Sürdürülebilir Kalkınma Amaçları

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• Kitap BölümüYalnız künye2018Scopus SJRQ3/r/bayburt/13822
  Contribution of the cogeneration systems to environment and sustainability

  Kemal, Çomakli; Uğur, Çakir; Ayşegül, Çokgez Kuş; Erol, Şahin

  The kind of energy that buildings need changes, like heating energy, cooling energy, electrical energy, and thermal energy for hot top water. Usually, the processes or systems that produce thermal energy emit pollutants while they produce heat because of the fossil fuels they use. A lower consumption of thermal energy will contribute not only to a reduction in the running costs but also in the reduction of pollutant emissions that contribute to the greenhouse effect and a lesser dependence of the hospital on the external power supply. Cogeneration or CHP (combined heat and power) is the system that produces power and usable heat simultaneously. Combined production of mechanical or electrical and thermal energy using a simple energy source, such as oil, coal, natural or liquefied gas, biomass, or the sun, affords remarkable energy savings and frequently makes it possible to operate with greater efficiency when compared to a system producing heat and power separately. Because of the life standard of humanity in new age, energy sources must be continually improved and updated. For this reason, the installation of a system for the simultaneous generation of electrical, heating, and cooling energy would be one of the best solutions if we want to have qualified energy and reduce investment and operating costs and meet ecological requirements. This study aims to bring out the contributions of cogeneration systems to the environment and sustainability by saving the energy and reducing the emissions.

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  AtıfOpenAlex1

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• Kitap BölümüYalnız künye2018Scopus SJRQ3/r/bayburt/12480
  Solar calculations of modified arch (Semi-spherical)-type greenhouse system for Bayburt City

  Uğur, Çakir; Erol, Şahin; Kemal, Çomakli; Ayşegül, Çokgez Kuş

  Solar energy is thought as the main source of all energy sources in the world, and it can be used in many applications like agricultural areas, heating-cooling or electricity production directly or indirectly. Greenhousing is the first one of the agricultural activities that solar energy can be used directly in. Greenhouses offer us suitable conditions which can be controlled easily for the growth of the plant, and they are made by using a covering material that allows the sunlight to enter into the system. Covering material can be glass, fibre glass, plastic or another transparent element. This study investigates the solar energy usability rates and solar energy benefitting rates of a semi-spherical (modified arch)-type greenhouse system according to different orientations and positions which exist under climatic conditions of Bayburt. In the concept of this study, it is tried to determine the best direction and best sizes of a semi-spherical greenhouse to get the best solar benefit from the sun. To achieve this aim, a modelling study is made by using MATLAB. However, this modelling study is run for some determined shapes and greenhouses, and it can be used for different shaped greenhouses or buildings. The basic parameters are determined as greenhouse azimuth angle, the rate of size of long edge to short and seasonal solar energy gaining of greenhouse.

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  AtıfScopus1·OpenAlex2

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• MakaleAçık Erişim2016Scopus SJRQ1/r/bayburt/12507
  Exergetic interrelation between an heat pump and components

  Çakır, Uğur; Çomaklı, Kemal

  In this study, the relation between the exergetic performance of the heat pump and its components are investigated experimentally by using an air to water heat pump. Moreover, the effects of the working conditions of the components on the exergetic performance of the system are exposed and discussed. An experimental air to water heat pump system was designed and built. The results were evaluated by comparing the components and heat pump according to their performances. 33–45% of the all destructed exergy of the heat pump system comes into existence in the compressor. The contribution of the condenser to the total exergy destruction rate of the heat pump is between 23% and 34%. Contribution of the compressor to the exergy destruction rate of heat pump decreases with an increase in the air temperature and it increases with a decrease in the air mass flow rate. Contribution of the compressor to the exergy destruction rate of heat pump decreases with an increase in the air temperature and it increases with a decrease in the air mass flow rate. In terms of exergetic performance of the heat pump, the importance and priority of the components vary with the heat source thermal conditions.

