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This paper announces the completion of a large new data set of International Weather for Energy Calculations 2 (IWEC2), i.e., typical year, weather files for 3012 locations outside of the U.S. and Canada and describes the procedures used to produce these weather files, including how the raw weather data from the Integrated Surface Hourly (ISH) database were processed and how missing records and unrecorded climate parameters have been derived. Particular attention was paid to the derivation of global horizontal and direct normal solar radiation using a combination of empirical and analytical solar models. The procedure used to select the typical months making up the IWEC2 files from the historical weather record, is also explained. These IWEC2 weather files are then compared to other sources of international weather data and to an earlier, smaller set of IWEC weather files developed in 2001. The IWEC2 weather files are found to have very similar heating degree days, and slightly more cooling degree-days than the IWEC. There is substantially more variation in the solar radiation, with the IWEC2 weather files having somewhat less total and somewhat more direct normal solar radiation than the earlier IWEC weather files.

The climatic design condition tables that comprise the Climatic Design Information chapter of the ASHRAE Handbook of Fundamentals has been used by generations of engineers for sizing HVAC equipment. The ASHRAE design procedure has evolved over time from using single design temperatures to calculate heating and cooling design loads, to a proliferation of hypothetical design days that are still built around design temperatures as the daily peak, with the temperatures for the other hours filled by fitting a standard daily temperature profile to an average daily temperature range calculated for the hottest month. It is important to recognize that while there are statistical bases for each climatic parameter, there has been no statistical verification of the ASHRAE design day procedure in its entirety. The Integrated Surface Database maintained by the National Climatic Data Center contains the hourly climatic records of up to 13,600 weather stations around the world spanning several decades.

The objective of this project is to develop a flexible fenestration simulation program based on fundamental physical modeling of fenestration heat flows that uses an intelligent default mechanism with iterative search capabilities to produce a physically realistic fenestration system based on user inputs, with the minimum inputs being only the lumped parameters of U-factor and solar heat gain coefficient (SHGC). As more inputs (e.g., number of panes, gap width, framematerial, etc.) are provided, the program will narrow the search to the remaining unknown properties so that the fenestration system bulk properties and other physical characteristics of the synthesized fenestration system will match available information from actual fenestration systems. In some cases, this information may be limited to observable characteristics, such as dimensions, number of glass panes, and frame materials. Using such limited input information, the tool generates a detailed physical description of a fenestration system based on real components available on the market today. This computer program is designed to be used in a standalone mode to produce a text file containing information suitable to be input into popular building simulation engines.

The paper summarizes the results of a series of analyses to assess the impact of the selection procedure used to generate of typical year weather on annual building energy use. The building energy analysis is carried out using detailed whole building simulation tool that utilizes hourly typical year weather files. Annual energy use for prototypical office buildings are obtained for 10 sites representing a wide range of climatic conditions in the U.S. In particular, the analyses presented in this paper evaluate the impacts of weighting factors for various weather variables and of the length of historical data used on predicting the energy use of building systems. The results of the analysis indicated that a maximum of 5% difference in annual office building energy use can result from the selection procedure used to generate typical weather year for the 10 US climates considered in this study.

The aim of this paper is to assess how policy goals in relation to the promotion of green growth, energy security, pollution control and greenhouse gas (GHG) emissions reductions have been aligned in policies that have been implemented in selected countries during the last decades as a basis for discussing how a multi objective policy paradigm can contribute to future climate change mitigation. The paper includes country case studies from Brazil, Canada, China, the European Union (EU), India, Japan, Mexico, Nigeria, South Africa, South Korea and the United States covering renewable energy options, industry, transportation, the residential sector and cross-sectoral policies. These countries and regions together contribute more than two thirds of global GHG emissions. The paper finds that policies that are nationally driven and that have multiple objectives, including climate-change mitigation, have been widely applied for decades in both developing countries and industrialised countries. Many of these policies have a long history, and adjustments have taken place based on experience and cost effectiveness concerns. Various energy and climate-change policy goals have worked together in these countries, and in practice a mix of policies reflecting specific priorities and contexts have been pursued. In this way, climate-change mitigation has been aligned with other policy objectives and integrated into broader policy packages, though in many cases specific attention has not been given to the achievement of large GHG emission reductions. Based on these experiences with policy implementation, the paper highlights a number of key coordination and design issues that are pertinent to the successful joint implementation of several energy and climate-change policy goals.

