Usually solar panels are coated with anti-reflection films on their surface. The films aim to reduce and control the reflection from the surface of the panels. If multilayer thin films coating on the solar panel has the function of spectral control considering spectral-response characteristics of the absorbing layer of solar cell in addition to the anti-reflective function, optical and electrical losses will be reduced and the conversion efficiency will be improved. Several design results of multilayer thin films for CIGS solar cell by using the optimum design program for optical thin films developed in our laboratory are reported in this paper.

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A non-sun tracking concentrating solar module composed of solar panels and reflectors was proposed in order to improve the generating performance and its characteristics was evaluated. In this solar module, direct sunlight as well as reflected sun-light was irradiated to the solar panel, as the module is equipped with reflector in front of the solar panels. Outside test data showed this module generates output power 1.5 times larger than that of the conventional ordinary solar modules. These experimental data mean the reduction of number of solar panels by approximately 40% in the photovoltaic systems.

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Desiccant air-conditioning system is an energy saving system, because it can use waste heat and solar energy to regenerate desiccant rotor. In this study, regeneration of desiccant rotor with direct heating by concentrated solar energy was examined. Experiment of regeneration by heater confirmed basic performance of the desiccant rotor. In the experiment of regeneration by concentrated solar energy using a Fresnel lens, relationship between the irradiance and the performance of dehumidification was clarified. Comparison of regeneration performance between them indicates that direct solar irradiance of 800W/m^2 results in the similar regeneration capability to that of conventional heating.

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The Aerodynamic performance characteristics of a horizontal axis wind turbine (HAWT) using by NACA44xx aerofoil series as known the detail date of C_L C_D were investigated theoretically by an analysis involving a combination of momentum, energy, and blade element theory by means of the strip element method. In this study, two approaches involving combination analysis are made use of, namely, the thrust-torque and thrust-energy methods. Although both approaches yield identical results, the latter is superior for evaluating the relationship of the kinetic energy of the flows on blades. The theoretical characteristics of the HAWT using the different types of the blades such as, blade dia., coard length, twist pitch angle, are discussed by reference to the power torque and thrust coefficient, C_p, C_q, C_T, C_<th>, and the tip speed ratio λ from the point of view of the optimum design and controlling.

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Vertical axial cross flow type of wind turbines are considered to have superior characters in comparison with the conventional propeller type of HAWT, i.e., operating as strong torque at starting and all direction of the wind without the yaw drive system which lead to the simple structure and low cost while the performance is inferior to that in power. In this paper, aerodynamic performance characteristics of the cross flow type of wind turbine were studied experimentally by using sub-scale model, especially considering the effect of guide vanes and its arrangement. Subsequently, two upper and lower front guide vanes were cleared to be effective in performance. The aerodynamics characteristics of the turbine with the conventional / two guide vanes for 16 and 30 rotors condition were discussed to specify the performance, correlated by tip speed ratio with the power and the torque coefficients.

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In recent years, there are activities of making fish farms in offshore area because of the generation of the red tide and the deterioration of the surrounding environment by overcrowded cultivation in coast area. However, following problems occur if fish farms were made in offshore area. First, it is difficult to use gravity type breakwater to make calmness water area for large depth. Second, energy supply is not easy because there is far away from the land. To resolve these problems, we install floating breakwater instead of a gravity type breakwater and get energy to be necessary in fish farms from the motion of the floating breakwater at the same time to reduce the wave. Then we set the pendulum on the floating breakwater model with reverse-trapezoid section and experimented to get energy from the swing of the pendulum by the movement of the wave. In this paper, we present the result of the experiments and describe basic characteristics of this model.

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Adhesion problem of marine organisms often becomes a problem, in the case of ship, marine floating construction and sluice gate of power plant. These make fluid resistance of a hull increase, cause a buoyancy fall, or cause reducing coolant etc. Although these are chiefly removed by manual operation now, immense expense and immense labors, such as personnel expenses and time and effort, are needed. We tried application of an underwater shock wave, in order to solve these problems. Interference of a shock wave and the mechanism of marine organisms exfoliation were explored using the explosive and PMMA plate, which imitated a marine organisms adhesion. The process of exfoliation of organisms from PMMA plate was observed by using of the high-speed camera.

