ASHRAE OR-10-021-2010 A Collection Climate Control System for an Ethnographic Storage of a Museum in North of Brazil《巴西北部博物馆民族志存储的收藏气候控制系统》.pdf

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1、196 2010 ASHRAEABSTRACTThis article presents a climate control strategy for thepreservation of collections, specially designed for andinstalled at the Amazonian ethnographic storage of theMuseu Paraense Emlio Goeldi in Belm, Brazil.Technologically simple and low cost to install, the system isrobust

2、and economical when in operation. It aims tomaintain the relative humidity below 60% to prevent thecollection from fungal and bacterial attacks while allowingthe temperature to vary with the outside climate. The systemhas maintained the designed preservation environment forthe last five years with m

3、inimum energy consumption andlow maintenance costs. The strategy has also proven itsrobustness to maintain the conservation environment evenduring extended power outages common in the region.INTRODUCTIONThe greatest threat to museum collections in hot andhumid regions is biodeterioration, especially

4、 fungal and bacte-rial attacks. (Agrawal 1993; Aranyank 1993) Since tropicalclimates are characterized by high temperature and relativehumidity which promote activities of fungi and bacteriathroughout the year, maintaining the collections in a dry envi-ronment (less than 70% RH to arrest biological

5、activity) isessential for their preservation. (Brundrett 1990) Other degra-dation mechanisms, such as mechanical damage and chemicalaging (Michalski 1993), are considered to be less importantwhen developing environmental improvement strategies forcollection preservation in these regions.An increasin

6、g number of cultural institutions have beeninstalling typical air-conditioning systems, which aredesigned for controlling the temperature for primarily humancomfort, rather than as a means of providing preservation envi-ronments for their collections. The use of a typical air-condi-tioning system, h

7、owever, can present problems for culturalinstitutions. Both the capital and the operational and mainte-nance costs are significant. It may require the installation ofthermal insulation, vapor barriers and ductwork that can resultin damage to the superstructure and/or interior of the building.And oft

8、en the installation of an air-conditioning system maynot guarantee the desired collection environment.There are serious needs for developing climate controlstrategies that produce suitable preservation environmentsthat are economical, robust, technologically simple, andrequire minimal structural mod

9、ification. Climate control strat-egies based on the use of ventilation, conservation heating, anddehumidification or any combination of those, which are alter-natives to a typical or traditional air-condition based approach,have been successfully tested in cultural institutions intemperate and humid

10、 climates. (Kerschner 1992; Padfield andJersen 1990; Staniforth et al. 1994; Maekawa and Toledo2001, 2002; Valentn et al. 1998) These alternative strategieswill provide necessary beneficial alternatives to collectionmanagers and conservators in tropical and sub-tropicalclimates, if they can be succe

11、ssfully tested in the region.The Museu Paraense Emlio Goeldi (MPEG), located ina northern Brazilian city of Belm and the oldest scientificinstitution still active in the Amazon region and the secondoldest natural history museum in Brazil, has collections ofboth historical and scientific significance

12、 regarding the knowl-edge of flora and fauna, the physical environment, and socialA Collection Climate Control System for an Ethnographic Storage of a Museum in North of BrazilShin Maekawa, PhD, PE Franciza Toledo, PhDMember ASHRAEShin Maekawa is a senior scientist in charge of the Environmental Stu

13、dies Laboratory of the Getty Conservation Institute, Los Angeles, CA.Franciza Toledo is a private lecturer at the Universidade Federal de Pernambuco, Brazil.OR-10-021 2010, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transacti

14、ons 2010, Vol. 116, Part 1. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission. ASHRAE Transactions 197groups that currently dwell or have dwelled in the northernregions of Brazil. Th

15、e Amazonian ethnographic collectionconsists of about 15,000 objects from different ethnic groups:objects used in agriculture, fishing and hunting, food process-ing, ceremonies and celebrations. Classified according toregion and tribe, they are mostly basketry, instruments, andornaments, that are mad

16、e from plant fibers, woods, seeds andbird feathers.The climate of Belm is characterized as hot and humid,with annual average air temperature values of 78.4F (25.8C)in 1931-1960 and 78.8F (26C) in 1961-1990, relative hu-midity values of 86% in 1931-1960 and 86.5% in 1961-1990.The relative humidity ca

17、n reach 100% during the rainy season,but the maximum air temperature never gets higher than90.5F (32.5C) in the dry season, the minimum value being72.5F (22.5C) in the rainy season (www.inmet.gov.br). Therainy season is from December to May, and the dry season isfrom June to November. The annual rai

