100 PRINT CHR$(26) 
110 PRINT TAB(20);"*******************************"
120 PRINT TAB(20);"*                             *"
130 PRINT TAB(20);"*  THERMODYNAMIC PROPERTIES   *"
140 PRINT TAB(20);"*          OF STEAM           *"
150 PRINT TAB(20);"*                             *"
160 PRINT TAB(20);"*     By David B. Fisher      *"
170 PRINT TAB(20);"*                             *"
180 PRINT TAB(20);"*******************************"
190 PRINT
200 PRINT TAB(20);"Microcomputer Software Project"
210 PRINT TAB(22);"Center for Energy Studies"
220 PRINT TAB(20);"University of Texas at Austin"
230 PRINT : PRINT TAB(15);"Dr. Philip S. Schmidt - Project Director"
240 PRINT 
250 PRINT "This program calculates various thermodynamic properties, such as enthalpy,"
260 PRINT "entropy, and temperature, of steam and water. You may select among 19
270 PRINT "different functions depending upon the input data you have. The program"
280 PRINT "will calculate only one value at a time and does not produce a table of"
290 PRINT "values."
300 PRINT TAB(28);"Copyright 1981"
310 FOR I = 1 TO 800 : NEXT I
320 GOSUB 360
330 XX = 0 : YY = 0 : ZZ = 0
340 ON A GOSUB 620,820,930,1060,1200,1300,1570,2070,2200,2300,2420,2620,2760,3010,3140,3440,3540,3670,3880
350 GOTO 320
360 PRINT CHR$(26)
370 PRINT TAB(28);"THERMODYNAMIC FUNCTIONS"
380 PRINT TAB(20);"======================================="
390 PRINT "1.  Enthalpy of subcooled water given temperature and pressure."
400 PRINT "2.  Enthalpy of saturated water given temperature."
410 PRINT "3.  Enthalpy of saturated water given pressure."
420 PRINT "4.  Enthalpy of saturated steam given temperature."
430 PRINT "5.  Enthalpy of saturated steam given pressure."
440 PRINT "6.  Enthalpy of superheated steam given temperature and pressure."
450 PRINT "7.  Enthalpy of superheated steam given pressure and entropy."
460 PRINT "8.  Saturation pressure given temperature."
470 PRINT "9.  Entropy of saturated water given temperature."
480 PRINT "10. Entropy of saturated water given pressure."
490 PRINT "11. Entropy of saturated steam given temperature."
500 PRINT "12. Entropy of saturated steam given pressure."
510 PRINT "13. Entropy of superheated steam given temperature and pressure."
520 PRINT "14. Saturation temperature given pressure."
530 PRINT "15. Temperature of superheated steam given enthalpy and pressure."
540 PRINT "16. Specific volume of saturated water given temperature."
550 PRINT "17. Specific volume of saturated water given pressure."
560 PRINT "18. Specific volume of superheated steam given temperature and pressure."
570 PRINT "19. Temperature of compressed liquid given pressure and enthalpy."
580 PRINT
590 INPUT "Pick one of the above functions . . .",A
600 PRINT CHR$(26)
610 RETURN
620 PRINT "Enthalpy of subcooled water as a function of temperature and pressure."
630 PRINT : PRINT
640 INPUT "Input the temperature (F)  = ",T1
650 PRINT 
660 INPUT "Input the pressure (PSIA)  = ",P
670 T = T1
680 IF ZZ = 1 THEN T = T1 - 459.69
690 T3 = T ^ 3
700 T4 = T * T3
710 A0 = .75623 + (-.01446 + 9.85037E-05 *T) * T + (-2.8685E-07 +2.87767E-10 * T) * T3
720 A1 = 3.14899E-03 + (-4.867E-06 - 2.1607E-09 * T) * T + (4.07626E-11 - 9.30412E-14 * T) * T3
730 A2 = -3.1788E-08 + (2.80539E-11 + 1.75513E-12 * T) * T + (-7.4798E-15 + 9.90718E-18 * T) * T3
740 HF = -32.46 + (1.02493 + (-4.1498E-04 + 3.07768E-06 * T) * T) * T + (-1.2602E-08 + (3.06581E-11 - 3.834E-14 * T) * T) * T4 + 1.9907E-17 * T3 * T4
