Solar Cooling Technologies

This chapter describes different available technologies to provide the cooling effect by utilizing solar energy for both thermal and photovoltaic ways. Moreover, this chapter highlights the following points: (i) the main attributes for different solar cooling technologies to recognize the main advantages, challenges, disadvantages, and feasibility analysis; (ii) the need for further research to reduce solar cooling chiller manufacture costs and improve its performance; (iii) it provides useful information for decision-makers to select the proper solar cooling technology for specific application. Furthermore, some references, which include investigation results, will be included. A conclusion about the main gained investigation results will summarize the investigation results and the perspectives of such technologies

Energy analysis and modeling study of combined activated carbon-silica gel/methanol adsorption ice production system

In this article, the transient modelling for a new construction of the Adsorption cold production was investigated. This system, named in this work the combined Adsorption Ice Production system (com-AIP system), was filled by both silica gel (SG) and activated carbon (AC) together in one adsorption reactor as the adsorbent and methanol as the adsorbate and refrigerant. A fined-tube heat exchanger was designed (named combined adsorption reactor) in order to contain two different adsorbents in the adsorption reactor and increase the heat transfer ability between the particles of adsorbents and heat exchanger fins. As a result the input energy required from the external heat source is saved and the coefficient of performance COP of the com-AIP system is improved. The mass flow rate of refrigerant increases and consequently, the refrigeration energy Qe rises too. A cycle simulation computer program of this innovative bed was developed to analyze the refrigeration energy and COP variations by varying heat transfer fluid (hot, cooling and chilled water) inlet temperatures and adsorption/desorption cycle time. The transient behavior of heat and mass transfer fluids has been also studied. Under the standard test conditions of 100 °C hot water, 24 °C cooling water, and 15 °C chilled water inlet temperatures, the simulation results showed that the amount of the ice produced per cycle of 5.34 kg and 0.73 COP can be achieved from the com-AIP system. It was found that the system performance is very much sensitive to the mass flow rate of the refrigerant. The cycle time of the system is not dependent on the amount of the adsorbents but is strongly dependent on driven temperature of heat exchange fluid and the design of the heat exchanger. The com- adsorption reactor allows using the advantages of physical properties of both adsorbents SG and AC. Consequently, this innovative com-AIP system utilizes effectively low-temperature heat sources of temperature between 65 and 100 °C, because of the inferior thermodynamic properties of methanol and the low regeneration temperature from silica gel and activated carbon as adsorbents. This strategy (com-AIP system) is completely different from the conventional adsorption reactors, which are filled with one adsorbent in one bed or in two beds

Enhancing the amount of cold produced and saving of the required input heat using two different adsorbents together in the adsorption ice production AIP system

A theoretical investigation of the thermal performance (coefficient of performance COP and specific cooling power SCP) of a two bed Adsorption Ice Production AIP system based on the Silica gel-methanol as adsorbent- refrigerant in the first bed and activated carbon-methanol in the second bed is presented in this paper. Two fined-tube heat exchangers were designed (named SG-bed and AC-bed) in order to generate the same desorbed refrigerant amount of 1 kgmeth and to contain two different adsorbents. The mass transfer limitations from both the two beds and the heat transfer ability between the particles of adsorbents and heat exchanger fins are taken into account in the simulated model based on the linear driving force LDF model. To desorb 1 kgmeth from the SG-bed and AC-bed a cycle simulation computer program of the AIP system was developed to investigate the effect of desorption temperature Tdes, adsorption temperature Tads and the effect of difference of the required desorption/adsorption time on the system performance and on the amount of the ice produced per cycle mice. In the present simulations, the variation of the heat source temperature from 65 to 100 oC and chilled water temperature from 15 oC to 25 oC are taken. The results showed, that the AIP system attains a coefficient of performance COP of 66 % when the AC-bed is working and attains of 44 % when the SG-bed is working. The amount of the ice produced from the system estimated to 6kg per cycle (3 kg is produced from each of bed), but the Qin input energy required to activate the AC-bed has been saved by 46 % compared with that required to activate the SG-bed. Although each of the adsorbent beds was filled with different amount of the sorption material, it is found that the mass of the sorption materials inside the both beds has no effect on the cycle time but has important effect on the specific cooling power SCP. The cycle time is strongly dependent on driven temperature of heat exchange fluid, the design of the heat exchanger and the mass transfer coefficient of sorption material Dso. An experimental set up is planned to be built to make validation of the simulation results

