Daryl R. Brown

The Prospects of Alternatives to Vapor Compression Technology for Space Cooling and Food Refrigeration Applications

This article identifies and describes five alternative cooling technologies (magnetic, thermionic, thermoacoustic, thermoelectric, and thermotunnel) and qualitatively assesses the prospects of each technology relative to vapor compression for space cooling and food refrigeration applications. Assessment of the alternatives was based on the theoretical maximum percent of Carnot efficiency, the current state of development, the best percent of Carnot efficiency currently achieved, developmental barriers, and the extent of development activity. The prospect for each alternative was assigned an overall qualitative rating based on the subjective, composite view of the five characteristics.

Flywheel Energy Storage: An Alternative to Batteries For UPS Systems

ABSTRACT Direct current (DC) system flywheel energy storage technology can be used as a substitute for batteries to provide backup power to an uninterruptible power supply (UPS) system. Although the initial cost will usually be higher, flywheels offer a much longer life, reduced maintenance, a smaller footprint, and better reliability compared to a battery. The combination of these characteristics will generally result in a lower life-cycle cost for a flywheel compared to a battery. Flywheels intended for UPS application are typically designed to provide power at their maximum rate for a period of about 15 seconds. In contrast, most batteries for UPS applications are designed to provide their maximum rated power for about 15 minutes. Therefore, using a flywheel instead of a battery will generally require a generator that can come up to full power within about 10 seconds, which is well within the capabilities of standby generators. With or without a standby generator, flywheels could be used to significant...

Hydrogen Delivery Scenario Analysis Model for Hydrogen Distribution Options

As with the distribution of any commodity, distribution of hydrogen depends on how the hydrogen is packaged, how far it must travel, and how much must be delivered. Few would argue that transporting a high-pressure gas is markedly different from transporting a cryogenic liquid— or even a liquid at standard temperature and pressure. Packaging affects not only density (weight/volume) but also the operation of potential delivery modes and onboard storage, a problem that has been called the grand challenge of the hydrogen economy. These three factors—packaging (which in turn affects shipment size and modal attributes), delivery distance, and demand—affect both the structure of potential delivery systems and their contribution to unit costs. This paper describes the hydrogen delivery scenario analysis model, a generalized model of hydrogen delivery that can be used to analyze the economic feasibility of various options for hydrogen distribution to markets of different sizes and types. Inputs may be user define...

Economic Energy Savings Potential in Federal Buildings

The primary objective of this study was to estimate the current life-cycle cost-effective (i.e., economic) energy savings potential in Federal buildings and the corresponding capital investment required to achieve these savings, with Federal financing. Estimates were developed for major categories of energy efficiency measures such as building envelope, heating system, cooling system, and lighting. The analysis was based on conditions (building stock and characteristics, retrofit technologies, interest rates, energy prices, etc.) existing in the late 1990s. The potential impact of changes to any of these factors in the future was not considered.

Building Energy Audit Report for Pearl Harbor, HI

A building energy audit was performed by a team of engineers from Pacific Northwest National Laboratory (PNNL) under contract to the Department of Energy/Federal Energy Management Program (FEMP). The effort used the Facility Energy Decision System (FEDS) model to determine how energy is consumed at selected Pearl Harbor buildings, identify cost-effective energy retrofit measures, and calculate the potential energy and cost savings. This report documents the findings of that assessment.

Building Energy Audit Report, for Hickam AFB, HI

A building energy assessment was performed by a team of engineers from Pacific Northwest National Laboratory (PNNL) under contract to the Department of Energy/Federal Energy Management program (FEMP). The effort used the Facility Energy Decision System (FEDS) model to determine how energy is consumed at Hickam AFB, identify the most cost-effective energy retrofit measures, and calculate the potential energy and cost savings. This documents reports the results of that assessment.

Economic Sizing and Dispatch of Central Energy Plant Equipment at the Navy Medical Center, San Diego.

The Navy operates a central energy plant providing cooling, heating, and electric power to their hospital in San Diego. With aging equipment, uncertain loads, and volatile energy prices, the Navy was facing critical issues regarding replacement equipment sizing and dispatch of all equipment at their facility. The Pacific Northwest National Laboratory a developed a spreadsheet model to determine the economic optimum size of new turbine generators and absorption chillers, and the economic dispatch of the entire central energy plant. This article describes the analytical approach taken for the study, with an emphasis on the optimization problems and strategies. Specific results for the Navy hospital are also presented.

Cost-effective application of stationary fuel cell technologies

ABSTRACT Fuel cells have several features that make them attractive candidates for on-site power generation. Electric conversion efficiency is good, ranging around 40 percent; overall energy efficiency, including the recovery of steam and/or hot water, is about 80 percent. Air emissions are so low that fuel cells have received exemptions from the standard environmental permitting process in some locations. Fuel cells do not rely on size economies of scale to reduce cost or improve performance, and are currently being developed at sub-kW to multi-MW sizes, which covers practically every application of interest to an end user. Currently operating fuel cells have proven to be highly reliable. In addition, fuel cells are very quiet and produce premium power for servicing sensitive electric loads. This article presents energy managers with information that will help them determine whether fuel cells could be effectively implemented at their facilities now or in the future. Included are sections providing an in...