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This paper deals with the performance test for a prototype model of resonance-tube-type cooling device. In the experiment, it is examined that effects of the stack shape, stack length, stack position, operating frequency and operating sound levels on the cooling capability. Results of the experiment show that the temperature change of stack suddenly happened just after the output from sound source and it becomes fixed afterward. In addition, there is the most suitable stack position by a difference of the stack shape, stack length.

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We have examined one office model in which radiation panels were used for a cooling system by a CFD code SCIENCE. Three cases of radiation panels arrangement were examined. One case was only using a ceiling radiation panel and the other two cases were not only using the ceiling radiation panel but also using the radiation panels of tables and partitions in task areas. In examinations we kept the average PMV(Predicted Mean Vote) of task areas 0.5 and control the temperature of some panels. Results proved that using the radiation panels of tables and partitions in task areas could decrease the cooling load comparing with using the ceiling radiation panel only.

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A multi-cone diffuser is difficult to treat in CFD analysis of the airflow in rooms, because its complicated shape tends to make complicated flow near the diffuser and needs many meshes. Authors have proposed a kind of BOX method that uses the measured velocities and turbulent parameters as the boundary conditions around the diffuser. This paper investigates the influence of the limitation of space and the non-isothermal supply airflow. CFD simulations using unstructured meshes were conducted and these influences were checked. The area where the BOX method can be applied was proposed and CFD analysis using structured meshes by BOX method was conducted as well.

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Direct humidification using compressed air atomizer is one of the conventional methods at printing factory. Atomized water removes heat from air when it evaporates so it contributes to both heating and cooling cost. We have improved the control system that can keep the humidity constant using dual control valves. When the humidification system is being applied to existing factory, the examination of setting-up interval of atomizers is needed to uniformity the humidity in clean room. In this study, we tried to estimate the distribution of humidity using simulation of CFD.

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It is most important to exactly determine view factors in heat transfer problems. Although Monte Carlo method is often used to determine view factors with complicated forms, it requires much computational time. Pyramid Projection Method that we propose can determine view factors at high accuracy and in reasonable computational time. This method was applied to the heat radiation problem of a room with a stove of 800℃ and with two windows of 0℃. It was shown that the computational time of this method along with hardware accelerator became a few hundreds times faster than the usual method.

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In this research an inverter air-conditioner model, which takes into account control logic, refrigerant cycle and heat exchange process was used. By coup ling this model with the CFD model simulation of air-conditioner operation was carried out under varying condition of insulation, air supply direction, location of control sensor with this simulation. The simulated indoor environment and operational condition of air-conditioner is presented in this paper.

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The rise in suction temperature of outdoor units of air conditioners is caused by installing many outdoor units on the roof of buildings. This problem is due to short-circuit air flow of the exhaust air of outdoor units. Our aims are to investigate various factor of short-circuit air flow and improve this problem. In this paper, by using original CFD (Computational Fluid Dynamics) code 'SCIENCE' have been developed by us, the influence of the wall on the roof of the building upon suction temperature of outdoor units was investigated. As a result, the phenomenon that the units in the lower stream suck exhaust air of the units in the upper stream due to negative pressure arisen by separation of main flow from the wall, and the rise in suction temperature of units were confirmed.

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This paper describes about observational studies for thermal environment arround the air cooled outdoor units installed on the roof of a building, especially as far as the air cooled electric heat pump concerned, the impact of the Short-Circuit (SC) phenomenon on the energy consumption for air conditioning was quantitatively evaluated. The realities of the SC phenomenon were understood from the observational result, and it was clarified that SC phenomenon is affected by the layout of the outdoor units and the wind condition in the surrounding. Moreover, it was about 3% that amount of energy consumption for air-conditioning increased by the SC phenomenon.

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The water spraying device set up in air-conditioning outdoor machine decreases the condensing pressure of the compressor by the effect of the evaporation cooling of the water. As a result, it induces some effects--the high-pressure cutting prevention, the improvement in efficiency, and the energy conservation at the time of the maximum air conditioning load generating. In this article, by the measurement in the operating state, the effect of energy conservation of the air source heat pump chiller by water spraying is verified considering energy consumption accompanying refining of water. Moreover, the effect of changing from sensible heat to the latent heat is additionally verified.

