ENGINEERING RESEARCH INSTITUTE THE UNIVERSITY OF MICHIGAN ANN ARBOR CONDENSATION OF FREON-12 IN 11-FINS-PERINCH AND 19-FINS-PER-INCH COAXIAL COILS Report No. 46 Edwin H. Young of Chemical and Metallurgical Engineering Associate Professor Jack A. Alcalay James R. Wall Robert H. Cherry Marvin L. Katz Robert W. Gutchess Larry D. Wheaton Research Assistants Project 1592 CALUMET AND HECLA, INCORPORATED WOLVERINE TUBE DIVISION DETROIT, MICHIGAN February 1957

The University of Michigan T Engineering Research Institute TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES OBJECTIVE ABSTRACT I. SCOPE OF INVESTIGATION II. DESCRIPTION OF COIIS III. DESCRIPTION OF APPARATUS A. Freon Circuit B. Auxiliary Circuits 1. Evaporator 1 2. Condenser C, 5. Freon Desupi Page iii iii vi vi 1 2 2 2 4 4 4 4 5 Water Circuit ooling Water Circuit erheating Circuit IV. PROCEDURE V. RESULTS AND DISCUSSION OF RESULTS ii

The University of Michigan T Engineering Research Institute LIST OF TABLES Table Page I Description of Coaxial Coils 9 II Summary of Test Data 10 III Condensing Water Pressure Drop Data 16 LIST OF FIGURES Figure Page 1 44'-7" long 19-fin-per-inch coaxial coil 19 2 5'l-111" long 19-fin-per-inch coaxial coil 19 3 ll1'-lO0l" long 19-fin-per-inch coaxial coil 20 4 31'-6"tt long 11-fin-per-inch coaxial coil 20 5 6'-0" long ll-fin-per-inch coaxial coil 21 6 12'-8" long lf-fin-per-inch coaxial coil 21 7 Cross-sectional view of the 11-fin-per-inch coil 22 8 Cross-sectional view of the 19-fin-per-inch coil 22 9 Compressor and condensing section 22 10 Freon-12 evaporator and evaporator water system 23 11 View of the liquid seal and the desuperheater 23 12 Freon circuit 24 13 Heat transfer performance of coil No. 79 (11 fins/ inch - 3'-6~" long) 25 14 Heat transfer performance of coil No. 73 (19 fins/ inch - 41-7" long) 26 iii

The University of Michigan Engineering Research Institute LIST OF FIGURES (Cont.) Figure 15 Heat inch 16 Heat inch 17 Heat inch 18 Heat inch 19 Heat 20 Heat 21 Heat 22 Heat 23 Heat Page transfer performance - 6'-O long) transfer performance - 5t-ll1" long) transfer performance - 12'-8" long) transfer performance - 11'-10" long) transfer performance transfer performance transfer performance transfer performance transfer performance transfer performance of coil No. 78 (11 fins/ of coil No. 74 (19 fins/ of coil No. 77 (11 fins/ of coil No. 75 (19 fins/ cross-plot for coil No. cross-plot for coil No. cross-plot for coil No. cross-plot for coil No. cross-plot for coil No. cross-plot for coil No. four-foot coils six-foot coils twelve-foot coils 79 73 78 74 77 75 27 28 29 50 31 32 33 34 35 56 37 38 39 24 Heat transfer performance 25 Summary of performance of 26 Summary of performance of 27 Summary of performance of 28 Effect of length of coil on heat load with a constant water flow rate of 50 lbs. per minute 29 Effect of length of coil on heat load with a constant water flow rate of 100 lbs. per minute 50 Effect of length of coil on heat load with a constant water flow rate of 150 lbs. per minute 31 Summary of pressure drop data for the four-foot coils 52 Summary of pressure drop data for the six-foot coils 41 42 43 4 iv

The University of Michigan T Engineering Research Institute Figure 33 34 35 36 37 3839 LIST OF FIGURES (Concl.) Summary of pressure drop coils Water side pressure drop inch - 3'-6-1/2" long) Water side pressure drop inch - 47-7" long) Water side pressure drop inch - 6'-0" long) Water side pressure drop inch - 5'-11-1/2" long) Water side pressure drop inch - 12'-8" long) Water side pressure drop inch - 11'-10-1/2" long) data for for coil for coil for coil for coil for coil for coil the No. No. No. No. No. No. twelve-foot 79 (11 fins/ 73 (19 fins/ 78 (11 fins/ 74 (19 fins/ 77 (11 fins/ 75 (19 fins/ Page 45 46 47 48 49 50 51 v

I The University of Michigan Engineering Research Institute OBJECTIVE The objective of this investigation was to determine the relative performance of a series of six coaxial finned tube coils with Freon12 condensing in the annulus of the coils. ASTRACT The relative performance of three ll-fin-per-inch coaxial coils of various lengths and three 19-fin-per-inch coils of various lengths were individually determined in a five ton refrigeration system charged with Freon-12. Heat transfer and pressure performance curves are presented for 85, 115, and 135 psig. condensing pressures as a function of various condensing water flow rates. vi

The University of Michigan T Engineering Research Institute I. SCOPE OF INVESTIGATION The object of this investigation was to determine the relative performance of various finned tube coaxial coils when condensing Freon12 in a five ton refrigeration application. The geometrical and physical features of these coils are described in Section II of this report. The following aspects of comparison were considered: 1. Rates of heat removal with Freon-12 condensing in the annulus of the coils with variation in: a. cooling water flow rate, b. Freon-12 condensing pressures, and c. length of coil. 2. Pressure drop on freon side, and 3. Pressure drop on water side. The experimentation was conducted in the condensing section of a five ton refrigeration system. Saturated or slightly superheated Freon-12 vapor was fed to the annulus of the coil where it was condensed on the finned side of the inner tube by means of water flowing inside the inner tube. Many other factors which play an important role in the performance of the coils were not studied in this investigation. These are; 1. Outside shape of the coil (i.e., helical, spiral, slope per foot of length), and 2. Annulus cross sectional area, internal tube geometry, and external tube geometry. A quantitative consideration of these factors was beyond the scope of the present study, since it would require a great number of different coils and more elaborate experimental equipment. i 1

The University of Michigan * Engineering Research Institute II. DESCRIPTION OF COIIS Coaxial coils fabricated with 11-fin-per-inch tubes and 19-finper-inch tubes inside of 18 gage 1-1/8 inch bare copper tube approximately twenty-five feet long were originally provided by Wolverine Tube. Preliminary studies indicated that the coils would have to be shortened in order to undertake the investigation. The coils were returned to Wolverine Tube for modification. Subsequently coils approximately 4 feet, 6 feet, and 12 feet long were received for investigation. Table I presents detailed information concerning the coils tested. Figures 1, 2, and 5 show the 4 ft.-7 inch 5 ft,-11- inch, and 11 ft.-lO- inch long 19wfin-per-inch coils. Figures 4, 5, and show the 3 ft. -6-i inch, 6 ft.-O inch, and 12 ft.-8 inch long 11-fin-per-inch coils studied in this investigation. Figures 7 and 8 show cross sections of the 11-fin-per-inch and 19-fin-per-inch coils. III. DESCRIPTION OF APPARATUS The equipment used in this investigation was originally fabricated by D. R. Robinson as a Trufin Fellow for his doctoral dissertation in finned tube heat transfer in 1949. The same equipment was later used by J. E. Myers in his doctoral dissertation research also as a Trufin Fellow. This apparatus, consisting essentially of a five ton compressor, a condenser, and an evaporator together with considerable auxiliary equipment, had to be modified in many ways to fit the investigation of the performance of the coaxial coils. In essence the coils studied replaced the original condenser used by Robinson and Myers. Figures 9, 10, and 11 show the equipment as modified for this investigation. Three stream circuits were necessary for the measurements of the heat loads. The first and main circuit contained and handled the Freon-12. The other two circuits consisted of the evaporator water circulation system and the desuperheating and condensing water systems. A. Freon Circuit. The Freon circuit flow sheet is shown in Figure 12. The system consisted of the following units: the evaporator, the compressor and its accessories, the vapor liquid separator, the liquid Freon seal, the finned tube coaxial coils and an auxiliary condenser. The Freon gas leaving the evaporator flowed through valve V2 (see Figure 12) to the suction side of the compressor. The inlet suction pressure was measured by gage P2. The Freon in passing through the compressor became contaminated with lubricating oil. The compressed gas was therefore passed through an oil separator. The oil separator was an Aminco Refrigeration Products Company type 820 F separator. - 2

