WEB-BASED SIMULATION TOOL FOR COMPLIANCE WITH 2013 ENERGY EFFICIENCY STANDARD FOR COMMERCIAL BUILDINGS IN JAPAN

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1 WEB-BASED SIMULATION TOOL FOR COMPLIANCE WITH 2013 ENERGY EFFICIENCY STANDARD FOR COMMERCIAL BUILDINGS IN JAPAN Masato Myata 1, Takao Sawach 1, Yasuo Kuwasawa 2, Yasuhro Mk 2 Yoshhko Akamne 1 and Hdek Yamaguch 1 1 Natonal Insttute for Land and Infrastructure Management, Japan 2 Buldng Research Insttute, Japan ABSTRACT The Natonal Insttute of Land and Infrastructure Management (NILIM) and the Buldng Research Insttute (BRI) have developed new methodologes for evaluatng the prmary energy consumpton of commercal buldngs for the buldng energy effcency standards n Japan. In the frst part of ths paper the possblty of applyng smulaton technologes to buldng regulatons are shown. For these smulaton technologes to play an mportant role n promotng complance wth buldng regulatons, t s mportant to consder the understandablty and relablty of the calculaton method, the clarty of the defntons of the smulaton nputs, and the strctness of verson management. In the second part of ths paper, the detals of the methodologes to calculate the prmary energy consumpton are gven and several examples of the applcaton of the calculaton tools to actual buldngs and the comparson results of actual prmary energy consumpton and smulated prmary energy consumpton are shown. INTRODUCTION In Japan, accordng to the buldng energy effcency standard prescrbed n the Law Concernng the Ratonal Use of Energy, buldng constructors should revew ther buldngs energy performance and report the revew results to admnstratve agences before they start buldng. To acheve further energy savngs n buldngs, the Japanese government has decded that complance wth the standard wll be mandatory for all newly bult commercal buldngs and housngs untl As a frst step toward mandatory complance wth the standard, the Japanese government revsed the buldng energy effcency standard for commercal buldngs (Offces, Hotels, Hosptals or clncs, Retal shops, Schools, Restaurants, Theaters and halls, and Factores) n Aprl In the revsed standards, the prmary energy consumpton of buldng equpment s requred as a crteron ndex, n addton to buldng envelope performance (new Permeter Annual Load, PAL*). The Natonal Insttute of Land and Infrastructure Management (NILIM) and the Buldng Research Insttute (BRI) have developed new methodologes for evaluatng the annual heat load n permeter zones (.e. PAL*) and the prmary energy consumpton of ar-condtonng systems, ventlaton systems, lghtng systems, hot water supply systems, and elevators. They have also developed a web-based onlne calculaton tool to help calculate these ndces. The methodologes are expected to be sutable for the mandatory standard. Here, we descrbe the concept of the evaluaton methodologes, the ways n whch web-based calculaton tools are used n the standards, and the detals of the methodologes used to calculate the prmary energy consumpton. APPLICATION OF SIMULATION TECHNOLOGIES FOR TESTING COMPLIANCE WITH BUILDING REGULATIONS Applyng smulaton technologes for testng complance wth mandatory buldng regulatons s a challengng task. The new evaluaton methodologes have been developed accordng to the followng phlosophes: - The calculaton method should be reasonable and easy to understand, so that users can work out what they need to do to ensure that ther buldngs meet the standard. The calculaton tool should have a functon that dsplays not only the outputs (calculaton results) but also the calculaton process. - The calculaton results can be foreseeable to a certan extent, wthout the need to execute the calculaton tool tself, so that revewers can judge the valdty of the calculaton results even f they don t have enough knowledge of the buldng s equpment. We decded to publsh the buldng equpment specfcatons that are used to determne the reference prmary energy consumptons. Ths nformaton helps revewers to understand whether or not the calculaton results are approprate. - The calculaton results should be far, relable, and verfable. We developed the methodologes by usng the results of our nvestgatons of performances

