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Energy standards and codes, including ASHRAE/IES Standard 90.1 and ANSI/ASHRAE Standard 90.2, have used cooling degree-day (CDD) and heating degree-day (HDD) values, and representative weather files, in the development and specification of criteria. Since the selection ofthe previous CDD and HDD values and representative weather files in 2002, climate data has become available for a more-recent period of record and for a more-extensive set of U.S., Canadian, and other international locations. The CDD and HDD values for individual locations and the representative weather files for those locations have changed, in some cases, markedly. Consequently, it was necessary to update the CDD and HDD values and the representative weatherfiles being used for the development and specification of criteria. This is the second paper in a two-paper series. The first paper explains how the CDD and HDD baseline values were updated and provided those values for the various climate zones. This secondpaper explains the process used to select representative weather files for the various climate zones, including the use of the degree-day-radius metric and minimum population thresholds. This paper lists three sets ofrepresentative weather files: global, U.S., and Canadian. [ABSTRACT FROM AUTHOR]

Energy standards and codes, including ASHRAE/IES Standard 90.1 and ASHRAE Standard 90.2, have used cooling degree day (CDD) and heating degree day (HDD) values and representative weather files in the development and specification of criteria. Since the selection of the previous CDD and HDD values and representative weather files in 2002, climate data have become available for a more recent period ofrecord and for a more extensive set of U.S., Canadian, and other international locations. The CDD and HDD values for individual locations, and the representative weather files for those locations, have changed, in some cases markedly. Consequently, it was necessary to update the CDD and HDD values and the representative weather files being used for the development and specification of criteria. This first paper in a two-paper series explains how the CDD and HDD baseline values were updated, including the use of population to inform the determination of the CDD and HDD baseline values. This paper provides those values for the various climate zones, including Climate Zone 0, newly established in ASHRAE Standard 169- 2013. The second paper explains the process used to select representative weather files for the various climate zones and lists those weather files. [ABSTRACT FROM AUTHOR]

The challenge of the Science House at the Science Museum of Minnesota was to create habitable, cold-climate architecture that would result in a net zero energy building and to get it built in a ‘low bid’ environment. The design team used scientific evaluation to resolve design integration conflicts between functionality, aesthetics, and performance. The team significantly reduced annual energy consumption, beginning with expectations of use by the owner and architectural form and then by adding a renewable energy source. The defining question became, ‘How much building, with fixed program requirements, can we build and generate power for with the given budget?’ The resulting building uses passive solar design, daylighting, ground-source heat pumps, and photovoltaic (PV) panels as the major design strategies. This paper documents the predicted energy use and actual monitored performance, comparing to a calibrated DOE-2 model. It shows the extent of load reduction achieved with passive solar design. A challenge for getting to ‘real zero’ is the difference between expected performance and actual building performance. This paper illustrates how measured data are used to trace the causes to unexpected equipment performance, heat pump behavior, and off-line PV panels. Assumptions regarding occupancy and building use during the design phase often differ from their actual use; this makes operating a building for zero energy an additional challenge beyond just designing one. Overall, the actual building is exceeding the design goals, using on average 22,385 Btu/ft2·yr (0·71 kWh/m2·yr) annually and generating 30,864 Btu/ft2·yr (0.97 kWh/m2·yr) to result in a building that generates more energy than it uses. [ABSTRACT FROM AUTHOR]

ASHRAE Research project 1273-RP recalculated and expanded the tables of climatic design conditions in the ASHRAE Handbook—Fundamentals. These tables provide values of dry-bulb, wet-bulb, and dew-point temperature, enthalpy, and wind speed at various frequencies of occurrence over annual and monthly periods and for some of these, mean coincident values of other variables of interest. Compared to the previous edition of the Handbook, the new tables include additional elements and are calculated for a much greater number of stations over a longer period of record. This paper explains the procedure used to compute the design conditions, the data sources used, the techniques employed to screen out erroneous data, and the completeness criteria required by the calculation- It also provides a summary of the stations included in the 2005 Handbook and a brief description of how the new values compare to those published in the 2001 edition. Finally, the paper provides an overview of the capability of the Weather Data Viewer, a companion CD-ROM that gives full access to the frequency information used to compile the tables of climatic design conditions. [ABSTRACT FROM AUTHOR]