The University of Michigan * Engineering Research Institute The compressed Freon gas after passing through the oil separator could be admitted through valve V3 to the coaxial coil condensing system or through valve V4 to the auxiliary condenser. The auxiliary condenser was seldom used. The vapor was desuperheated in a concentric pipe heat exchanger to a predetermined level. All of the runs at a given inlet coil pressure were conducted at a constant inlet Freon temperature. At the inlet and outlet of the coil the temperature and pressure T1, P4 and T2, P5 were measured. The condensed Freon then passed to a liquid seal unit. This liquid seal was fabricated from a piece of 4 in. pipe about 14 in. long. It was fitted with a vent valve through which noncondensibles could be bled and a sight glass tube was provided along the side of the unit. The condensate then returned through a vapor liquid separator back to the evaporator. The compressor used was a five ton carrier type 5F-50 model, operating three cylinders at 1750 rpm from a 5 hp drive. The unit was equipped with an automatic low and high pressure shut off switch, and an automatic oil safety switch which shut off the- compressor whenever the difference- between the oil pressure and suction pressure became less than about 45 psig. The evaporator had a rectangular cross sectional shape. It measured 17-3/8 in. high by 7-14 in. wide by 39 in. long inside and was fabricated of 1/2 in. steel plate. It was fitted with a safety valve set to relieve at 150 psig, a pressure gage P1, and three bullts eye sight glasses welded into the sides at three different levels. These windows were used to observe the Freon liquid level. A tube bundle of 16 gage 3/4 in. copper tubes was used in the evaporator. Through these tubes water was circulated to provide the necessary latent heat of evaporation and keep the evaporator pressure at a predetermined level. The auxiliary condenser was a water cooled multipass unit containing finned tubes. Figure 9 shows the following units: A. Coaxial Coil Bo Five Ton Compressor C. Auxiliary Condenser D. Vapor-Liquid Separation Figure 10 shows the following units: E. The Evaporator F. Hot Water Surge Tank G. Evaporator Water Recirculation Pump H. Evaporator Tube Bank Exit Section M. Evaporator Water Preheater J1

I The University of Michigan T Engineering Research Institute 1 Figure 11 shows the following units: I. Liquid Seal Unit J. Condensing Water Pre-Heater K. Oil Separator L. Freon Vapor Desuperheater B. Auxiliary Circuits 1. Evaporator Water Circuit. The evaporator water circuit is shown in Figure 10. The heat of evaporation was provided by recirculated warm water. The circuit consists of a surge tank F, a pump G. and a pre-heater M. The discharge from the pump was divided into two streams, one going to the evaporator and the other bypassed to the suction side of the pump for capacity control, The water was then returned to the surge tank. The pump took suction from the storage tank through a small stream heater. 2. Condenser Cooling Water Circuit. Cooling water for the condensing coil was admitted from the main to a vertical heat exchanger (Unit J of Fig. 11) where it was preheated by means of steam to a constant temperature of 220C. It was then admitted to the coil. Both the inlet and outlet temperatures were measured (T1 and T2 of Fig. 12). The rate of flow was determined by collecting and weighing the water in a weigh barrel for a certain period of time. 3. Freon Desuperheating Circuit. Part of the Freon line at the inlet of the coil was jacketed and cooled by water coming from the water main. The flow rate of water required for the desired desuperheating was manually controlled by means of valves. IV. PROCEDURE A typical run consisted of operating the system under predetermined conditions such that the inlet Freon to the coaxial coil was entering at either 85, 115, or 135 psig. At the same time the condensing water flow rate was set at a predetermined value, always adjusting and holding the inlet water temperature at 22~C. The Freon was partially desuperheated before entering the coaxial coil. In starting up, both water circuits where turned on and the coaxial coil inlet condensing water was adjusted to 22'C. The next step consisted of setting all valves in the Freon circuit following a sequence. The prescribed sequence prevented any liquid Freon from accumulating in the compressor crankcase and also prevented loss of oil from the crankcase into the Freon circuit. The compressor was started up and the pressure of the I

The University of Michigan Engineering Research Institute Freon at the inlet of the coil was set at the prescribed level by valve V2 of Figure 12. The pressure in the evaporator was held close to 50 psig by controlling the temperature and flow rate of the evaporator tube side water. Measurements: When the inlet water temperature to the coil read 22~C for the given water flow rate the following steps were taken, The amount of superheat of the Freon vapor was reduced to approximately 5~C by controlling the rate of water flow in the desuperheater. The water rate flowing through the coaxial coil was then measured using a weigh barrel. The inlet and outlet Freon and water temperatures and pressures were read. The pressure at the evaporator and the compressor outlet pressure were also recorded. For a given water flow rate a series of runs at different condensing Freon pressures were taken. For these runs no adjustment of the inlet water temperature was needed. It was necessary, however, to readjust the Freon inlet temperature, and the pressure at the evaporator, The condensing water flow rate was then changed and a new series of runs at different inlet Freon condensing pressures was taken, V. RESULTS AND DISCUSSION OF RESULTS The experimental method used followed closely, but not exactly for reasons mentioned below, the condenser water method described in Section 26 of the A.S.R.E. Standard Methods for Testing Mechanical Condensing Units, prepared and approved by the A.Sg.R.E. Council June 11, 1940. (AoS.RE. Standard 14-41). The following measurements were taken for each run: 1. Pressure of vapor refrigerant entering condenser coil, 2. Temperature of vapor refrigerant entering condenser coil, 3. Pressure of liquid refrigerant leaving condenser coil, 4. Temperature of liquid refrigerant leaving condenser coil, 5. Temperature of water entering condenser, 6. Temperature of water leaving condenser, 7. Weight of condenser cooling water per unit time, 8. Evaporator pressure. Three or four consecutive measurements were taken after equilibrium was reached., Not all runs are listed in this report. As indicated earlier in this report, at the beginning of the experimentation period, runs were taken 5

! The University of Michigan T Engineering Research Institute on smaple coaxial coils whose capacity exceeded the available capacity and load limit of the compressor. These coils were sent back and by request were cut to shorter lengths. Only the runs taken on these shortened coils are recorded in Table No. II. Only the arithmetic average of the four measurements of each run is recorded. The recorded pressures and temperatures include the necessary corrections determined by calibration of the thermometers and pressure gages. The formula for calculation of the capacity of a condensing unit proposed by A.S.R.E. Standard 14-41 is (h g hfi) j(l -,S[wj(t2 -t,)+... (1) (h3 hf3 where: hf heat content of refrigerant liquid leaving condensing unit, in Btu. per lb. h heat content of refrigerant liquid leaving the condenser, in Btu. per lb. h = heat content of refrigerant vapor entering condensing unit, gl under the conditions specified in the A.S.RIE. Standard Method of Rating Mechanical Condensing Units, in Btu, per lb. h = heat content of refrigerant vapor entering condenser, in Btu. per lb. Q = condensing unit capacity, in Btu. per hr. n= heat loss from condenser to surrounding air, in Btu. per hr.. S Ua(t - ta) approximately. S = outside surface of condenser, in sq. ft. Ua = air film heat transfer coefficient, in Btu, per hr. per sq. ft. per ~F. ta = ambient temperature, in ~F. tc = external surface temperature of condenser, in ~F. t c= condenser entering water temperature, in ~F. t2 = condenser leaving water temperature, in ~F W = flow of condenser cooling water, in lb. per hr. The nomenclature used above in formula (1) follows exactly that specified in A.S.R.E. Standard 14-41. This formula was not used in calculating Q. Instead the heat load handled by the coil was calculated as follows: Q = W(t2 - t1) (2) 1 6

