In this study, the initial operation characteristics of a multi-type cooling system with three indoor units using an inverter compressor were investigated experimentally using a calorimeter. The operating characteristics of the cooling system were confirmed under the full load condition of simultaneous operation of three rooms and the partial load condition of individual operation of two or one room under the standard cooling conditions. The capacities of A, B and C are 50, 20, and 30% of the total capacity, respectively. The 3 room combination has 100% capacity, the 2 room combination has 50, 70 and 80% capacity, and the 1 room has 20, 30, and 50% capacity. The compressor condensing and evaporating pressures, the electronic expansion valve openings of indoor units A, B, and C, and the compressor operating frequencies were measured for 10 minutes after the cooling system was started. During the initial operation, the changes in the operating time and opening of the electronic expansion valve varied depending on the indoor unit combination and the operating load, and the relationship between the compressor pressure and the operating frequency was found.

For experimental studies on the production of MR fluid for MR dampers, MR fluid with a viscosity of 506 cP and a density of 2.6 g/cc was produced. In order for MR fluid to have suitable performance for MR dampers, it is important to select surfactants, magnetic particles, base oil, and characteristic additives to obtain high damping force and maintain physical and chemical properties. In order to investigate the redispersibility of MR fluid, viscosity, density, saturation magnetic flux density, dispersibility, and temperature effects were evaluated. A particle size distribution meter and a vibrating magnetometer were used, and a yield stress and redispersion device were developed to obtain the yield stress of the MR fluid. The recovery rate of MR fluid was approximately 97% at 0.2% succinic acid coating and 8% anti-settling agent. And when current is applied, the viscosity increases by more than 90% due to magnetic properties.

In order to design a seismic safety of a cabinet affected by an earthquake, vibration analysis was performed using a model cabinet. In order to analyze the vibration characteristics of the cabinet under earthquake conditions, 3D finite element analysis was performed using ANSYS Workbench and SolidWorks. The modal analysis of the cabinet showed nine natural modes and natural frequencies, and showed the deformation and vibration of the cabinet panel for each mode. The frequencies of the 1st and 2nd modes, which are low modes, were 10% of the natural frequency value of the 9th mode, so it was easy to predict the possibility of resonance occurrence. The response spectrum due to the earthquake showed that the displacement, acceleration, and stress distribution of the cabinet had different behaviors in the x, y, and z directions, and especially showed very large values in the z direction. Although the vibration characteristics of the structure were evaluated using the modal characteristics and response spectrum for the cabinet, research on the application of a tuned mass damper is necessary for the dynamic characteristics process of the cabinet due to an earthquake and resonance reduction.

In order to understand the MR fluid flow in the MR damper core, the annular orifice path was simplified into a square channel and the electromagnetic flow was analyzed. For this purpose, the CFD-ACE+ program was used. The temperature and magnetic field of the MR fluid were based on room temperature and orifice wall data, and 2-D steady incompressible laminar flow was assumed. The inlet and outlet of the orifice channel are at atmospheric pressure, and the inflow velocity of the MR fluid is 0.1 m/s. After analyzing the magnetic field of the core, which is a simple model of the 1 stage MR damper, the electromagnetic flow analysis of the MR fluid flowing through the orifice channel was performed. From this, the magnetic field of the orifice channel and the electromagnetic flow of the MR fluid were observed. As the magnetic flux density increased, the flow distribution and velocity of the MR fluid in the channel core changed significantly.

In this study, the calorimeter was used to experimentally investigate the heating characteristics of the variable A/C system according to changes in loading time and outdoor dry bulb temperature. The heating capacity, COP and compressor discharge temperature were measured while changing the loading time of the compressor. To develop the correlation for compressor discharge temperature, loading time, indoor dry bulb temperature and outdoor dry bulb temperatures were considered as operating variables. As the outdoor temperature and loading time increased, the heating capacity and COP increased. However, the change in COP showed different trends depending on the outdoor temperature. The evaporation temperature according to the loading time is a good estimate of the outdoor temperature. However, as the temperature difference between indoor and outdoor rooms decreases and the loading time increases, the condensation pressure increases significantly, so the condensation temperature increases. The maximum deviation between the correlation and the experimental value for compressor discharge temperature was within approximately 2℃.

