Flow visualization experiments were conducted to observe the flow characteristics at orifice downstream, related to pipe wall thinning phenomena in power plant piping systems, especially for flow accelerated corrosion (FAC). Effect of orifice contraction ratio on reattachment points of flow separation was investigated. Reattachment length from the orifice was able to be expressed universally by using non-dimensional length divided by orifice height. With this method of evaluation, flow separation region would be within 3 times of diameter (3.0D), at the utmost, even with largest Reynolds number condition in actual plant piping. Since FAC susceptible area is assumed to be in the separation region, from previous studies, 3.0D) would be conservative enough, for pipe wall inspection region at orifice downstream, which is the regulated value in the current pipe wall thinning management standard for domestic nuclear power plants.

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In order to detect small local wall thinnings, it is strongly expected to excite guided waves with higher frequency. In this report, the analysis of wave propagation in a plate with thickness of 10mm is performed with the finite element method and is verified with a plate specimen with the same thickness, which shows that it is possible to excite guided waves to propagate in such a plate at the frequency of 2MHz when a shear oblique transducer with refraction angle of 45 degrees is used. The detection of artificial defects introduced in the plate specimen is performed by guided waves with frequency of 2MHz. The SN ratio of the reflected echo from these defects at the frequency of 2MHz is larger at least 5.6dB than that at the frequency of 0.3MHz reported previously, which results in detecting small defects easily that is difficult for guided waves with frequency of 0.3MHz.

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We developed the device to detect thinning of pipe thorough heat insulation in Power Plant, etc, even while the plant is under operation. It is necessary to test many parts of many pipes for pipe wall thinning management, but it is difficult within a limited time of the routine test. This device consists of detector and radiation source, which can detect the pipe (less than 500mm in external diameter, less than 50mm in thickness) with 1.6%-reproducibility (in a few-minutes measurement), based on the attenuation rate. Operation is easy and effective without removing the heat insulation. We will expand this thinning detection system, and contribute the safety of the Plant.

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The inspection machine for boiler tubes of thermal power generation facilities was developed for the both purposes of evaluating soundness more precisely, and of reducing maintenance expense. To begin with, the examination machine that could measure wall thickness and outer diameter of boiler tubes in succession was produced experimentally. Next, thickness measurement of the upper section of economizer panel of Tomatou-Atsuma No. 1 Boiler was performed. As a result, it was confirmed that the machine could inspect soundness of boiler tubes with enough precision in practical use.

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The structures of Sodium-cooled Fast Reactors (SFRs) are designed to mitigate thermal stress by thin-walled piping, to accommodate thermal expansion by long piping with elbows and to make sure of seismic insulation by piping support system. Therefore, it is important to measure the stress on the cooling system piping, and the displacement and vibration on the related components in order to assure the structural integrity. In the experimental fast reactor Joyo, displacement and vibration measurements of the primary cooling system have been carried out using Fiber Bragg Grating (FBG) sensors to evaluate the durability and measurement accuracy of FBG sensors in a high gamma-ray environment. The data were successfully obtained with no significant signal loss up to an accumulated gamma-ray dose of approximately 7×10^4 Gy corresponding to 180 EFPDs (effective full power days) operation. The measured results indicate that the FBG sensor is applicable for monitoring the displacement and vibration aspects of SFR's cooling system integrity in a high gamma-ray environment.

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This paper reports solutions for high tension bolt fasteners by optimized design for compact hydraulic nut characterized by ultra-high pressure, special metal seals and split locking ring that offer versatile opportunity for critical duty equipment users with easy and reliable maintenance.

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CRIEPI has developed a high accurate, low cost, efficient flaw depth sizing technique in ultrasonic nondestructive inspection, which is easy to use in comparison to standard techniques such as crack tip diffraction and TOFD techniques. This technique is called the short path of diffraction (SPOD) technique. This paper deals with applicability to front surface flaws. SPOD is possible to apply to depth sizing of front surface flaws.

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Visualization experiment and numerical simulation using a finite element method are carried out in order to understand the ultrasonic wave propagation behavior in Inconel weld zone of dissimilar metal weld (DMW). In numerical simulation, DMW is modeled as the acoustic anisotropy considering crystal orientation in welds. Numerical simulation is compared with visualization result and the validity of DMW modeling is confirmed. It found that the propagation path of shear wave changes so that it may travel in the growth direction of columnar grain, but DMW has small effect on longitudinal wave propagation. In general, longitudinal wave was used in the inspection of DMW. From results of ultrasonic inspection using phased array probe, it found that only small echoes from slit in welds without echo from boundary of welds are observed by longitudinal wave but clear echoes from slit are observed by shear mode, especially in inspection of a butter zone from the butter zone side. These echoes by shear mode appear at deeper position than longitudinal one.