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This research proposes operational method to improve system efficiency regarding water cooled packaged Air-conditioning (A/C). Water cooled package A/C works all year air cooling and is installed at telecommunication building and data center. As an A/C which performs annual A/C operation, the operation range of the low-temperature domain of condensation temperature was expanded, and the air cooled packaged A/C machine has so far realized technology which raises the efficiency in every year. This technology can be applied to a water-cooled package A/C, and improvement in efficiency of a refrigeration cycle can be aimed at by lowering circulating water temperature. On the other hand, the efficiency in the whole A/C system reeds to consider and estimate the power consumption of a cooling-water system. The simulation model incorporating the control technique which reduces the power of the cooling-water system by operation/stop control of a cooling tower was created, and the system efficiency through every year was computed from steady-state simulation of a system. Consequently, at the efficiency of an A/C system including a cooling-water system, lowering the minimum value of circulating water temperature did not necessarily restrict that it was good, but it became clear that there is the operation temperature range of the optimal cooling water according to the operating ratio of an A/C machine. And, it was expected by proposed control that it improved about 12% at the time of the partial load of 30% of A/C machine operating ratios

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In recent years global environmental problems become aggravated, and various energy-saving function and method have been introduced in vending machine. However, it is reported that useless energy is consumed because the amount of power consumption changes greatly by the installation environment in actual operation. Then, it aimed to achieve efficient conservation of energy by managing operation information on the vending machine, we did the monitor investigation to the vending machine in the university premises. When the conservation of energy setting matched to the use state was given, the amount of power consumption of about 12.2% was reduced to 25 vending machines in premises. As for this, the effect of 3.9t is forecast during year by the amount of the CO_2 reduction. Moreover, the environmental load of the operation phase of the vending machine was evaluated with the concept of eco-efficiency.

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Heat generation in racks loaded with servers and storage devices has become much larger over recent years. At iDCs (Internet Data Centers) the problem of high local temperatures has arisen because of the mixed installation of these latest devises with legacy systems. In particular, it is difficult to maintain an even air temperature in room with a conventional under-floor air-distribution system used at iDC. Accordingly, to control such high local temperatures, we have developed a "Task/Ambient Conditioning System for Data Centers". In this system, the rack mount, task unit, and overhead task unit are developed to cool local high temperature areas in data centers. In this report, assuming that these units are open-rack types, the effects of these units on improving the temperature environment in a server room are evaluated.

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Internet data center are helping to expand the network society throughout the world. These data center require air conditioning to operate, and raising the efficiency of their cooling systems can have significant benefits such as the prevention of equipment failure and the saving of energy as well as improved cost performance. A data center in which much heat-generating equipment has been installed produces a large amount of heat, and achieving a balance between cooling power and fan driving power holds the key to greater efficiency. This paper describes about airflow and thermal environment around server-rack at data center. We evaluated the influence, which indoor temperature and airflow gave to intake temperature of the apparatus.

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It is well-known that high strength aluminum alloy 2024 has high mechanical strength but poor corrosion resistance. The Al-Cu intermetallic compound particles exposed on aluminum alloy 2024 matrix are detrimental to corrosion. We have shown that the Al-Cu intermetallic compound particles exposed on high strength aluminum alloy 2024 are selectively removed. It is found that the intermetallic compound-free surface is preferable for the surface treatment such as Zn plating. Zinc has a function as sacrificial anode because zinc is less noble than aluminum.

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A new distillation system is proposed. The system uses decompression boiling, multi-effect, and heat pump to solve the problems of water shortage. We studied with a small-scale indoor apparatus which has only 200cm^3 inner volume of each evaporator to confirm whether it is a feasible principle. Experiments were conducted at temperatures between 15 and 20℃ as cooling water and 37 and 40℃ as the heat source, and distilled water was always obtained at every stage of multi-effect still. The results show the possibility to get the ability of the system as high as that of existing large-scale desalination plants. The present distillation system has the possibility to improve the efficiency by adding another stage of still and getting the higher COP of heat-pump.

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This paper reports the demonstration experiment of a power and refrigeration hybrid cycle which employs ammonia-water mixture (AWM) as working fluid. The hybrid cycle is the cycle which an ammonia absorption refrigerator and the AWM turbine cycle are connected by several pipelines. To demonstrate the performance enhancement of the hybrid cycle, steady state characteristics are experimentally investigated. The authors especially focused on the COP, heat source steam consumption rate and heat of rectification when the ammonia mass fraction of rectifier inlet strong solution becomes higher. As a result, the COP and heat source steam consumption rate improved about 20%.

