Showerhead amenities for reduced energy use and standardization of hot water conservation Masayuki Mae Associate Professor, The University of Tokyo Akinori Suzuki Tokyo Gas Company, Ltd. Yuhi Murakami Graduate student, Tokyo University of Science Yuki Mori Graduate student, Tokyo University of Science Takashi Inoue Professor, Tokyo University of Science Shizuo Iwamoto Professor, Kanagawa University Takashi Kurabuchi Professor, Tokyo University of Science Masayuki Otsuka Professor, Kanto Gakuin University Japan Valve Manufacturers’ Association Nov 3-5, 2013 At ACEEE Hot Water Forum, Atlanta, GA
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Showerhead amenities for reduced energy use and standardization of hot water conservation
Masayuki Mae Associate Professor, The University of Tokyo
Akinori Suzuki Tokyo Gas Company, Ltd.
Yuhi Murakami Graduate student, Tokyo University of Science
Yuki Mori Graduate student, Tokyo University of Science
Takashi Inoue Professor, Tokyo University of Science
Shizuo Iwamoto Professor, Kanagawa University
Takashi Kurabuchi Professor, Tokyo University of Science
Masayuki Otsuka Professor, Kanto Gakuin University
Japan Valve Manufacturers’ Association
Nov 3-5, 2013 At ACEEE Hot Water Forum, Atlanta, GA
2
Energy consumption trends in Japan
・Industrial sector: Improved energy savings as a result of oil shock; 0.9 times 1973 level・Civilian sector: Seeking increased convenience and comfort; 2.4 times 1973 level
Revised energy standards, resulting from the Great East Japan Earthquake
Source: Energy Whitepaper 2013, METI
0.0
100.0
200.0
300.0
400.0
500.0
600.0
0
2
4
6
8
10
12
14
16
18
73 75 80 85 90 95 00 05 11
(1018J)
(年度)
(兆円、2005年価格)
42.8%
19.6%
23.3%
x2.4 from increased
GDP, 1973–2011
Business
14.2%
Transport
Residential
Industrial65.5%
9.2%
16.4%
8.9%
x1.9
Increase(Fiscal 1973
→2011)
x2.8
x0.9
x2.1
x2.4
Drastic enhancement of energy-saving and power-saving measures
Fisical year
Trillion yen
3
Source: Energy Whitepaper 2013, Agency for Natural Resources and Energy
Source: Nakahama et al. (2009) “Measurement of bathtub water consumption for bathing (Part 4),” Proceedings of the Air Conditioning and Sanitary Engineers Annual Meeting
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Shower
108L
Non-bathfaucet
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
120L
149L
Bath
Residential energy consumption in Japan
Residential energy consumption breakdown Hot water consumption, 4-member family (n=47)
Energy-saving measures are needed in the civilian sector
From regulation of only residential insulation to primary energy regulation
Fiscal 201138,358×
106 J/home
Heating28.3%
Kitchen8.1%
Lighting, etc.34.7%
Cooling2.2%
Hot water28.3%
4
Residential energy reduction attempts in Japan
(Old) energy conservation standards
Amended energy conservation standards
1980
Revision
Oil shock
Introduction of (voluntary) standards, based on judgment of home builders・ Definition of hot water equipment (standards A (manual cutoff) / B (low flow spout))・Addition of primary energy consumption standard to insulation standards
Rational use of energy resources1992 New energy-saving standards
Next-generation energy-saving standard
Strengthened residential standards for primary energy consumption in addition to envelope thermal performance Hot water / AC / Ventilation / Lighting / Elevators
・High-efficiency water heaters・High-insulation bathtubs・Solar water heaters・Installation/replacement of low-use hot water equipment
1999
2006 Revision
2009
2013
Meeting standards requires… High energy-saving effects for construction costs; rapid adoption expected
Reason: 1. Taking the mean of optimal flow (1), (4), and (7) considers variation due to measurement conditions. (4) is likely overly large, (7) overly small.
