1、14.1CHAPTER 14INDUSTRIAL AIR CONDITIONINGGeneral Requirements 14.1Process and Product Requirements . 14.1Personnel Requirements. 14.4Design Considerations. 14.5Load Calculations 14.6Pressurization 14.6System and Equipment Selection . 14.7Heating Systems. 14.7Cooling Systems . 14.7Air Filtration Syst
2、ems. 14.8Exhaust Systems . 14.8Operation and Maintenance. 14.8Heat Recovery and Energy Conservation 14.9Life and Property Safety. 14.9Control Systems 14.9Commissioning. 14.9HIS chapter addresses air-conditioning systems for industrialTfacilities such as manufacturing plants, laboratories, processing
3、plants, and power plants. HVAC systems provide the process envi-ronment (including temperature, humidity, air motion, air quality,noise, and cleanliness) to facilitate industrial processes and providefor the health, safety, and comfort of personnel.Many industrial buildings require large amounts of
4、energy, inboth manufacturing and maintaining building environmental condi-tions. This chapter provides system and building design guidance forenergy conservation by using insulation, ventilation, and waste heatrecovery.1. GENERAL REQUIREMENTSTypical temperatures, relative humidities, and specific fi
5、ltrationrequirements for storage, manufacture, and processing of variouscommodities are listed in Table 1. Requirements for a specific appli-cation may differ from those in the table.Industrial processes or regulatory requirements may change overtime; thus, systems should be able to provide for futu
6、re requirementsto the extent this is practical.Outdoor design requirements and indoor temperature, humidity,cleanliness, noise, and allowable variations should be established byagreement with the owner. A compromise between requirements forproduct or process conditions and those for comfort may opti
7、mizequality and production costs.An environment that allows a worker to safely perform assignedduties without fatigue from the effects of temperature and humiditymay enhance performance.Special Warning: Some industrial spaces may contain flamma-ble, combustible, and/or toxic concentrations of vapors
8、 or dustsunder either normal or abnormal conditions. In spaces such as these,there are safety issues that this chapter may not completely address.Special precautions must be taken in accordance with requirementsof recognized authorities such as the National Fire Protection Asso-ciation (NFPA), the O
9、ccupational Safety and Health Administration(OSHA), and the American National Standards Institute (ANSI). Inall situations, engineers, designers, and installers who encounterconflicting codes and standards must defer to the code or standardthat best addresses personnel safety.2. PROCESS AND PRODUCT
10、REQUIREMENTSAn industrial product or process may require control of the indoorenvironment if it affects one or more of the following factors.Rate of Chemical ReactionSome processes require temperature and humidity control to reg-ulate chemical reactions. In rayon manufacturing, for example, pulpshee
11、ts are conditioned, cut to size, and mercerized. The temperaturedirectly controls the rate of reaction, and the relative humidity main-tains the solution at a constant strength and rate of evaporation.In drying varnish, oxidizing depends on temperature. Desirabletemperatures vary with the type of va
12、rnish. High relative humidityretards surface oxidation and allows internal gases to escape aschemical oxidizers cure the varnish from within. Thus, a bubble-free surface is maintained with a homogeneous film throughout.Rate of CrystallizationThe cooling rate determines the size of crystals formed fr
13、om asaturated solution. Both temperature and relative humidity affect thecooling rate and change the solution density by evaporation.In coating pans for pills, a heavy sugar solution is added to thetumbling mass. As water evaporates, sugar crystals cover each pill.Moving the correct quantity of air
14、over the pills at the correct tem-perature and relative humidity forms a smooth, opaque coating. Ifcooling and drying are too slow, the coating will be rough, translu-cent, and have an unsatisfactory appearance. If the cooling and dry-ing are too fast, the coating will chip through to the interior.R
15、ate of Biochemical ReactionFermentation requires both temperature and humidity control toregulate the rate of biochemical reactions. Many fermentation ves-sels are jacketed to maintain consistent internal temperatures. Fer-mentors are held at different temperatures, depending on the processinvolved.
