This paper presents a simplified method of estimating seasonal air-conditioning loads in office buildings. The method is based upon precise computer simulations using a computer program HASP/ACLD/7301 together with a standard meteorological data for Osaka HASP/ACLD/7501. Outline of this method is as follows. Usually air-conditioning loads are composed of several parts and each component is considered to have a paticular feature and may be specified by some characteristic quantities x_m(m=1,2,…) determined from building materials and their thermal properties. Firstly x_m(m=1,2,…) are selected for one of the load components, then seasonal load Q_i of the component is calculated for given values of x_m using the computer program, assuming that only one load component exists in a reference room. Through these calculations, a curve representing the relations between Q_i and x_m is determined. Similar procedure is repeated for other load components. Thus the curves prescribing Q_i v.s. x_m relations are prepared for all load components. Users may utilize these curves directly and can estimate resultant seasonal loads easily. According to some examples applied to model spaces estimated values show fairly good agreements with computer simulations.

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Generally, Uniform Flow Ventilation means ventilation applied slow, wide, and unidirect air flow, and can also be divided into several classes. In this report, it is classified as follows. Uniform flow ventilation; (1) Perfect uniform flow ventilation (Perfect piston flow ventilation) (2) Imperfect uniform flow ventilation 1) Ventilation by piston flow in each part 2) Ventilation consisting of piston flow and dilution parts 3) Ventilation consisting of piston flow and stagnant parts Then, each characteristic of the ventilation model above is researched, paying attention to the stream lines in the ventilating room. Adoption a newly defined ventilation efficiency, K, on the uniform flow ventilation seems to be effective because of its different characteristics from the conventional dilution ventilation. Thereupon, K is defined by the following equation K=(Q_G/Q)/C_k (in the constant condition). where, Q_G: generation volume of tracer gas Q: ventilation flow volume C_k: concentration of tracer gas in the room

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The heat transfer characteristics of an in-line tube bank, whose tubes were settled in horizontally, were studied in the cross flow of water and transformer oil at a low Reynolds number. The Reynolds number Re based on the velocity u_t of the minimum flow area and the tube diameter d ranged from 20 to 2500. The spacing of the tubes (c_y/d×c_x/d, where, c_y, c_x denote the transversal pitch and longitudinal one, respectively) was as follows: 1.7×1.3, 1.7×2.6, 3.4×1.3, 3.4×2.6. It was found that the local heat transfer ratio in the rear face of the tubes in the back row of banks was not affected by the Reynolds number in the laminar flow field (Re&lsim;100). The heat transfer distributions around the tubes in the bank were not symmetric in the transversal direction of flow due to the natural convection effect, especially, at the low Reynolds number. It was evident that the mean Nusselt number Nu_m did not vary with the Reynolds number as against the previous experimental data in the range of Re<40. Also, the variation of Nu_m in the difference of the spacing was not especially large.

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SIMPLE (Semi-implicit Method for Pressure-Linked Equations), which was presented by Patankar and Spalding in 1972, is a very economical numerical calculation method for predicting three dimensional flow fields where a dominant flow direction exists. In Parts 5 and 6 of this study, the authors showed that SIMPLE was available for predicting the behaviour of warm water discharged into a rectangular open channel. However, some problems were also pointed out. One of them is that when warm water is discharged with very strong buoyancy, or is discharged near the surface of the channel water and a stable thermally stratified flow is formed, discrepancies between the computed results and experimental results appear in the reduction of the maximum temperature in the main flow direction and thermal distributions near the water surface. To solve this problem, first, it is necessary to take as fine as possible mesh intervals and diminish the influence of the apparent viscosity accompanied with upwind differencing. If fine mesh intervals are taken in the depth direction, however, the mesh intervals in the main flow direction must also be made very fine to hold the stability of calculation. Therefore, the largest merit of SIMPLE, that is, that it is economical, decreases. It is assumed that the instability of calculation is mainly caused by the following two factors: one is that the coefficients of finite differences equations for momentum equations are approximated by the values calculated with upstream velocity, temperature, and viscosity. The other is that several terms of Poisson's equation for pressure are neglected for brevity. The purpose of this paper is to improve the stability of calculation of SIMPLE and to save computation time by evaluating the coefficients in the finite differences equations correctly with downstream information and including the terms neglected in Patankar's SIMPLE. Taking these two points into account, an iterative calculation is necessary to solve the finite differences equations for the velocity and the Poisson's equation for pressure because the coefficients and the terms neglected in Patankar's SIMPLE are unknown values which are obtained with downstream information. As this point is different from Patankar's SIMPLE, the authors name the method presented in the paper "iterative SIMPLE". To discuss the performance of Patankar's SIMPLE and iterative SIMPLE, computations with both methods and an experiment on the behaviour of warm water were carried out under the condition that the warm water was discharged near the water surface of a rectangular open channel from a rectangular conduit in the center of the channel. The results of the computations and experiment clearly show that the stability of calculation and computation time of iterative SIMPLE is superior to those of Patankar's SIMPLE. A new convenient differences scheme in which we can choose at will an upwind differencing scheme (UDS), centered differences scheme (CDS), or hybrid differences scheme (HDS) by changing the value of a positive coefficient m: m=0 then UDS, m=∞ then CDS, and 0<m<∞ then HDS is also presented.