750 HCL = A0 + (A1 + A2 * P) * P + HF
760 IF ZZ = 1 THEN RETURN
770 PRINT 
780 PRINT "Enthalpy  (btu/lb)         =";HCL
790 PRINT : PRINT : PRINT
800 INPUT "Press the <RETURN> key to continue.",DUMMY
810 RETURN
820 PRINT "Enthalpy of saturated water as a function of temperature."
830 PRINT 
840 INPUT "Input the temperature (F) = ",T1
850 T = T1
860 T4 = T ^ 4
870 HFT = -32.4599 + (1.02493 + (-4.1498E-04 + 3.0777E-06 * T) * T) * T + (-1.2603E-08 + (3.06581E-11 - 3.8341E-14 * T) * T) * T4 + 1.9907E-17 * T * T * T * T4
880 PRINT : PRINT
890 PRINT "Enthalpy (btu/lb)          =";HFT
900 PRINT : PRINT : PRINT
910 INPUT "Press the <RETURN> key to continue.",DUMMY
920 RETURN
930 PRINT "Enthalpy of saturated water as a function of pressure."
940 PRINT
950 INPUT "Input pressure (psia)      = ",P
960 X = .434294 * LOG(P)
970 X4 = X ^ 4
980 T = 101.74419# + (77.052576# + (11.951549# + 2.05621 * X) * X) * X + (.420705 + (-.0684109 + .0625368 * X) * X) * X4 - 6.59481E-03 * X * X * X * X4
990 T4 = T ^ 4
1000 HFP = -32.4599 + (1.02494 + (-4.14977E-04 + 3.0777E-06 * T)* T)* T + (-1.26029E-08 + (3.0658E-11 - 3.8341E-14 * T) * T)* T4 + 1.99068E-17 * T * T * T * T4
