1、23.1CHAPTER 23REFRIGERATED-FACILITY DESIGNInitial Building Considerations. 23.1Refrigeration Systems 23.7Insulation Techniques . 23.12Applying Insulation . 23.13Other Considerations 23.15EFRIGERATED facilities are any buildings or sections of aR building that achieve controlled storage conditions us
2、ingrefrigeration. Two basic storage facilities are (1) coolers that protectcommodities at temperatures usually above 0C and (2) low-temperature rooms (freezers) operating under 0C to prevent spoil-age or to maintain or extend product life.The conditions within a closed refrigerated chamber must bema
3、intained to preserve the stored product. This refers particularly toseasonal, shelf life, and long-term storage. Specific items for con-sideration includeUniform temperaturesLength of airflow pathway and impingement on stored productEffect of relative humidityEffect of air movement on employeesContr
4、olled ventilation, if necessaryProduct entering temperatureExpected duration of storageRequired product outlet temperatureTraffic in and out of storage areaIn the United States, the U.S. Public Health Service Food andDrug Administration developed the Food Code (FDA 1997), whichprovides model require
5、ments for safeguarding public health andensuring that food is unadulterated. The code is a guide for estab-lishing standards for all phases of handling refrigerated foods. Ittreats receiving, handling, storing, and transporting refrigeratedfoods and calls for sanitary as well as temperature requirem
6、ents.These standards must be recognized in the design and operation ofrefrigerated storage facilities.Regulations of the Occupational Safety and Health Adminis-tration (OSHA), Environmental Protection Agency (EPA), U.S. De-partment of Agriculture (USDA), and other standards must also beincorporated
7、in warehouse facility and procedures.Refrigerated facilities may be operated for or by a private com-pany for storage or warehousing of their own products, as a publicfacility where storage services are offered to many concerns, orboth. Important locations for refrigerated facilities, public or pri-
8、vate, are (1) point of processing, (2) intermediate points for gen-eral or long-term storage, and (3) final distributor or distributionpoint.The five categories for the classification of refrigerated storagefor preservation of food quality areControlled atmosphere for long-term fruit and vegetable s
9、torageCoolers at temperatures of 0C and aboveHigh-temperature freezers at 2 to 3CLow-temperature storage rooms for general frozen products, usu-ally maintained at 20 to 29CLow-temperature storages at 20 to 29C, with a surplus ofrefrigeration for freezing products received at above 18CNote that, beca
10、use of ongoing research, the trend is toward lowertemperatures for frozen foods. Refer to Chapters 25 and 26 of the2009 ASHRAE HandbookFundamentals and Chapter 21 of thisvolume for further information.INITIAL BUILDING CONSIDERATIONSLocationPrivate refrigerated space is usually adjacent to or in the
11、samebuilding with the owners other operations.Public space should be located to serve a producing area, a transitstorage point, a large consuming area, or various combinations ofthese to develop a good average occupancy. It should also have thefollowing:Convenient location for producers, shippers, a
12、nd distributors,considering the present tendency toward decentralization andavoidance of congested areasGood railroad switching facilities and service with minimumswitching charges from all trunk lines to plant tracks if a railheadis necessary to operate the business profitablyEasy access from main
13、highway truck routes as well as localtrucking, but avoiding location on congested streetsAmple land for trucks, truck movement, and plant utility spaceplus future expansionLocation with a reasonable land costAdequate power and water supplyProvisions for surface, waste, and sanitary water disposalCon
14、sideration of zoning limitations and fire protectionLocation away from residential areas, where noise of outsideoperating equipment (i.e., fans and engine-driven equipment onrefrigerated vehicles) would be objectionableExternal appearance that is not objectionable to the communityMinimal tax and ins
15、urance burdenPlant securityFavorable undersoil bearing conditions and good surface drainagePlants are often located away from congested areas or even out-side city limits where the cost of increased trucking distance is off-set by better plant layout possibilities, a better road network, betteror lo
16、wer-priced labor supply, or other economies of operation.Configuration and Size DeterminationBuilding configuration and size of a cold-storage facility aredetermined by the following factors:Is receipt and shipment of goods to be primarily by rail or bytruck? Shipping practices affect the platform a
17、reas and internaltraffic pattern.What relative percentages of merchandise are for cooler and forfreezer storage? Products requiring specially controlled condi-tions, such as fresh fruits and vegetables, may justify or demandseveral individual rooms. Seafood, butter, and nuts also requirespecial trea
18、tment. Where overall occupancy may be reducedThe preparation of this chapter is assigned to TC 10.5, Refrigerated Distri-bution and Storage Facilities.23.2 2010 ASHRAE HandbookRefrigeration (SI)because of seasonal conditions, consider providing multiple-usespaces.What percentage is anticipated for l
19、ong-term storage? Productsthat are stored long term can usually be stacked more densely.Will the product be primarily in small or large lots? The drive-through rack system or a combination of pallet racks and a mez-zanine have proved effective in achieving efficient operation andeffective use of spa
