4,512 research outputs found

    Procedure for Packing Weather Files for DOE-2.1e

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    Energy Systems laboratory (ESL) prepares 17 of Texas stations’ weather files for DOE-2.1e simulation every year. This report describes the procedure how to get and pack the weather data for DOE-2.1e simulation

    Analysing and Combining Partial Problem Solutions for Properly Informed Heuristic Generations

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    Finding an optimal path to the fixed goal state of a problem instance lying in an enormous search space may be described in the framework of the conventional A* algorithm. However, the estimated distance to the goal state, so called h_value, must be generated by an admissible heuristic such that it is not larger than but still as close as the unknown real distance to the goal. In this paper, we suggest a method of generating a heuristic with that property. After analyzing a number of devised partial problems, some are selected to be combined to produce a properly informed heuristic. In solving a complex problem with a fixed goal, some depth of fixed backward states is pre-stored. Those static backward states are also used for partial problem backward searches. For a given problem instance, the forward search is first performed for each of its partial problem. The dynamically generated space is combined with the static search space to produce the temporary search space, which is used to aid in the generation of each state heuristic for the course of problem solving. A novel method of constructing the temporary search space for each partial problem is suggested, in which each forward state found in the static backward space is back-propagated and propagated in the forward space. To show the effectiveness of our method, it has been massively experimented for instances of Rubik’s cube problem of some difficulty whose search space of states reachable from any given start state is known to cover 43*1018 states, the number of which even an 64-bit unsigned integer cannot hold. Keywords: A*, admissible heuristic, partial problems, dynamic forward search, static backward search, Rubik’s cub

    Procedure for Packing Weather Files for DOE-2.1e

    Get PDF
    Energy Systems laboratory (ESL) prepares 17 of Texas stations’ weather files for DOE-2.1e simulation every year. This report describes the procedure how to get and pack the weather data for DOE-2.1e simulation

    Development of an Improved Methodology for Analyzing Existing Single-Family Residential Energy Use

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    The purpose of this study was to develop an improved methodology for analyzing the energy use from existing single-family. The overall goal of this work is to make home energy audits more effective by providing homeowners and energy auditors with an improved and reliable tool to identify over-consumption in a residence by showing where the energy is inefficiently being used in the residence when compared to buildings of similar size in similar climates. Such a tool can be used by auditors to quickly assess the problems in the building, determine accurately what needs to be fixed and to provide useful guidance before arriving on-site. In order to accomplish this, an improved methodology for an easy-to-use, semi-automatic calibrated simulation that can determine potential energy conservation measures for single-family residences was developed and tested. As a first step, an easy-to-use simulation which can be used by homeowners who are not familiar with residential building energy analysis was developed. Users of this easy-to-use simulation are only required to input basic information of their houses such as construction year, size and location of the house, with the other inputs for building energy simulation being filled-in automatically using a newly established statistical house information database for Texas. Next, the easy-to-use simulation is calibrated using the semi-automatic calibrated simulation methodology that matches the simulated and actual utility electricity and natural gas use of the house. In order to develop this methodology, a sensitivity analysis was performed using a three-parameter change-point regression model that regresses the energy use against ambient temperature. The analysis showed the most significant simulation parameters that affect residential energy use that are decomposed into the baseload, the change-point temperature, and the cooling or heating slope. These parameters were used to calibrate each part of the building energy use against the actual monthly electricity and natural gas use. In the next step, the calibrated simulation parameters were compared with similar input parameters of a standard house that is compliant with the 2009 IECC to determine the differences in the parameters and give guidance about what characteristics of the house were below the energy efficient characteristics of the 2009 IECC-compliant house. Using this comparison, the less energy-efficient parameters of the house were determined as potential energy conservation measures for a future retrofit, and finally, the most cost effective measures were determined through a simple pay-back cost analysis. In order to verify the methodology, the both methods were tested on actual residence and the results were compared to determine if both procedures identified the same potential energy conservation measures. Once the procedure was demonstrated on the first case-study house, two additional houses were also tested to verify how well the procedure worked. The comparisons showed that the easy-to-use and the actual simulations resulted in the same potential energy conservation measures with the similar pay-back period, and thus was verified that the easy-to-use simulation can be used for a home energy audit procedure with reliability

    Charge Transfer Induced Molecular Hole Doping into Thin Film of Metal-Organic-Frameworks

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    Despite the highly porous nature with significantly large surface area, metal organic frameworks (MOFs) can be hardly used in electronic, and optoelectronic devices due to their extremely poor electrical conductivity. Therefore, the study of MOF thin films that require electron transport or conductivity in combination with the everlasting porosity is highly desirable. In the present work, thin films of Co3(NDC)3DMF4 MOFs with improved electronic conductivity are synthesized using layer-by-layer and doctor blade coating techniques followed by iodine doping. The as-prepared and doped films are characterized using FE-SEM, EDX, UV/Visible spectroscopy, XPS, current-voltage measurement, photoluminescence spectroscopy, cyclic voltammetry, and incident photon to current efficiency measurements. In addition, the electronic and semiconductor property of the MOF films are characterized using Hall Effect measurement, which reveals that in contrast to the insulator behavior of the as-prepared MOFs, the iodine doped MOFs behave as a p-type semiconductor. This is caused by charge transfer induced hole doping into the frameworks. The observed charge transfer induced hole doping phenomenon is also confirmed by calculating the densities of states of the as-prepared and iodine doped MOFs based on density functional theory. Photoluminescence spectroscopy demonstrate an efficient interfacial charge transfer between TiO2 and iodine doped MOFs, which can be applied to harvest solar radiations.Comment: Main paper (19 pages, 6 figures) and supplementary information (15 pages, 10 figures), accepted in ACS Appl. Materials & Interface
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