Showing papers on "Thermal comfort published in 1993"

Localized comfort control with a desktop task conditioning system : laboratory and field measurements

Abstract: Author(s): Bauman, Fred; Zhang, H.; Arens, Edward A; Benton, C. | Abstract: This paper reports the results of recently completed laboratory and field measurements investigating the thermal performance of an occupant-controlled desktop task conditioning system. The laboratory experiments were performed in a controlled environment chamber configured to resemble a modern office space with modular workstation furniture and partitions. Velocity and temperature distributions were measured throughout the test chamber for a range of test conditions to investigate the effects of supply volume and direction, supply outlet size, and heat load levels (both uniform and nonuniform) in the space. Comfort model predictions are presented to describe the degree of environmental control and range of occupant comfort levels produced in the workstations. Individual desktop units in side-by-side workstations having significantly different heat load levels could be adjusted to maintain close to comfortable conditions, demonstrating localized comfort control.The field study was performed in a small demonstration office containing two permanent data acquisition systems capable of monitoring in detail the thermal and energy performance of the office, including four installed desktop task conditioning units. Portable measurement methods were also used to assess the thermal comfort of the workers occupying the office. Initial results from the field study demonstrate the occupant response and use patterns of the desktop system, typical energy use pattrns, and the effect of the desktop system on local air velocities and thermal comfort within the workstations.

A Comparison of Methods for Assessing Thermal Sensation and Acceptability in the Field

Abstract: Proceedings. Thermal Comfort: Past, Present and Future N. Oseland, ed., Building Research Establishment, Watford, United Kingdom, July 1993. A comparison of methods for assessing thermal sensation and acceptability in the field ' Gail S Brager, Marc E Fountain, Charles C Benton, Edward A Arens and Fred S Bauman Building Science Group, University of California, Berkeley, USA. Abstract Architects, engineers, and facility managers are eager to know how to design and operate buildings to create acceptable (and perhaps even pleasurable) thermal environments. For guidance, they look to thermal comfort standards, which have been developed based on knowledge gained primarily from laboratory experiments. Laboratory studies have provided us with a wealth of knowledge in the areas of thermophysiology, heat exchange, and subjective response, and greatly contribute to the foundation of our understanding about thermal comfort. Field studies of thermal comfort are equally important, and frequently ask different questions. For example, What thermal environments currently exist in buildings, and to what extent do they compare to people’s responses in the laboratory? How do the building occupants’ assessment of ”acceptabilityq compare with what’s prescribed by the standards? What do we need to know to successfully apply laboratory-based models to the field, and what additional factors occur in buildings that we either don’t know enough about, or are not accounting for in the models? In this paper, we use data from ASHRAE 462—RP and other field studies to examine methods for predicting thermal sensation and assessing acceptability in the field. Results show the importance of accounting for the insulation value of the chair, using new clo values given in ASHRAE Standard 55-92 as opposed to those in ASHRAE Standard 55 -81 , and using a more realistic estimation of net value for office activity. By incorporating new values for these factors in the analysis, the laboratory based PMV more closely matches measured mean thermal sensation in the field. Beyond predictions of thermal sensation, we also examine traditional methods used in standards for assessing the acceptability of the thermal environment. These include the commonly used assumption of equating specific thermal sensations with comfort and satisfaction, and the assumption that the optimum temperature corresponds to a neutral thermal sensation. Using data from several field studies, we compare people’s responses to different scales to examine the validity of this approach and the potential influence of seasons. Some effects noted are that a significant number of people voting outside the 3 central categories of the thermal sensation scale find these to be comfortable; preferences for non- neutral thermal sensations are common and may change with seasons; and different measures of dissatisfaction produce widely different assessments of the acceptability of a given environment. 17

