Document gDn8joNKrmbr0DZaxMRmrbQyG

HEATING VENTILATING AIR CONDITIONING GUIDE 1943 Table 12. Suggested Solar Heater Design Data3 Design Item Based on .Rate op 30 Gal pee Dat peb Pebson Based on Rate op 40 Gal peb Dat peb Pebson No Occupants in Residence........ -- 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Hot Water Used at Night, gal per person,....... ............. -.................... 15 15 15 15 15 15 15 15 20 20 20 20 20 20 20 20 Hot Water Used at Night, gal total-- 15 30 45 60 75 90 105 120 20 40 60 80 100 120 140 160 Retained in Tank, 25 per cent, gal----- 4 8 11 15 19 23 27 30 5 10 15 20 25 30 35 40 Tank Capacity Required, gal........-- 20 40 59 75 94 113 130 150 25 50 75 100 125 150 175 200 Hot Water Used During Day, gal..... 15 30 45 60 75 00 :105 120 20 40 GO 80 100 120 140 160 Total-Water to be Heated: 35 70 104 135 169 203 235 270 45 00 135 ISO 225 270 315 360 Gal per hour................................... 4.5 9 13 17 21 26 29 34 6 12 17 23 28 34 39 45 Copper Coil Required: 25 50 75 100 121 145 168 192 32 64 96 128 .160 192 224 256 Equivalent length 1 in. coil, ft....... 100 200 300 400 484 680 664 768 128 256 384 512 640 '768 '896 1024 Box Sise: Area, sq ft................................ -- 25 50 75 100 121 145 168 192 32 64 96 128 160 192 224 256 Width, ft........................................ 4 6 7 8 . S 1(1 10 11 4 6 8 (I 16 11 12 12 Length, ft....................................... 6 8 11 12.5 13.5 14.5 16.5 17.5 -8 10 . 12 14 16 18 19 21 aSun Effect and the Design of Solar Heaters, by H. L.- Alt (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 131). coil, circulation lines and tank. The coil should be inclined as shown in Fig. 11 so that the north end is raised above the south end to secure an angle with the horizontal of about 53 deg. This will result in the inlet end of the coil being on the south side (or bottom) and the outlet end being on the north side (or top). This will satisfy conditions along the 30 deg N latitude which includes the portions of Florida and Southern California where these heaters are most frequently used. The hot box is usually constructed of wood on the four sides and bottom and is insulated. Over the top of the box glass sash are placed and the box should be constructed as near air tight as possible. The interior surfaces should be painted white to reflect the heat while the coil should be painted black to absorb the heat. The box need not be deeper than necessary to house the coil and to protect it from the weather. The addition of a light gage copper plate on the bottom of the box to which the pipe of the coil is soldered, for good metallic contact, will add to the amount of heat received by the coil due to the fact that this plate will receive all of the sun rays which fail to directly strike the coil. The heat from this source is transmitted to the coil through the plate instead of by heating the air surrounding the coil and from which only part of the heat enters, the coil, the.balance being transmitted through the glass sash. Design data given in Table 12 may be used with some judgment in .'selecting the size of solar heater coil and box for a particular application. : "These' data are based on consumptions of 30 and 40 gal of hot water per day per person. 842 Chapter 47 TERMINOLOGY Glossary of Physical and Heating, Ventilating, Refrigerating and Air Conditioning Terms Used in the Text Absolute Humidity: See Humidity. Absolute Pressure: The pressure referred to that of a perfect vacuum. It is the sum of gage pressure and barometric pressure. . Absolute Temperature: A reading on the absolute temperature scale. Absolute temperature is obtained by adding 459.70 degrees to the Fahrenheit temperature. . Absolute Zero: The zero point on the absolute scale 459.70 F below the zero of the Fahrenheit scale. Acceleration: The rate of change of velocity. In the fps system this is expressed in units of one foot per second, a = V 4- t. Acceleration Due to Gravity: The rate of gain in velocity of a freely falling body, the value of which varies with latitude and elevation. The international gravity standard has the value of 980.665 cm per second per second or 32.174 ft per second per second, which is the actual value of this acceleration at sea level and about 45 deg latitude. Adiabatic: An adjective descriptive of a process in which no heat is added to or extracted from the system executing the process. Air Cleaner: A device designed for the purpose of removing air-borne impurities such as dusts, fumes and smokes. (Air cleaners include air washers and air filters.) Air Conditioning: The simultaneous control of all or at least the first three of those factors affecting both the physical and chemical conditions of the atmosphere within any structure. These factors include temperature, humidity, motion, distribution, dust, bacteria, odors and toxic gases, most of which affect in greater or lesser degree human health or comfort. (See Comfort Air Conditioning.) Air Washer: An enclosure in which air is forced through a spray of water in order to cleanse, humidify, or dehumidify the air. Anemometer: An instrument for measuring the velocity of moving air. Atmospheric Pressure: The pressure indicated by a barometer. Standard atmospheric pressure is a pressure of 76 cm mercury (density 13.5951 grams per cubic centimeter, gravity 980.665 cm per second per second). It is equivalent to 14.6959 lb per. square inch or 29.921 in. of mercury at 32 F. Baffle: A plate or wall for deflecting gases or fluids. Blast: This word was formerly used to denote forced air circulation, particularly in connection with central fan systems using steam or hot water as the heating medium. As applied in this sense, the word blast is now obsolete. Boiller: A closed vessel in which steam is generated or in which water is heated.. Boiler Heating Surface: That portion of the surface of the heat-transfer apparatus in contact with the fluid being heated on one side and the gas or refractory being cooled on the other, in which the fluid'being heated forms part of the circulating system; this surface shall be measured on the side receiving heat. This includes the boiler, water walls, water screens, and water floor. {A.S.M.E. Power Test Codes, Series 1929.) Boiler Horsepower: The equivalent evaporation of 34.5 lb of water per hour from and at 212 F. This is equal to a heat output of 970.3 X 34.5 = 33,475 Btu per hour. British Thermal Unit: A unit of energy defined in terms of the .international .steamtable calorie through the convenient relation 1 Btu per pound per degree.Fahrenheit = 1 cal per gram per degree Centigrade. It is approximately the quantity of heat required to raise the temperature of 1 lb of liquid water from 63 to 64 F. 843