Showerhead amenities for reduced energy use and standardization of hot water conservation

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

Energy consumption trends in Japan Revised energy standards, resulting from the Great East Japan Earthquake 18 16 14 12 (10 18 J) Drastic enhancement of energy-saving and power-saving measures x2.4 from increased GDP, 1973 2011 Transport Trillion yen ( 兆円 2005 年価格 ) 600.0 500.0 23.3% 400.0 Increase (Fiscal 1973 2011) x1.9 1016.4% 9.2% 8 8.9% Business Residential 19.6% 300.0 14.2% x2.8 x2.4 6 200.0 x2.1 465.5% 2 Industrial 42.8% 100.0 x0.9 0 73 75 80 85 90 95 00 05 11 Fisical year Source: Energy Whitepaper 2013, METI 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 0.0 ( 年度 ) 2

Residential energy consumption in Japan Energy-saving measures are needed in the civilian sector From regulation of only residential insulation to primary energy regulation Residential energy consumption breakdown Lighting, etc. Hot water 34.7% 28.3% Fiscal 2011 38,358 10 6 Cooling J/home 2.2% Kitchen 8.1% Heating 28.3% Source: Energy Whitepaper 2013, Agency for Natural Resources and Energy Hot water consumption, 4-member family (n=47) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Non-bath faucet 108L Bath 120L Shower 149L Source: Nakahama et al. (2009) Measurement of bathtub water consumption for bathing (Part 4), Proceedings of the Air Conditioning and Sanitary Engineers Annual Meeting 3

Residential energy reduction attempts in Japan 1980 (Old) energy conservation standards 1992 New energy-saving standards 1999 Next-generation energy-saving standard 2006 Revision 2009 2013 Revision Oil shock Rational use of energy resources 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 Amended energy conservation standards Strengthened residential standards for primary energy consumption in addition to envelope thermal performance Hot water / AC / Ventilation / Lighting / Elevators Meeting standards requires High-efficiency water heaters High-insulation bathtubs Solar water heaters Installation/replacement of lowuse hot water equipment High energy-saving effects for construction costs; rapid adoption expected Water-saving standards A1 (manual) / C1 (water priority spout) Reconsideration of standard B1(low-flow spout) New consideration of standard B2 (revised low-flow spout) Currently, best-effort; mandatory in 2020 4

Low-flow water discharge standards in Japan (2009 measurement method) Voluntary amenity standards by the Japanese Valve Manufacturers' Association Quantitative metrics under consideration for standardization Definition Flow Less Flow rate [L/min] More Min. usable flow Min. satisfactory flow Optimal flow Max. satisfactory flow Max. usable flow Flow measurement method Reduction Conditions Test conditions Shower sprayed onto chest area Reason: Spraying on face is likely to result in lower flow than in typical use Subject conditions (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 Optimum flow rate is the average of (1), (4), and (7) 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. Avg. optimal flow as measured by monitor Current typical flow rate (10 L/min) Reduction ratio = (1 ) x 100 At least 10 subjects, approx. equal division of sexes Reason: To prevent differences in spray amounts due to sex Source: Japan Valve Manufacturers' Association http://www.j-valve.or.jp/ 5

Japanese shower standards Type and effect Source: Japan Valve Manufacturers' Association http://www.j-valve.or.jp/ 6 Standard Definition Standard of Judgment for Residential Construction Clients (2009) Items fulfilling reduction standards according to the monitoring method established by the Japan Valve Manufacturers Association Low-energy standards for homes and buildings Energy code 2013 Items meeting standards for low-water construction Certification Manufacturer measurement and evaluation JIS measurement and certification Manual stoppage (Type A) Water is easily stopped by manual operation 20% reduction Push button faucet Switch shower Switch Low-flow faucet (Type B) Optimal flow of 8.5L/min or less 15% reduction Spray shower (Low-Flow) Low-flow faucet standards currently being established Combined 32% reduction Currently being established

