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Malhotra, Mini

Publications and source records attributed to Malhotra, Mini.

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Impact analysis of heating electrification in US buildings with geothermal heat pumps

Few studies have investigated the impacts of large-scale deployment of geothermal heat pumps (GHPs, also called ground source heat pumps) on the electric grid. GHPs utilize the ground as a heat source to warm buildings more efficiently than other space-heating systems. The coupling with the ground offers seasonal thermal storage so that GHPs can also cool buildings in summer more efficiently than other space-cooling systems. This study simulated the performance of GHP systems for various commercial and residential buildings in 15 climate zones in the United States. Combined with the latest End-Use Load Profiles of the US building stock and grid modeling, this study aims to assess the impacts of a national deployment of GHP systems on the US electric grid in terms of energy consumption, emissions, and operational resilience. The preliminary results show that the GHP deployment can save 429 billion kWh of electricity (a 19% reduction from baseline) and reduce carbon emissions by 496 million tons per year (a 31 % reduction from baseline). A geographical view of the results indicates that retrofitting existing HVAC systems with new GHP systems can lead to further reductions in annual electricity consumption and peak electricity demand in the southern regions of the United States than in other parts of the country. On the other hand, GHP retrofits result in higher percentages of site energy savings and carbon emission reduction in the north (cold climates) than in the south (warm climates).

Liu, Xiaobing↗
DOE OSTI2022

Development of a web-based screening tool for ground source heat pump applications

Ground source heat pump (GSHP) technology has great potential to help the nation meet its energy and decarbonization goals, but several barriers hinder the wide application of GSHP. Important barriers include the lack of a coherent toolset for analyzing the technical feasibility and economic viability of the GSHP application. The current design and analysis methods are ineffective and require significant expertise to apply. Although building energy modeling is increasingly important in designing buildings, the tools for GSHP modeling and simulation are lacking. A web-based free-to-use tool is being developed for quick techno-economic analysis of GSHP applications in nearly any building in the United States. This tool is enabled by improvements in the calculation methodology to allow rapid sizing of borehole configurations that provide significant cost savings. The screening tool currently uses US Department of Energy (DOE) prototype building models and an extended g-function library to size ground heat exchangers and simulate the performance of GSHP systems. The team is integrating with DOE's Oak Ridge National Laboratory's AutoBEM program to automatically create a building model based on user inputs. This paper introduces the structure, components, features, and results of the web-based screening tool for GSHP applications. Future directions for further developing the tool are also discussed.

Liu, Xiaobing↗
DOE OSTI2022

A geo-visual analysis for exploring the socioeconomic benefits of the heating electrification using geothermal energy

In parallel to population growth and climate change, the rapid pace of urbanization worldwide has led to an enormous increase in energy demand and costs in urban areas. The subsequent energy burden has become an increasing concern for many households in the U.S. Previous studies have revealed that geothermal resources can effectively lower the electricity demand and carbon emissions in large cities. In this paper, we focus on the socioeconomic impacts of geothermal energy on urban systems by presenting an interactive visual analytics dashboard. The dashboard allows urban planners to spatially examine geothermal energy's practical benefits on energy affordability, urban livability, and resilience across the U.S. We compiled a list of socioeconomic metrics by integrating the simulation results from multiple geothermal and building models with multi-domain urban datasets (socioeconomic, demographic, and electricity utility). These metrics are created to characterize the benefits of the heating electrification of buildings using Geothermal Heat Pumps (GHP) for lowering the energy burden of middle-and low-income households nationwide. The visual dashboard employs a combination of multivariate, glyph-based, and geospatial visualization to reveal the variability and patterns in our metrics. We present a pilot study to demonstrate the GHPs' potential as a renewable and affordable solution for increasing the economic and energy grid resilience in U.S cities.

Xu, Haowen↗
DOE OSTI2022

Prototype Courthouse Building Energy Model: Building Characteristics and Energy Simulation Results

To coordinate commercial building energy research activities, the US Department of Energy uses a suite of commercial prototype building models, which includes 16 building types and covers 80% of US commercial floorspace. Efforts are underway to expand this suite by developing prototype models for additional building types, including a courthouse. Informed by building design guides, databases, documented projects, and personal communication with courthouse design experts, a 3-story, 4-courtroom, 69,324 ft 2 building was considered as the prototype courthouse to represent an average-sized courthouse in the United States. This report documents the building and system characteristics of the prototype courthouse model combined with climate-specific and construction vintage–specific requirements for the building envelope and systems from ASHRAE Standard 90.1. The energy simulation results are presented for 4 construction vintages (2004, 2007, 2010, and 2013) and 15 ASHRAE climate zones. To verify the energy simulation results, energy use statistics of existing courthouses from different building database are also presented. Based on the simulated energy use, the site energy use intensity of the prototype courthouse ranged from 45 to 159 kBtu/ft 2 compared with the average energy use intensity of 94.7 kBtu/ft 2 for the courthouse building type in the 2012 Commercial Building Energy Consumption Survey (CBECS) Data.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Prototype College Building Energy Model: Building Characteristics and Energy Simulation Results

