Perancangan Cold Storage Untuk Sayuran Buncis Dengan Kapasitas 10 Ton

Abstrak Buncis merupakan salah satu produk pertanian di Indonesia yang diekspor ke luar negeri. Setelah dipanen, buncis disimpan untuk diproses sebelum diekspor ke konsumen. Kesegaran buncis umumnya hanya bertahan selama 1 minggu, oleh karena itu diperlukan alat khusus untuk mempertahankan kesegaran buncis sebelum diekspor ke konsumen. Untuk mempertahankan kesegaran buncis, temperatur udara 4°C-7°C dengan kelembaban 90%-95% perlu dipertahankan. Dengan menggunakan cold strorage, kondisi ruang penyimpanan dapat diatur sedemikian rupa agar memenuhi kriteria tersebut. Pada penelitian ini dirancang sebuah cold storage dengan kapasitas 10 ton untuk tanaman buncis. Cooling Load Temperatur Difference (CLTD) pada perancangan ini diatur bulan dan waktunya yang disesuaikan dengan posisi dari cold storage. Beban pendinginan total untuk 10 ton buncis adalah sebesar 46,73 kW. Cold storage hasil rancangan menggunakan siklus kompresi uap dengan fluida refrigeran R134a tanpa menggunakan humidifier. Untuk mempertahankan kondisi udara pada cold storage agar sesuai dengan kebutuhan, kompressor AC dengan kapasitas 12,7 kW digunakan pada siklus kompresi uap. Performa dari siklus kompresi uap dengan kondisi operasi tersebut ditentukan oleh Coefficient of Performance (COP). Semakin besar nilai COP, maka sistem semakin efisien. Coefficient of Performance (COP) dari siklus tersebut adalah sebesar 3,84. Kata kunci: Buncis, CLTD, Refrigeran, COP, Siklus kompresi uap Abstract Snap beans are one of Indonesian acgricultural product exported to overseas. After harvested, snap beans were stored before exported to consumers. The freshness of the snap beans only lasted for one week, therefor special equipment were required to maintain the snap beans freshness. To maintain the freshness, snap beans must be storage in a room with 4-7°C air temperature and 90-95% humidity. In this research, cold storage was designed for 10 tons of snap beans. Cooling Load Temperature Difference method was used to determine the load of the cold storage based on the position of the building. The total cooling load for 10 tons of snap beans were 46,73 kW. The cold storage was using vapor compression cycle with refrigerant 134a without humidifier . The cycle requires compressor power of 12,7 kW to maintain the condition in the cold storage room. The performance of the cycle was determined from the Coefficient of Performance (COP). The higher value of the COP, the system will be more efficient. The COP of the vapor compression cycle was 3,84. Key words: Snap Beans, Export, Refrigerant, Storage, Humidity.

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KAJI PERFORMANSI REFRIGERAN R-290, R-32, DAN R-410A SEBAGAI ALTERNATIF PENGGANTI R-22

ALE Proceeding ◽

10.30598/ale.4.2021.133-139 ◽

2021 ◽

Vol 4 ◽

pp. 133-139

Author(s):

Rikhard Ufie ◽

Cendy S. Tupamahu ◽

Sefnath J. E. Sarwuna ◽

Jufraet Frans

Keyword(s):

Air Conditioning ◽

Cooling Capacity ◽

Coefficient Of Performance ◽

Condensation Temperature ◽

Vapor Compression ◽

Know How ◽

Evaporation Temperature ◽

Vapor Compression Cycle ◽

Compression Cycle ◽

Refrigeration Capacity

Refrigerant R-22 is a substance that destroys the ozone layer, so that in the field of air conditioning it has begun to be replaced, among others with refrigerants R-32 and R-410a, and also R-290. Through this research, we want to know how much Coefficient of Performance (COP) and Refrigeration Capacity (Qe) can be produced for the four types of refrigerants. The study was carried out theoretically for the working conditions of the vapor compression cycle with an evaporation temperature (Tevap) of 0, -5, and -10oC, a further heated refrigerant temperature (ΔTSH) of 5 oC, a condensation temperature (Tkond) of 45 oC and a low-cold refrigerant temperature. (ΔTSC) 10 oC and compression power of 1 PK . The results of the study show that the Coefficient of Performance (COP) in the use of R-22 and R-290 is higher than the use of R-32 and R-410a, which are 4,920 respectively; 4,891; 4.690 and 4.409 when working at an evaporation temperature of 0 oC; 4.260; 4,234; 4.060 and 3.812 when working at an evaporation temperature of -5 oC; and amounted to 3,730; 3,685; 3,550 and 3,324 if working at an evaporation temperature of -10 oC. Based on the size of the COP, if this installation works with a compression power of 1 PK, then the cooling capacity of the R-22 and R-290 is higher than the R-32 and R-410a, which are 3,617 respectively. kW; 3,597 kW; 3,449 kW and 3,243 kW. If working at an evaporation temperature of 0 oC; 3.133 kW; 3.114 kW; 2,986 kW and 2,804 kW if working at an evaporation temperature of -5 oC; and 2,741 kW; 2,710 kW; 2,611 kW and 2,445 kW if working at an evaporation temperature of -10oC.