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In Japanese Nuclear Power plants, many IGSCC had been detected in re-circulation line made of Stainless Steel. Therefore these piping welds have to inspect in short intervals. In addition the Japanese maintenance code had been published. The needs of crack depth sizing with high reliability is getting greater in Japan. IHI developed phased array technique for efficient crack detection, and the IGSCC depth sizing. The developed technique use the 2D phased array probe with wedge, and this probe can be applied for crack detection and crack depth sizing.

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All of gas turbine (GT) blades that come to the end of those lives are replaced with new ones in the scheduled inspection period. The blade is so expensive that the expansion of its life is considered as one of important subject to reduce the maintenance cost. In this study, three-dimensional thermal stress analysis and thermal fatigue damage estimation was performed for a 1300C-class GT blade under assumed operating conditions. As a result in the three-dimensional thermal stress analysis, it was revealed that the outer surface of the blade was under bi-axial compressive stress condition in start and steady state operation. Then consequently in the damage estimation, it was clarified that the middle of suction side of the blade was the most severe in terms of thermal fatigue damage and the reduction of combustion gas temperature had the effect of the reduction of damage.

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Small punch creep (SPC) tests were conducted in vacuum to evaluate creep property of Ni-base superalloys, Inconel738LC, Alloy706 and Alloy718. Test results were correlated with uniaxial creep tests in terms of the conversion of applied load to stress. Rupture lives of uniaxial and SPC tests were arranged against the applied stress and load using Larson-Miller parameter respectively. Then, the ratio of load (F,N) to stress (σ, MPa) was calculated so that both curves were overlapped each other. As a result, the correlation was estimated to be F=1.7σ (IN738LC), F=1.1σ (Alloy706), F=1.2σ (Alloy718). Fracture morphologies were intergranular fracture (Alloy706, Alloy718), intergranular+transgranular fracture (Inconel 738LC). The ratio of F to σ became smaller as the fracture morphology changed to brittle.

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In order to develop a prediction method of Aluminum content in bond coat (BC) of thermal barrier coating (TBC), specimens are exposed to high-temperature atmosphere. The microstructural change of BC is observed and the Al-content is measured by means of an electron probe microanalyzer (EPMA). The Al-decreased layer (ADL) grows at the vicinity of BC surface after the test since Al diffuses to the surface due to the oxidation. The Al-content in BC decreases in proportion to the ADL thickness. On the basis of the relation, the time to reach an arbitrary Al-content can be predicted.

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A numerical model of electret power generator has been developed. Computational results with the present model are in good agreement with our previous experimental data. It is also found that in-plane electrostatic force is almost constant and 0.1-0.2N irrespective to the oscillation direction. Parylene seismic structures with embedded electrode have also been macrofabricated. It is demonstrated that large-amplitude oscillation at low-resonant frequency can be achieved with almost constant electrical conductivity.

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We fabricated micro-generator based on thermoelectric materials and measured its performance. The Bi_2Te_3- Sb_2Te_3 is used as a p-type material, and the Bi_2Te_3- Bi_2Se_3 is used as an n-type material. We fabricated shadow masks of Si with Si_3N_4 by using standard micro-fabrication processes for patterning the device. Thin films of both p-type and n-type Bi_2Te_3 are deposited by a flash evaporation method through the shadow masks. The maximum output voltage of the micro-generator is 6.7mV at 2.5K temperature difference.

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It is requested to develop a small and highly efficient heat exchanger for small size energy equipment such as fuel cells and CO_2 heat pumps. In the present study, the high pressure resistant micro-channel stacked heat exchanger had been developed. The heat transfer area for each volume of this device is quite large. Since the distance between the micro-channels in the device is small, the thermal resistance is small. This device can bear for very high pressure condition since the device is main factored by the diffused bond method Due to the very high pressure resistance, this device can be used for high flow rate condition with boiling and condensation. As the results, it is clarified that above features make the device to achieve very high performance more than hundred times larger heat transfer rate than the existing heat exchanger.

