Electric and hybrid vehicles environmental control subsystem study

An environmental control subsystem (ECS) in the passenger compartment of electric and hybrid vehicles is studied. Various methods of obtaining the desired temperature control for the battery pack is also studied. The functional requirements of ECS equipment is defined. Following categorization by methodology, technology availability and risk, all viable ECS concepts are evaluated. Each is assessed independently for benefits versus risk, as well as for its feasibility to short, intermediate and long term product development. Selection of the preferred concept is made against these requirements, as well as the study's major goal of providing safe, highly efficient and thermally confortable ECS equipment

TRANSIENT PERFORMANCE EVALUATION OF AUTOMOTIVE SECONDARY LOOP SYSTEMS

Automotive air-conditioning is a high impact technology where improvements in energy consumption and environmental performance can make a significant difference in fuel efficiency and comfort. The mandatory phase out of R134a as refrigerant in the European Union has set the stage for new systems and alternative refrigerants. While some of these refrigerants, such as R152a or R290, have a low Global Warming Potential, their flammability requires secondary loop systems to be used. The added thermal mass of such systems may increase power consumption and delay cool down while benefitting thermal comfort during start/stop operation. The recent revival of electric vehicles, as well as the associated focus on air-conditioning energy consumption, provides new challenges and opportunities. This research focuses on the performance evaluation of refrigerants R152a and R290 during transient operation in secondary loop systems, quantification of thermal storage benefits for start/stop operation, and investigation of energy saving potentials in electric vehicles through the use of advanced air-conditioning system controls and cabin preconditioning. A test facility was built to dynamically test secondary loop systems over a wide range of pull down conditions and drive cycles using a passenger cabin model and associated controls. It was shown that R290 is a viable alternative in secondary loop systems and system performance may be on par or better compared to R134a direct expansion systems. The preservation of cooling capacity and thermal comfort during off-cycle periods were quantified for a secondary loop system, as well as a combined ice storage system. System efficiency increases with longer off-cycle periods compared to direct expansion systems. Advanced compressor control strategies and the use of cabin preconditioning can make use of this characteristic and improve energy efficiency by more than 50%. Ice storage may be used in combination with cabin preconditioning to preserve comfort for an extended driving time with reduced use of the vapor compression cycle. A Modelica model of the secondary loop system was developed and validated with experimental data. The model enables dynamic simulation of pull-down and drive cycle scenarios and was used to study the effects of coolant volume and coolant concentration on transient performance

Energy: A continuing bibliography with indexes, issue 19

A bibliographical list of 1339 reports, articles, and other documents introduced into the NASA scientific and technical information system from July 1, 1978 through September 30, 1978 are presented

NASA Thesaurus. Volume 1: Hierarchical listing

There are 16,713 postable terms and 3,716 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary

Energy. A continuing bibliography with indexes, issue 26, 1 April - 30 June 1980

This bibliography lists 1134 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System from April 1, 1980 through June 30, 1980

Energy: A continuing bibliography with indexes, issue 12

This bibliography lists 584 reports, articles, and other documents introduced into the NASA scientific and technical information system from October 1, 1976 through December 31, 1976

NASA thesaurus. Volume 1: Hierarchical Listing

There are over 17,000 postable terms and nearly 4,000 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary and Volume 3 - Definitions

Study and comparison of different types of powered aircrafts for the future commercial aviation

These days commercial aviation is very important, it has a great influence on economy and social aspects. In 2019, IATA calculated that 65.5 million jobs in the world were created thanks to aviation and the total effect on the economy was about 2.7 billion euros. During 2020 and 2021, commercial aviation suffered due to the restrictions of the COVID-19 pandemic, even reaching extremes where some airlines had to fly without passengers in order to avoid losing their slots. Since the end of the year 2021 and the beginning of 2022, the commercial aircraft has recovered considerably and is now on the same figures as in 2019. Thanks to low-cost airlines, Europe and the United States are the regions with the highest volume of flights, but in countries like China and India, commercial aviation is expected to increase exponentially, especially due to the number of inhabitants in Asian countries. A short and medium haul commercial aircraft like the A320 usually burns an average of 2,500 kilos of fuel every hour. Around the world there are near 200,000 flights every day, therefore the amount of burnt fuel is exorbitant. Also, knowing that 3.16 kilograms of CO2 are generated for 1 kilogram of fuel, we can conclude that we have a major sustainability problem because of the tons of emissions that are emitted daily. The main objective of this project is the study of new technologies that are capable of propelling aircrafts for commercial aviation while emitting fewer or zero emissions. More specifically, possible aircrafts powered by sustainable fuel, solar energy, electric energy, nuclear energy,hydrogen and electric plasma have been studied and evaluated. In addition, a comparison has been made of the characteristicsof each technology and the forecast on which technology is the most suitable to replace fossil fuels and in what year it may appear.Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminan

Energy: A continuing bibliography with indexes

This bibliography lists 1169 reports, articles, and other documents introduced into the NASA scientific and technical information system from January 1, 1983 through March 31, 1983

Energy: A continuing bibliography with indexes

This bibliography lists 1096 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System from April 1, 1979 through June 30, 1979