2. (2)(3)(5)(6) not needed for water reduction devices, but measured to compensate for variation in perceived optimal flow rate.
Optimum flow rate is the average of (1), (4), and (7)
Flow
Reduction
Flowmeasurement
method
Avg. optimal flow as measured by monitorCurrent typical flow rate (10 L/min)
Voluntary amenity standards by the Japanese Valve Manufacturers' AssociationQuantitative metrics under consideration for standardization
5
(1) Optimal flow (initial)(2) Max. satisfactory flow(3) Max. usable flow(4) Optimal flow(5) Min. satisfactory flow(6) Min. usable flow(7) Optimal flow
Source: Japan Valve Manufacturers' Association http://www.j-valve.or.jp/
Reduction ratio = (1 – ) x 100
Min. satisfactory flow
(2009 measurement method)
StandardStandard of Judgment for Residential
Construction Clients (2009)
Low-energy standards for homes and buildings
Energy code 2013
DefinitionItems fulfilling reduction standards according to the monitoring method established by the Japan Valve Manufacturers Association
Items meeting standards for low-water construction
Certification Manufacturer measurement and evaluation JIS measurement and certification
Typ
e an
d e
ffec
t
Manualstoppage
(Type A)
Low-flowfaucet
(Type B)
Combined
Japanese shower standards
Low-flow faucet standardscurrently being established
Water is easily stopped by manual operation 20% reduction
Optimal flow of 8.5L/min or less
Push button faucet
Switch shower
Switch
32% reduction
Source: Japan Valve Manufacturers' Association http://www.j-valve.or.jp/
Currently being established
6
15% reduction Spray shower(Low-Flow)
International shower standards
FLOW RATE OTHER REQUIREMENTS STANDARD
Japan Mandatory
Voluntary Common: 10L/min(Optimal flow rate)Hot water saving: Type A ⇒ Quick-stop Function
Type B ⇒ 8.5L/min(Optimal flow rate)Type A B ⇒ Type A and Type B
Effectiveness and comfortOptimum pressure calculated
Japan ValveManufacturers’ Association
USA Mandatory Common: Max. 9.5 L/min(2.5 gpm) at 550 kPaHigh efficiency: Max. 7.6 L/min (2.0 gpm)
Min. 75% of max. at 550 kPa75% of max. at 410 kPa60% of max. at 140 kPa
Spray force: Min. 0.56 N (2.0 oz) @ 140 kPaSpray coverage: ≤75% (φ50~100 mm)
≥25% (φ50~150 mm)
ANSI/ASMEA112.18.1
Voluntary Max. 7.6 L/min (2.0 gpm)Min. 75% of max. at 550 kPa
75% of max. at 310 kPa60% of max. at 140 kPa
EPAWaterSense
High efficiency (prerequisite): 7.6 L/min (2.0 gpm)Very high efficiency (2pt): 6.6L/min (1.75 gpm)
LEED (2009 v3)
EU Mandatory Water run through apparatus and flow rate calculated Type 1: (0,3 + 0,02) MPa (3 + 0,2) barType 2: (0,01 + 0,005) MPa (0,1 + 0,05) barRecord flow rate Q after stabilization
Thermal shock testLeakage testMechanical strength test Rotary connection test
EN1112(2008)
Voluntary Min. flow rate: 6 L/min; max. flow rate: 12 L/min. A and B Rating two criteria: volume and temperaturetwo stars for each evaluation criterion is the best possible.A= Maximum efficiency at approx. 6L/min <9L B=>9L<12L
WELL (2011)
US, EU, etc.: Regulations and restrictions based on physical quantity measurements
Japan: Evaluation of optimal flow based on industry standards (enacted 2009, voluntary)
Highly reproducible water discharge force standards that preserve amenity are needed (2013)
7
2013 Currently, best-effort; mandatory in 2020
2009
Problems in previous cases
• Most showers in Japan are handheld– Distance between showerhead and body is not fixed
• Excluding load of water droplets on plate
8
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Z905S
Z905SMC
S3950-
82X
S3950-
80X
S31B-80X
S329GB-
80X
TH770C
THC24C
THC10
THY475G
通販A社
通販B社
通販C社
[°]
TO TO
KVK
三栄水栓
13 retail market showerheads (sample)
Pla
te r
evo
luti
on
[d
eg.]