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Decentralized Feedback Structures of a Vapor Compression Cycle System

ASME 2008 Dynamic Systems and Control Conference, Parts A and B ◽

10.1115/dscc2008-2213 ◽

2008 ◽

Cited By ~ 3

Author(s):

Brandon Hencey ◽

Neera Jain ◽

Bin Li ◽

Andrew Alleyne

Keyword(s):

Multiple Input Multiple Output ◽

Thermodynamic Cycle ◽

Coefficient Of Performance ◽

Vapor Compression ◽

Input Output ◽

Single Input Single Output ◽

Loop Design ◽

Cycle System ◽

Vapor Compression Cycle ◽

Compression Cycle

In vapor compression cycle (VCC) systems, it is desirable to effectively control the thermodynamic cycle. By controlling the thermodynamic states of the refrigerant with an inner-loop, supervisory algorithms can manage critical objectives such as maintaining superheat and maximizing the coefficient of performance, etc. In the HVAC industry, it is generally preferred to tune multiple single-input-single-output (SISO) control inner-loops rather than a single multiple-input-multiple-output (MIMO) control inner-loop. This paper presents a process by which a simplified feedback control structure amenable to a decoupled SISO control loop design may be identified. In particular, the many possible candidate input-output pairs for decentralized control are sorted via a decoupling metric, the relative gain array number. From a reduced set of promising candidate input-output pairs, engineering insight is applied to arrive at the final pairings successfully verified on a refrigeration test stand.

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Theoretical thermodynamic performance assessment of various environment-friendly novel refrigerants used in refrigeration systems

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406219884968 ◽

2019 ◽

Vol 234 (4) ◽

pp. 914-934 ◽

Cited By ~ 2

Author(s):

Sharmas Vali Shaik ◽

TP Ashok Babu

Keyword(s):

Global Warming ◽

Environmental Impact ◽

Performance Assessment ◽

Coefficient Of Performance ◽

Vapor Compression ◽

Environment Friendly ◽

Refrigerant Mixture ◽

Vapor Compression Cycle ◽

Compression Cycle ◽

Thermodynamic Performance

The present investigation focuses on theoretical performance of various new environment-friendly refrigerant mixtures as substitutes to high global warming potential refrigerant R22. In this investigation, 34 refrigerants were considered at various composition. In this work, both complex vapor compression cycle (actual cycle) and standard vapor compression cycle (ideal cycle) was considered for the performance assessment of refrigerants. Vital studies such as flammability, toxicity, and environmental impact of various novel refrigerants were also carried out in this study. Results obtained from actual cycle showed that the coefficient of performance of refrigerant mixture RM40 (R1270/R134a 90/10 in mass %) (2.728) was the greatest among 34 investigated alternatives and it was closer to the coefficient of performance of R22 (2.770). Compressor discharge temperature of RM40 was 13.36 ℃ lower when compared with R22. Volumetric refrigeration capacity of RM40 (3335 kJ/m3) was slightly higher than that of R22 (3297 kJ/m3). Power spent per ton of refrigeration of RM40 (1.288 kW/TR) was marginally higher than that of R22 (1.269 kW/TR). Global warming potential (GWP100) of RM40 (133) was very low compared to the GWP100 of R22 (1760). Total equivalent warming index (environmental impact) of RM40 was 5.61% lower than R22. However, performance results obtained from standard cycle for various investigated refrigerants were better than actual cycle, since various losses occur were neglected in the standard cycle. Overall, thermodynamic performance of refrigerant mixture RM40 (R1270/R134a 90/10 in mass %) obtained from both actual and standard cycle was the highest among 34 investigated refrigerants and it was very closer to the performance of R22 and hence, it could be considered as an environment-friendly alternative to replace high GWP refrigerant R22 used in refrigeration systems.

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Viability of Spray Cooling an Air-Cooled Condenser in a Personnel Microclimate Cooling System

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4007207 ◽

2012 ◽

Vol 4 (4) ◽

Author(s):

Brent A. Odom ◽

Patrick E. Phelan

Keyword(s):

Air Temperature ◽

Cooling System ◽

Cooling Water ◽

Ambient Air ◽

Spray Cooling ◽

Vapor Compression ◽

Vapor Compression Cycle ◽

Compression Cycle ◽

Compressor Work ◽

Microclimate Cooling

Attaining a reasonable size and weight for a personnel microclimate cooling system for an individual person who operates away from logistical support remains a problem. This work analyzes whether spray cooling the ambient air before it cools the condenser in a small vapor compression cycle is worthwhile in terms of battery weight savings. The analysis specifies essential characteristics of each of the main components of an ideal vapor compression cycle in order to determine equations describing their expected performance. Then, a mathematical technique is used to find balance points for the model system at different ambient air temperatures. The balance points show the decrease in condensing temperature and compressor work that result from a decrease in ambient air temperature. The saved compressor work is converted to battery weight savings and compared to the weight of water required to reduce the air temperature. It is found that the potential battery weight savings do not offset the amount of cooling water required, i.e., spray cooling the air-cooled condenser should not be pursued to decrease system weight.

