This paper describes a performance evaluation of CO_2 heat pump (HP) water heaters. We evaluated the influence of reheating operation and domestic hot water (DHW) load characteristics on the system performance. First, we carried out experiments by using the modified M1 mode for the DHW and reheating loads. The great differences about the control of the output hot water temperature of the HP unit, and the amount of hot water storage etc. are confirmed under the reheating operation compared with results of the modified M1 mode only. In the reheating operation, SCOP is lower than the value for the modified M1 mode by approximately 30% in winter. Secondly the Hot water whose amount of heat was equivalent to the reheating load was taken in a bathtub. Although differences in operation control compared to the modified M1 mode were not detected, the hot water supply temperature fell below 60°C several times. Within around 40% decrease or increase compared with the standard hot water usage, there were almost no differences on the operation control. SCOP at the lower hot water load fell below the standard. Therefore, it is necessary to consider a DHW usage model appropriate for the amount of a DHW load.

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The purpose of this study was to clarify the regional characteristics of the heating load of detached houses in China. First, typical meteorological year data for 360 Chinese locations (CHINA-TMY2) were developed using observational weather data for the period of 1995 〜 2005. Then, a detached house model was considered, and the heating load for four different types of heat insulations was calculated for the 360 Chinese locations by using the CHINA-TMY2. Maps for the heating load of detached houses were created for different types of heat insulations. On the basis of simulation results, an equation was established with parameters such as heating degree-days, solar radiation in the heating period, heat loss coefficient, and solar gain ratio, for estimating the heating load. With this equation, the heating load of detached houses can be predicted for different types of heat insulations at any location.

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Indoor environments in large-scale commercial buildings are managed under the "Law for Maintenance of Sanitation in Buildings" (enacted in 1970) in Japan. The law applies to specific buildings such as offices, stores, entertainment facilities, assembly halls, libraries, museums, and schools, and it establishes environmental standards for carbon dioxide concentration, airborne particulates, carbon monoxide, formaldehyde, room temperature, relative humidity, and air velocity for controlling indoor climate. This study was aimed at examining the actual status of environmental sanitation and building maintenance by referring to the nationwide on-site building inspection database developed by the Japanese Government. We analyzed data from 1996 through 2008. The carbon dioxide concentration, room temperature, and relative humidity were found to increase by a small amount every year, especially in office and school buildings. The reasons for the tendencies could be the revision of the Law in 2002, which excessively encouraged energy saving measures in buildings.

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We aimed to examine a method for maintaining a sanitary and healthy air environment at welfare facilities for the aged. Four welfare facilities were considered for summer and two facilities were considered for winter. The seven parameters influencing the indoor air quality, namely, air temperature, relative humidity, air flow rate (velocity), and carbon monoxide, carbon dioxide, particulate matter, and microbial concentrations, were measured in accordance with the legal and academic standard method. The results were as follows: (1) It was clear that the temperatures inside the rooms were quite high in summer and the relative humidity inside the rooms was quite low in winter. (2) The carbon dioxide concentration increased considerably when the population density inside the room became very high. (3) The microbial concentration was quite high in almost all the facilities and rooms. It appeared that the filters installed in the ventilation systems influenced the microbial concentration. (4) It is important for the HVAC system designer to grasp the actual operating conditions of the welfare facilities for aged and adopt the most appropriate HVAC system.

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The transport routes of contaminants from outdoors to indoors through the ventilation system have been recognized as dominant pathways. These contaminants originating outdoors may deteriorate the indoor air quality level and adversely affect on human health. In order to prevent particulate matter contamination of indoor environments, the control of the transport of particles from outdoors to indoors through ventilators is important, and the use of a vertical ventilator is one of the effective methods to prevent the transport. In this paper (Part 1), visualization measurement was performed by using a PIV system to measure airflow in a vertical ventilator model. Images of smoke structures were recorded and processed to provide detailed validation data for CFD simulations. Furthermore, CFD simulation by using three types of turbulence models, Low Re type k-ε model, RNG k-ε model and SST k-ω model, and by considering same geometry and boundary conditions for the experimental vertical duct model were carried out. The difference between the peak velocity values measured with the PIV system and CFD was approximately 10 %.

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