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The two-dimensional flow fields in the pipe junctions with roundness at the upstream edge and the upstream and downstream edges of the lateral entrance in the turbulent flow were solved numerically by using the k-ε turbulence model. The mean flow in the real pipe junctions was observed by means of a flow visualization technique. The computed results referred to the mean flow were compared with the experimental ones.

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It has been recently recognized how important it is to improve living environment in a building and save fossil energy by utilizing natural energy resources and natural environment. Since we need both heating and cooling in this country, it is necessary to investigate the possibility of passive cooling in summer as well as passive heating in winter. From this point of view, this paper takes up evaporative cooling by means of roof spraying as a technique of passive cooling, and passive cooling effect is studied on a model building roof sprayed with water and naturally ventilated by temperature differences and wind forces. First, this paper describes the calculation method of room temperature, humidity and air pressure in a building, which is roof sprayed and naturally ventilated by temperature differences and wind forces. Secondly, room temperature, humidity and air pressure are simulated for a model factory according to the above-mentioned calculation method, varying the conditions of heat insulation grade and the rate of internal heat generation, with the aid of meteorological data of the Tokyo area in summer. The seasonal frequency of room temperature, humidity and environmental temperature is analyzed by comparing it with the results obtained from "without roof spraying", followed by a discussion on combined passive cooling effects of roof spraying and natural ventilation as well as improvements on the inner thermal environment of the building.

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As one of the means for energy saving and environment preservation, a regionally concentrated air-conditioning system using chilled or hot water as a thermal media has recently been reconsidered. And an thermal energy meter has been developed. For the flow measuring element of semimicro meters, tangential rotor wheel type is widely used. Various experimental results of this flowmeter are considered, the following defects are evident: 1) At heating, because bubbles mixed in circulating hot water are retaind over a long time in the casing of rotor wheel, the measuring error remarkably increases. 2) By the frictional resistance of mechanical moving parts, the measuring error occurs in a lower flow rate range. 3) A change in the viscosity of fluid gives a bad influence on the measuring performance. In order to improve the above defects, a new flowmeter using a fluidic oscillator has been built trially for proposal. In addition, the observations for the optimum desgin conditions of the flow path shapes, and the various performances are described. The flowmeter is constructed by both main piping system that is equipped with an orifice and bypass piping system constituted by a feedback fluidic oscillator. This fluidic flowmeter is attached on inside walls near the inlet of feedback duct, unlike the conventional flow path. By the consideration from various experimental results, the following are evident: 1) The measuring error due to the stagnation-accumlation phenomenon can be eliminated. 2) The pressure loss is very little, and this meter is small in size, light in weight and simple in construction. 3) Considering various characteristics of the flow path shapes, the following are evident: a) The optimum position of the inside wall is as follows; each distance from the main nozzle or attachment wall are 13〜20 or 1.5〜2.5 multiplied by the main nozzle width. And the oscillating phenomenon is stable in the lower flow rate range. b) The detecting gain increases proportionally to the distance of the inside wall from the main nozzle. 4) For the oscillating characteristics of the flowmeter, the following are evident: a) The oscillating frequency does not influence very much on the changes of viscosity and density for 20〜75℃. b) The oscillating frequency increases linealy in the wide range, and the measuring accuracy is about ±2% to flow rate of 0.15〜2.2m^8/h. Summarizing the results of the present experiments, it is evident the fluidic flowmeter trially made is very usefull for the flow measuring part of the thermal energy meter. And, the fluidic flowmeter has better performance as compared with previous flowmeter.

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In the previous paper, the authors reported on the behavior of the thermally stratified layer under belt-driven circulation in the top layer of rectangular water tanks, and showed that the descent velocity of the stratified layer was determined by the densimetric Froude number. This paper clarifies the behavior of the stratified layer under wind-induced circulation in the top layer of a rectangular water tank. Wind-induced circulation has three main features; the first is that the water surface stagnates near the leeward wall of the water tank and the water surface is not driven uniformly; the second is that the densimetric Froude number increases with time owing to the heat loss from the water surface; the third is that the descent velocity of the stratified layer was not constant during the experiments but increases with time. However, the flow in the rectangular water tank is similar to that of the belt-driven circulation reported in the previous paper. It is clear that the descent velocity of the thermally stratified layer is determined by the densimetric Froude number and that the relation between the descent velocity and densimetric Froude number is expressed by an equation similar to that of belt-driven circulation. Prediction of the top layer temperature and the depth of the stratified layer was also tried with a simple model for the heat budget of the top layer and the equation for the descent velocity of the stratified layer. The predicted values agreed well with the experimental values.

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