This paper is the second report of a series of research on a passive type hydrogen storage system with hydrogen absorbing alloys for two purposes. [1] It aims to improve hydrogen absorption and desorption characteristics of the system by using MmNi_5 as a higher equilibrium pressure alloy and containers with fins or small diameter tube type containers that are enlarged the surface area of the containers per MmNi_5 weight. [2] It also aims to investigate possible introduction of the hydrogen system for independent power supply or residential energy system. Both the containers with fins for independent power supply and the small diameter tube type containers for residential energy system are practical from a viewpoint of the hydrogen absorption-desorption flow rate and the total hydrogen storage capacity.

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In this paper, based on the multi-objective optimization approach, a renewal planning method is proposed for an air-conditioning system, by which the optimal renewal system can be determined by selecting the optimal renewal year and the system's structure from both economic and environmental viewpoints simultaneously. In this method, one objective function is the average annual total cost of the system, which is the summation of the annual capital, operational and maintenance costs based on the annualized cost method during the evaluation years. The other objective function is the average annual total amount of CO_2 emission during the evaluation years. The numerical optimal solution is derived for the system of an office building by the mixed-integer linear programming algorithm together with the ε-constraint method. As a result, the set of Pareto optimal solutions is derived, and the trade-off relationship between economy and environment is analyzed. Through the result of the set of Pareto optimal solutions, tolerating the increase of the average system's annual total cost up to 1%, we can reduce the average amount of CO_2 emission from the system up to 15%. One another main result obtained shows that it is necessary to introduce electrically-driven heat pump to reduce CO_2 emission.

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The thermal storage system in a building's HVAC system theoretically exemplifies the technological advances of energy conservation as well as reduction of CO_2 emissions. It has been reported, however, that energy conservation is not achieved in actual operation due to non-optimal system operation. To solve this problem, the authors previously proposed a basic methodology for optimum operation of a thermal storage water system based on simulation technology and thermal load prediction. Also, the effect of optimum operation by simulation was shown in simulation basis. In this methodology, the setpoint temperature of the chiller, θ_<set>, and chiller operating time at night, t_<ope> to minimize the total system energy consumption are determined based on the based on simulation technology and thermal load prediction. However, the dehumidification performance of the cooling coil deteriorates and thermal environment in the room may become worse when θ_<set> is higher. In the present paper, the optimum operation scheme considering the dehumidification performance is developed to prevent such defect. Also, the effect of the scheme is shown in simulation basis.

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Static pressure drop-air flow rate characteristics data of air terminal devices and branches are measured and analysed by using the proposal measurement methods, which is described in the previous paper written by the authors. The proposal measurement methods are validated by using the results of the consistency between "the static pressure distribution method" and "the duct's static pressure correction method" or the investigation of the correction method between the existing measurement protocols and proposal measurement methods. Moreover, whole ventilation system's pressure drop and air flow distribution on each air terminal devices, which are calculated by theoretical calculation, are validated with the ventilation components' static pressure drop-air flow rate characteristics data measured by the proposal protocols. The result shows that the calculated value is accordance with the measured value. Therefore, the usefulness of the proposal measurement protocols and the calculation method using static pressure for designing of domestic ventilation systems are confirmed.

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