The sun which is all energy sources, in today's society, hot water is used for various purposes starting from household to power production. People are adopting various ways to accomplish these goals, such as firewood heat and electrical power, so solar energy is an alternative to the dwindling resources of fossil fuels. Conversion of solar radiation into heat is one of the simplest and most direct applications of this energy, it can be used to heat water systems. A widely used flat-plate solar collector. In this study we have come to heat water using solar energy. This research presents the design and experimental analysis for using Spiral Flow Solar Water Heater (SFSWH) to enhance the thermal efficiency of a flat plate solar collector. Where a solar water heater consists of a copper tube in the shape of a spiral is fixed on an iron flat plate as an absorber. The experiment also includes the selection quality of the paint used to dye the absorbent surface. In May at Fallujah (33.34ºN, 43.8ºE), the thermal performance was calculated. The maximum temperature difference in the storage tank of about 18 ℃ for (SFSWH) during the experimental time was obtained. The efficiency of the collector was obtained is about (80.11%). Where it gives an increase (40 %) in its efficiency compared to published values.

This paper describes a numerical method for calculating the temperature distribution and latent heat storage (LHS) in the treated wall (TW) and non-treated wall (NTW). The developed method was assumed that the outer cement layer (Iraqi wall) enveloping the external wall of building and houses are contains paraffin wax as a phase change material (PCM). ( 25%) is the volume percentage of paraffin wax is mixed with cement which forming a treated layer. A comparison results between the (TW) and (NTW) has been done. The paper presents a simple calculation of case study for air-conditioning in two walls type of residential building. The outer solar air temperatures as function of day time are considered for a hot day in summer (July) for Baghdad city. The aim of this paper was to obtain physical validation of the numerical results produced from using developed FORTRAN program. This validation was obtained through a comparison of numerical solution of two different wall compositions exposed to the same external and internal load conditions. The calculations on transient heat transmissions across different walls were conducted. It was found that when using the (TW) with (PCM) produces lower surface and heat flux towards the cooling space with respect to (NTW).

This paper describes the developed method for predictions of transient internal surface temperatures and heat-flux obtained from thermocouples, which are installed through the wall of the rocket motor nozzle. Heat-Flux was estimated by using the prediction of internal surface temperatures from numerical solutions of the inverse heat conduction problem (IHCP). Three Heat-Flux gauges are manufactured and used in convergent, throat, and divergent sections. The temperatures are measured with starting operation of the rocket motor along the gauges where the thermocouples are connected to the data acquisition system interfacing with the PC. The measured unsteady temperature behavior is approximated by polynomials third degree in space and time. The measurement results indicate that the maximum reading temperatures are at the throat section. No differences in time were appearing in curves to reach maximum prediction surface temperatures.

Two-dimensional numerical simulation is performed aiming to understand the role of buoyancy force convection during restricted solidification of phase change materials (PCMs) inside a shell and tube heat exchanger according to annulus cross section. Where the transient history of PCM solidification evolution was studied. The governing equations of mass, momentum and energy are solved to study the solidification behavior inside the annulus geometry. The fluid flow in the mushy zone was accounted for using the Darcy drag source term in momentum, and the liquid percentage in each cell was updated using the enthalpy-porosity method. Thermal conditions of the outer cylinder insulated (adiabatic) and the inner cylinder at constant temperature (isothermal). The results are presents as a temperature contour and liquid fraction distribution in the domain. The predicted result shows the capturing phenomenon: primary heat conduction in all regions, then heat convection and conduction become dominant in the top and bottom regions, respectively. The max. and min. temperature changes near the outer pipe surface during 16 hrs. are 56.25% and 42.5%, respectively.