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A concentrating solar power (CSP) unit was designed to work as a hybrid system to supply the required energy for heat water and high intensity light. The system consists of a parabolic solar dish that reflected light in a set of optical fiber light inside a receiver. In turn, this light was transmitted to an indoor photovoltaic (PV) panels to produce electrical energy or used directly as a source of light during the day. This study revealed the following points: (i) the increased number of fiber optics, the improved efficiency of solar panel and power generated; (ii) the efficiency of the hybrid solar system was 23.62%. (iii) when the separation distance between the fiber optics and the PV module was closed, the level of the power generated becomes higher; and finally; (v) this application is more suitable for a limited area in the roof of the building.

One of the most important challenges in fluid mechanics, gas dynamics, and hydraulic machinery fields is measuring the flow velocity with high accuracy. It is more important in large systems; such as thermal power stations, large scale power generations, and combined cycle power plants. The exact estimation of the measurement uncertainty inflow velocity is extremely important in evaluating the accuracy of the measurement. This work describes the problem of estimating measurement uncertainty when there are two or more dominant components of the uncertainty budget. . Two methods, analytical and numerical methods are used to study the comparative analysis for the results of determining the expanded uncertainty of measurement using two methods: analytical method and the numerical method. The analytical method uses the law of uncertainty propagation and is based on the estimation of uncertainty values of type A and B, while the numerical technique depends on the evaluation of measured samples by the Monte Carlo method using a random number generator. The aim of this article is to show the Monte Carlo method as an alternative way to determine the distribution of individual components of the measurement uncertainty budget. Also, the measurement of liquid flow velocity by an ultrasonic method has been analyzed, which is commonly used due to high measurement accuracy and non-invasiveness. Due to the complexity of the equation defining the measured flow velocity, determining the measurement uncertainty is not an easy task.

This work presents performance study of a concentrating photovoltaic/thermal (CPV/T) collector and its efficiency to produce electric and thermal power under different operating conditions. The study covers a detailed description of flat photovoltaic/thermal (PV/T) and CPV/T systems using water as a cooling working fluid, numerical model analysis, and qualitative evaluation of thermal and electrical output. The aim of this study was to achieve higher efficiency of the photovoltaic (PV) system while reducing the cost of generating power. Concentrating photovoltaic (CPV) cells with low-cost reflectors were used to enhance the efficiency of the PV system and simultaneously reduce the cost of electricity generation. For this purpose, a linear Fresnel flat mirror (LFFM) integrated with a PV system was used for low-concentration PV cells (LCPV). To achieve the maximum benefit, water as a coolant fluid was used to study the ability of actively cooling PV cells, since the electrical power of the CPV system is significantly affected by the temperature of the PV cells. This system was characterized over the traditional PV systems via producing more electrical energy due to concentrating the solar radiation as well as cooling the PV modules and at the same time producing thermal energy that can be used in domestic applications. During the analysis of the results of the proposed system, it was found that the maximum electrical and thermal energy obtained were 170 W and 580 W, respectively, under solar concentration ratio 3 and the flow rate of the cooling water 1 kg/min. A good agreement between the theoretical and experimental results was confirmed.

Adsorption chiller technology has received much attention in the last few decades due to its advantages in utilizing low grade thermal energy and eco-friendly refrigerant. However, it has not been wide commercialized due to its low coefficient of performance (COP) and low specific cooling power (SCP) compared to conventional refrigeration technologies. This paper reviews different strategies to improve the COP and SCP of adsorption chillers. Heat recovery, mass recovery, multi-stage, multi-bed, improved adsorption structures and optimized operating conditions are discussed in this review. This study revealed that: (i) for operating conditions of low evaporative temperature, low generation temperature or high condensing temperature, a mass recovery technique is strongly recommended; (ii) in the case of intermittent cold production systems, use of constant temperature adsorption cooling cycle strategy is preferred; (iii) an appropriate cycle time and switching time are important to achieve the optimal system performance since the adsorption chiller performance is strongly dependent on the operating conditions; (iv) by employing a novel composite adsorbent material, along with improvements in heat exchanger design, advanced adsorption cycles can be a promising technology to improve adsorption chiller performance. This review highlights the need for further research to reduce chiller manufacture costs, increase power-to-mass ratio and improve understanding of dynamic long term chiller performance when driven by solar or waste thermal energy.