Air movement and thermal comfort

Abstract: and Airmovement thermalcomfort on information ThenewASHRAE Standard provides comfort indoor air velocities occupant appropriate for By Marc E. Fountain and Mward A. Arens, Ph.D. MemberASHRAE Associate MemberASHRAE heat of Many, notmost, if commercial trolsthe release metabolic by design innovations, buildings. ecent HVAC primarily by skin the of builtsince middle this regulating temperaturg concerns buildings conservation energy and at skin supply sweadng to use systems varying blood dataon century air distribution and newlaboratory heated and/or cooled to occu- theskinsurface. air have brought substantial deliver drafrs heat at Convective transfer ihe skin lEvels to of attention theissue acceptable ol piedspaces. with surface and temperature local Accordingly', ASHRAEand other varies in air movement officeenvironments. Exten- across skinsurface the have and air motion sunduds desirable organizations produced mayprovide Air movement have shor.r'n that studies for this but also guidelines distributing air.Included sivelaboratory conditions, it may cooling u,alm in vote such documents specifics as: thermalsensation (an important are cool in these the increase riskof unacceptably thermal comfort) is percentage method measuring for of of may Detectable movement be volume airperunittime, air drafts. in related skintemperature cool to of perceived the occupants provid- outdoor andtype location duct closely ail and as by conditions. warmand In andcomfonable to ing freshness pleasantness the outlets. and warm-humid moisture the on conditions, In general, design recommendations as be air, breathing ya it mayalso perceived effect thermal on sensa- cfm have favored specifying deiivered per skinhasa strong annoying. after mechan- than tion,particularly sweating foot space a air has Clearlll specific speed many square of occupied rather triggered. have been airvelocity achieving for thermal isms possible physiological subjective con- specifying and Howwer, desired the end-product froma pleasant comfon. These sequences. range is to sense of sense coolness anunpleasant of oi HVACsystems not cfmper square About theauthon interior air move- or dnft, depending theair emperaturg foot,a cooledbuilding on and it health humidit v, cloth- mentperse; is thecomfort, radiant ternpeftlturg mean at MarcE. Founsinisa PhDcandidate the of (UCB). occupants. ing, metabolic and air movement satisfaction building rate Uniwnity of Califomia-Berkelry preference theoccupant. from Beyond special such laborato cases as his Hereteived BA in physics UCB. of member Fountain a corrsponding is of rooms, in ASH- riesandclean efforts HVACare the Since turnof thecentury, and ASHRAE 1.1(Ph.vsiology Human TC directed producing at thermal have primarily comfon rerarchers RAEandthermal active ther- and been in and that acceptable Environment) has worked define to levels air movement comfort airquality are of since induding malcomfon research 1986 possible for breathing. focus this isthe The anicle of thatareaccepuble thewidest to t s c o n t r i b u t i o n o e S H R A ER e s e a r c h (created group indiriduals b1' within evolving influence theairmovement of oi an Projects RP{62andRP-702 system) thermal on comfort. and architectural serting, to incorporate an HVAC in A. Edu'ard Arensis a professor the Air velocity oneof sixmainvaria- is these results anindoor into elvironmental at Depanment fuchitecture theUniver- of The bles affeaing human thermal comfort. standard. and physical variables sityof California-Berkeley direoor three Thisanicleoutlines current the state otherfiveinclude Design of the Centerfor Environmental mean temperature to (airtemperature radiant Referenceis made also of thisdiscussion. his Raearch. received PhDin archi- He humidity) tr+o and behavionlly investigating effectof air andrelatirre the research fromthe University tectural science of (metabolic and variables rate and movement thermal on comfort the regulated Edinburgh hisundergraduate and and insulation). dwelopment air velocity of limitsin the clothing manen from degrees lhleUniversiry sys- In humans, thermoregulatory the comfort latesr ASHRAE thermal standard. Sundards is serving the SPC-i5-92R on temisresponsible maintaining heu the for hoia Committee, isa conespmding and Whyisair velocity important? a of balance thebodyusing core ol setpoint member TC2.1anda past+hairman of of (37 C) withintheconstrainu the of to design TC 25 (Air FlowAroundBuildines). HVACengineers systems 98.6 F given This con- move and air energy ventilating through sixvariables above system H 1 . 1 R I E J o u n a l A u g u s rI 9 9 3

A bioclimatic design methodology for urban outdoor spaces

Abstract: The development of a bioclimatic urban design methodology is described. The cluster thermal time constant (CTTC) model for predicting street-level urban air temperature variations is coupled with the wind-profile power law and the index of thermal stress (ITS.) for human comfort. TheCTTC model and the power law produce the diurnal air temperature and wind speed variations in various canyonlike urban forms. The thermal comfort requirements for lightly-dressed, moderately-walking/seated persons in the outdoor space in summer are then obtained using the ITS. model. The proposed methodology enables a first-order assessment of the climatic implications of different features of the physical structure of the city such as street orientation, canyon height-to-width ratio, building density, and street shading. The application of the proposed methodology is demonstrated for Tel Aviv.

