Study of combined structure of geo-heat exchangers

A geo heat exchanger (GHE) utilises a pipe configuration, buried in the ground, to harvest geothermal energy at shallow depths. A GHE could be used in heating and cooling systems as the ground temperature is normally higher than the average air temperature in winter and lower in summer. This difference in the temperature can be utilised to improve the efficiency of air conditioning systems (in summer) and heat pumps (in winter). Two basic arrangements of GHEs are commonly used: vertical and horizontal. Vertical GHEs, which are particularly suitable for confined spaces, generally have a better performance due to stable soil temperature deep down in comparison with the horizontal arrangement. However, their installation cost is relatively high. Meanwhile, the efficiency of horizontal GHEs may benefit from ambient temperature fluctuations and lower installation costs due to the shallow depth of burying of GHEs. However, this arrangement requires a large land area for installation, which may substantially increase the capital cost. In addition, GHEs’ performances, especially for vertical ones, may suffer deterioration with an increase in the operation times due to heat or (coldness) accumulation in the soil. In this study, a combined horizontal-vertical GHE arrangement is proposed to synergy the benefits of the two configurations and negate their disadvantages. The overall aim of this project is to understand the thermo-dynamic performance of GHEs (including the horizontal, vertical and combined GHE) under various loads and weather/soil conditions, in order to optimise their designs and operations by developing validated computational models of the heat exchangers. Mathematical models for both horizontal and vertical GHEs have been developed which take into account the fluctuations in soil temperature during seasonal changes. The newly developed models are different from the existing models most of which overlooked the seasonal changes in soil temperature. In the new models, the seasonal changes in soil temperature, which are affected by the thermal interaction between the ground and the atmosphere, are incorporated with a help of an internal source term approach. The values of the internal source term depend on geographic locations and soil depths. The finite difference method is used to obtain the numerical solution of the proposed GHE models. The models are validated using experimental data obtained from custom-built rigs. The simulation results show that the new approach, which takes into account the effect of seasonal periodic soil temperature fluctuations on the performance of the GHE, agrees well with experimental data. The validated models are then used to conduct a sensitivity analysis with the aim of investigation of the effect of design parameters on the performance of the horizontal, vertical and combined GHE. Outcomes of two case studies are presented to demonstrate the benefits of the combined GHE. The first study was conducted to assist with the operation of cooling systems of Terminal 1 building of the Adelaide airport. The second study analysed the efficiency of the combined GHE for an air conditioning system (heat pump) for twenty units of residential houses. The thesis has been organised into eight chapters. The structure of the thesis is summarised as follows: Chapter 1-Introduction: This chapter introduces background, gaps identified in GHEs research area, aims and objectives of the study, contributions to the field, and scope and limitations. Chapter 2-Literature review: This chapter provides a brief description of ground source air conditioning systems (heat pumps), soil thermal characteristics, the review of GHE models and operation modes, and thermodynamic analysis to account the energy savings of the ground source air conditioning systems (heat pumps). The chapter concludes with a summary of the literature review. Chapter 3-Seasonal soil temperature changes: The chapter elaborates the method used in order to determine the profile of soil temperature at various depths for a specific day in a year. In addition, it summarises a new approach to model the soil temperature fluctuations during seasonal changes on the GHE’s performance. In which the seasonal soil temperature changes are expressed as an internal source term and incorporated into the GHE model. Chapter 4-Horizontal GHE: This chapter presents the developed mathematical model for the horizontal GHE and outcomes of the comparison with experimental data obtained with a reduced scale GHE custom-built rig. It is followed by sensitivity analysis to investigate the technical parameters affecting the performance of the GHE. Chapter 5-Vertical GHE: The mathematical model that predicts the performance of the vertical GHE is presented in this chapter. An experimental study utilising a scale down experimental rig has been conducted to validate the model. Then, the sensitivity analysis is performed using the validated model to investigate the effect of some design and operational parameters on the vertical GHE’s performance including borehole thermal conductivity, borehole depth, fluid flow rate, and types of carries fluids. In addition, the dynamic performance of the GHE under continuous and intermittent loads is also investigated. Chapter 6-Combined horizontal-vertical GHE: This chapter analyses the performance of a combined horizontal-vertical GHE based on the two separate validated models. Chapter 7-Case studies: This chapter demonstrates the potential applications of the combined GHEs to assist in the operation of air conditioning systems. These two studies are focused on the analysis of the combined GHE for the Terminal 1 building, Adelaide airport and twenty units of residential buildings. Chapter 8-Conclusion: This chapter summarises the result of this thesis and discusses the future work.Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 201

