Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2015Scopus SJRQ1Using 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.
AtıfScopus93WoS77OpenAlex95
İncele - Kitap BölümüYalnız künye2014A 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.
- MakaleAçık Erişim2013Scopus SJRQ2Energetic 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.
AtıfScopus5OpenAlex5İncele