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The Gas Turbine Modular Helium Reactor (GT-MHR) uses two compression stages to compress the helium and a pre-cooler and an intercooler to reduce the compressors inlet temperature, that dissipate around 308.36 MWth at the design operational conditions. This dissipated thermal energy can be used as an energy source to produce hydrogen. An energy analysis is conducted for a proposed system that includes GT-MHR combined with Organic Rankine Cycle (GT-MHR/ORC) and a Proton Exchange Membrane (PEM) electrolyzer (GT-MHR/ORC-PEM) for hydrogen production. The optimum operating parameters values of the new cycle are obtained using the Engineering Equation Solver (EES) software. Thermal efficiency has been improved from 48.6% for the simple GT-MHR cycle to 49.8% for the new combined (GT-MHR/ORC-PEM) cycle including hydrogen production at a rate of 0.0644 kg/s at the same operating conditions. However, the thermal efficiency for the combined GT-MHR/ORC was higher and reaches 50.68%. Moreover, a parametric study is carried out over a wide range of some operating conditions such as turbine inlet temperature, Compressor pressure ratio and compressor inlet temperature to investigate their effect on the new cycle performance. Results revealed that increasing the low-pressure compressor inlet temperature increases the amount of hydrogen produced while decreasing thermal efficiencies for the three cycles. Furthermore, increasing compressor pressure ratio reduces the mass flow rate of hydrogen produced util it reaches a minimum value then it starts to increase slightly, on the contrary, an opposite relationship is observed between thermal efficiencies and compressor pressure ratio. Moreover, at low compressor pressure ratio, the rate of hydrogen produced increases with increasing turbine inlet temperature; however, it decreases by increasing the turbine inlet temperature at high compressor pressure ratio. Nevertheless, a direct correlation is noticed between thermal efficiencies and turbine inlet temperature.

In most data centers, performance reliability is often ensured by setting the amount of airflow provided by the cooling units to substantially exceed that which is needed by the IT equipment. This overly conservative strategy requires additional energy expenditure, which inevitably results in a huge amount of energy being wasted by the cooling system. To eliminate adopting such wasteful policies, conducting proper management of airflow, temperature, and energy is critical. To that end, this work proposes a novel approach to developing a compact IT equipment model at off-design conditions. This model is designed to support thermal and energy management functions in data centers. The benefit of this model is that it can accurately predict not only the IT equipment power consumption, but also the amount of flowrate required for the equipment and the air temperature leaving the equipment. While the compact model’s power consumption was derived as a function of CPU utilization, its flowrate demand and exhaust temperature were obtained from a dynamic detailed CFD model. Results from the compact model were validated with experiments where the maximum mismatch was found to be 5.7% in the outlet temperature field and 11.4% in flowrate. Compared to a state-of-the-art IT equipment compact model, the developed model was found to reduce the prediction error of the equipment’s flowrate and outlet air temperature by up to 5.2% and 9.3 % that of the state-of-the-art IT equipment compact model, respectively.

With the remarkable surge in IT power densities and energy consumption, the data center industry is starting to adopt energy and thermally-efficient single-phase cooling technologies. For many legacy data centers worldwide, the lack of a primary chilled water source is a substantial barrier to adopting single-phase technologies. In this study, the necessity of having a facility chilled water source for deploying liquid cooling solutions is eliminated by introducing a solution that does not require bringing in any modification of the data center layout. This simple solution proposes integrating liquid to air heat exchangers with the floor tiles to eject heat from the liquid-cooled IT equipment into the room air. An experimentally validated CFD modeling approach is used to investigate the performance of these heat exchangers. Results show that by installing two heat exchangers in different cold aisles, a significant amount of cooling load is handled at the design point conditions. When they are tested under different operational conditions, the cooling capacity of these heat exchangers is shown to be sensitive to the supply air temperature. To overcome the operational constraints stemming from the supply air temperature, an alternative configuration with just one heat exchanger installed in the hot aisle is considered and discussed. Results indicate that the second configuration shows superior performance to the first one in terms of sensitivity to supply air temperature and cooling capacity. Lastly, with this configuration, the data center utilizes energy extremely efficiently and achieves a power usage effectiveness of 1.06.

