volume-02-Issue 1 (2010)
Latest Articles
Effect of the Storage Capacity and Solar Collectors Area on the Performance of Space Heating System using a Solar Heat Pump
IJTEE, volume-02, Issue 1 (2010) , PP 55 - 60
Published: 27 Jan 2010
DOI: 10.5383/ijtee.02.01.008
by Rabah GOMRI, Mourad BOULKAMAH from Laboratory of Génie Climatique, Faculty of Engineering, Department of Génie Climatique, University of Constantine, 25000 Constantine, Algeria
Abstract: The purpose of this work is the study, the simulation, and the analysis of a solar flat plate collector combined with a compression heat pump. The system suggested must ensure the heating of a building without the recourse to an auxiliary energy source in complement of this heating system. A numerical model is developed to study the influence of the volume of storage tank and the area of the solar collectors on the performance of the system. The system is used to heat a building using heating floor. The building considered is located in Constantine-East of Algeria (Latitude 36.28°N, Longitude 6.62°E, Altitude 689m). For the calculation, the month of February was chosen, which is considered as the coldest month according to the weather data of Constantine read more... read less...
Keywords: Heat pump, Flat plate solar collectors, Storage Tank, Space heating.
Alternative Energy Sources in Turkey for Sustainable Development
IJTEE, volume-02, Issue 1 (2010) , PP 49 - 54
Published: 27 Jan 2010
DOI: 10.5383/ijtee.02.01.007
by Mehmet Emin Argun, Yusuf Alparslan Argun from Selcuk University, Engineering Faculty, Environmental Engineering Dept., Konya, Turkey, Aksaray University, Institute of Science, Environmental Engineering Dept., Turkey
Abstract: This study is focused on the potential alterative and renewable energy sources for Turkey. A lot of alternative energy sources present in the world as well as in Turkey including hydro, solar, wind, geothermal and biomass energy. However, we can use a few amount of this sources although they can meets of world’s energy need on a large scale. Alternative energy usage has also potential to decrease CO2 emission which is responsible of global warming. Low productivity, high investment and operational cost of these methods minimize their application in a wide range. Therefore, many studies have been carried out to decline the costs and to improve the efficiency of these systems read more... read less...
Keywords: Alternative energy source, hydropower, solar, wind, geothermal, biomass, sustainability
Development of Intermediate Pressure Correlation for the Half-Effect Absorption Cooling Chiller
IJTEE, volume-02, Issue 1 (2010) , PP 35 - 40
Published: 27 Jan 2010
DOI: 10.5383/ijtee.02.01.005
by Rabah GOMR from Laboratory of «Génie Climatique», Faculty of Engineering, Department of «Génie Climatique , University of Constantine, 25000 Constantine, Algeria
Abstract: This paper investigates the two stage half-effect absorption system. The main components of this system are: the condenser, the evaporator, the two generators (low pressure generator and high-pressure generator) and the two absorbers (low pressure absorber and high-pressure absorber). The evaporator and low-pressure absorber operate at low pressure (evaporation pressure Pav). The low generator pressure and high absorber pressure operate at intermediate pressure (Pi) and the high generator pressure and the condenser operate at high pressure (condenser pressure, Pcd). For a given set of generators, evaporator, condenser and absorbers temperatures, the intermediate pressure (Pi) must be optimized to get a maximum coefficient of performance ‘COP’ and exergy efficiency of the system. This paper enables us to obtain immediately the intermediate pressure, Pi through a newly developed correlation. This correlation is valid for a commonly used chilled water temperature (12°C/7°C) when the evaporation temperature is maintained at 4°C, condenser and absorber temperatures are varied from 28°C to 38°C and generator temperature is varied from 40°C to 80°C. It is found that the maximum COP values of the half-effect cooling systems are in the range of 0.41–0.43 and the maximum energetic efficiency for half-effect cooling systems are in the range of 14.7%–22.6%. read more... read less...
Keywords: Absorption ,Cooling Half-effect , Intermediate Pressure , Correlation , Efficiencies.
