Usual thermosyphons can only transport heat, from lower to higher positions because they utilize the gravitational force for condensed liquid to flow down from an upper condenser to a lower evaporator. On the other hand, top-heat-type thermosyphons must employ some means to pump up the condensed liquid from the lower condenser to the upper evaporator without consuming any power from outside. In the present report, we first describe the design points of usual heat pipe and thermosyphon, and secondly, as the main subject of this report, review the studies on the top-heat-type thermosyphons which have been published so far. Especially, we pick up four kinds of the top-heat-type thermosyphons and explain briefly about them, because they seem to have more practical applicability.

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The method of supplying the electric power and heat energy for the energy demand of buildings by Centralized system type and distributed system type of fuel cell network is studied. The hot-water piping route planning program of fuel cell network was developed by using genetic algorithm based on the view of TSP ( Traveling salesman problem) . In this program, the piping route planning which minimizes the quantity of heat loss in hot-water piping can be performed. The residential section model of Sapporo city of 74 buildings was analyzed, and the quantity of heat loss from the hot-water piping of both systems was estimated. Consequently, the ratio of the quantity of heat loss of a distributed system to a centralized system was about 50% in the full year average. This program is introduced into the route planning of hot- Water piping system of the fuel cell network, and plan to reduce the quantity of heat loss in a distributed system will be made.

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Recently, there is an important subject to reduce of the CO₂ emission discharged from a building. A cogeneration system (CGS) is one of the effective facilities to reduce of the CO₂ emission, but prudent consideration is required in design and operation. Because it is necessary to be matching electric demand and heat demand in order to obtain the high efficiency. In this paper, it is evaluated the power generation efficiency and heat recovery one of CGS in the actual urbanized hotel as measurement result. In addition, the optimal operation analysis is carried out in order to minimize CO₂ emission in the present facility.

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A double-stage regeneration concept has been applied to a rotary dehumidifier to achieve a high efficient desiccant cooling process. In this concept, regeneration zone of the dehumidifier was divided into two zones. One was pre-regeneration zone where the desiccant rotor was regenerated by warm air heated at the sensible heat exchanger, and the other was heating regeneration zone where the rotor was further regenerated by hot air heated up to the controlled temperature at a heating system. In this paper, the influence of the area ratio of these two zones on the dehumidifying/cooling performance and energy efficiency of this desiccant system were mainly discussed at several levels of the regeneration temperature, supply air velocity and inlet air humidity. Experimental results indicated that the area ratio of the heating regeneration zone should be optimized to produce a sufficient dehumidifying/cooling performance with high energy efficiency, considering humidity requested in supply air. It was also found that the amount of energy input was rather decreased than the decrease of the cooling performance as the area ratio of the heating regeneration zone decreased, and this tendency was more remarkable at higher regeneration temperature. Finally, the double-stage regeneration was confirmed to be an effective operating method for the desiccant cooling process equipped with a otary dehumidifier.

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These days the environmental impact due to vending machines'(VM) diffusion has greatly been discussed. This paper describes the numerical evaluation of the environmental impact by using the LCA (Life Cycle Assessment) scheme and then proposes eco-improvements' strategy toward environmentally conscious products(ECP). A new objective and universal consolidated method for the LCA-evaluation, so-called LCA-NETS(Numerical Eco-load Standardization ) developed by the authors is applied to the present issue. As a result, the environmental loads at the 5years' operation and the material procurement stages are found to dominate others over the life cycle. Further eco-improvement is realized by following the order of the LCA-NETS magnitude; namely, energy saving, materials reducing, parts' re-using, and replacing with low environmental load material. Above all, parts' re-using is specially recommendable for significant reduction of the environmental loads toward ECP.

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In this study, the fundamental characteristics of ice slurry which is used for the dynamic type thermal energy storage system were investigated experimentally. Propylene glycol solution was used a thermal energy storage material. The ice slurry was produced by release of supercooling condition of the solution, while the solution was stirred. Then, the degree of supercooling and the concentration of the solution were varied as the parameter, and the observation of ice crystal right after the generation were carried out. The ice slurry after storage for several hours in the solution and the air was also observed to examine the variation of the characteristics of the ice slurry due to the storage. Moreover, the latent heat of fusion of the ice slurry was measured, and the relationship between the effective latent heat of fusion and the heat of dilution were revealed. These examinations were performed for ice slurry produced from another solutions which were ethanol solution and ethylene glycol solution, and the characteristics of the ice slurry were compared with each other from the viewpoint of the thermal energy storage material.

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A method to making ice slurry is one of key technology for cold-energy Storage system. This study has been conducted to clarify continuous production of ice slurry by utilizing constitutional supercooling promoted by mixing of two aqueous solutions whose solute concentrations are different. In this technique, fine ice crystals are made under volume-catalyzed nucleation without heat transfer surface. In the experiments, cooled sucrose solution and water were mixed in the cylindrical vessel, and ultrasonic vibration was applied to promote nucleation in the supercooled solution. It was found that the ice making process is classified into three characteristic patterns; stable ice making, ice making in stratified concentration layer due to defect in solute-mixing, and no ice making due to no supercooling by mixing. The characteristics of ice making were discussed with the mixing ratio and total flow rate of solutions.

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The experiments and calculations were carried out to evaluate the cycle performance of natural circulation loop with CO₂. The cooling capacity of CO₂ was compared with that of R410A and the cooling capacity of reverse circulation observed under the supercritical condition was analyzed from a point of view of refrigerant flow direction. The experimental results showed that the cooling capacity of CO₂ was approximately4∼13% larger than that of R410A under the two-phase condition at indoor temperature of 30°C. On the other hand, the cooling capacity of CO₂ was approximately11% smaller than that of R410A under the supercritical condition at indoor temperature of 50°C. In addition, the cooling capacity with the counter-cross flow heat exchanger was approximately 40% larger than that with the parallel-cross flow heat exchanger under the supercritical condition at indoor temperature of 50°C. These experimental results agreed well with the calculated results.

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For the absorption of water vapor into the aqueous lithium bromide solution, eight-carbon alcohol additives such as 2-ethyl-1-hexanolhave been commonly used to improve the absorption process. However, as additives six-carbon and seven-carbon alcohols were not been tested experimentally very much. In present study, absorption of water vapor into the 62 wt% LiBr solution with several six-carbon and seven carbon alcohol additives such as 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-hexanol, 2 , 4-dimethyl-3-pentanol, 4-heptanol, 2-heptanol and 1-heptanol were investigated by using a simple stagnant pool absorber. Besides using the conventional method which mixing additive into LiBr solution, vapor phase adding method was experimented. Surface tensions of aqueous LiBr solution with different surfactant also were measured by Welhelmy plate method. Absorption of water vapor into the LiBr solution with 2-ethyl-1-hexanol and 1-heptanol were also experimented in falling film absorber by vapor phase adding method. The result showed that the lower the surface tension of LiBr aqueous solution with an additive, the better the effect of absorption enhancement by the corresponding additive, and vapor phase adding method is effective for the absorption of water vapor into the LiBr aqueous solution.

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