20、ce. Mobile or moving rack systems are alsovalid options.How will the product be palletized? Dense products such as meat,tinned fruit, drums of concentrate, and cases of canned goods canbe stacked very efficiently. Palletized containers and special pal-let baskets or boxes effectively hold meat, fish
21、, and other looseproducts. The slip sheet system, which requires no pallets, elimi-nates the waste space of the pallet and can be used effectively forsome products. Pallet stacking racks make it feasible to use thefull height of the storage and palletize any closed or boxed mer-chandise.Will rental
22、space be provided for tenants? Rental space usuallyrequires special personnel and office facilities. An isolated areafor tenant operations is also desirable. These areas are usuallyleased on a unit area basis, and plans are worked into the mainbuilding layout.The owner of a prospective refrigerated
23、facility may want toobtain advice from specialists in product storage, handling, andmovement systems.Stacking ArrangementTypically, the height of refrigerated spaces is at least 8.5 to 10.5 mor more clear space between the floor and structural steel to allowforklift operation. Pallet rack systems us
24、e the greater height. Thepractical height for stacking pallets without racks is 4.5 to 5.5 m.Clear space above the pallet stacks is used for air units, air distribu-tion, lighting, and sprinkler lines. Generally, 2 to 3 m minimumclear height is required from top of product to bottom of supportstruct
25、ure to ensure there is no interference with drain pan and drainlines of air units. Greater clear heights are usually required if auto-mated or mechanized equipment is used. Overhead space is inex-pensive, and because the refrigeration requirement for extra heightis not significant in the overall pla
26、nt cost, a minimum of 6 m clearheight is desirable. Greater heights are valuable if automated ormechanized material handling equipment is contemplated. Theeffect of high stacking arrangements on insurance rates should beinvestigated.Floor area in a facility where diverse merchandise is to be storedc
27、an be calculated on the basis of 130 to 160 kg per gross cubic metre,to allow about 40% for aisles and space above the pallet stacks. Inspecial-purpose or production facilities, products can be stacked withless aisle and open space, with an allowance factor of about 20%.Building DesignMost refrigera
28、ted facilities are single-story structures. Small col-umns on wide centers allow palletized storage with minimal lostspace. This type of building usually provides additional highwaytruck unloading space. The following characteristics of single-storydesign must be considered: (1) horizontal traffic d
29、istances, which tosome extent offset the vertical travel required in a multistory build-ing; (2) difficulty of using the stacking height with many commod-ities or with small-lot storage and movement of goods; (3) necessityfor treatment of the floor below freezers to give economical protec-tion again
30、st possible ground heaving; and (4) high land cost forbuilding capacity. A one-story facility with moderate or low stack-ing heights has a high cost per unit area because of the high ratio ofconstruction costs and added land cost to product storage capacity.However, first cost and operating cost are
31、 usually lower than for amultistory facility.One-Story ConfigurationFigure 1 shows the layout of a one-story 23C freezer that com-plies with current practices. The following essential items and func-tions are considered:Refrigeration machinery roomRefrigerated shipping docks with seal-cushion closur
32、es on thedoorsAutomatic doorsBatten doors or strip curtainsLow-temperature storage held at 23C or lowerPallet-rack systems to facilitate handling of small lots and to com-ply with first-in, first-out inventory, which is required for someproductsBlast freezer or separate sharp freezer room for isolat
33、ion of prod-ucts being frozenCooler or convertible spaceSpace for brokerage officesSpace for empty pallet storage and repairSpace for shop and battery chargingAutomatic sprinklers in accordance with National Fire ProtectionAssociation (NFPA) regulationsTrucker/employee break areaValve stations for u
34、nderfloor heatingEvaporative condenser(s) locationOther areas that must be in a complete operable facility areElectrical areaShipping officeAdministration officePersonnel welfare facilitiesA modified one-story design is sometimes used to reduce hori-zontal traffic distances and land costs. An altern
35、ative is to locatenonproductive services (including offices and the machinery room)on a second-floor level, usually over the truck platform work area,to allow full use of the ground floor for production work and stor-age. However, potential vibration of the second floor from equip-ment below must be
36、 considered.One-story design or modification thereof gives the maximumcapacity per unit of investment with a minimum overall operatingFig. 1 Typical Plan for One-Story Refrigerated FacilityFig. 1 Typical Plan for One-Story Refrigerated FacilityRefrigerated-Facility Design 23.3expense, including amor
37、tization, refrigeration, and labor. Mechani-zation must be considered, as well. In areas where land availabilityor cost is a concern, a high-rise refrigerated storage building may bea viable option.Designs that provide minimum overall costs restrict office facil-ities and utility areas to a minimum.