2 Desgn documents Computatonal engne on cloud computng platforms XML fles Calc. results Specfcaton Input Sheet BRI Webste Download Calculaton Results - Excel Sheet - Manual - Interface of the web-based smulaton tool Upload Input the product specfcaton of the buldng equpment to the Excel fle. Fgure 2 Example of nput sheets (n Japanese) Fgure 1 Flow for evaluaton of a buldng s prmary energy consumpton measured n actual buldngs. Because the calculaton tool can estmate realstc energy consumpton, users can compare varous energy-savng technques farly. - The nputs of the calculaton should be defned clearly. The calculaton results should be equal, no matter who uses the calculaton tool to evaluate the buldng. We defned the rules of the nputs clearly, and some of the nputs were lnked to the Japanese Industral Standard (JIS). For example, the coeffcents of performance (COPs) of chllers dffer f the measurement condtons (e.g. chlled water temperature) are dfferent. Therefore, t should be made clear that users need to nput COPs under condtons regulated by JIS B Inputtng data for the calculaton should not requre much tme and effort. Inputs should be made on the bass of the desgn documents (e.g. equpment lsts and specfcatons). Ths also helps revewers to check the nputs of the calculaton easly, because they can compare the desgn documents and the nputs wthout usng extra nformaton. We developed a calculaton tool wth nputs that are made easly by copyng and pastng the nformaton n the equpment lsts and specfcatons of the desgn documents. - The verson of the calculaton tool should be managed strctly. We developed an onlne calculaton tool for managng versons easly. In the case of offlne calculaton tools t s dffcult to control software versons once the calculaton tool has spread worldwde. - The calculaton tool should not depend on the user s PC envronment. We decded to use cloud-computng technologes. By usng cloud computng, users can execute detaled, speedy calculatons regardless of Fgure 3 Interface of the tool (n Japanese) ther PCs performance. Ths can reduce the cost of user support. WEB-BASED CALCULATION TOOL The Web-based onlne calculaton tool for the revsed standard s avalable on BRI s webste ( When buldng constructors buld new commercal buldngs wth a floor area of more than 300 m 2, they must calculate the prmary energy consumpton wth ths tool and report the revew results to admnstratve agences. The standard started operatng n Aprl Fgure 1 shows the procedures used to evaluate the prmary energy consumpton by usng the tool. To calculate prmary energy consumpton, users should nput the specfcatons of the buldng envelope and equpment to a Specfcaton Input Sheet, whch s avalable on BRI s webste as a Mcrosoft Excel fle (Fgure 2). The sheet has a functon for convertng the Excel fle to several CSV fles. When the CSV fles are uploaded to the tool, the results of calculatons of the prmary energy consumpton of the ar-condtonng system, ventlaton system, lghtng system, hot water supply system, and

