DWHR calc refinements

Added wr_dTDrain

Author: chipbarnaby

src/CNCULT.CPP

@@ -1832,7 +1832,8 @@ CULT( "wrDHWSYS",    DAT,   DHWHEATREC_OWNTI,  NO_INP|RDFLIN,0,0,  TYREF, &WSiB,
 CULT( "wrMult",		 DAT,	DHWHEATREC_MULT,   0,        0, VEOI,  TYSI,  0,      1,      N,   N),
 CULT( "wrType",	     DAT,	DHWHEATREC_TYPE,   0,        0, VEOI,  TYCH,  0,      C_DWHRTYCH_VERT, N,   N),
 CULT( "wrConfig",    DAT,	DHWHEATREC_CONFIG, 0,        0, VEOI,  TYCH,  0,      C_DWHRCFGCH_EQUAL, N,   N),
-CULT( "wrCSARatedEF",DAT,	DHWHEATREC_EFFRATED, RQD,    0, VHRLY, TYFL,  0,      .5f,    N,   N),
+CULT( "wrCSARatedEF",DAT,	DHWHEATREC_EFFRATED,RQD,     0, VHRLY, TYFL,  0,      .5f,    N,   N),
+CULT( "wrDTDrain",   DAT,   DHWHEATREC_DTDRAIN, 0,       0, VHRLY, TYFL,  0,     4.6f,    N,   N),
 CULT( "wrFxServed",  DAT,	DHWHEATREC_FXSERVED,0,       0, VEOI,  TYSI,  0,      1,      N,   N),
 CULT( "wrHWEndUse",	 DAT,	DHWHEATREC_HWENDUSE,0,       0, VEOI,  TYCH,  0,      C_DHWEUCH_SHOWER, N,   N),
 CULT( "endDHWHEATREC",  ENDER, 0,              0,        0, 0,     0,     0,      0,      N,   N),

src/CNRECS.DEF

@@ -3327,6 +3327,8 @@ RECORD DHWSYS "DHWSys" *RAT		// input / runtime DHW system
   *declare "DHWMTR* ws_pWHhwMtr; DHWMTR* ws_pFXhwMtr;"	// resolved DHWMTR pointers
 
 						// mixed and hot water use for this DHWSYS (w/o ws_mult)
+  *h *e FLOAT ws_whUseNoHR;				// current hour virtual hot water use w/o heat recovery, gal
+										//    re verification / accounting of DWHR results
   *h *e *nest DHWMTR_IVL ws_fxUseMix	// current hour total (mixed) water use at fixtures, gal
   *h    *nest DHWMTR_IVL ws_fxUseMixLH	// prior hour total (mixed) water use at fixtures, gal
   *h *e *nest DHWMTR_IVL ws_whUse		// current hour hot water use (at ws_tUse), gal
@@ -3582,6 +3584,9 @@ RECORD DHWHEATREC "DHWHeatRec" *RAT	// input / runtime drain water heat recovery
 
   *h FRAC wr_effRated			// rated effectiveness (generally CSA rating value)
 
+  *h FLOAT wr_dTDrain			// water temp drop from fixture use to drain, F
+								//    td = tUse - dTDrain;  default = 4.6 F
+						
   *s *e FLOAT wr_eff			// effectiveness under current conditions
 
   *r FLOAT wr_fWeight			// weighting factor for results

src/DHWCalc.cpp

@@ -683,14 +683,18 @@ RC DHWSYS::ws_DoHour(		// hourly calcs
 	//   wdu_DoHour accums add'l DHWDAYUSE draws to these values
 	ws_fxUseMix.wmt_AccumEU( 0, hwUseX);
 	ws_whUse.wmt_AccumEU( 0, hwUseX);
+	ws_whUseNoHR = ws_whUse.total;
 
 	DHWDAYUSE* pWDU = WduR.GetAtSafe( ws_dayUsei);	// ref'd DHWDAYUSE can vary daily
 	if (pWDU)
 	{	// accumulation DHWDAYUSE input to tick bins and total use
 		rc |= pWDU->wdu_DoHour( this);		// accum DAYUSEs
+		ws_whUseNoHR = ws_whUse.total;		// more added in ws_DoDWHR()
 		if (ws_wrCount && ws_iTk0DWHR < ws_iTkNDWHR)
 			rc |= ws_DoDWHR();		// modify tick values re DWHR
 	}
+	else
+		ws_whUseNoHR = ws_whUse.total;
 
 	if (!ws_HasCentralDHWSYS())
 	{	DHWSYS* pWSChild;
@@ -700,11 +704,6 @@ RC DHWSYS::ws_DoHour(		// hourly calcs
 		}
 	}
 