Experimental study the effect of diesel engine performance fuelled by waste tire oil- dexlite blends

It well known that tire as a waste from vihicles susch as passengger car, truck and trailller. Indonesia country has enough potensial of tire waste, it was produced of about 11 millions ton per years. This phenomena could be serious environmental problem because tire waste was difficult dissolve by environment. It is needs to solve this issue by convert the waste tire to oil fuels. The main focus of this research to evaluate the performance of diesel engine fuelled by waste tire oil-dexlite blends. The physicochemical properties such as viscosity, density, calorific value and cetane number the waste tire fuel and its blends with dexlite were analysed. The experimental methode to determine engine performance by using the CI engine with variation of speed from 1500 rpm to 2100 rpm and waste tire-dexlite blends ratios at 10% (WTO-10), 20% (WTO-20) and 30% (WTO-30) of waste tire oil (WTO) and dexlite were utilized as a fuels. The CI engine with variation of speed from 1500 rpm to 2100 rpm was selected in order to determine the engine performance. The experimental results showed that the blending of waste tire oil with dexlite from 10% to 30% can operate with CI engine without any engine modifications. The results of this study revealed that maximum power and SFC were found to be 2.3 kW and 0.48 kg/kWh, respectively. Moreover, at the engine speed of 1900 rpm and a fuel blend of WTO-10 were found that to be optimal values of power and thermal efficiency which is similarly by using dexlite as fuel

PERANCANGAN ICE COOL BOX MENGGUNAKAN BAHAN COMPOSITE (CBC) PADA KAPAL IKAN LAPIS FIBER 2 GT (GROSS TONNAGE) DALAM MASA KETAHANAN PANGAN DI MASA PANDEMI

Entering the economic era of free competition, various fishing technology supports have increased, but there are difficulties in terms of the availability of fish storage media in the long term. Products circulating today are not able to last long and are easily damaged. The problem that occurs is that the storage media does not have long durability against age, impact, maintenance and ease of repair. The composite material application applies the hand lay up method. The work process is carried out in stages starting from making patterns, molds to finished products. The material used consists of thermosetting resin, supported by reinforcing fiber consisting of E-glass fiber and organic ramie fiber. The combination of the two is called a hybrid material. The stages of this process are carried out efficiently and carefully until the final target is met for a quality Ice cool box product. Ice cool box composite as a direct application of campus research results so that it can be used for the needs of Acehnese fishermen

Perancangan Mesin Pemberi Pakan Otomatis Berbasis Iot (Internet of Things) Untuk Budidaya Ikan Sebagai Solusi Keamanan Pangan Dan Pemanfaatan Energi Berkelanjutan

Budidaya perikanan berperan penting dalam memperkuat ketahanan pangan nasional. Namun, tantangan seperti pengelolaan jadwal pemberian pakan yang teratur dan efisien masih dihadapi oleh pelaku budidaya ikan di Aceh. Dalam konteks ini, sebuah solusi diusulkan melalui perancangan mesin pemberi pakan otomatis berbasis IoT. Mesin ini memungkinkan pengawasan dan pengaturan jarak jauh terhadap pemberian pakan, yang tidak hanya mengurangi intervensi manusia tetapi juga membantu meminimalkan pemborosan pakan dan memastikan pemberian pakan yang tepat waktu. Dengan tambahan panel surya, mesin ini mampu menghasilkan energi sendiri, mendukung pemanfaatan energi terbarukan. Solusi ini memanfaatkan model manufaktur efisien dan mampu mengatasi kendala pertumbuhan ikan yang terganggu akibat pengelolaan pakan yang tidak teratur. Selain manfaat langsung bagi hasil panen ikan, produk ini juga dapat meningkatkan pendapatan nelayan mitra. Melalui langkah-langkah seperti pengajuan hak kekayaan intelektual dan pemantauan oleh tim pengusul, diharapkan produk ini dapat berkontribusi pada ketahanan pangan dan berkelanjutan di Aceh.