3 Clmate zone Room type and floor area Database of clmate condtons Assumptons for room use Crteron value for each room type Ar-condtonng system (AC) Hot water supply system (HW) Spec of envelope - Insulatng materal - shadngs etc. Spec of AC - Rated energy consumpton of heat source, etc. Spec of HW - Effcency of heat source, etc. Outdoor ar temperature, etc. Outdoor ar temperature, etc. Internal heat gan Tme for AC HW demand Tme for HW Coolng /Heatng load Performance curve of heat source, etc. Performance curve of heat source, etc. E for AC E for HW Reference energy consumpton Sum Compare Desgned energy consumpton Lghtng System (L) Spec of L - Energy consumpton per unt, etc. Tme for L Coeffcent of energy reducton by control systems E for L Ventlaton system (V) Spec of V - Energy consumpton of a fan, etc. Tme for V Coeffcent of energy reducton by control systems E for V Elevators (EV) Spec of EV - Control method of the EV, etc. Tme for EV Coeffcent of energy reducton by control systems E for EV E for offce automaton equpment Fgure 4 Flow of calculatons of prmary energy consumpton. (AC, ar-condtonng; HW, hot water; L, lghtng; V, ventlaton; EV, elevators) elevators are dsplayed on the tool s nterface (Fgure 3). Gudelnes for the rules for creatng a Specfcaton Input Sheet n accordance wth the buldng desgn documents have been publshed on BRI s webste as a PDF fle. CALCULATION METHOD Fgure 4 shows the flow used to calculate a desgned prmary energy consumpton E d [MJ/year] and the reference prmary energy consumpton E r [MJ/year]. The nput of the calculaton method s shown n the left sde of Fgure 4. In order to calculate E d, users have to nput clmate zone and nformaton of each room (room type, floor area, floor heght, drecton and area of exteror walls and wndows) as well as the buldng envelop materal propertes defnton and the specfcaton of equpment. The rato of E d to E r s defned as the BEI (Buldng Energy Index), as follows: BEI E E (1) d r If the BEI of a buldng s not more than 1.00, the buldng s judged to meet the crtera. E d s calculated by usng specfcatons for the buldng envelope and equpment accordng to the methodologes developed by NILIM and BRI (2013). E d s a summaton of the desgned prmary consumpton of the ar-condtonng system E d, AC, ventlaton system E dv,, lghtng system E dl,, hot water supply system E d, HW, elevators E d, EV, and others E OT. E OT s assumed to be the energy consumed by offce automaton equpment, and the value s determned n the standard. If a buldng has photovoltac power generaton systems or cogeneraton systems, the savngs n energy resultng from the systems,.e. E d, EF, where EF = effcent, can be taken nto account as follows: E E E E E d d, AC d, V d, L d, HW E E E d, EV OT d, EF (2) The reference prmary energy consumpton E r s calculated as follows. The value of E OT s the same as that of E OT n Equaton (2). The standard consders reference prmary energy values and not a reference buldng wth predefned values as wth Baselne Buldng Method n ASHRAE Standard E E E E E r r, AC r, V r, L r, HW N r,* r, per,*, j j j1 E r, EV E OT (3) E E A (4) E r,* : Reference prmary energy consumpton of equpment tem * [MJ/year]

4 Table 1 Reference prmary energy consumptons, E r,per,,j, descrbed n the standard Table 2 Examples of assumptons of room use E r, per,*, j : Reference prmary energy consumpton of equpment tem * for room j [MJ/m 2 /year] A j : Floor area of room j [m 2 ] (* AC: ar-condtonng system; V: ventlaton system; L: lghtng system; HW: hot water supply system; EV: elevators) E r, per,*, j s defned n the standard for 8 clmate areas and for 201 room types. Table 1 gves some examples of E r, per,*, j. ROOM TYPES AND STANDARDIZED USER CONDITIONS We classfed the room use patterns n commercal buldngs (e.g. ar-condtonng system operaton tme, amount and schedule of heatng from applances and lghtng, volume of fresh ar ntake, etc.) nto 201 types on the bass of the results of nvestgatons n actual buldngs. We then determned standardzed user condtons for each room type. Table 2 gves some examples of assumptons for room use. CALCULATION METHODOLOGIES Ar-condtonng systems Ths secton gves a bref explanaton of the methodologes used to calculate the desgned prmary energy consumpton of ar-condtonng systems. Fgure 5 shows the flow used to calculate the prmary energy consumpton of ar-condtonng systems. Ths flow conssts