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The Steady-State Modeling and Analysis of a Two-Loop Cooling System for High Heat Flux Removal

Volume 9: Heat Transfer, Fluid Flows, and Thermal Systems, Parts A, B and C ◽

10.1115/imece2009-11500 ◽

2009 ◽

Cited By ~ 1

Author(s):

Rongliang Zhou ◽

Juan Catano ◽

Tiejun Zhang ◽

John T. Wen ◽

Greg J. Michna ◽

...

Keyword(s):

Heat Flux ◽

Steady State ◽

Heat Exchangers ◽

Cooling System ◽

High Heat ◽

System Structure ◽

High Heat Flux ◽

Vapor Compression ◽

Vapor Compression Cycle ◽

Compression Cycle

Steady-state modeling and analysis of a two-loop cooling system for high heat flux removal applications are studied. The system structure proposed consists of a primary pumped loop and a vapor compression cycle (VCC) as the secondary loop to which the pumped loop rejects heat. The pumped loop consists of evaporator, condenser, pump, and bladder liquid accumulator. The pumped loop evaporator has direct contact with the heat generating device and CHF must be higher than the imposed heat fluxes to prevent device burnout. The bladder liquid accumulator adjusts the pumped loop pressure level and, hence, the subcooling of the refrigerant to avoid pump cavitation and to achieve high critical heat flux (CHF) in the pumped loop evaporator. The vapor compression cycle of the two-loop cooling system consists of evaporator, liquid accumulator, compressor, condenser and electronic expansion valve. It is coupled with the pumped loop through a fluid-to-fluid heat exchanger that serves as both the vapor compression cycle evaporator and the pumped loop condenser. The liquid accumulator of the vapor compression cycle regulates the cycle active refrigerant charge and provides saturated vapor to the compressor at steady state. The heat exchangers are modeled with the mass, momentum, and energy balance equations. Due to the projected incorporation of microchannels in the pumped loop to enhance the heat transfer in heat sinks, the momentum equation, rarely seen in previous refrigeration system modeling efforts, is included to capture the expected significant microchannel pressure drop witnessed in previous experimental investigations. Electronic expansion valve, compressor, pump, and liquid accumulators are modeled as static components due to their much faster dynamics compared with heat exchangers. The steady-state model can be used for static system design that includes determining the total refrigerant charge in the vapor compression cycle and the pumped loop to accommodate the varying heat load, sizing of various components, and parametric studies to optimize the operating conditions for a given heat load. The effect of pumped loop pressure level, heat exchangers geometries, pumped loop refrigerant selection, and placement of the pump (upstream or downstream of the evaporator) are studied. The two-loop cooling system structure shows both improved coefficient of performance (COP) and CHF overthe single loop vapor compression cycle investigated earlier by authors for high heat flux removal.

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Rechargeable Personal Air Conditioning Device

Volume 1: Biofuels, Hydrogen, Syngas, and Alternate Fuels; CHP and Hybrid Power and Energy Systems; Concentrating Solar Power; Energy Storage; Environmental, Economic, and Policy Considerations of Advanced Energy Systems; Geothermal, Ocean, and Emerging Energy Technologies; Photovoltaics; Posters; Solar Chemistry; Sustainable Building Energy Systems; Sustainable Infrastructure and Transportation; Thermodynamic Analysis of Energy Systems; Wind Energy Systems and Technologies ◽

10.1115/es2016-59253 ◽

2016 ◽

Cited By ~ 1

Author(s):

Yilin Du ◽

Jan Muehlbauer ◽

Jiazhen Ling ◽

Vikrant Aute ◽

Yunho Hwang ◽

...

Keyword(s):

Air Conditioning ◽

Cooling System ◽

Cooling Capacity ◽

Comfort Level ◽

Vapor Compression ◽

Air Conditioning System ◽

System A ◽

Single Person ◽

Vapor Compression Cycle ◽

Compression Cycle

A rechargeable personal air-conditioning (RPAC) device was developed to provide an improved thermal comfort level for individuals in inadequately cooled environments. This device is a battery powered air-conditioning system with the phase change material (PCM) for heat storage. The condenser heat is stored in the PCM during the cooling operation and is discharged while the battery is charged by using the vapor compression cycle as a thermosiphon loop. The conditioned air is discharged towards a single person through adjustable nozzle. The main focus of the current research was on the development of the cooling system. A 100 W cooling capacity prototype was designed, built, and tested. The cooling capacity of the vapor compression cycle measured was 165.6 W. The PCM was recharged in nearly 8 hours under thermosiphon mode. When this device is used in the controlled built environment, the thermostat setting can be increased so that building air conditioning energy can be saved by about 5–10%.

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