Depletion of freshwater resources and reduced rainfall in arid regions lead to water scarcity, which is exacerbated by population and urbanization growth. This study proposes a small-scale Solar thermal/seawater desalination combisystem using a nano fluid-based direct absorption Solar collector and a humidi, cation and dehumidi, cation desalination unit to meet the domestic hot water, space heating, and fresh water needs of a residential building. The dynamic simulation of the system performance in the hot-dry climate zone is done using the TRNSYS-MATLAB co-simulator. The results show that the use of the proposed combisystem reduces the annual energy consumption by 94. 3% and 17%, respectively, for the provision of domestic hot water and space heating requirements. The supply of freshwater demand ranges from 11. 3% to 100%. In addition, freshwater production decreased by an average of 18%. In the case of at-panel Solar collectors, the fraction of Solar energy used for domestic hot water and space heating needs was reduced by 3. 7% and 1. 7%, respectively, compared with nano fluid-based direct absorption Solar collectors. The payback period using nano fluid-based direct absorption and at plate Solar collectors are 6. 4 and 7. 8 years, respectively.

In the world today, fossil fuels as conventional energy sources have a crucial role in energy supply since they are substantial drivers of the “ Industrial Revolution” , as well as the technical, social, and economic developments. Global population growth along with high levels of prosperity have resulted in a significant increase in fossil fuels consumption. However, fossil fuels have destructive impacts on the environment, being the major source of the local air pollution and emitter of greenhouse gases (GHGs). To address this issue, using renewable energy sources especially Solar energy as an abundant and clean source of energy, has been attracted considerable global attention, which can provide a large portion of electricity demand. To make the most of Solar energy, concentrated Solar power (CSP) systems integrated with cost effective thermal energy storage (TES) systems are among the best options. A TES system has the ability to store the thermal energy during sunshine hours and release it during the periods with weak or no Solar radiation. Thus, it can increase the working hours as well as the reliability of a Solar system. In this paper, the main components of the Solar thermal power systems including Solar collectors, concentrators, TES systems and different types of heat transfer fluids (HTFs) used in Solar farms have been discussed.

The efficiency of a household thermostat Solar water heater model with two flat panel collectors and a double-glazed storage tank of 200 liters capacity was investigated experimentally. Water and glycol (antifreeze) are used as operating fluid in the water heater to be transformed into thermosyphon with free movement and increase the temperature of consumed water. Water is not discharged during the test period. Flow temperatures of collector input and output, city water temperature, water temperatures at different points in the reservoir and ambient temperature for sunny days in the autumn in Tehran. Measurement and flow rate of the thermosyphon, thermal energy of the water consumed and total water efficiency The aforementioned heater has been calculated and the corresponding graphs are given over time. The results show that the highest water temperature is 60 °C on sunny days and 50 °C on cloudy days. The overall efficiency of the thermostat Solar thermal heater will be around 45درصد during the month of November 1396. The highest photovoltaic panel efficiency in the sunny days is 13.5% in the autumn and 11.6% in the cloudy days, which is due to the decrease in efficiency compared to the ideal conditions. The surface temperature of the panel is high.

Unglazed transpired Solar collectors (UTCs) are Solar air heating collectors that used for preheating air in ventilation systems or producing hot air for drying systems. thermal performance of UTCs is a function of various parameters including incident Solar radiation, air approach velocity, diameter and pitch of perforations. Modeling predicts the thermal performance of UTCs over a wide range of design and operating conditions. This paper presents the details of modeling for UTC using heat transfer expressions for the collector components and energy balances. The effects of key parameters on the performance of a UTC were studied by varying the approach velocity, Solar radiation, diameter and pitch of perforations and finding their influence on collector thermal efficiency, heat exchange effectiveness and outlet air temperature. Results showed that the UTC thermal efficiency increases by increase in Solar radiation and approach velocity, but the efficiency decreases by increasing plate hole diameters and pitch.

