ASHRAE Journal - March 2022 - 34
ASHRAE AWARD OF ENGINEERING EXCELLENCE
FIGURE 4 Hybrid HVAC system by AHU and TWU.
Return Duct/Bypass Duct
Supply Duct
Plenum Chamber
SA
Railway
Noise
EA
EA
SA
RA EA
Exhausted Through the
Baseboard Slit
Through-Wall Units (TWU)
(Perimeter AC)
(PMV) of each air-conditioning mode in each season was
well within the comfort zone.
In such a hybrid air-conditioning system, in terms of
thermal comfort and energy savings, the temperature
setting of the AHUs and TWUs were investigated under
different conditions in each season to determine the
appropriate setpoint. As an example, operative temperature
and absolute humidity within the offi ce were plotted
to compare with the comfort zone of ANSI/ASHRAE
Standard 55-2013 , Thermal Environmental Conditions for
Human Occupancy. In summer, the TWU 24°C (75°F)
condition was cold underfoot, and the distributions are
outside of the comfort zone in the perimeter zone, and
lowering the temperature setting lowers the operative
temperature. Therefore, the TWU 26°C (79°F) condition
was more desirable, because interior/perimeter temperatures
were within the comfort zone for the 0.5 clo occupant,
and the PMVs were within the comfort range. Even
during heating conditions, the vertical air temperature
difference between fl oor level (FL) +0.1 m (0.33 ft) and
FL+1.1 m (3.61 ft) both in the interior and in perimeter
was less than 2°C (3.6°F). It was confi rmed that both the
interior and perimeter were within the comfort range of
" Category A " defi ned by ISO.
The perimeter zone is a challenging thermal environment,
but showed higher values from the results of thermal
comfort and sensation when compared to the interior
zone. The TWUs are located at the perimeter, and
the increased self-effi cacy due to the freely adjustable
temperature environment may have had an effect on the
34
ASHRAE JOURNAL ashrae.o rg M A R C H 2 0 2 2
RA
SA
Slight Airfl ow During
Cooling
Natural Ventilation from
Common Areas
OA Section
AHU With a High Performance Filter (MERV 13) That Separates the OA
and RA Sections for Good Air Quality, Dehumidifi cation and Humidifi cation
satisfaction of those who had seats near the perimeter,
compared to those who had seats in the interior.
Innovation
A signifi cant innovation was to develop a new hybrid
AC system of a central AHU for the interior zone and the
perimeter TWUs, which reinforced resiliency in both
daily energy use and emergencies (Figure 4). A new TWU
was developed by adding an exhaust operation function
that uses heat recovery of indoor exhaust air to the heat
exchanger of the compressor in place of the conventional
type, which is unable to bring outside air into the
room or exhaust indoor air. The innovations compared
to the conventional unit are as follows:
1. Conditioned air is supplied to the offi ce by the AHU,
and indoor air is exhausted by the TWUs, thus exhausting
indoor air across the entire façade. The TWUs
recover heat from the indoor exhaust air by a compressor
for enhancing AC effi ciency. Exhausting indoor air
improved the effi ciency by approximately 30% compared
to a standard unit.
2. The TWU's operating pattern can be organized as
shown in Figure 5. The operation pattern of the TWU
changes so that the CO2 concentration in the room
becomes the control value. During the fresh air cooling
mode by the AHU and TWU, the fresh air introduced is
exhausted from the outdoor fan of the TWUs, which is
in exhaust mode. The ventilation system performance
produced by these TWUs achieved unidirectional airfl ow
to the windows and does not stir or mix the indoor air.