Energy Analysis and Modeling Study of Combined Activated Carbon-Silica Gel/Methanol Adsorption Ice Production System

In this article, the transient modelling for a new construction of the Adsorption cold production was investigated. This system, named in this work the combined Adsorption Ice Production system (com-AIP system), was filled by both silica gel (SG) and activated carbon (AC) together in one adsorption reactor as the adsorbent and methanol as the adsorbate and refrigerant. A fined-tube heat exchanger was designed (named combined adsorption reactor) in order to contain two different adsorbents in the adsorption reactor and increase the heat transfer ability between the particles of adsorbents and heat exchanger fins. As a result the input energy required from the external heat source is saved and the coefficient of performance COP of the com-AIP system is improved. The mass flow rate of refrigerant increases and consequently, the refrigeration energy Qe rises too. A cycle simulation computer program of this innovative bed was developed to analyze the refrigeration energy and COP variations by varying heat transfer fluid (hot, cooling and chilled water) inlet temperatures and adsorption/desorption cycle time. The transient behavior of heat and mass transfer fluids has been also studied. Under the standard test conditions of 100 °C hot water, 24 °C cooling water, and 15 °C chilled water inlet temperatures, the simulation results showed that the amount of the ice produced per cycle of 5.34 kg and 0.73 COP can be achieved from the com-AIP system. It was found that the system performance is very much sensitive to the mass flow rate of the refrigerant. The cycle time of the system is not dependent on the amount of the adsorbents but is strongly dependent on driven temperature of heat exchange fluid and the design of the heat exchanger. The com- adsorption reactor allows using the advantages of physical properties of both adsorbents SG and AC. Consequently, this innovative com-AIP system utilizes effectively low-temperature heat sources of temperature between 65 and 100 °C, because of the inferior thermodynamic properties of methanol and the low regeneration temperature from silica gel and activated carbon as adsorbents. This strategy (com-AIP system) is completely different from the conventional adsorption reactors, which are filled with one adsorbent in one bed or in two beds

Analytical and Comparative Study of a Mini Solar-Powered Cogeneration Unit Based on Organic Rankine cycle for Low- Temperature Applications

In this paper, we analyze characteristics of a small Combined Heat and Power (CHP) system based mainly on Organic Rankine Cycle (ORC) and heating plant in actual series connection regarding the low-temperature heat carrier heated by purely solar flat collector field. Simultaneously and for specific power production, comparison of this layout with stand-alone ORC, and with the traditional ORC-CHP imposing gain of condenser heat for heating aims, in second step, has been conducted. For evaluation, energetic and design criteria have been determined opposite the heating effects and also temperatures of the heat source and sink. The simulations addressed interesting optimization ratios till 24 % for the power unit throughout this series CHP utility versus single power generation at the same conditions tested. Moreover, the high heat source temperatures and CHP ratios improve the performance of the overall series plant, while the high supply and return temperatures have negative effects. Finally, the ORC-CHP scheme handled here highlights distinctive exploitation aspects and more suitability in wide range of application in comparison to yielding the high-temperature condensation heat of ORC, especially at low ambient temperatures, high supply and heat source temperatures. So, it can be advised to be adopted instead of the two other strategies

Analytical and Comparative Study of a Mini Solar-Powered Cogeneration Unit Based on Organic Rankine cycle for Low-Temperature Applications

In this paper, we analyze characteristics of a small Combined Heat and Power (CHP) system based mainly on Organic Rankine Cycle (ORC) and heating plant in actual series connection regarding the low-temperature heat carrier heated by purely solar flat collector field. Simultaneously and for specific power production, comparison of this layout with stand-alone ORC, and with the traditional ORC-CHP imposing gain of condenser heat for heating aims, in second step, has been conducted. For evaluation, energetic and design criteria have been determined opposite the heating effects and also temperatures of the heat source and sink. The simulations addressed interesting optimization ratios till 24 % for the power unit throughout this series CHP utility versus single power generation at the same conditions tested. Moreover, the high heat source temperatures and CHP ratios improve the performance of the overall series plant, while the high supply and return temperatures have negative effects. Finally, the ORC-CHP scheme handled here highlights distinctive exploitation aspects and more suitability in wide range of application in comparison to yielding the high-temperature condensation heat of ORC, especially at low ambient temperatures, high supply and heat source temperatures. So, it can be advised to be adopted instead of the two other strategies