1010 PRINT
1020 PRINT "Enthalpy (btu/lb)          =";HFP
1030 PRINT : PRINT : PRINT
1040 INPUT "Press the <RETURN> key to continue.",DUMMY
1050 RETURN
1060 PRINT "Enthalpy of saturated steam as a function of temperature."
1070 PRINT
1080 INPUT "Input temperature (F)      = ",T1
1090 T = T1
1100 TK = (T - 32) / 1.8 + 273.16
1110 X = 647.27 - TK
1120 Y = X * (3.2438 + (.0058683 + 1.17024E-08 * X * X) * X) / (TK * (1+ 2.18785E-03 *X))
1130 P = 14.696 * 218.167 / (10 ^ Y)
1140 X = LOG(P) / LOG(10)
1150 HGT = 1105.9387# + (32.7568 + (4.61985 + (.20673 + (-.541169 + (.492414 - .178849 * X) * X) * X) * X) * X) * X
1160 PRINT "Enthalpy (btu/lb)          =";HGT
1170 PRINT : PRINT : PRINT
1180 INPUT "Press the <RETURN> key to continue.",DUMMY
1190 RETURN
1200 PRINT "Enthalpy of saturated steam as a function of pressure."
1210 PRINT : PRINT
1220 INPUT "Input pressure (psia)      = ",P
1230 X = LOG(P) / LOG(10)
1240 HGP = 1105.94 + (32.7568 + (4.61985 + (.20673 + (-.641169 + (.492414 - .178849 * X) * X) * X) * X) * X) * X
1250 PRINT
1260 PRINT "Enthalpy (btu/lb)          =";HGP
1270 PRINT : PRINT : PRINT
1280 INPUT "Press the <RETURN> key to continue.",DUMMY
1290 RETURN
1300 PRINT "Enthalpy of superheated steam as a function of temperature and pressure."
1310 PRINT : PRINT
1320 INPUT "Input temperature (F)      = ",T1
1330 PRINT
1340 INPUT "Input pressure (psia)      = ",P1
1350 T = 255.38 + T1 / 1.8
1360 IF XX = 1 THEN T = 255.38 + (T1 - 459.69) / 1.8
1370 P = P1 / 14.6959
1380 B1 = (2641.62 * 10 ^ (80870! / (T * T))) / T
1390 B0 = 1.89 - B1
1400 B2 = 82.546
1410 B3 = 162460! / T
1420 B4 = .21828 * T
1430 B5 = 126970! / T
1440 F0 = 1.89 - B1 * (372420! / (T * T) + 2)
1450 B6 = B0 * B3 - 2 * F0 * (B2 - B3)
1460 B7 = 2 * F0 * (B4 - B5) - B0 * B5
1470 B8 = .434294 * LOG(T)
1480 F = 775.596 + (.63296 + .0001624 * T) * T + 47.3635 * B8
1490 B9 = B0 * P * P / (2 * T * T)
1500 HTP = F + .043577 * (F0 * P + B9 * (B0 * (B2 - B3 + 2 * B7 * B9) - B6))
1510 IF XX = 1 THEN RETURN
1520 PRINT
1530 PRINT "Enthalpy (btu/lb)          =";HTP
1540 PRINT : PRINT : PRINT
1550 INPUT "Press the <RETURN> key to continue.",DUMMY
1560 RETURN
1570 PRINT "Enthalpy of wet or superheated steam as a function of pressure and entropy."
1580 PRINT : PRINT
1590 INPUT "Input pressure (psia)      = ",P
1600 PRINT
1610 INPUT "Input entropy (btu/lb-r)   = ",S
1620 IF P - 100 < 0 THEN GOTO 1650
1630 IF P - 2000 < 0 THEN GOTO 1660
1640 SG = 5.66316 / (P ^ .194936) : GOTO 1670
1650 SG = 1.98473 / (P ^ .0458907) : GOTO 1670
1660 SG = 2.2411 / (P ^ .070069)
1670 IF SG - S < 0 THEN GOTO 1690
1680 GOTO 1980
1690 X = .434294 * LOG(P)
1700 X4 = X ^ 4
1710 IF P - 10 < 0 THEN GOTO 1740
1720 IF P - 450 < 0 THEN GOTO 1810
1730 GOTO 1890
1740 S0 = 2.1501 + (-.254384 + (2.17448E-04 - 9.3986E-04 * X) * X) * X
1750 A0 = 1223.29 + (-.577813 + (.230314 - 1.04343 * X) * X) * X
