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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]

Pressures on building designers are rapidly shifting as renewable energy dominates new supply, as the electricity end-use consumer becomes more integrated into the energy supply structure, and as buildings become increasingly needed to shelter in place. Features of this new generation of standard design include thermal resiliency to better ensure occupant safety, comfort, and health in power outages, buildings that can operate with low or no greenhouse gas emissions, and systems that can interact with electricity grids increasingly dependent on variable renewable power. The rapid pace of change dictates that codes and standards should be developed that can ensure that these future-proofing design are widely vetted and documented to guide standard practice construction. Codes and standards can do that. This paper will consider how work underway in ASHRAE Standards 189.1, 227p, 228p and IEEE Standard 1547 as well as in market facing programs such as Passive House, is beginning to standardize some of these key changes in design practice. The paper then proposes that IECC and ASHRAE 90.1 are uniquely positioned for comprehensive regulatory strategies that engage these and other standards to meet the new challenges. By establishing measures for new construction and existing buildings in the nation’s model energy codes, these stalwart documents can ensure that buildings are designed for a paradigm most relevant to their use: not relying on the decades old energy code paradigm now on the books, but rather looking forward to meet the needs of owners, occupants, and the communities in which they are located. [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]

Aligning with the United Nations '2030' Agenda for Sustainable Development that aims to increase the share of renewable energy in the global energy mix, the usage of Solar Domestic Water Heating (SDWH) systems for residential and industrial-scale increased dramatically during the last decade. Although the renewable energy sources are abundant and become more cost effective with time, the majority of these sources are intermittent and uncontrollable which create a gap between the energy demand and supply. Accordingly, integrating an efficient thermal energy storage method to these SDWH systems is pivotal to achieve the sustainable development goals. The most common thermal storage technique is sensible energy storage by using large water tanks, however, this technique discloses some major drawbacks in terms of space and weight. On the other hand, the latent energy storage techniques based on Phase Change Materials (PCM) have several advantages in terms of size, cost, thermal performance and chemical stability. The current study is part of a project dedicated to design a tankless SDWH system that benefits from the advantages of the PCM and overcome the drawbacks of the sensible water storage tanks. The proposed tankless SDWH is achieved through incorporating PCM materials in a conventional evacuated tube solar collector. The aim of this paper is to numerically investigate the thermal performance of a single evacuated tube filled with Paraffin wax using ANSYS FLUENT 16.5. Specifically, a CFD model includes the enthalpy-porosity formulation and the melting/solidification model is used to simulate the phase change cycles into the proposed compact SDWH. The main outcome of this research is a trustworthy model that will be used to study the effect of several factors include the design parameters, operation condition on system performance. Subsequently the validated model will be used as a design tool to simulate and optimize the system in thermal and economical terms without the limits of the experimental studies. [ABSTRACT FROM AUTHOR]