In this study, the Al-Qatrana powerplant of Jordan, comprising a combined cycle, was integrated with a proposed solar power and thermal energy storage system. This study aims to conduct a comprehensive transient analysis and introduce an operating methodology for the smooth transition between the different system’s operating modes. First, a comparison between the conventional powerplant and the proposed system was presented. Results showed that the integration could lead to a 41 MW improvement in output power, a 10.2 % increase in efficiency, and a 9.2 % relative decrease in SFC at design conditions. After that, shaving the summer peak load of the year 2040 using the proposed system was investigated, following the Jordanian National Electric Power Company vision, where the existing plant will be incapable of coping with the load demand. Hence, the solar and storage systems were utilized to boost the plant’s power. The system was able to meet the 2040 summer peak load and overcome the challenges that stem from the dynamic nature of the load demand and the solar radiation availability. Finally, a feasibility analysis was conducted, the results showed that the return of investment period is 8.58 years, which is encouraging.

This study reports on the essential forced air-cooled electronics issue of fan performance deterioration caused by the presence of obstructions inside Information Technology Equipment (ITE). Fan performance was characterized based on the fan's static pressure and flowrate. Three different experimental techniques (flow test chamber, pressure probe, and pressure taps) were used to measure the fan static pressure at different locations. Moreover, Computational Fluid Dynamics (CFD) models were built considering different fan working environments. Multi Reference Frame (MRF) and Lumped Fan (LF) model CFD techniques were employed. The experimental results were used to evaluate the modeling techniques whilst implemented in different working environments and to better understand how fans react to blockages inside ITE. Experiments showed that compared to the Free Environment (FE) readings, placing the fan inside a specific ITE reduced the flowrate delivered by the fan by 57.2% and decreased static pressure by 76.3%, which affects the thermal performance of the ITE cooling system. Moreover, comparing numerical results with the experimental ones showed that the MRF approach predicted the flowrate delivered by the fan with a relative error of 3.9%, while the LF approach overestimated the flowrate by 70.3%. The results and conclusions reported in this work can be expanded to cover many other applications in which fans are operating inside enclosed environments and surrounded by many obstructions.

This investigation focuses on improving the airflow distribution in data centers. In many data centers vortices form in the plenum during operations. These vortices cause spatial and temporal non-uniformities and may give rise to hot regions in the data center which in turn impacts performance and reliability of the IT equipment. The current study identifies a novel approach using porous partitions in the plenum and demonstrates a significant generalized approach that is easily adoptable in existing and future data centers. For improving the overall data center energy efficiency and the cooling system effectiveness by eliminating a critical source of inefficiency. The results of quantitative and qualitative analyses of the underfloor plenum pressure field, perforated tiles airflow rate, and air temperature at the rack intake side with and without partitions are presented. Different data center configurations are studied using physics-based experimentally validated Computational Fluid Dynamics (CFD) model. The CFD model results showed that the partitions eliminated the presence of vortices in the underfloor plenum and thus enabled a more uniform pressure distribution and tile airflow delivery. Regarding rack inlet temperature, the results showed that the partitions significantly improved the air temperature at the rack inlet. Finally, a geometrical parametric study is performed. An ideal design is and demonstrated to improve the Supply Heat Index (SHI) by about 10%, while the amount of IT equipment that exceeded the ASHRAE recommended supply air temperature (SAT) was reduced by about 40%, and the floor leakage was cut in half.

Many developing countries like Jordan, suffer from the lack of natural resources required to supply their energy demand. As such, maximum utilization of the available energy and renewable resources becomes a necessity. ALQatrana powerplant in Jordan; operating on a combined cycle suffers from sensitivity to ambient air temperatures and the lack of full utilization of waste heat of the flue gas. In this work, the plant was simulated using the engineering equation solver, and the simulation was validated against the actual powerplant data. A cascade of absorption and mechanical chillers for inlet air cooling, along with a CSP system were proposed. These auxiliary systems were also simulated and validated against literature, then integrated with the actual power plant cycle. Results showed that using the hybrid system for inlet air cooling with a combined cycle, can be more appealing in terms of power boosting and economical profit, compared to using either alone. The proposed system showed a relative increase in power by 22.8%, a 4.3% increased efficiency, and a relative decrease in SFC by 8.4%, compared to the actual power plant. Moreover, due to the hybrid inlet air cooling unit, the system exhibited low sensitivity to variation in ambient temperatures; hence, a stable power augmentation with relative change of only 0.9% over the range of temperatures (10–50) ℃. Additionally, compared to a duct burner integration, the proposed system, led to 6.4 million dollars annual saving in fuel consumption, with a 15% less CO2 emission for equivalent power production. A comprehensive feasibility study was also performed; showing a return of investment period equal to 5.3 years, which is very promising.

We study asymptotic proximity as t --> infinity of the Solutions of the inverse problem for a pseudo-parabolic equation with an unknown source function. The overdetermination condition is given in integral form. (C) 2003 Elsevier Inc. All rights reserved.