Ecolibrium. The sculpture and the scholars HVAC in a unique space. THE OFFICIAL JOURNAL OF AIRAH JUNE 2015 VOLUME 14.5

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1 THE OFFICIAL JOURNAL OF AIRAH JUNE 2015 VOLUME 14.5 Ecolibrium The sculpture and the scholars HVAC in a unique space. PRINT POST APPROVAL NUMBER PP352532/00001

2 PEER-REVIEWED TECHNICAL PAPERS Recent development of currentclimate data for load estimation and design optimisation Part 2 Validating the updated ACDB-2011, and distillation of ASHRAE-style design temperatures Eric Laurentius Peterson, M.AIRAH * ¹ and J. Ben Liley ² *Corresponding author: e.peterson@uq.edu.au ¹ School of Civil Engineering, The University of Queensland, St Lucia, Queensland ² National Institute for Water and Atmospheric Research, Lauder, New Zealand INTRODUCTION This article extends on Part 1 (background and methods) published in Ecolibrium May 2015, pages There was a key to relevant acronyms and resulting figures showing the close correlation of the ASHRAE 2013 Fundamentals with ASHRAElike 0.4% design conditions extracted from NatHERS 2012 Australian Climate Data Bank developed by NIWA with assistance of UQ (ACDB 2011). Figure 1 (p.48, May issue of Ecolibrium) presented the especially close fit of ASHRAE-like design data presented at the URL Figure 2 (p.48, May issue of Ecolibrium) presented interesting correlations of the 35th highest dry-bulb of TMY2 files drawn from the 29 stations of the original ACDB established by the CSIRO (1983). In this follow-on paper we start by presenting two new figures to illustrate how the ACDB 2011 has included hourly solar radiation since the year Solar radiation was the major factor in selecting months from the ACDB for TMY2A files available at uq.id.au/e.peterson under EPW. Figure 1 hereby illustrates one hour of the more than 20 years of satellite observations covering over 330,000 pixels. Figure 2 presents how the data was checked at 80 particular locations, such as Melbourne International Airport at Tullamarine. Additional figures presented in this paper make psychrometric comparisons of results near the Sydney Regional Office of the Bureau of Meteorology (BoM), while Table 2 compares previously published DA9 design conditions for capital cities with those published by ASHRAE Beware that DA9 Option 1 and Option 2 design temperature published in DA19 (1995) and in the 2014 AIRAH Handbook are for the period ending 1988 and lower than new AIRAH-like design dry-bulb (design DB) temperatures that the authors have determined based upon ACDB 2011 and summarised in Table 1 below. Location Summary Option 1 Dry summer (design DB/coinc WB) Option 2 Wet summer (coinc DB/design WB) e.peterson/new33/ SY 17 Sydney RO 31.9/ / AD 16 Adelaide 38.0/ / ME 21 Melbourne RO 35.5/ / BR 10 Brisbane 31.6/ / PE 13 Perth 38.2/ / DA 1 Darwin 34.7/ / HO 26 Hobart 28.3/ / CA 24 Canberra 34.6/ / Table 1: Capital city design temperatures applying DA9 method to the most recent ACDB-2011 (ellipsis... indicates URL prefix 46

3 Comparison with Table 2 in the results section of this paper shows that ASHRAE s new 0.4% design temperatures are not as stringent as would have been the case if the methods of the 1994 edition of DA9 had been applied to the latest observations of the BoM. This is because the variability of weather year-to-year is not accounted for by the ASHRAE methodology, but is beyond the scope of the present paper. Our purpose in this article is to compare ASHRAE 2013 design data with DA and with the 35th highest temperature of TMY2 files that have been released by NatHERS Fraction of Model Global TU Tullamarine (Melbourne Airport) Direct Horizontal Irradiance Diffuse Irradiance Direct Horizontal from Satellite Global / Model Clear Figure 2: Example from Melbourne s Tullamarine Airport. Satellitederived direct and global irradiance was checked to confirm they displayed the expected distribution. of DA9 option 2 warm-humid conditions from ASHRAE 0.4% wet-bulb may be due to improved fidelity of humidity sensors and greater coverage of hours of observations. DA9 coincident parameters may have been taken only at the hours of 9am, Noon, 3pm, and 6pm, with occasional observations at 9pm, and no later than midnight. ASHRAE design data are founded on the hourly and half-hourly records of automatic weather stations. Figure 1: Global Irradiance January 1, 1998 UT at 5km resolution hourly global and direct irradiance determined by BoM from meteorological satellites operated by Japan and NOAA. RESULTS The first result of the present paper is the comparison of the standing DA9 comfort design conditions with ASHRAE 0.4% annual design conditions at eight Australian capital cities in Table 2. DA9 Option 1 hot-dry conditions are almost identical with ASHRAE 0.4% dry-bulb at the Sydney Regional Office and also at the Brisbane, Perth, and Darwin airports, but otherwise vary between the two sets of design data. The greater variation The DA9 design data is based on an earlier epoch ( 1988) that may have been cooler than the subsequent quarter century, which is the basis of the ASHRAE design data. But it also must be kept in mind that DA9 included one standard deviation to account for year-to-year variability, while ASHRAE applies the same percentage rank across all 20 to 25 years of automatic weather station data. Because the two sets of design data are founded on different methodologies (3pm vs hourly) it is not possible to determine from Table 1 if warming has occurred at the CBD or airport locations given. The purpose of this table is to introduce the current climate baseline conditions at all Australian capital cities as most recently published by both AIRAH and ASHRAE. More detailed assessment of the standing DA9 system of determining design conditions can be considered by deriving them from the same 45-year ACDB developed by NIWA and Design DB/MCWB Design MCDB/WB ASHRAE Location BoM WMO DA9 opt 1 ASHRAE 0.4 DA9 opt 2 ASHRAE Sydney RO / / / / Adelaide KT / / / / Melbourne RO / / / / Brisbane Aero / / / / Perth Aero / / / / Darwin Aero / / / / Hobart RO / / / / Canberra Aero / / / / Table 2: Capital City design temperatures (DA versus ASHRAE % dry- and wet-bulb) 48