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Generally, the heat transportation for a long distance is necessary to use the waste heat effectively. The purpose of the study is to evaluate the performance of heat energy transportation using Solution Transportation Absorption cycle: STA analytically and experimentally. The STA system is based on the principle of the absorption cycle. The absorption cycle consists of 4 heat exchangers; generator, condenser, absorber and evaporator. The STA system has generator and condenser on the heat supply side while absorber and evaporator on the heat demand side. The solution is transferred between heat supply side and demand side, which works as a medium of heat energy transportation. Since heat energy is converted into the concentration difference of the solution. This paper discussed the mathematical analysis of the STA system when it was used for the hot water provision and the comparison STA system between conventional systems. The results of the simulation of the STA system show that COP decreases when the ambient temperature decreases. And, the results of the comparison show that the STA system has smaller inside diameter of pipeline, much longer transportation distance, and better efficiency of transportation than conventional systems.

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Hydrogen absorbing alloys have been studied as a method for storage of hydrogen. The MH actuator is being developed as a method for directory obtaining a mechanical force using hydrogen pressure generated by a temperature difference applied to a Hydrogen absorbing alloy. In this study, seawater exchange system was constructed experimentally using a MH actuator. We verify the performance and characteristics in a laboratory test.

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An effective-use method of exhaust heat for a fuel cell energy network (FEN), in which fuel cells installed in two or more buildings are connected, was considered. A program for planning the path for the hot-water piping network was developed in this study, and it can be used to plan the route which minimizes the amount of heat released in the piping considering the difference in temperature of the open air and hot water. In the plan of the hot-water piping network in the FEN, the energy demand pattern in each building and the electric power generation capacity of the fuel cell installed in each building confirmed the optimization of the hot-water piping path as a result of the analysis. Furthermore, when fluctuations in the electricity demand in each building linked to the FEN are large, the optimal path of hot-water piping differs from the case where there is no change in electricity demand.

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The amount of energy demands tends to increase in the commercial sector, and the energy management has been an important issue to design, operate, and control energy supply systems. In this paper, a framework for the operational management is presented by utilizing optimization and simulation techniques comprehensively. The operational management requires energy demand prediction, optimal operational planning, optimal control, and dynamic analysis. Optimization techniques to identify the values of parameters for prediction and dynamics models as well as to determine the operational and control strategies of energy supply systems are presented. In addition, simulation techniques to analyze the static and dynamic behaviors of energy supply systems are presented.

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We expressed an energy supply system by means of object-oriented modeling with UML (Unified Modeling Language), and then developed a simulation program written in JAVA. It aims at the construction of the simulation program with various models having flexibility by adding and changing environment, demand, and equipment information. The design and the operation of the cogeneration system in SFC (Shonan-Fujisawa campus of Keio University) were simulated using the partial load performance of the actual co-generation system. The consumption of primary energy source, demands of thermal and power energy were correctly reproduced by the program and the calculation in the case of energy supply system without the co-generation system showed the 14% elimination of primary energy resource and 22% CO_2 reduction by introducing the cogeneration system in the SFC.

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It is an extremely difficult task to determine equipment capacity of co-generation systems according to electrical-power and heating demands while taking into account economic efficiency and environmental load Given that background, this paper describes a design method for a co-generation system that minimizes the payback period by utilizing the Hamiltonian algorithm. This algorithm performs optimization of the non-linear systems used in the information and communication fields. As regards the result of a study on introducing a co-generation system into a combined building hosing offices and a hotel, by using the algorithm to select machinery capacity and operating methods, it was possible to shorten the payback period by about a year.

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This paper presents mapping method to show characteristics of cogeneration systems (CGS) for the reduction of carbon dioxide emission and economy. In this method, effects of CGS can be consolidated into rated reduction ratio, relative reduction ratio map, demand repetition map and weight map. By lapping these maps, it can be easy to evaluate compatibility with each building types and optimal installed capacity. Analyzed charts are useful to evaluate quantitative effects of CGS for various areas and price rates of electric/gas from average annual demand of electricity and heat.