The University of Michigan * Engineering Research Institute The reason for this is that Equation 1 applies to the testing of a complete condensing unit. The correction coefficient factor in Equation 1 takes into account the difference in enthalpy of the liquid refrigerant leaving the condenser unit and that of the liquid refrigerant leaving the condenser proper. The investigation described in this report was concerned with the performance of coaxial coils. The results should be independent of the overall setup in which the coaxial coils may be used. This correction factor was therefore not required in this investigation. It should be noted that the term Qn was also not used. This term represents the rate of heat loss to the ambient air by convection and radiation from the outside surface of the coil. It can be estimated that under the most unfavorable conditions that could be encountered in the course of the experimentation, this heat loss represented at most 5 percent of the total heat capacity Q. As explained below, other factors affect the performance to a greater degree. Figures 13 through 18 are plots of heat loads Q, in Btu per hour, versus condensing water flow rates, in pounds per hour, with Freon condensing pressure as the parameter. It should be noted that sometime during the experimentation the pressure gages measuring the inlet and outlet Freon pressures deviated from their original calibrations. The exact time at which this deviation developed could not be exactly determined. All of the coils were therefore tested again. Both the original and final data are tabulated in this report. The filled circles in the figures referred to above represent the original data while the unfilled circles represent the final data. The pressure parameters indicated on the final data curves is that measured after recalibrating the pressure gages. The old data curves are labeled with pressures obtained from the cross-plot curves, Q versus P, Figures 19 through 24, with parameters of water flow rate. This latter group of figures was prepared using only the final data. The dash lined curves on Figures 13 through 18 and 25 through 27 were obtained from reading values from the Q versus P cross plots (Fig. 19 through 24)). Figures 25 through 2-" are comparison curves for the short, medium, and long coils. The Freon pressure drop plots (Figs. 35 through 33) are also based exclusively on the final data. In the summary of results Table II the outlet Freon pressure column was left blank in the case of the original data. The inlet Freon pressure column for the old data lists the pressures read off from the 0 vs P curves by locating the measured Q and the corresponding measured flow rate curve and reading the inlet pressure on the abscissa. A separate set of isothermal runs-was taken: to'determine the pressure drop of the condenser water at different water flow rates. For low water rates the pressure drop was measured by means of a mercury manometer. For the higher water flow rates the inlet and outlet pressures were measured by means of calibrated pressure gages. Corrections were made for the static head difference. The data is tabulated in Table III. The pressure drop is plotted versus the water flow rates in Figs. 34 through 393 Three particularly interesting and indicative plots are given in Figs. 28, 29, and 30. In these figures the heat loads Q are plotted versus L 7

- The University of Michigan * Engineering Research Institute the length of the six coaxial coils at what are considered to be representative water flow rates (50, 100, and 150 lbs. per minute) with Freon condensing pressure as the parameter. Figure 25 indicates that the 19 fin-per-inch short coil is superior to the 11 fin-per-inch short coil. It should be noted, however, that the 19 fin-per-inch short coil is more than one foot longer than the 11 fin-per-inch coil. This figure must therefore be used with caution. The medium length coils are comparable in length. For high Freon condensing pressures the 11 fin-per-inch coil indicates superior performance. At high condensing water flow rates, however, the slope of the 11 fin-per-inch performance curve decreases faster than the corresponding 19 fin-per-inch curve and the curves cross. It is believed that differences in the Freon side cross sectional free flow area, geometrical deformations of the coil cross sections as a result of coiling of the tubes (Figures 7 and 8), finned tube geometry differences, and to some extent the shape of the coils all influenced the resulting performances of the coils. The precise mechanism which caused the curves to cross is unknown. Figures 28, 29, and 30 indicate that there are definite coil length limitations beyond which the added length is not effective in condensing. It should be noted that any added length results mostly in supercooling of the condensate. Figures 31, 32, and 33 indicate that there is no significant difference in the Freon pressure drops between 11 fin-per-inch and 19 fin-perinch coils of the same length. 8

TABLE I DESCRIPTION OF COAXIAL COILS Length Fins A. Coil No.TubeMate Per D DA I.D. A ft. No. of Tube Inch r ft/ft ft2/ft 75 4 ft. - 7 in. 196047-01 Copper 19 0.824 0.711 o.6l1 0.556 0.160 74 5 ft. - l- in. 196047-01 Copper 19 0.824 0.711 0.611 0.556 0.160 79 3 ft. - 6 in. 60-115052-01 Copper 11 0.904 0.679 0.598 0.762 0.1565 77 12 ft. - 8 in. 60-115032-01 Copper 11 0.904 0.679 0.598 0.762 0.1565 78 6 ft. - 0 in, 60-115032-01 Copper 11 0.904 0.679 0.598 0.762 0.1565 0 o* 0) 0 m go 3 m~ m 00 5; m~ m~ a) -I n =1 M V) 0 =r a r+ ro

i~~ TABLE II SUMMARY OF TEST DATA -I m, Q t. r+ Btu/hr. ~ Run Water Temperature No. In Out Water H20AT AT Corr. Freon Temperature In Out Freon Pressure Freon Evap. In Out AP Pres. Water Rate oc ~C ~C ~C ~C ~C Psi Psi Psi Psi # Sec. #/min. Coil No. 79, Wolverine 60-115032-01, 11 fin/inch, 3 ft. 61in. c 479 480 482 483 484 485 486 ) 141 143 145 146 148 150 151 152 153 154 155 156 157 159 160 161 162 163 22.00 21.95 21.97 21.97 22.03 22.05 22.05 22.10 22.02 22.02 21.90 22.05 22.00 21.95 21.95 21.90 21.93 21.86 21.95 22.00 21.80 21.88 21.87 21.85 22.10 23.55 22.90 23.13 23.85 25.20 24.17 25.20 24.10 22.97 25.27 23.23 22.90 23.03 22.70 22.70 23.30 23.68 24.18 25.03 26.05 23.36 22.53 22.95 22.90 22.70 1.55 0.95 1.16 1.88 3.17 2.12 3.15 2.00 0.95 3.25 1.33 0.85 1.03 0.75 0.75 1.40 1.75 2.32 3.08 4.05 1.56 0.65 1.08 1.05 0.60 1.75 1.15 1.36 2.08 3.37 2.32 3.35 2.20 1.15 3.45 1.53 1.05 1.23 0.95 0.95 1.60 1.95 2.52 3.28 4.25 1.76 o.85 1.28 1.25 0.80 58.5 59.0 51.0 56.0 60.0 48.0 54.0 58.6 54.0 46.8 49.3 46.5 50.35 53.8 53.3 56.65 55.65 53.0 57.7 54.45 53.2 39.8 40.2 39.3 41.3 38.0 33.2 31.9 37.8 40.0 35.0 41.0 30.8 31.8 32.2 31.2 31.6 32.0 33.55 34.0 39.05 39.75 39.8 40.6 41.65 39.4 25.8 26.5 26.1 25.7 134 114 115 134.5 134.5 114 136 104 104 104 104 104 104 104 104 134 128 128 128 128 128 85 85 85 85 125 111 112 125 131 111 130 84 84 84 83.5 9 3 3 9.5 3.5 3 6 1 1 1 1.5 43 51 69 62 58 47 52 50 37.5 42 36 27 22 7 1.0 5o0 42 37 34 30 39 38.5 32 34 28.5 50 16.5 50 16.5 50 20.5 50 20.5 30 23.5 30 23.0 30 23.0 20 28.6 25 11.75 20 73.2 50 35.5 50 21.6 25 13.5 25 8.8 50 17.5 50 17.9 50 21.7 30 19.5 30 29.2 25 39.7 50 20.4 50 65.2 20 44.6 15 48.8 20 27.3 182 182 146 146 76.6 78.3 78.3 42 127.5 16.38 84.5 139 111.1 170.5 171.2 167.5 138.3 92.3 61.7 37.8 154 46.1 26.9 18.45 44 34,400 22,600 21,450 32, 800 27,900 18,150 28,300 9,970 15,850 6,100 13,950 15,750 14,770 17,470 17,550 32,600 29,100 25,100 21, 850 17,400 29,300 4,230 3,720 2,490 3,800 m 3 m_ 3 -1 go ro. 3 0 VW 3' _. ao cu+ -^ I