Hospitals and other healthcare facilities are complex environments that require a special consideration to HVAC design as in requirement a large amounts of ventilation, which leads to high amount of energy consumption. This manuscript presents a description of chilled water/ HVAC systems for health care facilities. A case study of a Farah hospital located in Amman/ Jordan was implemented to perform cooling load using radiant time series (RTS). This paper manipulates the effect of changing relative humidity with dry bulb temperature on the cooling load, power consumption and chiller selection using three types of building namely: commercial building, hospital building and green hospital building to choose the best indoor design conditions with minimum power consumption. To reduce the energy cost for chiller, a solar photovoltaic was proposed to overcome the portion of the air conditioning power requirement and reduce the demand on the electrical grid. A proposed solar photovoltaic technology unit was analyzed and modeled using a hybrid optimization model for renewable energies (HOMER) software. The results revealed that: (i) the applying green building criterion will lead to significant reduction in cooling load and power consumption up to 25%; (ii) A higher relative humidity and in design inside temperature, a lower cooling load and power consumption required, (iv) PV systems sizing depend on load data, solar radiation, battery data, inverter data and investment cost of the system, and finally (v) there is a potential to adopt solar PV as strategic and alternative option to reduce the cooling cost.

It presents a method to extract pure water from atmospheric air, which depends on intensifying the water vapor from the air. The plant was designed to perform the optimum levels to produce high quality water with minimal electricity consumption. The harvesting water was inspected and analyzed based on ISO/IEC 17025 method to check the purity of water. This study also investigates the potential of a solar powered using for atmospheric water generation (AWG) as a new option for fresh water production. A proposed solar AWG unit was assembled, analyzed and modeled using HOMER software. The results demonstrated that the water produced by the water extraction plant is pure, safe, economical, and acceptably tasting. It can be used as drinking water after treated by filter and disinfected by Ultra Violet Light (UV) technique. The feasibility analysis showed that there is a potential to adopt solar powered of AWG as strategic and alternative option for a small area; which is suffering from a shortage of drinking water.

The effect of different Ca-based additives in lignite on the sulfur removal during combustion has been examined using two Polish lignites. After demineralization, the lignite was loaded with Ca using different Ca-based compounds namely: calcium carbonate (CaCO3), calcium hydroxide Ca(OH)2 and calcium acetate Ca(CH3COO)2. Depending on the calcium compound used, the addition of Ca was by mechanical mixing or impregnation. The experiment was carried out in a laboratory scale drop-tube furnace reactor, under different O2 concentration and temperature range of 800–1100 °C. The results showed that Ca added to the lignite strongly suppressed the emission of SO2 under experimental conditions studied. The sulfur capture efficiency appeared to be independent of the calcium compound used and it increased along with the temperature rising up to 1100 °C. This may indicate that poorly dispersed Ca, prepared by mechanical mixing, offers as high efficiency in sulfur removal as Ca in ion-exchangeable form inserted by impregnation. The influence of mineral matter on the retention of SO2 during combustion was also investigated. It was found that some inorganic species inherently present in lignite, particularly calcium in natural form, reduce SO2 pollution.

This paper presents the possibility of using the numerical methods to analyze the work of hydraulic systems on the example of a cooling system of a power boiler auxiliary devices. The variety of conditions at which hydraulic system that operated in specific engineering subsystems requires an individualized approach to the model solutions that have been developed for these systems modernizing. A mathematical model of a series-parallel propagation for the cooling water was derived and iterative methods were used to solve the system of nonlinear equations. The results of numerical calculations made it possible to analyze different variants of a modernization of the studied system and to indicate its critical elements. An economic analysis of different options allows an investor to choose an optimal variant of a reconstruction of the installation.

Magnetic refrigeration is a fascinating superior choice technology as compared with traditional refrigeration that relies on a unique property of particular materials, known as the magnetocaloric effect (MCE). This paper provides a thorough understanding of different magnetic refrigeration technologies using a variety of models to evaluate the coefficient of performance (COP) and specific cooling capacity outputs. Accordingly, magnetic refrigeration models are divided into four categories: rotating, reciprocating, C-shaped magnetic refrigeration, and active magnetic regenerator. The working principles of these models were described, and their outputs were extracted and compared. Furthermore, the influence of the magnetocaloric effect, the magnetization area, and the thermodynamic processes and cycles on the efficiency of magnetic refrigeration was investigated and discussed to achieve a maximum cooling capacity. The classes of magnetocaloric magnetic materials were summarized from previous studies and their potential magnetic characteristics are emphasized. The essential characteristics of magnetic refrigeration systems are highlighted to determine the significant advantages, difficulties, drawbacks, and feasibility analyses of these systems. Moreover, a cost analysis was provided in order to judge the feasibility of these systems for commercial use.

