A new Solar Desalination System Design and Heat Recovery

The work evaluates experimentally technique toimprove fresh water production by careful energy recovery inthe vapour condensation processes; the recovered heat in turnon drives additional evaporation and preheats the feedwater. Apilot plant is designed and constructed in an arid area with 2 m2solar evaporation collector area to evaluate the process. Thisunit is tested on cold and hot days. The effect of mainparameters on fresh water production of the unit is studied. Theexperimental results show that, the production rate andefficiency of the system are strongly affected by solar radiationand level water in solar evaporation collector. Within the studiedranges, the maximum productivity reached to 16.1 kg/ m2day atTvap,av = 87.6 oC , solar radiation 842 W/m2 and level water 1.912kg. According to these results, fresher water production of thepresent system is higher than that solar still desalination systemin the previous studies

Thermal Analysis of a Hybrid Air Conditioning System with Geothermal Energy

Hybrid air conditioning systems can allow significant energy saving and emissions reductions with respect to conventional air-conditioning systems. Thermal analysis of a desiccant wheel, a heat exchanger, a ground source circulation system, and a solar collector for a hybrid air conditioning system is performed in this study. The effects of these parameters have been studied: Inlet air temperature, Inlet air humidity ratio, wheel speed, regeneration temperature, regeneration mass flowrate, heat exchanger effectiveness, ground source circulation effectiveness, and solar radiation on the behavior of the outlet air temperature and the outlet air humidity ratio from the desiccant wheel, the area of solar air collector, the solar collector efficiency, the cooling coil load, and the coefficient of performance. The hybrid system is more efficient than the vapor compression system. The hybrid system significantly decreases the cooling coil load, the cooling coil load of the hybrid system is approximately 48 % lower than the vapor compression system

Performance Enhancement of Double Tube Heat Exchanger Using Coiled Fins

The effect of inserting coil wire in the shell side of a doublepipe heat exchanger on the heat transfer and pressure drop areexperimentally investigated. The experiments are performedusing water as the hot and cold working fluid under the turbulentflow condition. Nine coils with different wire diameter (dw = 2, 4and 6 mm) and different coil pitch ratio (P/ dw = 2.5, 5 and 7.5)are used in the study. Results presented an increasing up to 1.59in the heat transfer coefficient while the pressure drop increased10 times compared with the smooth pipe. Results also showedthat the increase in the heat gain is very big than the loss in thepumping power

Investigation of the Axial Rotor Thrust in Centrifugal Compressors استقصاء الدفع المحورى على العضور الدوار فى الضواغط النابذة

الهدف من البحث هو دراسة وتحليل والتعين الدقيق للدفع المحورى علىالعضو الدوار فى الضواغط الطاردة المرکزية. نشرح العوامل التى تؤثر علىالدفع المحورى مثل زيادة الأحمال على ضاغط ثانى أکسيد الکربون عنأوضاع التشغيل التصميمية له . کما تتضمن العوامل تأثير وجود Fouling مع الغاز مما ينتج عنه تراکم على الأسطح الداخلية لدفاعات العضو الدوارفيتسبب فى زيادة الدفع المحورى وتقليل من أداء الضاغط . يتناول البحثشرح العلاقة مابين الدفع المحورى للعضو الدوارفى وجود نسبة Foulingمع الغاز فى خلال فترة زمنية محددة من بعد عمل عمرة کاملة لضاغط ثانىأکسيد الکربون . بعد الدراسة والتحليل نقف على کيفية تقليل الدفع المحورىعلى العضو الدوار وذلک بوضع اسطوانة اتزان على العضور الدوار لخلققوى معاکسة له تتناسب مع جميع الظروف التشغيلية لضاغط ثانى أکسيدالکربون بحيث أن الدفع المحورى للعضو الدوار بعدها لا يتعدى 50 % منحمل الکرسى. النتائج النهائية التى تم الحصول عليها: عند استخدام قطراسطوانة اتزان = 158.6686 mmt D تکون أعلى قيمة للدفع المحورى عنأوضاع التشغيل المختلفة للضاغط هى 93.193 % من حمل الکرسى. عنداستخدام قطر اسطوانة اتزان = 186.065 mmt D تکون أعلى قيمة للدفعالمحورى عن أوضاع التشغيل المختلفة للضاغط هى 73.35 % من حملالکرسى. عند استخدام قطر اسطوانة اتزان = 174.595 mmt D تکونأعلى قيمة للدفع المحورى عن أوضاع التشغيل المختلفة للضاغط هى41.22 % من حمل الکرسى مع وجود Fouling مع الغاز وعند أقصى حملللضاغط بعد العمرة فى عدم وجود Fouling مع الغازهى 0 % من حملالکرسى وهذا يعتبرأنسب قطر يستخدم لاسطوانة الاتزان (Balance drum)لان الدفع المحورى يکون أقل من % 50 من حمل الکرسى.Abstract: This article is a study, analysis, and determine accurately the axial rotor thrust for centrifugal compressors. Are explained the factors that affect axial rotor for carbon dioxide compressor during operating conditions. Also, the effect of the existence of fouling with gas, results in the accumulation of fouling on the internal surfaces of the impellers leading to an increase in axial rotor thrust and reduction of the performance of the compressor. The relationship between axial rotor thrust and fouling ratio with time is discussed after complete overhaul for the carbon dioxide compressor. The axial rotor thrust on the carbon dioxide compressor is reduced by placing balance drum on rotor of the compressor in the opposite direction of the axial force which is suitable for all operating conditions of the compressor. The resultant axial force didn’t exceed 50 % of rated bearing load, and the analysis method is then approved to be effective. The residual thrust load for high pressure rotor for the compressor before modification at design operating condition is equal to 13.68 % of rated bearing load, while at the high load without fouling effect for the compressor is equal to 58.47 % of rated bearing load and compressor with fouling effect is equal to 110.9 % of rated bearing load. When using the balance drum diameter Dt =158.6686 mm, the highest value of axial thrust force is equal to 93.193 % of rated bearing load. When using the balance drum diameter Dt =174.595 mm, the highest value of axial thrust force is equal to 41.22 % of rated bearing load. When using the balance drum diameter Dt =186.065 mm, the highest value of axial thrust force is equal to 73.35 % of rated bearing load