ASHRAE Journal - October 2010 - 70

emerging technologies	
What are the Benefits and Pitfalls

Personal Ventilation
deliver	heating	or	cooling	and/or	ventilation	air	directly	to	an	individual	 or	individuals,	rather	than	conditioning	an	entire	space.	Air	or	chilled	 water-based	personal	cooling	vests	worn	under	protective	clothing	by	 military	personnel,	firefighters,	workers	in	other	hazardous	environments,	 and	race	car	drivers	are	another	example	of	a	PV	approach.
In the latter set of examples, the combination of a high temperature environment and the high insulation value of the protective clothing create significant heat stress. However, it is costly, impractical, or impossible to provide general space cooling in these environments. For example, the cockpit of a racecar is extremely hot, and a chilled water cooling vest supplied by an ice/chilled water reservoir and a small circulating pump provides effective cooling to the driver, with far less weight, drag, and fuel consumption penalties than are imposed by a vehicle air-conditioning system. The idea behind PV systems for building spaces is the proposition that clean ventilation air and, in some cases, comfort heating and cooling, can be delivered directly to individual occupants more effectively and with less total outdoor ventilation airflow and energy consumption than by traditional mixed ventilation approaches to ventilation and comfort conditioning in commercial spaces, especially office spaces. Mixed ventilation means ventilation by introducing ventilation supply air into a space through diffusers that cause the supply air to mix with the air in the space.
70	 ASHRAE	Journal	

P

By John Dieckmann, Member	ASHRAE; Alissa cooperman; and James Brodrick, Ph.D., Member	ASHRAE

ersonal	ventilation	(PV)	systems	are	one	of	a	number	of	microenvi-

ronment	approaches	to	comfort	heating/cooling	and	ventilation	that	

To apply PV in an office environment with a large number of workstations, conditioned PV air would be provided at each workstation, while the outdoor airflow introduced to the overall space on a mixed basis would be reduced. When saving energy is an objective, heating and cooling temperature setpoints are raised and lowered, respectively, in favor of relying on the conditioned PV air to provide for occupant thermal comfort. The ability of individual occupants to control their own ventilation air delivery and temperature is often cited as a reason why individuals using these systems are more satisfied with the work environment and thermal comfort.

outdoor Ventilation Air Delivery
Personal ventilation systems consist of desk- or ceiling-mounted modules that provide fresh (outside) air to the breathing zone of the workstation occupant. Figure 1 depicts one workstation-based configuration that has been investigated. The goal is to deliver fresh outside air to the breathing zone while mixing as little of the general indoor air of the building (which has accumulated some level of additional CO2 and other indoor pollutants) into this airstream.
ashrae.org	

One tested system1 consists of two desktop-mounted diffusers with 360° of rotation around the vertical and ± 30° adjustment off the horizontal. Each diffuser is installed on either back corner of the desk, similarly to the configuration depicted in Figure 1 (Page 72). Additionally, the system includes an occupancy sensor and incorporates its own fan, power source, and ductwork. The system is able to deliver 9.5 L/s to 71 L/s (20 cfm to 150 cfm) of personal airflow. Another tested system1 has two variable speed fans mounted under the desk, which supply personal airflow. The fans can rotate ±30° off the horizontal. Other configurations of PV fixtures include desk, computer, or ceiling-mounted air delivery terminal units. Desk units can be either desk-mounted diffusers or desk grills that provide the occupant with a personal airflow.2 Yang, et al.,3 tested ceiling-mounted units with a downward directed air nozzle supplied by a ceiling plenum. These ceiling-mounted units allow flexible furniture arrangement. As mentioned previously, the goal of many PV systems has been to supply relatively undiluted fresh outdoor air to the occupants, improving breathing zone air quality and thermal comfort. Particularly if the PV system supplies the relatively low airflow rates required by ASHRAE Standard 62.1 (±7 L/s [±15 cfm] per person, depending on the type of activity in the space) the thermal plume generated by the workstation occupant has a significant effect on the mixture of air that arrives at the breathing zone.3 The temperature difference between the worker and room creates a free convective flow (the thermal plume) that draws air from the surrounding space up and into
	 October	 2010



