In a subway where traffic volume is small, there is a possibility of keeping the air temperature in summer by optimizing mechanical ventilation schedule to utilize heat sink effect of the ground. In the first part of this paper, the optimum ventilation schedule and maximum traffic rate in subway system that maintains air temperature in a platform at comfortable levels without cooling were examined by computer simulation which developed in the previous paper. In this paper, two representative ventilation systems, i.e., 'platform supply-tunnel exhaust system' and 'longitudinal ventilation system' are simulated. Secondary, the heat sink effect of the ground in the platform was analyzed quantitatively. Heat sink effect was classified into following three elements. The first is the heat conduction from platform to ground surface. The second is the annual and daily cycle cold heat storage of the ground. The third is the cool tube effect of the adjacent tunnels. As the result of this analysis, it was seen that the cool tube effect was largest among these elements and annual cycle cold heat storage effect was almost as large as daily cycle cold heat storage.

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A model piping system with two branch pipes was constructed, and four valves were operated simultaneously. The dynamic flow characteristics inside pipe were theoretically obtained by calculation of the kinetic equation and continuous equation in using the characteristic curve. The dynamic demand load in this model was evaluated by information entropy. The authors analysed the influence of the piping condition and the different in time of each fixture usage. The following results were obtained. 1) Two parametric maximum entropy distribution was useful method to analyse the current flow in water supply pipe system. 2) The value of maximal entropy was large in small radius pipe, and under high pressure, but the length of pipe was not affected.

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Automatic fault detection and diagnosis (FDD) is an important process which has been ignored but has great effect to realize energy conservation in building services engineering systems. Present paper introduces a trial of FDD in the thermal storage control system by the pattern recognition method. It has been recognized that the temperature profile is a proper index of the thermal storage system performance. Mapping process based on the statistical theory with significant parameters derived from the Fourier Analysis of the temperature profiles showed a high performance of FDD for the two kinds of control faults using fault simulation data.

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An operational problem, in which the operational strategy is determined so as to minimize the daily operational cost, is discussed for energy supply systems including thermal storage tanks. By considering on/off status and operational modes of equipment as well as energy flow rates and storage levels, as operational strategy, and by discretizing a day into multiple periods, this optimization problem is formulated as a large-scale mixed-integer linear programming (MILP) one with a number of unknown integer and continuous variables. Therefore, it is difficult to solve it in a practical computation time by means of the branch and bound method used conventionally. In this study, an approximate method is proposed to solve it efficiently from the viewpoint of computation time. The proposed method is of two-level hierarchical structure which consists of decomposition and coordination levels. At the decomposition level, the operational strategy is analyzed separately for each period without coupling constraints due to dynamical relationships of thermal storage, and incremental/decremental costs required to charge/discharge thermal storage tanks are calculated. At the coordination level, the daily operational strategy of thermal storage tanks is derived by considering the coupling constraints and by adopting the objective function in terms of the incremental and decremental costs. A numerical study is carried out for a district heating and cooling system to ascertain the effectiveness of the proposed method. Through the study, the proposed method has been compared with a decomposition method for MILP problems, and the following main results have been obtained here. 1) The proposed method enables easy and rational determination of the operational strategy for energy supply systems including thermal storage tanks. 2) The difference is small between the daily operational costs determined by the proposed method and the decomposition one. 3) The Proposed method can reduce the computation time drastically, compared with the decomposition one.

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In order to provide basic data for the museum air-conditioning system and energy conservation design, this paper presents an analysis of the measurements over a one-year period of the actual performance of a museum air-conditioning system. In spite of the fact that the museum is situated in a relatively cold area, two air source heat pumps cooperating with a stratified-type heat storage water tank were adopted as heat source. A water source heat pump was also installed for the simultaneous occurrence of cooling and heating loads due to dehumidification or room temperature adjustments in the storehouses and exhibition rooms. A monthly analysis of the annual energy production showed that 82.4% of the amount of hot heat produced by this system and 87.4% of the amount of cold heat were sent to the secondary side, with 57.7% of the amounts of cold and hot heat consumed by the storehouses and the exhibition rooms. The COP of the air source heat pumps was 3.1〜3.3 for chilled water production, and 2.3〜3.2, normally, for hot water production, and declined by 20% during defrosting operation. The COP of the water source heat pump was 3.4〜4.4 on the hot water side and 2.4〜3.0 on the chilled water side. The heat storage tank effective volume rate was 58.6% in winter and 76.2% in summer. Furthermore, the annual system COP was 2.45.

