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In this paper, experimental and analytical studies of the energy consumption of rolling stocks in real operational conditions have been carried out. The Human factor, which significantly affects the consumption and recuperation of electrical energy, is minimized, as well as the influence of the railway profile. The measurements provide data on the energy consumption and on the total energy recuperated to the traction grid. The main indicators used in the analysis of the energy consumption have been calculated: relative operating energy consumption for acceleration and traction, relative energy recuperated to the traction grid during regenerative braking and relative net energy consumption. A comparative analysis of the energy indicators in terms of energy consumption with on and off air conditioning systems of the studied trains has been done. Digitization of the results has been made by two approaches – depending on the time range (peak, off-peak and night schedule) and the specifics of the route (the distance traveled). Recommendations have been done in various aspects in order to increase the efficiency of transport and optimize energy consumption. [ABSTRACT FROM AUTHOR]

The paper presents an analysis linked to sustainable energy alternatives in terms of the use of refrigerants in air conditioning equipment, with the aim of achieving compliance with the energy agreements that will allow avoiding and reducing the risk of pollutant emissions into the atmosphere, saving energy, and contributing to more efficient methods in this equipment. A bibliographical analysis was carried out to contextualize the research, in addition to the experimental method through systematic observation in the reconversion processes, in this context, measurements of the experimentation carried out were taken, in addition to carrying out different tests to obtain the desired results. The conversion processes were evaluated as an alternative to the substitution of R-22, through the use of R-290, which resulted in a decrease in condensation pressure between 4 and 6%, a decrease in pressure drops between 13 to 19% in the condenser, and between 24 and 43% in the evaporator, contributing to a 6 to 10% decrease in the demanded power, directly affecting the energy consumption of the equipment, resulting in a decrease of the cooling capacity between 5 and 8%, this being insignificant for premises with commercial and domestic use. [ABSTRACT FROM AUTHOR]

During the past almost two decades, the European Union launched and systematically updated Directives that aim to keep under control the use of energy in buildings. In this context, the "Strategy 20-20-20" (launched in January 2005), aimed to reduce greenhouse gases by 2020 with 20% and on the other hand, to increase the use of renewable energy consumption by 20%, in an effort to ensure the improvement of energy efficiency by 20%. It was followed in 2010 by the Energy Performance of Buildings Directive - that was revised in 2018 - and by the Energy Efficiency Directive in 2012, amended in 2019. Furthermore, in December 2021, the Commission proposed a revision of the Energy Performance of Buildings Directive, that sets new and ambitious targets regarding the buildings - either new or old - that match the provisions and expectation of the European Green Deal. "As of 2021, all new buildings must be nearly zero-energy buildings (NZEB) and since 2019, all new public buildings should be NZEB. When a building is sold or rented, energy performance certificates must be issued and inspection schemes for heating and air conditioning systems must be established" is stated on the Energy page of the site of the European Commission. However, as strange as it may seem, preoccupations for a fair energy management is probably almost as old as mankind as the building is the product with the longest life span: we have millennial buildings that not only stand but are still functioning. It was not a calculation or a direction that designed the buildings, it was the genius of architects. While not denying the political will and the strategies that it brings forth, it must be emphasized that energy efficient buildings were created long before the need to measure the building performance from the point of view of the energy it uses. And, as one of the greatest architects of the XX-th Century said "Architecture is the will of an epoch translated into space" (Ludwig Mies van der Rohe). And this epoch has the technological means of producing energy from alternative resources that can be embedded in building products. Hence, why not use them?! As means not as targets, in order for the building to continue to fulfil the Vitruvian triade: firmitas - utilitas - venustas (structural strength - utility - beauty). The paper is a plea for the prevalence of the architectural concept over rigid quantitative measures of energy efficiency. [ABSTRACT FROM AUTHOR]

