This paper is the Part 2 on the performance evaluation of a fume hood under realistic use environmental condition following the Part 1. In the Part 1 study, we conducted integrated computational fluid dynamics (CFD) and computer simulated person (CSP) analyses as functions of the frontal opening area and indoor environmental conditions of a laboratory, and clarified that the inappropriate exhaust outlet air flow conditions, e.g., extremely low velocity at the apertural area, had an impact on the contaminant capture efficiency in a fume hood. In Part 2, we numerically investigated the protection performance of a fume hood by analyzing the index for ventilation efficiencies, e.g., local purging flow rate (L-PFR), net escape velocity (NEV), and age of air (SVE3). The presence of a worker in front of a fume hood has a certain impact on the air velocity distributions at the apertural area of a fume hood. Furthermore, it was also confirmed that the presence of a worker has a great influence on the flow field and contaminant concentration distributions inside the fume hood. In this paper, we reproduce the state where a part of the user’s arm is inserted inside the fume hood and evaluate the performance of the fume hood assuming a more realistic environment. In addition, we analyze the performance of the fume hood using several ventilation efficiency indexes (NEV, SVE3, L-PFR) in order to quantitatively understand the structure of the pollutant concentration distribution formed in the fume hood.

To use energy efficiently, we investigated an air-conditioning system for storing geothermal heat in a building structure. In summer, for exchanging heat between the ground and the building structure, the solar load stored in the building mass was removed and the heat transfer to the rooms was suppressed. Thus, we could verify that exchanging heat between the ground and the building structure was possible because the energy efficiency was higher owing to the large thermal difference. Moreover, the heat radiation from the building structure allowed the formation of comfortable thermal environment in the rooms.

This study proposes a hybrid drainage system, by employing a combination of a “force-feed drainage system” (that comprises a force-feed pump unit and small-diameter force-feed pipes) and a “gravity drainage horizontal pipe system” (in which drainage flows by gravity). This system ensures good drainage even when plumbing modifications or extensions are carried out because of the conversion or renewal of newly built or existing office buildings. The study also aims to evaluate the performance of the proposed system, thereby facilitating the effective the design of the system. Among the various types of hybrid drainage systems mentioned in the initial report1), this report focuses particularly on the “system using existing horizontal fixture branch”, in which existing horizontal fixture branch in a building are used and drainage is pumped up from the downstairs by the force-feed drainage system. This study also determines the basic drainage performance of its system with the aim of collecting data.

There has been an increase in the use of desiccant air-conditioning systems for handling latent heat loads in latent and sensible heat separation air-conditioning systems that allow energy saving without affecting the comfort and reducing the productivity of office workers. However, desiccant air-conditioning systems require a flow path for regenerating the desiccant in addition to the flow path on the processing side, which increases the conveyance power of the air system compared to that of a general air-conditioning system. In this study, with the aim of reducing the conveyance power of desiccant air-conditioning systems, we investigate an approach for reducing the air system conveyance power by controlling the air supply fan and regeneration fan in the system according to the demands in the rainy season and under summer and intermediate climatic conditions. In addition, by verifying the indoor thermal environment, we examined the effect of applying demand control on the performance of the desiccant air-conditioning system, and obtained the following findings. 1) The reduction rate of the total power consumption of the air-supply fan and the regeneration fan with respect to the set power consumption at the standard air volume was confirmed to be 21.5%-63.3% in the rainy season, 3.8%-55.7% in summer, and 25.6%-73.1% in the intermediate period. 2) The energy saving effect of demand control was confirmed to be stronger in the rainy season and the intermediate period than that in the summer, during which the outdoor air load is maximum. In this report, we examined the possibility of improving the energy saving performance based on the results of the experiments performed on the representative days of each season. In future, we plan to evaluate continuous operation by applying to actual properties.