How energy efficient can commercial and multifamily buildings become in the near future if first cost is not considered? This paper describes how building energy simulation modeling was used to try to answer this question. The first step was to assemble a list of energy efficiency measures that can be included in the design of nonresidential buildings. The list included both commonly used and cutting edge energy efficiency measures with the goal of being comprehensive, at least for measures that can be modeled. Input was sought from diverse experts to ensure that the list of measures did not exclude any important ones. From the resulting list of almost 400 measures, 30 were chosen. 16 Energy Plusprototype buildings that were consistent with ANSI/ASHRAE/IES Standard 90.1-2013 (ASHRAE 2013a) across 17 climate zones were used as baseline models. The 30 measures were individually modeled using an open source Python-based library called Eppy, created for the study. Each of the 30 measures, often with many options, were applied to each building and climate combination. In general, the measures were applied in the following order: • Reduce internal loads • Reduce building envelope loads • Reduce HVAC distribution system losses • Decrease HVAC equipment energy consumption • Major HVAC reconfigurations. Aftereachmeasurewasapplied toeachof the272building and climate combinations, if the energy consumption was reduced, it remained in the model. After all 30 measures were applied, the projected U.S. nationalweightedenergyconsumption fornewbuildingswasnearly cut in half compared to ANSI/ASHRAE/IES Standard 90.1-2013. [ABSTRACT FROM AUTHOR]

The Western Cooling Challenge is a multiple-winner competition that invites manufacturers to develop and commercialize the next generation of rooftop packaged air conditioners appropriate for dry western United States climates. Certification centers on requirements for sensible energy efficiency at two separate test conditions that are representative of western climates. Criteria for minimum energy and water use efficiency were developed based on the estimated performance of market-available retrofit solutions for conventional rooftop package units; thus it is expected that comprehensive ground-up system designs should easily achieve the performance requirements. This paper outlines and discusses the development of the test protocol and performance criteria for the Challenge. The choice of laboratory test conditions is discussed. The rationale for and calculation of performance metrics including nominal cooling capacity and credited cooling capacity are presented. Additionally, the assumptions underlying requirements for minimum sensible energy efficiency are summarized, and key nonperformance-based criteria for the program are explained. [ABSTRACT FROM AUTHOR]

Two supply fan speed control methods for a variable airflow volume (VAV) system using the fan airflow station (FAS) are introduced in this paper In the first method, the supply fan speed is controlled to maintain an optimized system resistance (S), which is calculated based on the measured fan head, and airflow. In the second method, the supply fan speed is controlled to maintain the duct static pressure set point, which is reset based on the airflow ratio measured by the FAS. Both methods can make the terminal box open more compared with the conventional supply fan speed control using a fixed duct static pressure set point. These innovative methods can be applied to systems with either direct digital control (DDC) or pneumatic control terminal boxes. The case studies show that the new control methods can significantly save supply fan power and improve fan efficiency. [ABSTRACT FROM AUTHOR]

The design of this 1280 square foot, 3-bedroom Denver zero energy home (ZEH) carefully combines envelope efficiency, efficient equipment, appliances and lighting, a photovoltaic (PV) system, and passive and active solar thermal features to exceed the net zero energy goal. In January, 2006 a data acquisition system was installed in the home to monitor its performance over the course of a year. This paper presents full year of energy performance data on the home. From April 2006 through March 2007 the home's 4 kW PV system produced 5127 kWh of AC electricity. Only 3585 kWh of electricity and 57 therms of natural gas were used in the home during this period. On a source energy basis, the home produced 24% more energy than it used. The energy used for space heating, water heating, and lighting have been dramatically reduced through superinsulation, passive solar tempering, solar water heating, compact florescent lights and other efficiency measures. The energy used in the home is now dominated by appliance and plug loads determined by occupant choices and behavior These loads constitute 58% of all the source energy used in the home. Because these loads are generally outside of the control of the home designer and vary considerably with different occupants, sizing a PV system to achieve zero net energy performance is challenging. This case studies demonstrates that it is possible to build efficient affordable zero energy homes in cold climates with standard building techniques and materials, simple mechanical systems, and off-the-shelf equipment. [ABSTRACT FROM AUTHOR]