International shower standards Japan Mandatory Voluntary Common: FLOW RATE OTHER REQUIREMENTS STANDARD 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 USA Mandatory Common: Max. 9.5 L/min(2.5 gpm) at 550 kpa High efficiency: Max. 7.6 L/min (2.0 gpm) Min. 75% of max. at 550 kpa 75% of max. at 410 kpa EU Japan: Evaluation of optimal flow based on industry standards (enacted 2009, voluntary) US, EU, etc.: Regulations and restrictions based on physical quantity measurements Highly reproducible water discharge force standards that preserve amenity are needed (2013) 2009 Voluntary 60% of max. at 140 kpa Max. 7.6 L/min (2.0 gpm) Min. 75% of max. at 550 kpa 75% of max. at 310 kpa 60% of max. at 140 kpa High efficiency (prerequisite): 7.6 L/min (2.0 gpm) Very high efficiency (2pt): 6.6L/min (1.75 gpm) Mandatory Water run through apparatus and flow rate calculated Type 1: (0,3 + 0,02) MPa (3 + 0,2) bar Type 2: (0,01 + 0,005) MPa (0,1 + 0,05) bar Record flow rate Q after stabilization 2013 Currently, best-effort; mandatory in 2020 Voluntary Min. flow rate: 6 L/min; max. flow rate: 12 L/min. A and B Rating two criteria: volume and temperature two stars for each evaluation criterion is the best possible. A= Maximum efficiency at approx. 6L/min <9L B=>9L<12L Effectiveness and comfort Optimum pressure calculated Spray force: Min. 0.56 N (2.0 oz) @ 140 kpa Spray coverage: 75% (φ50~100 mm) 25% (φ50~150 mm) Thermal shock test Leakage test Mechanical strength test Rotary connection test Japan Valve Manufacturers Association ANSI/ASME A112.18.1 EPA WaterSense LEED (2009 v3) EN1112 (2008) WELL (2011) 7

Problems in previous cases Most showers in Japan are handheld Distance between showerhead and body is not fixed Shower A - B - C - D - E - F - G - H - I - J - K - L - M Plate revolution [deg.] Excluding load of water droplets on plate Water receiving plate U.S. EPA evaluation testing #1 (Watersense) [ ] 6.0 5.0 4.0 3.0 2.0 1.0 0.0 Z905S Z905SM C S3950-82X Testing Maker T Co. K Co. S Co. S3950-80X S31B-80X S329G B- 80X 13 retail market showerheads (sample) Source: Japan Valve Manufacturers' Association http://www.j-valve.or.jp/ TH770C THC 24C THC 10 THY475G 通販 A 社 通販 B 社 通販 C 社 8

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.) Optimal shower flow rate is proportional to the nth power of the total hole area Q T Optimum flow Q T = CA n C,n Experimental constants A Total hole area Need to analyze low-water showerheads implementing various mechanisms A Study on the Design Requirements of Equipment for Taking a Shower (Murakawa et al.) Measurement perpendicular to spray force Study on methods of designing shower heads (Kondo et al.) Measurement 45 to spray force Need to exclude factors affecting load other than shower spray 9

Spray force test conditions (current draft) Spray Horizontal direction Suppress influence of water load Receiving plate Dimensions: 200 200 mm, t = 3 mm Material: Acrylic Spray force measurement device Rated capacity: 20 N Resolution: 0.01N Precision: ±2% FS Sampling period: 50ms Spray distance (to receiving plate) 150±15mm Spray adhesion point (central) Permissible range (a): 0±20mm Spray angle Permissible range (b): 0±15 Flow rate 7.0, 8.5, 10L/min Permissible range: ±0.2L/min Spray adhesion point (central) (a) Spray angle (b) 10

Showerheads used in the experiment 27.0 1 : No water-saving mechanism (Typical example of showerheads currently in use) 2~12:Commercially available water-saving showerheads 8,9: 10 : Air added to hot water, increasing volume Built-in impeller releases water intermittently Showerhead シャワー番号 1 2 3 4 5 6 Water dispersion 散水板外観 plate 18.0 26.6 18.9 26.5 18.0 19.5 Manufacturer-stated メーカー表示最適流量 optimal [L/m flow in] Showerhead Showerhead シャワー番号 10.5 8.5 8.3 7.8 7.0 6.8 7 8 9 10 11 12 34 Water 散水板外観 dispersion plate Manufacturer-stated メーカー表示最適流量 optimal [L/m flow in] 12.2 26.1 29.6 6.5 6.5 6.2 5.8 6.0 Unknown 不明 Manufacturer-stated optimal flow: Optimal flow results based on Standard of Judgment for Residential Construction Clients in 2009(mean of 3 companies). 12.9 25 18 11