U.S. EPA evaluation testing #1(Watersense)
Water receiving plate
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Source: Japan Valve Manufacturers' Association http://www.j-valve.or.jp/
K Co. S Co.
Sho
wer
A -B
T Co.
-C
-D -E -F
-G
-H -I -J
-K
-L
-M
Testing Maker
9
Studies on physical properties of showers (Japan)
“Experimental Study on the Usability of Residential Hot Water Supply System : Part 2-Showering and Bathing” (Kamata et al.)
“Study on methods of designing shower heads” (Kondo et al.)
“A Study on the Design Requirements of Equipment for Taking a Shower”(Murakawa et al.)
Measurement perpendicular to spray force
Measurement 45° to spray force
Optimal shower flow rate is proportional to the nth power of the total hole area
Need to analyze low-water showerheads implementing various mechanisms
Need to exclude factors affecting load other than shower spray
For men and women in their 20s, showerhead usage appraisal can be determined from optimal flow at chest area and level of satisfaction
16
Mean flow in free bathing experiment: Near optimal chest flow
① ② ⑩
10.5 8.8 7.7
10.5 8.8 7.3
12.9 10.2 8.6
12.0 10.1 7.6
Optimal flow for chest
Optimal flow for head
Showerhead
Optimal flow for full body
Mean flow
in free bathing experiment
Test period
Test location
Subjects
Showerhead Nos. ①, ②, ⑩Temp Laboratory temp.: 25 °C; Water temp.: Freely set by subject
Order of actions As per subject's normal showering behavior
Nov 2012
Univ. of Tokyo, School of Engineering, Bldg. artificial environment laboratory bath unit10 men (20s; same subjects as in optimal flow tests)
Conditions
0.67 0.66 0.72 0.70 0.69 0.59
0.80
0.48 0.48 0.64
0.94
0.57
0.00.20.40.60.81.01.2
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
10.3 8.6
10.2 8.1 7.4
6.0 7.5 7.7 7.7 7.2 6.9
5.5
0
5
10
15
Spray force at optimal flowSpray force can be used as an index for determining optimal flow
Spray force around 0.7 N at optimal flow
For showerheads like ⑧ and ⑨ that add air, optimal flow is below 0.5 N
0.67 0.66 0.72 0.70 0.69 0.59
0.80
0.48 0.48 0.64
0.94
0.57
0.00.20.40.60.81.01.2
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
10.3 8.6
10.2 8.1 7.4
6.0 7.5 7.7 7.7 7.2 6.9
5.5
0
5
10
15
Flo
w [
L/m
in]
0
5
10
15
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
Tota
l sp
ray
forc
e [N
]
*Mean flow values for men and women in their 20s at chest area
0.7 N
Total spray force at optimal flow
Optimal flow & Range of satisfactory flow
1.0
1.2
0.6
0.8
0.2
0.4
017
Max. satisfactory flow (mean)
Min. satisfactory flow (mean)
Optimal Flow (mean)
𝐹 = 𝐶𝑄2
0.46
0.64 0.50
0.77 0.90
1.18
1.01
0.59 0.59
0.88
1.45 1.37
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
8.5
L/分の全吐水力
(計算値
)(N)
0.455
0.643
0.499
0.773
0.903
1.185
1.012
0.585 0.592
0.881
1.445 1.366
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
8.5L
/ 分における全吐水力
[N]
シャワーヘッド①~⑫
No water-savingmechanism (①)
18
Total spray force at 8.5 L/min (15% reduction)Standard B1
Air included in water (⑧⑨)
Standardized using total spray force at flow of 8.5 L/min
B-1 specifies spray force of 0.6 N or higher at 8.5 L/min
B-2 will add supplementary items
Spray force at 8.5 L/min flow
Tota
l sp
ray
forc
e at
8.5
L/m
in [
N]
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0
Overall and by-part satisfactionSatisfaction: Chest < Head