This study analyzes the thermal performance of Solar thermal energy using double-pass absorber plate in Sanandaj, Iran. To this end, a mathematical model was encoded according to the energy and exergy balance equations and solved by MATLAB software. Given the environmental conditions and radiation intensity of a winter day in Sanandaj, the effects of external parameters such as radiation intensity and internal parameters like canal’ s height, inlet mass flow rate, absorber length as well as some physical parameters on the efficiency of the system were analyzed and the energy and exergy output of the system was studied. To validate the proposed model, the results obtained from numerical simulation were compared with experimental data, which showed an acceptable compatibility. Finally, the ability of the system to supply the thermal load of the building in the given day was examined and the roles of various factors in the area under thermal coverage of this system were analyzed. The obtained findings indicated that a system with an area of 3 m2 and mass rate of 250 kg/h in radiation intensity of 619 W/m 2 and temperature of 3. 45° is capable of supplying the thermal load of a space with an approximate area of 14 m.

prevention from thermal losses in buildings and using environmental potentials such as Solar energy, are two fundamental strategies in designing buildings with the approach of saving nonrenewable energy resources. As a border between the interior space and the environment, the building envelope plays a determining role in approaching these strategies. It is expected from the building’ s envelope to mitigate unwanted energy dissipations and protect occupants from severe weather conditions. At the same time, a well-designed building envelope should provide the occupants’ comfort using environmental potentials, and ideally it may even take part in fulfilling energy demands. The importance of energy harvesting in building envelops is more recognized in metropolises in which the growth of high-rise construction causes an intense decrease in the ratio of sun exposed horizontal surfaces such as roofs or yards to the area of floors. However, on the height of building and the overall area of floors-and followed by them, demand for energy-increases, the area of vertical surfaces such as facades, increases in a more appropriate proportion. Additionally, installing Solar energy equipment on horizontal surfaces with high potential of functionality, is usually an undesirable interference in architecture. From another point of view, conventional insulating stops the wall from transferring Solar energy to the interior spaces. This research aims to make a convergence between high thermal resistance and Solar energy collection. To achieve this, different methods of Solar energy collection was reviewed. Due to the large angles between the sun’ s altitude and the normal vector of southern faç ades, especially in summer days, a significant part of Solar radiation is reflected from the cover glass surface of flat collectors. Non-glazed collectors, because of large amount of heat loss, have a low efficiency and like the conventional flat collectors, do not transfer the light and ban the transparency. However tubular evacuated Solar collectors, if installed horizontally on southern faç ade, represent a circular section which is always perpendicular to the rays of sun, regardless of the altitude of radiation. So, Solar reflection from glass cover of the collector, will no longer depend on the sun’ s vertical position in the sky in different seasons. Also, the relative vacuum-made possible according to tubular form-decreases heat loss to a minimum. According to these two facts, this type results in an appropriate performance, which enables the envelope to provide a part of heating load and indirectly, cooling loads by supplying an absorption/adsorption chiller or a desiccant cooling machine. The concept of the proposed system is a combination between the idea of tubular evacuated Solar collector and vacuum transparent insulation. It consists of aluminum blades covered with a selectively Solar absorbing coating, arrayed like a louver, surrounded by an evacuated glass container with corrugated skin. The result is a modular faç ade panel, with a high thermal resistance, which efficiently takes part in Solar energy collecting and at the same time, acts as a louver to protect the interior spaces from direct Solar radiation, while providing a relative visual transparency and daylight transmission.

The experimentation is carried out to examine the influence of receiver aperture/opening ratio (receiver’ s aperture diameter to the maximum diameter ratio, d/D), glass cover thickness and inclination angle of cavity receiver on its collection efficiency for various flow rates of ordinary water as a working fluid. Experimental tests have been conducted at lower incident energy, i. e., at lower cavity wall temperatures (less than 200 ° C). The aperture ratio examined encompasses values as 0. 46, 0. 6, 0. 7, and 0. 93 for water flowing at flows of 0. 8, 0. 65, 0. 5, and 0. 4 LPM that corresponds to Reynolds numbers (Re) of 1880, 1525, 1175, and 938, respectively. The glazing thicknesses of 6, 4, and 2 mm were provided at an aperture. A modified cavity-type receiver is made inclined at angles 90° , 60° , 45° , and 30° (with 90° as down-facing receiver opening and 30° as close to sideway-facing of receiver opening). The tests have been conducted for cavity surface temperatures ranging from 90° to 180 ° C. It is observed that an aperture ratio of 0. 6 demonstrates maximum receiver performance for the values of Reynolds number studied, while the receiver performance exhibited reducing trend with reduction in receiver tilting angle from 90° to 30° .