The low conversion efficiency of solar cells produces large amounts of thermal energy to the cells, and with an increase in the temperature of solar cells, their electrical efficiency decreases. Therefore, a hybrid photovoltaic thermal system improves the overall efficiency of the system by adding thermal equipment to the solar cell and removing excessive heat from these cells. In this paper, w...

the aim of this study is to find the optimal water pressure and percentage of supply vapour in the feed water heaters (fwhs) of steam power plants, such that they maximize the thermal efficiency of the rankine cycle within pre-specified values of minimum and maximum pressures of the thermodynamic cycle. thermal efficiency is defined as a function of unknown variables (fluid pressure and vapour ...

This paper aims at estimating the efficiency of hydroelectric power plants (renewable energy resources) and thermal power plant (non-renewable energy resources) in Iranian provinces. Data Envelopment Analysis (DEA) approaches is applied to estimate the efficiency. The network is modeled as a linear system with multiple inputs and one output. Fuel cost, labor force, operation cost are used as in...

heat and mass transfer, in this paper, is considered in one-row heat exchanger, that fins are hotter than air flow and water is added to fins. related governing equations are derived by analyzing a two-dimension model in a unique cell of a heat exchange. these equations are numerically solved by finite difference method. heat transfer and efficiency under partially wet surface are calculated by...

In this paper, Wavelet Collocation Method has been used to solve nonlinear fin problem with temperature dependent thermal conductivity and heat transfer coefficient. Thermal conductivity of fin materials varies any type so that we consider thermal conductivity as the general function of temperature.  Here we consider three particular cases, where we assume that thermal conductivity is constant,...

in this research the simulation of an air independent proton exchange membrane fuel cell (pemfc) propulsion system was taken into consideration. the system consists of several parts including pem fuel cell stack, metal hydride and liquid oxygen (lox) tanks, and also pre-heaters of oxygen and hydrogen gases along with other heat exchangers, to ensure proper operation of system. the heat recovery...

The KB-5 high pressure gas burners were popularly and widely used in Thailand. This research was aimed to study the influence of four significant parameters, namely degrees of outer and inner ports and the number of outer and inner ports of high pressure gas burners, to the thermal efficiency by the experiments. The thermal efficiency was tested with reference to the standard industrial stoves ...

In the real solar tower thermal power system, it is widely acknowledged that the thermodynamic irreversibility, such as convective and radiative loss on tower receiver, and thermal resistance in heat exchangers, is unavoidable. With above factors in mind, this paper presents an ideal model of the solar tower thermal power system to analyze the influence of various parameters on thermal and exer...

in this paper, the heat balance of an engine was investigated experimentally. the experimental work was conducted on the ef7 natural gas fueled and turbocharged engine. the main goal was to develop an empirical equation to be able to predict the heat balance of the engine at various loads and conditions. the data were collected at four different conditions, two different loads and two different...