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This paper describes the model experiment using a concrete panel in which an electric heater was set. The panel was put on the soil in a box which is set in a constant temperature chamber. The conditions of air temperature of each point in the set was measured. This experiment was modeled as one-dimension thermal conduction in the steady state, and analysed theoretically about effect of insulation and water content of soil. Furthermore effect of side walls and three points of the heater was evaluated by two-dimension thermal conduction model in the steady state. The results can be applicable to the modeling of actual conditions.

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The characteristics of natural convective heat transfer on a vertical heated plate with a single square solid element was numerically and experimentally examined. Experiment was optically performed by using Mach-Zehnder interferometer. A solid element tends to make the thermal boundary layer increase. As the results, the local heat transfer is depressed, and from the reattachment point it is improved along the wake of a solid element. When a space exists between the heated plate and a solid element, the flow is accelerated and the local heat transfer is remarkably improved. The effect of thermal conductivity of a solid element is also examined. These results give us basic data on a location of a solid element in a room with air-conditioning system.

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The temperature selective heat storage tank (TSHST) was proposed and the TSHS model to calculate temperature distributions in the TSHST was shown in a series of previous papers. It turned out to be possible to design the TSHST and to predict its temperature characteristics. In this paper, further improvements are made for the TSHS model to design the TSHST more suitably. Comparing with the results of the previous paper, better agreements are obtained between the measured and the calculated temperature distributions. Based on the difference between the ideal and the real temperature distributions, an index ε that evaluates the temperature selectivity is defined. The ε varies from zero that reveals a perfect mixing tank to the unity that reveals an ideal TSHST. Calculations of the ε are conducted by changing various factors. It is found that dominating factors which influence the ε of the subtank are cross sectional mean velocity and its aperture area. The ε of the TSHST depends on that of the subtank and the cross sectional area ratio of the subtank to the main tank. Finally, an optimum design method of the subtank is shown as the ε gives a maximum value.

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The use of a road snow melting system that is one of the way to solve snow problems increases energy consumption and is not desirable in the aspect of global environmental issues. Though it is usually used only 4-months in winter, if it could be used as a solar water heater outside of the winter season, the total energy efficiency will be improved. In this paper, a suitable roadbed structure for solar collecting is the examined by experiments and numerical simulations in order to develop such the system. The results are as follows. 1) The results of calculation for solar collecting corresponded to the results of measurement within 10% error. 2) The use of insulation under the pipes is effective for solar collecting. 3) The thickness of insulation doesn't affect the performance of solar collecting excessively. 4) The thickness of pavement on the pipes is desired to be thinner compared with the general roadbed structure for snow melting.

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There are few reports on the sound insulation efficiency of ducts, and the effect of the duct shape on Sound Transmission characteristics has been scarcely investigated in Japan. Therefore, we examined the measuring methods of the transmission loss (TL) through the duct walls, then we measured the TL for the various shaped ducts to investigate the TL chracteristics of no lugging ducts with rectangular and circular shapes. The measurements were made both directions (breakout and breakin of the sound energy) of propagation through the duct walls. As a result of these experiments, the followings were found: 1) To measure the TL of ducts, the hemi-free field method or the SI method should be applied. 2) For no lugging rectangular type ducts, TL values obtained from the prediction formulas by ASHRAE were similar to our experimental data, therefore the formulas are effective. 3) Duct with a perfectly circular cross-section have a very high TL at low frequencies, however by decrease of the impedance for the cross sectional direction, the TL of the distorted circular ducts are effected considerably.

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