“energy”Search All-EnPress Publisher LLC.

Jul 20, 2022

Energy saving analysis of photovoltaic roof based on MATLAB

One-dimensional unsteady theoretical models of three different photovoltaic module installation modes are established. Through MATLAB modeling and simulation, the influence of photovoltaic modules on roof heat transfer in different layout modes is compared. Comparing with ordinary roof, the shading effect of photovoltaic roof in summer and heat preservation effect in winter was analyzed. The results show that the PV roof layout with ventilation channel is better in summer. The proof layout with closed flow channel is better in winter.

Abstract

Download PDF(1.15M)

XML

1

48

Jan 18, 2022

The comparable study of isoelectronic-bodies of single-walled B/N nanotubes

The structure, thermodynamic stability, ionization potential (IP) and electron affinity (EA) energy level difference (E_g) and tension of lowest unoccupied orbit (LUMO) and highest occupied orbit (HOMO) of armchair single wall carbon nanotubes (C-NTs), BN hybrid carbon nanotubes (BC₂N-NTs) and all BN nanotubes (BN-NTs) were systematically studied with AM1 method in this paper. Calculation results show that when n value is constant, (n, n) C-NTs (n = 3,4,5,6) has the largest diameter and BN-NTs has the smallest diameter; (n, n) the values of E_g (HOMO-LUMO) and n of C-NTs and BC₂N-NTs are related; POAV analysis shows that different hybrid atoms have different contributions to the hybrid mode of nanotube atoms and the tension of nanotubes.

Abstract

Download PDF(355.38KB)

XML

1

67

Nov 28, 2021

Thermo-exergetic evaluation of a compact pyrotubular steam generator

One of the most important variables to know how efficient a thermal machine is the exergy. In practice, it is one of the least controlled variables. In this research, a thermal exergy study was carried out in a compact pyrotubular steam generator. To achieve this, an energy mass balance and entropy balance were carried out. The energy balance was carried out by direct and indirect methods. The percentages of the exergies of each working substance in the process are specified. The energy yield by the direct method was 0.901 and by the indirect method was 0.882, since each method has its role in the energy analysis. The irreversibilities in the process were 26%. The exergetic efficiency was 0.39, conditioned by a complete combustion in the hearth. It was demonstrated that the steam generator for the real operating conditions is oversized.

Abstract

Download PDF(355.54KB)

XML

2

56

Nov 2, 2021

Dynamics of Bianchi type-V anisotropic dark energy cosmological model in a scale covariant theory of gravitation

This paper is devoted to the discussion of dynamical properties of anisotropic dark energy cosmological model of the universe in a Bianchi type-V space time in the framework of scale covariant theory of gravitation formulated by Canuto et al.(phys.Rev.Lett.39:429,1977).A dark energy cosmological model is presented by solving the field equations of this theory by using some physically viable conditions. The dynamics of the model is studied by computing the cosmological parameters, dark energy density, equation of state(EoS) parameter, skewness parameters, deceleration parameter and the jerk parameter. This being a scalar field model gives us the quintessence model of the universe which describes a significant dark energy candidate of our accelerating universe. All the physical quantities discussed are in agreement with the recent cosmological observations.

Abstract

Download PDF(274.40KB)

XML

1

54

Aug 9, 2021

Performance analysis of ground source heat pump system under low load rate

Taking a demonstration project of a ground source heat pump system under karst geological conditions in Guilin as the research object, based on the measured data under operating conditions in a typical season, and sorted according to the importance of influencing factors, this paper mainly studies the influence of system at very low load rate and unit load rate on the operation effect of ground source heat pump system. The research results show that the ground source heat pump system is in good operating condition when the system load rate is lower than 30.00% and the unit load rate is higher than 80.00% in typical seasons, and the proportion of power consumption of units and pumps meets the energy consumption requirements of transmission and distribution system. During the operation of the heat pump unit in July, the average refrigeration performance coefficient of the unit is 4.48, and the average refrigeration energy efficiency ratio of the system is 3.59; during the operation in January, the average heating performance coefficient of the unit is 4.26, and the average heating energy efficiency ratio of the system is 3.32; the energy saving rate in summer and winter is 30.72% and 35.93%, respectively. The energy-saving effect of the ground source heat pump system is remarkable, and it is worth popularizing and applying in Guilin.

Abstract

Download PDF(1.22M)

XML

1