Total satisfaction: Similar to chest satisfaction
19
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
-1.0 -0.5 0.0 0.5 1.0 1.5 2.0
Sati
sfac
tio
n (
ches
t)
Total satisfaction
Sati
sfac
tio
n (
Hea
d)
Total satisfaction
+1.5
+2.0
+0.5
+1.0
-0.5
0.0
-1.0-0.5-1.0 +0.50.0 +1.5+1.0 +2.0
No water-savingmechanism (①)
No water-savingmechanisms (①)
+1.5
+2.0
+0.5
+1.0
-0.5
0.0
-1.0-0.5-1.0 +0.50.0 +1.5+1.0 +2.0
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
Standard B2(Being standardized)
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
0
5
10
15
20
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
32.521.510.50-0.5-1-1.5-2-2.5-3平均値
05
101520
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3
Chest satisfaction, appraisers, and mean values
Head satisfaction is overall high, due to be less sensitive by hair.
Water-saving showerheads show possibility for lowering water use while maintaining satisfaction
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
Num
. re
sponde
nts
Mean
sat
isfa
ctio
n (
chest
)
-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
0
5
10
15
20
1 2 3 4 5 6 7 8 9 10 11 12
-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
0
5
10
15
20
1 2 3 4 5 6 7 8 9 10 11 120
5
10
15
200
5
10
15
20
Num
. re
sponde
nts
+2.0+1.5+1.0+0.5
-1.0-1.5-2.0
0.0-0.5
+2.0+1.5+1.0+0.5
-1.0-1.5-2.0
0.0-0.5
Mean
sat
isfa
ctio
n (
head
)
Chest
Head
Low HighSatisfaction
20
Standard B2(Being standardized)
Mean
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
(10)
(5)
0
5
10
15
20
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
21
Single-hole spray force at optimal flow
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫
Sin
gle-
ho
le s
pra
y fo
rce
at 7
.0L/
min
[N
/ho
le]
0.015
0.020
0.005
0.010
0
Standard B2(Being standardized)
1.5
2.0
0.5
1.0
0
-1.0
-0.5
Single-hole spray force at 7.0L/min
Mea
n s
atis
fact
ion
(C
hes
t)
Single-hole spray forceat 7.0L/min
Mean satisfaction (chest)at optimal flow
Single-hole spray force [N/hole] =Total spray force [N]
Number of holes
Use the total spray force at 7.0L/min
Single-hole spray force of unsatisfied Showerhead (⑥,⑫) tends to be strong
•
•
•
•
22
Summary
・Spray force is proportional to square of flowProportionality constant C is proportional to the reciprocal of the
total hole area・Spray force at optimal flow is approx. 0.7 N・ Flow and satisfaction in actual use can be obtained from chest results
Subject testing
Standard B1 (low-flow spray) conditions
・Total spray force is at least 0.6 N at 8.5 L/min (15% reduction)
Standard B2 (revised low-flow spray) conditions
・Revision expected to use single-hole spray force (under consideration)
23
Future directions
Energy code 2013(Low-flow spray
standards)
201310/1
20144/1
Repealed
Enacted Full enactment
201410/1
20154/1
[Residential]
Pre-revision low energy standards
Revised low energy standards
Standard B-18.5 L/min (15% reduction) or less
(Transitional measures)
Standard B-2 7.0 L/min (30% reduction) or less
Begin operation
Present
Acknowledgements: This study is the result of the activities of the Better Living Foundation's committee for research on further improvements to energy efficiency in residential hot water supply systems. We express our deepest thanks to the committee members and other who helped us with this research.