Thermal comfort sensing device

Abstract: A temperature comfort sensing device and a method for manufacturing the same, capable of achieving comfortable air conditioning by detecting an average temperature comfort sensitivity to a room environment and thus analogizing a correct predicted mean vote value. The temperature comfort sensing device comprises a lower diaphragm having a thin film heater and a temperature sensor, and an upper diaphragm having a plurality of thermocouples, a room temperature sensor and a black body. Alternatively, the temperature comfort sensing device comprises a single diaphragm having a thin film heater and a temperature sensor. Directly formed over the single diaphragm are a plurality of thermocouples, a room temperature sensor and a black body. The sensor is based on a model of the human body, with the thin film heater corresponding to an internal heat exchanging mechanism of a human being. The thermocouples serve to sense a skin temperature condition.

The Effects Of Air Temperature And Relative Humidity On Thermal Comfort In The Office Environment

Abstract: The objective of this study was to assess the effect of air humidification and temperature on thermal comfort in sedentary office work. A blinded twelve-period cross-over trial was carried out in two similar wings of an office building, contrasting 28–39% steam humidification with no humidification, corresponding to 12–28% relative humidity. The length of each period was one working week. The study population was 169 workers who judged their thermal sensations in a weekly questionnaire. The percentage of dissatisfied was lowest when the air temperature was 22 °C. At 22 °C an increase in relative humidity raised the mean thermal sensation only slightly. At 20 °C when the air was humidified there were fewer workers who judged their air temperature as being too low. On the other hand, at 24 °C humidification increased the percentage of workers who judged their air temperature to be too high. The percentage of dissatisfied increased rapidly when the air temperature was outside of its optimum value, 22 °C. The percentage of workers complaining about draft increased when the air temperature was lower than 22 °C. Thus we consider that the temperature range from 20 to 24 °C during wintertime may be too wide without individual temperature control from the point vzew of thermal comfort. We recommend that the air temperature should be kept between 21 and 23 °C if no individual control is available. The best solution would be individual temperature control permitting adjustment of the temperature at 22 ± 2 °C.

A study of occupant comfort and workstation performance in PG&E's advanced office systems testbed

Abstract: Author(s): Bauman, Fred; McClintock, Maurya | Abstract: This final report presents the results of research completed since June 1991 on PGaE's Advanced Office Systems Testbed (AOST) Project. The initial advanced office system selected for evaluation in the AOST office was the Personal Environmental Module (PEM), manufactured by Johnson Controls. The PEM represents one example of an emerging technology known as task conditioning, or localized thermal distribution (LTD). Workstation-based LTD systems that allow individuals a degree of control over their local environment have the potential to improve the energy efficiency of the building's air distribution system by enabling only the local workstation environments to be tightly controlled while relaxing the energy and comfort requirements in the less critical surrounding spaces.Work was performed by UC Berkeley in the following task areas: (1) detailed field measurements of thermal comfort of the PGaE employees participating in the study, both before and after moving into the AOST office; (2) installation of a permanent data acquisition and information display system capable of recording and displaying the status of a selected number of performance parameters from the AOST office, including occupant use patterns from each of the eight workstations, supply and return conditions from the air distribution system serving the office, and average room air conditions; (3) analysis of the collected data; and (4) evaluation of the applied measurement methods.

Raumklima und thermische Behaglichkeit

Abstract: Although human beings are certainly to adopt, or «acclimatize», to differences in atmospheric air conditions, there are nonetheless specific circumstances in which people feel at their best: the «comfort range». This feeling of comfort is subject to a number of influencing favors suds as age, season, dress, state of health, lighting, etc. Physical elements also exert an influence however. Numerous climate-induced factors have an influence on people's feeling of well-being: They are described collectively using the term thermal comfort». Despite this large range of differing parameters, it is still possible to define air-state value of which most people, on average, feel comfortable. Essentially, these quantify air temperature and this uniformity of distribution in the room, mean wall temperature (including the temperatures of window and heating device surfaces), air humidity and air movement. Guideline figures are supplied in the corresponding DIN standards. These interacting parameters are described in the present article

Standards for design and evaluation of the indoor thermal environment

Abstract: The air temperature alone and, in some cases, the operative temperature are not sufficient to evaluate the thermal environment. Based on many years of research, national and international standards such as ASHRAE Standard 55 and ISO Standard 7730 have been established. Both standards have recently been revised and are currently available. When evaluating a given thermal environment to see whether it fulfills the requirements recommended in the standards, it is necessary to measure the different thermal parameters. The requirements for instrumentation and methods to perform these measurements are also specified in ASHRAE Standard 55 and in ISO Standard 7726. This article describes the methods and requirements included in the above standards. The differences between the ASHRAE and ISO standards will also be discussed.

