• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1218-1226
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• 2004

This paper presents thermal behaviors and performances of a fresh air load reduction system by using earth tube system combined with air-heated solar collector. The earth tube system reduces a fresh air load by heat exchange with soil throughout the year. In the previous experimental research, it was clarified that the earth tube system was very useful as a fresh air load reduction system. However, since outlet temperature of the fresh air which was heated by earth tube system was below 15$^{\circ}C$ in winter, it is not suitable to introduce the fresh air into the place of residence directly. Therefore, a simulation model using the simple heat diffusion equation was used to examine a rising effect of outlet air temperature in winter by combining with air-heated solar collector. An improvement of annual performance by control of operation is also quantitatively examined. In conclusion, it is confirmed that its performance is improved by control of operation throughout the year and outlet air temperature rose by combining with air-heated solar collector.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.4
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• pp.331-340
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• 2004

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we used a model for evaluation of fresh air latent heat load reduction by hygroscopic of air to earth exchange system taking into account coupled heat and moisture transfer of underground double floor space. In conclusion it shows the validity of the proposed method for a design tool and the quantitative effect of the system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.9
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• pp.620-627
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• 2010

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we investigated the correlation between outdoor air temperature and outlet air temperature in the system. In conclusion, from the results of the high correlation we proposed a equation of regression for the outlet air temperature in the system by using linear regression analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.9
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• pp.628-634
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• 2010

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we proposed a simplified presumption method for the prediction of cooling and heating performance in the system. In conclusion the proposed method has been verified by comparing with the calculated value of the numerical analysis model by using nonlinear two-dimension hygroscopic question.

• Journal of the Korean Society of Industry Convergence
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• v.13 no.3
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• pp.169-181
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• 2010

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we proposed a simplified presumption method for the prediction of cooling and heating performance in the system. In conclusion the proposed method has been verified by comparing with the calculated value of the numerical analysis model by using nonlinear two-dimension hygroscopic question.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.11
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• pp.1092-1100
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• 2004

This paper presents the effect of opening configuration on the thermal behavior and air pattern of earth tube system. The earth tube system is a fresh air load reduction system by using underground double floor space for air-conditioning. In order to analyze the effect of opening configuration on thermal performance of this system and air pattern in underground double floor space quantitatively, we used a model dealing with tree-dimensional profile of wind velocity and temperature in underground double floor space. In conclusion, it is confirmed that heat exchange of a fresh air is mainly performed with upper and lower wall in underground double floor space, and that heat exchange area increased by installing the opening near the wall.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.3
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• pp.233-240
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• 2004

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space The system was introduced into a real building and was examined by the field measurement Judging from the measurements during three years(1999~2001), the state of the system operation was very stable through this period and it was clear that the system contributes to reduction of energy consumption for air-conditioning. Futhermore, a simulation model used the simple heat diffusion equation Was developed to simulate its thermal characteristics and performances The simulations resulted m air temperature in good agreement with the measurements. Also, from the result of numerical analysis, It is clear that the amount of heat supply by using this system is more than the amount of energy loss to the room above it. Therefore, it is concluded that this systems is very useful and the proposed numerical model can be used for the prediction of system thermal performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.2
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• pp.116-125
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• 2003

The new HVAC system to lower the conveyance energy and building height using IAV (Increasing Air Volume) technique is developed. IAV units which are equipped in each zone carry out air-conditioning and supply fresh air by induction of outdoor air in main duct. The design program which decides size of OAHU and IAV unit according to air conditioning load and fresh air demand of each zone is presented. The control system is developed to operate efficiently HVAC system and IAV unit, so that individual zone operation and well-deal with partial load and IAQ problem are possible. The new system is investigated in model building and makes more profit in conveyance energy, size of air conditioning facilities room and building height than VAV system. But in construction cost it is worse by about 15 per-centage.

• International Journal of Air-Conditioning and Refrigeration
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• v.13 no.1
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• pp.31-43
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• 2005

The new HVAC system is developed to lower the conveyance energy and building height using IAV(Increasing Air Volume) technique. IAV units which are equipped in each zone carry out air-conditioning and supply fresh air by induction of outdoor air in main duct. The design program which decides size of OAHU and IAV unit according to air conditioning load and fresh air demand of each zone is presented. The control system is developed to operate efficiently HVAC system and IAV unit, so that individual zone operation and well-deal with partial load and IAQ problem are possible. The new system is investigated in model building and makes more profit in conveyance energy. size of air conditioning facilities room and building height than VAV system. But in construction cost it is worse by about 15 percentage.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.21-28
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• 2006

Changes in building construction methods and repairing of older buildings have reduced infiltration rate. Synthetic materials, release airborne particles and uneven healthy odor are increased. For preventing pollutants introduce fresh outdoor air into the building, simply letting fresh outdoor air into building, however, Is not a cost-effective way to ventilation. When additional ventilation is added to an existing HVAC system, the heating and cooling equipment, often cannot handle the increased load. A HRV provides a way to minimize in energy costs while introducing fresh air to a building. In this study, the economical research of HRV, made of three types of materials, are conducted. Heat recovering characteristics are studied at seasonal outdoor air conditions based on the outdoor air property condition at, Seoul in 2002. As a results, the average sensible effectiveness is 0.75 in the sensible heat exchanger and average total effectiveness is 0.65 in the total heat exchanger. The pay back period of the sensible heat exchangers are $3.2{\sim}3.5$ year and it of total heat exchanger is 2.2 years.