The most important theme for heat pump air conditioners is the improvement of energy saving and comfort. Recently, cycle components, especially compressores and heat exchangers have been improved greatly in their performance and efficiency. As for compressors, large progress in their efficiencies have been made by detailed analysises such as mechanical losses and by the development of a new type compression mechanism. As for heat exchangers, various high heat transfer surfaces have been developed together with the improvement of the production technologies for them. Further, the effect of the capacity-modulated cycle is evaluated quantitatively through the improvements of static and transient cycle simulation technologies. And in order to realize this cffect, the electrically driven expansion valves heve been marketed. This review introduces the trends of these energy-saving technologies as well as comfort improvement studies.

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This paper deals with the heat transfer characteristics when a phase change medium discharges the storing energy to a finned tube in a heat storage container.
In this experiments, the phase change medium is Calcium Chloride Hexahydrate (CaCl₂6H₂O)with fusion temperature 28°C. The following results are obtained.
1. In solidification process of the medium, the heat discharge quantity to a finned tube is greater than that to a single tube, However, the heat dischage quantity of the finned tube does not increase inproportion to the surface area of the fin.
2. The fin effect of the finned tube decreases as the increase of the accumulative heat discharge quantity rate.
3. This reason lies in the fact that the thermal resistance of the finned tube is greater than that of the single tube. Especially, in the range of the large values of the accumulative heat discharge quantity rate, it is consiberable that the themal resistanse increases so that the ratio of the dead space of the heat transfer area increases at the contact parts of the fins and the tube.

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A pipe cooling method using chilling unit has been developed, which is capable of controlling the temperature of massively placed concrete.
The thermal analysis is conducted for the design of this method to the practical concreting work. The Finite Differential Method (FDM) has been employed to calculate the concrete temperature and the cooling capacity.
Thermal constants of concrete are determined by room experiments in simulating cooling conditions. The differences between calculated results and measurements obtained under practical concreting work are 2°C in temperature and in capacity of 10%.
It is found that this method is able to control the concrete temperature with high accuracy and to be used sufficiently for a field practice.

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The dielectric constants of six refrigerants have been measured in both gaseous and liquid phases. The fluids used and the experimental ranges of temperature and pressure are as follows :
R113 (1, 2, 2- Trichlorotrifluoroethane CClF₂CCl₂F) : 298.15-423.15K, 0.1-17.3MPa,
R1l4 (1, 2- Dichlorotetrafluoroethane CClF₂CClF₂) : 298.15-423.15K, 0.2-17.2MPa,
R114B2 (1, 2- Dibromotetrafluoroethane CBrF₂CBrF₂) : 298.15-423.15K, 0.2-17.3MPa,
R1l5 (Chloropentafluoroethane CClF₂CF₃) : 298.15 373.15K. O.1-17.1MPa,
R1l6 (Hexafluoroethane CF₃CF₃) : 283.15-373.15 K, 0.2-16.9MPa,
R124 (1-Chloro-2, 2, 2, -tetrafluoroethane CHClFCF₃) : 273.15 373.15K, 0.1-10.5MPa
The measurements were performed using a frequency-counting method on a relative basis with an uncertainty less than ±0.1%.The experimental results are given by polynomial equations. The smoothed value tables are also given for practical convenience. The pressure dependence of dielectric constants in liquid phase is represented by a similar expression to the Tait equation. The effects of pressure, temperature, and density on the dielectric constant and the molar polarization defined by the Clausius-Mossotti relation are discussed in term of polarity of molecules of each refrigerant.

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Present paper describes the starting point of solidification at supercooled conditions of aqueous solution. Experiments were carried out on the freezing of large numbers of liquid droplets of aqueous solution of NaCl, ranging from 1mm to 4mm in diameter, from 5wt% to 15wt% in concentration and from 3.33×10^-3 to 9.20×10^-3K/s in cooling rate and suspended at two immiscible fluids. The relation between the concentration, the degree of supercooling, the cooling rate and the diameter of liquid droplets was experimentally arranged in exponential function by using probability of freezing. Observation of freezing process reveales that freezing rate decreases with the concentration.