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Heat transfer and flow behavior in the mini tube bank was examined. The tube bank was composed of 1mm diameter wires and a 30W×15H mm flow channel. The wires were arranged 5×5 or 1×5 in an inline lattice. Water was used as the test fluid. A flow rate was varied in a range of the Reynolds number Re=uD/v of 1〜400, where u was the approaching velocity. In usual size tube banks, a heat transfer coefficient increases as the tube row goes downwards. The increase saturates around 10th row. Contrary to it, the heat transfer coefficient decreased as the flow proceeded downwards. A flow state was visually observed by mixing a fluorescent dye and illuminating fluorescent dye particles by a YAG laser beam sheet. The flow state was recorded with a high speed video camera. The visualization revealed that the down stream wire was surrounded by the wake of the upstream wire, which made the flow state around the stagnant point region of the down stream wire less turbulent. The heat transfer deterioration with flow going downstream was observed until the Reynolds number 120〜150. Around Re=150, the jumping up of the heat transfer coefficient in the rear bank occurred. Flow and heat transfer analyses were performed with a STAR-CD code. The same trend was confirmed in the analyses.

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Combustion characteristics of propane flame with high space heating rate in an annular-type combustor for a several hundreds W-class micro gas turbine were investigated. The flame shape, flame stability limit, flame length and temperature distribution in the combustor were measured varying the orifice ratios, which were 0, 0.19 and 0.36, as the experimental parameter. It was considered that the flame shape was influenced by the combustor axial velocity at the orifice, orifice ratio and fuel/air concentration in the orifice upward region. In the case of orifice ratio of 0.19, a circular propane flame with short flame length was observed in the orifice upward region. Temperature distribution in the combustor showed that this flame could have high space heating rate.

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A micro catalytic combustor using high-precision ceramic tape-casting technology for micro thermophotovoltaic system has been developed. Pd/Nano-porous alumina is employed for the catalyst layer in order to achieve high temperature operation. Catalyst arrangement that gives much smaller temperature gradient has been proposed based on a series of CFD analysis. Preliminary experiments with a combustor prototype show that high heat generation density can be achieved even with partial distribution of the Pd catalyst. The combustor can achieve sustainable operation up to 660℃.

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Numerical computations of compressible low-Reynolds-number (Re) flows in a small radial turbine with rotor diameter of 46mm are performed based on the Reynolds-averaged Navier-Stokes (RANS) simulation with a low-Re turbulence model. In the computations, the conditions of pressure ratio of 1.5 and isentropic velocity ratio of 0.6 are assumed, and the tip clearance of 2.5% of the blade height is taken into account. The results are compared with those by Large-Eddy Simulation (LES) and RANS simulation based on the Baldwin-Lomax turbulence model.

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The loss generation factor of two-dimensional radial compressors is investigated by CFD analysis. The main loss factor is the separated flow and main flow interaction,and wall friction in the impeller. According to these results, we modified the impeller blade design by changing the blade inlet and outlet angles. As a result, the adiabatic efficiency was improved by about 10% compared to the old design. We also investigated the tip clearance effects by CFD analysis. It showed that the leakage flow and main flow interaction is one of the main loss factor. When the tip clearance is 7% of the blade height, the adiabatic efficiency and the maximum pressure ratio deteriorated by about 10% and 0.12 points respectively compared to the no do clearance.

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A new method for cooling the micro gas turbine rotor was proposed. Using a hollow shaft, cooling air is actively induced into the rotor. To access the effect, CFD calculations were conducted. The rotor temperature of a micro gas turbine would be unacceptably high, because the compressor is placed nearer to the turbine by making the scale small. The heat flux from the turbine has great influence on deteriorating the compressor efficiency. As the results, some characteristic of flow fields and cooling performance were realized. This new cooling method has a great potential as a heat shield in a micro gas turbine.

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We made a prototype Joule-Thomson micro-cooler that was fabricated on Si wafer by photofabrication. The micro-cooler in the present study uses ethylene as a refrigerant. Inlet and outlet gas pressures are set to 2.5MPa and 0.1MPa, respectively. There are slits on counter-flow heat exchanger to prevent heat flow to the cold region along Si wafer. Evaporator temperature reached 270K with pressure of 2.5MPa and mass flow of 9.98mg/s, and we confirmed the operation of micro-cooler. We also performed numerical analysis of heat exchanger. It was found that the mass flow rate of the present experiment is too large. The temperature effectiveness can be improved by decreasing mass flow rate and also by decreasing thermal conductivity of solid material.