16、 In brewing, typical fermentor temperatures range from 45to 52F. Because of vessel jacketing, tight control of room temper-ature may not be required. Usually, space temperatures should beheld as close as practical to the process temperature inside the fer-mentation vessel.Designing such spaces shoul
17、d take into account gases and otherby-products generated by fermentation. Typically, carbon dioxide isthe most prevalent by-product of fermentation in brewing and pres-ents the greatest potential hazard if a fermentor overpressurizes theseal. Provide adequate ventilation in case carbon dioxide escap
18、es theprocess.In biopharmaceutical processes, hazardous organisms can escapea fermentor; design of spaces using those fermentors should allowcontainment. Heat gains from steam-sparged vessels should also beaccounted for in such spaces.Product Accuracy and UniformityAir temperature and cleanliness af
19、fect quality in manufacturingprecision instruments, lenses, and tools. When manufacturing toler-ances are within 0.0002 in., close temperature control (typicallyThe preparation of this chapter is assigned to TC 9.2, Industrial Air Condi-tioning.14.2 2015 ASHRAE HandbookHVAC ApplicationsTable 1 Desig
20、n Requirements for Industrial Air Conditioning1Process Dry Bulb, F rh, % Process Dry Bulb, F rh, %ABRASIVE FOUNDRIES*Manufacture 79 50 Core making 60 to 70CERAMICS Mold makingRefractory 110 to 150 50 to 90 Bench work 60 to 70Molding room 80 60 to 70 Floor work 55 to 65Clay storage 60 to 80 35 to 65
21、Pouring 40Decalcomania production 75 to 80 48 Shakeout 40 to 50Decorating room 75 to 80 48 Cleaning room 55 to 65Use high-efficiency (MERV 13 or better) in decorating room. To mini-mize the danger of silicosis in other areas, a dust-collecting system ormedium-efficiency particulate air filtration ma
22、y be required.*Winter dressing room temperatures. Spot coolers are sometimes used in largerinstallations.In mold making, provide exhaust hoods at transfer points with wet-collector dust removal system. Use 600 to 800 cfm per hood, with a targetcapture velocity of approximately 500 fpm.In shakeout ro
23、om, provide exhaust hoods with wet-collector dustremoval system. Exhaust 400 to 500 cfm in grate area. Room ventilators aregenerally not effective.In cleaning room, provide exhaust hoods for grinders and cleaningequipment with dry cyclones or bag-type collectors. In core making, ovenand adjacent coo
24、ling areas require fume exhaust hoods. Pouring roomsrequire two-speed powered roof ventilators. Design for minimum of 2 cfmper square foot of floor area at low speed. Shielding is required to controlradiation from hot surfaces. Proper introduction of air minimizes preheatrequirements.DISTILLINGGener
25、al manufacturing 60 to 75 45 to 60Aging 65 to 72 50 to 60Low humidity and dust control are important where grains are ground.Use high-efficiency filtration for all areas to prevent mold spore and bacteriagrowth. Use ultrahigh-efficiency filtration where bulk flash pasteurization isperformed.ELECTRIC
26、AL PRODUCTSElectronics and x-rayCoil and transformer winding 72 15Semiconductor industry 70 45Electrical instruments FURManufacture and laboratory 70 50 to 55 Drying 110Thermostat assembly and calibration 75 50 to 55 Shock treatment 18 to 20Humidistat assembly and calibration 75 50 to 55 Storage 40
27、to 50 55 to 65Small mechanisms Shock treatment or eradication of any insect infestations requires lower-ing the temperature to 18 to 20F for 3 to 4 days, then raising it to 60 to 70Ffor 2 days, then lowering it again for 2 days and raising it to the storage tem-perature.Furs remain pliable, oxidatio
28、n is reduced, and color and luster are pre-served when stored at 40 to 50F.Humidity control is required to prevent mold growth (which is prevalentwith humidities above 80%) and hair splitting (which is common withhumidities lower than 55%).Close tolerance assembly 72* 40 to 45Meter assembly and test
29、 75 60 to 63SwitchgearFuse and cutout assembly 73 50Capacitor winding 73 50Paper storage 73 50Conductor wrapping with yarn 75 65 to 70Lightning arrester assembly 68 20 to 40 GUMThermal circuit breakers assembly and test 75 30 to 60 Manufacturing 77 33High-voltage transformer repair 79 5 Rolling 68 6
30、3Water wheel generators Stripping 72 53Thrust runner lapping 70 30 to 50 Breaking 73 47Rectifiers Wrapping 73 58Processing selenium and copper oxide plates 73 30 to 40*Temperature to be held constant.Dust control is essential in these processes. Minimum control requiresmedium-efficiency filters (MER
31、V 11 or better). Degree of filtration dependson the type of function in the area. Smaller tolerances and miniature compo-nents suggest high-efficiency particulate air (HEPA) filters.LEATHERDrying 68 to 125 75Storage, winter room temperature 50 to 60 40 to 60After leather is moistened in preparation
32、for rolling and stretching, it isplaced in an atmosphere of room temperature and 95% relative humidity.Leather is usually stored in warehouses without temperature and humiditycontrol. However, it is necessary to keep humidity sufficiently low to preventmildew. Medium-efficiency particulate air filtr