4 shared with UQ. For an example taken from just one of 80 detailed reports, consider the case of Sydney RO detailed at where DA9-comfort design dry-bulb is calculated to be 31.9 C. This was exceeded 10 days per year, including standard deviation of 3.2 days per year, such that load would be unmet and indoor temperature would float six or seven days in an average year. This calculation of DA9-style design dry-bulb is 0.8 C above the original DA9 design dry-bulb in Table 1. The URL above links to analysis that indicates the design dry-bulb at Sydney RO (near the CBD) has been increasing 2.7 C per century. VALIDATING THE UPDATED ACDB 2011, AND DISTILLATION OF ASHRAE-STYLE DESIGN TEMPERATURES The second result of this paper is to validate the ACDB 2011 as updated by NIWA with technical assistance from UQ. This has been achieved by first extracting design-conditions (Peterson and Liley 2013) and subsequently comparing them with ASHRAE Handbook of Fundamental 2013 designconditions. Design temperatures extracted by the ASHRAE-method are accessed by clicking Location Summary for any particular station posted at and searching by scrolling down to ASHRAE design temperatures, which this paper refers to as ASHRAE-style to differentiate from design temperatures published by ASHRAE in the Handbook of Fundamentals. The ASHRAE-style temperature level exceeded 0.4% in the ACDB was compared with ASHRAE Fundamentals (2013) 0.4% design data. Both datasets share 63 stations. These were plotted in Figure 1 (p.48, Ecolibrium May 2015), with the exception of three anomalous remote outback stations Tindal, Oodnadatta and Forrest where there were spurious records from the late 1960s. Most of the two sets agree within 0.3 C, despite the ACDB spanning the 45 years ASHRAE 2013 are based on 20-odd years, concluding Upon this plot we overlaid a linear regression fit with coefficient of determination (R² > 0.99) after excluding three outback outliers where we have found obvious errors in the 1960s portion of the ACDB. The concurrence of results was remarkable, with R² > 0.99 it can be said that ASHRAE % dry-bulb is 99% predicable on the basis of the ACDB 0.4% highest rank temperature. The last 1% of variability that the ASHRAE design temperature is based on is the 20 to 25 years ending The ASHRAE-style design temperatures are based on our 45-year annals of ENERGYPLUS TMY FILES RELEASED BY NATHERS 2012 The final result of this paper is to demonstrate the utility of TMY2 files by extracting pseudo-design conditions from each of the three weightings (A, B, and C) and comparing these to ASHRAE 2013 design conditions. Ecolibrium readers were probably not previously aware of the NatHERS Reference Meterological Year climate files 2012 announced at URL nathers.gov.au/accredited-software/hownathers-software-works/climate-zones. It is therefore important to highlight that these energy-simulation weather files have been developed from a quality-controlled data bank derivative of raw solar and meteorological data available from the BoM. The ACDB was commenced at the CSIRO (Walsh, et al. 1983) to cover 29 locations, extended by others to cover another 40 locations (Australian Greenhouse Office 2006). It has also been extended by NIWA on behalf of the Commonwealth, states and territories NatHERS scheme. This has released EnergyPlus TMY and CSIRO accurate RMY files for 69 locations from BoM records (45 years) after the TMY2 method of Marion & Urban (1995). Most NatHERS climate files 2012 TMY2A 0.4% DB and DP vary less than a degree from ASHRAE % design levels, with zero median difference among the original 29 ACDB stations. Correlation of 35th hottest TMY2 temperature (0.4%) was compared with ASHRAE 0.4% design dry-bulb in Figure 2 (p.48, Ecolibrium May 2015) for the first 29 stations that comprise the ACDB. Median discrepancy (TMY2 ASHRAE) is zero for both the A- and B- weighted NatHERS2012, while the median TMYC is 0.2 C higher than the corresponding ASHRAE design drybulb. The maximum discrepancy is a 2.4 C underestimate of the ASHRAE design temperature. But for most of the first 29 TMY2A files the 35th highest drybulb is within 0.5 C of ASHRAE 2013 design dry-bulb 0.4%. In conclusion, TMY files are no substitute for near-extreme design-data derived from many years of hourly data extracted from either WMO or ACDB archives. TMY files are essential for provision of bin-data of coincident parameters of solar and meteorological observations, necessary for the design of building-integrated services that minimise dependence on off-site energy networks. To facilitate right sizing of HVAC systems, each TMY2 file should be processed with the EnergyPlus Weather Data Utility, which references ASHRAE Handbook data, if available, to define design day conditions. TMY2 files are each a single synthetic year assembled in a statistically representative selection process from the whole ACDB, and so it is proposed that the 35th highest temperature (out of 8,760 hours) is generally comparable to ASHRAE 0.4% design temperature. Figure 2 (p.48, Ecolibrium May 2015) indicates the coefficient of determination (R²>0.95) is not significantly different with A, B, or C weighted TMY2 files, indicating nearly 5% of the variability of the 35th highest temperature cannot be predicted by the latest ASHRAE handbook 0.4% deign dry-bulb. The result is remarkable, because the TMY2 methodology also weights other factors such as solar radiation, which is assumed to be clear-sky in the load estimating methods of DA9 and ASHRAE Fundamentals. Graphical inspection of the TMY2 files created with three alternative weightings (A, B, and C) are presented in Figure 3 (a, b, and c) for the example of the Sydney Regional Office of the BoM. In each case these 8,760 hour scatter plots are overlayed by ASHRAE-style 0.4% design conditions. These figures illustrate with the round symbol labelled independent that pairing of the dry- and wet-bulb design temperatures might never occur in any particular year, if ever. Perhaps this result is of some value in deciding to employ simultaneously occurring conditions for correctly sizing HVAC systems. JUNE 2015 ECOLIBRIUM 49