GAMBAR KARAKTERISTIK PENDERITA TBC YANG DROP OUT DI BP 4 KABUPATEN KEBUMEN TAHUN 2004

Jumlah penderita TBC yang di obati di BP 4 Kabupaten Kebumen tahun 2004 tercatat 903 penderita.jumlah penderita yang sembuh 23,37% jumlah penderita dengan kategori pengobatan lengkap 44,30%, gagal 1,44%drop out 27,68%, pindah 2,66%, meninggal 0,55% Dengan masih tingginya angka kejadian drop out tersebut maka tujuan penelitian ini adalah mengetahui gambaran karakteristik TBC yang drop out, perilaku dan juga mengetahui gambaran keterjangkauan jarak, kemampuan membayar, ada tidaknya Pengawas Menelan Obat (PMO), dan kualitas pelayanan kesehatan. Metode penelitian ini adalah deskriptif dengan pendekatan studi cross sectional. Populasi penelitian ini adlah penderita TBC yang mengalami simpling. Data yang dikumpulkan yaitu data primer dar wawacara dengan responden dan data sekunder yang ada di BP 4 Kabupaten tahun 2004, kemudian dianalisis dengan analisis univariat. Hasil penelitian ini adalh kelompok umur < 14 tahun 80% pada fase awal, jenis kelamin laki-laki mengelami fase linjutan 62,4% pendidikan tidak tamat SD mengalami fase lanjutan 58,1%, pekerjaan sebagai petani mengalamidrop outfase lanjutan. Kesimpulan penelitian ini adalah karakteristik penderita TBC; umur, sex, pendidikan, pekerjaan, pegetahuan, sikap, praktik keterjankuan jarak, kemamuan membayar, ada/tidaknya PMO, kualitas pelayanan kesehatan mempuyai gambaran yang bervariasi terhadap penderita TBC yang mengalami di BP 4 Kebumen tahun 200 Kebumen Regency, on 2004 Kata Kunci: TBC,drop out, ketidakteratura

Modeling of Underground Heat Exchanger for Heat Pump and Air Conditioning Systems

Air conditioning and heat pump systems can use the ground as a medium to dump or absorb heat energy to increase efficiencies. As compared to the air, the ground has lower temperature in the summer and higher in the winter. In this research, the vertical U tube underground heat exchanger that can be used to harvest geothermal energy, has been modeled by using two dimensional finite difference methods. The model is not only able to estimate the water temperatures out of vertical U tube underground heat exchanger, but also capable of calculating the temperature profile change of surrounding soil under various water entering heat exchanger and weather conditions. The heat transfer process between the underground heat exchanger and soil has been investigated and profiles of soil and water temperatures are presented

Mathematical Modelling and Operational Analysis of Combined Vertical–Horizontal Heat Exchanger for Shallow Geothermal Energy Application in Cooling Mode

Geothermal heat exchangers (GHEs) represent a buried pipe system, which can be utilised to harness renewable thermal energy stored in the ground to improve the efficiency of heating and cooling systems. Two basic arrangements of GHEs have been widely used: vertical and horizontal. Vertical GHEs generally have a better performance in comparison with the horizontal arrangement, and these systems are particularly suitable for confined spaces. Nevertheless, the main technical challenge associated with GHEs, for either the vertical or the horizontal arrangement, is the performance deterioration associated with an increase in the operation times during summer or winter seasons. In this paper, a combined horizontal-vertical GHE arrangement is proposed to address the current challenges. The combined GHE arrangement can be operated in five different modes, corresponding to different thermal loading conditions. These five operation modes of the combined GHE are analysed based on the transient finite difference models previously developed for the horizontal and vertical arrangements. The simulation results reveal that for the single operation mode (horizontal or vertical only), the vertical GHE performs better than the horizontal GHE due to relatively stable ground temperature deep down. While, for the combined operation mode, the series operations (horizontal to vertical or vertical to horizontal) of the GHE are superior to the split mode. It is found that the effect of the fluid mass flow rate ratio is trivial on the heat dissipation of the split mode GHE. The highest heat transfer rate in the split flow operational mode is rendered by the ratio of the mass flow rate of 40% horizontal and 60% vertical. In addition, the climate condition has more effect on GHE&rsquo;s performance and the increase of the fluid flow rate it can enhance the amount of energy released by the GHE