Total spray force F [N] Proportionality constant C Relation between spray force and flow Measuring spray force at 3.0, 5.0, 6.5, 8.5, 10, 14 L/min Spray force proportional to square of flow rate Proportionality constant C is proportional to the inverse of the total hole area By knowing proportionality constant C, the spray force at a given flow can be calculated 4.0 3.5 3.0 3.0 2.5 2.0 1.5 F = F=CQ CQ 2 F: 全吐水力 (N) Q= 流量 (L/min) 1 2 3 4 5 6 7 8 9 10 11 12 0.025 0.020 0.015 0.010 C = ρ 2A R 2 =0.933 ρ water density Water temp: 40 1.0 0.5 No water-saving mechanism(1) 0.00 0 5 10 15 20 Water flow rate Q [L/min] 0.005 0.000 0 10 20 30 40 50 60 0 No water-saving mechanism(1) 10 20 30 40 50 60 Total hole area A [ mm2 ] 12

1848 Finding optimal flow (subject experiment) Test period Test location Subjects Conditions Oct Nov 2012 Univ. of Tokyo, School of Engineering, Bldg. artificial environment laboratory bath unit 10 men (20s), 10 women (20s), 10 men (50s); 30 people in total Men and women (20s): Nos. 1 12 Showerhead Men (50s): Nos. 1, 2, 6, 10 Temp. Laboratory temp: 25 C ; Water temp: Freely set by subject Posture Sitting with showerhead handheld Body part Parameter Item Definition Max. satisfactory flow Upper limit of flow allowing comfortable use Flow Optimal flow Ideal flow level Chest Min. satisfactory flow Lower limit of flow allowing comfortable use Head -3-2 -1 0 +1 +2 +3 Entire Combined body Satisfaction Very uncomfortable Uncomfortable Slightly Slightly Neutral uncomfortable comfortable Comfortable Very comfortable 4 showerheads Artificial environment lab. bath unit (25 ) Data logger Flow adjustment valve Temp. adjustment valve Instantaneous gas water heaters (60 ) Hot water pipe Showerhead 4 Bathing Room 1700 Valve Dressing Room (25 ) 3100 1400 Data logger 13

12.9 11.8 14.3 12.3 10.2 10.1 11.5 10.2 11.9 11.7 11.8 10.2 9.6 9.9 9.4 8.8 9.1 7.7 6.9 9.5 7.3 9.3 8.4 8.9 9.6 9.0 9.3 9.4 8.5 8.9 8.6 8.0 9.9 8.3 8.1 6.9 7.5 7.3 6.8 7.0 Optimal flow [L/min] 10.5 10.1 12.1 10.3 8.8 8.4 10.6 8.6 10.3 10.2 10.2 7.8 8.3 8.1 7.5 7.4 7.4 6.1 5.9 8.3 6.0 7.2 7.9 7.5 7.8 7.6 7.7 7.7 7.6 7.7 7.3 7.2 8.4 7.2 7.3 6.4 6.9 5.5 5.4 Optimal flow [L/min] 5.5 Optimal flow results by showerhead 20 20 18 18 16 16 14 14 12 12 10 10 88 66 44 22 00 20 20 18 18 16 16 14 14 12 12 10 10 8 8 6 6 4 4 2 2 0 0 Chest 20 代男性平均 (N=10) 20 代女性平均 (N=10) 50 代男性平均 (N=10) 20 代男女平均 1 20 代男性平均 2 3 (N=10) 4 20 代女性平均 5 6 (N=10) 7 8 9 10 11 12 50 代男性平均 (N=10) 20 代男女平均 Head Men (20s, N=10) Women (20s, N=10) Men (50s, N=10) Mean Showerhead 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 14 Showerhead Ave.+σ Ave.-σ σ: Standard deviation AVE+σ AVE-σ σ: 標準偏差