Human thermal comfort in tropical climates

Abstract: There is considerable disagreement in the research community concerning whether comfort standards developed in the temperate climates of Europe and North America are appropriate for use in countries with more extreme climatic conditions. This is because some researchers, mainly employing thermal chamber methods, have found that thermal comfort is independent of geographical locations, while other researchers using the field method have found that thermal comfort is dependent on local average ambient conditions. It is also well-known that air-conditioned buildings in tropical countries are overcooled to western standards. This thesis sets out to develop a recommended Thermal Comfort Zone for Malaysia, based on the thermal comfort votes of Malaysians in their own country. Secondly, the thesis determines whether there is any significant difference between the votes of different ethnic and gender groups of Malaysians. The tests also compare the significance between the thermal sensation and the thermal comfort votes of each group. Finally, the study determines whether acclimatisation affects the voting trends of Malaysians by comparing the votes of Malaysian students in Malaysia with those of Malaysian students in the U.K.

Thermal comfort requirements in hot dry regions with special reference to Riyadh, Part 1: for university students

Abstract: SYNOPSIS Due to the availability of relatively cheap energy a large number of buildings in the Gulf States depend totally on mechanical air-conditioning for controlling the indoor environment (ie, cooling during the hot season and heating during the cold season) At home most people are free to choose the preferred environment, but when it comes to public buildings—commercial, office, governmental, or educational buildings—the thermostat of the central air-conditioning is set to what is believed to satisfy optimum thermal comfort for most of those who are using the building This study is an attempt to define thermal comfort requirements of university students and investigate their response towards their indoor environment The students of the College of Architecture and Planning, and the College of Engineering at King Saud University, Riyadh were selected as subjects for the case study The field survey was composed of two main parts The first part dealt with monitoring and recording the main environm

Silicon infrared sensors for thermal comfort and control

Abstract: Obtaining a satisfactory comfort level is becoming increasingly important to building owners. Today, comfort control typically means using the space temperature to control space conditions. However, in the near-future, comfort control will mean measuring sensible temperature, radiant temperature, humidity and velocity, then calculating a comfort value, and controlling conditions of the space. The main factors affecting individual worker comfort are more easily measured than others. For example, radiant temperature is a relatively difficult and expensive measurement to make because of the cost of radiant sensors. Accordingly, this article describes a low cost infrared (IR) radiant sensor that is based on silicon microstructure technology. The importance of radiant temperature to comfort is also discussed.

Hydronic radiant cooling: Overview and preliminary performance assessment

Abstract: A significant amount of electrical energy used to cool non-residential buildings is drawn by the fans used to transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the building by separating ventilation and thermal conditioning. Due to the physical properties of water, hydronic distribution systems can transport a given amount of thermal energy using less than 5% of the otherwise necessary fan energy. This savings alone significantly reduces the energy consumption and especially the peak power requirement This survey clearly shows advantages for radiant cooling in combination with hydronic thermal distribution systems in comparison with the All-Air Systems commonly used in California. The report describes a literature survey on the system`s development, thermal comfort issues, and cooling performance. The cooling power potential and the cooling power requirement are investigated for several California climates. Peak-power requirement is compared for hydronic radiant cooling and conventional All-Air-Systems.

Air movement and thermal comfort: The new ASHRAE Standard 55 provides information on appropriate indoor air velocities for occupant comfort

