Investigation Of The Effect Of Using Phase Change Materials On Heat Gain At Building Walls With Different Orientations

Meral Özel; Fethi Ahmet Çakmak

Makale detayları

Investigation Of The Effect Of Using Phase Change Materials On Heat Gain At Building Walls With Different Orientations

Yazarlar:

Meral Özel | Fethi Ahmet Çakmak

Yayıncı:

Fırat University

Ana Başlıklar:

Mühendislik

Dergi:

Fırat Üniversitesi Mühendislik Bilimleri Dergisi Vol.35 Issue 1, pp.413-424

Belge Tipi:

Makale

Yayın Tarihi:

3/2023

Belge Dili:

Türkçe

Document ID (Org No.):

2001285881

pISSN:

1308-9072

Anahtar kelimeler:

Özet:

 In this study, cooling loads were investigated numerically with ANSYS Fluent program by using phase change material PCM instead of traditional thermal insulation material on the exterior walls of buildings facing different directions. Analyzes were carried out in two dimensions and depending on time. Considering the summer climatic conditions of the Elazığ province, it is assumed that the buildings outer surface of the building is exposed to changing solar radiation and outdoor temperatures for 24 hours, and the inner surface is in contact with the room air at a constant temperature. For this purpose, five different wall models were considered and firstly, the temperature distributions and cooling loads were calculated along the wall thickness, and then the time lag and decrement factor represented the thermal storage capacities were determined. The results obtained were compared with the existing insulation. As a result, by applying PCM of the same thickness to the wall instead of insulation, external temperature fluctuations for all wall orientations are reduced and its spread to the interior surface is minimized. In addition, it was observed that the heat storage capacity of the wall increased from the point of view of maximum time lag and minimum decrement factor by applying PCM to the wall. It has been seen that the use of phase change material on the outside is more efficient and 2oC lower temperature is obtained on the inner surface compared to the non-insulated wall. Owing to the UDF User-defined function code used in the study, the temperature values in each hour are given as variable boundary conditions.

 In this study, cooling loads were investigated numerically with ANSYS Fluent program by using phase change material PCM instead of traditional thermal insulation material on the exterior walls of buildings facing different directions. Analyzes were carried out in two dimensions and depending on time. Considering the summer climatic conditions of the Elazığ province, it is assumed that the buildings outer surface of the building is exposed to changing solar radiation and outdoor temperatures for 24 hours, and the inner surface is in contact with the room air at a constant temperature. For this purpose, five different wall models were considered and firstly, the temperature distributions and cooling loads were calculated along the wall thickness, and then the time lag and decrement factor represented the thermal storage capacities were determined. The results obtained were compared with the existing insulation. As a result, by applying PCM of the same thickness to the wall instead of insulation, external temperature fluctuations for all wall orientations are reduced and its spread to the interior surface is minimized. In addition, it was observed that the heat storage capacity of the wall increased from the point of view of maximum time lag and minimum decrement factor by applying PCM to the wall. It has been seen that the use of phase change material on the outside is more efficient and 2oC lower temperature is obtained on the inner surface compared to the non-insulated wall. Owing to the UDF User-defined function code used in the study, the temperature values in each hour are given as variable boundary conditions.

 In this study, cooling loads were investigated numerically with ANSYS Fluent program by using phase change material PCM instead of traditional thermal insulation material on the exterior walls of buildings facing different directions. Analyzes were carried out in two dimensions and depending on time. Considering the summer climatic conditions of the Elazığ province, it is assumed that the buildings outer surface of the building is exposed to changing solar radiation and outdoor temperatures for 24 hours, and the inner surface is in contact with the room air at a constant temperature. For this purpose, five different wall models were considered and firstly, the temperature distributions and cooling loads were calculated along the wall thickness, and then the time lag and decrement factor represented the thermal storage capacities were determined. The results obtained were compared with the existing insulation. As a result, by applying PCM of the same thickness to the wall instead of insulation, external temperature fluctuations for all wall orientations are reduced and its spread to the interior surface is minimized. In addition, it was observed that the heat storage capacity of the wall increased from the point of view of maximum time lag and minimum decrement factor by applying PCM to the wall. It has been seen that the use of phase change material on the outside is more efficient and 2oC lower temperature is obtained on the inner surface compared to the non-insulated wall. Owing to the UDF User-defined function code used in the study, the temperature values in each hour are given as variable boundary conditions.

