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 7 to11C. Because of vessel jacketing, tight control of room temperaturemay not be required. Usually, space temperatures should be held asclose as practical to the process temperature inside the fermentationvessel.Designing such spaces should tak
17、e 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 escapes th
18、eprocess.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 affect
19、quality in manufactur-ing precision instruments, lenses, and tools. When manufacturingtolerances are within 5 m, close temperature control (typicallyThe preparation of this chapter is assigned to TC 9.2, Industrial Air Condi-tioning.14.2 2015 ASHRAE HandbookHVAC Applications (SI)Table 1 Design Requi
20、rements for Industrial Air Conditioning1Process Dry Bulb, C rh, % Process Dry Bulb, C rh, %ABRASIVE FOUNDRIES*Manufacture 26 50 Core making 16 to 21CERAMICS Mold makingRefractory 43 to 66 50 to 90 Bench work 16 to 21Molding room 27 60 to 70 Floor work 13 to 18Clay storage 16 to 27 35 to 65 Pouring 4
21、Decalcomania production 24 to 27 48 Shakeout 4 to 10Decorating room 24 to 27 48 Cleaning room 13 to 18Use 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 may be requir
22、ed.*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 280 to 380 L/s per hood, with a targetcapture velocity of approximately 2.5 m/s.In shakeout room, provide
23、 exhaust hoods with wet-collector dust removalsystem. Exhaust 190 to 240 L/s in grate area. Room ventilators are generallynot effective.In cleaning room, provide exhaust hoods for grinders and cleaning equip-ment with dry cyclones or bag-type collectors. In core making, oven andadjacent cooling area
24、s require fume exhaust hoods. Pouring rooms requiretwo-speed powered roof ventilators. Design for minimum of 10 L/s of floorarea at low speed. Shielding is required to control radiation from hot sur-faces. Proper introduction of air minimizes preheat requirements.DISTILLINGGeneral manufacturing 16 t
25、o 24 45 to 60Aging 18 to 22 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.ELECTRICAL PRODUCTSElectronic
26、s and x-rayCoil and transformer winding 22 15Semiconductor industry 21 45Electrical instruments FURManufacture and laboratory 21 50 to 55 Drying 43Thermostat assembly and calibration 24 50 to 55 Shock treatment 8 to 7Humidistat assembly and calibration 24 50 to 55 Storage 4 to 10 55 to 65Small mecha
27、nismsShock treatment or eradication of any insect infestations requires lower-ing the temperature to 8 to 7C for 3 to 4 days, then raising it to 16 to21C for 2 days, then lowering it again for 2 days and raising it to the stor-age temperature.Furs remain pliable, oxidation is reduced, and color and
28、luster are pre-served when stored at 4 to 10C.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 22* 40 to 45Meter assembly and test 24 60 to 63SwitchgearFuse an
29、d cutout assembly 23 50Capacitor winding 23 50Paper storage 23 50Conductor wrapping with yarn 24 65 to 70Lightning arrester assembly 20 20 to 40 GUMThermal circuit breakers assembly and test 24 30 to 60 Manufacturing 25 33High-voltage transformer repair 26 5 Rolling 20 63Water wheel generators Strip
30、ping 22 53Thrust runner lapping 21 30 to 50 Breaking 23 47Rectifiers Wrapping 23 58Processing selenium and copper oxide plates 23 30 to 40*Temperature to be held constant.Dust control is essential in these processes. Minimum control requiresmedium-efficiency filters (MERV 11 or better). Degree of fi
31、ltration dependson the type of function in the area. Smaller tolerances and miniature compo-nents suggest high-efficiency particulate air (HEPA) filters.LEATHERDrying 20 to 52 75Storage, winter room temperature 10 to 16 40 to 60After leather is moistened in preparation for rolling and stretching, it
32、 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 filtration is recommended for finef
33、inish.FLOOR COVERINGLinoleumMechanical oxidizing of linseed oil* 32 to 38Printing 27Stoving process 70 to 120*Precise temperature control required. LENSES (OPTICAL)Medium-efficiency particulate air filtration is recommended for thestoving process.Fusing 24 45Grinding 27 80Industrial Air Conditioning
34、 14.32.8 K prevents expansion and contraction of the material; con-stant temperature over time is more important than the tempera-ture level. Usually, conditions are selected for personnel comfortand to prevent a film of moisture on the surface. A high-efficiencyparticulate air (HEPA) or ultralow-pe
35、netration air (ULPA) filtermay be required.Product FormabilityManufacturing pharmaceutical tablets requires close control ofhumidity for optimum tablet formation. Tableting typically requiresless than 40% rh at 20C.Moisture RegainAir temperature and relative humidity markedly influence pro-duction r
36、ate 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 air by regain (the percent
37、age of absorbed moisturein a material compared to that materials bone-dry mass). For exam-ple, if a material sample with a mass of 2.5 kg has a mass of only2.25 kg after thorough drying under standard conditions of 105 to110C, the mass of absorbed moisture is 0.25 kg, 10% of the sam-ples bone-dry ma
38、ss. Therefore, the regain is 10%.Table 2 lists typical regain values for materials at 24C 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. Sudden temperature ch
39、angescause 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 Requirements for Industrial Air
40、 Conditioning1(Continued )Process Dry Bulb, C rh, % Process Dry Bulb, C rh, %MATCHES PLASTICSManufacture 22 to 23 50 Manufacturing areasDrying 21 to 24 60 Thermosetting molding compounds 27 25 to 30Storage 16 to 17 50 Cellophane wrapping 24 to 27 45 to 65Water evaporates with the setting of the glue
41、. The amount of water evapo-rated is 8 to 9 kg per million matches. The actual match production rate mustbe 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 filters may be required.
42、Dust collectionand fume control are essential.PAINT APPLICATION PLYWOODLacquers: Baking 150 to 180 Hot pressing (resin) 32 60Oil paints: Paint spraying 16 to 32 80 Cold pressing 32 15 to 25The required air filtration efficiency depends on the painting process. Onfine finishes, such as car bodies, hi
43、gh-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 0.5 m/s facevelocity if spraying is performed by humans; lower air quantities can beused if robots perfo
44、rm 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 32Cementing 27 25 to 30*Dipping surgical articles 24 to 27 25 to 30*Sto
45、rage prior to manufacture 16 to 24 40 to 50*Testing laboratory 23 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 a solventrecovery system
46、for area exhaust systems.PHOTO STUDIODressing room 22 to 23 40 to 50Studio (camera room) 22 to 23 40 to 50Film darkroom 21 to 22 45 to 55 TEAPrint darkroom 21 to 22 45 to 55 Packaging 18 65Drying room 32 to 38 35 to 45Ideal moisture content is 5 to 6% for quality and mass. Low-limit moisturecontent
47、for quality is 4%.Finishing room 22 to 24 40 to 55Storage room (black and white film and paper) 22 to 24 40 to 60 TOBACCOStorage room (color film and paper) 40 to 50 40 to 50 Cigar and cigarette making 21 to 24 55 to 65*Motion picture studio 22 40 to 55 Softening 32 85 to 88The above data pertain to
48、 average conditions. In some color processes,elevated temperatures as high as 40C are used, and a higher room tempera-ture is required.Conversely, ideal storage conditions for color materials necessitate refrig-erated or deep-freeze temperatures to ensure quality and color balance whenlong storage t
49、imes 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 24 to 29 70 to 75Packing and shipping 23 to 24 65Filler tobacco casing and conditioning 24 75Filter tobacco storage and preparation 25 70Wrapper tobacco storage and conditioning 24 75*Relative humidity fairly constant with range as set by cigarette machine.Before stri