This study presents a comparative analysis of performance, exhaust and noise emissions for a one-cylinder, four-stroke, spark-ignition engine powered by gasoline fuels of two different grades of research octane numbers (RONs), namely octane 90, and octane 95. During the experimental works, each fuel test was performed by varying the engine speed within the range from 1000 to 3600 rpm. The SI engine was connected to eddy current dynamometer with electronic control unit (ECU), an exhaust gas analyzer and the sound level meter (SLM) to determine engine performance, exhaust emissions, and measuring the sound pressure level (SPL) in decibels (dBA) and one octave frequency bands in the audible human range at different engine speeds, respectively. The experimental results showed that the using gasoline with octane grades higher than the requirement of an engine will decrease the engine performance. On average, the brake power and thermal efficiency for the SI engine fuelled with octane 90 is higher than that of gasoline octane 95 by 6% and 11% respectively, and improvement of BSFC by 14%, which is mainly due to higher heating value. Even though, the volumetric efficiency of octane 95 is more 5% than octane 90 due to higher latent heat and heat capacity. In general, the exhaust emission profiles for NOx and CO of the engine improved for octane 95 by 11% and 17% respectively. On the other side, the HC and CO2 emissions concentration of gasoline octane 90 is lower than that of gasoline octane 95 by 18% and 12% respectively. Finally, the noise levels showed a trend of the increase of disturbing for higher octane number and the increase of divergence between the two values of SPL at higher speed for both fuels.

Performance of an adsorption cooling system driven by solar thermal energy was studied under different climatic conditions. The effects of solar collector area, collector slope, hot water temperature and flow rate on the system performance were investigated using the real-time weather data of two cities: Perth, Australia (a representative city in the southern hemisphere) and Amman, Jordan (a representative city in the northern hemisphere). The simulation results showed that the two cities had similar solar radiation during the summer period and that the solar adsorption chiller could reliably provide cooling at a reasonably high system COP. For residential cooling with a total CPC (Compound Parabolic Collector) solar collector area of 36.22 m2, the average system COP was 0.491 for Perth weather conditions and 0.467 for Amman weather conditions, respectively while the cooling capacity was 10.3 kW for Perth and 8.46 kW for Amman, respectively at peak times. Optimum performance occurred when the system run with the CPC collector slope of around 30°, the solar water storage tank volume of 1.4 m3, inlet hot water temperature of 80 °C, and a hot water flow rate of 0.33 kg/s. An economic analysis was further investigated and the results showed that the solar driven adsorption cooling system could reduce the electricity consumption for Perth and Amman cities by 34% and 28%, respectively in comparison to a conventional vapour compression cooling system.

This manuscript analyzes the sub-systems of evaporative cooler (EC) combined with desiccant dehumidification and regeneration for automotive air conditioning purpose. The thermodynamic and psychometric analysis was conducted to design all evaporative cooling system components in terms of desiccant selection, regeneration process, compact heat exchanger and evaporative cooler. Moreover, the effect of the desiccant, heat exchanger and evaporative performances on the mass flow rate and water sprayed required for evaporative cooling system was investigated. The results show that the theoretical evaporative cooling design will achieve two main objectives: lower fuel consumption and less environmental pollutants. However, it has the two drawbacks in terms of increased weight and reduces the coefficient of performance (COP). The main remark is that evaporating cooling system is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter.

The energy demand for cooling and air conditioning systems is increasing worldwide, especially in regions with high solar radiation intensity. One of the reasons for this is the increase of comfort demands worldwide. The most cooling and air conditioning systems are the conventional electrically driven one type such as compression refrigeration machines and air conditioning systems. Through the huge electricity consumption for cooling and air conditioning, the environmental problems get bigger and bigger, because of carbon dioxide (CO2) and other pollutant emissions. One of the possibilities to reduce the primary energy consumption is through the use of solar energy for driving the thermal driven absorption or adsorption refrigeration systems, or desiccant cooling. Another possibility is using solar energy to produce electrical energy and this can be used to drive the conventional refrigeration systems. Many research and developmental efforts in the last years have been done to enforce the spreading of solar-driven cooling systems. This paper will illustrate the state of the art about the energy consumption for cooling and air conditioning systems, available solar-driven cooling systems and the potential of the utilization of such systems in comparison to the conventional ones. Moreover, this paper highlights some different methods of optimization, which used to maximize the performance and minimize the cost.