of two parts: room heat-load calculaton and energy calculaton. In the heat load calculaton, the daly heat loads of each room are calculated as follows: Q ( t) a Q ( t) b (5) rl, j j rg, j j QrL, j () t : Daly room heat load of room j [MJ/m 2 /day] Q, () t : Daly heat gan of room j [MJ/m 2 /day] rg j As the daly heat gan QrG, j the followng two knds of heat gan are taken nto account: a) Heat gan through exteror walls and wndows as a result of the temperature dfference between the ndoor ar n [ o C] and the outdoor ar out [ o C]: N j Q U A (6) rg, T, j T, j, n T, j, n out n n1 Ths calculaton method does not take the effect of thermal brdges nto account. b) Heat gan through wndows as a result of solar radaton I sr [W/m 2 ]: N j Q A I (7) rg, S, j S, j, n S, j, n sr n1 Coeffcents a j and b j n Equaton (5) are coeffcents for convertng statc heat gan to dynamc heat load. These values are determned on the bass of an analyss usng the dynamc thermal load calculaton program newhasp. We made regresson equatons from the relatonshp between dynamc thermal load calculated by usng newhasp and the statc heat gans Q rg, T, j and Q rg, S, j as shown n Fgure 6, and determned the coeffcents a j and b j n Equaton (5). They are dependent on the zone, room use, and season and on the use of arcondtonng the prevous day

5 Clmate zone Room type, Floor area Database of clmate data Database of standard schedules Temperature, humdty solar radaton Input: buldng envelope - Floor area of rooms, outdoor wall area, wndow area, drecton of walls and wndows, shadng factor, etc. Load condtons Calculaton of daly heat gan Estmaton of daly heat load a) Heat load calculaton Coeffcents for load calculaton Coeffcents Performance curves of heat source equpment Performance curves Input: equpment - Ar-handlng unts capacty, supply ar volume, energy consumpton, control system (CAV or VAV), economzer - Secondary pumps rated flow rate, energy consumpton, control system (CWV or VWV) - Heat source equpment s capacty, energy consumpton Daly room heat load Appearance frequency of heat load Heat load of pumps Calculaton of energy of ar-handlng unts Heat load of heat source Calculaton of energy of secondary pumps Calculaton of energy of heat source equpment Energy of ar-handlng unts Energy of secondary pumps Energy of heat source equpment b) Energy calculaton Fgure 5 Flow of calculatons of prmary energy consumpton of an ar-condtonng system (CAV, Constant ar volume; VAV, Varable ar volume; CWV, Constant water volume; VWV, Varable water volume, AHU, Ar-handlng unt) In the energy calculaton, ar-condtonng loads are calculated by usng QrL, j () t and the outdoor ar load. Ths calculaton method does not take the losses due to dstrbuton and hand-over nto account. The outdoor ar load changes f the system has ar-toar total heat exchangers or economzers. The prmary energy consumpton of the ar-condtonng system E d, AC s calculated as follows: E E E E (8) d, AC d, AC, AHU d, AC, PUMP d, AC, REF Fgure 6 Relatonshp between dynamc thermal load calculated by usng newhasp and statc heat gan E d, AC, AHU : Energy consumpton of ar-handlng unts [MJ/year] E d, AC, PUMP : Energy consumpton of secondary pumps [MJ/year] E d, AC, REF : Energy consumpton of heat source equpment [MJ/year] The concept used to calculate E d, AC, AHU, E d, AC, PUMP, and E d, AC, REF s shown n Fgure 7. For each tem of ar-handlng unt (AHU), pump, and heat source equpment, a dstrbuton for the appearance frequency of the ar-condtonng load s

