ASHRAE OR-10-063-2010 Thermal Environment and Productivity in the Factory《工厂的热环境和生产效率》.pdf

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1、590 2010 ASHRAEABSTRACTField investigations of two different factories were carriedout in Zhenjiang and Shanghai during the cool season toanalyze the relation among indoor environment, humans, andproductivity. In particular, this study examined the effect of theworking environment and other factors

2、on thermal comfort andproductivity in factories. In this study, the mean thermalneutral temperature was 19.0 C (or 66.2 F) in the factoryduring the cool season. The results show that productivity(103.2% in Zhenjiang and 100.6% in Shanghai) does not reachits maximum when the occupants thermal sensati

3、on votes(TSV) are neutral or comfort. The highest productivity(105.1% in Zhenjiang and 104.7% in Shanghai) occurs whenthe TSV of the subjects is slightly cool. The productivity in aslightly warm state is 104.5% in Zhenjiang (103.4% in Shang-hai), which is also higher than that in a neutral state. A

4、slightlycooler or warmer environment might enhance productivitymore than in a neutral, comfortable environment. People in anenvironment with good air quality supply could easily obtainhigh productivity if the thermal environment is acceptable.Compared with other factors, maintaining good indoor airq

5、uality might be the best way to maintain higher productivityfor the factories in this survey.INTRODUCTIONDue to the large amount of time that an individual spendsindoors on the average, indoor environmental quality has asignificant effect on the health, comfort, and productivity ofworkers (ASHRAE, 2

6、005). A good thermal environmentcould help reduce occupants complaints and absenteeism.Furthermore, it contributes to occupants retention and savesmoney for agencies. Therefore, it is important to study therelationship between the parameters of thermal environmentand productivity.The elusive relatio

7、nship between thermal environmentand productivity has attracted the attention of researchers formany years. Numerous international studies and projects wereaimed at demonstrating and documenting the postulatedimpact of working space quality on occupants productivity(Srinavin and Mohamed, 2002). Howe

8、ver, the relationship hasbeen insufficiently explored (Sensharma et al., 1998;Mohamed and Srinavin, 2005; Ye et al., 2005). Laboratory andfield studies showed that many physical and chemical factorsin the working environment might have an impact on thesensation and performance of occupants, and cons

9、equently, onproductivity (Clements et al., 1999; Wargocki et al., 2000; Yeet al., 2005). There is ample evidence that an improved envi-ronment could decrease workers complaints and absentee-ism, thus indirectly enhancing productivity (Sensharma et al.,1998). People prefer to stay in a comfortable en

10、vironment.However, there is no proof that the maximum level of comfortexperiences could lead to maximum productivity (McIntyre,1980). In a real working environment, occupants comfort andproductivity depend on a number of environmental factors.There is no consensus, however, on the definition of prod

11、uc-tivity or on the specific factors in indoor environment thatinfluence productivity. Therefore, simulated office workswere often used in some studies, such as text-typing from ahard copy onto a computer screen in which spelling, grammat-ical, and logical errors had been inserted (Wargocki et al.,1

12、999; Wyon, 2004; Kosonen and Tan, 2004). As compared tooffice work, factory work is easier to measure, especiallyrepetitive work.Thermal Environment and Productivity in the FactoryXiaojiang Ye, PhD Huanxin Chen, PhD Zhiwei Lian, PhDXiaojiang Ye is an associate professor in the School of Science, Wuh

13、an Institute of Technology, Wuhan, China, and in the School of Powerand Energy, Huazhong University of Science and Technology, Wuhan, China. Huanxin Chen is a professor in the School of Power and Energy,Huazhong University of Science and Technology. Zhiwei Lian is a professor in the School of Energy

14、 and Environmental Engineering,Zhongyuan University of Technology, Henan, China. OR-10-063 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,

15、distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission. ASHRAE Transactions 591The field surveys conducted in this study were done intwo factories in China. One survey was conducted in Zhenji-ang City (located in the east of China whic

16、h is famous for itslight industry) from September 2003 to December 2003. Theother survey was done in Shanghai from December 2003 toFebruary 2004. In China, the cool season spans from Octoberto March of the next year. This study focused on the impact ofthermal comfort, indoor air quality, and some ex

17、ogenousfactors on the occupants performance or productivity. Theresearch attempted to better understand the relationshipamong productivity, workers, and indoor environment.INVESTIGATIONS AND METHODS DESCRIPTIONA total of 29 workers participated in this investigation,consisting of 18 from Zhenjiang (

