Most of the energy consumption in a hot and dry area is used for the air-conditioning systems. This study aims to investigate the possibility of reducing the electricity consumption in air conditioners using ground cold energy to cool the hot fluid in the pipes.Several experiments were carried out to investigate the performance of the proposed system to be used in the weather conditions of Baghdad city (i.e., hot and dry).Two configurations of ground source heat exchangers (GSHEs) were developed and constructed. The first configuration comprised coil type with two different materials (copper and polyvinyl chloride [PVC]). The second configuration was the 3U type, which was made from copper, PVC, and galvanized. Three water flow rates were considered (5, 10, and 15 L/min) with water inlet temperatures (80°C, 70°C, and 60°C). The experiments' results showed that the type of material of the pipe has a significant influence on both the heat transfer effectiveness and the system performance.Copper tubes were the best type of heat exchanger (type coil) to be used in this regard. The highest recorded values of the heat exchange rate were 5.81, 4.81, 2.72, 1.60, and 1.32 kW with an inlet temperature of 80°C and a flow rate of 5 L/min for the case of

A combined system with photovoltaic panel modules, which extracts heat from water or air and produces thermal and electrical energy which is called a solar photovoltaic or solar thermal photovoltaic thermal (PV/T) system. A way to enhance the electrical efficiency of the PV module is by diminishing the temperature at which the module is working, i.e. by extracting thermal energy. The design of the solar Photovoltaic/Thermal provides certain advantages. When the temperature is increased 1°C, the photoelectric efficiency decrease by 0.5%. This work is principally aimed to clarify the effectiveness by means of the exergy generated in a PV/T hybrid water module, a photovoltaic thermal module, generating thermal and electrical energy. Were determined the energy, exergy and the efficiency of the power conversion for a certain amount of days in function of the solar intensity, the temperature of the module and environmental temperature. During the hours 9:00 am to 3:00 pm, the efficiencies of exergy and power conversion varies according to the following values, between 2.16 - 12.27% for the exergy efficiency and between 5.2 - 11.2% for the power conversion efficiency as well as, the energy efficiency varies between 6.89 – 14.9%. The temperature of the photovoltaic module has a great impact on the electrical, thermal and exergy efficiencies. Moreover, these efficiencies can be enhanced by removing energy in form of heat from the surface of the photovoltaic module.

In this work, experimental and numerical analyses have been executed to investigate the effect of using cooling techniques on the performance of the photovoltaic thermal solar panel (PV/T). It is well known that a decrease in the panel temperature will lead to an increase in the electrical efficiency. The photovoltaic/thermal (PV/T) collector is a combination of PV cells and a solar thermal collector in one unit, which can together generate electrical and thermal energy. In the theoretical study, the electrical characteristics of PV were analyzed by using (MATLAB PROGRAM). The panels were oriented south and tilted at 45o. All tests are carried out in Baghdad city at (May, June and July) in 2018; under clear sky conditions. The experimental study includes four cases (modules). Module I contains open cell aluminum metal located in water passages box of a 9-liter capacity in the back of PV panel. Module II contains only water pass. Module III comprises copper slices that are located in the water box. The first three cases are compared with the conventional PV panel under the same conditions. compares between the PV with open cell aluminum metal and the other PV with copper slices. The results manifested that the cooling of PV panel in the module III is better than the others, but economically, the use of module I is the best, therefor it is found a more acceptable technique for hot climate conditions

Heat transfer around a flat plate fin integrated with piezoelectric actuator used as oscillated fin in laminar flow has been studied experimentally utilizing thermal image camera. This study is performedfor fixed and oscillated single and triple fins. Different substrate-fin models have been tested, using fins of (35mm and 50mm) height, two sets of triple fins of (3mm and 6mm) spacing and three frequenciesapplied to piezoelectric actuator (5, 30 and 50HZ). All tests are carried out for (0.5 m/s and 3m/s) in subsonic open type wind tunnel to evaluate temperature distribution, local and average Nusselt number (Nu) along the fin. It is observed, that the heat transfer enhancement with oscillation is significant compared to without oscillation for low air inlet velocity. Higher thermal performance of triple fins is obtained compared to the single rectangular fin, also triple fins with (height=50mm and finspacing=3mm) gives better enhancement as compared to other cases. This work shows that the piezoelectric actuator when mounted on the rectangular fins shows great promise for enhancing the heat transfer rate.

The present work describes numerical and experimental investigation of the heat transfer characteristics in a plate-fin, having built-in piezoelectric actuator mounted on the base plate (substrate). The geometrical configuration considered in the present work is representative of a single element of the plate-fin and triple fins. Air is taken as the working fluid. A performance data for a single rectangular fin and triple fins are provided for different frequency levels (5, 30 and50HZ) , different input power (5,10,20,30,40 and 50W) and different inlet velocity (0.5, 1, 2, 3, 4, 5 and 6m/s) for the single rectangular fin and triple fins with and without oscillation. The investigation was also performed with different geometrical fin heights ( 50mm and 35mm) and distance between the fins (3mm and 6mm). It is observed that the heat transfer increases with the increase in the frequency and Reynolds number. It is further observed that triple fins with (height=50mm and distance between the fins=3mm) gives better enhancement as compared to othercases, The study shows that the piezoelectric actuator when mounted on the rectangular fins gives great promise for enhancing the heat transfer rate