33、ation is recommended for finefinish.FLOOR COVERINGLinoleumMechanical oxidizing of linseed oil* 90 to 100Printing 80Stoving process 160 to 250*Precise temperature control required. LENSES (OPTICAL)Medium-efficiency particulate air filtration is recommended for thestoving process.Fusing 75 45Grinding
34、80 80Industrial Air Conditioning 14.35F prevents expansion and contraction of the material; constanttemperature over time is more important than the temperaturelevel. Usually, conditions are selected for personnel comfort andto prevent a film of moisture on the surface. A high-efficiency par-ticulat
35、e air (HEPA) or ultralow-penetration air (ULPA) filter maybe required.Product FormabilityManufacturing pharmaceutical tablets requires close control ofhumidity for optimum tablet formation. Tableting typically requiresless than 40% rh at 68F.Moisture RegainAir temperature and relative humidity marke
36、dly influence pro-duction rate and product mass, strength, appearance, and quality inmanufacturing or processing hygroscopic materials such as textiles,paper, wood, leather, and tobacco. Moisture in vegetable and animalmaterials (and some minerals) reaches equilibrium with moisture inthe surrounding
37、 air by regain (the percentage of absorbed moisturein a material compared to that materials bone-dry mass). For exam-ple, if a material sample with a mass of 5.5 lb has a mass of only5 lb after thorough drying under standard conditions of 220 to230F, the mass of absorbed moisture is 0.5 lb, 10% of t
38、he sam-ples bone-dry mass. Therefore, the regain is 10%.Table 2 lists typical regain values for materials at 75F in equilib-rium at various relative humidities. Temperature change affects therate of absorption or drying, which generally varies with the thick-ness, density, and nature of the material
39、. Sudden temperature changescause slight changes in regain even with fixed relative humidity, butthe major change occurs as a function of relative humidity.Hygroscopic materials deliver sensible heat to the air in anamount equal to the latent heat of the absorbed moisture. TheTable 1 Design Requirem
40、ents for Industrial Air Conditioning1(Continued )Process Dry Bulb, F rh, % Process Dry Bulb, F rh, %MATCHES PLASTICSManufacture 72 to 73 50 Manufacturing areasDrying 70 to 75 60 Thermosetting molding compounds 80 25 to 30Storage 60 to 63 50 Cellophane wrapping 75 to 80 45 to 65Water evaporates with
41、the setting of the glue. The amount of water evapo-rated is 18 to 20 lb per million matches. The actual match production ratemust be known to determine the actual moisture load in the space.In manufacturing areas where plastic is exposed in the liquid state ormolded, high-efficiency particulate air
42、filters may be required. Dust collectionand fume control are essential.PAINT APPLICATION PLYWOODLacquers: Baking 300 to 360 Hot pressing (resin) 90 60Oil paints: Paint spraying 60 to 90 80 Cold pressing 90 15 to 25The required air filtration efficiency depends on the painting process. Onfine finishe
43、s, such as car bodies, high-efficiency particulate air filters arerequired for the outdoor air supply. Other products may require only low- ormedium-efficiency filters.Makeup air must be preheated. Spray booths must have 100 fpm facevelocity if spraying is performed by humans; lower air quantities c
44、an beused if robots perform spraying. Ovens must have air exhausted to maintainfumes below explosive concentration. Equipment must be explosion-proof.Exhaust must be cleaned by filtration and solvents reclaimed or scrubbed.RUBBER-DIPPED GOODSManufacture 90Cementing 80 25 to 30*Dipping surgical artic
45、les 75 to 80 25 to 30*Storage prior to manufacture 60 to 75 40 to 50*Testing laboratory 73 50*Dew point of air must be below evaporation temperature of solvent.Solvents used in manufacturing processes are often explosive and toxic,requiring positive ventilation. Volume manufacturers usually install
46、a solventrecovery system for area exhaust systems.PHOTO STUDIODressing room 72 to 74 40 to 50Studio (camera room) 72 to 74 40 to 50Film darkroom 70 to 72 45 to 55 TEAPrint darkroom 70 to 72 45 to 55 Packaging 65 65Drying room 90 to 100 35 to 45Ideal moisture content is 5 to 6% for quality and mass.
47、Low-limit moisturecontent for quality is 4%.Finishing room 72 to 75 40 to 55Storage room (black and white film and paper) 72 to 75 40 to 60 TOBACCOStorage room (color film and paper) 40 to 50 40 to 50 Cigar and cigarette making 70 to 75 55 to 65*Motion picture studio 72 40 to 55 Softening 90 85 to 8
48、8The above data pertain to average conditions. In some color processes,elevated temperatures as high as 105F are used, and a higher room temper-ature is required.Conversely, ideal storage conditions for color materials necessitate refrig-erated or deep-freeze temperatures to ensure quality and color
49、 balance whenlong storage times are anticipated.Heat liberated during printing, enlarging, and drying processes isremoved through an independent exhaust system, which also serves thelamp houses and dryer hoods. All areas except finished film storage requirea minimum of medium-efficiency particulate air filters.Stemming and stripping 75 to 85 70 to 75Packing and shipping 73 to 75 65Filler tobacco casing and conditioning 75 75Filter tobacco storage and preparation 77 70Wrapper tobacco storage and conditioning 75 75*Relative humidity fairly constant with range as set by cigare