TABLE II (Continued) Run Water Temperature Water H20AT Freon Temperature No. In Out AT Corr. In Out Freon Pressure Freon Evap. Water Rate In Out AP Pres. ~C oC oC oC oC oC Psi Psi Psi Psi # Sec. #/min. Coil No. 78, Wolverine 60-115032-01, 11 fin/inch, 6 ft. 206 22.01 207 22.00 208 22.00 209 21.98 210 22.08 211 21.90 212 21.90 213 22.08 215 22.05 216 22.03 217 22.00 218 22.10 221 22.05 222 22.00 223 21.97 224 21.95 225 22.03 226 22.02 332 21.98 333 21.99 334 21.95 335 22.00 336 22.00 337 22.05 338 22.05 339 22.00 340 22.03 341 21.99 342 22.00 343 21.95 344 22.00 345 22.05 346 22.05 347 22.00 350 22.00 351 22.00 23.32 23.70 23.25 23.43 23.63 23.65 24.40 25.28 24.95 25.63 26.55 28.40 24.70 26.30 22.51 22.50 22.33 22.75 24.33 23.39 22.30 23.90 24.85 26.00 24.50 22.40 22.93 25.59 27.50 29.70 27.00 23.20 24.60 25.90 24.55 22.50 1.31 1.48 1.70 1.87 1.25 1.42 1.45 1.62 1.55 1.72 1.75 1.92 2.50 2.67 3.20 3.37 2.90 3.07 3.60 3.77 4.55 4.72 6.30 6.47 2.65 2.82 4.30 4.47 22.54 0.72 0.55 0.72 0.30 0.47 0.73 0.90 2.35 2.50 1.40 1.70 0.35 0.55 1.90 2.10 2.85 3.05 3.95 4.15 2.45 2.75 0.40 0.60 0.90 1.10 3.60 3.75 5.50 5.70 7.75 7.95 5.00 5.20 1.15 1.35 2.55 2.75 3.90 4.10 2.55 2.75 0.50 0.70 57.6 57.4 47.85 48.75 48.75 48.25 48.0 54.8 57.35 55.4 57.0 52.75 51.30 54.4 35.3 37.4 40.1 39.1 61.7 49.4 40.3 52.6 58.6 58.0 51.4 41.5 38.5 59.2 58.5 64.0 59.8 38.7 49.9 55.8 50.6 41.5 32.2 32.5 31.65 31.9 32.0 32.0 33.0 33.4 35.3 36.2 37.55 39.35 33.3 37.2 25.6 25.7 25.4 24.9 35.0 32.3 25.0 33.2 35.7 27.3 33.7 26.6 26.7 35.2 39.1 41.0 36.1 26.5 33.8 37.1 34.0 26.6 108 108 108 108 108 108 108 108 128 128 128 128 108 128 80 80 80 80 136 116 86 116 136 136 116 86 86 117 136 137 116 86 117 137 117 86 51 43 33 38 42 45 49 55 37 44 40 41 30 24 58 45 38 42 23 23 11 40 1 39 10 36 22 31 18 28 8 38.5 2 36 2 42 4 38 11 35 7 41 1 42 0 29 8 60 19 47 8 46 0 54 50 17.3 173.5 50 47.0 138 50 16.3 184 50 19.5 154 50 21.5 139.5 50 26.4 113.5 50 40.5 74 30 41.0 44 50 24.0 125 50 32.8 91.5 30 30.2 59.6 20 40.7 29.4 30 27.1 66.5 50 45.0 66.6 20 25.6 47 30 27.4 65.7 30 18.4 98.0 20 43.9 27.4 50 16.6 181 50 16.6 181 50 21.2 141.5 50 21.3 141 50 21.0 142.5 50 30.2 99.4 50 30.0 100 50 30.1 99.5 20 21.6 55.5 20 21.9 54.9 20 21.5 55.8 10 28.8 20.8 10 29.2 20.6 10 28.5 21.1 30 18.3 98.3 30 18.6 96.8 30 18.5 97.3 30 18.7 96.3 Q - Btu/hr.:3 27,750 27,950 - 28,200 O 27,000 - 25,950 3 23,600 - 21,400 s 16,000' 41,400 37,300 30,400 20,550 20,500 32,200 3,650 m 5,100 4,960 2,660 3 48,900 m 33,300 8,400 > 32,000 47,000 m 44,500 o 29,700 t 6,430 - 6,590 s 22,200 34,400 5 17,900 X 11,550 - 3,080 c 29,200? 42,800 28,900 7,280 113 o05 85 106 114 118 108 84 84 113 125 130 115 86 109 118 109 86

I TABLE II (Continued) -_ CY rI -1 wo Btu/hr. 3 Xo Run No. Water Temperature In Out Water H2OAT AT Corr. Freon Temperature In Out Freon Pressure In Out Freon Evap. AP Pres. Water Rate ~C ~C ~C ~C ~C ~C Psi Psi Psi Psi # Sec. #/min. Coil No. 77, Wolverine 60-115032-01, 11 fin/inch, 12 ft. 8 in. 259 260 262 263 264 f\) 265 266 267 268 269 270 278 279 398 399 400 403 404 405 406 22.10 22.00 22.11 21.91 22.00 21.95 21.91 22.12 20.05 22.33 21.90 22.00 22.00 22.00 21.95 22.10 22.05 22.00 21.98 22.05 23.98 24.43 25.70 27.19 24.61 25.50 26.61 28.52 31.65 24.93 25.30 24.92 25.50 22.60 22.65 24.10 25.00 25.65 24.58 23.00 1.88 2.43 3.59 5.28 2.61 3.55 4.70 6.40 9.60 2.60 3.40 2.92 3.5o 0.60 0.70 2.00 2.95 3.65 2.60 o.95 2.08 2.63 3.79 5.48 2.81 3.75 4.90 6.60 9.80 2.80 3.60 3.12 3.70 0.80 0.90 2.20 3.15 3.85 2.80 1.15 50.4 50.5 55.6 51.8 53.75 57.1 53.2 55,2 57.5 54.3 54.45 59.6 63.0 39.2 38.7 52.0 54.2 55.0 50.9 43.6 25.05 25.1 26.5 28.1 24.65 25.4 26.2 28.2 32.8 25.2 25.15 25.1 25.3 24.0 23.9 24.9 25.0 25.3 25.4 24.0 115 115 115 115 135 135 135 135 135 135 135 135 135 85 85 113.5 135 135 115.5 86 47.5 40 77 44 63 47 38 31 70 70 64 36 32 72 67 55 55 63 69 46 50 19.1 50 24.5 40 31.8 40 57.1 70 26.0 60 29.9 50 34.7 30 31.4 20 42.6 50 18.4 70 33.3 50 20.3 50 24.5 50 19.0 50 20.3 50 20.0 50 20.5 50 26.2 50 26.4 50 26.2 157 122.5 75.5 42.0 161.5 120.5 86.5 57.3 28.15 163 126 148 127.5 158 148 150 146.5 114.6 113.8 114.6 35,200 34, 800 30,900 24,900 49,000 48,900 45, 700 40,800 29,900 49,200 49,000 49,700 48,800 13,600 14,1400 35,600 49,700 47,600 34,400 14,300 3 76.5 77 78 82 81 80 77.5 8.5 8 35.5 53 54 35.5 8.5 m _o m, go 0 -I m 5m I-~