1760 A1 = 820.096 + (-1.96342 + (2.60695 - .768471 * X) * X) * X
1770 A2 = 895.121 + (-10.4682 + (7.08584 - 10.321 * X) * X) * X
1780 A3 = 547.703 + (195.111 + (-313.488 + 166.948 * X) * X) * X
1790 A4 = 0
1800 GOTO 1950
1810 S0 = 2.33356 + (-.320116 + (.0869149 - .0566468 * X) * X) * X
1820 S0 = S0 + (.0183387 - .0024477 * X) * X4
1830 A0 = 1357.23 + (73.7911 + (-75.9247 + 34.2757 * X) * X) * X - 6.02702 * X4
1840 A1 = 1144.62 + (33.2973 + (-26.4518 + 8.95797 * X) * X) * X - 1.0968 * X4
1850 A2 = 993.784 + (521.133 + (-506.58 + 220.417 * X) * X) * X - 37.9825 * X4
1860 A3 = 1424.09 + (-1663.6 + (1345.66 - 489.183 * X) * X) * X + 73.0757 * X4
1870 A4 = 3431.79 + (-7341.26 + (5997.11 - 2208.42 * X) * X) * X + 297.746 * X4
1880 GOTO 1950
1890 S0 = 1.70668 + (.544009 + (-.377805 + .0770932 * X) * X) * X - .0054871 * X4
1900 A0 = 1400
1910 A1 = 742.243 + (661.035 + (-321.279 + 53.4569 * X) * X) * X
1920 A2 = -3491.44 + (4615.43 + (-1470.65 + 145.947 * X) * X) * X
1930 A3 = 34807.7 + (-35596.6 + (12288.4 - 1388.08 * X) * X) * X
1940 A4 = 0
1950 A5 = S - S0
1960 HPS = A0 + (A1 + (A2 + (A3 + A4 * A5) * A5) * A5) * A5
1970 PRINT : PRINT "Enthalpy (btu/lb)          =";HPS
1980 X = .434294 * LOG(P)
1990 X4 = X ^ 4
2000 A0 = -4.71691 + (-10.0491 + (-7.05328 - 1.94738 * X) * X) * X + (.117549 - .254735 * X) * X4
2010 A1 = 561.462 + (76.9333 + (12.1177 + 2.12914 * X) * X) * X + (.128501 + .144378 * X) * X4
2020 HPS = A0 + A1 * S
2030 PRINT : PRINT "Enthalpy (btu/lb)           =";HPS
2040 PRINT : PRINT : PRINT
2050 INPUT "Press the <RETURN> key to continue.",DUMMY
2060 RETURN
2070 PRINT "Saturation pressure as a function of temperature."
2080 PRINT : PRINT
2090 INPUT "Input temperature (F)      = ",T1
2100 T = T1
2110 TK = (T - 32) / 1.8 + 273.16
2120 X = 647.27 - TK
2130 Y = X * (3.2438 + (.0058683 + 1.17024E-08 * X * X) * X) / (TK * (1 + 2.18785E-03 * X))
2140 PSL = 14.696 * 218.167 / (10 ^ Y)
2150 PRINT 
2160 PRINT "Saturation pressure (psia) =";PSL
2170 PRINT : PRINT : PRINT
2180 INPUT "Press the <RETURN> key to continue.",DUMMY
2190 RETURN
2200 PRINT "Entropy of saturated water as a function of temperature."
2210 PRINT : PRINT
2220 INPUT "Input temperature (F)      = ",T1
2230 T = T1
2240 TB = (T - 360) / 3100
2250 SFT = .515775 + (3.96796 - (4.59799 - (34.2517 - (60.7233 + (367.036 - (12035.9 + 123466! * TB) * TB) * TB) * TB) * TB) * TB) * TB
2260 PRINT
2270 PRINT "Entropy (btu/lb-r)         =";SFT
2280 PRINT : PRINT : PRINT
2290 INPUT "Press the <RETURN> key to continue.",DUMMY
2295 RETURN
2300 PRINT "Entropy of saturated water as a function of pressure."
2310 PRINT : PRINT
2320 INPUT "Input pressure (psia)      = ",P
2330 YY = 1
2340 GOSUB 3040
2350 TB = (TSL - 360) / 3100
2360 SFP = .515755 + (3.96796 - (4.59799 - (34.2517 - ( 60.7233 + (367.036 - (12035.9 + 123466! * TB) * TB) * TB) * TB) * TB) * TB) * TB
