ASHRAE Journal - December 2009 - 53

ASHRAE59–2009 YE A R S JOURNAL charge on each dirt particle. Next the air goes between collector plates which carry 6500 volt positive and negative charges. The positively charged dirt particles are repelled from the positively charged plates and attracted to the negative plates. At 500 fpm, an electronic air cleaner can remove 90 percent of particles 0.01 micron and larger; at lower velocities the cleaner eliminates over 95 percent of these particles. (Percentages are from the National Bureau of Standards dust-spot tests.) The NBS dirt-removal test is used because it reflects the dirt-removing properties of various air cleaners. As the NBS report1 says: Dust particles may be divided into two categories: coarse and fine. Coarse particles are those which are deposited by gravity on horizontal surfaces. Fine particles are those which are deposited on walls and ceilings, independent of gravity. It has been determined that the coarse particles contribute practically all of the weight of a dust mixture, while the fines contribute practically all of the number of particles in a dust mixture. If, therefore, a weight method is used to determine filter arrestance, almost any mechanical filter could be designed to obtain arrestances of 95 percent or better, although the number of fine particles would not be materially reduced. Since it is noticeable that the fine particles cause most of the discoloration problem in buildings, the arrestance of such a filter would approach zero in combating discoloration. A filter test based solely on determination of weight removal is of little value when selecting a filter for air distribution in conditioned spaces. The discoloration test or dust-spot method is the only acceptable method of testing filters presently in use. One of the major reasons for filter tests is to compare the various types of filters. The NBS ‘Dust Spot Method’ allows an intertype comparison of filters which can be conducted using the same apparatus and any of the nonliquid aerosols. These tests definitely show the differences between filters of different types, as well as between filters of the same type operating under the same conditions. While an electronic air cleaner will remove dirt in the air, it cannot, however, eliminate molecular odors and gases. Basically, there are two ways to get rid of an odor— it can be chemically “masked” or it can be eliminated. December 2009 F i g . 1 Operating principle of an electronic air cleaner shows why its cleaning efficiency greatly exceeds that of ordinary mechanical filters. Air flowing into the cleaning cell first passes through the ionizer. Here all dirt particles, no matter how small, are given an electrical charge. They are then carried by the air into the cell’s collector unit, where parallel plates of opposite electrical charge attract and hold particles, just like a magnet collects iron filings. F i g . 1 A Face of electronic air cleaner, photographed before installation, shows how cells join together like building blocks, forming a single unit sized to the air-handling system. The traveling washing manifold (with hoses attached) normally rests at the side of the cleaner, out of the airstream. When washing starts, the manifold moves across the cells and cleans them with water sprayed from its nozzles. A second set of nozzles then sprays adhesive into the cells. In the next washing, the adhesive dissolves readily in the water spray and carries all collected dirt from the cell. ASHRAE Journal

