In this paper, performance analysis of a hybrid photovoltaic-thermal (PV/T) greenhouse air heater and dryer has been carried out. Analytical expressions have been developed for • greenhouse air temperature, instantaneous and overall energy and exergy efficiencies for without load and • instantaneous exergy efficiency with load under forced mode operation. An experimental validation has been car...

In this paper exergy analysis is used to assess the performance of the three most common air conditioning plant schemes: all-air, dual-duct and fan-coil systems. The results are presented in terms of flow diagrams to provide a clear picture of the exergy flow across the systems. The most relevant outcomes are that the air cooling and dehumidification is the process most responsible for the exer...

Since the eco-efficiencies of all industrial processes/plants have become more and more important, engineers need to find a way to integrate control loop configuration and measurements of eco-efficiency. A new measure of ecoefficiency for control loop configuration was developed, the exergy efficiency factor. The exergy efficiency factor is based on the thermodynamic concept of exergy which can...

This paper applies an exergy-based method on the two-dimensional airfoil and various threedimensional wing planforms to investigate the impact of exergy on aerodynamic designs. Our intent here is to report our efforts to couple a numerical code with an exergy analysis, a shape shifting algorithm and an optimization code to achieve desired airfoil and wing shapes. Exergy-based optimization is pe...

Absorption chillers present opportunities to utilize sustainable fuels in the production of chilled water. An assessment of the steam driven absorption chiller at the University of Idaho, was performed to quantify the current exergy destruction rates. Measurements of external processes and flows were used to create a mathematical model. Using engineering equation solver to analyze and identify ...

Exergy analysis is a powerful diagnostic tool in thermal systems performance evaluation. The use of such an analysis in seawater desalination processes is of growing importance to determine the sites of the highest irreversible losses. In the literature, exergy analyses of seawater desalination systems have sometimes modeled seawater as sodium chloride solutions of equivalent salt content or sa...

Organic Flash Cycle (OFC) has potential of improving efficiency for recovery of low temperature heat sources mainly due to reducing temperature mismatch in the heat exchanger. In this work exergetical performance analysis of ORC is conducted for recovery of low grade heat source. Effects of system parameters such as flash evaporation temperature or heating temperature are theoretically investig...

Exergy is a concept that is gaining an increasingly wider recognition as a proper measure for the actual energy resources consumed, when energy is used. Energy as such is indestructible, but exergy is not. As entropy is generated while energy is used, exergy is consumed. Exergy can be interpreted as the qualitative content of energy, or as energy in its highest quality. Therefore, there is an i...

In this work, we present the application of exergy analysis in the evaluation of the ethanol steam reforming (ESR) process in a catalytic membrane reactor (CMR) containing Pd-Ag membranes sandwiched by PdRh/CeO2 catalyst to produce fuel cell grade pure hydrogen (no sweep gas). ESR experiments were performed at T=873-923 K and P=4-12 bar. The fuel was a mixture of ethanol and distilled water wit...

The present paper describes the energy and exergy analysis of a reheat regenerative vapor power cycle. The plant consists of one boiler feed pump, one supercritical boiler, two steam turbines with a reheater in between, two feed water heaters (one open and one closed) and a condenser. The energy and exergy balance study has been carried-out for each component of the plant. Energy efficiency, ex...