最適流量 [L/min] Optimal flow [L/min] Optimal flow: Averages by type 最適流量 [L/min] Optimal flow [L/min] Optimal flow [L/min] 15 Men and Women (20s) 20 20 20 Shower Mean of 1 12 20 20 Men in 20s and 50s Shower Mean of 12610 20 20 By body part (head/chest/entire body) *Finding optimal flow for washing the entire body 15 15 10 10 5 5 15 10 5 最適流量 [L/min] 8.7 8.5 8.7 8.5 9.1 15 15 10 10 5 5 10.9 9.1 10.9 8.7 8.5 15 15 10 10 5 5 9.1 10.9 7.7 9.2 8.9 0 0 0 男性 Men (20s) 代 Women 女性男性 20 (20s) 代代女性男性 20 代男性 Men 男性 50 (20s) 代代 Men 男性 (50s) 代 Chest Head *Entire Body Little difference Men(20s)<Men(50s) 0 0 男性 20 代女性 20 代 0 0 男性 20 代男性 50 代 胸頭全身 Chest<Head

Free bathing experiment and comparison Optimal flow [L/min] Test period Test location Subjects Conditions Nov 2012 Univ. of Tokyo, School of Engineering, Bldg. artificial environment laboratory bath unit 10 men (20s; same subjects as in optimal flow tests) Showerhead Nos. 1, 2, 10 Temp Laboratory temp.: 25 C; Water temp.: Freely set by subject Order of actions As per subject's normal showering behavior 14 14 13 13 12 12 11 11 10 10 99 Chest 88 77 66 6 7 8 9 10 10 11 11 12 12 13 13 14 14 Mean flow in free bathing experiment [L/min] Showerhead Mean flow in free bathing experiment Optimal flow for chest Optimal flow for head Optimal flow for full body 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 Mean flow in free bathing experiment: Near optimal chest flow For men and women in their 20s, showerhead usage appraisal can be determined from optimal flow at chest area and level of satisfaction 16

Total spray force [N] Spray force at optimal flow Spray 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 15 15 10 10 10 5 5 Flow [L/min]15 0 1.20 1.0 1.2 1.2 0.8 1.0 1.0 0.6 0.8 0.8 0.4 0.6 0.6 0.2 0.4 0.4 0.2 0.2 0.0 0.0 0 Optimal flow & Range of satisfactory flow 10.3 10.3 8.6 8.6 10.2 10.2 8.1 8.1 7.4 7.4 *Mean flow values for men and women in their 20s at chest area Total spray force at optimal flow 0.67 0.66 0.72 0.70 0.69 0.67 0.66 0.72 0.70 0.69 0.7 N 6.0 6.0 F = CQ 2 0.59 0.59 7.5 7.7 7.5 7.7 7.7 7.7 7.2 7.2 6.9 6.9 0.80 0.80 0.48 0.48 0.48 0.48 Max. satisfactory flow (mean) Optimal Flow (mean) Min. satisfactory flow (mean) 0.64 0.64 0.94 0.94 0.57 0.57 1 2 3 4 5 6 7 8 9 10 11 12 5.5 5.5 17

8.5L/ 分における全吐水力 [N] Total spray force at 8.5 L/min [N] Total spray force at 8.5 L/min (15% reduction) Standard B1 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 1.6 1.4 1.2 1.0 0.8 0.6 Spray force at 8.5 L/min flow 0.455 0.643 0.499 0.903 0.773 1.185 1.012 0.585 0.592 0.881 1.445 1.366 0.4 0.2 0.0 No water-saving mechanism (1) Air included in water (89) 1 2 3 4 5 6 7 8 9 10 11 12 18

Satisfaction (chest) Satisfaction (Head) Overall and by-part satisfaction Satisfaction: Chest < Head Standard B2 (Being standardized) Total satisfaction: Similar to chest satisfaction +2.0 +1.5 1 2 3 4 5 6 7 8 9 10 11 12 +2.0 +1.5 No water-saving mechanisms (1) +1.0 +0.5 0.0 0.0-0.5-0.5 No water-saving mechanism (1) -1.0-1.0-1.0-0.5 0.0 +0.5 +1.0 +1.5 +2.0-1.0-0.5 0.0 0.5 1.0 1.5 2.0 Total satisfaction +1.0 +0.5 0.0 0.0-0.5-1.0-1.0-0.5 0.0 +0.5 +1.0 +1.5 +2.0-1.0-0.5 0.0 0.5 1.0 1.5 2.0 19 Total satisfaction