 Bu çalışmada, farklı yönlere bakan bina dış duvarlarında geleneksel ısı yalıtım malzemesi yerine faz değiştiren malzeme FDM kullanılarak soğutma yükleri ANSYS Fluent programı ile nümerik olarak araştırılmıştır. Analizler iki boyutlu ve zamana bağlı olarak gerçekleştirilmiştir. Elazığ ilinin yaz iklim şartları göz önünde bulundurularak bina dış yüzeyinin 24 saat boyunca değişen güneş ışınımı ve dış ortam sıcaklıklarına maruz bırakıldığı iç yüzeyinin ise sabit sıcaklıkta oda havasıyla temasta olduğu kabul edilmiştir. Bu amaçla 5 farklı duvar modeli belirlenerek ilk olarak duvar kalınlığı boyunca sıcaklık dağılımları ve soğutma yükleri hesaplanmış ve daha sonra ise ısıl depolama kapasitelerini temsil eden faz kayması ve sönüm oranları tespit edilmiştir. Elde edilen sonuçlar mevcut yalıtım ile kıyaslanmıştır. Sonuç olarak, duvara yalıtım yerine aynı kalınlıkta FDM uygulanarak tüm duvar yönlendirmeleri için dış sıcaklık dalgalanmaları sönümlenip iç yüzey yayılımının en aza indirilmesi sağlanmıştır. Ayrıca duvara FDM uygulanarak maksimum faz kayması ve minimum sönüm oranı açısından duvarın ısı depolama kapasitesinin de arttığı görülmüştür. Faz değiştiren malzemenin dışta kullanılmasının daha verimli olduğu görülmüş ve yalıtımsız duvara göre iç yüzeyde 2oC daha düşük sıcaklık elde edilmiştir. Çalışmada kullanılan UDF User-defined function kodu sayesinde her bir saatteki sıcaklık değerleri değişken sınır şartı olarak verilmiştir.

Makale detayları

Investigation Of The Effect Of Using Phase Change Materials On Heat Gain At Building Walls With Different Orientations

Yazarlar:

Meral Özel | Fethi Ahmet Çakmak

Yayıncı:

Fırat University

Ana Başlıklar:

Mühendislik

Dergi:

Fırat Üniversitesi Mühendislik Bilimleri Dergisi Vol.35 Issue 1, pp.413-424

Belge Tipi:

Makale

Yayın Tarihi:

3/2023

Belge Dili:

Türkçe

Document ID (Org No.):

2001285881

pISSN:

1308-9072

Phase change material (PCM)

different wall orientations

cooling loads

time lag

decrement factor.

Faz değiştiren malzeme (FDM)

farklı duvar yönlendirmeleri

soğutma yükü

faz kayması ve sönüm oranı

Sayı

Makale detayları

Yazarlar: Meral Özel | Fethi Ahmet Çakmak

Yayıncı: Fırat University

Ana Başlıklar: Mühendislik

Dergi: Fırat Üniversitesi Mühendislik Bilimleri Dergisi Vol.35 Issue 1, pp.413-424

Belge Tipi: Makale

Yayın Tarihi: 3/2023

Belge Dili: Türkçe

Document ID (Org No.): 2001285881

pISSN: 1308-9072

Sayı

Yazarlar:

Meral Özel | Fethi Ahmet Çakmak

Yayıncı:

Fırat University

Ana Başlıklar:

Mühendislik

Dergi:

Fırat Üniversitesi Mühendislik Bilimleri Dergisi Vol.35 Issue 1, pp.413-424

Belge Tipi:

Makale

Yayın Tarihi:

3/2023

Belge Dili:

Türkçe

Document ID (Org No.):

2001285881

pISSN:

1308-9072