Performance assessment of a two-bed silica gel-water adsorption refrigeration system driven by solar thermal energy is carried out under a climatic condition typical of Perth, Australia. A Fourier series is used to simulate solar radiation based on the actual data obtained from Meteonorm software, version 7.0 for Perth, Australia. Two economic methodologies, Payback Period and Life-Cycle Saving are used to evaluate the system economics and optimize the need for solar collector areas. The analysis showed that the order of Fourier series did not have a significant impact on the simulation radiation data and a three-order Fourier series was good enough to approximate the actual solar radiation. For a typical summer day, the average cooling capacity of the chiller at peak hour (13:00) is around 11 kW while the cyclic chiller system coefficient of performance (COP) and solar system COP are around 0.5 and 0.3, respectively. The economic analysis showed that the payback period for the solar adsorption system studied was about 11 years and the optimal solar collector area was around 38 m2 if a compound parabolic collector (CPC) panel was used. The study indicated that the utilization of the solar-driven adsorption cooling is economically and technically viable for weather conditions like those in Perth, Australia.

Radiative properties of transparent insulations made of a layer of parallel, small-diameter, thin-walled, visible light transparent pipes placed perpendicularly to the surface of a flat solar absorber are investigated theoretically. A formula for the radiation heat losses through the insulation is derived based on two main assumptions: the system is in steady-state and the fourth power of the temperature along each pipe is linear. Arguments in favor of the assumptions are given. The formula, combined with standard formulas for the conductive heat flux, enables prediction that a 10 cm thick transparent insulation under insolation of 1000 W/m2, at ambient temperature 20 °C, could theoretically raise the absorber temperature to 429 °C and produce 410 W mechanical power under the ideal Carnot cycle. In order to reach that high energy conversion efficiency, the insulation pipes should have diameter less than 0.5 mm and walls about 5 μm thick, which may be technologically challenging.

The adsorption chiller technology makes possible to construct the chillers that can be powered by a low temperature heat source, which improves the efficiency of the energy and minimises the level of environmental pollutions. It has been found that adsorption chillers are valuable when the heat source is affordable as cogeneration, solar, geothermal, or waste heat sources, especially in situations when the heat is partially dissipated in the environment. On the other hand, adsorption chillers are non-competitive if the heat is delivered from dedicated combustion of fossil fuels, hence the relatively low COP of adsorption chillers against compressor chillers. For this reason, it was proposed and tested three-beds with dual evaporators of 100 kW adsorption chiller driven with low temperature heat from cogeneration. In order to achieve the highest performance, the switching time was optimized. It was found that the best adsorption performance is at switching time of about 900 sec to get the highest COP around 0.645 and total cooling capacity around 90.5 kW.

A mathematical model was developed to investigate the effect of crucial operating parameters, such as process inlet humidity ratio, inlet volume flow rate, R/P ratio (reactivation/process air flow), regenerative temperature and rotational speed on the performance of desiccant wheels in hot and humid climates, using wound silica gel and molecular sieve desiccants. The desiccant wheels were designed to operate in two modes, specifically, with 90° for reactivation and 270° for process (1:3 split) as well as with 180° for reactivation and 180° for process (1:1 split). The main results enabled to make the following observations: (i) higher regeneration air temperature leads to an improvement of dehumidification and reduction of the thermal coefficient of performance COPth, (ii) an increase in the process inlet volume flow rate causes a reduction in the process removed moisture; (iii) the greater R/P ratio is required to remove more moisture, while a lower R/P ratio implies the lower power consumption for regeneration; (iv) silica gel desiccant is preferred when greater moisture removal is required at high inlet relative humidity, while molecular sieve desiccant is preferred when low dew point is required at low inlet relative humidity. Keywords: Moisture, Desiccant, Cooling system, Silica gel, Molecular sieve, Indoor humidity

The use of a variable refrigerant flow (VRF) is being specified as an alternative solution to centralize HVAC systems in domestic building. This manuscript presents a comprehensive description of the configuration for the indoor and outdoor units of a multi-split VRF system. A case study of a hotel in Amman, Jordan was implemented. The suitable indoor and outdoor units were selected according to heating and cooling load. A sensitivity analysis of the effect of some parameters on heating and cooling loads were analyzed. Finally, the thermal human comfort indices of PMV and PPD were investigated. This study showed that even the main shortcoming of using VRF system due to its high initial cost, but this system is encouraged especially in small places due to its energy efficiency appeal at partial loads, satisfying optimum thermal human comfort, and a good substitute where scarcity of water and achieving more thermal human comfort. Keywords: VRF system, Air conditioning, Cooling, Heating, Human comfort, PMV, PPD, HAP program