This report describes the development of a hybrid heat pump in order to utilize low temperature unused energy. This hybrid heat pump consists of topping part and bottoming part in order to realize heat cascading of natural gas, which is expected to play major role in future energy sources in Japan. A gas engine driven heat pump plays the topping part and adopts non-azeotropic refrigerant in order to realize Lorenz cycle. An adsorption chiller plays the bottoming part energized by the waste heat of gas engine heat pump and the sensible heat of heat pump refrigerant. A new device measuring the amount of water absorbed was developed and theoretical COP was calculated on the basis of these experimental data.

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The removal of nitrogen compounds in wastewater has been required formerly by even to the small-scale onsite household wastewater treatment facilities. This experimental study aimed to confirm on the some planning factors in biological denitrification process for such facilities. This paper stated on the following items. 1. Mutual relations between pH, ORP values and nitrification/denitrification reaction. 2. Required and desirable characteristics of the influent and recirculating water. 3. Interaction between recirculation ratio (quantity) and denitrification degree. The following results were obtained in this experiment. It is desirable to keep about over +200mV ORP for nitrification process, and under about +50mV for denitrification process. Adequate recirculation Ratio will be about 4.

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There has been a growing awareness of the importance of conserving fossil energy resources and developing the techniques of passive heating/cooling systems in buildings which utilize natural sources of energy and the natural environment. It's necessary to investigate the possibility of passive cooling in summer as well as passive heating in winter. One technique of passive cooling, water evaporative cooling is considered to be promising. This study deals with water evaporative cooling by means of roof spraying. From the standpoint of saving water in roof spraying systems which use a minimum rate of water with no water recovery system, the optimum rate of water supply in roof spraying was examined experimentally through the use of wooden experimental structure. The experimental structure was designed so as to enable insulation properties of the walls, roof and floor to be controlled through the replacement of insulation materials. This paper describes the estimated optimum rate of water supply of roof spraying systems in various areas of Japan, by using the experimental results. Analyzing the relationship between the calculated evaporation rate and measured rates of supplied and returned water for experimental structure statistically, the regression line can be derived, which is used to calculate the required rate of water supply in roof spraying. Then a method is developed, which revises the required rate of water supply for various shapes of the roofs, using the parameter of L/S. Here L is the outline length [m] of a roof and S is the sprayed roof area [m^2], which can be covered by one sprinkler. After analyzing the regression line and the calculated evaporation rates in various areas of Japan, the required minimum rates of supply water in various parts of Japan were estimated, which are for roof spraying systems with no water recovery.

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Heat loss from hot water in intermittently used supply pipeline, which is common in residencial building, was studied by numerical calculation. After checking the accuracy of the calculation method, the calculated heat losses were compared with those calculated by the approximated method proposed by Yoshino. As the results, it became clear that Yoshino's method overestimates the heat losses. However daily mean heat loss can be estimated within 2 or 3% of relative error by the approximated method. Moreover the economical thickness of thermal insulation material are considered. As the results, it became clear that the economical insulation thickness is 1/5〜1/10 of that of the continuously used hot water supply pipeline.

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This paper describes the follow-up investigations on three cases by using the planning and design method established in the author's preceding paper, in which breakthrough curves were obtained and hence breakthrough times determined for acid, alkali and neutral gases, respectively. On the other hand, the lifes were calculated by using the equation given in the author's preceding paper, and then compared with the breakthrough times obtained from the breakthrough curves. As a result, it was found that the calculated lifes were in fairly good agreement with those obtained from the breakthrough curves for acid, alkali and neutral gas adsorbents, respectively.

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A road heating system with air source heat pumps using waste heat from subway was completed in December 1987 at Sapporo-city. When the subway service is out in the midnight time, the system operates without taking waste heat from the subway. This paper evaluates the quantity of heat recovered from underground structures during the subway service out time. From the measured temperature data, the following items are clarified; 1) thermal energy stored in the structures of subway in summer and that radiated in winter season 2) in one-dimensional analysis, 0.00025m^2/h of temperature conductivity shows good agreement with the measured data of temperature distribution in the structures of subway 3) heat pump inlet air temperature rise up is evaluated for about 2〜3℃ comparing to the condition with no heat recovery 4) this temperature rise gives COP increase of 0.14 and power out put increase of 7%.

