Search

The current generation of energy codes were born in the 1970s with the sole purpose of conserving energy in homes and buildings, and with no guidance surrounding renewable energy generation or grid integration for those structures. Over the intervening decades, that singular purpose has been complemented by increasing demands to reduce greenhouse gas emissions and to utilize a lower-carbon mix of fuel types. At the same time, the falling costs of renewable energy options, especially solar, have raised the importance of an optimizing calculus between renewable supply options and energy demand reduction options. The paper first reviews the framework for establishing the renewable/efficiency balance in California's Title 24-2019 Residential code. Based on additional analysis, the paper then presents a new framework that encompasses the range of U.S. climate zones and building types covered by the model energy codes, with a special focus on single family homes. This optimization framework is analyzed for its implications to update prescriptive, performance, and rating (such as the Energy Rating Index, or ERI) compliance paths in the model codes. The calculus is also examined for its application in determining impacts of renewable/efficiency combinations on electric grid stability. Additional topics covered include accounting for procuring onsite and offsite renewable energy and for measuring increases in building resiliency. The paper then offers recommendations for code developers by addressing the underlying code issues with regards to accounting, reporting, compliance, and enforcement. [ABSTRACT FROM AUTHOR]

Historical structures incur diverse challenges associated with energy consumption, specifically those surrounding opportunities for potential improvements. In the U.S., heating and cooling of spaces can account for up to half of all energy usage within a home. As a result, identification of cost-effective methods towards enhancing energy efficiency represents critical information for homeowners and businesses alike, and a measurable estimator of potential monetary investment and return. In this paper, a novel DC-powered picogrid is developed to support a local weather station adjacent to a residential home in order to optimize its energy consumption. Though regional meteorological data is readily available from numerous online cloud-services, in-situ environmental measurements afford more building-specific insights, ranging from wind direction and speed, humidity and dew-point levels, and UV and irradiance measurements. When coupled with on-site renewable energy generation such as solar and wind power, this weather data can drive real-time electrical management decisions (e.g., storing or expending battery energy, selling electricity to the grid, etc.), and also be leveraged for daily and weekly power consumption and generation forecasting. These findings illustrate the benefits of DC-powered designs, and the capability of low-cost sensors to improve residential energy administration. [ABSTRACT FROM AUTHOR]

Most larger buildings rely on one or more chillers operating on-demand to instantaneously meet building thermal loads as they occur. Unfortunately, the cost of electricity is highest during daytime, on-peak periods when building thermal loads are highest. Cool thermal energy storage (CTES) is a proven technology that enables decoupling the production of cooling from the coincident demand for cooling. CTES systems typically use either a single stratified chilled-water tank or a multiplicity of ice storage modules as a means of storing thermal energy during favorable chiller operating periods for later use to meet building cooling demands. For decades, building owners have benefited from CTES systems because of their ability to reduce utility costs by shifting the production of cooling from high cost on-peak periods to low cost off-peak periods. With increasing deployment of renewable energy generation, an additional application is provided for CTES related to alleviating problems associated with this intermittent source of electricity generation. As a technically mature and relatively inexpensive means of providing end-use electricity demand management, CTES has the potential to bridge mismatches between intermittent renewable generation and the utility aggregate demand for electricity. As we show in this paper, CTES is a technology that offers the potential to increase the deployment of renewable energy generation. This paper describes CTES design and control strategies that aim to more effectively use the generation of electricity from renewable energy resources. Specifically, one CTES control strategy discussed in this paper will charge the thermal storage system when renewable electricity generation is available and discharge storage to meet building cooling loads during periods of time when renewable energy is not available. This control strategy maximizes the fraction of the chiller's energy consumption met by electricity generated from wind or solar. A second CTES control strategy will maximize the net economic benefit of owning and operating a CTES system, based on equipment costs for both the CTES and the renewable generation systems and the operating cost of the net electric demand after wind or solar generation according to a time-of-use electricity rate structure. To illustrate the positive impact of CTES to enable increased penetration of renewable energy systems, an analysis is performed for a secondary school in the Los Angeles area. Simulated cooling loads for the prototypical school are based on the U.S. Department of Energy Commercial Reference Building Models (2011). To meet primary thermal loads, the secondary school employs air-cooled chillers and an ice storage system. The results show a trade-off between maximizing the use of renewable power and minimizing life-cycle cost, but a storage system designed to optimize the portion of chiller energy consumption met by renewable resources will be more costeffective and better at utilizing electricity from renewable energy resources than a system without thermal storage. These results suggest that widespread implementation of CTES systems may assist utilities in reaching their renewable penetration targets. [ABSTRACT FROM AUTHOR]