RA
SA
VAV
SA
Air-Handling Unit (AHU)
RA
Supply Fan
RA Section
Motor Damper for
Fresh Air Cooling
OA
RA
2022
http://ashrae.org
ASHRAE Journal - March 2022
Table of Contents for the Digital Edition of ASHRAE Journal - March 2022
ASHRAE Journal - March 2022 - Intro
ASHRAE Journal - March 2022 - Cover1
ASHRAE Journal - March 2022 - Cover2
ASHRAE Journal - March 2022 - 1
ASHRAE Journal - March 2022 - 2
ASHRAE Journal - March 2022 - 3
ASHRAE Journal - March 2022 - 4
ASHRAE Journal - March 2022 - 5
ASHRAE Journal - March 2022 - 6
ASHRAE Journal - March 2022 - 7
ASHRAE Journal - March 2022 - 8
ASHRAE Journal - March 2022 - 9
ASHRAE Journal - March 2022 - 10
ASHRAE Journal - March 2022 - 11
ASHRAE Journal - March 2022 - 12
ASHRAE Journal - March 2022 - 13
ASHRAE Journal - March 2022 - 14
ASHRAE Journal - March 2022 - 15
ASHRAE Journal - March 2022 - 16
ASHRAE Journal - March 2022 - 17
ASHRAE Journal - March 2022 - 18
ASHRAE Journal - March 2022 - 19
ASHRAE Journal - March 2022 - 20
ASHRAE Journal - March 2022 - 21
ASHRAE Journal - March 2022 - 22
ASHRAE Journal - March 2022 - 23
ASHRAE Journal - March 2022 - 24
ASHRAE Journal - March 2022 - 25
ASHRAE Journal - March 2022 - 26
ASHRAE Journal - March 2022 - 27
ASHRAE Journal - March 2022 - 28
ASHRAE Journal - March 2022 - 29
ASHRAE Journal - March 2022 - 30
ASHRAE Journal - March 2022 - 31
ASHRAE Journal - March 2022 - 32
ASHRAE Journal - March 2022 - 33
ASHRAE Journal - March 2022 - 34
ASHRAE Journal - March 2022 - 35
ASHRAE Journal - March 2022 - 36
ASHRAE Journal - March 2022 - 37
ASHRAE Journal - March 2022 - 38
ASHRAE Journal - March 2022 - 39
ASHRAE Journal - March 2022 - 40
ASHRAE Journal - March 2022 - 41
ASHRAE Journal - March 2022 - 42
ASHRAE Journal - March 2022 - 43
ASHRAE Journal - March 2022 - 44
ASHRAE Journal - March 2022 - 45
ASHRAE Journal - March 2022 - 46
ASHRAE Journal - March 2022 - 47
ASHRAE Journal - March 2022 - 48
ASHRAE Journal - March 2022 - 49
ASHRAE Journal - March 2022 - 50
ASHRAE Journal - March 2022 - 51
ASHRAE Journal - March 2022 - 52
ASHRAE Journal - March 2022 - 53
ASHRAE Journal - March 2022 - 54
ASHRAE Journal - March 2022 - 55
ASHRAE Journal - March 2022 - 56
ASHRAE Journal - March 2022 - 57
ASHRAE Journal - March 2022 - 58
ASHRAE Journal - March 2022 - 59
ASHRAE Journal - March 2022 - 60
ASHRAE Journal - March 2022 - 61
ASHRAE Journal - March 2022 - 62
ASHRAE Journal - March 2022 - 63
ASHRAE Journal - March 2022 - 64
ASHRAE Journal - March 2022 - 65
ASHRAE Journal - March 2022 - 66
ASHRAE Journal - March 2022 - 67
ASHRAE Journal - March 2022 - 68
ASHRAE Journal - March 2022 - 69
ASHRAE Journal - March 2022 - 70
ASHRAE Journal - March 2022 - 71
ASHRAE Journal - March 2022 - 72
ASHRAE Journal - March 2022 - 73
ASHRAE Journal - March 2022 - 74
ASHRAE Journal - March 2022 - 75
ASHRAE Journal - March 2022 - 76
ASHRAE Journal - March 2022 - 77
ASHRAE Journal - March 2022 - 78
ASHRAE Journal - March 2022 - 79
ASHRAE Journal - March 2022 - 80
ASHRAE Journal - March 2022 - 81
ASHRAE Journal - March 2022 - 82
ASHRAE Journal - March 2022 - 83
ASHRAE Journal - March 2022 - 84
ASHRAE Journal - March 2022 - 85
ASHRAE Journal - March 2022 - 86
ASHRAE Journal - March 2022 - 87
ASHRAE Journal - March 2022 - 88
ASHRAE Journal - March 2022 - Cover3
ASHRAE Journal - March 2022 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ATMAHK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VHQRAW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XGMDXI
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_YELQLJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QJLWMC
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