This paper shows that the energy requirements for today's typical efficient window products (i.e., Energy Star™ products) are significant when compared to the needs of zero-energy homes (ZEHs). Through the use of whole house energy modeling, typical efficient products are evaluated in five US climates and compared against the requirements for ZEHs. Products that meet these needs are defined as a function of climate. In heating-dominated climates, windows with U-factors of 0.10 Btu/h·ft2·°F (0.57 W/m2·K) will become energy neutral. In mixed heating/cooling climates, a low U-factor is not as significant as the ability to modulate from high solar heat gain coefficients (SHGCs) (heating season) to low SHGCs (cooling season). [ABSTRACT FROM AUTHOR]

This paper proposes a validated and integrated calculation procedure for the prediction of solar spectra incident on vertical (or otherwise tilted) windows as a function of local climatic conditions in North America or, ultimately, any site in the world. This procedure is aimed at engineers with a modest background in meteorology, climatology, or atmospheric sciences and, therefore, tries to reconcile accuracy, flexibility, and ease of use. The procedure is backed by a thorough literature review and detailed performance assessment. The spectral radiation model (SMARTS) finally selected for its capabilities and performance (among other factors) is not based on any empirical relationship. It is capable of predicting spectral and broadband irradiance, as well as illuminance under cloudless skies at any location where the required inputs are available. The accuracy of the produced spectra is comparable to that from state-of-the-art rigorous atmospheric models or from the best instruments. Such accurate results can only be obtained if a precise description of the atmospheric conditions is input to the model. A detailed methodology is described to obtain the basic atmospheric variables for any location in North America. It is anticipated that the current improvements in remote sensing from satellites will provide the means to extend the method to any site in the world. To illustrate the method, an example of application is provided for the various facades of the ASHRAE headquarters in Atlanta. Substantial improvements in the calculation of solar heat gains through spectrally selective fenestration and the resulting cooling loads in buildings are the ultimate benefits expected from the procedure. [ABSTRACT FROM AUTHOR]

A project completed in 2004 titled "Alternatives to Compressor Cooling" showed that carefully controlled mechanical ventilation cooling can significantly reduce summer peak load and can eliminate the need for vapor compression cooling in areas between the California coastline and the central valley. This technology is most applicable in thy climates where vapor compression cooling is needed only a few days of the year and hot, dry climates that have a dry-bulb temperature range approaching 30°F (17°C), which include much of the West, Southwest, and areas of the Northeast. This paper describes the technology and its development, reviews field tests completed under the California Energy Commission and Department of Energy Building America program sponsorship, and presents computer simulation and monitoring results. For the California houses and climates evaluated, cooling demand was reduced 40% to 79% and cooling energy savings ranged from 0% to 65%. [ABSTRACT FROM AUTHOR]

Recent changes from manual to automated weather observing systems at most airports have introduced biases that influence building energy calculations. In particular, these biases compromise the accuracy of model-derived solar radiation. This paper summarizes changes in methods and instrumentation used to observe weather over the past decade, the consequences that these changes have on building energy calculations, and a new solar radiation model developed to help alleviate these consequences. This new model uses observations from the U.S. National Weather Service's Automated Surface Observation Systems (ASOS) to estimate global horizontal, direct normal, and diffuse horizontal solar radiation and allows for application to different climatic regimes while minimizing season-specific and cloud-condition-specific mean error biases. Model evaluation reveals that errors in solar radiation estimation are comparable to other contemporary solar radiation models. [ABSTRACT FROM AUTHOR]

