• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.1264-1269
• /
• 2004

This research describes the application of hydrocarbon refrigerants for heat pump system which is needed for fish farm. Tested refrigerants are HCFC-22 and hydrocarbon refrigerants(CARE 50 and ASR-20). CARE 50 is mixture of R-290 and R-170, and ASR-20 is mixture of R-152a, R-290 and other additives. Heat pump consist of shell and tube heat exchanger, scroll compressor, expansion valve and accumulator. Manual expansion valve is used for testing of wide range evaporating temperature. Hydrocarbon refrigerants show a good performance as an alternative for HCFC-22 in the range of evaporating temperature from $-6^{\circ}C$ to $6^{\circ}C$.

• 설비공학논문집
• /
• 제10권6호
• /
• pp.683-694
• /
• 1998

The application of hydrocarbon refrigerants in a hermetic reciprocating compressor for refrigerator is investigated. The selected refrigerants are isobutane(R600a), propane(R290), R12, binary mixture of R600a/R290, and OS-21CII. Both theoretical and experimental investigations have been performed for the selected refrigerants. The test results of hydrocarbon refrigerants have been compared to the traditional refrigerant(R12). The results show that hydrocarbon refrigerants(HC-Blend, OS-21C II) are very good alternatives in the refrigeration system for R12.

• 설비공학논문집
• /
• 제4권4호
• /
• pp.332-341
• /
• 1992

An absorption heat pump cycle has been modeled and simulated to analyze the system performance of water-cooled, series-flow, double-effect absorption heat pump, which can be applied to a direct gas fired cooling system with the medium range of cooling capacity (15RT level). Effect of absorption cooling system parameters, such as concentration difference, inlet temperature of cooling water, 1st generator temperature, leaving temperature differences of condenser and evaporator and efficiency of solution heat exchanger, has been investigated in the view of system cooling performance.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.731-734
• /
• 2001

A cryogenic stirling cooler is currently under development at Korea Institute of Industrial Technology(KITECH). Cryocooler has many kinds of types. The stirling cooler is the most appropriate one for under 80K with the trait of long life cycle and small size. The stirling cooler uses helium as a working fluid. Helium is pressurized by the linear compressor which is driver by linear motor. In this paper, the change of pressure and volume is studied by the isothermal analysis method. It is necessary to investigate the optimized pressure to meets the highest COP. The compressor's piston and expender's displacer interact according to the working fluid's pressure level and the phase difference. This paper presents the relation between the initial pressure and the work of cryocooler. By that results, we can predict the performance of linear compressor.

• 설비공학논문집
• /
• 제24권10호
• /
• pp.733-738
• /
• 2012

It is important issue to reduce the electric energy to save the operating cost of HVAC system. Even if electrical energy is the clean energy, it is difficult and takes high cost for storage of electricity. These cause the high peak load of electric energy for HVAC in summer season. In korea, government impose the electric charge with several grade for the purpose of cut-off the peak load of electricity. Government has a policy to support to design and install the heat/ice storage system using midnight electricity. In this study, analysis of cooling load and operating characteristics for ice storage system are performed. And, also economical efficiency is compared between ordinary charge system of electricity and midnight rate charge of electricity. The systematic and economical supports are needed for expansion of usage of energy saving equipments.

• 한국지열·수열에너지학회논문집
• /
• 제14권3호
• /
• pp.29-34
• /
• 2018

To present the design direction of the thermoelectric module (TEM) refrigerator, analysis of the effect of the design parameters on the energy efficiency and performance of the refrigerator is performed. The design parameters considered are the cooling capacity of the TEM and the heat transfer performance of the heating and cooling surface of the TEM. The heat transfer performance is the most effective design parameter for improving cooling power. The smaller ΔT and cooling capacity of the TEM make the higher efficiency of the refrigerator.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집B
• /
• pp.216-221
• /
• 2000

Most Ice making companies make simple efforts to make products and fail to introduce improvements into the system against huh cost of products. The work presented here is an implementation of ice making method to improve both energy efficiency and productivity. In this present investigation, several ice making cycles are designed and calculated to evaluate COP, ice making time and electric energy consumption. Results obtained shows that COP is improved with more efficient use of time for ice making and electric consumption. Therefore this can offer the opportunity for more efficient energy consumption and productivity in ice making.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2002년도 학술대회지
• /
• pp.647-650
• /
• 2002

A thermoacoustic refrigerator, using a resonant standing acoustic wave, has been built. It employs a loudspeaker to sustain a standing wave in a resonance tube. The stack of plates is 0.075mm-thick plastic sheet(Mylar), spirally wound to make a 40mm-diameter assembly 80mm long. and two heat exchanger are installed. The refrigerant is Helium gas. The description of thermoacoustic refrigerator are presented. The directly measured performance of the resonator. Tc/Th ( temperature ratio ) and $COP/COP_{c}$, (normalized by carnot's COP ) are plotted versus the thermal load Q applied to the cold end, for various speaker power.

• 설비공학논문집
• /
• 제16권1호
• /
• pp.62-69
• /
• 2004

Thermoelectric module is a device that can produce cooling in a direct manner using the electrical energy. The purpose of this study is to investigate the performance of thermoelectric module and cooling system equipped with the thermoelectric module. The performance of a thermoelectric module is estimated using two methods; theoretical analysis based on one-dimensional energy equations and experimental tests using heat source, heat sink and brass conduction extenders. For the thermoelectric cooling system, the temperatures in the chamber are recorded and then compared with those of lumped system analysis. The results show that the cooling capacity and COP of the thermoelectric module increases as the temperature difference between hot and cold surface decreases, and there is particular current at which cooling capacity reaches its maximum value. The experimental results for the thermoelectric cooling system are similar to those of lumped system analysis.

• 설비공학논문집
• /
• 제27권5호
• /
• pp.269-276
• /
• 2015

Single-effect $CH_3OH-LiI-ZnBr_2$ and $C_2H_5OH-LiI$ absorption heat pumps are simulated to evaluate feasibility as heating device. These systems are predicted to give higher heating COPs in wide operating ranges compared to conventional systems. Among the two systems, the $C_2H_5OH-LiI$ system is found to be more advantageous for operating in extremely cold weather due to the large solubility of Lil in $C_2H_5OH$.