Doğal havalandırmalı seralarda hesaplamalı akışkanlar dinamiği tekniği kullanılarak bazı iklim parametrelerinin belirlenmesi

Year 2015, Volume: 28 Issue: 2, 71 - 76, 23.12.2015

Ahmet Tezcan Kenan Buyuktas

Abstract

Çalışmanın amacı, Doğu-Batı yönünde yöneylenmiş 90° pencere açıklığına, bitkili ve bitkisiz ortamlar gibi farklı yetiştirme koşullarına sahip doğal havalandırmalı, beşik çatılı seralarda ölçülen iç hava sıcaklığı ve bağıl nem değerleri ile Hesaplamalı Akışkanlar Dinamiği (HAD) tekniği ile simüle edilen değerlerle karşılaştırmaktır. Çalışmada, Batı Akdeniz tarımsal Araştırma Enstitüsü’ndeki beşik çatılı tekil seralar materyal olarak seçilmiştir. Çalışma alanı 36º 52' K enlemi ve 30º 50' D boylamında yer almaktadır. Materyal olarak seçilen seralarda, ölçülen değerler farklı noktalara yerleştirilmiş hava sıcaklığı ve bağıl nem ölçerler kullanılarak 08:00-18:00 arasında dakikalık olarak kaydedilmiştir. Ancak bu değerler veri sayısını azaltmak için hesaplamalarda 2 saatlik ortalamalar şeklinde kullanılmıştır. Solidworks analiz yazılımı materyal olarak seçilen seraların HAD simülasyonları için kullanılmıştır. Sera içindeki hava sıcaklığı ve bağıl nem değerleri dış ortam sınır koşulları ve seranın yapısal ve fiziksel özelliklerine göre simüle edilmiştir. Daha sonra, ölçülen değerler simüle edilen değerlerle karşılaştırılmış ve bu değerlerin uyum düzeyleri belirlenmiştir. Sonuç olarak, bitkili serada ölçülen ve simüle edilen hava sıcaklığı ve bağıl nem değerlerinin hata oranları sırasıyla % 4.9 ve % 0.0 olarak bulunmuştur. Ayrıca, aynı değerler bitkisiz serada sırasıyla % 0.0 ve % 5.2 olarak bulunmuştur. Çalışma göstermiştir ki, HAD doğal havalandırmalı seralarda sera içi iklim faktörlerinin belirlenmesinde güçlü bir araç olarak kullanılabilir.

Keywords

Hava sıcaklığı, Analiz, HAD, Sera, Bağıl nem

Determining of some climate parameters using computational fluid dynamic technique in naturally ventilated greenhouses

Abstract

Aim of study was to compare the measured inner air temperature and relative humidity values with the simulated values determined with Computational Fluid Dynamics (CFD) technique in the naturally ventilated gable-roofed single glasshouses located East-West direction, having 90° window span and different growing conditions such as plant and without plants. In study, the gable roofed single glasshouses in West Mediterranean Agricultural Research Institute were chosen as material. Study area is located at the latitude of 36º 52' N and longitude of 30º 50' E. In the greenhouses selected as material, measured values were recorded every minute from 8 a.m. to 18 p.m. by using the relative humidity and air temperature meters placed in different locations. However, these values were used as average of 2 hours in calculations to reduce number of data. The Solid Works analysis software was used for CFD simulations of the greenhouses selected as material. The air temperature and relative humidity values inside the greenhouse were simulated depending on the outside ambient conditions and structural and physical properties of greenhouse. Then, the measured values were compared with the simulated values and compliance levels of these values were determined. In conclusion, the error rates of measured and simulated air temperature and relative humidity values in the greenhouse with plant were found as 4.9% and 0.0%, respectively. Additionally, the same values in the greenhouse without plant were also found as 0.0% and 5.2%, respectively. The study showed that the CFD may be used as a powerful tool for determining inner climatic factors in naturally ventilated greenhouses.

Keywords

Air temperature, Analysis, CFD, Greenhouse, Relative humidity

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