volume-17-Issue 1 (2020)
Latest Articles
Mathematical Modelling for the Thermal Performance of a Solar Parabolic Trough Concentrator (PTC) Under Egypt Climate
IJTEE, volume-17, Issue 1 (2020) , PP 51 - 58
Published: 06 Dec 2020
DOI: 10.5383/ijtee.17.01.006
by Mohamed H. Ahmed , Alberto Giaconia , Amr. M. A. Amin from Solar Energy Department, National Research Centre, Dokki, Giza, Egypt Energy Technologies Department, ENEA Casaccia Research Center, Roma, Italy Academy of Scientific Research and Technology, Cairo, Egypt
Abstract: In this work, an analysis of the annual performance of a parabolic trough concentrator has been accomplished. A numerical model was developed and built to study the annual performance of the parabolic trough collector's field at different locations in Egypt. The energy equations were solved using the Engineering Equation Solver EES software. The optical and thermal parameters of the concentrator were considered in the model. The numerical model results showed that temperature rise ranges from 90.5 to 221 °C and the outlet temperate ranges from 442 to 565 ºC at solar noon according to the season and the location. The operating period of the parabolic concentrator reaches its maximum value at summer where it ranges from 76.5 to 82 h/week. The present model was validated with the TRNSYS model. As a result, the presented model can be considered as a meaningful tool for developing the parabolic trough plant in Egypt. read more... read less...
Keywords: Solar Plant, Numerical Model, Parabolic Trough Collector, Collector Efficiency, Annual Performance, Model Validation
Impact of Storage Tank Size and Backup Heating Unit on a Solar Absorption Cooling System
IJTEE, volume-17, Issue 1 (2020) , PP 41 - 50
Published: 06 Dec 2020
DOI: 10.5383/ijtee.17.01.005
by Mohamed H. Ahmed from Solar Energy Department, National Research Center, Giza 12622, Egypt
Abstract: Solar energy has a great ability in cooling and air conditioning as the demand for cooling and air conditioning coincides with the availability of solar energy. In this study, a simulation program using TRNSYS platform was built to simulate and optimize the design and operating parameters. The hourly thermal performance of a single stage LiBr/H 2O solar absorption cooling system powered by linear Fresnel Concentrator was investigated under Cairo climate. The components size of the solar absorption cooling plant was optimized. The performance of the cooling system was studied in terms of the rate of useful energy from the concentrator, of the collector outlet temperature, and the coefficient of the performance COP of the absorption chiller. From the study, it was found that the optimum storage tank capacity depends on the area of the solar concentrator. Increasing the storage tank capacity from 3 to 9 m 3 leads to a decrease in the maximum outlet temperature from the collector from 182 to 120 ºC and consequently decreasing the Absorption chiller COP from 0.46 to0.07 respectively. Supplying a gas backup heating unit ensures stability for powering the adsorption cooling system. Increasing the backup unit capacity increase the operating hours of the absorption chiller. read more... read less...
Keywords: Solar Cooling, Absorption, Linear Fresnel Concentrator, Simulation, Storage Tank, TRNSYS
Efficient Residential Buildings in Hot and Humid Regions: The Case of Abu Dhabi, UAE
IJTEE, volume-17, Issue 1 (2020) , PP 29 - 40
Published: 06 Dec 2020
DOI: 10.5383/ijtee.17.01.004
by Ayesha AlQubaisi, Ali Al-Alili from Department of Mechanical Engineering, Khalifa University, Sas Al Nakhl Campus, Abu Dhabi, UAE
Abstract: The design, construction, and operation of highly efficient residential buildings in hot and humid climates represent a unique challenge for architects, contractors, and building owners. In this paper, a case study on the performance of a residential building located in hot and humid region is presented. The building is a single-family house, which is modeled as a multi-zone building. The transient systems simulation program (TRNSYS) is used to simulate the building under Abu Dhabi’s typical meteorological year conditions. The main objective of this paper is to investigate the effects of applying different standards and building codes such as LEED, ASHRAE and Estidama for hot and humid regions on the energy performance of the building. The energy consumption of the building includes different equipment namely: air conditioners, lighting and electric water heaters. The building thermal analysis is extended to include the occupants thermal comfort analysis using different building codes. Moreover, the environmental impacts upon selecting Estidama for hot and humid regions will be discussed. read more... read less...
