The wind test on heat loss from three coil cavity receiver for a parabolic dish collector

The heat loss from cavity receiver in parabolic dish system determines the efficiency and cost effectiveness of the system. A modified three coil solar cavity receiver of inner wall area approximately three times of single coil receiver, is experimentally investigated to study the effect of fluid inlet temperature (Tfi=50 degrees C to 75 degrees C) and cavity inclination angle (theta = 0 degrees to 90 degrees) on the heat loss from receiver under wind condition for head on wind and side on wind velocity at 3 m/s. Overall it was found that the natural and forced convection total heat loss increases with increase in mean fluid temperature. The combined heat loss decreases sharply with the increase in cavity inclination and observed to be maximum for horizontal position of receiver and minimum with the receiver facing vertically downward for all investigations. The maximum heat loss in wind test (V=3m/s) is 1045 W at theta=0 degrees cavity inclination at mean fluid temperature 68 degrees C and minimum at 173 W theta=90 degrees at 53 degrees C. Total heat loss from the receiver under wind condition (V=3m/s) is up to 25% higher (1.25 times at 0 degrees inclination) than without wind at mean fluid temperature similar to 70 degrees C and minimum 19.64 % (1.2 times at 90 degrees inclination) in mean temperature similar to 50 degrees C. In horizontal position of the receiver (theta=0 degrees), the total heat loss by head on wind is about 1.23 times (18% higher ) as compared to side on wind (at fluid mean temperature similar to 70 degrees C). For receiver facing downward (theta=90 degrees), for head-on wind, total heat loss is approximately the same as that for side-on wind

Construction and demolition waste as a road construction material for flexible pavements

This research is focuses on evaluating the physical properties and durability characteristics of both demolition and process waste for flexible pavement construction. The initial results showed that there is a possibility to replace aggregate base course using crushed concrete material of demolition waste Possibility to replace soil using construction and demolition waste as a stabilization agent are to be studied. This study included extensive laboratory and field testing. California bearing ratio (CBR), moisture susceptibility and abrasion evaluations tests are conducted. Effects of repeated load over the constructed pavement are evaluated using Nondestructive testing (falling weight deflectometer) on accelerated pavement testing facility

Numerical investigation of semiempirical relations representing the local Nusselt number magnitude of a pin fin heat sink

Heat transfer augmentation study using air jet impingement has recently attained great interest toward electronic packaging systems and material processing industries. The present study aims at developing a nondimensional semiempirical relation, which represents the cooling rate (Nu) in terms of different geometric and impinging parameters. The spacing of the fin (S/dp) and the fin heights (H/dp) are the geometric parameters, while the impinging Reynolds number (Re) and nozzle‐target spacing (Z/d) are the impinging parameters. During the plot of the Nusselt profile, three vital secondary peaks are observed due to local turbulence of air over the heat sink. To incorporate this nonlinear behavior of the Nusselt profile in developing nondimensional empirical relations, the Nusselt profiles are divided into different regions of secondary rise and fall. Four different sets of the semiempirical relation using regression analysis are proposed for Z/d ≤ 6, H/dp ≤ 4.8 with S/dp ≤ 1.58, S/dp > 1.58 and for Z/d > 6, H/dp > 4.8 with S/dp ≤ 1.58, S/dp > 1.58. These empirical relations benefit the evaluation of the cooling rate (Nu) without any experimentation or simulation

A Posteriori Multiobjective Self-Adaptive Multipopulation Jaya Algorithm for Optimization of Thermal Devices and Cycles

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Validation of the Coupled Heat and Moisture in the Soil for Underground Thermal Energy Storage Systems

The Renewable Energy System for Residential Building Heating and Electricity Production (RESHeat ) system is a typical application of the utilisation of sun-tracked Photovoltaic Thermal (PVT) panels and underground heat storage units. This work introduces a MATLAB simulation model coupled with moisture and heat transfer processes. Validation of the proposed model from experimental measurements was conducted. The simulations were performed for a single year of RESHeat system operation for demo sites located in Cracow City. Results showed that the relative error between calculation and measurement varies from 0.258 % to 5.829 %, along with the same temperature trend. A Control Volume method is used to simulate coupled heat transfer in the ground

A comparative analysis between sampling patterns for airborne PM10 mapping in the extractive sector

Designing a sampling strategy for any environmental variable with the aim of defining a contour map from field surveys entails making decisions about sampling pattern and number of samples. This paper is aimed to assess the influence of sampling strategies on the spatial estimation of PM10 concentration in a quarry environment. An intensive field survey consisting in more than two hundred samples was planned to fully investigate the spatial variability of the selected area. Then systematic, random and stratified random sampling schemes were compared by means of several iterative subsamplings of the well known data set deriving from monitoring campaigns. Different grid resolutions were selected and their correspondent variograms plotted. The corresponding structural analysis, when compared with output from raw data, allowed to point out the best sampling approach for this phenomeno

Optimization of a thermal storage tank for a water-water heat pump solar assisted

Thermal energy storage plays a key role in renewable resource management by finding a balance between random renewable energy production and building energy demand. This work investigates the role of thermal energy storage in a system consisting of a water source heat pump, and hybrid photovoltaic thermal panels (PVT), connected by the thermal storage tank for heating a residential building. Using a mathematical model built in Simulink, the fraction of thermal energy produced by the PVT and stored in the buffer tank and the fraction related to the coverage of the load by the renewable resource was evaluated as a function of the volume of the buffer tank and of the set-temperature point to the cold sink of the heat pump. The results show that for each degree less required at the cold source of HP there is an average annual increase of the before-mentioned fractions of 6.0%. By quadrupling the volume of thermal storage, the fraction of thermal energy accumulated increases by 73%, and the fraction of load coverage by renewable energy increases by 30%