• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.18 no.9
• /
• pp.707-713
• /
• 2006

To improve heating performance of the heat pump in winter season, refrigerant heating device was applied to conventional heat pump. The refrigerant heating device operates at the heating capacity does not enough to the heating load requirement of the conditioning space. When the discharge air temperature of the indoor heat exchanger goes down to below $40^{\circ}C$ which is criterion for comfort of the occupants in the conditioning space, the system also starts. The refrigerant heating system has new concept of auxiliary heating device for heat pump in winter. In this study, the system performance was analyzed through experiments and parametric study was conducted to improve the COP and control strategies.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.6
• /
• pp.65-70
• /
• 2020

In this paper, to establish a high-efficiency air-conditioning and heating system, we developed a simultaneous air-conditioning and heating system that can do both air-conditioning and heating at the same time. It was applied to hybrid plant plants to enable automation of complex farms. For this purpose, the heat exchanger, which functions as a condenser during heating, was required to function as an evaporator during cooling so that air conditioning and heating could be implemented simultaneously. For experiments, the simultaneous air conditioning system for heating and cooling was produced and applied to the plant factories in the farms so that plants could be grown, stored, and dried. As a result, a single system was able to control the temperature environment of agricultural products with an energy-saving system that simultaneously resolves heating and cooling. Therefore, efficient crop management was possible by implementing an air conditioning system that did not require installing air conditioners and boilers at the same time.

• Journal of the Korea Institute of Building Construction
• /
• v.4 no.2
• /
• pp.105-112
• /
• 2004

The objective of this study is to observe today's situation and direction in relation with the natural air-conditioning and heating system to expand the architectural utilization of natural management for human comfort and energy conservation in architectural design. Also this study to provide the fundamental knowledge and. design-techniques on environment-friendly architecture in connection with 'natural idea in architecture'. In accordance with this intention, this thesis is composed of the following contents : 1) to understand the fundermental concepts about natural air-conditioning and heating system, 2) to review the traditional characteristics in Korean and Southeast Asian architecture related to natural air-conditioning and heating system, 3) to examine modern design-techniques in relation with natural air-conditioning and heating system in the selected area, 4) to attempt to synthesize the whole situation. Environment-friendly architecture using natural ideas and design-techniques in architecture is very important architectural aspect in a current architecture, also for the future. In spite of general considerations, it is expected that this study is use to understand the principle and practical application of natural air-conditioning and heating system in architectural design.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.8 no.1
• /
• pp.76-87
• /
• 1996

Energy analysis for the hot water heating control system of apartment house complex is accomplished by computer simulation. Mathematical model of a boiler, pipe network and a unit-house is developed. The effects of heating control methods on the heating performance and energy consumption of the system are investigated. The heating control methods considered in this study are a continuous heating control, and on-off heating control and an intermittent heating control methods. For each control method, the effects of an outdoor temperature, indoor temperature sensing position and the capacities of the boilers and circulating pumps on the heating performance and energy consumption are obtained and "the best" control method is recommended.commended.

• Proceedings of the KSME Conference
• /
• 2001.06d
• /
• pp.158-163
• /
• 2001

Performance of the water direct contact air conditioning system, in which heat and mass are transferred directly between air and water droplet, is simulated by semi-empirical method. This system improves transport efficiency compared to conventional indirect contact system and cooling, heating, dehumidification and humidification are attained with one unit. In this study, temperature and flowrate for air and water are measured in the various cooling and heating conditions, and correlations for $h_{c}A/c_{pm}$ are derived from these data. Cooling and heating characteristics of the water direct contact air conditioning system are investigated using correlations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.30 no.3
• /
• pp.149-157
• /
• 2018

In this research, the psychological and physiological reactions of the driver were measured during winter to evaluate thermal comfort. The experiment was conducted using 3 different cases which are hot air heating, warm-wire seat heating and hot air & warm-wire seat heater operating simultaneously. With regard to psychological reaction, the warm-wire heating mode was the most preferred. The reason is that it is dry in other cases. With regard to EEG response, thermal comfort increased by 37% in warm air mode heating. In addition, when the warm-wire heating mode and the hot air & warm-wire heating mode were simultaneously operated, the thermal comfort continuously increased by between 17% and 20% for 20 minutes after boarding. Under the change of the autonomic nervous system, the thermal stress level increased by 23% after 15 minutes on board in the hot air heating mode and decreased continuously by 13% during the warm-wire seat heating mode. We recommended the hot air heating mode is only used for a short time to raise the inside temperature during the early boarding period and that warm-wire seat heating mode be actively utilized.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.23 no.1
• /
• pp.5-8
• /
• 1994

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.12
• /
• pp.1035-1042
• /
• 2003

As the desire for a better condition in classroom increases, the distribution rate of warming and cooling conditioners increases. But it is known that according to the way by which the equipments put and are operated the comfortableness felt by persons who are in classroom can make a difference. Therefore, proper equipments in accordance with the size of classroom should be considered as well as operational methods when ceiling warming and cooling conditioners put. This study makes conclusions as follows through a simulation to get improvements in accordance with the size of classroom and to improve the heating performance of ceiling warming and cooling conditioners in classroom.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.4 no.3
• /
• pp.191-203
• /
• 1992

To analyze the unsteady heat transfer phenomena in radiant heating panel, a mathematical model was considered. Numerical analysis for solving the governing equations was conducted by using the finite difference method with boundary-fitted meshes. Transient temperature distributions and thermal responses in heating panel were obtained for various design parameters such as pipe pitches, pipe diameters and pipe depths. Experimental results were also obtained to verify the results of calculation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.6
• /
• pp.337-344
• /
• 2010

Good plant-growth conditions can be achieved by means of using greenhouses. One of the main issues in greenhouse cultivation is energy savings through the development of high efficient heating and cooling system. GSHPs are one of the recommended systems to cope with this pending need. The aim of this study is to investigate the heating performance of ground source multi-heat pump system installed in a greenhouse under part load conditions. Daily average heating COP of the heat pump unit was very high by at least 7.4, because of relatively large condenser, evaporator, and mass flow rate through ground loop heat exchanger. However, the system COP, overall heating coefficient of the performance of the system with heat pump unit and GLHX, decreased drastically due to relatively large power consumption of circulating pump under part load condition. It is suggested that the technology to enhance the performance of the ground source multi-heat pump system for a greenhouse under part load conditions should be developed.