Abstract: Air movement and thermal comfort The new ASHRAE Standard 55 provides) information on appropriate indoor air velocities for occupant comfort By Marc E. Fountain and Edward A. Arens, Ph.D. Associate Member ASH RAE Member ASHRAE ecent I-{VAC design innovations, energy conservation concerns and new laboratory data on drafts have brought substantial attention to the issue of acceptable levels of air movement in office environments. Air movement may provide desirable cooling in warm conditions, but it may also increase the risk of unacceptably cool drafts. Detectable air movement may be perceived by the occupants as provid- ing freshness and pleasantness to the breathing air, yet it may also be perceived as annoying. Clearly, a specific air speed has many possible physiological and subjective con- sequences. These range from a pleasant sense of coolness to an unpleasant sense of draft, depending on the air temperature, mean radiant temperature, humidity, cloth- ing, metabolic rate and air movement preference of the occupant. Since the turn of the century, ASH- RAE and themial comfort researchers have worked to define levels of air movement that are acceptable to the widest possible group of individuals within an evolving architectural setting, and to incorporate these results into an indoor environmental standard. This article outlines the current state of this discussion. Reference is also made to research investigating the effect of air movement on thermal comfort and the development of air velocity limits in the latest AS}-IRAE thermal comfort standard. Why is air velocity important? HVAC engineers design systems to move energy and ventilating air through buildings. Many, if not most, commercial buildings built since the middle of this century use air distribution systems to deliver heated and/or cooled air to occu- pied spaces. Accordingly, ASHRAE and other organizations have produced standards and guidelines for distributing this air. Included in these documents are specifics such as: volume of air per unit time, percentage of outdoor air, and type and location of duct outlets. In general, design recommendations have favored specifying delivered cfm per square foot of occupied space rather than specifying air velocity for achieving thermal comfort. However, the desired end-product of HVAC systems is not cfm per square foot, a cooled building interior or air move- ment per se; it is the comfort, health and satisfaction of building occupants. Beyond special cases such as laborato- ries and clean rooms, efforts in I-{VAC are primarily directed at producing thermal comfort and air quality that are acceptable for breathing. The focus of this article is the influence o-f the air movement (created by an HVAC system) on thermal comfort. Air velocity is one of six main varia- bles affecting human themtal comfort. The other five include three physical variables (air temperature, mean radiant temperature and relative humidity) and two behaviorally regulated variables, (metabolic rate and clothing insulation). In humans, the thermoregulatory sys- tem is responsible for maintaining the heat balance of the body using a core setpoint of 98.6 °F (37 °C) within the constraints of the _ six variables given above. This system con- trols the release of metabolic heat by regulating skin temperature, primarily by varying skin blood supply and sweating at the skin surface. Convective heat transfer at the skin varies with surface temperature and local air motion across the skin surface. Exten- sive laboratory studies have shown that thermal sensation vote (an important method for measuring thermal comfort) is closely related to skin temperature in cool and comfortable conditions. In warm and warm-humid conditions, moisture on the skin has a strong effect on thermal sensa- tion, particularly after sweating mechan- isms have been triggered. About the authors Marc E. Fountain is a PhD candidate at the University of Califomia—Berkeley (UCB). He received his BA in physics from UCB. ASHRAE it 2.1 (Physiology and Human ‘ Environment) and has been active in ther- mal comfort research since 1986 including contributions to ASH RAE Research Projects RP-462 and RP-702. Edward A. Arens is a professor in the Department of Architecture at the Univer- sity of California-—Berkeley and director of the Center for Environmental Design Research. He received his PhD in archi- tectural science from the University of Edinburgh and his undergraduate and masters degrees from Yale University. Arens is serving on the SPC 55-92R Standards Project Committee, and is a corresponding member of TC 2.1 and a past-chairman of TC 25 (Air Flow Around Buildings). Fountain is a corresponding member of l .4 SHR.-1 E Journal August 1993

Evaluation of Air Supply Method by Mathematical Simulation in a Classroom with a Low Ventilation Rate

Abstract: A numerical study has been carried out to predict the indoor air quality and thermal comfort in a classroom with a low ventilation rate. Four different air supply methods were used: Displacement ventilation, well-mixed ventilation, and two types of low-wall-diffuser ventilation. The airflow pattern, predicted percentage of dissatisfied occupants, percentage of dissatisfied people due to draught, CO2 concentration, and percentage of dissatisfied people due to indoor air quality were determined using a program based on a k-Iµ turbulence model. It was found that the secondary flow generated by the buoyancy effect produced by the pupils in the room is much stronger than the primary flow supplied from the diffusers. As a result, the overall ventilation effectiveness and thermal comfort are similar under the four air supply methods, except in the region near the diffusers. Supplying fresh air at a lower level (near the floor) may cause draughts. For an acceptable perceived indoor air quality, the ventilation rate should be increased to meet the requirement stated by ASHRAE Standard 62-1989. © 1993, Sage Publications. All rights reserved.