The US Department of Energy supports the development of commercial building energy codes and standards. To support commercial building energy research activities and the development of commercial building energy codes and standards, continuous efforts have been made to convert 16 prototype building models, which cover 80% of US commercial building floor space, to OpenStudio prototype buildings. Additionally, the suite of prototype building models was expanded to include the addition of new building prototype models (e.g., courthouse, college building). Multiple sources, including databases, documented projects, and personal communications, were used to define the prototype college building, and a 4-story with 69,063 ft 2 building was considered as the prototype college building to represent an average-sized college building in the United States. To represent realistic occupancy schedules and increase the granularity of information, actual class reservation schedules were collected and used. This report documents the building and system characteristics of the prototype college building model combined with climate-specific and construction vintage–specific requirements for the building envelope and systems from ASHRAE Standard 90.1. The energy simulation results are presented for 4 construction vintages (2004, 2007, 2010, and 2013) and 15 ASHRAE climate zones. The site energy use intensity of the college building was compared with 2012 Commercial Building Energy Consumption Survey (CBECS) and ENERGY STAR data to verify the simulation results. The site energy use intensity of the college building ranged from 60 to 202.4 kBtu/ft 2 , and compared with the energy use intensities of Commercial Building Energy Consumption Survey (122.9 kBtu/ft 2 ) and ENERGY STAR (84.3 kBtu/ft 2 ) data, the prototype college building results are in a reasonable range.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Mine Water Use, Treatment, and Reuse in the United States: A Look at Current Industry Practices and Select Case Studies

Mining provides significant economic value while often impacting local water supplies and environments because of freshwater usage and waste disposal practices. In this paper we identify current practices in mine water, including how water is used in mining, influent and effluent water quality, treatment technologies, and end uses with the goal of informing future research on implementable, reliable, and cost-effective advanced water treatment in the mining sector. This study also reviews the available literature to broadly evaluate mining in the United States and performs a techno-economic assessment on water use and disposal for three detailed case studies applicable to lithium, uranium, and copper mines. These case studies highlight specific industry examples of distinct extraction methods, geographical regions, and mined commodities. Hypothetical scenarios based on case study baselines revealed potential impacts to mine water available for beneficial reuse through the use of novel water treatment technologies and alternate water management strategies. Finally, an assessment of national level impacts resulting from the reuse of treated mine source water is presented.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Opportunities and Challenges for Industrial Water Treatment and Reuse

As the impact of water scarcity in the United States (U.S.) continues to grow through the 21st century, it is critical to develop strategies to reduce water use and improve the security of water resources. One such strategy is to diversify the sources from which water is supplied. Industrial withdrawals represent the fourth largest category of U.S. water use, the majority of which is sourced from fresh surface and groundwater. In this study, we critically explore the potential of industrial wastewater to serve as an alternative water resource through direct treatment and reuse. We begin by reviewing the state of the art of water use, treatment, and reuse across six representative industries: food and beverages, primary metals, pulp and paper, petroleum refining, chemicals, and data centers and campuses, highlighting key challenges and opportunities toward the expansion of reuse. We then employ a technoeconomic assessment of water treatment processes to analyze the capital investment, operating and maintenance costs, levelized cost of water, and electricity consumption of three specific industrial plants as case studies to better understand where research can promote impactful innovation. Finally, drawing together the results of our literature review and technoeconomic analyses, we provide a broad outlook on the future of industrial water reuse and discuss strategies for its expansion.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Plant Water Profiler: A Water Balance and True Cost of Water Calculator for Manufacturing Plants

As the uncertainty of a sustained water supply, regulatory constraints, competition among end users, and public scrutiny increases, a growing number of manufacturing sectors are adapting to current and emerging water-related risks by optimizing productivity and reducing waste. As a step toward increasing water use efficiency and making informed business decisions, corporations must make an effort to understand and track their water demands, losses, and costs associated with each subsystem within their facilities. Manufacturers are often unaware of the “true cost of water” (i.e., the total costs associated with procurement, treatment, and consumption of water, and wastewater disposal), which reduces the visibility of the actual impact of water-saving measures. To help manufacturers account for water procurement and use in manufacturing operations, quantify the true cost of water, and identify potential areas for water and associated energy cost savings, an open access tool—Plant Water Profiler (PWP)—was developed. The tool is based on water mass balance analysis and has been adopted as the core analysis tool for plant water use assessments, Water In-Plant Training (Water INPLT), as part of the US Department of Energy’s Better Plants program. During three pilot INPLTs conducted in 2019 at three manufacturing facilities, the PWP tool allowed users to understand water flows within the facilities and provided additional capabilities to analyze their water use. This paper describes the methodology behind the PWP tool and its implementation through pilot Water INPLT trainings delivered in three manufacturing facilities in the United States. The three case studies demonstrate opportunities to improve water efficiency and reduce associated costs and the challenges encountered in three different manufacturing sectors.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Plant Water Profiler: A Tool for Understanding Water Use, Cost and Savings Potential for Manufacturing Plants

