In an air-conditioned room where perimeter heating and interior cooling are applied simultaneously, heat loss (mixing energy loss) often occurs mainly because of the mixing of heated and cooled air jets. The purpose of the presnt study is to clarify the qualitative and quantitative mechanism of such loss and establish preventive measures for it. Firstly in this paper, experiments were performed with actual sized equipment by utilizing the "design of experiments" method, and the degrees of effects by these factors having significant influence on the mixing loss were explained by the analysis of variance. The main results obtained are; 1) The control temperature difference between the perimeter and the interior has the greatest influence. The lower the control temperature of the former is, the less the mixing loss is. 2) In order to diminish energy loss under the restraint of room environment, it is effective to use panel-heating together with air or water system (e.g. fan-coil unit) in the perimeter.

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It is a serious subject for energy conservation to prevent the energy loss caused by the mixing of heated and cooled air jets in a building where different air-conditioning systems are applied in the perimeter and interior zones. In Part 1, the authors disclosed factors which had significant influences on the energy loss quantitatively by experiments with actual sized equipment, and based on those results, proposed the air-conditioning system and the operating condition effectual for prevention of the mixing loss. In this paper, the estimation equation of the amount of the mixing loss was proposed by the multiple regression analysis of all experimental results described in the previous paper as follows: MLR=31.281SPD+0.053FCH+2.469IACR-29.157 where MLR: ratio of mixing energy loss to sum of perimeter heating load and interior cooling load [%] SPD: control temperature difference between perimeter and interior zones (the latter from the former) [℃] FCH: heating load supplied by perimeter warm air jet [kcal/m・h (width of exterior wall)] IACR: air change rate in interior zone [h^<-1>] This equation can explain about 73% of the complicated phenomenon, therefore, it seems to be accurate enough for practical use. Furthermore, several estimations of the seasonal energy loss were performed for a typical office building using the dynamic heat load calculation and the above equation. According to the simulations, the effects of various operating conditions on total energy loss in the building overall in winter were clarified.

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Dividing flows at 90deg equal area branches consisting of rectangular sectioned duct with aspect ratios of 1/4 to 4 were studied in our previous experiments. And the observations on the flow developments in both main and lateral duct were also carried out. Because the dividing flows in the fluid branch system are very complicated, we have to use a simple flow model for the simulation of such dividing flow as mentioned above. At first, the dividing flow in the lower parts of the main or lateral duct was substituted for the flow in a straight duct without branch. And then, the unsymmetric velocity distribution, which is considered to correspond to that of the real dividing flow, was set to the flow at the inlet of the duct. The three-dimensional laminar flows in the duct based on the above model were analyzed numerically by use of the same method as Patankar's. By the computed results on the flow at the lower parts of the ducts, the dependency of the velocity components in each directions on the distance along the duct were studied. And, the relations between the aspect ratios and the distances required for the flow developments were also studied.

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In former studies on push-pull flows, experimental investigations of the push-pull flows have been undertaken under the limited conditions. In this paper, the flows of various conditions are investigated by applying a method of numerical calculation to the push-pull flows. Assuming that the push-pull flow is two-dimensional, laminar and isothermal, and using stream function and vorticity for dependent variables on the equation of motion, we can obtain a model on the push-pull flows and solve the following three problems simultaneously. 1) Limit flow ratio of the push-pull flows when a disturbing flow does not exist 2) Inflection of the push-pull flows when a disturbing flow exists 3) Effect of a flange equipped on an opening of push flow In addition, we make experiments to determine whether the results of numerical calculation are correct or not, and compare the measuring values or visualization of stream with the results of calculation. Consequently, the results of calculation are in approximate agreement with the experiments. From the facts described above, we may conclude that the numerical calculation is an effective method for the study on the push-pull flows.

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In the calculation of heat loss through exterior walls from a heated room, a set of simultaneous equations must be solved to obtain the exact heat loss because of the presence of radiative heat transfer among the interior surfaces. However, in many practical calculations, instead of solving the simultaneous equations, equivalent thermal conductances between room air and the interior surfaces are used to calculate the thermal loss. In this approximate method, the heat balance equation for each wall can be solved independently. The equivalent thermal conductances are given by adding the radiative heat transfer coefficients to the convective ones. Conventionally the value of 4〜5[kcal/m^2・h・K] is used as the mean radiative heat transfer coefficient. However, this value makes serious errors in estimating heat losses under certain conditions. In this paper, the exact mean radiative heat transfer coefficient is defined as the one which gives the same total heat loss through the exterior walls as that obtained by solving the rigorous simultaneous equations. It is shown that the exact mean radiative heat transfer coefficient changes greatly according to the changes of many factors. In order to clarify the fundamental of the change, a simple room model composed of only 2 surfaces is used and the effects of the types of heating (warm air heating, radiative heating and unheated room) and many factors (e.g. out-door air temperature, thermal conductances of the exterior walls, etc.) on the exact mean radiative heat transfer coefficient are illustrated. Moreover, a rectangular room model composed of 6 walls is used as the model to be approached to the actual ones. As the results of many numerical calculations for the model, the statistical characteristics of the value of the exact mean radiative heat transfer coefficients are clarified. The results of this paper are summarized as follows: 1) For the warm air heating, the conventionally used value of the mean radiative heat transfer coefficient is too high. Therefore, calculation using this value overestimates the heat loss. 2) For radiative heating or unheated room without ventilation, the conventionally used value can estimate a reasonable heat loss for the practical purposes unless the emmisivities of the interior surfaces are regulated. 3) For radiative heating and unheated room with ventilation, calculation using the mean radiative heat transfer coefficient can not be recommended.