-#if 0
-	ws_fxUseMix.wmt_Finalize();
-	ws_whUse.wmt_Finalize();
-#endif
-
 #if defined( _DEBUG)
 	// check: compare tick totals to full hour values
 	float whUseSum = 0.f;
@@ -855,21 +854,24 @@ RC DHWSYS::ws_DoDWHR()
 {
 	RC rc = RCOK;
 
+#if 0
+	if (Top.jDay == 91 && Top.iHr == 20)
+		printf( "\nHit");
+#endif
+
 	// loop ticks that could include DWHR draws
 	// ws_qDWHR = 0.f; ... in ws_DoHour
 	double qRWHSum = 0.;
-	double whUseTot = 0.;	// hour total hot water use, gal
-	double whUseTotNoHR = 0.;	// check value: hour total hot water use w/o HR, gal
-	double tHotFXAvg = 0.;
+	// ws_whUseNoHR = 0.;		// check value: hour total hot water use w/o HR, gal
+								//  init'd by caller
 	int nTk = Top.tp_NHrTicks();
-	int nWarmup = 0;
 	for (int iTk=0; iTk < nTk; iTk++)
 	{	DHWTICK& tk = ws_ticks[ iTk];
-		whUseTot += tk.wtk_whUse;		// total use not including draws possibly modified by HR
-		whUseTotNoHR += tk.wtk_whUse;
 		int nD = tk.wtk_dwhrDraws.size();
+#if 0
 		if (nD == 0)
 			continue;
+#endif
 #if 0
 		if (nD > 1)
 			printf( "\nMultiple draws");
@@ -886,33 +888,30 @@ RC DHWSYS::ws_DoDWHR()
 		{	DWHRUSE& hru = tk.wtk_dwhrDraws[ iD];
 			const DHWUSE* pWU = hru.wdw_pDHWUSE;
 			fxUseMix += hru.wdw_vol;
-			float fFullTemp = hru.wdw_volHR / hru.wdw_vol;
-			if (fFullTemp < 1.f)
-				nWarmup++;
 			float fHotNoHR;
 			pWU->wu_CalcHotF( ws_tUse, ws_tInlet, fHotNoHR);
-			whUseTotNoHR += hru.wdw_vol * fHotNoHR;
+			ws_whUseNoHR += hru.wdw_vol * fHotNoHR;
 			float fWeightTot = 0.f;
 			DHWHEATREC* pWR;
 			RLUPC( WrR, pWR, pWR->ownTi == ss)
-			{	float fWeightAdj = pWR->wr_fWeight * fFullTemp;
+			{	// weight=what fraction of this DHWHEATREC contributes
+				//   wr_fWeight based on # showers etc
+				//   adjust for warmup delay via volHR/vol
+				float fWeightAdj = pWR->wr_fWeight * hru.wdw_volHR / hru.wdw_vol;
 				if (fWeightAdj < .0001f)
 					continue;	// no effect (duplicate, mult=0, ...)
-#if 0
-				if (fFullTemp > 0.f && fFullTemp < 1.f)
-					printf( "\nPartial '%s'", name);
-#endif
-				// float tHotFX = fFullTemp*ws_tUse + (1.f - fFullTemp)*ws_tInlet;
-				float tHotFX = ws_tUse;
 				float qR, qRWH;
-				float whUse = pWR->wr_CalcTick( hru.wdw_vol, pWU->wu_temp, tHotFX, ws_tInlet,
+				float whUse = pWR->wr_CalcTick( hru.wdw_vol, pWU->wu_temp, ws_tUse, ws_tInlet,
 								tk.wtk_whUse, qR, qRWH);
+#if 0
+				if (pWR->wr_eff < 0.65f)
+					printf( "\nEff = %0.3f", pWR->wr_eff);
+#endif
 				fWeightTot += fWeightAdj;
 				whUseWt += whUse * fWeightAdj;
 				qRWt   += qR   * fWeightAdj;
 				qRWHWt += qRWH * fWeightAdj;
-				tHotFXAvg += whUse * tHotFX * fWeightAdj;
-			}
+			}	// end heat recovery loop
 			if (fWeightTot < .9999f)
 				whUseWt += (1.f - fWeightTot) * hru.wdw_vol * fHotNoHR;		// not right for partial?
 		}	// end draw loop
@@ -921,32 +920,31 @@ RC DHWSYS::ws_DoDWHR()
 		float tO = ws_tInlet;
 		if (tk.wtk_whUse > 0.)
 			tO += qRWHWt / (waterRhoCp * tk.wtk_whUse);
-		else
-			printf( "\nwkt_whUse = 0");
+		else if (qRWHWt > 0.f)
+			printf("\nWhat?");
+
 		tk.wtk_tInletX = ws_AdjustTInletForSSF( tO);
-		whUseTot += whUseWt;	// hour total hot water at heater
 		qRWHSum += qRWHWt;
 		ws_qDWHR += qRWt;		// accum to hour total heat recovered
 	}  // end tick
 