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The development of a novel gas micropump suitable for integration with micro chemical chips is reported. A pumping principle was adopted that utilizes the volume change caused by heating and cooling air in the pump chamber, and the flow rectification effect based on fluidic diodes, in order to realize a small size without moving parts. For heating the air, a micro heater capable of rapid switching between high temperature (〜1000℃) and room temperature is required. In this work, a prototype device with a self-standing highly-doped silicon thin film heater was fabricated and characterized.

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An experimental study was conducted to investigate the flow-induced vibration characteristics of socket-supported (flexible) tube bundles in cross flow. In order to simulate the partial support of clearance holes of baffles in shell-and-tube heat exchangers, in-line and staggered bundles comprising glass rods mounted flexibly inside circular supporting socket in the channel wall were constructed. The two test sections were made transparent to facilitate flow visualization and whole-field measurement by PIV. The results obtained in this study confirmed that the vibration characteristics of tube bundle are closely related to the velocity fluctuation of the surrounding flow field.

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The photo resist stripping process in photo lithography plays an important role in manufacturing large-scale integration. In the present study, experimental information is obtained to establish highly concentrated ultra pure ozonized water technology for stripping the photo resist, in stead of sulfuric acid, hydrochloric acid etc. In the experiment, rotating flows of the ozonized water on the photo resist on silicon wafer is established with the irradiation by excimer light. Ozonized water on the rotating wafer forms Radial Liquid-film flow. After the process, the thickness of unremoved photo resist on the wafer is measured by ellipsometer. And wettability on the photo resist is also measured. As the result, it is clarified that the irradiation of excimer light and the rotating rate of silicon wafer contribute high efficiency of photo resist removal rate compared to merely ozonized water.

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Recently, as a useful noninvasive measurement, computed tomography is extensively applied to real industry to measure and visualize particle behavior in a cross-section of a pipeline. In this research, particle concentration distribution images of dense two-phase solid/liquid flow are obtained in a horizontal mini channel using impedance-computed tomography. Two-phase solid/liquid flow mixed by pure water and nano magnetic particles is imported to a mini channel with 8 electrodes by a micro pump. The impedance between each electrode pair is measured for different magnetic particle consistency. Then the particle concentration distribution images are reconstructed based on the measured impedance values

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A resistance CT for solid liquid two phase flow has been developed. The experiment was conducted with various sizes and places of the acrylic stick in order to check the CT performance. As a result, the CT sensor with the large electrode and a lot of numbers electrodes visualize the stick position clearly. And the recognition of the position is possible. The impedance is measured with various frequencies to adjust the resistance component to nearly 0. And 3000kHz frequency is used for the visualization in the pipe under the condition that an acrylic stick was put in an acrylic chamber.

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The electro-void fraction meter (Capacitance Type meter) is practical for high void fraction measurement. It can be used with various shapes of flow conduits such as round, rectangular and rod-bundle geometries. The principle of the meter is that the electrical capacitance of a gas-liquid two-phase flow changes with respect to the void fraction. High-frequency power supply enables to measure the void fraction of the pure water. It was confirmed by an air-water two-phase flow experiment that void fraction can be obtained in real time by measuring the capacitance of the two-phase flow. Void fraction ranging from 0% to more than 90% in a 37-rod bundle was successfully measured under 7MPa pressure conditions.

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The aim of this study is to reveal the basic flow characteristics of the free surface vortex.. For investigation on the working fluid effect, temperature of the fluid was varied. Flow configuration was altered by changing the water level.. We found out that all these parameters have considerable influences on the behavior of the free surface vortex. The flow field was measured by using PIV. The measurement results show a forced circulation region near the circulation center of the vortex, followed by a free circulation region surrounding the forced circulation region in the vortex structure. On the other hand, the flow field measured at the vertical cross section of the vortex revealed an uprising flow region over the exit drain hole.

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Supersonic steam injector is the one of the most possible technologies for next generation nuclear reactor systems. The supersonic steam injector has dual functions of a passive jet pump without rotating machine and a compact and high efficiency heat exchanger, because it is operated by the direct contact condensation between supersonic steam and subcooled water jet. In order to apply the steam injector to actual reactor systems, it is necessary to clarify the flow behavior and heat transfer in the supersonic steam injector which are governed by the complicated turbulent flow with a great shear stress of supersonic steam. However, in previous study, there is little study about the turbulent heat transfer and flow behavior under such a great shear stress at the gas-liquid interface. In the present study, radial velocity distributions and radial temperature distributions are measured experimentally. Turbulent flow behavior including the effect of the interface between water jet and supersonic steam is developed based on the eddy viscosity model. Radial velocity distributions and the turbulent heat transfer are calculated with the model. The calculation results are compared with the experimental results done with the transparent steam injector.