2370 PRINT
2380 PRINT "Entropy (btu/lb-r)         =";SFP
2390 PRINT : PRINT : PRINT
2400 INPUT "Press the <RETURN> key to continue.",DUMMY
2410 RETURN
2420 PRINT "Entropy of saturated steam as a function of temperature."
2430 PRINT : PRINT
2440 INPUT "Input temperature (F)      = ",T1
2450 T = T1
2460 TK = (T - 32) / 1.8 + 273.16
2470 X = 647.27 - TK
2480 Y = X * (3.2438 + (.0058683 + 1.17024E-08 * X * X) * X) / (TK * (1 + 2.18785E-03 * X))
2490 P = 14.696 * 218.167 / (10 ^ Y)
2500 IF P - 100 < 0 THEN GOTO 2520
2510 GOTO 2540
2520 SGT = 1.98473 / (P ^ .0458907)
2530 GOTO 2570
2540 IF P - 2000 < = 0 THEN GOTO 2560
2550 SGT = 5.66316 / (P ^ .194936) : GOTO 2570
2560 SGT = 2.2411 / (P ^ .070069)
2570 PRINT
2580 PRINT "Entropy (btu/lb-r)         =";SGT
2590 PRINT : PRINT : PRINT 
2600 INPUT "Press the <RETURN> key to continue.",DUMMY
2610 RETURN
2620 PRINT "Entropy of saturated steam as a function of pressure."
2630 PRINT : PRINT
2640 INPUT "Input pressure (psia)      = ",P
2650 IF P - 100 < = 0 THEN GOTO 2680
2660 IF P - 2000 < = 0 THEN GOTO 2700
2670 SGP = 5.66316 / (P ^ .19494) : GOTO 2710
2680 SGP = 1.98473 / (P ^ .04589)
2690 GOTO 2710
2700 SGP = 2.2411 / (P ^ .07007)
2710 PRINT
2720 PRINT "Entropy (btu/lb-r)         =";SGP
2730 PRINT : PRINT : PRINT
2740 INPUT "Press the <RETURN> key to continue.",DUMMY
2750 RETURN
2760 PRINT "Entropy of superheated steam as a function of temperature and pressure."
2770 PRINT : PRINT
2780 INPUT "Input temperature (F)      = ",T1
2790 PRINT
2800 INPUT "Input pressure (psia)      = ",P1
2810 T = 255.38 + T1 / 1.8
2820 P = P1 / 14.696
2830 B1 = (2641.62 * 10 ^ (80870! / (T * T))) / T
2840 B0 = 1.89 - B1
2850 B2 = 82.546
2860 B3 = 162460!
2870 B4 = .21828 * T
2880 B5 = 126970! / T
2890 F0 = 1.89 - B1 * (372420! / (T * T) + 2)
2900 B6 = B0 * B3 - 2 * F0 * (B2 - B3)
2910 B7 = 2 * F0 * (B4 - B5) - B0 * B5
2920 B8 = .43429448# * LOG(T)
2930 B9 = B0 * P * P / (2 * T * T)
2940 BETA = ((B0 - F0) * P + B9 * (B6 + B9 * B0 * (B0 * (B4 - B5) - 2 * B7))) / T
2950 STP = .809691 * B8 - .253801 * .434294 * LOG(P) + .0001805 * T - 11.4267 / T - .355579 - .0241983 * BETA
2960 PRINT
2970 PRINT "Entropy (btu/lb-r)         =";STP
2980 PRINT : PRINT : PRINT
2990 INPUT "Press the <RETURN> key to continue.",DUMMY
3000 RETURN
3010 PRINT "Saturation temperature as a function of pressure."
3020 PRINT : PRINT
3030 INPUT "Input pressure (psia)      = ",P
3040 X = .434294 * LOG(P)
3050 X4 = X ^ 4
3060 TSL = 101.744 + (77.0526 + (11.9515 + 2.05621 * X) * X) * X + (.420705 + (-.0684109 + .0625368 * X) * X) * X4 - .0065948 * X * X * X * X4
