ftof);  % Ventilztion Zone Height (m) with a minimum of 0.1 m

qv_supp=In.vent_supply_rate./In.cond_flr_area./3.6;   %vent_supply_rate m3/h/m2 (input is in in L/s)
qv_ext=-(qv_supp-In.vent_supply_diff./In.cond_flr_area./3.6);   %vent exhaust rate m3/h/m2, negative indicates out of building

qv_comb = 0 ; % combustion appliance ventilation rate  - not implemented yet but will be impt for restaurants
qv_diff=qv_supp + qv_ext + qv_comb;  % difference between air intake and air exhaust including combustion exhaust

vent_ht_recov=In.vent_heat_recovery; %vent_heat_recovery_eff
vent_outdoor_frac=1-In.vent_recirc_fraction; % fctrl_vent_recirculation

% infilatration source EN 15242:2007 Sec 6.7 direct method
tot_env_A=sum(In.wall_area)+sum(In.win_area);
*/
    double n_p_exp = 0.65;
    /// \todo Note: v_Q75pa, aka infiltrationRate(), is never being calculated or set, so it is, at least in some cases, a
    ///             random value (now that the matrices are properly initialized to 0). So when it goes to 0, the rest
    ///             of the model goes to infinity for the HVAC calculations.
    ///             I'm setting it to non-zero here
    double v_Q75pa = structure->infiltrationRate();
    if (v_Q75pa == 0) {
      v_Q75pa = 0.00000000001;  // this might be a vestige of the rmeove of the "epsilon" code in the translator
    }

    double floorArea = structure->floorArea();
    double v_Q4pa = v_Q75pa * tot_env_A / floorArea * (std::pow((4.0 / 75.0), n_p_exp));

#ifdef DEBUG_ISO_MODEL_SIMULATION
    LOG(Trace, "v_Q4pa " << v_Q4pa << " v_Q75pa " << v_Q75pa << " tot_env_A " << tot_env_A << " floorArea: " << floorArea << " n_p_exp " << n_p_exp);
#endif

    double n_zone_frac = 0.7;
    double h_stack = n_zone_frac * vent_zone_height;
    double n_stack_exp = 0.667;  //% reset the pressure exponent to 0.667 for this part of the calc
    double n_stack_coeff = 0.0146;
    Vector dbtDiff = dif(location->weather()->mdbt(), v_Th_avg);
    printVector("dbtDiff", dbtDiff);
    Vector dbtDiffAbs = abs(dbtDiff);
    printVector("dbtDiffAbs", dbtDiffAbs);
    Vector dbtHStack = mult(dbtDiffAbs, h_stack);
    printVector("dbtHstack", dbtHStack);
    Vector dbtPowered = pow(dbtHStack, n_stack_exp);
    printVector("dbtPowered", dbtPowered);