i TABLE II (Continued) Run No. Water Temperature In Out Water H2OAT AT Corr. Freon Temperature In Out Freon Pressure In Out Freon Evap. AiP Pres. Water Rate Q mr 0 0 < C ~C ~C ~C ~C Psi Psi Psi Psi # Sec. //min. Btu/hr. Coil No. 73, Wolverine 1960l9-01, 19 fin/inch, 4 ft. 7 in. 441 442 443 444 645 446 448 449 450 451 h52 453 454 455 456 457 458 459 460 462 L64 465 21.75 22.10 22.10 22.10 22.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00 22.00 21.97 22.00 22.00 22.00 22.00 22.00 23.65 23.30 24. 60 23.80 25.20 26o20 25.20 24.20 25.10 25.20 24.20 23.h0 25.90 26.65 23.80 22.80 22.90 24.19 25.10 26.70 24.25 23.50 23;00 1.90 1.20 2.50 1.70 3.20 2.20 3.20 2.20 3.10 3.20 2.20 1.40 3.90 2.65 1.80 0.80 0.90 2.22 3.10 4.70 2.25 1.50 1.00 2.10 1.40 2.70 1.90 3.60 2.40 3.h0 2.40 3.30 3.40 2.h0 1.60 4.10 2.85 2.00 1.00 1.10 2.42 3.30 4.90 2.45 1.70 1.20 58.0 54.0 58.5 53.0 60.0 53.0 60.0 53.0 61.0 58.5 50.0 41.5 54.6 49.7 66.0 42.65 37.0 50.4 51.3 55.0 55.9 48.8 50.0 38.0 34.6 25.0 35.0 40.2 35.5 39.5 35.0 39.4 40.6 35.8 32.2 61.6 36.2 32.0 27.0 26.0 32.2 36.8 42.2 38.6 34.8 32.0 135 114.5 135 114.5 135 114.5 130 110 130 135 115 100 135 115 100 86 86 100 115 135 135 115 100 116.5 97 121 110 126 110 122 108 121 126 107 100 130 113.5 100 86 86 100 114.5 131 120 111 100 18.5 17.5 14 6.5 9 4.5 8 2 9 9 8 0 5 1.5 0 0 0 0 0.5 4 5 0 53 50 15.6 51 50 15.7 52 50 23.5 60 50 23.6 53 20 13.8 55 20 13. 8 51 30 21.0 55 30 21.0 50 30 21.0 52 30 19.6 57 30 19.8 59 30 20.1 53 30 27.2 58 30 27.0 46 30 27.0 50 30 27.0 16 30 38.0 58 30 38.2 63 30 38.1 54 30 38.6 36 50 19.6 42 50 19.6 44 50 19.6 192.5 191.5 127.7 127.2 87.0 87.0 85.7 85.7 65.7 91.9 91.0 89.6 66.3 66.7 66.7 66.7 47.4 47.1 67.2 16.6 153 153 153 43,600 29,000 37,200 26,100 31,900 22,600 31,500 22,200 30, 500 33 800 23,600 15,500 29,200 20,500 16, 400 7,200 5,630 12,300 10,900 246,700 40,500 28,100 19,800 m -* ro So "t go m ro %A 0 =r fr+ c f-<' r^

I TABLE II (Continued) Run No. Water Temperature In Out Water H20AT AT Corr. Freon Temperature In Out Freon Pressure In Out Freon Evap. AP Pres. Water Rate Q Btu/hr. I r+ oC ~C ~C ~C ~C ~C Psi Psi Psi Psi # Sec. #/min. Coil No. 74, Wolverine 196049-01, 19 fin/inch, 5 ft. 1- in. 227 228 229 230 231 232 233 234 235 236 H- 237 238 239 240 241 242 466 467 468 469 470 471 473 474 475 476 477 478 22.02 22.00 22.00 22.00 21.98 22.05 22.10 21.90 21.90 21.90 22.08 22.10 22.10 22.00 22.00 22.00 22.00 22.00 22.10 21.90 21.90 21.90 22 07 22.07 21.98 22.10 22.10 22.10 23.40 23.60 23.87 24.20 25.18 26.75 25.07 24.12 24.50 25.52 26.67 28.15 23.10 22.70 22.50 22.45 25.00 24.10 24.00 24.60 23.20 24.50 26.97 25.62 24.62 25.80 24.65 23.90 1.38 1.60 1.87 2.20 3.20 4.70 2.97 2.22 2.60 3.62 4.59 6.05 1.00 0.70 0.50 0.45 3.00 2.10 1.90 2.70 1030 2.60 14.90 3.55 2.64 3.70 2.55 1.80 1.58 1.80 2.07 2.40 3.40 14.90 3.17 2.42 2.80 3.82 4.79 6.25 1.20 0.90 0.70 0.65 3.10 2.20 2.00 2.80 1.40 2.70 5.00 3.65 2.74 3.80 2.65 1.90 51.80 51.0 50.5 49.5 50.3 50.9 57.03 56.4 56.1 53.85 57.35 54.5 32.6 41.35 38.42 40.5 55.0 53.0 51.0 57.0 56.0 59.0 51.0 45.0 42.0 56.0 48.0 34.0 31.5 32.0 32.1 32.7 33.8 34.7 35.9 34.3 35.2 36.95 38.6 40.0 25.1 25.0 25.1 35.0 36.8 33.5 32.0 35.8 31.0 35.6 38.0 34.3 30.8 33.0 30.1 23.7 108 108 108 108 108 108 128 128 128 128 128 128 83 83 83 83 135 114 114.5 135 100 134.5 135 115 101 135 114 102 38.5 36 34 32 45 51.5 51 49 49 51 52 60 45 30 55 39 47 57 62 59 66 54 40 So 5o 5o 35 36 41 50 17.5 50 20.8 50 24.5 30 19.0 20 24.7 10 34.1 50 26.1 50 17.5 50 25.1 22 15.0 30 32.4 20 44.3 20 31065 30 25.5 30 16.3 50 24.3 50 21.8 50 21.8 50 18.3 50 18.0 50 18.1 50 17.3 50 50.5 50 50.2 50 50.0 50 31.1 30 18.6 50 31.1 171.5 144.2 122.5 94.7 48.6 17.6 115 171.5 139.5 88. 55.6 27.1 37.9 70.6 110 123 137.5 137.5 1614 166.7 166 173.5 59.4 59.8 60.0 96.5 96.9 96.5 29,300 28,050 27,400 24,600 17,850 9,300 39,400 144,800 42,200 36,300 29,000 18,250 4,900 6,860 8,320 8,640 46,000 32,600 35,400 50,L400 25,100 50,500 32,000 23,550 17,750 39,600 27,700 19,800 a o 0 _. -^ 2) 3 m o _. m m a)r 3 S" - s * m 2) I 3 =1 eC W 3* a0 VI+ -^ 113.5 104 102 111 97 110 125 111 100 121 97 100 21.5 10 12.5 2L4 3 24.5 10 4 1 14 17 2 I