5 Figure 3: (a,b,): Psychrometric plots of NatHERS 2012 TMY2 data for Sydney RO. TMY A-weighting (above) is most representative of solar. CONCLUSIONS A worldwide dataset of contemporary HVAC design data is available to anyone who purchases either the 2013 Fundamentals, or at least Chapter 14 Climatic Design Information from ASHRAE. For the purposes of building energy simulations, TMY2A files of the NatHERS 2012 analysis of the ACDB 2011 have been selected the contemporary climate ( ), and from these the ASHRAE-style 0.4% design temperature can be approximated (give or take a couple of degrees) by the 50

6 Figure 3: (c): Psychrometric plots of NatHERS 2012 TMY2 data for Sydney RO. TMY C-weighting is least representative of solar radiation. 35th hottest of the 8,760 hourly temperatures in each TMY2 file, while they are intended to provide coincident bin-data. Presently the only online source of Australian HVAC system design data are given by Peterson and Liley (2013 uq.id.au/e.peterson). The temperature exceeded 0.4% of the entire 45-year record of hourly temperatures ( ) closely predicts the ASHRAE % design temperature from their most recent quarter-century analysis ( 2010). This source also provides DA9-format comfort design temperatures for 80 locations around Australia based on the entire 45-year record of daily 3pm temperatures ( ), exceeded an average of 10 days including one standard deviation to account for inter-annual variability. The DA9-method generally comes up higher than ASHRAE 0.4%. At present the ASHRAE 2009 Fundamentals design conditions, based on the quarter century are included within NatHERS 2006 RMY files. Ideally ASHRAE s latest quartercentury design conditions ( ) should be appended to NatHERS 2012 TMY2A files. Because they are derived from nearly the same quarter-century segment of the ACDB 2011, such design data would enable correct-sizing of building services to suit the current climate. EnergyPlus weather developers are planning to do so via the website org/, with proper attribution and disclaimers specified by the official NatHERS Climate Files 2012 announcement. REFERENCES Australian Greenhouse Office (AGO 2006). RMY Australia Representative Meteorological Year Climate Files Developed for the Australia Greenhouse Office for use in complying with Building Code of Australia. Commonwealth of Australia, Department of the Environment and Water Resources, Australia Greenhouse Office, Canberra, ACT, Australia. Available from EnergyPlus Weather Data URL cfm/weather_data3.cfm/region=5_southwest_pacific_wmo_region_5/ country=aus/cname=australia Biello, D (2010). The New Normal?: Average Global Temperatures Continue to Rise. Scientific American. scientificamerican.com/article/average-globaltemperature-rise-creates-new-normal Carrier Air Conditioning Company Handbook of Air Conditioning System Design. Copyright McGraw-Hill, New York. Giles, J (2015) Breaks Heat Record, Challenging Global Warming Skeptics. New York Times, 16th January com/2015/01/17/science/earth/2014-was-hottest-year-on-recordsurpassing-2010.html?_r=0 Huang, Joe (2015). Pers Com, ASHRAE TC 4.2 Climate Data Chair , currently Secretary. Joseph, D.H. (1988). The Australian and American perspectives on design temperatures. Australian Refrigeration, Air Conditioning and Heating, November, P AIRAH, Melbourne. Liley, J.B., Nagle, P., and Grant, I. (2012). Revision and update of Reference Meteorological Years for the Australian NatHERS Meteorological Society of NZ 2012 Conference, November. files/tuesday_1000_liley_0.pdf Liley, J. B. (2013). Australian Climate Data and Reference Meteorological Years for NatHERS Prepared for Australian Federal Government Department of Resources, Energy and Tourism. NIWA Client Report: LAU JBL October NIWA Project: DCE13601 Marion, W.,Urban, K. (1995). User s Manual for TMY2s (Typical Meteorological Years). No. NREL/SP p. National Renewable Energy Laboratory, Golden, Colorado. Peterson, E., Williams, N., Gilbert, D., and Bremhorst, K. (2006). New air conditioning design temperatures for Queensland, Australia. AIRAH Ecolibrium, February 2006, p downloads/ pdf JUNE 2015 ECOLIBRIUM 51