During the past almost two decades, the European Union launched and systematically updated Directives that aim to keep under control the use of energy in buildings. In this context, the "Strategy 20-20-20" (launched in January 2005), aimed to reduce greenhouse gases by 2020 with 20% and on the other hand, to increase the use of renewable energy consumption by 20%, in an effort to ensure the improvement of energy efficiency by 20%. It was followed in 2010 by the Energy Performance of Buildings Directive - that was revised in 2018 - and by the Energy Efficiency Directive in 2012, amended in 2019. Furthermore, in December 2021, the Commission proposed a revision of the Energy Performance of Buildings Directive, that sets new and ambitious targets regarding the buildings - either new or old - that match the provisions and expectation of the European Green Deal. "As of 2021, all new buildings must be nearly zero-energy buildings (NZEB) and since 2019, all new public buildings should be NZEB. When a building is sold or rented, energy performance certificates must be issued and inspection schemes for heating and air conditioning systems must be established" is stated on the Energy page of the site of the European Commission. However, as strange as it may seem, preoccupations for a fair energy management is probably almost as old as mankind as the building is the product with the longest life span: we have millennial buildings that not only stand but are still functioning. It was not a calculation or a direction that designed the buildings, it was the genius of architects. While not denying the political will and the strategies that it brings forth, it must be emphasized that energy efficient buildings were created long before the need to measure the building performance from the point of view of the energy it uses. And, as one of the greatest architects of the XX-th Century said "Architecture is the will of an epoch translated into space" (Ludwig Mies van der Rohe). And this epoch has the technological means of producing energy from alternative resources that can be embedded in building products. Hence, why not use them?! As means not as targets, in order for the building to continue to fulfil the Vitruvian triade: firmitas - utilitas - venustas (structural strength - utility - beauty). The paper is a plea for the prevalence of the architectural concept over rigid quantitative measures of energy efficiency. [ABSTRACT FROM AUTHOR]

Residential air conditioning (AC) systems commonly use R-410A refrigerant for the new systems. The R-410A refrigerant has high global warming potential (GWP 100 years) of 2100 and it is not environmentally friendly. Moreover, energy consumption of AC systems also indirectly contributes to the GWP. Thus, energy performance of AC system becomes important. This paper aims to investigate seasonal energy performance of residential AC system using R-32 as refrigerant. R-32 has much lower impact to the environment compared to R-410A. The investigation applied a thermodynamic simulation using EES (Engineering Equation Solver) distributable program. The energy performances of the AC system were evaluated in one year based on Bali-Indonesia weather conditions. The performance evaluations include power and energy consumption, coefficient of performance, and seasonal energy efficiency ratio (SEER). For comparison analysis, the investigation was also performed on AC system using R-410A. The results indicated that the AC system using R-32 could provide better seasonal energy performance than a such system using R-410A. Therefore, R-32 becomes supplementary promising refrigerant for residential applications. [ABSTRACT FROM AUTHOR]

In past several years, due to technology advancements, the costs of variable speed drives have come down sharply allowing the widespread applications of variable speed devices in building air-conditioning systems. This article presents the case study on application level of variable speed drives to the components of the air-conditioning system (VAV system) installed in Vivekanand Lecture Theatre Complex (VLTC) at MNIT Jaipur, India. After incorporating the variable speed drives to the air conditioning system, the proposed case energy performance index has been compared with the standard energy performance indexes of Energy Conservation Building Codes 2017(ECBC, ECBC+ and Super ECBC), developed by the ministry of power and Bureau of Energy Efficiency(BEE), India. The study of Hartman research paper on variable speed chiller plants has been used to learn existing algorithm for developing new operating strategies. Simulations are performed on EnergyPlusV8.8.0 (an energy analysis simulation program) for more than dozens of cases by making the variable a single and multiple combinations of HVAC equipment (AHU, Cooling Tower, Chiller, Pumps). The results show that the application of variable speed drives improved the performance of the air conditioning system substantially. At an average, the energy consumption of all variable chiller plant decreased by 40-45% compared to a constant speed chiller plant. All-variable speed chiller plant operating strategies have been developed based on the tailored specific performance characteristics of variable speed chillers and the variable flow characteristics of condenser pumps and cooling towers. The specific component-wise energy performance improvement after the incorporation of variable drives and ECBC compliance check for the proposed case has been presented in this paper. [ABSTRACT FROM AUTHOR]