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A field experiment was carried out in Kushiro, Hokkaido during 1982-1984. The heat pipe, which was 0.1m-diameter, 11m-length (8m under the ground) and 14.5 m²-fin area for condence, was designed for pumping cold from the surrounding cold air into the earth. R-22 was used as working fruid.
It was, recognized that (1) soil surrounding the heat pipe was frozen about 80 cm-diameter for one winter with about 500 degree days of frost, (2) cold energy about 4.5×10⁴kcal per 1m of the heat pipe was stored in this frozen soil and in unfrozen soil around it, and (3) the temperature difference between the air and the evaporator of the heat pipe was only several degrees.
In this paper, some of the design and the efficiency of the heat, pipe are reported and a method is proposed for keeping a large mass of frozen earth all the year.

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Flat Panel evacuated porous insulators have been produced by filling powder or fiber (such as perlite powder, diatomaceous earth powder, silica aerogel powder, g lass fiber and ceramic fiber) in film-like laminated plastic container and by evacuating to form vacuum in it is interior. Heat transfer properties of these evacuated insulators have been studied under various conditions (such as particle diameter, surface area, packing density, solid volume fraction and void dimension).
The apparent mean thermal conductivity has been measured for the boundary surface temperature at cold face temperature 13°C and hot face temperature 35°. The effect of air pressure ranging from 1 Pa to one atomosphere (10⁵ Pa) was examined. The results were as follows.
(1) For each powder the apparent mean thermal conductivity decreases with decreasing residual air pressure, and at very low pressure bellow 1 -103 Pa the conductivity becomes indeqendent of pressure. The thermal conductivity at 1.3Pa is 0.0053 W/mK for perlite powder, 0.0048W/mK for diatomaceous earth powder, 0.0043 W/mK for silica aerogel powder and 0.0029W/mK for glass fiber.
(2) With decreasing particle size, the apparent mean thermal conductivity is constant independent of residual air pressure in higher pressure region. It is that void dimension continues to decrease with particle size and the mean free path of air becomes comparable with void dimension.
(3) In the range of minor solid volume fraction, the apparent mean thermal conductivity at very low precreases with decreasing particle size. This shows the thermal contact resistance of the solid particle increases with decreasing particle size.

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Quality change of frozen horse-mackerel were studied under storage temperature at -18, -23, -30 and -40°C for 12 months. Quality were measured with K value (Freshness index of muscle, degradation ratio of ATP), amount of drip (free and expressible drip), water-holdiog capacity, weight ratio of cooking loss, organoleptic test, and histological feature of muscle.
K value, a mount of free drip, w eight ratio of cooking loss, histological feature of muscle, and organoleptic test in color, form and flavor were not detected any changes during frozen storage for 12 months at various temperature. However expressible drip, water-holding capacity and score of taste in organoleptic test showed some changes after 8 or 12 months at -18 and/or -23°C, it was not serious change to-loss quality as food. Frozen horse-mackerel can store under below ~ 18°C for 12 months.

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In the range from below-zero temperature to termination temperature of evaporation, the thermal conductivity and the thermal diffusivity during a heating process are measured successively by the modified hot wire method and by the continuous heating method, respectively.
It is found by the numerical experiment that the location of the thermocouple at the wall side should be measured accurately although it does not matter if the thermocouple near the center of the specimen deviates slightly from the original location. The measured results are independent of heating rate whose experiments are made by the above two methods for packed beds of glass beads and of aluminum oxide at heating rate of 0-0.05K/s from room temperature to 800K.
The thermal conductivity for cross grain of wood(φ20×100mm) is larger than that for straight grain of wood by about 30%, both of which are heated at 3K/min after keeping for about 3h ours in the refrigerator(240K). There is not much difference between the thermal diffusivities of two kinds of woods. The thermal diffusivitiy of wood decreases considerably by the evaporation latent heat. The effective thermal conductivity of packed bed of coal (apparent density is between 730 and 1030 kg/m3 and particle diameter is under 3.3 mm) increases with temperature, moisture content and apparent density. The packed bed of coal is kept for about 20 hours in the refrigerator, heated at 3K /min during heating process and cooled at -3 K/min during colling process. The effective thermal diffusivity of packed bed of coal decreases near the freezing point and increases with moisture content. The measurement error of the thermal conductivity and diffusivity of wood and coals is within ±4% as a result of three times measurements for the same condition except for the packed bed of coal near the freezing point where the measurement error counts up to ±20%.