In this study, the calorimeter was used to experimentally investigate the cooling characteristics of the variable A/C system according to changes in loading time and outdoor dry bulb temperature. The cooling capacity, COP and compressor discharge temperature were measured while changing the loading time of the compressor. To develop the correlation for compressor discharge temperature, loading time, indoor and outdoor dry bulb temperatures, evaporation and condensation temperatures were considered as operating variables. As the loading time increased, the cooling capacity and COP increased. The cooling capacity increased linearly with the loading time. The COP increased more at low loading times than at high loading times. The change in condensing temperature according to the loading time had a small temperature fluctuation range, and the evaporation temperature decreased linearly. The compressor discharge temperature increased linearly with the loading time and outdoor temperature, and the maximum deviation between the experimental value and the correlation was within about 2℃.

In this study, the operating performance of the heat pump dryer using the PF heat exchanger was experimentally studied. The capacity, COP, drain, SMER and operating status of the cooling cycle of the heat pump dryer were investigated according to the temperature, relative humidity and flow rate of the indoor air. Heat pump dryers are refrigerant-air system. For the dryer performance experiment, an air enthalpy calorimeter was used. From the experimental results, as the temperature, relative humidity, and flow rate of the inlet air increased, the capacity, COP, drain, SMER of the dryer increased. The change in the performance of the dryer was most affected by temperature. The P-h diagram of the cooling system showed that the operation status of the dryer was greatly affected by the indoor temperature. In addition, the SMER of the dryer showed a drying performance of about 3.38 kg/kWh or more within all experimental ranges.

In the present study, the inertial electromagnetic actuator (IEA) and the FxLMS (filtered-x least mean square) method were applied to study vibration control using the active mount. IEA was designed and manufactured for the experiment, and FxLMS algorithm was developed to evaluate control performance and mount dynamic characteristics. For the vibration control experiment, active mounts were installed at the top and bottom, and the lower active mount controls the force transmitted to the structure by the excitation signal from the upper active mount. The experiment was performed by simultaneously exciting three frequencies in three axes. From the experimental results, it was confirmed that the force measured at the lower active mount when the actuator is off is greatly reduced when the actuator is on, and that vibration reduction in the vertical z-axis is more effective than vibration reduction in the x-y plane.

In the present study, a calorimeter was used to experimentally investigate the heating capacity and COP changes according to the pipe length of a variable capacity A/C system with long pipes. Cooling capacity, COP, and compressor discharge temperature were obtained by changing pipe lengths and loading duties at fixed indoor and outdoor temperatures. And the operation status and cycle change process of the A/C system were investigated using some experimental data and P-h diagrams. As the pipe length changes, the heat transfer within the cycle and the operating load of the compressor change, so the heating capacity and COP of the system change. At the same loading duty, as the pipe length increases, the heating capacity and COP decrease. As the loading duty increased, the heating capacity increased almost linearly, but the COP decreased. Since the long pipe experimental value for the compressor discharge temperature has a temperature deviation of up to 1 7℃(50m, L/D : 10/10) from the correlation equation, the optimal correlation equation must be derived through additional research.

In the present study, a calorimeter was used to experimentally investigate the cooling capacity and COP changes according to the pipe length of a variable capacity A/C system with long pipes. Cooling capacity, COP, and compressor discharge temperature were obtained by changing pipe length and loading duty. And the operation status and cycle change process of the A/C system were investigated using some experimental data and P-h diagrams. In long pipes, the pressure drop increases and the operating load on the compressor increases. Additionally, at the same loading duty, cooling capacity and COP decrease and the compressor discharge temperature increases. As loading duty increases, cooling capacity and compressor power consumption increase. Since the temperature deviation between the experimental value and the correlation equation for the discharge temperature of the long-pipe compressor shows a maximum of 10.5℃(50m, L/D : 20/0), the existing correlation equation needs to be modified.