Following the energy strategy until 2035 of the Russian Federation, obsolete generation facilities are replaced with new promising combined-cycle power units with higher energy efficiency indicators. The difficulties of operating combined-cycle power units, particularly gas turbine units, are primarily related to the working fluid preparation quality. This article discusses the elaborate practice of the air supplied to the compressor, including its cooling and filtration. The paper presents an engineering solution for the technical re-equipment of an integrated air purifier by installing panels for the air's evaporative cooling. The porous structure of the panel material also allows for air filtration. The article presents the dependence of the power of a gas turbine installation on the temperature of the outdoor air in the climatic conditions of the Republic of Tatarstan (Russia). The economic effect of introducing the proposed technology is calculated, which is associated with eliminating lost profits from the under-development of electric energy and the quality of preparation of the working fluid for a gas turbine installation. [ABSTRACT FROM AUTHOR]

Residential air conditioning equipment has gained in public interest, primarily due to its huge energy consumption. Both in the US and Indonesia, this resulted in increased minimum efficiency standards. Manufacturers adhere to these standards through increased coil surface area, equipment size, and air flowrates for a given cooling capacity. While this has indeed reduced environmental footprint it also has led to issues for the testing of units. Increased indoor air handling unit height leads to conflicts between dictated inlet and outlet duct length and available total height of capital-intensive legacy testing facilities. This paper describes experiments conducted to evaluate the effects of changes in inlet ductwork configuration to the fan performance and highlights some of the constraints applicable to units with up-to-date electronically commutated fans. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation on the system performance of a residential air conditioner using condensate as a compressor discharge cooler. The condensate is water produced by the evaporator surfaces. The use of condensate is to reduce the energy consumption and improve the performance of the air conditioning system. The experimental investigation has been carried out on a split-type air conditioner with cooling capacity of 2.5 kW. The utilization of condensate as a discharge cooler decreased the compressor discharge pressure and consequently, reduced the compressor power consumption by 6.3%. In addition, the effect of the decrease in the compressor discharge pressure resulted in the decrement in the temperature of condenser outlet by 2.2°C. The decrease in temperature of condenser oulet leads to the increment in the subcooling and increases in the cooling capacity. [ABSTRACT FROM AUTHOR]

This paper presents the comparative experimental results of an automotive air conditioning (AAC) system charged with refrigerants R1234yf and R134a which were analyzed to find the effect of increasing ambient temperature using energy and exergy-based approaches. The urgencies for such investigation are due to the demand of finding refrigerant both satisfy the performance and also compatible with Kyoto Protocol and EU f-gas regulation. For this aim, a bench-top experimental AAC system was constructed and tested at four different compressor speeds, namely 1000, 1500, 2000, and 2500 rpm. For each compressor speed, the temperatures of the air streams at the inlets of the inside duct was 30 °C and varies the outside duct, i.e. Tcond,ai, of 30, 35, and 40°C. It was revealed that the AAC system with R1234yf yield comparative performances shown by the higher mass flow rate, comparably less cooling capacity and COP than that of with R134a. The mass flow rates and power absorbed in the compressor get higher as Tcond,ai increase. The biggest contributor to the total exergy destruction of the system is always the compressor and the heat exchangers, i.e. evaporator and condenser, respectively. Thus, in order to improve the system performance, those components should be enhanced. [ABSTRACT FROM AUTHOR]

The wind velocity plays a crucial role in the operation characteristic of indirect cooling tower. In this paper a 2×330MW vertical arrangement indirect air-cooled system was taken as research object, and numerical simulation method was used to analyze the relative influence of the wind speed, ranging from 4m/s to 18m/s, on the outlet water temperature of cooling tower, the outlet air temperature of radiator, the facing wind speed of the fan segment and on the outlet air speed of the cooling tower. The result shows that the impact of the natural wind speed on the cooling tower efficiency varies greatly and this impact increases as the wind speed increases. [ABSTRACT FROM AUTHOR]