Over the past 15 years, low-emissivity and other technological improvements have significantly improved the energy efficiency of windows sold in the United States. However, as interest increases in the concept of zero-energy homes - buildings that do not consume any nonrenewable or net energy from the utility grid - even today's highest-performance window products will not be sufficient. This simulation study compares today's typical residential windows, today's most efficient residential windows, and several options for advanced window technologies, including products with improved fixed or static properties and products with dynamic solar heat gain properties. Nine representative window products are examined in eight representative U.S. climates. Annual energy and peak demand impacts are investigated. We conclude that a new generation of window products is necessary for zero-energy homes if windows are not to be an energy drain on these homes. Windows with dynamic solar heat gain properties are found to offer significant potential in reducing energy use and peak demands in northern and central climates, while windows with very low (static) solar heat gain properties offer the most potential in southern climates.

Over the past 15 years, low-emissivity and other technological improvements have significantly improved the energy efficiency of windows sold in the United States. However,as interest increases in the concept of zero-energy homes–buildings that do not consume any non-renewable or net energy from the utility grid–even today's highest-performance window products will not be sufficient. This simulation study compares today's typical residential windows, today's most efficient residential windows, and several options for advanced window technologies including both products with improved fixed or static properties and products with dynamic solar heat gain properties. Nine representative window products are examined in eight representative US climates. Annual energy and peak demand impacts are investigated. We conclude that a new generation of window products is necessary for zero-energy homes if windows are not to be an energy drain on these homes. Windows with dynamic solar heat gain properties are found to offer significant potentials to reduce energy use and peak demands in northern and central climates while windows with very low (static) solar heat gain properties offer the most potential in southern climates.

A new building energy simulation program, known as EnergyPlus, was first released in April 2001. EnergyPlus builds on the capabilities and features of BLAST and DOE-2 and includes many simulation features, such as variable time steps, configurable modular systems that are integrated with a heat balance-based zone simulation, and input and output data structures tailored to facilitate third party module and interface development — features that have not been available together in a mainstream building energy simulation program. Other simulation capabilities include three thermal comfort models, extensive daylighting and advanced fenestration capabilities, multi-zone airflow modeling, more robust HVAC equipment models, more flexible system modeling, and photovoltaic simulation. Currently, more than 10 private sector companies have stated their intentions to create user interfaces for EnergyPlus. Since EnergyPlus was released in April 2001, more than 20,000 copies have been downloaded, with users in more than 90 countries.

A series of experiments in Florida residences have measured the impact of increasing roof solar reflectance on space cooling. In tests on eleven homes with the roof color changed in mid-summer, the average cooling energy use was reduced by 19%. Measurements and infrared thermography show that a significant part of the savings is due to interactions when the duct system is located in the attic space. An improved residential attic and duct simulation model, taking these experimental results into account, has been implemented in the DOE-2.1E building energy simulation program. The model was then used to estimate the impact of reflective roofing in fourteen different climatic locations around the United States.

The Peoples' Republic of China is distinct among developing countries in that it has significant heating loads over much of the country. Since almost half of the urban residential buildings are located in climates colder than Washington State, the demand for space heating will skyrocket if the current building boom continues. Space heating energy use is constrained by mandated coal allocations resulting in partially heated buildings with indoor temperatures much below design conditions. This underheating masks the energy savings obtained from energy-efficient boilers and building designs. Economic calculations comparing energy savings with increased construction costs are skewed by the unmet heating loads as well as by government-subsidized coal prices that are below actual costs. From the perspective of building owners and managers, building energy conservation is still economically attractive in the cold Northeast, where the cost of conserved coal is half that of the subsidized coal price, but is difficult to justify in terms of economic payback in Beijing or Shanghai.