Indoor Energy Analysis of Food Distribution Warehouse
IJTEE, volume-02, Issue 1 (2010) , PP 27 - 34
Published: 27 Jan 2010
DOI: 10.5383/ijtee.02.01.004
by Rafat Al-Waked, Nathan Groenhout, Lester Partridge from Prince Mohammad Bin Fahd University, Al-Khobar, Kingdom of Saudi Arabia, 31952, AECOM Buildings Group, South Brisbane Area, Queensland, Australia, 4006, AECOM Buildings, Sydney NSW, Australia, 2000
Abstract: The current investigation involves carrying out dynamic thermal simulations and computational fluid dynamic analysis (CFD) analysis. The purpose of this analysis is to assist in designing a ventilation system to achieve an acceptable internal thermal environment of less than 28 º C dry bulb temperatures within the occupied space. The thermal performance of the facility over a period of time has been simulated taking into account the effect of thermal mass within the space which affects the average internal space temperatures. Results from the dynamic thermal simulation analysis were then used to provide the boundary conditions for the CFD analysis. The investigated warehouse has been simulated using four different roofs based mechanical ventilation strategies. The amount of goods stored in the warehouse has been found to play a significant role in keeping the warehouse temperature within the acceptable range. An almost empty warehouse tends to vary with the outside ambient temperature. However, a warehouse full of goods makes use of thermal mass to provide a passive cooling strategy. It is recommended that mechanical ventilation of 350 m3 /s of air to be adopted using the smoking fans already exist in the warehouse. These fans should operate when the ambient temperature falls below 27ºC at any time of the day if the temperature requirements are satisfied during the summer period read more... read less...
Keywords: Energy Analysis, CFD, Indoor Environment, Ventilation, Thermal Simulation
Acoustics Vibrations to Enhance Flow Boiling in Micro Channels
IJTEE, volume-02, Issue 1 (2010) , PP 19 - 25
Published: 27 Jan 2010
DOI: 10.5383/ijtee.02.01.003
by Yasir M. Shariff from Mechanical Engineering Department, Taibah University, Madina, Saudi Arabia
Abstract: Heat transfer coefficients were measured for forced convection refrigerant mixture (R-407C) flow in micro channels enhanced by acoustics vibration. Flow in horizontal micro channels (ID 100.0 m), and a length of 50 mm for subcooled and saturated boiling conditions are reported in this study. Experiments were conducted at a heat flux of 6 kW/m2 for subcooled boiling saturated boiling was carried at heat fluxes of 15 and 29 kW/m2. The mass flow rate was varied from 0.45 to 1.85 kg/min. The frequency was varied, freq= 5, 10, and 15 kHz. An experimental setup composed of heating elements provided heat flux variations in the micro channels and excitation elements were attached to the side of the channels to produce the acoustics vibrations. The heat transfer coefficient was found to be dependent on both the heat flux as well as mass flux levels. Results show that acoustics vibration enhanced the heat transfer performance by 21% as compared to regular flow convective boiling process. read more... read less...
Keywords: Micro Channels, Flow Boiling, Enhancement, Acoustics, Refrigerant Mixture
Energy-Efficiency in Air Conditioned Buildings: The Green Buildings Dream
IJTEE, volume-02, Issue 1 (2010) , PP 9 - 18
Published: 27 Jan 2010
DOI: 10.5383/ijtee.02.01.002
by Essam E. Khalil from Department of Mechanical Engineering, Cairo University, Egypt
Abstract: To design an optimum HVAC airside system that provides comfort and air quality in the air-conditioned spaces with efficient energy consumption is a great challenge. This paper evaluates recent progresses of HVAC airside design for the air-conditioned spaces. The present evaluation study defines the current status, future requirements, and expectations. It has been found that, the experimental investigations should be considered in the new trend of studies, not to validate the numerical tools only, but also to provide a complete database of the airflow characteristics in the air-conditioned spaces. Based on this analysis and the vast progress of computers and associated software, the artificial intelligent technique will be a competitor candidate to the experimental and numerical techniques. Finally, the researches that relate between the different designs of the HVAC systems and energy consumption should concern with the optimization of airside design as the expected target to enhance the indoor environment. read more... read less...
Keywords: HVAC Design, Energy Efficiency, Air Quality, Comfort
Design of a Bubble Pump Cooling System Demonstration Unit
IJTEE, volume-02, Issue 1 (2010) , PP 1 - 8
Published: 27 Jan 2010
DOI: 10.5383/ijtee.02.01.001
by H.I. Abu-Mulaweh, D.W. Mueller, B. Wegmann, K. Speith, B. Boehne from Purdue University at Fort Wayne, Fort Wayne, IN 46805, USA
Abstract: The aim of this study is to examine the feasibility of developing a bubble pump cooling system prototype that can dissipate a certain amount of heat generated by an insulated gate bipolar transistor. To this end, a bubble pump cooling system prototype was designed and developed. The performance of the bubble heat pump cooling system prototype is described by presenting some experimental test data. This paper provides details about the design and development of the heat pump cooling system prototype, as well as testing and validation of this unit. read more... read less...
Keywords: Bubble Pump, Design, Cooling System