6 Fgure 7 Concept for calculatng energy consumpton Table 3 Example of calculaton of energy consumpton of ar-handlng unts (Assumptons: Coolng/heatng capacty kw; supply fan 15.0 kw; return fan 1.5 kw; varable ar volume control system; mnmum damper openng 40%) Table 4 Example of a heat load matrx for heat source equpment generated and the appearance tme of each of the part load rato (PLR) bands s calculated (Table 3). The energy consumpton of the equpment on each PLR band s calculated by multplyng the appearance of the load and the energy nput, whch dffers dependng on the control systems ntroduced. If an AHU system has a CAV (constant ar volume) control system, the energy consumpton of all PLR bands wll be constant (rated power consumpton). If an AHU system has a VAV (varable ar volume) control system, the energy consumpton wll change wth the PLR of the equpment. Table 3 shows an example of the calculaton. - In a part load rato of 0.6 to 0.7, the Appearance of load (20 h) can be obtaned from the results of the heat load calculaton. - Energy nput = Rated power consumpton (15 kw kw) * average load factor = 6.97 kw. If a VAV control system s used, the amount of power consumed s dependent on the load factor (the square of the average load factor). - Amount of power consumed = 20h * 6.97 kw/1000 = 0.14 MWh. - Annual amount of power consumed s the sum of power consumed n all load factor ranges (5.90 MWh). As wth heat source equpment, the appearance frequency of the ar-condtonng loads s generated accordng to not only the PLR but also the outdoor ar temperature (Table 4). Ventlaton systems The desgned prmary energy consumpton of ventlaton systems E dv, s calculated as follows. N 6 d, V 10 v, v, v, prme 1 E E T F f (9) E v, EVm, (10) m E v, : Power consumpton of the blower [W]

7 T v, : Operatng hours of the blower [h] F v, : Control-system-dependent coeffcent of the blower [-] f prme : Prmary energy factor for electrcty [kj/kwh] E Vm, : Rated power of the blower motor [-] : Motor effcency (0.75) [-] m The operatng hours T v, j are specfed for each room use, dependng on the standardzed room use condtons. A Control-system-dependent coeffcent F v, j s defned as follows; - Use of a hgh-effcency motor 0.95 f Yes - Use of an nverter 0.6 f Yes - Use of blower flow rate control 0.6 for CO/CO 2 concentraton control 0.7 for temperature control Lghtng systems The desgned prmary energy consumpton of lghtng systems E dl, s calculated as follows. N 6 d, L 10 L, L, L, L, prme 1 E E T F C f (11) E L, : Power consumpton of lghtng equpment [W] T L, : Lghtng hours [h] F : Control-system-dependent coeffcent [-] L, C : Room-shape-dependent coeffcent [-] L, The lghtng hours T L, are specfed for each room use, dependng on the standardzed room use condtons. A room-shape-dependent coeffcent C L, s for correcton wth a room ndex (=L*D / [(L+D)*H], where L: wdth of the room, D: depth of the room, H: elevaton of the equpment) to mtgate the dsadvantages of a room wth a low room ndex. A control-system-dependent coeffcent F L, s defned for each control system shown n the followng. - Occupancy-detecton control wth a moton sensor - Tme-schedule control - Intal-brghtness-correcton control - Daylght-dependent lght control wth a brghtness sensor - Automatc ON/OFF control wth a brghtness sensor - Brghtness control/lght control wth a brghtness sensor Hot water supply systems The desgned prmary energy consumpton of hot water supply systems E d, HW s calculated as follows. E d, HW N 3 QWr, CW QWp, 10 (13) 1 W, 365 Q c V Q Wr, w w Wtap Wn, d W, d, W, solor, d, d 1 Q Wr, W : Annual hot-water-supply load [kj] C : Correcton factor [-] Q : Annual ppe heat loss [kj] Wp, : Heat-source operatonal effcency [-] W, V W, d, Wtap : Hot water use [L/day] (14) : Hot-water-supply temperature (43 o C) [ o C] : Water-supply temperature [ o C] Wn, d Q W, solor, d, : Use of heat from the solar water heatng system [kj/day] Hot water use V W, d, s specfed for each room use, dependng on the standardzed room use condtons. The effect of hot-water-savng equpment s reflected n ths. The water-supply temperature Wn, d has been calculated for each zone as a functon of outdoor temperature. Annual ppe heat loss Q Wp, s calculated as follows. 365 Q 3.6 L k T L Wp, W, W, Wp amb, d W, d, d 1 W, (15) Vsw, Ixsw (16) 1000 L W, : Vrtual ppe length [m] k : Ppe heat-loss coeffcent [W/(m. K)] W, : Crculatng water temperature (60 o C) [ o C] Wp : Ppe ambent temperature [ o C] amb, d T : Operatonal hours [h] W, d, V : Average daly hot water use [L/day] sw, Ix : Assumed Ix value (7.0) [-] sw Ppe heat-loss coeffcent k W, s determned from the ppe sze and the nsulaton specfcatons. The ppe ambent temperature amb, d s the average of the outdoor temperature and the room temperature