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This paper presents the study of a monitoring and assessment for energy supply system of public facility with Co-Generation System (CGS). Recently, CGS is expected as one of the measures for global warming. However, there are many cases that the actual operation conditions of the energy supply system, like CGS are uncertain to practice to the energy saving at the facility. Then, we focus to public facility with CGS, and investigate the energy supply system. A monitoring and assessment are done in a certain hospital CGS. Concretely, total energy available efficiency of CGS are calculated by monitoring the heat balance in CGS. And we showed the comparison result with measurement value by applying various CGS assessment method and standard.

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General concept of small distributed energy plants remarkably begins to establish both of high energy saving and space saving effects. Numbers of examples with their systems are increased year by year, especially urban areas, however, it always cannot be the same in local areas. They may be based on the actual effects related with peculiar weather conditions of each districts. This study shows the performance of co-generation system operated by MGT in a snowy and cold area. This co-generation system was tested with digestive gas, produced in a fermenting gas tank of a sewage plant. Especially in cold circumstances, most of co-generation energy was forced to exhaust to heat up the tank, since it needs to keep the digested sludge temperature over 39℃. In this case, it is also indicated that yearly smoothing method for electric power production was strongly needed, since there are much methane fermented in summer but decisive lack of heating energy from MGT was encountered in winter.

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The study investigated the effect of daylight-responsive lighting control on the optimum capacity of gas engine cogeneration systems. The heating and cooling loads of an office building were calculated by an energy simulation software EnergyPlus. Then, the energy consumption of the energy supply system including the grid, gas engines, boilers, and electric and absorption chillers was simulated by a program developed by the authors. It was shown that lighting control considerably increased the heat to power ratio of the demand, which would affected the operation and the energy savings of the cogeneration system. The energy savings by lighting control was predicted as 14%, and that by cogeneration was 7%.

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The performance characteristics were investigated of three high-efficiency gas-engine generators with capacities of 300 to 400kW and two groups of the "Genelink", i.e. exhaust heat recovery absorption water chiller-heater, as main components of cogeneration systems, CGS. Next, computor simulations were made on the CGS in order to evaluate monthly and annual primary energy consumptions and CO_2 emissions for such building use as office, shop, hospital and hotel with ordinary electric, cooling, heating and hot water supply loads. Then, the optimum conditions for application of CGS were discussed from energy saving and environmental points of view.

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[in Japanese]

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Solid oxide fuel cells (SOFC) are expected to become a primary power supply component in distributed energy systems. In addition, the fuel flexibility of SOFCs is attractive for the small-scale distributed power generation driven with biomass derived fuel. In this paper, the performance evaluation of a biogas fueled micro gas turbine (μGT)-solid oxide fuel cell (SOFC) combined power generation system is investigated by using thermodynamic cycle simulation. The power generation characteristics of methane and hydrogen fueled hybrid systems are performed as reference cases. At the SOFC operating temperature of 800℃ and the pressure ratio of 3.0, the efficiency values of the methane fueled system and the hydrogen fueled system are 59% and 51% (LHV), respectively. The data of biogas compositions are extracted from the previously reported work regarding the fuel cell operation with biogas from farming waste/sewage and a wood gasification process. Throughout the simulation, it is found that the fuel compositions significantly affect the system performance. Higher methane content in biogas causes the higher efficiency of a hybrid system, because an internal steam reforming of methane operates effectively upon the efficiency improvement of a hybrid system. In the case of hydrogen fuel, excess heat of a cell stack is solely used for fuel pre-heating. Consequently, much air is required for cell stack cooling, and the fractional power output of a μGT becomes larger. Higher ratio of μGT power to total power leads lower efficiency. This means that the utilization of hydrogen rich fuel degrades efficiency. The system optimization, which includes biomass fuel production processes, is essential for the development of much highly effective hybrid systems.

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The alkali metal thermal to electric converter (AMTEC) is a device for the direct conversion of heat to electrical power. Operating hot-side temperatures of AMTEC cells are well compatible with those of solid oxide fuel cells (SOFC), so that the stacks of the SOFC can be directly coupled to hot-side of the AMTEC cells. The AMTEC cells would produce electrical power from released heat of the SOFC, as well as control the SOFC operating temperatures by modulating current of the AMTEC cell. A new honeycomb type AMTEC cell is discussed in this paper. The cell uses advanced beta"-alumina solid electrolyte (BASE) configurations to improve the device performance over the conventional tube BASE systems. Expected power densities and efficiencies were calculated. The influence of temperature differences between heat source and anode side electrode is also discussed for vaper-fed type and vaper-vaper-fed type cells.

