Year-round performance assessment of a ground source heat pump with multiple energy piles

The year-round performance of a ground source heat pump (GSHP) with multiple energy piles (EPs) is investigated in this study based on a 3D transient heat transfer model. The GSHP heating and cooling capabilities are simulated and assessed according to thermal energy demands of an air conditioned domestic building, its coefficients of performance (COPs) obtained from numerical analyses and experimental tests are compared and the largest difference between them is less than 8%. The maximum heating and cooling COPs of the GSHP are 3.63 and 4.73 respectively in the first year operation period, and the soil final temperature is lower than its initial temperature, therefore the soil is not capable of recovering by itself due to the building unbalanced heating and cooling loads. Finally, the effects of the soil thermal properties on its temperature and the GSHP COPs are investigated and compared between the first year and tenth year operations, and it is found that the soil with low volumetric heat capacity and high thermal conductivity could achieve a quick temperature recovery

Assessment Of Gas And Coal Outbursts In Turkish Hard Coal Enterprise Collieries And Investigation Of Factors Influencing The Outbursts

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2013Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2013Bu çalışmada, Zonguldak Taşkömürü Havzası’nda 1969 – 2012 yılları arasında meydana gelen ani gaz ve kömür püskürmesi olayları (derinlik, damar kalınlığı ve eğimi, atılan kömür miktarı ve açığa çıkan gaz hacmi vb.) istatistiksel olarak değerlendirilmiştir. Daha sonra olayların meydana gelişinde rol oynayan etkenlerden; kömürün yapısal özellikleri (kömürleşme derecesi, kömürün gevrekliği, vb.), kömür damarının içerdiği gaz miktarı, kömürdeki gazın desorpsiyon hızı ve kaya basıncı araştırılarak ani püskürmeye eğilimli zonların önceden belirlenmesi amaçlanmıştır. Bu faktörlerin araştırılması için 7 farklı kömür damarından 19 adet numune alınmıştır. Yapılan deneysel çalışmalarda kömür damarlarının gaz içerikleri, dayanımları, kömürdeki gazın desorbe olma hızı ile kaya basınçları belirlenmiştir. Deneyler sonucu kömür damarları, ani gaz ve kömür püskürmesi olaylarına eğilimleri bakımından sınıflandırılmıştır.Bu çalışmada, Zonguldak Taşkömürü Havzası’nda 1969 – 2012 yılları arasında meydana gelen ani gaz ve kömür püskürmesi olayları (derinlik, damar kalınlığı ve eğimi, atılan kömür miktarı ve açığa çıkan gaz hacmi vb.) istatistiksel olarak değerlendirilmiştir. Daha sonra olayların meydana gelişinde rol oynayan etkenlerden; kömürün yapısal özellikleri (kömürleşme derecesi, kömürün gevrekliği, vb.), kömür damarının içerdiği gaz miktarı, kömürdeki gazın desorpsiyon hızı ve kaya basıncı araştırılarak ani püskürmeye eğilimli zonların önceden belirlenmesi amaçlanmıştır. Bu faktörlerin araştırılması için 7 farklı kömür damarından 19 adet numune alınmıştır. Yapılan deneysel çalışmalarda kömür damarlarının gaz içerikleri, dayanımları, kömürdeki gazın desorbe olma hızı ile kaya basınçları belirlenmiştir. Deneyler sonucu kömür damarları, ani gaz ve kömür püskürmesi olaylarına eğilimleri bakımından sınıflandırılmıştır.Yüksek LisansM.Sc

Classification of Coal Seams for Coal and Gas Outburst Proneness in the Zonguldak Coal Basın, Turkey

Coal and gas outbursts can be defined as a sudden release of coal and rock accompanied by large quantities of gas into the working face or other mine workings. It has been a major geological hazard to underground coal mining for over 150 years, and continues to cause serious problems all over the world. The outburst events have appeared rarely in metal mines and have generally occurred in salt and coal mines especially bituminous coal mines. Coal outbursts have occurred in at least 18 nations including Turkey. The most important factors that influence the occurrence of outbursts are gassiness of the coal seam and the desorption rate of the gas in the seam and or part of the coal seam. It is necessary to investigate these factors separately to predict the outburst prone zones. The aim of this study is to determine the outburst prone zones in the Zonguldak Coal Basin. In order to determine the outburst proneness of the coal seams, coal samples were taken from Kozlu and Karadon Collieries. 19 coal samples were taken from underground working areas, from 7 different coal seams, at different depths and with variable borehole lengths. Gas content of the coal seams was measured with US Bureau of Mines (USBM) Direct Method. Desorption rate of the gas in coal was investigated and a threshold limit determined for the study area. According to the experimental results, the coal seams have been classified with regard to outburst prone zones

Gas Desorption Rate of Coal Seams in Zonguldak Coal Basic as an Indicator of Outburst Proneness

Outburst is a significant hazard in underground coal mining and may be expressed as a violent ejection of coal and gas from the mining face. Greatest risk of outburst is during initial intersection of an unmined coal seam and during development mining of the coal seam in close proximity to geological disturbances. Outburst events have been reported during underground mining operations in over 18 countries, including Turkey, for over 150 years. In the Zonguldak Coal Basin, located on the Black Sea coast of North West Turkey, 90 outbursts were recorded over 44 years, between 1969 and 2013, resulting in 374 fatalities. To protect the mine workings from the outburst hazard, the outburst indicators, ΔP0-60, ΔPexpress and the KT index, have been investigated to evaluate potential application to predict outburst prone areas. The study of 166 coal samples collected from the three (3) coal seams, Acilik, Sulu and Cay seams, mined at Kozlu and Karadon collieries in the Zonguldak Coal Basin, found the results of ΔP0-60, ΔPexpress and the KT index ranged between 2 to 26 mmHg, 0.16 to 0.76 bar, and 0.57 to 0.79 respectively. These results were compared with threshold limit values reported in previous studies to identify areas of potential increased outburst risk

An Investigation of the Coal Seam Gas Content and Compositon in Soma Coal Basin, Turkey

The Miocene Soma Basin in Turkey is estimated to contain at least one billion tons of lignite and about half of this reserve is present at depths greater than 600 m. In the Soma Basin, Turkish Coal Enterprises (TKI) has conducted open cut coal mining and underground coal mining activities for several decades in the Northern and Central part of the basin. It is known from the mining operations that the Soma coal basin has considerably gassy coal seams, but until now there isn’t any sufficient scientific and technical research about gas content and composition of coal seams in the basin. Recently, coal exploration activities have been extended to the Southern part of the basin by means of exploratory drilling. In this context, 49 coal core samples were collected and were analysed in terms of gas content and composition. The gas content measurements indicate that as much as 4.2 m3/t coal is present in the coal recovered from 1010.50 to 1010.90 m below the surface. The composition of the gas is dominantly methane with more than 80 %. Considering the chemical composition of the gas and gas indices, the source of the coal gas is biogenic probably generated by bacteria that are introduced to the coal seam by fresh water following mainly the normal faults bordering the graben structure. The possibility of coalbed methane potential of the basin is also investigated with regard to preliminary gas content data