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  AtıfScopus15·WoS14·OpenAlex16

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• MakaleAçık Erişim2015Scopus SJRQ1/r/bayburt/12302
  Using solar greenhouses in cold climates and evaluating optimum type according to sizing, position and location: A case study

  Çakir, Uğur; Şahin, Erol

  This study deals with a comparison among five common greenhouse types with regard to total solar radiation gaining rates in greenhouse using season under some assumptions. Additionally, possibility of using greenhouses in cold climate regions is investigated. We analyzed five greenhouse types and developed a script in MATLAB platform for the solar radiation availability. This model is applicable and suitable for other buildings and places on the world. Even-span, uneven-span, vinery, semicircular and elliptic types of greenhouses have been analyzed. A "k" value (ratio of length to width of greenhouse) and greenhouse azimuth angle (GAA) are described. Seven different floor area are assigned for each greenhouse type such as 50m2, 100m2, 150m2, 200m2, 250m2, 300m2 and 400m2, respectively. For each floor area, k value is assigned from 1 to 10. Each greenhouse is oriented in 90 different angles according to south facade. Seasonal total solar energy gaining rates is computed individually for all possible greenhouse types, area, k number and orientation. Then a comprehensive comparison is made to determine the optimal greenhouse. The results show that greenhouses are usable and suitable for using in cold climate regions to increase the productivity. In addition, the elliptic type is the optimum one in all analyzed types of greenhouses for Bayburt conditions for all floor areas. It is followed by uneven-span, even-span, semi-circular and vinery type of greenhouses respectively. Shape and type of the roof are main effective parameters on solar energy gaining rates of greenhouses. Elliptic greenhouse should be preferred on the band of the latitude of Bayburt, unless there is restrictive factor like sizing and terrain.

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  AtıfScopus93·WoS77·OpenAlex95

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• Kitap BölümüYalnız künye2014/r/bayburt/13655
  A solar energy calculation study for the buildings in bayburt in order to get optimum benefit from the sun directly

  Çakır, Uğur; Şahin, Erol

  This study is a research made on evaluating solar energy utilization rates of the buildings and residences which are under the climatic and meteorological conditions of Bayburt. In the scope of this study, with the aim of enabling them to benefit from solar energy at the maximum level, a numerical modeling study in which we could determine the most suitable directions, shapes, and sizes of the buildings that would be built in Bayburt was carried out. Although the modeling was applied for sample buildings that have specific sizes and shapes and some results were obtained, this modeling can be used for other buildings which have different shapes and the most suitable direction and location designation that can be done. In the solar energy analysis made for the buildings, a year time was divided into four different periods. Related evaluations were made by taking into account that the building should be in shape and orientation which takes the maximum and minimum radiance in the summer and winter. Basic parameters were determined as azimuth angle, the ratio of the building length to its width, and the total periodical radiance that the building takes.

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• MakaleAçık Erişim2013Scopus SJRQ2/r/bayburt/13659
  Energetic and exergetic comparison of air to air and air to water heat pumps according to evaporator conditions

  Çomakli, Kemal; Çakir, Uǧur; Şahin, Erol; Kuş, Ayşegül Çokgez

  This paper presents an experimental energetic and exergetic comparison for a heat pump system that can be run in different modes as air to air and air to water. Components of the heat pump do not change when the running mode changes, except for the condenser. This means that some external and internal effects (like compressor type, pipe lines) that can affect the system performance will be the same for each running mode. The comparison which was made in this study demonstrates which system leads to an efficient conversion and supply of energy and exergy. In the analysis, four balance (mass, energy, entropy and exergy) equations are applied to the system for the two modes. Exergy and energy efficiency values for both systems are given, while exergy destructions in each of the systems are determined and presented. It is seen that the heat pump unit which has the highest COP value is the air to air type (3.45-3.8); second is the air to water type (3.35-3.41). The exergy efficiency of the air to air heat pump (29-32%) is higher than the exergy efficiency of the air to water type heat pump (24.1-25). Ranking of the exergy destruction rates of the two heat pump types from high to low is as follows: air to air and air to water.