A Review of Thermal Comfort Studies in Japan

Abstract: More than 50 papers on thermal comfort are presented in various meetings and symposia every year in Japan. Topics covered by these papers include comfort zone, the effect of fluctuating air movement and asymmetric thermal radiation on human responses, the dynamic analysis of human responses, psy chological and behavioral aspects of thermal comfort, and the development of environmental indices, to name a few. This paper briefly reviews these investi gations.

Carbon dioxide prediction model for VAV system part-load evaluation

Abstract: Development of an interactive indoor air quality (IAQ) computer program is particularly helpful in evaluating the more critical variable air volume (VAV) systems, which respond to net space demands for heating and cooling by introducing more or less cooling air into a conditioned space. This article demonstrates the development of such an interactive IAQ/HVAC design computer program. This program is now used by the author's office staff to ensure that ventilation rates selected are capable of satisfying minimum ventilation requirements (in a worst-case scenario in any occupied zone by investigating each zone on a real-time, hourly basis, etc.) and still maintain satisfactory balance between IAQ and energy consumption levels. A step-by-step procedure of their proposed dynamic modeling methodology, employing the alternative IAQ procedure as outlined in paragraph 6.2 of ASHRAE Standard 62-1989 for a ventilation demand-driven system, is described. In addition, estimated time-varying CO[sub 2] concentrations for a representative Los Angeles high-rise office building, the VAV system of which was recently analyzed (employing various outside design air flow rates ranging from 15 through 20 cfm per person) is presented. Estimated CO[sub 2] concentration levels are then be compared to those actually measured through monitoring (once the building is occupied) andmore » can also be used to facilitate IAQ commissioning. This IAQ compliance computer program simultaneously evaluates both thermal comfort and IAQ criteria for various building occupancies.« less

Older adults: clothing preferences for thermal comfort in cold weather

Abstract: Escalating energy prices and widely publicized energy saving practices in the last decade have induced some older consumers to lower household temperatures during cold weather. Therefore, the effective manipulation of clothing warrants consideration in maintaining thermal body comfort. The purpose of this research was to determine the clothing preferences of elderly consumers indoors during cold weather. Four hundred and fifty questionnaires were administered at three locations. Results from the study revealed that comfort was the most significant factor in selecting warm clothing. Although the respondents had implemented the effective use of clothing to achieve thermal comfort, the use of supplemental heat, and control of thermostat setting for heat was more prevalent. Suggestions and recommendations are made for practitioners who would address the issues of clothing for thermal comfort and energy conservation.

Air movement, comfort and ventilation in partitioned workstations

Abstract: Today's office designs, technologies and work processes make it increasingly difficult for conventional HVAC systems to satisfy the environmental needs of office workers--especially as those workers more openly express personal preferences about air quality and comfort In an open-plan office workplace, the design and configuration of furniture and partitions can, in certain cases, influence the thermal and airflow conditions in workstations Some researchers believe that partitions separating workstations may obstruct airflow, resulting in poorly ventilated workstations Modern offices may also have large amounts of heat-generating equipment within workstations, requiring substantial airflow for heat removal Frequent reconfiguration of the geometric layout and thermal loads of open-plan offices places additional demands on the HVAC system Data from several recent surveys of occupants of large office buildings identify indoor air quality and air circulation as two significant elements that contribute to worker comfort and satisfaction A 1989 Environmental Protection Agency survey of its own buildings found that 48% of the respondents from one facility brought portable fans to their offices This body of research seems to indicate that lack of air movement is one of the most common complaints in office environments The lack of air movement is frequently attributed to the configurationmore » of workstations in open-plan designs This article presents the major results of a study examining the comfort and ventilation conditions in workstations surrounded by partitions and ventilated by a conventional ceiling supply-and-return air distribution system The study investigated a wide range of partition configurations and environmental parameters in an attempt to bring greater thoroughness to the testing methodology and to yield a more clearly substantiated conclusion on the role of partitions in air circulation« less

Separate HVAC systems maximize energy efficiency

Abstract: This article describes an energy efficient variable air volume HVAC system for a university research laboratory. The features described include the fume exhaust system, laboratory HVAC system, office HVAC system, corridor control, environmental chambers, indoor air quality, smoke control, thermal comfort, cost effectiveness, and operation and maintenance.