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Radiators emit heat by radiation and free convection but these are extremely different from each other in the heat transfer mechanism. The present investigation is concerned with the calculation method for radiative heat output of radiators using the enclosure analysis. The analysis is extended to include the enclosures which contain both specularly and diffusely reflecting surfaces. By taking proper account of the reflectivity and the configuration factor between a real and image surfaces, it is possible to obtain a mathematical expression for the incident heat flux of the real surface and can be readily used in the enclosure analysis. Finally examples for simple model are illustrated to compare with the enclosures consisting all diffusely reflecting surface and one or two specularly and other diffusely reflecting surfaces. For the radiative heat output of radiators, little differences are recognized in these results in which the ratio of specularly reflecting surface area is relatively smaller than the total surface area.

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Solar refrigeration and heating facilities using 1330m^2 of CPC concentrators was applied to Chita Citizen's Hospital established in March 1984. The system composition is almost the same as that reported in Part 3. The present paper intends to show how the acutual operating results have been after one and a half years of operation and how precisely the theoretical calculation agrees with the actual. Results were evaluated with collector efficiency, COP of refrigeration, COP of the system, system efficiency and percentage of solar dependence. Modified collector efficiency was introduced to raise the accuracy taking the thermal capacity and time delay into account. Results for representative days in summer, winter and intermediate season were shown in detail and compared with the calculated results of the system simulation introduced in Part 3, which showed satisfactory greement. Statistical analyses of yearly results were visualized with histogram and scattergraph, showing reasonable values for each variable and index of performance compared with the theoretical development in Part 1〜Part 3. It was disclosed that the carefully designed CPC-combined solar refrigerating and heating plant could be operated efficiently, safely and stably with the aid of optimal controls, due to the high temperature difference to be utilized and the exclusion of boiling as well as freezing by applying sillicon oil as the heat media in the collector circuit.

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Two-dimensional, laminar air flow in a clean tunnel is analyzed numerically by the ψ-ω method. The purpose of this report is to propose the numerical techniques to analyze the air flow in a clean tunnel under the various flow conditions. The configuration and locations of the worktable in the tunnel are varied systematically. In addition, the manner of exhausting the air such as the position of the exhaust opening is also varied. In agreement with the visualization pictures obtained by the model experiments, the validity of the computational method proposed in this paper is qualitatively verified.

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Inclined buoyant jets performance from the room-air-distribution viewpoint can be defined by the path, together with centerline velocity and temperature-difference. This paper presents nomograms valid for computing these values. The theoretical basis for the present work lies in the model, applied by Koestel for horizontal buoyant jets, which includes following assumptions. A velocity and temperature difference profiles are presented by a normal probability curve. The expansion rates for the velocity and temperature profiles are constant, and the ratio of the expansion rates of the velocity and temperature profiles is constant.

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The existence of transient phenomena in the nucleate boiling is one of the important problems for the utilization of nucleate boiling heat transfer, because the transient points (i.e. incipient boiling point and burn out point) spread through a wide region aimlessly. In order to investigate the transient phenomena from the statistical viewpoint experimentally, an automatic experimental system for saturated pool boiling on an electrically heated wire has been developed. This system is based on a distributed multi-processer system. A master mode computer administers repetition of the experiments, obtains and calculates the data of temperature and the heat flux of the test wire. A slave mode computer controls electric current to the test wire at various operating conditions. By this system, the experiments can be repeated with high reproducibility. A number of boiling curves and the distributions of the transient points can be obtained. In this paper, the detail presentation of this experimental system is informed. The errors in the obtained data and the reproducibility of repetition in current control system are discussed. To check this system, the boiling experiment in low heat flux region has been repeated 500 runs in the case of Pt-wire immersed in n-Pentane, and those results are also enclosed.

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As a part of studies to establish a numerical prediction method of thermal environments, this paper presents a numerical calculation on the steady state distributions of surface temperature and thermal comfort index caused by radiation interaction in a heated room with floor panel heating or forced convective heating. Results of the calculation of the room air temperature, surface temperature, vector radiant temperature, mean radiant temperature, Predicted Mean Vote and heat balance illustrate well the characteristics of radiation interaction with the heating systems. This calculation procedure can be combined with the calculation of air convection as shown previously by one of the authors for the two-dimensional case.

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The thermal characteristics of a rectangular thermal storage tank was investigated experimentally by measuring the transient response of liquid temperature, for the case in which hot water was discharged through a rectangular duct into the upper part of the tank filled with cold water. Experimental parameters varied included the width of duct, the horizontal length of tank, the hot-cold water temperature difference and the flow rate of liquid. From the experimental results, the semi-empirical equation suitable for predicting the thermal storage efficiency in the arbitrary region of the tank, ηV', was finally deduced as the function of the Archimedes number based on inflow conditions, Ar_0, the Peclet number of liquid, Pe, and two dimensionless geometric parameters, φ_1 and φ_2. It was realized for the case (d_e/b)^2Ar_0<44, the occurrence of shortcut flow brought about a rapid decrease in the thermal storage efficiency.

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