Jeotermal ısı pompasıyla ısıtılan bir seranın termoekonomik analizi
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Dosyalar
Tarih
2019
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Bursa Teknik Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Dünyadaki hızlı nüfus artışı, tarım alanlarının giderek azalması, tarımda ileri teknolojik gelişmelere ayak uydurulamaması ve ürünlerden elde edilen verimin düşmesi ülkelerin hemen hemen hepsinde gıda gereksinimlerinin istenilen düzeyde karşılanamaması sorununa yol açmıştır. Bu sorun üreticileri mevsim dışı üretim yapma yollarına itmiştir. Seralar, doğal iklim koşullarının bitki üretimi için uygun olmadığı yerlerde ya da mevsimlerde üretim yapmak için özel olarak oluşturulan yapılardır. Seracılığın ilk örnekleri İtalya'da Romalılar döneminde sebze yetiştiriciliği olarak görülmektedir. Günümüzde seraların çoğunda sadece kış aylarında ya da gece bitkileri dondan korumak amaçlı ısıtma yapılmaktadır. Ancak sürekli ısıtmanın yapılmaması elde edilen verimi düşürmektedir. Seraların büyük çoğunluğunda doğal gaz, petrol gibi fosil yakıtların kullanıldığı ısıtma sistemleri yaygındır. Fosil yakıtların giderek azalması, çevreye olumsuz etkileri gibi nedenler üreticileri alternatif enerji çeşitlerine yönlendirmiştir. Yenilenbilir enerji kaynaklarından olan jeotermal enerji günümüzde seracılıkta kullanılmaktadır. Bu çalışmada Bursa ili Orhangazi ilçesi Keramet bölgesinde yer alan bir jeotermal kaynak esas alınmıştır. Kaynak sıcaklığının düşük olması ve kaynağın tarım arazisi üzerinde bulunması nedeniyle sera ısıtmasında kullanılması olanakları değerlendirilmiştir. Kaynakta yaklaşık 31 °C sıcaklık ve 53,3 L/s debide jeotermal su mevcuttur. Kaynak sıcaklığının düşük olması nedeniyle jeotermal kaynak jeotermal ısı pompasıyla (GSHP) desteklenmiştir. Bursa ili iklim koşullarında 1000 m2 (1 dönüm) taban alanına sahip, polietilen (PE) plastik örtülü temsili bir çiçek serası hesaplamalarda baz alınmıştır. Isı pompasıyla desteklenen jeotermal enerjinin temsili bir sera ısıtmasında kullanılmasına ilişkin temel tasarım özellikleri incelenmiştir. Seranın bölge iklim koşullarına göre ısı gereksinimi belirlenmiş ve bu gereksinimi karşılayacak bir ısı pompası seçilmiştir. Sistemde yer alan diğer ekipmanların tasarım değişkenleri belirlenmiştir. Meteorolojiden alınan verilere göre Bursa için dış ortam tasarım sıcaklığı -6 °C iken çiçek yetiştiriciliğinde iç tasarım sıcaklığı 15 °C kabul edilmiştir. Bu sıcaklık koşullarında PE plastik seranın ısı gereksinimi yaklaşık 236,5 kW olarak belirlenmiştir. Yapılan hesaplamarla birlikte klasik ısıtma sistemlerine sahip bir seranın ilk yatırım maliyetleriyle jeotermal ısı pompası sistemine sahip bir seranın ilk yatırım maliyetleri karşılaştırılarak ekonomik analiz yapılmıştır. Daha sonra her iki sistemin enerji tüketimleri BIN yöntemiyle hesaplanmış ve enerji maliyetleri belirlenmiştir. Isı pompalı sistemin yakıttan elde edilen tasarrufu dikkate alınarak sistemin ömürlük kazanım maliyeti (LCSA) hesaplanmıştır. Bu maliyet hesabına göre sistemin kendini geri ödeme süresi 18 yıl olarak bulunmuştur. Alternatif bir yaklaşımla sera ısıtma sistemi hibrit bir sistem olarak tasarlandığında geri ödemesi süresi 10 yıla düşmektedir. Burada hibrit sistem olarak dış ortam sıcaklığı 1,5 °C'nin altına düşünceye kadar ısı pompası sistemi daha düşük sıcaklıklarda ise doğal gaz yakıtlı kazan kullanılacaktır.