This paper reports the relative energy consumption of prototype VAV and CAV air-conditioning systems under various load conditions simulating those of a typical office building in humid tropical climates such as Singapore's. Tests were conducted inside two adjoining environmental chambers where space loading was varied from 0.217 to 0.295 kW/m² (68.81 to 93.54 Btu/h ft²) with corresponding sensible heat ratio (SHR) ranging from 0.65 to 0.9. The VAV system consistently consumed less energy compared to the CAV system under constant as well as variable load conditions. The percentage energy saving ranged from 21.97% at 0.217 kW/m² (68.81 Btu/h ft²) to 12.42% at 0.295 kW/m² (93.54 Btu/h ft²) under constant loading, and it decreased with increased space loading. The experiments measured moderate energy savings under the experimental conditions that are assumed to be the typical load condition in Singapore. Because the implementation costs are significant, it appears that a VAV system has marginal economic benefit in Singapore. [ABSTRACT FROM AUTHOR]

Air leakage causes significant energy losses in buildings and depends on local pressure gradients caused by temperature differences and wind. Airtightness requirements of the 2012 International Energy Conservation Code change by location. However, airtightness codes do not consider resistance caused by air leakage from wind-driven pressure gradients, only temperature-difference-driven pressure gradients. Codes for thermal resistance also don't reflect reductions in thermal performance caused by air leakage, excluding air leakage completely in thermal resistance calculations. Air leakage needs to be included in thermal resistance codes and wind factors need to be included in airtightness standards to better understand how air leakage affects overall thermal performance. We simulated a 40 ×25 ft (12 × 7.6 m), two-story home with three different levels of airtightness to study effective thermal resistance. We also modeled the home with codecompliant airtightness to study energy loss through the building envelope as a function of localized weather. With the results, we generated contour maps to visualize trends of increased energy loss and decreased thermal resistance of code-insulated homes across the United States. These results indicate that present code requirements do not effectively account for the impact of air leakage on thermal performance or reveal where in the United States airtightness of buildings most affects energy performance. [ABSTRACT FROM AUTHOR]

Optimizing energy efficiency in real-time operation is a critical issue for cold-climate heat pump systems, while model based control/optimization strategies may involve costly modeling and calibration. As a model-free control strategy, extremum seeking control has been applied to optimize the operational efficiency for three configurations: internal heat exchanger cycle vapor injection, flash tank vapor injection and cascade heat pump. Simulation studies validate the effectiveness of the control strategy. [ABSTRACT FROM AUTHOR]

This article presents a climate control strategy for the preservation of collections, specially designed for and installed at the Amazonian ethnographic storage of the Museu Paraense Emílio Goeldi in Belém, Brazil. Technologically simple and low cost to install, the system is robust and economical when in operation. It aims to maintain the relative humidity below 60% to prevent the collection from fungal and bacterial attacks while allowing the temperature to vary with the outside climate. The system has maintained the designed preservation environment for the last five years with minimum energy consumption and low maintenance costs. The strategy has also proven its robustness to maintain the conservation environment even during extended power outages common in the region. [ABSTRACT FROM AUTHOR]

The purpose of this work is to add to the understanding of the complex human body and its functions with the aid of the physical laws of nature. Here, we reveal the influence that the environmental temperature has on a person `s ability to do work, which in turn affects the nation `s ability to produce goods and services to contribute to the advancement of the nation's economy. The implementation of the Second Law of Thermodynamics to the human body predicts that the useful work per person in moderate, temperate climates is more than that in extreme hot or frigid climates. The availability of comfortable environments for the labor force in temperate climate can foster workers' productivity to an optimum level. Therefore, countries consume a high amount of energy to produce this optimum productive environment to increase the growth of services and products. An investigation of the cost of artificially producing a comfortable environment shows a higher cost of cooling over heating. In this study first, we evaluate the labor force's productivity of 169 countries that have data available by measuring the total goods and services, which are produced per year through Gross Domestic Products per Capita (GDP) data. Secondly, a city from each country is randomly selected to represent the average mean temperature of these countries. The data shows that the predispositions of the countries where the climatic conditions are extremely hot or frigid have poorer labor force's productivity than those with moderate, temperate climates. This finding add to our understanding of human beings; the fact that their behaviors and performances are affected by their environment; and how ultimately, our economic wellbeing is affected by physical factors such as the temperature. [ABSTRACT FROM AUTHOR]