18、n accumulation was109.25 in. (2775 mm) in 1931-1960 and 113.78 in. (2890 mm)in 1961-1990. Because of the high daily evaporation, it isworth noting that it rains on a daily basis in Belm, at the endof the day, with monthly values falling between 1.97 and5.9 in. (50 and 150 mm) in the dry period. Sola

19、r radiationattains its maximum in July and August (about 270 h of sunincidence), and its minimum in February and March (about100 h). Evaporation is also high in the dry period (about3.15 in. (80 mm) in July and August).The majority of MPEGs storage environments are main-tained by dual sets of severa

20、l room (window-mount) air-conditioning units which are utilized in day and night shifts forextended maintenance-free operation of continuous climatecontrol. However, these units are designed to produce lowtemperatures for human comfort, and these are not to maintaina stable preservation environment

21、for collections. Further-more, we can often see a large growth of black mold on thebuildings outside walls due to dew condensation resultingfrom a combination of poorly insulated walls and low inertiatemperatures. Prior to the climate improvement project, theAmazonian ethnographic collection occupie

22、d two storagerooms at the Rocinha campus, the MPEGs headquarters nearthe city center of Belm. These rooms were over-packed,poorly furnished, and climatically unstable due to intermittentoperation of room air conditioners, resulting in daily climateranges of 81.5 to 90.5F (27.5 to 32.5C) and 45 to 70

23、% RHas shown in Figure 1. There were also drawers full of naph-thalene for protection against insects.Another issue is that air-conditioning units consume largeamounts of power. Table 1 shows the monthly energy con-sumption at the MPEG in 2002 produced from its monthlyelectricity bills. Including th

24、e daytime use of room air-conditioning units in individual office spaces, the museumspends about 70% of its budget on electricity. Since energyconsumption of a particular storage facility cannot be isolatedfrom the museums energy bill, we estimated the energy costof the old Amazonian ethnographic st

25、orage based on equip-ment installed in the facility as shown in Table 2. With thenationwide energy crisis in 2001, the Brazilian governmentmandated its facilities to reduce energy consumption by 30%by 2007. Therefore, the museum has been anxious to reduce itsenergy use.In addition, frequent and exte

26、nded power outages are verycommon in the region and are another reason for fungal andinsect outbreak, despite heavy and broad use of insecticidesand fungicides. The museum was therefore searching for aninnovative climate control approach that would be low-cost forboth installation and operation, tec

27、hnologically robust, andcapable of maintaining a stable conservation environment,even in a period of an extended power outage.Table 1. Daily and Monthly Energy Consumption at the MPEG in 2002MonthDaily Consump-tion (kWh)Monthly Consump-tion (kWh)Total Cost (R$)January 5,675 175,940 36,628.20February

28、 6,184 173,162 39,697.27March 4,831 149,746 39,789.05April 5,685 170,551 43,926.38May 6,156 190,850 46,952.25June 6,246 187,392 50,123.66July 6,110 189,436 48,703.51August 6,037 187,166 58,214.48September 6,602 198,088 55,814.51October 5,092 157,857 45,652.57November 5,855 175,677 42,762.91December

29、5,064 157,007 37,929.16Total 69,537 2,112,872 546,193.95Source: Electricity bills. R$ is Brazilian Currency, R$1 = $0.475$ U.S. as of May 8,2009Figure 1 Temperature and relative humidity in the oldAmazonian ethnographic storage at the MPEG in2002. 2010, American Society of Heating, Refrigerating and

30、 Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions 2010, Vol. 116, Part 1. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission. 198 ASHRAE Transaction

31、sNEW STORAGE FACILITYIn 2003, the MPEG gained a new storage space for theAmazonian ethnographic collection at its research campus atthe edge of the city. It is located in a typical single-storycontemporary urban building and consists of three rooms usedfor: (1) reception, quarantine and conservation

32、 treatments; (2)inventory and study of collections; and (3) the storage itself.The storage area measures 49 ft-3 in. 59 ft (15 m 18 m (270m2), has a cement slab floor, a concrete slab ceiling of 9 ft-10in. (3 m) high, and the walls are made of fired hollow bricksfinished with cement plaster and whit

33、e water-based paint. Theroof is of corrugated metal sheets in two chutes, with a centralair gap for passive ventilation of the attic space, with longeaves and a suitable surrounding drainage system.Conceptual Design for Climate ControlThe proposed climate control system for the new storagearea consi