TABIE II (Concluded) Run Water Temperature No. In Out oC ~C Water H20AT AT Corr. Freon Temperature In Out Freon Pressure In Out Freon Evap. AP Pres. Water Rate Q'I +k o r m) ~~C O~C ~C ~ Psi Psi Psi Psi, Sec. #/rnin. Btu/hr. Coil No. 75, Wolverine 196049-01, 19 fin/inch, 11 ft. 10i2 in. 407 408 409 410 411 H 412 414 415 416 417 418 419 420 421 422 423 424 425 22.04 21.95 21.98 220o5 21.95 22.00 22.02 21o98 22.05 22.05 22.05 21.97 22.02 22 00 22.00 21.95 22.05 21995 22.00 28.24 26.50 23.56 23.00 24.85 26.05 24.07 23.50 24.25 25.03 24.10 24.05 23.55 32.00 29.53 26.90 214.45 23.00 22.47 6.20 4.55 1.58 0.95 2.90 4.05 2.05 1.52 2.20 2.98 2.05 2.08 1.53 10.00 7.53 4.95 2.40 1.05 0.47 6.40 4.75 1.78 1.15 3.10 4.25 2.25 1.72 2.40 3.18 2.25 2.28 1.73 10.20 7.73 5.15 2.60 1.25 0.67 59.0 51.0 44.0 43.0 55.0 57.8 47.6 47.4 52.0 56.6 59.5 58.3 53.5 54.8 49.9 51.0 48.0 50.7 48.6 31.1 29.1 25.1 24.4 26.8 28.1 25.8 25.4 26.2 26.7 25.9 25.8 25.6 37.2 34.0 30.3 25.7 24.7 24.2 135 115 85 85 114 135 100.5 100 114.5 135 134.5 135 115 135 115.5 100 85 100 85 97 92 80 80 86 89 84 81.5 86 85 82 82 81 116 105 93 82 80 78 38 23 5 5 28 46 16.5 18.5 28.5 50 52.5 53 34 19 10.5 7 3 20 7 52 52 56 52.5 43.5 39 42 42 39 34 32.5 48 614 65 66 68 53 62 45 30 30.7 30 31.5 30 31.4 50 31.0 50 30.7 50 31.0 50 31.0 50 21o7 50 22.0 50 22.2 50 1500 50 15.6 50 15.6 10 24.6 10 2L.9 10 21.9 10 25.7 50 15.6 50 15.7 58.7 57.2 57.4 96.8 97.8 96.8 96.8 138 136 135 192 192 192 24.4 24.1 24.1 23.3 192 191 40,600 29,900 11,020 12,000 32,800 44,40oo 23,550 25,700 35,o00 46,500 46,700 47,300 35,900 26,900 20,100 13,400 6,560 25,900 13,800 m 3 rQ 3 ro -r 00 ~r aro Su go 70 3_. u, O cf ft r_ fl+

The University-of Michigan Engineering Research Institute TABLE III. CONDENSING WATER PRESSURE DROP Water Temp. Pressure Gauge Reading inlet outlet Manometer Reading left right AP Corr. Water Rate oc Psi Psi in. Hg in. Hg Psi # Sec. #/min. Coil No. 73, Wolverine 196049-01, 19 fin/inch, 4 ft. 7 in. 7.8 7.8 7.8 7.6 7.6 7.6 7.65 7.65 7.65 7.65 7.7 45.9 46.2 57*0 30.3 24.3 30.8 31.3 48.5 16.6 13.4 - 3.8 - 8.4 -10.0 - 5.6 - 2.0 - 1.2 + 4.3 + 8.6 +10.1 + 6.0 + 2.5 + 1.75 13.9 13.7 7.3 12.6 9.8 3.69 7.75 9 15 5.28 2.05 1.34 50 15.3 50 15.4 50 22.1 50 16.2 50 18.0 50 30.9 50 20.5 50 1900 50 25.7 50 42.6 50 5309 196 195 136 185 166o5 97 146.5 158 117 70.4 55.6 Coil No. 74, Wolverine 196049-01, 19 fin/inch, 5 ft. 11- in. 8.2 8.1 8.05 8,0 8,0 8.0 8,0 7.8 7.8 7.7 8,0 8.05 37.0 32.1 24.4 26.3 21.5 20.6 17.8 1306 14.5 11.9 - 9.0 - 7.7 - 5.95 -4.6 - 3.1 - 200 - 1.1 + 9.2 + 8.0 + 6.35 + 5.1 + 3.65 + 2.6 + 1.7 15.2 13.2 9.7 10.7 8.5 8o31 7.17 5,62 4.44 3.1 2.12 1.3 50 14.4 50 15.4 50 18.0 50 1701 5o 18.5 50 19o9 50 21,9 50 24.9 50 28.3 50 34.2 50 42.3 50 55.5 208 195 167 17505 162 151 137 120,5 106 87.7 70.9 54 Coil No. 77, Wolverine 60-115032-01, 11 fin/inch, 12 ft. 8 in, 8.5 8.4 8,4 8.35 8.35 8.4 8.5 8,5 8.55 8,6 8.7 55.5 53.5 44.8 44.3 32.5 25.4 18.6 13 2 11.3 10.5 9.1 7.6 5.9 4.3 41.1 41.o 33.1 34.0 23.8 18,4 13.2 9.37 6.86 5.17 3.85 50 17.9 50 19 5 50 20.1 50 21.6 50 23.8 50 26.9 50 3107 50 38.7 50 45.5 50 52.1 50 62.0 16705 154 149 139 126 111.5 9406 77*5 66 57.5 48.4 +10.8 - 907 + 7.9 - 7.1 + 6.05 - 5.25 + 4.6 - 3.8

The University of Michigan * Engineering Research Institute TABLE III (Continued) Water Pressure Gauge Manometer AP Water Rate Temp. Reading Reading Corr. inlet outlet left right ~C Psi Psi in. Hg in. Hg Psi # Sec. #/min. Coil No. 75, Wolverine 196049-01, 19 fin/inch, 11 ft. 102 in. 7.4 42.5 17.0 24.3 50 15.7 191 7.5 31.5 12.5 17.9 50 18.6 161 7.5 36.0 14.4 20.5 50 17.2 174 7.7 30.2 12.0 17.1 50 19.0 158 7.65 25.2 10.2 13.9 50 20.8 144 7.7 22.2 9.0 12.1 50 22.2 135 7.7 -11*3 +11.5 10.4 50 24.5 122.5 7.7 - 9.2 + 9.6 8o55 50 27.5 109 7.7 - 7.3 + 7.7 6.81 50 31.1 96,5 7.75 - 4.8 + 53 4.58 50 39.0 77 7.8 - 3.8 + 4.4 3.71 50 4307 68.6 7.8 - 2.35 + 2.95 2.39 70 77.8 54 7.9 - 1.45 + 2.15 1,62 50 68.5 4308 Coil No. 78, Wolverine 60-115032-01, 11 fin/inch, 6 ft. 7.9 45.5 16.5 27.8 50 15o8 190 7.85 46.5 16.8 28,5 50 1605 182 7.85 46.5 17.0 28.3 50 15.8 190 7.8 42.7 15.4 26.1 50 16,5 182 7.8 40.5 147 24.6 50 17.0 176,5 7.8 35.0 12.6 21.3 50 18.0 167 7.85 3000 10.9 18,0 50 20.0 150 7*9 21.7 8.2 12.4 50 23.5 128 7.9 -11.3 +11o4 10.3 50 263 114 8,0 - 7.0 + 7.4 6.6 50 3305 89.5 8.0 - 8.7 + 9.0 8.1 50 30.3 99.2 8.05 - 57 + 6.2 5.45 50 37.1 80.9 8.1 - 3.2 + 3.8 3.21 50 48.8 61.5 8.1 - 4.0 + 4.5 3.9 50 44~0 68.1 8.3 - 2.2 + 2,8 2,3 50 57.9 51.9 8.5 - 1.25 + 1.9 1,46 50 74.8 40L1 L 17