Num. respondents Mean satisfaction (head) Num. respondents Mean satisfaction (chest) Head20 15 10 5 0 15 0-2 -3-2.5-2 -1.5 1 2-1 3-0.5 4 50 60.57 81 91.5 10 211 122.5 3 20 +2.0 2.00 +1.5 1.50 15 +1.0 1.00 +0.5 0.50 10 0.00-0.50 55-1.00-1.50 0-2.00 20 0 1 2 3 4 5 6 7 8 9 10 11 12 +2.0 2.00 +1.5 1.50 15 +1.0 1.00 +0.5 0.50 10 1 2 3 4 5 6 7 8 9 10 11 12 0.00-0.50 55-1.00-1.50 00-2.00 11 22 33 44 55 66 77 88 99 1010 1111 1212 1-1.5 1.5 1 0.5 0-0.5-1 -1.5-2 -2.5-3 平均値 Standard B2 Chest satisfaction, appraisers, and mean values 0.5 (Being standardized) 10 0 Head satisfaction is overall high, due to be less sensitive by hair. -0.5 Water-saving showerheads 5 show possibility for lowering water use while -1 maintaining satisfaction Chest Low Satisfaction High Mean 20

Single-hole spray force at 7.0L/min [N/hole] Mean satisfaction (Chest) 21 Single-hole spray force 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 Standard B2 (Being standardized) Single-hole spray force of unsatisfied Showerhead (6,12) tends to be strong 0.020 0.015 0.010 5 0.005 0 (5) (10) Single-hole spray force at 7.0L/min Single-hole spray force at 7.0L/min Mean satisfaction (chest) at optimal flow 1 2 3 4 5 6 7 8 9 10 11 12 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 0.0 0-0.5-1.0

22 Summary Subject testing Spray force is proportional to square of flow Proportionality 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 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)

Future directions [Residential] Pre-revision low energy standards Revised low energy standards Announced 2013 2014 10/1 1/1 Present Repealed Enacted 2014 4/1 2014 10/1 (Transitional measures) 2015 4/1 Full enactment Energy code 2013 (Low-flow spray standards) Begin operation Announced Announced Standard B-1 8.5 L/min (15% reduction) or less Begin operation Use fixed-flow valves Standard B-2 Under Planning 7.0 L/min (30% reduction) or less 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. 23

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吐水力試験各規定の理由 25 吐水方向 吐水距離 受水板 項目規定 ( 案 ) 理由 プッシュプルゲージ 測定のタイミング 横向き ( 受水板と散水板が平行になるようにする ) 150mm ( 受水板から散水板まで ) 200mm t=3 材質 : アクリル板 最大 20N ±0.2%F.S. 安定範囲のピーク値 下向きにすると 受水板に水が溜まるため 荷重に影響が出る恐れがある また上向きにすると 受水板にあたった水が散水板に滴下してシャワーの勢いに影響を与える恐れがある 吐水距離 100mm を超えたあたりから荷重値が安定するため シャワーの流線を全て受けることができる大きさ ( 吐水距離 150mm 位置でのシャワー範囲を想定 ) 測定器の精度によるバラツキをなくすため

吐水力測定時の誤差要因検証結果 1 距離と荷重の関係 荷重 [N] 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 距離と荷重の関係 ( 流量別 ) 50 100 150 200 250 300 距離 [mm] 10.0l/ 分 8.5l/ 分 6.5l/ 分 3 着水点のズレと荷重の関係 荷重 [N] 着水点ズレと荷重の関係 ( 流量別 ) 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 6.5l/ 分 8.5l/ 分 10.0l/ 分 中心 (±0) オフセット (+40mm) 2 流量と荷重の関係 荷重 [N] 0.9 0.8 0.7 0.6 0.5 0.4 0.3 流量と荷重の関係 ( 距離別 ) 50mm 100mm 200mm 300mm 4 吐水角度のズレと荷重の関係 荷重 [N] 吐水角度のズレと荷重の関係 ( 流量別 ) 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.2 6 7 8 9 10 11 流量 [l/ 分 ] 0.0 6.5l/ 分 8.5l/ 分 10.0l/ 分 中心 (±0) 15 度 30 度 26