34、sted of sets of supply and exhaust ventilators andseveral portable mechanical dehumidifiers, and was to operatebased on the output of relative humidity sensors located bothinside and outside the buildings. The system was to operateonly when the relative humidity rose higher than 70%thethreshold for

35、microbial activities. The ventilators were tooperate when the outside relative humidity was lower than thevalue to remove moisture, and the dehumidifiers were to acti-vate when the outside relative humidity was higher than 70%.Therefore, the ventilators could not be used. It was decided touse mechan

36、ical dehumidifiers instead of heaters to reduce therise of already high temperature and conserve energy. Theapproach would provide relative humidity control to protectthe collection from the threat of fungi and bacteria whileallowing the temperature to vary, since chemical aging andmechanical damage

37、s were not considered to be threatening.Engineering Design of Climate Control SystemThe conceptual design of the climate system wasforwarded to a local architect and HVAC company for detaildesign, equipment selection, and installation under theauthors supervision. Figure 2 shows locations of various

38、HVAC equipment for the storage. The system consisted of twolarge 953 cfm (1620 m3/h) each centrifugal-type supply fans,four 424 cfm (723 m3/h) each axial-type exhaust fans, sixoscillating fans, four portable mechanical dehumidifiers177 cfm (300 m3/h), 1331 Btu/h (390 W) each and twohumidistats. The

39、supply air ventilators were placed outside thebuilding, bringing filtered outside air through two centrallylocated ducts mounted under the ceiling, and distributing airthrough five diffusers on each side. Each supply fan had aninsect net and double banks of G3-type particle filters. Theventing air,

40、after flowing through the shelves and drawers, wascollected near the floor through two ducts with five returnopenings each, and along two walls which were parallel to thesupply air ducts, and ducted to the exhaust fans located in wallcavities. Gravitational-type shutters were installed on theirexhau

41、sts to prevent the infiltration of the outside air andinsects. Four portable dehumidifiers connected to permanentdrains were located near four corners of the storage room.Three oscillating fans mounted near the ceiling on sidewallsoperated with the dehumidifiers for mixing the room air.Another three

42、 oscillating fans, independently operable, wereinstalled on center columns to provide comfort for staffmembers and researchers. Two humidistats, with one relativehumidity sensor inside the storage and the other outside thebuilding, controlled the operation of ventilators, fans, anddehumidifiers. The

43、 climate system operated only when theinterior relative humidity exceeded 70%, and deactivated oncethe relative humidity was reduced to equal or less than 60%.The ventilators (supply and exhaust ventilators) were operatedsimultaneously when the outside relative humidity was equalor less than 70%. If

44、 the outside relative humidity rose higherthan 70%, wall fans and mechanical dehumidifiers were acti-vated simultaneously, while ventilators were turned off. Costsof the detailed design, the equipment, and labor for the instal-lation were approximately R$4.33/ft3(R$153/m3) in 2003,less than one-fift

45、h of a typical climate control system whichcontrolled both temperature and relative humidity.Building Envelope ModificationsFor the installation of the climate control system, somearchitectural modifications were made on the building enve-lope of the new storage space to improve its air tightness. T

46、hemodifications included the elimination of a large steel doordirectly leading to the outside and wall openings for air-condi-tioners. Some of the wall openings were converted towindows. The ceiling was insulated with 4 in. (0.10 m) thickfiberglass panels to minimize the heat transmission from theat

47、tic. An area surrounding the storage was paved for improveddrainage around the building. Two fireproof metal doors wereinstalled: one at the entrance to access the storage, and theother to access the conservation lab. A vestibule area wascreated just outside glass entrance doors into the storagesurr

48、ounded by the two metal doors and a brick internal wall.This area provided a transition space between the storage andTable 2. Estimated Monthly Energy Consumption in the Old Ethnographic StorageNo. of UnitsEquipment,Btu RatingWatts Hours DaysConsumption (kWh)1 Air cond. 30,000 3900 12 22 1029.601 Ai

49、r cond. 30,000 3900 12 22 1029.601 Air cond. 30,000 3900 12 22 1029.601 Air cond. 14,000 2070 12 22 546.481 Air cond. 14,000 2070 12 22 546.4822 Fluorescent light 40W 880 08 22 154.88Total 4336.64 2010, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions 2010, Vol. 116, Part 1. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission. ASHRAE Transactions 199non-stor