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As a candidate for next generation reactor, the innovative Flexible-fuel-cycle Water Reactor (FLWR) adopts a remarkably tight triangular lattice arrangement with about 1mm gap spacing between adjacent fuel rods. In relation to its design, this study presents a statistical evaluation of numerical simulation results of a detailed two-phase flow simulation code (named TPFIT). In order to make clear mechanisms of cross flow in such tight lattice rod bundles, the TPFIT is used to simulate cross flow between two modeled subchannels. Attention was focused on instantaneous fluctuation characteristics of differential pressure between two subchannels and gas/liquid mixing coefficients. With the calculation of correlation coefficients between the differential pressure and gas/liquid mixing coefficients, the time scales of cross flow, e.g. lag times were evaluated, and the effects of mixing section length, flow pattern and gap spacing on correlation coefficients were extensively investigated. The difference in mechanism between gas and liquid cross flows was pointed out.

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Thermal-hydraulic design of the current BWR is performed by correlations with empirical results of actual-size tests. Then, when the reactor of new design is developed, an actual size test is required to confirm or modify the correlations. Development of a method that enables the thermal-hydraulic design of nuclear rectors without these actual size tests is desired, because these tests take a long time and entail great cost. For this reason we developed an advanced thermal-hydraulic design method for BWRs using innovative two-phase flow simulation technology. In this study, detailed two-phase flow simulation code using advanced interface tracking method: TPFIT is developed. In this paper, the TPFIT code was applied to simulation of two-phase flow in modeled 2 subchannels of BWRs rod bundle, and the existing two-phase flow correlation for fluid mixing is evaluated using detailed numerical simulation data.

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In the JAEA, in order to investigate influence of the fuel rod bowing upon the critical power of the fuel assembly in the Innovative Water Reactor for Flexible Fuel Cycle (FLWR), the large scale thermal hydraulic experiment which simulates the fuel rod bowing was performed, and the fuel rod position in the test section was measured using the X-ray CT equipment. In this study, in order to investigate influence of the displacement of the fuel rod from the design-based rod position upon the critical power of the test section, the experimental analysis using the subchannel analysis code NASCA was performed based on the fuel rod position measured by the X-ray CT.

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In a plug transportation that is one of gas-solid two-phase flow, the predicted equations on particle velocity within a plug and pressure drop in a horizontal pipe have been formulated. The agreement between values calculated by these equations and experiments that changed solid-air mass flow rate, pipe diameter, kinds of particle was obtained. The error between them is almost within 10%. In order to confirm the validity of supposition to derive these equations, particle velocity distribution within a plug in the directions of flow and radius, and particle velocity transformation from a stationary bed to a plug have been analyzed by high speed camera and PIV. As a result, there is no particle velocity distribution in a plug, and particles are accerated uniformly in extra part of a plug. Particles in a plug are fixed relative to each other and so they all move with the same velocity.

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Onset of nucleate boiling -ONB- and critical heat flux -CHF- on subcooled flow boiling under oscillatory flow and vibration conditions, focusing on liquid velocity, amplitude and frequency of oscillations were investigated experimentally. Experiments were conducted using a copper thin-film and subcooled water in a range of the liquid velocity from 0.27 to 4.07m/s at 0.10MPa. The liquid subcooling was 20K. Frequency of oscillatory flow was 2, 4 and 6Hz, respectively; amplitude of oscillatory flow was 25 and 50% in a ratio of main flow rate, respectively. For the vibration condition, acceleration of vibrator was 1.3 and 4.2m/s2, respectively. Temperature at ONB and critical heat flux for oscillatory flow were lower than those for steady flow. The decreasing of liquid velocity by oscillatory caused the ONB and the CHF to decrease. Critical heat flux for the vibration condition was higher than that for steady flow. The effect of liquid oscillatory flow and vibration of heater on CHF examined through the liquid velocity profiles under oscillatory flow and vibration conditions.