The University of Michigan Engineering Research Institute TABIE III (Concluded) Water Manometer P Water Rate Temp. Reading Corr. left right ~C in. Hg in. Hg Psi # Sec. #/min. Coil No. 79, Wolverine 60-115032-01, 11 fin/inch, 3 ft. 62 in. 708 -13.8 +13.9 12.6 50 19.5 154 7.7 -11.7 +11.9 10.75 50 20,5 146.5 7.7 -10.4 +10.7 906 50 22,4 134 7.7 - 8.0 + 8.4 7,46 50 25.0 120 7.7 - 6.2 + 6.7 5.88 50 28.6 104 7.7 - 4*4 + 5.0 4.28 50 33.7 89 7.75 - 2.9 + 3.6 2.96 50 40.9 7304 7.8 - 1.8 + 2.5 1,96 50 50.8 59 7.9 - 1.15 + 1.95 1.41 50 60.1 49.9 8.0 - 06 + 1.4 0.91 50 76.6 39.2 18

The University ot Michigan t Engineering Research Institute Fig. J. h4' 7" long 94-fBintper- inch coaxial col]..:Fig. 2 >' -JI /2" long l.9-fin-.per-:lnch coaxial. coil...0..19

The Universrtity of M~ichigan - Engineering Research Institute...... Frig. [5 lj]..' iO./2" long 19- -inper:.inch coaxial.. coils.. Fig.'.'3t6 —./2 long ll. finper-inch coaxial coi.].. 20........................

1:.. 1T *L.rE 1O,) yTWEX-YaO-Ol- qouOn t-i:9UTJXT uo{.0 9 + S{,ak f'Too o"Y't:Xo fu: - aou-f i:. T uoSh1[;:,O - 9 4 (I2$T a a - l}suI l qiamiasaj $u-laau!u! 0 UIUSUIDI W. JO AjM, —Ialln aq-.L

I The University of Michigan T Engineering Research Institute Figs 7~ Cross sectional v:..ew of the ll ofsinipers winch coil.. FIig. 8. Cross,-sectional. vuiew of the ]9ftin-per,-inch coil.:... Fi-go, 9. Compressor and condensing seetion.

----------- II~~~* ~~~ ~ -.. —I L-lliiiiiiiiillllll111111 - - Iw:C 4i. o 4-:L:I w~ I c*" 01 4-LS A) to C) C) 7-1 0 C 34):C, rt Ccd:0: C C).0 P4.s i~l: C. ~ 4-) C::~:(13 04: f:0:-~ S:: 10; Ef" E C)>. >6. 02.NN irQ1..; ~~.... ----- ~ -- I -- — 1 —-------------— I1IL^*-l--- — — —-1___1____I___ 1___1______________.-1 —1 C

I V3 FREON VAPOR -I 3t ro w =r -I 0 m S* go 3 n O ro CONDENSATE RETURN OIL SEPARATOR Fig. 12. Freon circuit.

i The University of Michigan 60 -- 56 52 48 44 40 36 - z / 32 a. / 028 // O/ 24 / 20 / / 16' // * Engineering Research Institute 0 20 40 60 80 100 120 140 160 180 200 W, LBS OF WATER/MINUTE Fig. 13. He..lt':-r.;nsfer performrn:ce of coil No. 79 (11 fins/inch - 3'-6-1/2" lon",,). ___________________________* 9 5; ) —-- ---— _ — I

The University of Michigan 60 | I I 156 - 52484440/ 36 / / 2 / 0 28 / d / / Engineering Research Institute 0! Cr I I - I I I I I I 0 20 40 60 80 100 120 140 160 180 200 W, LBS OF WATER/ MINUTE Fig. 14. Heat transfer performance of coil No. 73 (19 fins/inch - 4'-7" long). 26

i — The University of Michigan 60 - 56 52 / 48 44 / / 40 / 36/ / -2 / m 32 / Engineering Research Institute ~a z 0 I I l L v zu 40 60 80 100 120 140 W, LBS OF WATER/ MINUTE Fig. 15. Heat transfer performance of coil No. 6'-0" long). 27 78 (11 fins/inch -

The University of Michigan 60- I I I 56 52 - 48 44 / 40 / -32 / -e2 I - // za / O 28 - 0 I/ 7 Id f I Engineering Research Institute -0 20 40 60 80 100 120 140 160 180 2 W, LBS OF WATER/ MINUTE Fig. 16. Heat tr&ansfer performance of coil No. 74 (19 fins/inch - 5'-11-1/2" lone). 28

b - The University of Michigan Engineering Research Institute a sz 4 8 d I1 0 20 40 60 80 100 120 W, LBS OF WATER/MINUTE 140 160 180 200 Fig. 17. 12'-8" lor Heut transfer performance of coil No. 77 (11 fins/inch - lg). 29

The University of Michian l ngineering Research Insitut 150 Psig f f-, 7-0 / / 60 80 ~Ocz- _ I 0 Wo, LBS OF WATER/ AAIK.l &v. ~~~~Fig. 18. ~.. "'nlUE'ov 24 Heat transfer perforn f il No. 5 (19 fi 21' -1 0 nj'.1/,.O, o Wc. ( ~~j o f c o " N o - 75 ( ig fi~ ~ ~ ~ ~~ 30

The University of Michigan 60,,, * Engineering Research Institute im I-.0 - z 70 80 90 100 110 120 130 140 150 160 FREON INLET PRESSURE, PSIG Fig. 19. Heat transfer performance cross-plot for coil No. 79. 31

I The L or Iz Z d University of Michigan ~ Engineering Research Institute 60 I I I I 56 52 - 484 44 - 40 -0 36 3228 24 2016 12 8 470 80 90 100 110 120 130 140 150 160 FREON INLET PRESSURE, PSIG Fig. 20. Heat Ur-nsfer perform-nce cross-plot for coil No. 73. 32

The University of Michigan 60 ---- 56 52 48 44 40 36 - 32 z 28 0 28 I Engineering Research Institute I - 70 80 90 100 100 120 130 140 150 160 FREON INLET PRESSURE, PSIG Fig. 21. Heat transfer performance cross-plot for coil No. 78. 33

- The University of Michigan * Engineering Research Institute 60 1 1 1 1 1. -. -— 0 —-----— 34 z 0 28 Id 2420 16 12 8 4 0 70 80 90,00 110 120 130 140 150 160 FREON INLET PRESSURE, PSIG Fi>. 22. HeLiG Qransfer perform-nce cross-plot for coil No. 74. 34

The University of Michigan 60,. 56 52 -- 48 44 40 36 I og 32 z 0 28- / // Engineering Research Institute I i I I - - I I 1, I I1, -O 120 130 1-40 150 160 110 120 130 140 150 160 I00 FREON INLET PRESSURE, PSIG Fi3. 23. He.-t transfer performaince cross-plot for coil No. 77. 35 -j