7 Peterson, EL and Liley, JB (2013). Developing HVAC design conditions for Australian locations with hourly meteorological data. AIRAH The Future of HVAC conference, Melbourne Peterson-TP pdf Peterson, EL (2014) Climate zone mapping for air conditioners and heat pump devices. A joint initiative of Australian, State and Territory and New Zealand Governments. E3 Equipment Energy Efficiency, Department of Industry, Canberra, November energy-rating-labels/climate-label/documents-and-publications/?viewpublic ationid=2760 Ridley, B., & Boland, J. (2012). Altering Typical Meteorological Years to cater for Climate Change Proceedings of the Australian Solar Energy Society Conference. Saman, W; dedear, R; Soebarto, V; Boland, J; Belusko, M; Bennett, H; Ridley, B; Candido, C; and Deuble, M (2014). The impact of climate change on external and internal temperature conditions for air conditioning design. AIRAH Ecolibrium Forum, September 2014 p Content_Files/EcoLibrium/2014/September14/09-14-Eco-003.pdf Thevenard, D., & Cornick, S. (2013). Revising ASHRAE Climatic Data for Design and Standards Part 1: Overview and Data. ASHRAE Transactions, 119(2). Weiss, E. G. A. and Thompson, B. W. (eds) Air conditioning systems design manual, including load estimating and psychometrics. Mechanical Engineering Services, Department of Housing and Construction. Australian Government Publishing Service, Canberra. ISBN X Wickham, F.A. (3rd ed); Design Aid 9 Load Estimation & Psychrometrics, AIRAH/IRHACE, ACKNOWLEDGEMENTS The development of the Australian HVAC system design data website was developed by the research consortium of University of Queensland and National Institute for Water and Atmosphere (NIWA) with support from the Energy Efficiency division, Department of Resources, Energy and Tourism for presentation at the AIRAH Future of HVAC Conference Although the information or advice is believed to be correct, the authors and their employers disclaim responsibility for any inaccuracies contained within the website. The NatHERS climate files node/ was compiled from BoM raw climate data and then used to complete a typical year for every NatHERS climate zone in Australia. The data files are publicly funded data provided by the Commonwealth, and no person or entity may charge for its supply or use. Though the Commonwealth has exercised reasonable care and skill in the preparation and collation of the data files, the data is supplied on an as is basis, without warranty of any kind. We thank AIRAH s Ecolibrium Forum peer reviewers for their constructive comments on a previous draft. This required a lengthier presentation to arrive at conclusions relevant to rightsizing HVAC systems so they serve efficiently with a reasonable float of unmet hours the total time when set-point temperature is not met either by the HVAC system or by the plant. Technical Papers AIRAH is always seeking technical papers of merit for publication in Ecolibrium. If you are interested in submitting a paper for publication, visit and download the AIRAH guidelines for preparing technical papers. 52