ASHRAE Journal - October 2010

Table of Contents for the Digital Edition of ASHRAE Journal - October 2010

ASHRAE Journal - October 2010
Contents
Commentary
Industry News
Letters
Meetings and Shows
Using VAV to Limit Humidity at Part Load
Cleanroom Energy Efficiency
Ultra-Low GWP Refrigerants Global Regulations and Standards
HVAC for Prisons
ASHRAE Research Report
ASHRAE Honor Roll
Solar ZEB Project
Emerging Technologies
IAQ Applications
Commissioning
Washington Report
Special Products
Classified Advertising
Advertisers Index
ASHRAE Journal - October 2010 - Intro
ASHRAE Journal - October 2010 - ASHRAE Journal - October 2010
ASHRAE Journal - October 2010 - Cover2
ASHRAE Journal - October 2010 - 1
ASHRAE Journal - October 2010 - 2
ASHRAE Journal - October 2010 - Contents
ASHRAE Journal - October 2010 - Commentary
ASHRAE Journal - October 2010 - 5
ASHRAE Journal - October 2010 - Industry News
ASHRAE Journal - October 2010 - 7
ASHRAE Journal - October 2010 - Letters
ASHRAE Journal - October 2010 - 9
ASHRAE Journal - October 2010 - 10
ASHRAE Journal - October 2010 - 11
ASHRAE Journal - October 2010 - 12
ASHRAE Journal - October 2010 - 13
ASHRAE Journal - October 2010 - 14
ASHRAE Journal - October 2010 - 15
ASHRAE Journal - October 2010 - Meetings and Shows
ASHRAE Journal - October 2010 - 17
ASHRAE Journal - October 2010 - Using VAV to Limit Humidity at Part Load
ASHRAE Journal - October 2010 - 19
ASHRAE Journal - October 2010 - 20
ASHRAE Journal - October 2010 - 21
ASHRAE Journal - October 2010 - 22
ASHRAE Journal - October 2010 - 23
ASHRAE Journal - October 2010 - Cleanroom Energy Efficiency
ASHRAE Journal - October 2010 - 25
ASHRAE Journal - October 2010 - 26
ASHRAE Journal - October 2010 - 27
ASHRAE Journal - October 2010 - 28
ASHRAE Journal - October 2010 - 29
ASHRAE Journal - October 2010 - 30
ASHRAE Journal - October 2010 - 31
ASHRAE Journal - October 2010 - 32
ASHRAE Journal - October 2010 - A1
ASHRAE Journal - October 2010 - A2
ASHRAE Journal - October 2010 - A3
ASHRAE Journal - October 2010 - A4
ASHRAE Journal - October 2010 - A5
ASHRAE Journal - October 2010 - A6
ASHRAE Journal - October 2010 - A7
ASHRAE Journal - October 2010 - A8
ASHRAE Journal - October 2010 - A9
ASHRAE Journal - October 2010 - A10
ASHRAE Journal - October 2010 - A11
ASHRAE Journal - October 2010 - A12
ASHRAE Journal - October 2010 - 33
ASHRAE Journal - October 2010 - Ultra-Low GWP Refrigerants Global Regulations and Standards
ASHRAE Journal - October 2010 - 35
ASHRAE Journal - October 2010 - 36
ASHRAE Journal - October 2010 - 37
ASHRAE Journal - October 2010 - 38
ASHRAE Journal - October 2010 - 39
ASHRAE Journal - October 2010 - 40
ASHRAE Journal - October 2010 - 41
ASHRAE Journal - October 2010 - 42
ASHRAE Journal - October 2010 - 43
ASHRAE Journal - October 2010 - HVAC for Prisons
ASHRAE Journal - October 2010 - 45
ASHRAE Journal - October 2010 - 46
ASHRAE Journal - October 2010 - 47
ASHRAE Journal - October 2010 - 48
ASHRAE Journal - October 2010 - 49
ASHRAE Journal - October 2010 - 50
ASHRAE Journal - October 2010 - 51
ASHRAE Journal - October 2010 - ASHRAE Research Report
ASHRAE Journal - October 2010 - 53
ASHRAE Journal - October 2010 - 54
ASHRAE Journal - October 2010 - 55
ASHRAE Journal - October 2010 - 56
ASHRAE Journal - October 2010 - 57
ASHRAE Journal - October 2010 - 58
ASHRAE Journal - October 2010 - 59
ASHRAE Journal - October 2010 - 60
ASHRAE Journal - October 2010 - 61
ASHRAE Journal - October 2010 - 62
ASHRAE Journal - October 2010 - 63
ASHRAE Journal - October 2010 - 64
ASHRAE Journal - October 2010 - ASHRAE Honor Roll
ASHRAE Journal - October 2010 - HR2
ASHRAE Journal - October 2010 - HR3
ASHRAE Journal - October 2010 - HR4
ASHRAE Journal - October 2010 - HR5
ASHRAE Journal - October 2010 - HR6
ASHRAE Journal - October 2010 - HR7
ASHRAE Journal - October 2010 - HR8
ASHRAE Journal - October 2010 - HR9
ASHRAE Journal - October 2010 - HR10
ASHRAE Journal - October 2010 - HR11
ASHRAE Journal - October 2010 - HR12
ASHRAE Journal - October 2010 - HR13
ASHRAE Journal - October 2010 - HR14
ASHRAE Journal - October 2010 - HR15
ASHRAE Journal - October 2010 - HR16
ASHRAE Journal - October 2010 - HR17
ASHRAE Journal - October 2010 - HR18
ASHRAE Journal - October 2010 - HR19
ASHRAE Journal - October 2010 - HR20
ASHRAE Journal - October 2010 - HR21
ASHRAE Journal - October 2010 - HR22
ASHRAE Journal - October 2010 - HR23
ASHRAE Journal - October 2010 - HR24
ASHRAE Journal - October 2010 - HR25
ASHRAE Journal - October 2010 - HR26
ASHRAE Journal - October 2010 - HR27
ASHRAE Journal - October 2010 - HR28
ASHRAE Journal - October 2010 - HR29
ASHRAE Journal - October 2010 - HR30
ASHRAE Journal - October 2010 - HR31
ASHRAE Journal - October 2010 - HR32
ASHRAE Journal - October 2010 - 64a
ASHRAE Journal - October 2010 - 64b
ASHRAE Journal - October 2010 - 64c
ASHRAE Journal - October 2010 - 64d
ASHRAE Journal - October 2010 - Solar ZEB Project
ASHRAE Journal - October 2010 - 66
ASHRAE Journal - October 2010 - 67
ASHRAE Journal - October 2010 - 68
ASHRAE Journal - October 2010 - 69
ASHRAE Journal - October 2010 - Emerging Technologies
ASHRAE Journal - October 2010 - 71
ASHRAE Journal - October 2010 - 72
ASHRAE Journal - October 2010 - 73
ASHRAE Journal - October 2010 - 74
ASHRAE Journal - October 2010 - 75
ASHRAE Journal - October 2010 - IAQ Applications
ASHRAE Journal - October 2010 - 77
ASHRAE Journal - October 2010 - 78
ASHRAE Journal - October 2010 - 79
ASHRAE Journal - October 2010 - 80
ASHRAE Journal - October 2010 - 81
ASHRAE Journal - October 2010 - 82
ASHRAE Journal - October 2010 - 83
ASHRAE Journal - October 2010 - Commissioning
ASHRAE Journal - October 2010 - 85
ASHRAE Journal - October 2010 - 86
ASHRAE Journal - October 2010 - 87
ASHRAE Journal - October 2010 - 88
ASHRAE Journal - October 2010 - 89
ASHRAE Journal - October 2010 - Washington Report
ASHRAE Journal - October 2010 - 91
ASHRAE Journal - October 2010 - Special Products
ASHRAE Journal - October 2010 - 93
ASHRAE Journal - October 2010 - Classified Advertising
ASHRAE Journal - October 2010 - 95
ASHRAE Journal - October 2010 - Advertisers Index
ASHRAE Journal - October 2010 - Cover3
ASHRAE Journal - October 2010 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_MCDEBX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WNYSQY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XATVOD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FJSHSS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CCBZDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XDEFVG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2023november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2023november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VHGNBL