3070 IF ZZ = 1 THEN RETURN
3080 IF YY = 1 THEN RETURN
3090 PRINT
3100 PRINT "Saturation temperature (F)  =";TSL
3110 PRINT : PRINT : PRINT
3120 INPUT "Press the <RETURN> key to continue.",DUMMY
3130 RETURN
3140 PRINT "Temperature of superheated steam as a function of enthalpy and pressure."
3150 PRINT : PRINT
3160 INPUT "Input enthalpy (btu/lb)    = ",H
3170 PRINT
3180 INPUT "Input pressure (psia)      = ",P1
3190 ESP = .01
3200 DT = 2
3210 X = 1.68 * H - 1110
3220 T1 = X
3230 XX = 1
3240 GOSUB 1350
3250 H1 = HTP
3260 FOR I = 1 TO 10
3270 TDT = X + DT
3280 T1 = TDT
3290 GOSUB 1350
3300 X = X + DT * (H - H1) / (HTP - H1)
3310 T1 = X
3320 GOSUB 1350
3330 H1 = HTP
3340 IF ABS(H - H1) - EPS < = 0 THEN 3380
3350 NEXT I
3360 PRINT
3370 PRINT "      This function does not converge."
3380 THP = X - 459.69
3390 PRINT
3400 PRINT "Temperature (F)            =";THP
3410 PRINT : PRINT : PRINT
3420 INPUT "Press the <RETURN> key to continue.",DUMMY
3430 RETURN
3440 PRINT "Specific volume of saturated water as a function of temperature."
3450 PRINT : PRINT
3460 INPUT "Input temperature (F)      = ",T
3470 T1 = T / 1000
3480 VFT = (1.58529 + (.260305 + (-.726856 + (10.972689# + (-25.343 + 23.0713 * T1) * T1) * T1) * T1) * T1) / 100
3490 PRINT
3500 PRINT "Specific volume (cf/lb)    =";VFT
3510 PRINT : PRINT : PRINT
3520 INPUT "Press the <RETURN> key to continue.",DUMMY
3530 RETURN
3540 PRINT "Specific volume of saturated water as a function of pressure."
3550 PRINT : PRINT
3560 INPUT "Input pressure (psia)      = ",P
3570 X = .434294 * LOG(P)
3580 X4 = X ^ 4
3590 T = 101.744 + (77.0526 + (11.9515 + 2.0562 * X) * X) * X + (.420705 + (-.0684109 + .0625368 * X) * X) * X4 - .0065948 * X * X * X * X4
3600 T1 = T / 1000
3610 VFP = (1.58529 + (.260305 + (-.723856 + (10.9727 + (-25.343 + 23.0713 * T1) * T1) * T1) * T1) * T1) / 100
3620 PRINT
3630 PRINT "Specific volume (cf/lb)    =";VFP
3640 PRINT : PRINT : PRINT
3650 INPUT "Press the <RETURN> key to continue.",DUMMY
3660 RETURN
3670 PRINT "Specific volume of superheated steam as a function of temperature and pressure."
3680 PRINT : PRINT 
3690 INPUT "Input temperature (F)      = ",T1
3700 PRINT
3710 INPUT "Input pressure (psia)      = ",P1
3720 T = 255.38 + T1 / 1.8
3730 P = P1 / 14.696
3740 B1 = (2641.62 * 10 ^ (80870! / (T * T))) / T
3750 B0 = 1.89 - B1
3760 B2 = 82.546
3770 B3 = 162460! / T
3780 B4 = .21828 * T
3790 B5 = 126970! / T
3800 Z = B0 * P / (T * T)
3810 B = B0 * (1 + Z * (B2 - B3 + Z * (B4 - B5) * B0 * P))
3820 VTP = .0160185 * (4.55504 * T / P + B)
3830 PRINT
3840 PRINT "Specific volume (cf/lb)    =";VTP
3850 PRINT : PRINT : PRINT
3860 INPUT "Press the <RETURN> key to continue.",DUMMY
3870 RETURN
3880 PRINT "Temperature of compressed liquid as a function of pressure and enthalpy."
3890 PRINT : PRINT
3900 INPUT "Input pressure (psia)      = ",P
3910 PRINT
3920 INPUT "Input enthalpy (btu/lb)    = ",H
3930 ZZ = 1
3940 GOSUB 3040
3950 TH = TSL + 459.69
3960 TL = 480
3970 FOR I = 1 TO 100
3980 T1 = (TH + TL) / 2
3990 GOSUB 670
4000 H2 = HCL
4010 IF ABS(H - H2) < .01 THEN GOTO 4070
4020 IF H - H2 < 0 THEN GOTO 4040
4030 TL = T1 : GOTO 4050
4040 TH = T1
4050 NEXT I
4060 PRINT : PRINT "      This function does not converge."
4070 TCL = T1 
4080 PRINT
4090 PRINT "Temperature (F)            =";TCL - 459.69
4100 PRINT : PRINT : PRINT
4110 INPUT "Press the <RETURN> key to continue.",DUMMY
4120 RETURN
)            =";TCL - 459.69
4100 PRINT : PRINT