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Critical Heat Flux (CHF) in a non-uniformly heated tube is a very important factor in designing boiling two-phase flow system. In this series of studies, the re-distribution of liquid film was considered as the significant influence factor of the CHF in a vertical upward non uniformly heated tube. In present study, by using the inclined heating channel, the magnitude of the re-distribution was varied. The experimental results under inclined channel expressed the quite different results with that of the vertical tubes, but these characteristics have been well explained by considering the mechanism of the re-distribution of the liquid film.

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原子力機構が開発した稠密バンドル用限界出力相関式、およびMartinelli-Nelson二相増倍係数をTRAC-BF1に集約し、コード改良を行い、低減速軽水炉用熱設計コードが開発された。本研究は、開発したコードを用いて、900体の燃料集合体から構成される1356MWe増殖型低減速軽水炉の実機炉心の熱工学的成立性を評価した。評価に当たって、通常運転時及び運転時異常な過渡変化において、沸騰遷移を許容しないという従来BWR熱設計方針を用いました。評価手順は、まず運転時異常な過渡変化におけるMCPRの変化量ΔMCPRを評価し、これを基ついて通常運転時必要なMCPR及び冷却材流量を算出した。その結果、強制循環型低減速軽水炉の熱工学成立条件は、運転制限MCPRが1.32(炉心平均質量速度が640kg/m^2s)以上にすることである。また、自然循環型の熱工学成立条件は、運転制限MCPRが1.19(炉心平均質量速度が560kg/m^2s)以上にすることである。

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Characteristics of subcooled boiling are nonequilibrium and be caused by a nucleation boiling at the same time as a bubble condensation. It is difficult that a composite equation, which is applied for a two fluid model and three a fluid model for a phenomenon analysis, is established only fluid dynamics. Therefore, the composite equation is necessary that it is installed the liquid-vapor interaction equation. The establishment of the interaction equation is necessary several parameters. The several parameters are bubble diameter, bubble shape, interfacial density and interfacial share stress. It was known that the behavior of the bubble determines a void fraction, but it is not clear the relation. In this study is intended to consider that the bubble behavior, which was analyzed by high speed camera, has an effect on flow and void fraction. As the result, the diameter and a condensation velocity of the bubbler, which departs from heater, affect the flow and the void fraction.

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A new measurement technique referred to as multi-wave ultrasonic method was applied to measuring slug flow. The technique was developed for measuring two-phase flow using two different ultrasonic frequencies. The technique employs a multi-wave ultrasonic transducer (TDX) which includes two different ultrasonic elements. With emitting two kinds of ultrasonic at the same time, two kinds of ultrasonic echo signals can be obtained. The echo intensity reflected from liquid-gas interface is higher than that from micro particles seeded in water. Comparing with the each signal, echo signals from liquid-gas interface and micro-particles can be divided. Applying an ultrasonic time-domain cross-correlation method for the signals, velocity distributions of the both phases can be obtained at the same time and the position. Comparing the velocity data with the obtained images by using high-speed camera, it was confirmed that the multi-wave method can measure the both liquid and gas velocity distributions at the slug flow.

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Power signals from an instability transient event in a nuclear power plant are analyzed by the wavelet technique. Besides determining the dominant oscillation frequency of the event, other frequencies were also found in the power signals and were analyzed for their importance to the event. The instability event will be described and results from traditional Fourier and wavelet analysis will be presented and discussed. The wavelet technique is shown to be a powerful additional tool to the traditional Fourier analysis in the signal analysis from transient events in nuclear power reactors.

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In order for economically viable distributed generation systems for local community to spread, it is essential to develop an efficient and low-cost heat supply system. We have proposed a new heat supply system presented at ICOPE-03 Kobe and ICOPE-05 Chicago. The key technology for the system is to connect compact heat supply units installed in all the households of the local community, such as a condominium, by a single loop of hot water piping. Phase change material such as paraffin was used for a heat supply unit as heat storage material. However we have developed a new heat supply unit made of plastic water tank for ease to use and a serious cost reduction. Hot water for space heating is used as heat storage material. Some experiments for a heat supply unit and dynamic simulations for heat demand have been conducted, such as heat storage and supply of the heat supply unit, and COP evaluation of a new CO_2 heat pump system using low- temperature exhaust gas. In this paper, experimental results on the performance of the new heat supply system installed to 7 households in condominium, and evaluation of dynamic simulation for 50 households using 1B hot water piping are presented.

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