The rapid population growth in the world, the decrease in agricultural areas, the inability to keep up with the advanced technological developments in agriculture and the decrease in the yield obtained from the products have led to the problem of not meeting the food requirements in almost all countries. This problem has led the producer to off-season production. Greenhouses are structures that are specially created for production in places or seasons where natural climatic conditions are not suitable for plant production. The first examples of greenhouse cultivation are seen in Italy as vegetable growing in the Roman period. Nowadays, most of the greenhouses are heated only in winter or at night to protect the plants from frost. However, the lack of continuous heating reduces the yield. In the majority of greenhouses, heating systems using fossil fuels such as natural gas and oil are common. The reasons such as the decrease in fossil fuels and the negative effects on the environment led the producers to employ alternative energy technology. Geothermal energy, which is one of the renewable energy sources, is used in greenhouse cultivation today. In this study, a geothermal resource located in the Keramet region of Orhangazi district of Bursa was taken into consideration. Since the resource temperature is low and the resource is located on agricultural land, the possibilities for using it in greenhouse heating have been evaluated. The source contains geothermal water at a temperature of about 31 ° C and a flow rate of 53.3 L / s. Due to the low well temperature, the geothermal source was supported by a geothermal heat pump (GSHP). A representative flower greenhouse of 1000 square meters (1 decare) with a polyethylene (PE) cover under climate conditions in Bursa is based on the calculations. The basic design features of the use of geothermal energy supported by heat pump in a representative greenhouse heating are examined. The heat requirement of the greenhouse was determined according to the climatic conditions of the region and a heat pump was selected to meet this requirement. The design variables of the other equipment in the system were determined. According to the data obtained from the meteorology, the outdoor design temperature was accepted as -6 ° C and the interior design temperature in flower cultivation as 15 ° C. Under those temperature conditions, the heat requirement of PE plastic greenhouse was determined as approximately 236,5 kW. With the calculations, the first investment costs of a greenhouse with conventional heating methods and the first investment costs of a greenhouse with a geothermal heat pump were compared. Then, energy consumption of both systems was calculated by BIN method and energy costs were determined. Taking into consideration the fuel savings of the heat pump system, the life cycle saving of the system (LCSA) was calculated. According to this cost calculation, the selfrepayment period of the system was found to be 18 years. When the greenhouse heating system is designed as a hybrid system with an alternative approach, the payback period is reduced to 10 years. As a hybrid system, natural gas fuel boiler will be used if the heat pump system is at lower temperatures until the outdoor temperature falls below 1.5 ° C.
The rapid population growth in the world, the decrease in agricultural areas, the inability to keep up with the advanced technological developments in agriculture and the decrease in the yield obtained from the products have led to the problem of not meeting the food requirements in almost all countries. This problem has led the producer to off-season production. Greenhouses are structures that are specially created for production in places or seasons where natural climatic conditions are not suitable for plant production. The first examples of greenhouse cultivation are seen in Italy as vegetable growing in the Roman period. Nowadays, most of the greenhouses are heated only in winter or at night to protect the plants from frost. However, the lack of continuous heating reduces the yield. In the majority of greenhouses, heating systems using fossil fuels such as natural gas and oil are common. The reasons such as the decrease in fossil fuels and the negative effects on the environment led the producers to employ alternative energy technology. Geothermal energy, which is one of the renewable energy sources, is used in greenhouse cultivation today. In this study, a geothermal resource located in the Keramet region of Orhangazi district of Bursa was taken into consideration. Since the resource temperature is low and the resource is located on agricultural land, the possibilities for using it in greenhouse heating have been evaluated. The source contains geothermal water at a temperature of about 31 ° C and a flow rate of 53.3 L / s. Due to the low well temperature, the geothermal source was supported by a geothermal heat pump (GSHP). A representative flower greenhouse of 1000 square meters (1 decare) with a polyethylene (PE) cover under climate conditions in Bursa is based on the calculations. The basic design features of the use of geothermal energy supported by heat pump in a representative greenhouse heating are examined. The heat requirement of the greenhouse was determined according to the climatic conditions of the region and a heat pump was selected to meet this requirement. The design variables of the other equipment in the system were determined. According to the data obtained from the meteorology, the outdoor design temperature was accepted as -6 ° C and the interior design temperature in flower cultivation as 15 ° C. Under those temperature conditions, the heat requirement of PE plastic greenhouse was determined as approximately 236,5 kW. With the calculations, the first investment costs of a greenhouse with conventional heating methods and the first investment costs of a greenhouse with a geothermal heat pump were compared. Then, energy consumption of both systems was calculated by BIN method and energy costs were determined. Taking into consideration the fuel savings of the heat pump system, the life cycle saving of the system (LCSA) was calculated. According to this cost calculation, the selfrepayment period of the system was found to be 18 years. When the greenhouse heating system is designed as a hybrid system with an alternative approach, the payback period is reduced to 10 years. As a hybrid system, natural gas fuel boiler will be used if the heat pump system is at lower temperatures until the outdoor temperature falls below 1.5 ° C.
Açıklama
Anahtar Kelimeler
Makine Mühendisliği, Mechanical Engineering
