scholarly journals Hybrid Cascade Heat Pump and Thermal-Electric Energy Storage System for Residential Buildings: Experimental Testing and Performance Analysis

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2580
Author(s):  
Valeria Palomba ◽  
Antonino Bonanno ◽  
Giovanni Brunaccini ◽  
Davide Aloisio ◽  
Francesco Sergi ◽  
...  
Keyword(s):  
Heat Pump ◽  
Energy Demand ◽  
Experimental Testing ◽  
Residential Buildings ◽  
Storage System ◽  
Electric Energy ◽  
Energy Storage System ◽  
Primary Energy ◽  
Electric Energy Storage ◽  
Primary Energy Demand

The need for innovative heating and cooling systems to decarbonize the building sector is widely recognized. It is especially important to increase the share of renewables at building level by maximizing self-consumption and reducing the primary energy demand. Accordingly, in the present paper, the results on a wide experimental campaign on a hybrid system are discussed. The system included a sorption module working as the topping cycle in a cascade configuration with a DC-driven vapor compression heat pump. A three-fluids heat exchanger with a phase change material (PCM), i.e., RT4 with nominal melting temperature of 4 °C, was installed on the evaporator side of the heat pump, for simultaneous operation as thermal storage and heat pumping purposes. The heat pump was connected to a DC-bus that included PV connection and electricity storage (batteries). Results showed that the energy efficiency of the heat pump in cascade operation was double compared to compression-only configuration and that, when simultaneously charging and discharging the latent storage in cascade configuration, no penalization in terms of efficiency compared to the compression-only configuration was measured. The self-sufficiency of the system was evaluated for three reference weeks in summer conditions of Athens climate and it was found that up to 100% of the electricity needed to drive the system could be self-produced for a modest cooling demand and up to 67% for the warmer conditions with high cooling demand.

scholarly journals Operating conditions of electric energy storage system in DC traction power supply for single-track sections of railways

2021 ◽  
Vol 80 (4) ◽  
pp. 216-224
Author(s):  
V. L. Nezevak
Keyword(s):  
Energy Storage ◽  
Power Supply ◽  
Storage System ◽  
Electric Energy ◽  
Energy Storage System ◽  
Operating Conditions ◽  
Electric Energy Storage ◽  
Electric Energy Storage System ◽  
Traction Power Supply ◽  
Traction Power

Considered are the issues of using electric energy storage system in the traction power supply of direct current of a single-track section. An overview of the main directions of domestic and foreign research in the field of using these systems to increase the capacity and energy efficiency of power supply systems is given. Modeling the operation of energy storage system in traction power supply is based on the calculation of load graphs within the boundaries of inter-substation zones, formed depending on the conditions for the passage of trains and traction load on the railway section. The main provisions of the method for choosing locations and determining the parameters of energy storage system in traction power supply are considered. On the example of one of the inter-substation zones of the Sverdlovsk railway, the influence of the power of the active sectioning station on the increase in the minimum voltage level at the pantograph of the electric rolling stock is shown. The graphs of the degree of charge and the corresponding frequency distributions are given, which make it possible to evaluate the operating conditions of the electric energy storage system depending on the conditions for the formation of the traction load, as well as the graphs of the load of the electric energy storage system and the corresponding charging characteristics for the operating conditions at the sectioning post. On the example of the section under consideration, the dependence of the discharge depth of the electric energy storage system on the nominal energy intensity is shown. Based on the results of calculations, an evaluation was made of the options for passing train batches in the even and odd direction in comparison with the schedule of the performed train operation. The range of variation of the nominal values of power and energy intensity of the electric energy storage system is obtained. Comparison of the accumulation system parameters for single- and double-track sections of railways, including those with a predominance of passenger traffic, is carried out.

Second Law Analysis of an Energy Storage System Consisting of an Electrolysis Plant and the Graz Cycle With Internal H2/O2 Combustion

2019 ◽  
Author(s):  
Simeon Dybe ◽  
Tom Tanneberger ◽  
Panagiotis Stathopoulos
Keyword(s):  
Energy Storage ◽  
Power Plants ◽  
Storage System ◽  
Electric Energy ◽  
Energy Storage System ◽  
Working Fluid ◽  
Energetic Efficiency ◽  
Second Law ◽  
Electric Energy Storage ◽  
Second Law Analysis

Abstract The expansion of renewable energy generation must go hand in hand with measures for reliable energy supply and energy storage. A combination of hydrogen and oxygen as storing media provided from electrolysis at high pressure and zero emission power plants is a very promising option. The Graz cycle is an oxy-fuel combined power cycle that can operate with internal H2/O2 combustion and steam as working fluid. It offers thermal efficiencies up to 68.5% (LHV). This work applies a second law analysis to the Graz cycle and determines its exergetic efficiency. Exergy destruction is broken down to the cycle’s components thus providing insights on the location and magnitude of the cycle’s inefficiencies. A sensitivity analysis identifies the cycle’s exergetic and energetic efficiency as a function of representative parameters, offering an approach for future improvements. The combination of the cycle with an electrolysis plant is subsequently analyzed as an electric energy storage system. The round trip efficiency of the storage and back conversion system is computed by taking into account the additional compression of the reactants. As part of this analysis, the effect of the electrolyzer’s operational pressure is studied by comparing several commercial electrolyzers.

Novel graphite/TiO2 electrochemical cells as a safe electric energy storage system

2010 ◽  
Vol 55 (24) ◽  
pp. 7305-7309 ◽  
Author(s):  
Arjun Kumar Thapa ◽  
Gumjae Park ◽  
Hiroyoshi Nakamura ◽  
Tatsumi Ishihara ◽  
Nariaki Moriyama ◽  
...  
Keyword(s):  
Energy Storage ◽  
Storage System ◽  
Electric Energy ◽  
Energy Storage System ◽  
Electrochemical Cells ◽  
Electric Energy Storage ◽  
Electric Energy Storage System
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