The University of Michigan * Engineering Research Institute I I I I I - 32 2 z Z 0 28 3 24 20 10 70 80 90 100 110 120 130 140 150 160 FREON INLET PRESSURE, PSIG Fig. 24. Heat transfer performan ce cross-plot for coil No. 75. 36

The University of Michigan Engineering Research Institute CI z 0 d 6 I W, LBS OF WATER/ MINUTE Fig. 25. Summary of performance of four-foot coils. 37

Engineering Research Institute Qa z Ia 0 I — d 40 60 80 100 120 140 160 I1 W, LBS OF WATER/MINUTE Fig. 26. Summury of performance of six-foot coils. 200 38

EEngineering Research Institute.000 50 Psig # 77(11 fpi) 40 150 Psig # 75(19 fpi) / S~~ #511, 125 Psig # 77(11 fpi) ^ ^"^ l25 ^..7-. -.. 0 — -_ P — 125 Psig # 75(19 fpi) 100 Psig # 75(19 fpi) 85 Psio * 75099 85 Psig 77(11 fpi) iv l 120 W, LBS OF WATER/MINUTE FiP- 27. Summary of U.~ performance of tzelve-foot coils. 39

The University of Michigan 60 56 52 48 44 40 36 N 32 C3 z o 28 I60 Engineering Research Institute o0 0 2 4 6 8 LENGTH, FT 10 12 14 16 Fig. 28. Effect of length of co ~loo ro.te of 50 lbs. per minute. il on heJt lood with a constant -ater 40

The University of Michigan * Engineering Research Institute 60 —------ I i I 150 Psig (11 fpi) 56 150 Psig (19 fpi) 52 - 48 44 125 Psig (19 fpi) 40 / 125 Psig (11 fpi) 36 32 z 0 28 Effect of length of coil on heat load ith constant ater 24 100 Psig (19 fpi) 100 Psig (11 fpi) 20 16 12 8 4 0 0 2 4 6 8 I0 12 14 16 LENGTH, FT J'ig. ~2..Effect of length of coil on heat load with a constant:iater flo- rate of 100 lbs. per minute. 41 1

The University of Michigan * Engineering Research Institute 60 150 Psig (11 fpi) 56 150 Psig (19 fpi) 52 48 44 125 Psig (11 fpi) 40 125 Psig (19 fpi) 36 32 z ~0~ // /^ [~~~100 Psig (19 fpi) 24 20 100 Psig (11 fpi) 16 0 28 0 2 4 6 8 10 12 14 16 LENGTH, FT Fig. 30. Effect of length of coil on heat load with a constant water flow rate of 150 lbs. per minute. 42

i 60 50 I I I I I 11 I I I I I III I I 40 30 o) IJ IL: 0. Fn Q. <3 20 0 0 -I r" C 3 m ro,) 0 5^ 0 10 9 8 7 6 5 4 0 0) 0 0 0 A 3 2 I 0 m 3 fO fb m 0 fb 0 I I I I I 111 I IIIIII - I I 2 3 4 5 6 78910 Q,THOUSAND 20 30 40 50 60 BTU/HR 100 Fig. 31. Summary of pressure drop data for the four-foot coils. [0 coil No. 75 (19 fins/inch)] [A coil No. 79 (11 fins/inch)] _J

- --- ---- 60 50 I I I I I I I I I I I I I I I I I I f I I 1 1 I I I 1 1 I I I i 1 1 1 I I 40 30 - 20 - w 0 U) z 0 ItJ - 10 9 c 8 a. 7 o 6 5 -I. cr m ro -' m I,-< 0 _. m, 2) 0 4z4=-' 4 3 2 0 0 rn m 3 S" _.:r ro 70 3 %A m -r cb _. fl+ r_ Q) rp I I I I I I, I A, I I I I I I I I I I I I 2 3 4 5 6 7 89 10 20 Q, THOUSAND BTU/HR 30 40 50 60 80 100'ig. )2. Summ-ry of pressure drop d.ta for the six-foot coils. [0 coil No. 74 (19 iins/inch)] [A coil No. 78 (11 fins/inch)] I

- 60 50 40 30 W 20 C) z 0 w or U10 c) 9 n o2 8 0. 7 6 5 I I 111 I I! 1111 ASo /0 / o ~/ - I C: rt'" m 0. r) =. 33 I I o1 4 3 - 2 F 3 m~ S1 ro w Io cu ft I I I I I I 11 III I Il i I I I I I l 2 3 4 5 6 7 8 9 10 20 Q,THOUSAND BTU/HR 30 40 50 60 80 100 Fig. 33. Summary of pressure drop data for the twelve-foot coils. [0 coil No. 75 (19 fins/inch)] [A coil No. 77 (11 fins/inch)]

1 200 180 160 140 120 I I I I I I l! I I I I I 1 _ 100 h 80 H I I II i i i -'1 r:3 C3 _. ro <a OK 2) 1/3 7A a. =3 60 - 40 m m 3 _, oQ 3 "'1 -I n OQ I I I 1 I I I I I I I I I I I 20 0.1 0.2 0.3 0.4 0.5 0.6 08 1.0 2.0 3.0 4.0 5.0 6.0 8.0 10.0 WATER RATE (POUNDS/MIN) Fig. 34..ater side pressure drop for coil No. 79 (11 fins/inch - 3'-6-1/2" long). I

-I M 0 4% 0 wc S VA 0. aCL m 3 3o ft'o Q m, an "'"' I 2 3 4 5 6 7 8 9 10 15 20 30 40 50 60 708090100 WATER RATE (POUNDS/MIN) Fig. 35. U..ter side pressure drop for coil No. 73 (19 fins/inch - 4'-7" long).

1 200 180 160 - 140 120 - 1001 I I I I I I. I I I I I 80 - V) %. CL q 60 - -4 =r rm m, r+ n =1 0 3 <0 0 3O 40 - I4 I i I I8 0 1 40 50 60 70 8090 1C I I I I I I I I I 201 I 2 3 4 5 6 7 8 9 10 15 20 30 WATER RATE (POUNDS/MIN) Fig. 36. Water side pressure drop for coil No. 78 (11 fins/inch - 6'-0" long). -------— 4

200 180 160 140 120 I- - I I - -I I I I I 100 - 80 -,C Q. qq I I I I I I I I I I I -,I =1 m ro:C 3 rI rt it\ 0 60 4-,\10 40 - I - I I I I III I. 20 I 2 3 4 5 6 7 8 9 10 15 20 30 40 50 60 70 8090100 m 3 3 co 73 m, ": go c. ~-** a^ WATER RATE (POUNDS/MIN) Fig. 37..iater side pressure drop for coil No. 74 (19 fins/inch - 5'-11-1/2" long). I

i 200 180 160 140 120 I I I I I I I I I1 * *...I I I I I I I Il 100 - 80 - U-. " 60,q I I I I I I I I I I I I I I -I Yb C::3 -1 m, O 0: _, w So as 3 40 m 3 so -I 3;r 0) o I I I I I I I I I 20 I 2 3 4 5 6 7 8 9 10 15 20 WATER RATE (POUNDS/ MIN) 30 40 50 60 70 8090 100 Fig. 38. Water side pressure drop for coil No. 77 (11 fins/inch - 12'-8" long). --------- -a

200 180 160 140 120 100 I I I I I I I I I II I I I I I I I I I I I I I I I I I I I I -I C I, 0 r+ 0 EI) 80 - 60 In ^<J1 401 m gor Ir 70 n, =1 I I I I I I I I I I I I I I I II 20 I 2 3 4 5 6 7 WATER 8 9 10 15 RATE (POUNDS / MIN) 20 30 40 50 60 70 8090100 Fig. 39. Later side pressure drop for coil No. 75 (19 fins/inch - 11'-10-1/2" long). I