Keywords: Green building rating; Estidama; LEED; Energy Efficiency; Thermal comfort
Boosting Regulations Legislation Reliefs Regarding Environmental Management Systems in the Framework of EMAS and ISO 14001: Case Study of Cyprus
IJTEE, volume-17, Issue 1 (2020) , PP 19 - 27
Published: 06 Dec 2020
DOI: 10.5383/ijtee.17.01.003
by Loizia Pantelitsa , Voukkali Irene , Antonis A. Zorpas from ENVITECH (Environmental Technology) Ltd, Institute of Environmental Technology and Sustainable Development, Department of Research – Development, Paralimni, Cyprus Cyprus Open University, Faculty of Pure and Applied Sciences, Environmental Conservation and Management, Laboratory of Chemical Engineering and Engineering Sustainability Nicosia, Cyprus
Abstract: Environmental Management Systems (EMS) defining a list of requirements that can help organizations to improve their environmental performance. The most common well-known standards are ISO 14001 and EMAS, which both are in a voluntary base. Beside the National Legislation in Cyprus (N.761/2001) there is no any relief document that introduced EMAS Regulation (EC) N. 1221/2009.However, there is an increasing pressure on firms, from a number of different sources (i.e. global market requirements, legislative indirect pressure, customer’s satisfaction etc.), to engage in environmental management initiatives. The aim of this study is to evaluate the incentives as well as the difficulties that Small Medium Enterprises (SMEs) which are located in Cyprus and other European countries (i.e. Italy, Chez Republic and Slovenia) that are facing during the implementation of EMS. The preliminary results indicated that in the case of Cyprus, there are not any specific regulatory reliefs besides some funding programs to convince SMEs to implement and maintain EMAS as well as ISO 14001. On the other hand, in several EU countries there are some more solids measures to encourage SMEs to adopt EMAS. read more... read less...
Keywords: EMAS legislation, ISO 14001 legislation, BRAVER.
Greenhouse Microclimate Flow Simulation: Influence of Inlet Flow Conditions
IJTEE, volume-17, Issue 1 (2020) , PP 11 - 18
Published: 06 Dec 2020
DOI: 10.5383/ijtee.17.01.002
by Syed Shabbar Raza, Khadije El Kadi, Isam Janajreh from Mechanical Engineering Department, Khalifa University of Science and Technology, Masdar City, Abu Dhabi, UAE
Abstract: Greenhouse (GH) has been demonstrated as a profitable technology for food production with low demand of irrigation water. In this work, a numerical model is developed to study the micro-climatic environmental conditions inside a greenhouse distillation system for optimize operation. The system performance (temperatures, flow velocities, relative humidity) is presented and improvement factors for the system performance are suggested. The result shows that the inlet velocity and plant transpiration have a more pronounced effect on the relative humidity than the incoming temperature variation. As temperature increases by 8C o the relative humidity decreases with few percentiles (~2%). When velocity varies between 0.2-0.7m/s, and within the diurnal operation of the GH, an increase of up to 5 points in the humidity is observed. Finally, when the transpiration increases from 0.2 to 1.2 g/m 3 the relative humidity observes a drastic jump of over 15 points. read more... read less...
Keywords: Sustainable Greenhouses, CFD, HVAC, Plant Transpiration
Comparing Between Best Energy Efficient Techniques Worldwide with Existing Solution Implemented in Al-Ahliyya Amman University
IJTEE, volume-17, Issue 1 (2020) , PP 1 - 10
Published: 06 Dec 2020
DOI: 10.5383/ijtee.17.01.001
by Ammar Alkhalidi, Walaa Hassan from Energy Engineering Department, German Jordanian University, Amman, Jordan Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan
Abstract: In this research paper, an overview of energy reduction methods around the world in commercial buildings was investigated, to find out the best solution for minimizing electricity demand of Al-Ahliyya Amman University (AAU).Those methods are renewable energy technologies mainly wind and photovoltaics (PV) system using either conventional or Carbon Nanotubes panels, building envelope system mainly dynamic Insulation materials and cool roof coating and National country system mainly demand response program and energy consumption ration. According to the overview, the best-promised method solution to achieve the target of saving, reducing investment cost and carbon emissions in AAUis the Standalone Hybrid Carbon Nanotubes PV system. This method was compared with the existing on-grid PV system project applied in AAU. The comparison was based on investment cost, payback period and solar cell efficiency. The comparison analysis results revealed that Standalone Carbon Nanotube PV system was able to save 21.12% of the investment cost when compared to the existing AAU project with a reduced payback period from 10 to 8 years and Internal Rate of Return (IRR) of 16%. read more... read less...
Keywords: carbon Nanotube PV system, Energy Efficient Techniques, Amman Jordan.