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Recently, development and the spread of environmentally-friendly and high-efficiency single-seat fuel cell electric vehicle are expected. Then, in order to up-grade a fuel cell electric vehicle, we participated in the fuel cell section established in energy saving competition "World Econo move (WEM)". We simulated for the best running condition by experiment, and carried out test run to prove its performance. As a result, power consumption was improved by regeneration, and thereby about 1.56km extension of the cruising range was achieved compared with the year before run.

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Recently, development and the spread of small, lightweight, environmentally-friendly and high-efficiency single-seat fuel cell electric vehicle are expected. Then, in order to realize this concept, we designed and manufactured for ULFCV (Ultra Lightweight Fuel Cell Electric Concept Vehicle) applying the development technology of competition vehicle. In this paper, to realize more practicability, we considered the power system of the ULFCV by designing new type high powered motor and selecting best available fuel cell and capacitor.. We confirmed the ascending performance by doing test run on the public road and at Honjo campus of Waseda University. As the result, we're able to achieve the driving of 14%. slope. In addition, 46% reduce of light energy was achieved by making lights by LED.

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A UPS with an energy storage function using long-cycle-life VRLA batteries has been developed. Combining the functions of UPS and energy storage is effective to enhance the cost-effectiveness of the UPS. New long-cycle-life VRLA batteries, with capacities of 1000 or 1500 Ah at 2V, have been developed for the UPS. A cycle life of 3000 or more cycles was estimated from our cycle test. The UPS has been installed in a telecommunications building for field testing. This paper describes the system configuration, electrical characteristics of the UPS and its components, and result of our field test.

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Reliable Helmholtz thermodynamic equations of state for important refrigerants, R143a, R32+R125, R125+R143a, R600, and R600a, are developed. The blended mixture of R32+R125 is used in air-conditioning systems as R410A, and R600a (iso-butane) is a refrigerant in domestic refrigerators. Those equations of state are developed as our final results from long experience of developing thermodynamic equations. The characteristics are that those equations can derive reliable specific heat values near saturation in the gaseous phase by using virial coefficients based on theoretical model of intermolecular force, and the thermodynamic surface covering all the fluid phase behaves reasonably from viewpoint of physics. It was confirmed by examining the ideal curves especially at high temperature and pressure phase. Those equations will provide the best property values for those substances. This report introduces several features of those equations of state.

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In the residential application, a CO_2 heat pump is used in combination with a hot water storage tank, and the performance of this system is affected significantly not only by instantaneous air and feed water temperatures but also by hourly changes of hot water consumption and temperature distribution in the hot water storage tank. In this paper, the performance of the system is analyzed by numerical simulation. A simulation model is created based on thermodynamic equations, and the values of model parameters are estimated based on measured data on existing devices. In a case study, the heat pump COP, storage tank and system efficiencies, volume of hot water unused, etc. are selected as criteria for system performance, and it is clarified how they are affected by seasonal changes of air and feed water temperatures.

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The temperature of sea water is lower than the outside air temperature in summer, and higher than the outside air temperature in winter. Therefore, high energy efficiency can be obtained by utilizing sea water for heat source water or cooling water of heat pumps. Then, we had developed the highly effective heat pump, which can use sea water directly as heat source or cooling water. In the Port of Nagoya Public Aquarium, the water temperature of huge pools for breeding orca, belugas, etc., is adjusted with this highly effective heat pump system. In this paper, the energy-saving performance and environmental preservation performance of the system are clarified by analyzing the operation data over a period of four fiscal years.

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Thermosyphon are heat transport devices that can transfer heat using gravitation. They can work without any external power supply, and have simple structures. Recently, a device which transfers heat from the hot reservoir on the top to the cold reservoir in the bottom was made and investigated the performance by Ippohshi and et.al. In this paper the same type of device and another type of device which was simpler in the structure were made and their performances were compared with each other. It was found that the one made later did not take time before the water in the tube circulated. The apparatus could transport heat up to 290W for the water at temperature of 25℃ in the cooler. The effective thermal conductivity of the tube was in the range between 10^4 and 2×10^5W/(m・K).