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WPKBNJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_UUVCDE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTGDEW
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2023
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LKRFXS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_AZSOFG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ERCDBH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QWDFRV
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JHGVDF
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPUYHG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SREIBM
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LRTGLK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OKRFGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2022november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2022november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TZSERA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LVRUIX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RPTVYZ
https://www.nxtbook.com/nxtbooks/ashrae/mini_pub_catalog
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XIYTGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2022
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RFGDOB
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PABXNU
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_REMKLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PICVBT
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_AOYTVW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JQOPLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_IOYTBC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SGAJJF
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_IGHYER
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PDRKLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2021november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2021november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XCODFR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QSLFGO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ILKVNM
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2021
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPDJKD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VJKSRY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDHUTC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JPPKRR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDLTTH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CKLLES
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SLDOX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_HJETUK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OLUHGE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ZERDGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QVMNEO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTPOKE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_BBATRE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_STUBMW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TPEMPE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JNMKDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FBTTPA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WQMMNE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TVBRYN
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2020
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_KTUZMA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ABEDGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201910
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201909
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019septmeber_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019september
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201908
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201907
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201906
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201905
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201904
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019april
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201903
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019march
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201902
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201901
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2019
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018december
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018october
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2018
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201810
https://www.nxtbook.com/nxtbooks/ashrae/ashraeinsights_201806
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201805
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201804
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201803
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201712
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201711
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201710
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201709
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201705
https://www.nxtbook.com/nxtbooks/ashrae/ashrae_meetinginsert_201610
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acrexindia
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer
https://www.nxtbook.com/nxtbooks/amca/2014summer2
https://www.nxtbook.com/nxtbooks/amca/2014summer
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acma_2014summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201311
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201309
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acmasupp_2013fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201305
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201303
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2013winter
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201211
https://www.nxtbook.com/nxtbooks/ashrae/achr_expo_mexico2012
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201209
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v3
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201205
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201203
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012winter
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201111_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201109_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2011summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201105
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201103
https://www.nxtbookmedia.com