Optimization of a hybrid combination of a photovoltaic syste and a wind energy conversion system: İzmir Institute of Technology Campus area case

Thesis (Master)--Izmir Institute of Technology, Energy Engineering, Izmir, 2003Includes bibliographical references (leaves: 69-75)Text in English; Abstract: Turkish and Englishxii, 90 leavesRenewable energy resources have gained the great importance due to the growing concerns of environmental problems. The integrated utilization of renewable energies such assolar and wind are becoming very attractive, especially, in most of the isolated and remote areas in many parts of the world.In the present study, firstly, wind and solar radiation measurements, made on Izmir Institute of Technology (IZTECH) Campus area, have been analyzed in order to determine the, both, solar and wind energy potentials of the location. The monthly average wind speeds range from 5.7 m/s to 7.7 m/s, the monthly average of daily values of solar radiation range from 2.1 kWh/m2 to 5.7 kWh/m2 at the monitoring station throughout the measurement period of 12 months between 01.01.2002 and 31.12.2002.Secondly, a procedure is described which determines the hybrid system parameters such as photovoltaic (PV) array area and rotor swept area of wind turbine while satisfying a specific load distribution. The employed method is a graphical construction to figure out the optimum configuration of the generators that satisfies the energy demand mentioned above

Refrigeration System: Capacity Modulation Methods

Energy conservation and reduction of the global warming effect become one of the most important subjects in the world. Since refrigeration system energy consumption is steadily increasing in overall energy consumption, this system is under research. Refrigeration systems are full of energy conservation that is having minimum energy consumption while satisfying the user’s needs. Refrigeration system applications where the load may vary over a wide range, due to lighting, product loading, ambient weather variations, or other factors during operation, can be optimized by capacity modulation. There are many ways to achieve capacity modulation. This paper presents literature review of various capacity modulation methods which reduce the energy consumption of the refrigeration system and decrease CO2 emission indirectly. In this paper, on/off control, digital scroll compressor, cylinder unloading, hot gas bypass, slide valve, multiple compressor, and variable speed capacity control methods are presented. In addition, electrical control techniques for the refrigeration capacity modulation applications are summarized

Operation of Compressor and Electronic Expansion Valve via Different Controllers

WOS: 00039941330001

The Journal of MacroTrends in Energy and Sustainability Improving the Energy Output of a Geothermal/Solar Hybride Energy System

Abstract In these days Renewable Energy Sources (RES) are becoming increasingly more popular. The key reason for this is, perhaps, the increase of prices in fuel oils and other fossil based energy resources. Another effect is the increase of global warming. This work shows the improvement of a Hybrid Electrical Power Plant which is controlled b

Performance evaluation of a building integrated photovoltaic (BIPV) system combined with a wastewater source heat pump (WWSHP) system

This paper deals with both energetic and exergetic performance assessments of two combined systems as a whole. The first one is a Building Integrated Photovoltaic (BIPV) system while the second one is a wastewater (WW) Source Heat Pump (WWSHP) system. Both systems were installed at Yasar University, Izmir, Turkey within the framework of EU/FP7 and the Scientific and Technological Research Council of Turkey (TUBITAK) funded projects, respectively. The BIPV system was commissioned on 8 February 2016 and has been successfully operated since then while the WWSHP system was put into operation in October 2014. The BIPV system has a total peak power of 7.44 kW and consists of a total of 48 Crystalline Silicon (c-Si) modules with a gap of 150 mm between the modules and the wall, and a peak power per PV unit of 155 Wp. The WWSHP system consists of three main sub- systems, namely (i) a WW system, (ii) a WWSHP, and (iii) an end user system. Two systems considered have been separately operated while the measured values obtained from both systems have been recorded for performance assessment purposes. In this study, a combined system was conceptually formed and the performance of the whole system was evaluated using actual operational data and some assumptions made. Exergy efficiency values for the WWSHP system and the whole system were determined to be 72.23% and 64.98% on product/fuel basis, while their functional exergy efficiencies are obtained to be 20.93% and 11.82%, respectively. It may be concluded that the methodology presented here will be very beneficial to those dealing with the design and performance analysis and evaluation of BIPV and WWHP systems

Energetic Assessment of an Electronic and a Thermostatic Expansion Valve for a Variable Capacity Compressor

 In this study, a chiller system with an electronic expansion valve (EEV) and a thermostatic expansion valve (TXV) were compared from an energy saving view under variable and fixed speed compressor. The experimental chiller system under study has a variable speed scroll compressor, EEV and TXV, air cooled condenser and auxiliary equipments. The R134a was used in the compressor as a refrigerant. Although in variable speed chiller systems usually EEVs are used, in this study a TXV was also used to compare its performance. The results of the experimental studies show that the chiller system with EEV has 30% lower superheat value and 6% lower power consumption than the chiller system with TXV under variable speed operation. From the fixed speed compressor view, the chiller system with TXV performs 1.7% lower superheat value than the chiller system with EEV and, the chiller system with EEV has 8.5% higher compressor power consumption than TXV