In this study, the heating performance of a variable capacity A/C system was experimentally studied. A psychrometric calorimeter was used to obtain performance data of the A/C system using PWM(pluse width modulation) method and compare it with the compressor discharge temperature correlation equation. Heating capacity, COP, and compressor discharge temperature were obtained by changing indoor and outdoor temperatures, refrigerant amount, and loading duty. The following results were obtained by selecting 5 types of refrigerant amount, 3 types of outdoor temperature (fixed indoor temperature), and 2 types of loading duty. As the outdoor temperature increases, heating capacity and COP increase. Heating capacity was affected by both outdoor temperature and loading duty. However, COP was more influenced by outdoor temperature. The effect of increasing the amount of refrigerant on the performance of the A/C system was not significant. Additionally, the temperature deviation between the existing compressor discharge temperature correlation equation and the heating experiment data was about 5.1℃ at the maximum loading duty.

In this study, the cooling performance of a variable capacity A/C system was experimentally studied. A psychrometric calorimeter was used to obtain performance data of the A/C system using the pulse width modulation method and compare it with the compressor discharge temperature correlation equation. Cooling capacity, COP, and compressor discharge temperature were obtained by changing indoor and outdoor temperatures, refrigerant amount, and loading duty. The following results were obtained by selecting 5 types of refrigerant amount, 3 types of outdoor temperature (fixed indoor temperature), and 2 types of loading duty. As the outdoor temperature increased, cooling capacity and COP according to outdoor conditions decreased. And the higher the loading duty, the greater the cooling capacity, but the COP was minimal. The change in cooling capacity and COP due to the increase in refrigerant amount was not significant. Additionally, the change in compressor discharge temperature is more influenced by the outside temperature than by the loading duty.

In the present study, the experimental study was conducted using a multi-calorie meter, to investigate the cooling performance and cycle operation changes of the multi-heat pump (3 indoor units) for the low outside temperature in summer. The test temperature condition was the low cooling temperature, and the normal performance and dynamic behavior of 3 rooms, 2 rooms, and 1 room were measured to understand the operating characteristics of seven 7 indoor unit combinations. As a result of the experiment, the cooling capacity and COP of the multi-heat pump at low cooling temperature were about 10% and 6% higher than those of the cooling standard temperature. In addition, the dynamic behavior of the indoor units of 3 and 2 rooms was observed differently due to the load difference according to the indoor unit combinations and the non-uniformity of the refrigerant amount. And, when starting the heat pump, the compressor had a maximum peak value and stabilized by repeating the decrease and increase for each indoor unit combination.

In the present study, to investigate the cooling characteristics of the multi-heat pump with 3 indoor units, 7 indoor unit combinations and 3 setting temperatures are selected to study the cooling characteristics during steady-state operation. The cooling capacity, power consumption, COP, compressor high and low pressure of the heat pump are tested under the cooling standard temperature conditions using an air enthalpy multi-calorimeter. The experimental results show that, except for an operation with an indoor unit capacity of 30% or less, the cooling capacity, power consumption, and compressor operation frequency increase as the capacity of the indoor unit increases and the setting temperature of the indoor unit decreases. COP increases or decreases according to the compressor frequency, and is the best at 50-80% capacity of the indoor unit. As the compressor frequency increases, the compressor outlet pressure increases by about 30%.

In order to experimentally investigate the operation characteristics of the multi-heat pump with 3 indoor units, the dynamic characteristics of the cooling cycle is studied using the psychrometric multi-calorimeter. The compressor of the heat pump is the scroll inverter type, and since 3 indoor units operate cooling at the same time, it is operated at 100% full load. In particular, 3 types of indoor unit temperatures (20, 24, 26°C) are selected to understand the operation process of the multi-heat pump by the setting temperature. From this experiment, the compressor controls the EEV opening for each indoor unit while varying the frequency according to the initial start, transient, and steady operation. In addition, as the setting temperature increases in the steady range, the frequency of the compressor and the average opening degree of the EEV decrease.