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Ark shell, Anadara broughtonii(Shrenk), are commonly eaten raw or under-done in Korea, Japan, and East Asian countries. Along with a recent remarkable development of culture fisheries, Ark shell has become one of the commercially important shell-fish species. Transportation and storage of large quantities of shell-fish is becoming increasingly important. This work was begun with this background to make clear the effects of temperature and length of storage time on the quality of frozen stored ark shell.
Results are as follows :
(1) There was little chang in amounts of free and expressible drip from ark shell flesh frozen stored at -40°Cdeg;C for 6 months. Water holding capacity of the same meat was almost constant over 6 months storage. However, a mounts of both drip increased markedly after 2 months storage at -10°C.
(2) Protein extractibility of ark shell flesh tended to decrease gradually from the begining when stored at -10°C, while at -20°C, the protein extractibility was stable for 3 months before decreasing gradually. However at -40°C, the protein extractibility was stable for 6 months. It was found that paramyosin was very stable even when the ark shell was frozen stored at -10°C.
(3) It was observed that ark shell flesh became tough when frozen. The toughness of ark shell flesh as measured by an instrument increased with frozen storage time and increased temperature.
(4) In the smooth muscle, it was histologically observed that initial small ice crystals formed between muscle bundles grew larger during frozen storage. It was found that the higher the storage temperature, the bigger the ice crystals formed. Aggregation of some muscle fiber and empty spaces between muscle bundles were observd after thawed muscles frozen stored at relatively high temperature such as -10°C.

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The recent development of absorption-type heat pump is highly essential from the viewpoint of extracting the effective energy from waste heat or solar energy. To increase the efficiency of energy conversion, it is important to improve the performance of absorbers.
The objective of this paper is to obtain an increased understanding of the fine mechanisms of vapor absorption. A system combining holographic interferometry wity thermometry is adopted to observe the progress of one-dimensional water vapor absorption by aqueous solution of lithium bromide (LiBr) and also to measure the unsteady temperature and concentration distributions in the absorption process. The experiments are carried out under the condition that the solution surface is exposed to the saturated water vapor at reduced pressure, and the effects of LiBr mass concentration on absorption mechanism are examined in the concentration range 20-60 mass%. The interference fringes are analyzed to distinguish between the layers of heat conduction and mass diffusion. The temperature and concentration distributions thus determined experimentally are compared with numerical solutions obtained by the equations for unsteady heat conduction and mass diffusion taking into consideration the effect of heat by dilution, to give reasonable values of mass diffusivity hitherto remaining unknown. Especially in the range of 40-60 mass%, the mass diffusivity decreases extremely with the increase of mass concentration of LiBr and it falls down to 0.7-0.8×10^-9 m²/s in case of 60 mass% solution.

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This study was undertaken to meet the demand of the tuna industry for the definite criterion of T. T. T. of on-board frozen tuna during on-land frozen storage, from the veiw point of energy saving.
Yellowfin (YF), southern bluefin (SB) and bigeye (BE) tuna which had been frozen-stored on board in semi-dressed form, excluding gills and viscera, commercially were further stored experimentally at -40, -30 and -20°C on the premise that a target of commercial storage period was 6 months. Decision on tolerance limits was given by degree of discoloration of the meat (met-myoglobin ratio).
Results are as follows :
T. T. T. of YF and SB was estimated to be 6 months^∗ and that of BE to be 17 months^∗ at -40°C, and that of the three tunas examined to be 6 months^∗ at -30°C. T. T. T. of YF and SB was estimated to be 1.5 and 4-5 months (2-3 and 5 months in the case of meat block), respectively, and that of BE to be one month at -20°C. (Asterisks indicate merely the length of the experimental storage, actual T. T. T therefore, must be longer).

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