Techno-Economic and Environmental Assesment of Compressor Retrofitting Procedure

In this study, retrofitting of a fixed speed refrigeration system to a variable speed refrigeration system is investigated. Economical and technical benefits of the retrofitting procedure are also studied. Refrigeration systems are usually designed to overcome maximum load conditions. However, they work under partial load in most of their life cycle. Hence, in this study a variable speed compressor that equalizes the cooling load to the demand that assures significant energy saving is considered. As a result of this study, the retrofitted variable speed compressor performed 17% decreased energy consumption versus the thermostatic controlled fixed speed system. Also, the retrofitting procedure provided considerable payback time. From the result, 10750 kilograms less carbon emission per year as an environmental benefit within retrofitting procedure is obtained

Fuzzy logic control of the compressor speed and electronic expansion valve in a chiller

Günümüzde enerji tasarrufu ve küresel ısınma etkilerini azaltmak tüm dünyada en önemli konu haline gelmiştir. Elektrik dönüşüm sistemlerinin verimsiz kullanımı dolaylı olarak atmosferdeki sera gazı emisyonlarını arttırmakta ve küresel ısınmayı hızlandırmaktadır. Ayrıca soğutma sistemleri kullanımının artması nedeniyle toplam enerji tüketimdeki payı sürekli artmaktadır. Tüketim miktarlarını azaltmak için, daha verimli çalıştırılabilen evsel ve ticari iklimlendirme sistemleri kullanılmalıdır. İklimlendirme sistemlerinde, kullanıcı ihtiyacı değişmeden enerji tasarrufu yapılabilecek geniş bir potansiyel bulunmaktadır. Bu konuda en verimli olarak kullanılabilecek seçenek soğutma kapasitesinin modülasyonudur. Kapasite modülasyon yöntemleri soğutma sistemi kapasitesini yük ile eşitlemektedir. Bunun için en etkin yöntem ise, değişken hızlı kompresör kullanımıdır. Bu çalışmada temel amaç, 5 kW soğutma kapasiteli soğuk su üretim grubuna ait scroll kompresörün, PWM inverter ve bulanık mantık algoritması kullanılarak değişken hızlı olarak çalıştırılmasıdır. Aynı sistemde, termostatik ve elektronik tip genleşme vanası kullanmanın değişken hızlı sistem performansına etkisi de incelenmiştir. Deneysel çalışmanın yapıldığı soğutma sistemi kompresörü, ilk halinde sabit hızla çalışmak üzere tasarlanmıştır. Bu çalışmada ise bir invertörün ilavesi ile değişken hızlı olarak işletilmiştir. Böylece soğutma sistemlerinde yeni kontrol tekniklerinin mevcut sabit hızlı sistemlere de uygulanması ile daha verimli enerji kullanımı imkanları araştırılmıştır. Sonuç olarak, bulanık mantık kontrolun kullanıldığı değişken hızlı sistemde, açık-kapalı kontrol edilen sabit hızlı sisteme göre yüzde 17,2 COP artışı sağlanmıştır. Recently, energy conservation and reduction of the global warming effect become one of the most important subject in the worldwide. Greenhouse gas emission and global warming are increasing indirectly because of the fact that inefficient using of the refrigeration system. Refrigeration system's energy consumption is steadily increasing in overall energy consumption, since their using has been increasing. Refrigeration systems have full of energy conservation that is having minimum energy consumption while satisfying the user's needs. Energy consumption of the refrigeration system can be optimized by capacity modulation methods. These methods allow us to match the compressor refrigeration capacity to the cooling load at any time. Although there are many ways to achieve capacity modulation, variable speed capacity modulation is the most efficient method. In this thesis, variable speed capacity modulation method has been studied. The primary aim of this study is to setup a fuzzy logic controller to regulate speed of the scroll compressor used in 5 kW capacity chiller system by using PWM inverter. In addition to this, effect of the expansion valves like thermostatic and electronic on variable speed refrigeration system has been studied. The experimental setup had been designed to operate at fixed speed. During the study, to ensure variable speed, PWM inverter was added and fuzzy logic algorithm was implemented on the experimental setup. Thus ensure more energy efficient system and to apply new control techniques to the refrigeration systems has been studied by this research. As a result, variable speed compressor showed 17.2 percent COP increase according to the on-off controlled fixed speed system by using fuzzy logic control

Performance Evaluation of a Modified DC Compressor Powered by Solar Energy

 In this study, a modified direct current compressor (MDC) is tested experimentally. The experimental study is conducted in order to observe the performance of a solar energy powered MDC. Then, the performance of this MDC is compared with brand new direct current compressors (BNDC) in the market. The experimental setup has a mini fridge with 50 liters capacity, a photovoltaic panel, a battery, a charge regulator and measurement equipments. Also, a pyranometer is used to define solar radiation on the photovoltaic panel. Experiments are conducted for various cabinet loads such as no storage items, low, nominal and over load at steady state condition