In low-energy building design; energy consumption due to space conditioning is responsible for over 30% of total energy consumed in commercial buildings. In an effort to evaluate low-energy building designs, two commercial office buildings were each monitored for 16 months. A comparison of the two buildings, with different ventilation strategies but located in the same climate, is presented. One is naturally ventilated without mechanical chillers, and the other uses a raised floor system combined with a chilled ceiling for space conditioning. The data were evaluated for thermal comfort, ventilation effectiveness, and energy efficiency. The buildings were of similar configuration: three stories, with a central atrium and an open floor plan, located in office parks outside of London, UK. The energy consumption for the mechanically ventilated building was significantly higher on a kWh per floor area basis (318 kWh/m2 [29.6 kwh/ft2] for the mechanically ventilated building and 216 kWh/m2 [20.1 kWh/ft2]for the naturally ventilated building), primarily due to the energy required for cooling and fan energy. The temperature of the office space also varied depending on the ventilation used. Mechanically ventilated buildings had much tighter control of the interior temperature when compared with the naturally ventilated building. Both buildings had areas for improvement to further reduce energy consumption. [ABSTRACT FROM AUTHOR]

A new method for optimizing the indoor thermal climate under nonuniform temperature distribution by accounting for energy conservation and indoor thermal comfort has been developed. Temperature settings and arrangements of thermal sensors of an HVAC system are optimized using a genetic algorithm-based method (e.g., Cantu-Paz 2000). In a genetic algorithm, design variables are coded into a ‘chromosome’ that is subject to a series of genetic operations in search of an optimized solution. An optimal sensor arrangement requires (1) the air temperature at the sensor location to correlate well with the thermal comfort of occupants regardless of seasonal and load variations and (2) low energy consumption to be maintained while preserving thermal comfort with an adequate temperature setting. Using an index called the contribution ratio of indoor climate (CRI), the results obtained for an optimized sensor arrangement and temperature settings are presented and compared with the results of alternative arrangements. [ABSTRACT FROM AUTHOR]

The Equivalent Wall Method is applied to compare the thermal performance of concrete construction technologies against standard wood frame systems. The Equivalent Wall Method provides a technique to incorporate the multi-dimensional heat conduction steady-state and transient characteristics of an entire wall assembly, including the clear wall and wall detail regions, into a whole building energy simulation program. Several different types of precast concrete panel (PCP), insulated concrete form (ICF), and wood frame constructions were analyzed using this method. Whole building dynamic modeling was employed to calculate the energy savings of a typical single-family residence constructed with PCP and ICF systems compared to wood frame systems for six different US climates. Some configurations of concrete systems are shown to offer an improvement in performance over the wood frame systems, but the amount of improvement depends on, in decreasing order of significance, airtightness, insulation continuity, and magnitude and location of thermal capacitance. [ABSTRACT FROM AUTHOR]

A methodology to evaluate the energy consumption of centralized and decentralized pumping systems in ground-coupled heat pump (GCHP) systems is presented. The analysis covers the first costs of the piping (interior and exterior) and of the circulating pump, as well as annual pumping energy costs. The methodology is applied to two buildings representing two distinct building/climate combinations. Results show that when the cost of the pumps and their installation are added to the life-cycle energy cost of 20 years of pumping, centralized systems for both buildings have total pumping costs that are lower than decentralized systems. It is also shown that the annual energy-weighted average wire-to-water pump efficiency of centralized systems is much better than for decentralized systems. Despite this pumping cost advantage, the overall costs (interior piping + exterior piping + pumping-related costs) of centralized systems are higher than for decentralized systems. This is primarily due to the high interior piping costs of centralized systems. [ABSTRACT FROM AUTHOR]

The laboratory air-handling unit (LAHU) system is designed to improve building energy performance and indoor air quality (IAQ) in laboratory buildings. The LAHU system sends more (up to 100%) outside air to the office section and recirculates the office section air to the laboratory section. This theoretical study shows that the potential annual thermal energy savings varies from 20% up to 40% depending on the climate and ratio of office airflow to the laboratory section airflow. The LAHU provides more outside air intake directly to the office section during both cold winter and hot summer months when the IAQ is critical for building occupants. When the office airflow ratio is less than 50%, the LAHU provides close to 100%, outside air to the office section at all times. [ABSTRACT FROM AUTHOR]