ASHRAE Journal - December 2009

Table of Contents for the Digital Edition of ASHRAE Journal - December 2009

ASHRAE Journal - December 2009
Contents
Commentary
Industry News
Letters
Meetings and Shows
ASHRAE Building EQ Program
Feature Articles
A Closer Look at Chiller Ratings
Cooling With Less Air: Using Underfloor Air Distribution and Chilled Beams
Cooling Concrete: Containerized Water Chilling Plant
Geothermal for Community Center
Anniversary Feature: Air-Recovery System Versus Conventional Air Conditioning
Technical Topics
New Product Preview
Products
Emerging Technologies
Washington Report
People
Special Products
2009 Feature Articles Indices
Classified Advertising
Advertisers Index
ASHRAE Journal - December 2009 - ASHRAE Journal - December 2009
ASHRAE Journal - December 2009 - Cover2
ASHRAE Journal - December 2009 - 1
ASHRAE Journal - December 2009 - 2
ASHRAE Journal - December 2009 - Contents
ASHRAE Journal - December 2009 - 4
ASHRAE Journal - December 2009 - Commentary
ASHRAE Journal - December 2009 - Industry News
ASHRAE Journal - December 2009 - 7
ASHRAE Journal - December 2009 - 8
ASHRAE Journal - December 2009 - 9
ASHRAE Journal - December 2009 - 10
ASHRAE Journal - December 2009 - Letters
ASHRAE Journal - December 2009 - 12
ASHRAE Journal - December 2009 - 13
ASHRAE Journal - December 2009 - 14
ASHRAE Journal - December 2009 - 15
ASHRAE Journal - December 2009 - Meetings and Shows
ASHRAE Journal - December 2009 - 17
ASHRAE Journal - December 2009 - Feature Articles
ASHRAE Journal - December 2009 - 19
ASHRAE Journal - December 2009 - 20
ASHRAE Journal - December 2009 - 21
ASHRAE Journal - December 2009 - A Closer Look at Chiller Ratings
ASHRAE Journal - December 2009 - 23
ASHRAE Journal - December 2009 - 24
ASHRAE Journal - December 2009 - 25
ASHRAE Journal - December 2009 - 26
ASHRAE Journal - December 2009 - 27
ASHRAE Journal - December 2009 - 28
ASHRAE Journal - December 2009 - 29
ASHRAE Journal - December 2009 - 30
ASHRAE Journal - December 2009 - 31
ASHRAE Journal - December 2009 - 32
ASHRAE Journal - December 2009 - 33
ASHRAE Journal - December 2009 - Cooling With Less Air: Using Underfloor Air Distribution and Chilled Beams
ASHRAE Journal - December 2009 - 35
ASHRAE Journal - December 2009 - 36
ASHRAE Journal - December 2009 - 37
ASHRAE Journal - December 2009 - 38
ASHRAE Journal - December 2009 - 39
ASHRAE Journal - December 2009 - 40
ASHRAE Journal - December 2009 - 41
ASHRAE Journal - December 2009 - Cooling Concrete: Containerized Water Chilling Plant
ASHRAE Journal - December 2009 - 43
ASHRAE Journal - December 2009 - 44
ASHRAE Journal - December 2009 - 45
ASHRAE Journal - December 2009 - 46
ASHRAE Journal - December 2009 - 47
ASHRAE Journal - December 2009 - Geothermal for Community Center
ASHRAE Journal - December 2009 - 49
ASHRAE Journal - December 2009 - 50
ASHRAE Journal - December 2009 - 51
ASHRAE Journal - December 2009 - Anniversary Feature: Air-Recovery System Versus Conventional Air Conditioning
ASHRAE Journal - December 2009 - 53
ASHRAE Journal - December 2009 - 54
ASHRAE Journal - December 2009 - 55
ASHRAE Journal - December 2009 - 56
ASHRAE Journal - December 2009 - 57
ASHRAE Journal - December 2009 - 58
ASHRAE Journal - December 2009 - 59
ASHRAE Journal - December 2009 - 60
ASHRAE Journal - December 2009 - 61
ASHRAE Journal - December 2009 - Technical Topics
ASHRAE Journal - December 2009 - 63
ASHRAE Journal - December 2009 - 64
ASHRAE Journal - December 2009 - New Product Preview
ASHRAE Journal - December 2009 - 66
ASHRAE Journal - December 2009 - 67
ASHRAE Journal - December 2009 - 68
ASHRAE Journal - December 2009 - 69
ASHRAE Journal - December 2009 - 70
ASHRAE Journal - December 2009 - 71
ASHRAE Journal - December 2009 - 72
ASHRAE Journal - December 2009 - 73
ASHRAE Journal - December 2009 - 74
ASHRAE Journal - December 2009 - 75
ASHRAE Journal - December 2009 - 76
ASHRAE Journal - December 2009 - 77
ASHRAE Journal - December 2009 - 78
ASHRAE Journal - December 2009 - 79
ASHRAE Journal - December 2009 - 80
ASHRAE Journal - December 2009 - 81
ASHRAE Journal - December 2009 - 82
ASHRAE Journal - December 2009 - 83
ASHRAE Journal - December 2009 - 84
ASHRAE Journal - December 2009 - 85
ASHRAE Journal - December 2009 - 86
ASHRAE Journal - December 2009 - 87
ASHRAE Journal - December 2009 - 88
ASHRAE Journal - December 2009 - 89
ASHRAE Journal - December 2009 - 90
ASHRAE Journal - December 2009 - 91
ASHRAE Journal - December 2009 - 92
ASHRAE Journal - December 2009 - 93
ASHRAE Journal - December 2009 - 94
ASHRAE Journal - December 2009 - 95
ASHRAE Journal - December 2009 - 96
ASHRAE Journal - December 2009 - 97
ASHRAE Journal - December 2009 - 98
ASHRAE Journal - December 2009 - 99
ASHRAE Journal - December 2009 - 100
ASHRAE Journal - December 2009 - 101
ASHRAE Journal - December 2009 - 102
ASHRAE Journal - December 2009 - 103
ASHRAE Journal - December 2009 - 104
ASHRAE Journal - December 2009 - 105
ASHRAE Journal - December 2009 - 106
ASHRAE Journal - December 2009 - 107
ASHRAE Journal - December 2009 - 108
ASHRAE Journal - December 2009 - 109
ASHRAE Journal - December 2009 - 110
ASHRAE Journal - December 2009 - 111
ASHRAE Journal - December 2009 - 112
ASHRAE Journal - December 2009 - 113
ASHRAE Journal - December 2009 - Products
ASHRAE Journal - December 2009 - 115
ASHRAE Journal - December 2009 - 116
ASHRAE Journal - December 2009 - Emerging Technologies
ASHRAE Journal - December 2009 - Washington Report
ASHRAE Journal - December 2009 - 119
ASHRAE Journal - December 2009 - People
ASHRAE Journal - December 2009 - Special Products
ASHRAE Journal - December 2009 - 2009 Feature Articles Indices
ASHRAE Journal - December 2009 - 123
ASHRAE Journal - December 2009 - 124
ASHRAE Journal - December 2009 - 125
ASHRAE Journal - December 2009 - Classified Advertising
ASHRAE Journal - December 2009 - 127
ASHRAE Journal - December 2009 - Advertisers Index
ASHRAE Journal - December 2009 - Cover3
ASHRAE Journal - December 2009 - Cover4
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_KTUZMA
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ABEDGD
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201910
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201909
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019septmeber_v2
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019september
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201908
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201907
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201906
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201905
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201904
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019april
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201903
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019march
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201902
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201901
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2019
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018december
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018november
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall_v2
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018october
http://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2018
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201810
http://www.nxtbook.com/nxtbooks/ashrae/ashraeinsights_201806
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201805
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201804
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201803
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201712
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201711
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201710
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall_v2
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201709
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201705
http://www.nxtbook.com/nxtbooks/ashrae/ashrae_meetinginsert_201610
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall_v2
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acrexindia
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer_v2
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer
http://www.nxtbook.com/nxtbooks/amca/2014summer2
http://www.nxtbook.com/nxtbooks/amca/2014summer
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acma_2014summer
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201311
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201309
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acmasupp_2013fall
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201305
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201303
http://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2013winter
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201211
http://www.nxtbook.com/nxtbooks/ashrae/achr_expo_mexico2012
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201209
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v3
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v2
http://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012summer
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201205
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201203
http://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012winter
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201111_v2
http://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201109_v2
http://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2011summer
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201105
http://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201103
http://www.nxtbookMEDIA.com