In the 1746 Poor Richard’s Almanack, Benjamin Franklin published “When the well’s dry, we know the worth of water” (Franklin, 1746); industrial water users have begun to see the truth in these words as they examine the potential and reality of water scarcity becoming a significant business risk. Through the authors’ interactions with manufacturers via the U.S. Department of Energy’s Better Plants program and Strategic Analysis projects, they realized that manufacturing facilities often do not fully understand the risks to the water supply and the consequential risks to their business. The authors’ also noticed that many facilities do not know how their water is used (baselining), how they compare with their peers (benchmarking), the actual cost impacts of water use (true cost of water), and potential areas for water savings. This results in a lack of motivation and ability to identify and implement effective water-efficiency measures.The Plant Water Profiler Tool (PWP) was created to help manufacturing plant management address these issues by identifying and accounting for water use in manufacturing operations, helping determine the true cost of water, and providing some high-level estimates for peer comparison. The PWP uses a water mass balance and common engineering equations to estimate water use by each of the facility’s systems (e.g., differentiating process water use from cooling and restroom water use), even when no submetering data is available. This new tool also helps users identify possible areas for water savings and associated water and energy cost savings, making it a potentially useful resource for corporations conducting water assessments. Additionally, governments and private organizations can use the methodology behind this tool to design a survey to help build a database of industrial water use. This paper and corresponding presentation provide an overview of current industrial water use practices and tools, as well as the value of determining the true cost of water. It also briefly describes the methodology behind the tool, then focuses on its functionality through an industrial case study and lessons learned from implementing the case study.

Armstrong, Kristina O.↗
DOE OSTI2019

A Process for Defining Prototype Building Models: Courthouse Case Study for U.S. Commercial Energy

Buildings currently consume 36% of the world’s energy and contribute nearly 40% of CO 2 emissions. Many countries desire to generate virtual models of their nation’s buildings in order to coordinate research activities and inform market opportunities for a more sustainable built environment. The United States Department of Energy uses a suite of Commercial Prototype Building Models, which currently includes 16 building types and covers 80% of US commercial floorspace. Efforts are underway to expand this suite by developing prototype models for additional building types. In this paper, we outline a systematic approach to defining the building, collecting relevant information and creating a flexible model while doing so in the pragmatic context of a courthouse building. Informed by building design guides, databases, documented projects and inputs from courthouse design experts, we define a small, 69,324 ft 2 (6440 m 2 ), four-courtroom, low-rise courthouse as the prototype to represent an average-size courthouse in the US. We present building characteristics relevant for energy model development and provide the rationale for their selection. These details combined with climate- and construction-vintage-specific requirements for the building envelope and systems from building standards will be used for developing the courthouse model for the Commercial Prototype Building Models suite. The comprehensive information presented will also guide model modification to capture the dynamics of smaller or larger courthouses more accurately for building or system size-specific research.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Furnace and Water Heater Venting Field Demonstration

A field demonstration was performed to evaluate the venting performance of the M&G DuraVent FasNSeal 80/90 venting system. The venting system uses a unique pipe within a pipe design to vent a condensing furnace and an natural-draft water heater, and can enable a condensing furnace to be installed in a home in which a condensing furnace could not otherwise be installed due to venting constraints. The field demonstration found that the FasNSeal 80/90 venting system successfully vented the orphaned water heater in each of the 16 demonstration homes and that the venting performance of the FasNSeal 80/90 venting system is generally comparable to the performance of venting systems initially installed in the 16 homes.

42 ENGINEERING↗
DOE OSTI2019

Study of optimal sizing for residential sorption heat pump system

Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water production in residential applications. This study considered a bivalent heating system consisting of a sorption heat pump and a condensing boiler, and focuses on the optimal heating capacity of each of these components relative to each other. Two bivalent systems were considered: one based on a solid chemisorption cycle (GDSHPA), and one based on a resorption cycle (GDSHPB). Simulations of year-round space heating loads for two single-family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) calculated. The sorption heat pump’s design heating capacity as a fraction of the bivalent system’s total heating capacity was varied from 0 to 100%. Results show that SGCOP was effectively constant for sorption heat pump design capacity greater than 41% of the peak bivalent GDSHPA design capacity in Minnesota, and 32% for GDSHPB. In New York, these values were 42% and 34% for GDSHPA and GDSHPB respectively. The payback period was also evaluated based on postulated sorption heat pump component costs. The fastest payback was achieved with sorption heat pump design capacity between 22 and 44%.