18、ten females and eight males)and 11 from Shanghai (nine females and two males). Thenumber of subjects involved was similar to that used by somestudies (Bulcao et al., 2000; Engvall et al., 2005; Lee and Choi,2004). The participants were skilled workers, and all of themhave been working in factories f

19、or at least more than a year.Both physical measurements and subjective assessments wereconducted in each factory. Some indoor environmental param-eters such as indoor air temperature, black-globe temperature,air velocity, and relative humidity were measured. Thesemeasurements were conducted at repre

20、sentative points in thebuilding. The measurement instruments and heights are shownin Table 1. The instrument accuracy and measurement requirementfollowed ASHRAE Standard 55-2004 (ASHRAE, 2004) andISO 7726 (ISO, 1998). Measurements of environmental datawere taken while the subjects were completing th

21、eir question-naires. The questionnaire was used to assess the factors in theenvironment. It was divided into two parts, background infor-mation and subjective response. The background informationincluded personal information such as demography andhealth. All personal information was collected before

22、 thesurvey. The subjects were 26.44.7 years (20-45) of age,59.58.4 kg (45-81) or 131.218.5 lb of weight, and163.66.4 cm (152-175) or 64.52.5 in. of height. They werein good health. A total of 2670 returned questionnaires werecollected in the study, comprising of 1833 from Zhenjiang and837 from Shang

23、hai. The subjective response survey mainlyincluded thermal sensation, perceived indoor air quality, andpersonal comfort, among others. The scope and format ofsubjective response vote was based on some previous ques-tionnaires (Wargocki et al., 1999; Ye et al., 2004; Ye et al.,2006). The ASHRAE seven

24、-point scale of warmth was used asthe thermal sensation scale. The air quality vote scale haddescriptive equivalents ranging from very unpleasant (-3) tovery pleasant (+3). The subjects emotional state scale wasasked using a three-point scale devised by the authors; thepossible responses were “good,

25、” “common,” and “bad.” Thedetails of the scales used in this study are shown in Table 2.Metabolic rates were estimated in accordance withASHRAE Handbook (ASHRAE, 2005). The activity was lightmechanical work in Zhenjiang and light electrical industrywork in Shanghai. The metabolic rates of all the su

26、bjects wereestimated as 2.0 met (115 W/m2or 10.7 W/ft2) according tothe ASHRAE Handbook (ASHRAE, 2005). The subjectswore their ordinary clothes during the study and could freelyadjust their clothing according to the changes in indoor oroutdoor climate.The everyday output of each subject was recorded

27、 by thesupervisor to calculate his/her productivity. Each subjectsproductivity was calculated using his/her everyday output andhis/her average output during the survey, as shown in Figure 1and Equations (1) and (2). Table 1. Measurement Item, Instrument, and HeightMeasurementItemMeasurement Instrume

28、ntHeight, m (ft)Air Temperature TESTO 1100.1, 0.6, 1.1 (0.3, 2.0, 3.6)Globe TemperatureBlack-bulb (150 mm or 5.9 in.)1.1 (3.6)Air Velocity EY3-2A0.1, 0.6, 1.1 (0.3, 2.0, 3.6)HumidityDry and Wet bulb Thermometer1.1 (3.6)Table 2. Scale Used for the Evaluation of Each Factor in the SurveyScale Thermal

29、Sensation Air Quality Emotional State Comfort Level+3 Hot Very Pleasant - Very Comfortable+2 Warm Moderately Pleasant - Moderately Comfortable+1 Slightly Warm Slightly Pleasant Good Slightly Comfortable0 Neutral Neutral Common Common-1 Slightly Cool Slightly Unpleasant Bad Slightly Uncomfortable-2 C

30、ool Moderately Unpleasant - Moderately Uncomfortable-3 Cold Very Unpleasant - Very Uncomfortable 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 reproduc

31、tion, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission. 592 ASHRAE Transactions(1)(2)Where Nais the average output of the individual duringthe survey, Ndis the daily output of the individual, n is theamount of investigation of th

32、e individual, and Pdis the indi-vidual daily productivity expressed in %. A subjects dailyoutput was not at a constant rate, so his/her daily productivitywas changed. A days output of an individual that reaches his/her average level means his/her daily productivity was 100%and was selected as an ass

33、essment standard. When a subjectsdaily productivity was less than 100%, it means that his/herdaily output could not reach his/her average level, and so his/her daily productivity was low. After the survey, everysubjects daily output, daily productivity, subjective assess-ments, and environmental par

