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Human Thermal Sensation and Comfort in Transient and Non-Uniform Thermal Environments

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Human Thermal Sensation and Comfort in Transient and Non-Uniform Thermal Environments UC Berkeley Indoor Environmental Quality (IEQ) Title Human thermal sensation and comfort in transient and non-uniform thermal environments Permalink https://escholarship.org/uc/item/11m0n1wt Author Zhang, H. Publication Date 2003-09-01 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Human Thermal Sensation and Comfort in Transient and Non-Uniform Thermal Environments by Hui Zhang B.E. (Tsinghua University) 1983 M.E. (Tsinghua University) 1986 A dissertation submitted in partial satisfaction of the requirement for the degree of Doctor of Philosophy in Architecture in the GRADUATE DIVISION of the UNIVERSITY OF CALIFORNIA, BERKELEY Committee in charge: Professor Edward A. Arens, Chair Professor Gail S. Brager Professor Boris Rubinsky Specialist Charlie Huizenga Fall 2003 Title Human Thermal Sensation and Comfort in Transient and Non-Uniform Thermal Environments Ó 2003 by Hui Zhang Abstract Human Thermal Sensation and Comfort in Transient and Non-Uniform Thermal Environments by Hui Zhang Doctor of Philosophy in Architecture University of California, Berkeley Professor Edward A. Arens, Chair Most existing thermal comfort models are only applicable only in uniform, steady-state thermal environments. This thesis presents results from 109 human subject tests that were performed under non-uniform and transient conditions in the UC Berkeley Controlled Environmental Chamber. In these tests, local body surfaces of the subjects were independently heated or cooled while the rest of the body was exposed to a warm, neutral or cool environment. Skin temperatures, core temperature, thermal sensation and comfort responses were collected at one- to three-minute intervals. Based on these tests, we have developed predictive models of local and overall thermal sensation and comfort: q Local thermal sensation for 19 body parts q Local thermal comfort model for 19 body parts q Overall sensation model q Overall comfort model 1 A separate set of tests was carried out in an automobile in a climate-controlled wind tunnel at the Delphi Harrison facility in Lockport, NY. These tests simulated conditions found in vehicles during both hot and cold weather. The subjects’ body temperatures, thermal sensation and thermal comfort were measured similarly to those in the UCB chamber tests. The results of the Delphi tests were primarily used for model validation. The validation results show that the models predicted the actual sensation and comfort votes well. The models will be useful for designing and evaluating non-uniform and transient environments in buildings, vehicles, and outdoors. 2 TABLE OF CONTENTS 1. Introduction ................................................................................................................................. 1 2. Background ................................................................................................................................. 3 2.1 Physical basis of thermal sensation............................................................................. 5 2.1.1 Thermoreceptors................................................................................................... 5 2.1.2 Hypothalamus thermoregulation ......................................................................... 8 2.2 Models of thermal sensation in stable asymmetrical conditions ............................. 10 2.2.1 Weighting factor approach................................................................................. 10 2.2.2 EHT and Piste..................................................................................................... 14 2.3 Models of dynamic thermal sensation ...................................................................... 16 2.4 Sensation and comfort ............................................................................................... 22 2.5 Need for human subject tests .................................................................................... 25 3. Objectives .................................................................................................................................. 27 4. Methods ..................................................................................................................................... 29 4.1 General description of the experiment...................................................................... 29 4.2 Experimental Facility ................................................................................................ 30 4.2.1 Controlled Environmental Chamber.................................................................. 30 4.2.2 Local warm- and cold-air supplies .................................................................... 31 4.2.3 Pre-conditioning bath ......................................................................................... 32 4.2.4 Air sleeves for local cooling and heating.......................................................... 34 4.2.4.1 General air-sleeve design ........................................................................... 36 4.2.4.2 Leotard ........................................................................................................ 37 4.2.4.3 Air-sleeve design for different body parts................................................. 38 4.3 Measurement.............................................................................................................. 45 4.3.1 Skin Temperature Measurement........................................................................ 45 4.3.1.1 Skin Temperature Measurement Sites....................................................... 45 4.3.1.2 Thermocouples............................................................................................ 48 4.3.1.2.1 Calibration of the thermocouples ....................................................... 49 4.3.1.2.2 Data acquisition................................................................................... 50 4.3.2 Core temperature measurement ......................................................................... 50 4.3.2.1 Wireless Sensor Pill.................................................................................... 50 4.3.2.2 Discussion of core measurement methods ................................................ 52 4.3.3 Thermal sensation and comfort ......................................................................... 53 4.3.3.1 Seven-point sensation scale and Bedford’s comfort scale........................ 53 4.3.3.2 Sensation and comfort scales used in our tests ......................................... 55 4.4 Test description.......................................................................................................... 58 4.4.1 Test procedure .................................................................................................... 58 4.4.2 Types of tests...................................................................................................... 59 i 4.4.2.1 Single body part cooling and heating test.................................................. 59 4.4.2.2 Multiple segment cooling and heating test................................................ 62 4.4.2.3 Whole-body step-change tests ................................................................... 63 4.4.2.4 Neutral-condition tests ............................................................................... 64 4.4.2.5 Taking Infrared video images .................................................................... 65 4.4.2.6 Delphi Wind Tunnel tests........................................................................... 66 4.5 Human subjects.......................................................................................................... 72 4.5.1 UCB subjects ...................................................................................................... 72 4.5.2 Body composition information.......................................................................... 73 4.5.3 Subjects’ clothing............................................................................................... 74 4.5.4 Metabolic level of subjects ................................................................................ 75 4.5.5 Delphi subjects ................................................................................................... 75 5. Test Results, Physiological and Subjective Responses........................................................... 77 5.1 Introduction................................................................................................................ 77 5.2 Stable/uniform environments .................................................................................... 79 5.2.1 Neutral-conditions tests...................................................................................... 79 5.2.1.1 Skin temperature set points ........................................................................ 80 5.2.1.1.1 Experimental results ........................................................................... 80 5.2.1.1.2 Comparison with values in the literature ........................................... 82 5.2.1.2 Sensation and comfort in neutral conditions ............................................. 84 5.2.1.3 Responses over time ................................................................................... 88 5.2.2 Cold-condition tests............................................................................................ 91 5.2.2.1 Skin temperature distribution....................................................................
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