PEMANFAATAN LOKASI TAMBAK KAWASAN ALUE NAGA ACEH BESAR UNTUK PENGEMBANGAN BUDIDAYA RUMPUT LAUT JENIS GLACILARIA MENGGUNAKAN FLOATING HOUSE METHOD DALAM MENDUKUNG KETAHANAN PANGAN

Aceh Province is an area surrounded by coasts which has great potential to develop marine product cultivation, one of which is seaweed. In line with the goal of the central government in 2018 stating its support for increaseing seaweed cultivation in Aceh Province. Meanwhile, the Ministry of Maritime Affairs and Fisheries' Directorate General of Cultivation stated that so far the seaweed industry and cultivation are still constrained by transportation problems for marketing. Based on the results of research in a number of regions in Indonesia, it is explained that the coastal area of Aceh is an area that has very good potential for the seaweed cultivation. This study focuses on the Glacilaria sp seaweed cultivation due to its easiness to grow in community ponds. The drawback of this pond cultication method is the existence of predators that eat seaweed and the pond bottom mud that pollutes the seaweed. The application of floating house technology for glacilaria seaweed culture is seen as a solution for aforemention problems. This technology protects the seaweed from predators and the contamination of the seawee from mud pond. The proposed sea seaweed cultivation method is anticipated to offer better income and improve the quality of life of the community, especially in the the targeted area, Alue Naga. Regarding the current situation, Farmer in Alue Naga still practice the conventional method for cultivating the seaweed in the land pond. This regular method has the shortcoming in protecting the seeweed from the predators. In addition, due to the seaweed attached to the bottom of the pond, it causes the slow growth of seaweed. These circumstances cause the crops have lower quality, result in a hardly marketable product either for national or international markets. To cope with such conditions, an easy to use, reliable and safety floating house was proposed and built for the use of glacilaria seaweed culture. The community is also engaged in the workshop and construction of floating house for the glacilaria seaweed culture taught by staff of Cot Irieh Fiberlass workshop. This engagement aims to increase the insight and skill of the community regarding construction and maintenance of the glacilaria seaweed culture floating house. This study is fully supported by Syiah Kuala University Research and Community Service Institute through fostering the Alue Naga fishing community through direct application of technology

Kaji Eksperimental Kekuatan Briker Hasil Reduksi Bijih Besi Dengan Batubara Muda Menggunakan Metode Hot Briquetted Iron (HBI)

This research aims to study the mechanics (strength) properties of iron ore briquettes. Iron ore briquettes are made using the hot briquetted iron method (HBI). HBI is a briquette after reduction directly and pressed at a temperature above 650 ⁰C and has more density than 5000 kg/m3. The specimens used were iron ore briquettes made of the composition of iron ore, coal, and adhesives. The composition of the briquettes is 55: 40: 5, 65: 30: 5, 75: 20: 5, 85:10: 5 and the reduction temperature is 750⁰C,850⁰C,950⁰C and 1050⁰C. There are 16 briquett specimens. After the briquettes are made, the briquettes are reduced using a reduction blast furnance which is fuel by LPG and CO2 gas. When the mass of briquette is no longer decrease ore the time (reach steady state condition) the briquettes take out from the blast furnance for press. Pressing is carried out in hot briquettes conditions and the press load is 15 tons. The results obtained from testing the I-Type Tumbler Test have more small paricle ruptures because the briquettes have lost their adhesive during the reduction process and coal does not affect the strength of the HBI briquettes. After being reduced briquettes are given more adhesive so that briquettes can be tested again. Iron ore briquettes after reduction are stroger than those before reduction. In the variation 85:10:5 obtained from testing I-Type Tumbler Test iron ore briquettes test after reduction has a number of particle small rupture 0,21% while iron ore briquettes before reduction of 3,35%

Pemanfaatan oli bekas sebagai bahan bakar tungku peleburan logam untuk mendaur ulang kembali aluminium bekas

viii, 35 hlm. : Ilus. ; Tab. ; 29 cm