38、 They also include ample dockarea to ensure efficiency in loading and unloading merchandise.Shipping and Receiving DocksTemperature control regulations for all steps of product handlinghave led to designing the trucking dock as a refrigerated anteroomto the cold storage area. Dock refrigeration is a
39、n absolute necessityin humid and warm climates. Typically, loading and unloadingtransport vehicles is handled by separate work crews. One crewmoves the product in and out of the vehicles, and a warehouse crewmoves the product in and out of the refrigerated storage. This pro-cedure may allow merchand
40、ise to accumulate on the shipping dock.Maintaining the dock at 2 to 7C offers the following advantages:Refrigeration load in the low-temperature storage area, whereenergy demand per unit capacity of refrigeration is higher, isreduced.Less ice or frost forms in the low-temperature storage becauseless
41、 humid and warm air infiltrates the area.Refrigerated products held on the dock maintain a more favorabletemperature, thus maintaining product quality.Packaging remains in good condition because it stays drier. Facil-ity personnel are more comfortable because temperature differ-ences are smaller.Les
42、s maintenance on forklifts and other equipment is requiredbecause condensation is reduced.Need for anterooms or vestibules to the freezer space is reduced oreliminated.Floor areas stay drier, particularly in front of freeze door areas.This assists in housekeeping and improves safety.Utility SpaceSpa
43、ce for a general office, locker room, and machinery room isneeded. A superintendents office and a warehouse records officeshould be located near the center of operations, and a checkersoffice should be in view of the dock and traffic arrangement. Rentedspace should be isolated from warehouse operati
44、ons.The machinery room should include ample space for refrigera-tion equipment and maintenance, adequate ventilation, standbycapacity for emergency ventilation, and adequate segregation fromother areas. Separate exits are required by most building codes. Amaintenance shop and space for parking, char
45、ging, and servicingwarehouse equipment should be located adjacent to the machineryroom. Electrically operated material-handling equipment is used toeliminate inherent safety hazards of combustion-type equipment.Battery-charging areas should be designed with high roofs and mustbe ventilated, because
46、of the potential for combustible fumes fromcharging.Specialized Storage FacilitiesMaterial handling methods and storage requirements often dic-tate design of specialized storage facilities. Automated materialhandling in the storage, particularly for high stack piling, may beintegral to the structure
47、 or require special structural treatments.Controlled-atmosphere and minimal-air-circulation rooms requirespecial building designs and mechanical equipment to achievedesign requirements. Drive-in and/or drive-through rack systemscan improve product inventory control and can be used in combi-nation wi
48、th stacker cranes, narrow-aisle high stacker cranes, andautomatic conveyors. Mobile racking systems may be consideredwhere space is at a premium.In general, specialized storage facilities may be classified asfollows:Public refrigerated facility with several chambers designed tohandle all commodities
49、. Storage temperatures range from 1.5 to15C (with humidity control) and to 29C (without humiditycontrol).Refrigerated facility area for case and break-up distribution, auto-mated to varying degrees. The area may incorporate racks withpallet spaces to facilitate distribution.Facility designed for a processing operation with bulk storage forfrozen ingredients and rack storage for palletized outshipment ofprocessed merchandise. A common, efficient adaptation is toadjoin the refrigerated facility to the processing plant.Public refrigerated facility serving several produ