8 Annual Prmary Energy Consumpton [MJ/m 2 ] L W, s vrtual ppe length whch s not equal to actual ppe length. Because the work of readng the ppe length of a central hot-water-supply system s very complcated, tme-consumng and dffcult to verfy the accuracy n short tme nspecton by the admnstratve agences, we desded that ths work has been elmnated. The vrtual ppe length s estmated from the daly hot water use as Equaton (16). A correcton factor C W n Equaton (13) s 2.5. The value has been determned so that prmary energy consumpton by ths calculaton method (the above formula) and by a detal smulaton are equal. Elevators The desgned prmary energy consumpton of elevators E d, EV s calculated as follows. LEV, VEV, CEV, TEV, Ed, EV (17) 860 L EV, : Loaded mass [kg] V : Rated speed [m/mn] EV, C EV, : Speed-control-system-dependent coeffcent [-] T EV, : Operatonal hours [h] The annual number of lghtng hours for each room use under the standardzed room use condtons s used as the number of operatonal hours T EV,. VERIFICATION In order to verfy the accuracy of the developed calculaton method, we appled the calculaton method to fve actual buldngs (Offce, Restaurant, Hotel, Hosptal and School, whch are located n Tokyo, Japan) and compared the calculated energy consumpton wth the actual energy consumpton measured n these buldngs n Aprl 2013 to March The comparson results are shown n Fgure 8. Though the dfference of the restaurant s energy consumpton s bgger because the actual user condtons are qute dfferent from the standardzed user condtons assumed n the standard, we consder that the developed calculaton method can estmate the annual prmary energy consumpton of the buldngs wth a certan degree of accuracy. CONCLUSION Here, we have shown the possblty of applyng smulaton technologes to buldng regulatons. For these smulaton technologes to play an mportant 6,000 5,000 4,000 3,000 2,000 1,000 Ar-condtonng Ventlaton Lghtng OA equpment Lghtng + OA Hot water supply Elevators Unknown 0 Fgure 8 Comparson results between actual energy consumpton and calculated energy consumpton role n promotng complance wth buldng regulatons, t s mportant to consder the understandablty and relablty of the algorthm, the clarty of the defntons of the smulaton nputs, and the strctness of verson management. REFERENCES Offce Restaurant Hotel Hosptal School Evans M, Shu B, Takag T.: Country Report on Buldng Energy Codes n Japan, The Unted States of Amerca:PNNL, Aprl Hsash Mura: Energy Effcency Standard, Zero Energy House Incentve and Other Energy Conservaton Measures for Resdental House n Japan, APEC Workshop on Net Zero Energy Buldng & Communty, October 2014 IEA: Energy Technology Perspectves 2012 IEA EBC Programme: Strategc Plan , October 2013 IEA: Transton to Sustanable Buldngs, Strateges and Opportuntes to 2050, 2013 Jens Laustsen. Energy Effcency Requrements n Buldng Codes, Energy Effcency Polces for New Buldng, Internatonal Energy Agency, 2008 Masato Myata: New Energy Standard for Commercal Buldngs n Japan and ts applcaton to NZEB desgn. APEC Workshop on Net Zero Energy Buldng & Communty, October 2014 NILIM and BRI 2013, Legal nterpretaton of the buldng energy effcency standards prescrbed n the Law Concernng the Ratonal Use of Energy revsed n Aprl Natonal Insttute of Land and Infrastructure Management and Buldng Research Insttute, Tokyo, Japan