34、ameters were recorded. There-fore, the change in every subjects daily productivity andsubjective assessments followed by environmental parameterscould be easily known. The relationship between individualdaily productivity and environmental parameters could also beanalyzed. The relationship among pro

35、ductivity, thermal sensa-tion, and environmental factors was determined using statis-tical analysis (Karyono, 2000; Nicol, 1999; Heidari, 2002;Borovkov, 1998). The null hypothesis of no differencebetween conditions in terms of the performance parameterswas first tested in within-subject comparisons

36、between condi-tions using non-parametric methods such as the Friedman test(Siegel, 1956). When the data were normally distributed, anal-ysis of variance was done (Wyon, 2004). P was the probabilityvalue in this study, and 5% was taken as the level of signifi-cance. The value of 0.05 (P0.05).Most of

37、time during the survey, the subjects voted that thermalenvironment was acceptable. Therefore, it is useful to analyzethe effect of other factors on productivity when the thermalenvironment is acceptable. Figure 11 shows that indoor airquality was the top-priority factor when thermal environmentwas a

38、cceptable, with 83.2% in the high impact zone, followedby comfort level (47.1%) and thermal sensation (41.1%).Work days had the probability of 37.7%, and the emotionalstate was 32.9%. The order of priority of the factors in thiscondition could be ranked as follows: Air Quality Comfort Level Thermal

39、Sensation Workday Emotional StateDuring the survey, the occupants were also asked abouttheir preference on common adaptive actions when they expe-rienced uncomfortable thermal conditions. It was found thatmost occupants were more concerned with the air quality thanthermal comfort. More than 60% of t

40、he subjects reported thatincreasing outdoor air could make them more comfortable,while 16.7% chose changing air velocity. Therefore, to builda more comfortable or highly productive workplace, air qual-ity is one of the most significant factors that need to be consid-ered. CONCLUSIONFull-scale survey

41、s were carried out in two factories inChina to investigate the effects of thermal environment andother factors on productivity. The productivity-environmentrelationship was mainly analyzed by investigating factories inZhenjiang and Shanghai. Based on the analysis, the followingconclusions are made:1

42、. From the regression result (P0.0001), the highestproductivity reached 104.1% when the indoor tempera-ture was 24.8C (or 76.6 F) Ta. Performance in a too coldor too hot environment would decrease largely. For exam-ple, the productivity would decrease by 9% when thetemperature changes from 25.0 to 3

43、5.0 C (or 77.0 to 95.0F) Ta.2. A neutral or comfortable environment might not alwayslead to the highest productivity. A slightly cooler orslightly warmer environment might result in higherproductivity than in a neutral or comfortable environmentin the factory. The subjects productivity was the highe

44、stin a slightly cooler environment. It reached 105.1% inZhenjiang and 104.7% in Shanghai as found in the fieldwork of the study.3. Both temperature and air quality had significant effectson productivity. Moreover, temperature also had a signif-icant effect on the subjects thermal sensation, comfortl

45、evel, and emotional state (P0.05).4. People in a better air quality environment could demon-strate higher productivity when the thermal environmentwas acceptable (a more than 80% thermal environmentwas voted to be acceptable in the study). The resultshowed that maintaining good indoor air quality co

46、uld bethe optimal method to keep higher productivity in afactory. In Zhenjiang City, the productivity reached107.9% when the perceived indoor air quality was better(moderately pleasant).ACKNOWLEDGMENTSThis work was supported by National Natural ScienceFoundation of China under the contract of No.504

47、78018, andthe Cooperation Foundation of Shanghai Jiao Tong UniversityFigure 11 Influence coefficient of each factor. 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.

48、 Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission. 598 ASHRAE Transactions& Shanghai Second Medical University. It was also supportedby the National Science & Technology Pillar Program (ProjectNo. 2008BAJ

49、12B03). The authors also wished to thank Liang-jun standard unit factory (Zhenjiang) and Meishun electricindustrial factory (Shanghai) for their excellent cooperation inthis survey. And the authors also wanted to express thanks toMr Y.Chao, Mr H.Wang and Ms A.L.Lian for their translationof the paper.REFERENCESASHRAE. (2004) ANSI/ASHRAE Standard 55-2004: Ther-mal Environmental Conditions for Human Occupancy,Atlanta: American Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc.ASHRAE. (2005) ASHRAE Handbook: Fundamentals,Atlanta: American Societ