In the present study, it is conducted to understand the heating performance and compressor operation characteristics according to 7 indoor unit combinations and 3 setting temperatures of the inverter multi-heat pump under heating standard temperature conditions. Heating capacity, COP and compressor frequency are investigated using the multi-calorimeter. The indoor unit combinations are simultaneous operation(A+B+C), partial operation(A+C, A+B, B+C) and independent operation(A, B, C), and the setting temperature is 20, 21, and 30°C. Since the increase in the setting temperature increases the compress frequency, the heating capacity increases, but COP decreases due to the increase in power consumption. The frequency increases as the indoor unit combination capacity increases, and decreases as the setting temperature decreases in the steady state.

The performance characteristics and usefulness of the duct-type gas removal system to which the catalytic combustion method was applied were investigated by experiment. Benzene, toluene, ethylbenzene, and xylene were selected for performance tests on gas detection and removal of the catalytic combustion system. Accelerated experiments were performed to evaluate the gas sensing performance, the adsorption performance of activated carbon, and the basic performance and durability of the catalytic combustion system. The amount of gas adsorption in the adsorption stage was changed according to the type of activated carbon, adsorption temperature and time. The adsorption amount increased with increasing temperature and particle size. BTEX gas removal rate was about 96%, and the performance of the module was maintained for more than 4,000 hours.

In this paper, a heat exchange system using cooling dehumidification and mixing process was proposed as an experimental study for a white smoke reduction heat exchanger system under winter condition. The white smoke reduction heat exchange system is divided into an EA part, SA part, W part and mixing zone. For the operating conditions, three types (Cases 1, 2, and 3) were selected depending on whether EA fan, SA fan, and A-W heat exchanger were operated. In addition, in order to visualize the white smoke exhausted from the mixing zone, it was photographed using CCTV. In order to investigate the performance of the white smoke reduction heat exchange system, the temperature reduction rate and absolute humidity reduction rate of EA and the heat recovery rate of W were calculated. The temperature change of EA and SA according to operating conditions was most effective in Case 3, and the temperature and absolute humidity at the outlet of the mixing zone were greatly reduced. From the results of the white smoke visualization, it was confirmed that the white smoke generation mechanism was different depending on the operating conditions, and the amount of white smoke generation was greatly reduced.

In order to study the drying performance of the dryer, the performance characteristics of the heat pump dryer applied a PF heat exchanger is applied were experimentally investigated. The capacity, COP, drain and SMER of the dryer were measured by the refrigerant charge and EEV opening. Heat pump dryers are refrigerant-air systems. For the dryer performance test, an air enthalpy calorimeter was used. From the experimental results, the heat exchanger performances according to the change in the refrigerant charge and EEV opening were the maximum at 0.5kg refrigerant and 30% EEV opening, respectively. In addition, SMER suggested a satisfactory level of drying performance. This shows that the refrigeration cycle of the dryer must be operated at an appropriate refrigerant amount and EEV opening degree to secure optimal drying performance. On the other hand, the time to reach the target setting temperature of the dryer was increased by about 2.5 times depending on with/without the sample.

Driving safety of a semi-trailer is greatly reduced when driving in a section with a narrow turning radius, so a dynamic study of driving and road conditions is required. In this study, the driving stability of the semi-trailer was investigated using the RecurDyn program in consideration of the velocity and weight of the semi-trailer in the entrance curve section of the highway, and the turning angle and radius of the curved road. In order to select the model and analysis conditions according to the road type, the sloping curved road was modeled by selecting the curvature, entry length, height difference, and entrance angle of the curved section. From the analysis results, the higher the semi-trailer's entrance velocity, the heavier the weight, the narrower the entrance angle of the curved road, and the smaller the curvature, the greater the semi-trailer's maximum running angular speed which had an effect on driving stability.