42 ENGINEERING↗
DOE OSTI2018

Multifamily Tool for Energy Audits (MulTEA) Engineering Manual (Version 1)

The Multifamily Tool for Energy Audits (MulTEA) is an energy audit tool designed to provide auditors with an improved energy simulation tool for multifamily buildings and an improved tool for identifying cost-effective energy-efficiency retrofit measures for multifamily buildings. MulTEA is designed specifically to help states and local weatherization agencies implement the Department of Energy (DOE) Weatherization Assistance Program. MulTEA was developed jointly by the Oak Ridge National Laboratory (ORNL) and the Lawrence Berkeley National Laboratory (LBNL). MulTEA is part of ORNL’s web-based Weatherization Assistant suite of audit tools (https://weatherization.ornl.gov/softwaredescription/). The energy calculation engine including the DOE- 2 simulation model and supplementary calculation modules is shared by MulTEA and LBNL’s Home Energy Saver pro (HESpro) (http://hespro.lbl.gov/pro/). On the ORNL side, the energy calculation engine is coupled with a user interface and output reporting capabilities based on Weatherization Assistance Program regulations and guidelines pertinent to MulTEA. On the LBNL side, the same engine will be used in HESpro to expand it to handle multifamily buildings. MulTEA is designed to address small and large multifamily buildings with decentralized and centralized heating, ventilation, and air-conditioning (HVAC) and domestic hot water (DHW) systems. Version 1 of MulTEA addresses small multifamily buildings with decentralized HVAC systems, and decentralized or centralized DHW systems. The capability to model large buildings and centralized HVAC systems will be incorporated in Version 2.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Domestic Dishwasher Simulated Energy Efficiency Evaluation Using Thermoelectric Heat Pump for Water Heating and Dish Drying

A quasi-steady state, heat and mass transfer lumped-capacitance model was developed to predict the energy consumption and drying performance of domestic dishwashers. A numerical finite element solution was applied, assuming that the following components could each be treated as a lumped thermal capacitance: dish load, tub, wash water, and air in tub. The model was used to predict the energy consumption savings of heating water using a thermoelectric heat pump that extracts heat from a thermal storage medium, and the drying performance of circulating tub air through the cold and then hot side of TE modules.

Abuheiba, Ahmad↗
DOE OSTI2018

Comparison Evaluations of VRF and RTU Systems Performance on Flexible Research Platform

The energy performance of a variable refrigerant flow (VRF) system was evaluated using an occupancy-emulated research building in the southeastern region of the United States. Full- and part-load performance of the VRF system in heating and cooling seasons was compared with a conventional rooftop unit (RTU) variable-air-volume system with electric resistance heating. During both the heating and cooling seasons, full- and part-load conditions (i.e., 100%, 75%, and 50% thermal loads) were maintained alternately for 2 to 3 days each, and the energy use, thermal conditions, and coefficient of performance (COP) for the RTU and VRF system were measured. During the cooling season, the VRF system had an average COP of 4.2, 3.9, and 3.7 compared with 3.1, 3.0, and 2.5 for the RTU system under 100%, 75%, and 50% load conditions and resulted in estimated energy savings of 30%, 37%, and 47%, respectively. Finally, during the heating season, the VRF system had an average COP ranging from 1.2 to 2.0, substantially higher than the COPs of the RTU system, and resulted in estimated energy savings of 51%, 47%, and 27% under the three load conditions, respectively.

42 ENGINEERING↗
DOE OSTI2018

Prototype Courthouse Building Energy Model: Building and System Characteristics

As part of the Department of Energy’s support of ANSI/ASHRAE/IES Standard 90.1 and the International Energy Conservation Code, researchers at Pacific Northwest National Laboratory apply a suite of prototype buildings covering 80% of the commercial building floor area in the United States for new construction. Efforts have begun to cover 90% of the commercial building floor area in the United States by developing prototype models for additional building types that include supermarket, laboratory, place of worship, public order and safety, and public assembly. “Courthouse” is a subcategory under the “Public Order and Safety” building type category defined by the Commercial Buildings Energy Consumption Survey (CBECS); other subcategories include police station, fire station, and detention and correctional facilities (i.e., jail, reformatory, or penitentiary). Oak Ridge National Laboratory used building design guides, databases, and documented courthouse projects, supplemented by personal communication with courthouse facility planning and design experts, to systematically conduct research on the courthouse building and system characteristics. This report documents this research and reports the building and system characteristics necessary for developing a Courthouse prototype building energy model to be included in the Commercial Building Prototype Model suite.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