Exercise I. Optimization of a heater. We want to optimize the temperature T of a room Ω by the mean of a heater ! whose heat flux v ∈ L(!) is controlled. An air stream of velocity u fills the room. We assume that the air is incompressible, that is u is assumed to be divergence free. Moreover, u is also assumed to be regular. The temperature on the boundary of the room is equal to the external t...

The problem of solar radiation intermittency can significantly affect the thermal performance air heaters (SAHs). efficient solution for this is utilizing storage to store energy and using it again in off sunshine hours. present study analyzed two configurations counterflow double pass heater. first configuration included a conventional flat plate absorber, while second involved tubular capsule...

drying of agricultural products is a sophisticated process with high energy consumption. energy needed for sustainable development, is one of the biggest challenges facing humanity. the performance of a heat recovery assisted solar dryer was evaluated in this study. drying time, collector efficiency, energy consumption, solar fraction and energy recovery fraction were investigated at different ...

The implementation of variable artificial roughness patterns on a surface is an effective technique to enhance the rate of heat transfer to fluid flow in the ducts of solar air heaters. Different geometries of roughness elements investigated have demonstrated the pivotal role that vortices and associated turbulence have on the heat transfer characteristics of solar air heater ducts by increasin...

Transparent, conductive, and flexible Ag nanowire (NW)-polyimide (PI) composite films were fabricated by a facile solution method. Well-dispersed Ag NWs result in percolation networks on the PI supporting layer. A series of films with transmittance values of 53-80% and sheet resistances of 2.8-16.5 Ω/sq were investigated. To further verify the practicability of the Ag NWs-PI film in optoelectro...

Solar-heated air can be used in a wide variety of applications, but it is a limited resource. Only so much sunshine strikes each square foot of the earth, and a well-built collector system will typically deliver about half of this energy to a house in the form of heat. The way this heat is used often means the difference between a useful, cost-effective system and one that never seems to perfor...

Abstract The performance stability of the system can be improved by incorporating a solar chimney with phase-change material (PCM). It is recommended that instead using traditional multi-curved trough air collectors for greenhouses, phase change thermal storage wall construction vertical channels employed. Solar utilization rear wall. In order to verify feasibility system, collector test greenh...

Solar heating is one of the important utilities of solar energy both in domestic and industrial sectors. Evacuated tube heaters are a commonly used technology for domestic water heating. However, increasing cost of copper and nickel has resulted in huge initial cost for these types of heaters. Utilizing solar energy more economically for domestic use requires new concept which has low initial a...

Utilizing thermal storage integrated into a solar air heater SAH is promising solution to enhance the performance of heaters. The present work experimentally investigated impact an absorber-finned heat exchanger-thermal unit inside heater. experiments were conducted under conditions Tikrit-Iraq in December 2021 and January 2022. RT42 RT50 used as PCMs two separate Each PCM filled SAH. A finned ...