Air movement and thermal comfort - eScholarship

Abstract: and Airmovement thermalcomfort on information ThenewASHRAE Standard provides comfort indoor air velocities occupant appropriate for By Marc E. Fountain and Mward A. Arens, Ph.D. MemberASHRAE Associate MemberASHRAE heat of Many, notmost, if commercial trolsthe release metabolic by design innovations, buildings. ecent HVAC primarily by skin the of builtsince middle this regulating temperaturg concerns buildings conservation energy and at skin supply sweadng to use systems varying blood dataon century air distribution and newlaboratory heated and/or cooled to occu- theskinsurface. air have brought substantial deliver drafrs heat at Convective transfer ihe skin lEvels to of attention theissue acceptable ol piedspaces. with surface and temperature local Accordingly', ASHRAEand other varies in air movement officeenvironments. Exten- across skinsurface the have and air motion sunduds desirable organizations produced mayprovide Air movement have shor.r'n that studies for this but also guidelines distributing air.Included sivelaboratory conditions, it may cooling u,alm in vote such documents specifics as: thermalsensation (an important are cool in these the increase riskof unacceptably thermal comfort) is percentage method measuring for of of may Detectable movement be volume airperunittime, air drafts. in related skintemperature cool to of perceived the occupants provid- outdoor andtype location duct closely ail and as by conditions. warmand In andcomfonable to ing freshness pleasantness the outlets. and warm-humid moisture the on conditions, In general, design recommendations as be air, breathing ya it mayalso perceived effect thermal on sensa- cfm have favored specifying deiivered per skinhasa strong annoying. after mechan- than tion,particularly sweating foot space a air has Clearlll specific speed many square of occupied rather triggered. have been airvelocity achieving for thermal isms possible physiological subjective con- specifying and Howwer, desired the end-product froma pleasant comfon. These sequences. range is to sense of sense coolness anunpleasant of oi HVACsystems not cfmper square About theauthon interior air move- or dnft, depending theair emperaturg foot,a cooledbuilding on and it health humidit v, cloth- mentperse; is thecomfort, radiant ternpeftlturg mean at MarcE. Founsinisa PhDcandidate the of (UCB). occupants. ing, metabolic and air movement satisfaction building rate Uniwnity of Califomia-Berkelry preference theoccupant. from Beyond special such laborato cases as his Hereteived BA in physics UCB. of member Fountain a corrsponding is of rooms, in ASH- riesandclean efforts HVACare the Since turnof thecentury, and ASHRAE 1.1(Ph.vsiology Human TC directed producing at thermal have primarily comfon rerarchers RAEandthermal active ther- and been in and that acceptable Environment) has worked define to levels air movement comfort airquality are of since induding malcomfon research 1986 possible for breathing. focus this isthe The anicle of thatareaccepuble thewidest to t s c o n t r i b u t i o n o e S H R A ER e s e a r c h (created group indiriduals b1' within evolving influence theairmovement of oi an Projects RP{62andRP-702 system) thermal on comfort. and architectural serting, to incorporate an HVAC in A. Edu'ard Arensis a professor the Air velocity oneof sixmainvaria- is these results anindoor into elvironmental at Depanment fuchitecture theUniver- of The bles affeaing human thermal comfort. standard. and physical variables sityof California-Berkeley direoor three Thisanicleoutlines current the state otherfiveinclude Design of the Centerfor Environmental mean temperature to (airtemperature radiant Referenceis made also of thisdiscussion. his Raearch. received PhDin archi- He humidity) tr+o and behavionlly investigating effectof air andrelatirre the research fromthe University tectural science of (metabolic and variables rate and movement thermal on comfort the regulated Edinburgh hisundergraduate and and insulation). dwelopment air velocity of limitsin the clothing manen from degrees lhleUniversiry sys- In humans, thermoregulatory the comfort latesr ASHRAE thermal standard. Sundards is serving the SPC-i5-92R on temisresponsible maintaining heu the for hoia Committee, isa conespmding and Whyisair velocity important? a of balance thebodyusing core ol setpoint member TC2.1anda past+hairman of of (37 C) withintheconstrainu the of to design TC 25 (Air FlowAroundBuildines). HVACengineers systems 98.6 F given This con- move and air energy ventilating through sixvariables above system H 1 . 1 R I E J o u n a l A u g u s rI 9 9 3