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  AtıfScopus5·OpenAlex5

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• MakaleYalnız künye2013Scopus SJRQ1/r/bayburt/12485
  An experimental exergetic comparison of four different heat pump systems working at same conditions: As air to air, air to water, water to water and water to air

  Çakir, Uǧur; Çomakli, Kemal; Çomakli, Ömer; Karsli, Süleyman

  In this study, we designed a multifunctional heat pump system using just one scroll compressor and which can be run in four different modes, namely air to air, air to water, water to water and water to air, in order to make an experimental energetic and exergetic performance comparison. Experimental system consists of two condensers and two evaporators and uses R22 as working fluid. One of the evaporators and condensers uses water and the others use air as heat source/sink. Heating capacities of four heat pump types are equal to each other. It is realized by adjusting the mass flow rate and temperature level of external fluid of condenser. Results show that the heat pump unit which has the maximum COP (coefficient of performance) value is water to air type with 3.94 and followed by water to water type with 3.73, air to air type with 3.54 and air to water type with 3.40. Ranking of four heat pump types with respect to their mean exergy efficiency is as follows; water to air type with 30.23%, air to air type with 30.22%, air to water type with 24.77% and water to water type with 24.01%. Exergy destruction rates of the systems were investigated in this study and the results revealed that the heat pump type which has the maximum exergy destruction is air to air type with 2.93kW. The second highest one is air to water type with 2.84kW. The third highest one is water to air type with 2.64kW and last one is water to water type with 2.55kW. It is understood that the temperature of the evaporator external fluid affects the exergetic efficiency of the system more than the mass flow rate. In contrast to the previous, the dominant parameter which has more important effect on the exergy destruction of the heat pump unit is the mass flow rate of evaporator external fluid.

  AtıfScopus55·WoS46

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• BildiriAçık Erişim2012Scopus SJRQ1/r/bayburt/13967
  The relation of collector and storage tank size in solar heating systems

  Çomakli, Kemal; Çakir, Uǧur; Kaya, Mehmet; Bakirci, Kadir

  The most popular method to benefit from the solar energy is to use solar water heating systems since it is one of the cheapest way to benefit from the solar energy. The investment cost of a solar water heating system is very low, and the maintenance costs are nearly zero. Using the solar energy for solar water heating (SWH) technology has been greatly improved during the past century. A storage tank is used in many solar water heating systems for the conservation of heat energy or hot water for use when some need it. In addition, domestic hot water consumption is strongly variable in many buildings. It depends on the geographical situation, also on the country customs, and of course on the type of building usage. Above all, it depends on the inhabitants' specific lifestyle. For that reason, to provide the hot water for consumption at the desirable temperature whenever inhabitants require it, there must be a good relevance between the collectors and storage tank. In this paper, the optimum sizes of the collectors and the storage tank are determined to design more economic and efficient solar water heating systems. A program has been developed and validated with the experimental study and environmental data. The environmental data were obtained through a whole year of operation for Erzurum, Turkey.

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  AtıfScopus103·WoS87·OpenAlex108

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• BildiriYalnız künye2012Scopus SJRQ1/r/bayburt/12611
  The role of cogeneration systems in sustainability of energy

  Çakir, Uǧur; Çomakli, Kemal; Yüksel, Fikret

  Cogeneration system (CHP) is one of the ways to save the energy and use the energy efficiently. When compared to separate fossil-fired generation of heat and electricity, CHP may result in a consistent energy conservation (usually ranging from 10% to 30%) while the avoided CO 2 emissions are, as a first approximation, similar to the amount of energy saving. In terms of sustainability, one of the primary considerations is energy efficiency. Sustainable energy is considered as a kind of energy which is renewable and continuous, meaning that the use of such energy can potentially be kept up well into the future without causing harmful repercussions for future generations. In this study, environmental benefits and sustainability aspects of cogeneration systems and importance of those systems to the use of sustainable energy are underlined. To support this idea, first we have referred some scientific studies previously made on cogeneration systems and then we have used our own case study. The case study made on gas engined cogeneration system was applied for a hospital to show the sustainability aspects of cogeneration systems.

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  AtıfScopus115·WoS97·OpenAlex135

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