Document 1g9mqyOw1QLX0M1D9Qedxgw3q

654 CHAPTER 37 1948 Guide Table 1. Average Maximum Water Main Temperatures* T bmp. F T emp. F State City State City Cs< eu . aS. State h City Ala. Ariz. Calif. Colo. Conn. D. C. Del. Fla. Ga. 111. Ind. Iowa Kans. Ky. La. Me. Md. Mass. 84 Mobile________ 73 Phoenix_______ 81 Tucson________ .80 Anaheim______ 60 Berkeley. 69 Fresno.________ 72 Fullerton...... 75 6$ Los Angeles___ 75 Oakland............ 69 Ontario_______ 70 82 Pomona...... .... 75 Riverside_____ 78 Sacramento...... 72 San Bernardino 65 San Diego...... .. 82 San Francisco.. 62 75 Denver________ 75 Bridgeport____ 66 Hartford____ __ 73 New Haven___ 76 Waterbury____ 72 Washington___ 84 Wilmington___ 83 Jacksonville___ 80 Miami_________ 80 Tampa_____ '.__ 77 87 80 Cicprn ........ 76 76 Evanston_____ 73 Peoria_________ 67 Rockford___ .... 59 Springfield____ 82 Evansville_____ 86 75 Indianapolis.__ 80 South Bend___ 61 Terre Haute.__ 82 Cedar Rapids.. 78 Des Moines___ 77 Sioux City____ 62 Concordia_____ 57 Kansas City.__ 86 Topeka________ 88 Wichita________ 72 85 Baton Rouge... 85 New Orleans__ 85 60 Baltimore.____ 75 Boston....... .. ... 80 Cambridge. 70 Fall River_____ 76 Mich: Lynn_____ ___ _ New Bedford__ Salem__ ......___ Worcester:_____ Detroit_______ : Flint__________ Grand Rapids.. Jackson. __: Kalamazoo.___ Lansing._______ Minn. Duluth.............. Minneapolis__ _ St. Paul........ ,, Mo. Jefferson City.. Kansas City.__ St. Joseph_____ Nebr. Nev. N. H. N. J. N. Y. Springfield____ Lincoln. . .. Omaha...... .. ... Reno .. ____ Manchester...... lersev Citv.___ Newark. ___ Paterson_______ Trenton............. Albany________ New York___ ... Rochester.......... Schenectady___ Syracuse^______ Utica............. ..... N. C. N.M. Ohio Asheville.______ Charlotte______ Winston-Salem Albuquerque.... Akron_________ Canton Cincinnati:........ Cleveland_____ Columbus.____ Dayton. ___ Okla. Ore. Springfield____ 1 oledo............... Tulsa__________ Eugene._______ Portland_______ 50 Pa. 74 68 Erie.___________ 75 70 Johnstown____ 74 68 McKeesport___ 82 76 Philadelphia___ 83 77 Pittsburgh____ 81 70 R. I. Providence. 68 84 S. C. Charleston. ... 80 77 81 56 Spartanburg.__ 78 53 S. D. Rapid City____ 55 64 Tenn. Chattanooga..;. 84 82 89 55 Memphis_____ :. 70 80 Nashville______ 90 77 Texas Amarillo.____ ... 65 82 Austin_________ 90 84 Beaumont..... 86 84 Dallas.. ____ 86 85 84 70 Galveston___ .... 90 63 Houston_______ 84 87 Port Arthur.. 83 61 San Antonio.__ 76 76 Wichita Falls... 85 63 Utah Logan________ 44 74 Salt Lake City.. 60 78 Va. Fredericksburg 75 79 Lynchburg.____ 73 68 Norfolk._______ 80 75 1 Wash. 58 56 62 74 51 75 57 72 W.Va. Charleston____ 85 70 Huntington...... 78 60 Wheeling........... 78 74 Wis; LaCrosse........... 54 69 Madison.______ 58 70 70 74 Racine....:_____ 68 85 82 65 -- 76 50 84 74 82 -- -- 60 82 Alta. 64 72 B. C. Vancouver____ 60 83 Ont. London________ 50 82 63 85 P.E.I. Charlottetown.. 48 60 Que. Montreal........ .. 78 64 Quebec________ 68 &These averages taken from various city water main locations, with some actual values slightly higher and some lower than values shown. Spray Apparatus 655 point of the mixture should move in a direction determined by the specific enthalpy of the heated spray as explained in Chapter 3. It is possible, by elevating the water temperature, to raise the aii* temperature, both dry-bulb and wet-bulb, above the dry-bulb temperature of the entering air. In each of the methods, 1, 2 or 3, the air leaving the air washer may require reheating to produce in the conditioned space the required drybulb temperature and relative humidity. DEHUMIDIFICATION AND COOLING WITH AIR WASHERS Cooling of the wet-bulb temperature of an air vapor mixture can be, accomplished by an air washer if the temperature of the spray water is lower than the wet-bulb temperature of the air. Moisture removal is obtained when the spray water temperature is lower than the dew-point of the entering air. In these cases the final dry-bulb temperature and relative humidity of the leaving air are dependent fipon the design factors of the air washer. Both sensible and latent heat are removed in the process of dehumidi fication by cold spray water. Abstraction of sensible heat occurs during the entire time that the air is in contact with the spray medium. Latent heat removal takes place as condensation occurs. Therefore, the lower the spray temperature the greater the amount of moisture removal per pound of dry air, all other conditions remaining the same. Washers with two or more banks of spray are usually selected for dehumidifying installations, whether for comfort or industrial instal lations. Generally such air washers cool the air to within one or two degrees (Fahrenheit) of the leaving spray water temperature; this dif ferential will increase somewhat when the difference between the entering wet-bulb and leaving dew-point is relatively large. Where a limited supply of cold water is available multiple stage washers may be used to great advantage. In such washers the cool water is pumped through the multiple spray systems in series and counterflow to the air flow. Such an arrangement brings the delivery air in contact with the coldest water, securing a maximum amount of cooling with economy of water. When using cold well water or water from city water mains care should be used to secure accurate data on the water temperatures. Table 1 lists . some approximate water main averages which may be used as a guide but; they should be verified from local records. This is particularly true with city water main temperatures. In the case of well water temperatures Fig. 3 shows the approximate temperatures of water to be expected from wells at depths' of 30 to 60 ft. Air washers for dehumidifying and cooling usually have separate recirculating pumps. These pumps deliver a mixture of cold and re circulated water under the control of a three-way valve. The valve may be actuated either by a thermostat in the washer outlet or by a humidity or other controller in the space being conditioned. Air washers for dehumidifying are very often furnished with direct expansion or water cooling coils within the washer space, in which case water for the washer sprays is entirely recirculated. APPARATUS FOR DIRECT HUMIDIFICATION Humidifiers may be divided into the following general types, according to the method of operation: (1) indirect, such as the air washer, which