In this paper, the thermal performance of a sunspace attached to a house with a central air conditioning system was experimentally investigated. The house with a south-facing sunspace is located in Miyazaki, Japan, where heating is required in winter. In order to reduce the heating energy in winter, the hot air from the attached sunspace is sent to the central air conditioning room, from where it is then distributed and stored throughout the house by way of air circulation. Only when the temperature in the sunspace exceeds 24 • C is the hot air in the sunspace sent to the central air conditioning room. The air circulation between the attached sunspace and central air conditioning room is 500 m 3 /h. The temperature of the attached sunspace and each room were measured. The results showed that a house with a sunspace can save about 12.2% of energy compared to a house without a sunspace.

Recently, the fight against global warming is becoming increasingly important. Being major energy consumers, air-conditioning (AC) loads are gaining importance. Therefore, the effects of heat insulation methods and AC usage patterns on AC loads should be verified before a building is constructed.This paper examines the AC loads of two typical residential units of steel (S) and reinforced concrete (RC). To compare and analyze these cases, THERB, software for dynamic simulation of the thermal environment of residential buildings, is employed to simulate the loads.Three common patterns based on the lifestyle in Japan are applied in this study to show that different family makeup can lead to varying AC loads. Further, two RC units (exterior wall insulated on the inside/ outside) and one S unit (exterior wall insulated on the inside) are studied. The results reveal that the high heat capacity of concrete influences the living environment and causes differences between the RC and S units. The AC load of an RC unit with an exterior wall that is insulated on the inside is lower than that of a unit with an exterior wall that is insulated on the outside and is almost equal to that of the S unit.

Based on numerical simulations, the heating load reduction effect of an attached sunspace in winter was determined, and the effective heat utilization method and sunspace design were explored. In this paper, we studied the heating load reduction effect using heat from the sunspace and temperature fluctuation of each room at the time of heat use from the sunspace (sending air from the sunspace to the heating, ventilation, and air conditioning (HVAC) machine room and taking the air to the adjacent rooms). In the case of the all-day HVAC system, it was confirmed that a larger capacity of sunspace and not sending air from the sunspace to the adjacent room demonstrated a better heating-load reduction effect. Compared with Model Iw (a house with a window on the exterior of the sunspace opened to external air), Model I (a house with an attached sunspace on the second floor) could save approximately 41% of the total energy. Model II (a house with the attached sunspace both on the first and second floors) could save approximately 84% of the total energy. Sending heat from the sunspace to the adjacent room led to temperature increases in the adjacent rooms. However, if the construction plan is to have the sunspace only on the second floor, the house should be carefully designed, for example, by placing a living room on the second floor.

In this paper, the influence of moisture sorption and desorption of walls on space conditioning load is evaluated by dynamic simulation based on detailed building physics taking account of heat and moisture transfer and airflow of whole buildings. Then sensitive analysis is performed with a number of factors, such as preset temperature and humidity of space conditioning, ventilation amount, property of interior materials and so on, which influence indoor humidity. Eleven factors that affect indoor humidity are defined with the extent of the influence by the multiple regression analysis on the basis of the sensitive analysis. It is clarified that the moisture sorption and desorption of walls are influence both heating and cooling load at a rate over 10 percent and water vapour permeance and moisture capacity of interior finish are the significant factor on the moisture sorption and desorption.

No abstract