Analytical and Experimental Investigation of a Triangular-Channeled Solar Water Heater

Utilization of solar energy is increasing in different states of the world, and the sun is regarded as the largest source of continuous and coherent energy. In the present study, a novel configuration of a v-corrugated solar collector with triangular channels for domestic water heating has been analytically investigated. A mathematical model based on effectiveness-NTU method is established to thermally examine the collector. Additionally, the heat losses from the body of the collector, useful energy from the collector and solar efficiency have been calculated analytically over different operating parameters. The effects of mass flow rate and solar heat flux on water outlet temperature are evaluated analytically and compared with the experimental results. Moreover, the study includes the experimental and theoretical investigation of the heat exchange effectiveness and thermal efficiency of the proposed absorber. The study shows that high temperature and high performance can be obtained from this collector as more heat energy can be collected by using triangular channels because all the three sides of these channels are exposed to solar radiations at the same time. Therefore, these channels will enhance the collector exposed surface area and thereby increase the solar efficiency and overall performance of the system.

Heat Exchange Effectiveness and Pressure Drop for Air Flow Through Perforated Plates With and Without Crosswind

Low-porosity perforated plates are being used as absorbers for heating ambient air in a new type of unglazed solar collector. This paper investigates the convective heat transfer effectiveness for low-speed air flow through thin, isothermal perforated plates with and without a crosswind on the upstream face. The objective of this work is to provide information that will allow designers to optimize hole size and spacing. In order to obtain performance data, a wind tunnel and small lamp array were designed and built. Experimental data were taken for a range of plate porosities from 0.1 to 5 percent, hole Reynolds numbers from 100 to 2000, and wind speeds from 0 to 4 m/s. Correlations were developed for heat exchange effectiveness and also for pressure drop. Infrared thermography was used to visualize the heat transfer taking place at the surface.

Parametric Analysis of Horizontal Air and Liquid Earth Loops

Equations and parameter characteristics were examined for both closed and open-earth loops. Analysis and graphs are presented on the heat exchange effectiveness of air and liquid earth loops and how the heat transfer is affected by major parameters such as: pipe diameter, soil thermal conductivity, fluid velocity, and fluid type. The open loop will produce more heat per unit length of pipe while the closed produces more total system heat. However, final loop selection is based on many factors that are both site and system specific.