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This paper deals with characteristics of falling film absorber and condenser in the bottoming cycles which employ ammonia-water mixture as working fluid. The authors constructed a unique co-generation system, named ACGS, at the campus and are investigating various kinds of energy saving technologies under practical situations. ACGS has the power and the refrigeration cycles using ammonia-water mixture as working fluid at the bottoming stage. The absorber and the condensers largely affect the performance of both cycles. It is necessary to investigate the absorption process detailed condition for designing the absorber and condenser, because the condensation with absorption process of mixture is more complicated than a single medium. Then, liquid film condition of condenser was calculated with finite difference analysis. It shows the mass fraction distribution and temperature distribution, and the number of tubes and the tube length filled operating point.

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Ammonia absorption refrigerator is an energy conservation equipment that can be driven by waste heat comes from primary generators in cascade. Some of the challenges for the ammonia absorption refrigerator are high efficiency, low-cost, and lowering the heat source temperature. The authors have been shown that lowering the ammonia mass fraction of the refrigerant makes the heat source temperature. This paper reports some results of experimental investigations on an ammonia absorption refrigerator to confirm the validity of our theory. The experimental refrigerator is a single-stage absorption refrigerator of 350[kW] cooling capacity. The rating heat source temperature is 161[℃] and the refrigerant mass fraction is 99.8% at the top of the rectifying column. Experimental investigations are carried out with a parameter of the temperature at the top of the rectifying column which determine the ammonia mass fraction of the refrigerant.

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Recently, dehumidification becomes very important in the air-conditioning for amenity and health. An open cycle absorption type dehumidifier using LiCl-solution can be driven by low grade waste heat, and adjust the temperature and humidity at the same time. This dehumidifier is effective for energy savings and easiness of temperature and humidity adjustment. However, detailed evaluation of characteristics of the system has not been investigated. In this paper, the performance of an open cycle absorption type dehumidifier using LiCl-solution is evaluated by the simulations. As a results, COP is about 0.88. And the energy used for dehumidifying is constant regardless of the temperature of the heat source.

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A novel home cogeneration system that is available to air conditioning use has been proposed, and its feasibility has been investigated theoretically. Waste heat from PEFC that is used as a generator is usually utilized as a hot water in micro cogeneration. But, in Japan, in order to reduce increasing power consumption for air conditioning in residential use, it is indispensable to develop a home cogeneration system that can be used for air conditioning. Therefore, a single effect absorption chiller heater was adopted as waste heat recovery equipment. The absorption chiller heater is driven by the low temperature waste heat from the PEFC and is available for air conditioning. Their performances and efficiencies were predicted quantitatively by computer simulation. Furthermore, air conditioning performances of the absorption chiller heater were calculated with considering real weather conditions and were cleared for cooling water temperature changes.

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The adsorption chiller generates chilled water by adsorbing and desorbing low-pressure coolant water. Considering saving energy, adsorption refrigeration system can be driven by waste heat at near ambient temperature. Unfortunately, this system only works on a large scale due to poor performance. In order to improve performance, it is necessary to accelerate the adsorption velocity and equilibrium adsorption by conducting the heat to silica gel in a short time. In this study, we applied the heat transfer plate coated adsorbent in order to enlarge a contact surface adsorbent on the heat transfer plate. This study aims at the rise of adsorption velocity, and comparison with the conventional. From the experimental result, it is shown that heat transfer plate coated adsorbent has higher adsorption velocity, and the porous media with short diameter holes (20nm) has higher adsorption velocity than the porous media with long diameter holes (60nm).

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A basic study of improving concentric tube heat exchanger was conducted. A design was adopted in which the inner tube with a multi-lobe shape inserted into the outer tube touching with its outward-most tip tightly attached to the inner surface of the outer tube. This design aims to increase the heat convection area between the inner and outer fluid passage while keeping flow resistance low. To bring out the best of this design concept, inlet shape optimization and suitable clearance between the inner and outer tubes were studied by computational fluid dynamic modeling. The deformation under high-pressure difference was estimated by finite element analyses.

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