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A new snow-melting system was developed. This system uses the geothermal energy collected by building piles with circulating water, and is controlled by a snow cover sensor. In the experiment, the snow covered on the concrete-surfaced test section of 20.8m^2 area was melted by the thermal output from two concrete piles of 0.31m inner diameter and 22m length. And it is demonstrated that this snow-melting system operates effectively for the intermittent snow-fall condition in relatively warm areas. Namely, the test section was kept no snow-staying condition during the experimental period (Jan. -Mar., 1991) where we had accumulated depth of snowfall of 187cm and maximum thickness of snow cover of 60cm in Fukui city. The numerical simulation was also made to evaluate the system, where the piles and the heating pipes buried in the concrete-surfaced test section were treated as a connected system. The thermal output from a pile and the heat value collected from the surrounding soils were calculated. Furthermore, temperature profiles of water in the pile were shown for the snow-melting process and the heat recovery process. The comparisons of the numerical results with the experimental ones show good agreement for two examples of different conditions of snow-melting area and flow rate of water in the pile. It is concluded here, that the simulation method described in this paper is useful for designing the said snow-melting system.

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Following Part 1 of the report which made clear the general problems of present hot water supply systems for housings from aspects of their use of hot water, a questionnaire to obtain data on the present status of hot water usage and thermal emvironment and such of bathrooms and dressing rooms including differences among areas of Japan was conducted. There were 70 questions in the questionnaire and was carried out in the six areas of Sapporo, Fukushima, Tsukuba, Tokyo, Nagano, and Nagoya. The period was during January and February in 1989 mainly and the number of effective questionnaires returned was 664. From the viewpoints of 1. object and length of time of bathing and the number baths taken 2. method of heating water and time required usage of used water and its purpose 3. water temperature 4. air temperature of the bathroom and the dressing room 5. ventilation of the bathroom 6. area of the bathroom and the dressing room 7. volume of the tub and the height of the edge of the tub (which one must step over in order to get into the tub) and such, the results were analyzed and studeid including comparisons with results acquired from previous researches for setting required standards for the hot water supply system for housings.

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Experimental set-up adsorption chiller was developed in order to aquire basic data of adsorption cycle. In order to enhance overall heat transfer coefficient, a newly developed adsorption bed using aluminized plate, fin heat exchanger was adopted. After obtaining several design data including overall heat transfer coefficient, a proto-type machine was produced and capacity, COP and temperature characteristic were measured. These data successfuly enables us to design and produce highly efficient adsorption chiller (COP=0.66).

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It is necessary to measure soil thermal properties in many engineering projects where heat transfer takes place in soils. This paper deals with actual changes of thermal properties of soils caused by freezing and melting and a method for calculating the thermal conductivity of frozen and unfrozen soils. Amount of unfrozen water contents in five kinds of soils, which were sand, volcanic ash, garden soil, clay, ground surface soil, was measured by the pulsed NMR method. The decrease in unfrozen water contents could be expressed as a function of temperature given by the exponential equation. The thermal conductivity was measured by using the thermal probe method. We have investigated its change due to temperature variation in the case of cooling process (including freezing) and heating process (including melting process). The difference between these two processes was little and the values after freezing and melting returned to the initial ones. Thermal conductivities of frozen soil were greater than those of unfrozen soil. There was the largest difference between values of unfrozen and frozen soil in sand with little unfrozen water existence among these five kinds of soils. A method for calculating the thermal conductivity of frozen soil was proposed. It is extended from the three elements method above 0℃ and subdivided into four constituent elements, which consist of soil particle, ice, air and unfrozen water. Evaluated thermal conductivities were generally corresponded well to measured values on these five kinds of soils.

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