A Comparative Investigation on Outdoor and Laboratory Test of the Degradation Rates for Different Types of Photovoltaic Modules with Different Exposure Periods

 Understanding field failure and degradation modes in solar photovoltaic (PV) modules is very important for various reasons especially for this widely used technology. The University of Applied Sciences Ostwestfalen-Lippe in Höxter owns photovoltaic-modules of different cell types, sizes and operation periods in German weather conditions. This paper presents a detailed degradation investigation and performance parameters analysis for chosen samples of polycrystalline, monocrystalline and thin film modules in the laboratory and outdoor test conditions after 10 years of exposure. The obtained measurements were standardized and then compared with the warranted values of the manufacturer’s datasheets for each module type. The real outdoor measurements for the larger units show that the maximum power Pmax after 10 years of exposure for polycrystalline, monocrystalline and amorphous thin film modules had declined by: 8.47%, 37.67%, and 19.05% respectively, which translates to an annual linear degradation rates of 0.652%, 3.67%, and 1.465% for each type respectively. While the maximum power output of the smaller units had declined by 19.05%, 19.36%, and 21.75% for polycrystalline, monocrystalline and amorphous thin film modules respectively, which also translated to annual linear degradation rates of 1.48%, 1.67%, and 0.6% for each type respectively. On the other hand, the laboratory tests for these modules show that there is a clear variation with the obtained outdoor results, where the Pmax for the same larger units had declined by 39.6%, 57.4%, and 82.5% for polycrystalline, monocrystalline and thin film modules respectively, While the Pmax output of smaller units had declined by 51.2%, 39.38%, and 9.39% for polycrystalline, monocrystalline and thin film modules respectively, The comparison of the efficiency and fill factor parameters for the obtained results with the manufacturer’s data shows that the outdoor measurements introduce close results than the laboratory results. The discoloration of the encapsulant is the most frequently occurring visually observable defects on the modules

Investigation Results and Analysis of Solar Cells Performance Enhancement by Cooling using Thermoelectric Cooling (TEC)

 Solar energy received special attention and extensive studies were conducted to increase the efficiency of solar collectors and solar cells. One of the major problems of the operation of solar cells is the temperature rising which causes a reduction in the energy yield. The main objective of this work is to experimentally investigate the cooling effect of thermoelectric cooling devices (TEC) on solar cell performance. To overcome the rising temperature effect, the cooling by using the Peltier device is proposed and investigated. In this approach, the TEC cooling module is attached to the backside of the photovoltaic cell. It is assumed that the required power to run the TEC module is provided by the photovoltaic cell itself when the additional power obtained by the cooling is more than the needed power to operates the TEC device. The results show that the cooling of the tested PV cells/modules samples by using the Peltier TEC device was slightly enhanced the PV cells' performance. In our case of study for a 2Wp solar cell sample, the maximum temperature difference obtained due to Peltier cooling is about 5.3C° which produced an enhancement for the produced power and the open-circuit voltage by 7.02% and 2.64% respectively. However, the needed power to feed the Peltier element is significantly higher than the recovered power due to the Peltier cooling. The same trend was investigated for the tested samples of PV modules. So, the proposed combination of PV and Peltier cooling system was investigated to be economically not feasible regardless of the cost evaluation. Finally, the spatial effect and the proposed system can be improved significantly by altering and improving the performance of the Peltier element and the thermal characteristics of the solar cells/modules encapsulation material

The Effect of Nanomaterial Type on Water Disinfection Using Data Mining

Multiple linear regression and artificial neural network (ANN) models were utilized in this study to assess the type influence of nanomaterials on polluted water disinfection. This was accomplished by estimating E. coli (E.C) and the total coliform (TC) concentrations in contaminated water while nanoparticles were added at various concentrations as input variables, together with water temperature, PH, and turbidity. To achieve this objective, two approaches were implemented: data mining with two types of artificial neural networks (MLP and RBF), and multiple linear regression models (MLR). The simulation was conducted using SPSS software. Data mining was revealed after the estimated findings were checked against the measured data. It was found that MLP was the most promising model in the prediction of the TC and E.C concentration, s followed by the RBF and MLR models, respectively