+#if 0 && defined( _DEBUG)
+	if (frDiff( float( whUseTot), ws_whUse.total, .001f) > .001f)
+		printf( "\nMismatch!");
+#endif
+
 	// calc hour average adjusted inlet and hot water temps
 	float tInletXNoSSF = ws_tInlet;
 	if (qRWHSum > 0.)
-	{	tInletXNoSSF = ws_tInlet + qRWHSum / (waterRhoCp * whUseTot);
+	{	tInletXNoSSF = ws_tInlet + qRWHSum / (waterRhoCp * ws_whUse.total);
 		ws_tInletX = ws_AdjustTInletForSSF( tInletXNoSSF);
 	}
-	tHotFXAvg /= whUseTot;
 
 #if defined( _DEBUG)
-	float qXNoHR = whUseTotNoHR * waterRhoCp * (ws_tUse - ws_tInlet);
-	float qX =     whUseTot     * waterRhoCp * (ws_tUse - tInletXNoSSF);
-	float qXR = qXNoHR - qX;
-	if (frDiff(ws_qDWHR, qXR, .01f) > .001f)
-		printf( "\nDHWSYS '%s': ws_DoDHWR balance error (nWarmup=%d)", name, nWarmup);
-#if 0
-	else if (nWarmup > 0)
-		printf( "\nDHWSYS '%s': ws_DHWR nWarmup=%d", name, nWarmup);
-#endif
+	float qXNoHR = ws_whUseNoHR   * waterRhoCp * (ws_tUse - ws_tInlet);
+	float qX =     ws_whUse.total * waterRhoCp * (ws_tUse - tInletXNoSSF);
+	if (frDiff(qX+ws_qDWHR, qXNoHR, 1.f) > .001f)
+		printf( "\nDHWSYS '%s': ws_DoDHWR balance error", name);
 #endif
 
 	return rc;
@@ -2374,7 +2372,9 @@ int DHWHEATREC::wr_IsEquiv(
 			  && wr_fxServed == wr_fxServed
 		      && wr_hwEndUse == wr.wr_hwEndUse	// future proof
 			  && !ISNANDLE( wr_effRated) && !ISNANDLE( wr.wr_effRated)
-			  && wr_effRated == wr.wr_effRated;
+			  && wr_effRated == wr.wr_effRated
+			  && !ISNANDLE( wr_dTDrain) && !ISNANDLE( wr.wr_dTDrain)
+			  && wr_dTDrain == wr.wr_dTDrain;
 
 	return bEquiv;
 }		// DHWHEATREC::wr_IsEquiv
@@ -2392,16 +2392,10 @@ float DHWHEATREC::wr_CalcTick(		// calculate water quantities for tick
 // returns hot water use at WH, gal
 
 {
-#if 0
-	float vd = DWHRUse.wdw_volHR;	// useful drain vol = fixture hot vol, gal
-
-	const DHWUSE* pWU = DWHRUse.wdw_pDHWUSE;
-	float td = pWU->wu_temp;	// drain temp = fixture mix temp
-#endif
-
 	float vp, whUse, tpO;
 
-	float td = min( tUseFX, tHotFX);	// drain water temp
+	// drain water temp
+	float td = max( tpI, min( tUseFX, tHotFX) - wr_dTDrain);
 
 	if (wr_FeedsFX())
 	{	// HX feeds fixture and possibly WH