JP2008138924A - Steam generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further improve heat efficiency in comparison with a conventional steam generator and energy saving effect and to contribute on environment protection. <P>SOLUTION: This steam generator 100 has a natural refrigerant heat pump 10, a decompression boiling tank 20 receiving hot water from the natural refrigerant heat pump 10, and a compressor 30 for compressing the steam from the decompression boiling tank 20. The steam generator 100 preferably has an accumulator 40 for storing high-pressure steam compressed by the compressor 30, and further preferably has a hot water tank 15 receiving the hot water from the natural refrigerant heat pump 10 and supplying the hot water to the natural refrigerant heat pump 10. Further a control device 50 is disposed to operate the compressor 30 on the basis of pressure and temperature information in the accumulator 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a steam generator using a heat pump and a steam compressor.

  In the field of cold and heat, heat pumps are used as a means to improve thermal efficiency and save energy. For example, natural refrigerant heat pump electric water heaters worked by industry such as an electric company called hot water and water heater manufacturers. Is attracting attention because of its high thermal efficiency. Attempts have been made to improve heat efficiency and save energy by using such a heat pump in a steam generator.

  For example, Patent Document 1 is a steam supply system, which includes a boiler having a combustion section and a heat pump, and uses the heat pump to heat a medium to be heated in a relatively low temperature region. A steam supply system using the boiler has been proposed. And it is disclosed that various well-known heat media, such as a fluorocarbon medium, ammonia, and water, can be applied as a heat medium of a heat pump.

  Patent Document 2 consists of an absorption heat pump and a boiler. An absorption heat pump device that supplies hot water by operating either the absorption heat pump or the boiler according to the level of the outside air temperature, and first making hot water with the absorption heat pump, Next, an absorption heat pump device has been proposed that can be heated by a reheating boiler and can supply hot water at a higher temperature.

  Further, Patent Document 3 discloses an absorption heat pump that is provided with an absorption heat pump that generates steam based on 90 ° C hot water and a steam boiler, and that operates the absorption heat pump preferentially and efficiently supplies the steam to the steam turbine. Proposed.

JP 2006-308164 A JP 2006-125698 A JP 2006-207882 JP

  However, such a conventional steam generator employs a mechanism that generates steam by fuel combustion energy or electric energy, and its thermomechanical conversion efficiency should be 100% (coefficient of performance COP = 1) or more. There is a limit to improving the efficiency of the steam generator. For this reason, such a conventional steam generator has a problem that it is difficult to further increase the thermal efficiency and achieve an energy saving effect.

  In view of such problems, the present invention has an object to provide a steam generator that can further increase thermal efficiency, achieve an energy saving effect, and can contribute to environmental conservation.

  The steam generator according to the present invention includes a natural refrigerant heat pump, a vacuum boiling tank that receives hot water from the natural refrigerant heat pump, and a compressor that compresses water vapor from the vacuum boiling tank.

  In the above invention, it is preferable to provide a pressure accumulating tank for storing high-pressure steam compressed by the compressor, and it is preferable to provide a hot water tank for receiving hot water from the natural refrigerant heat pump and supplying hot water to the natural refrigerant heat pump. . Moreover, it is good to provide the control apparatus which operates the said compressor based on the pressure and temperature information in the said pressure accumulation tank. Further, the compressors can be provided in multiple stages in series. In this case, higher pressure steam can be obtained.

  According to the steam generator according to the present invention, the thermal efficiency is further increased than the conventional steam generator, the energy saving effect is achieved, and as a result, the generation amount of carbon dioxide gas, chlorofluorocarbon gas, etc., which is a problem due to global warming, is suppressed. Can contribute to environmental conservation.

  Embodiments of a steam generator according to the present invention will be described below with reference to the drawings. FIG. 1 shows a layout diagram of a steam generator according to the present invention. As shown in FIG. 1, the steam generator 100 includes a natural refrigerant heat pump 10, a vacuum boiling tank 20 that receives hot water from the natural refrigerant heat pump 10, and a compressor 30 that compresses water vapor from the vacuum boiling tank 20. Have. The steam generator 100 receives hot water from the accumulator 40 that stores high-pressure steam compressed by the compressor 30 and the natural refrigerant heat pump 10, which will be described below, and supplies hot water to the natural refrigerant heat pump 10. A control device 50 that operates the compressor 30 based on the pressure and temperature information in the hot water tank 15 and the pressure accumulating tank 40 is preferably provided.

  The natural refrigerant heat pump 10 may be a heat pump using a natural refrigerant such as environmentally friendly water or carbon dioxide. A natural refrigerant heat pump 10 using carbon dioxide as a refrigerant, which is used for so-called eco-cute, can be used.

  The inside of the vacuum boiling tank 20 can be depressurized by a vacuum pump or a suction vacuum of the compressor 30, and the hot water received from the natural refrigerant heat pump 10 can be boiled. The water vapor generated in the vacuum boiling tank 20 is supplied to the compressor 30. A predetermined temperature can be maintained by supplying warm water in the vacuum boiling tank 20 to the natural refrigerant heat pump 10 side.

  The compressor 30 can compress the steam generated in the vacuum boiling tank 20 and change it into high-pressure steam having a predetermined temperature and pressure. A turbo-type, screw-type or reciprocating-type compressor can be used for the compression of the water vapor.

  The steam generator 100 is preferably provided with a pressure accumulating tank 40 that temporarily stores high-pressure steam generated by the compressor 30. And it is good to provide the control apparatus 50 which operates the compressor 30 based on the pressure in the pressure accumulation tank 40, and temperature information. As a result, even when there is a load change, high-pressure steam having a predetermined characteristic can be supplied to the load side.

  Further, the steam generator 100 is preferably provided with a hot water tank 15 for receiving hot water from the natural refrigerant heat pump 10 and supplying hot water to the natural refrigerant heat pump 10. Thereby, when the load decreases, the hot water generated by the natural refrigerant heat pump 10 is stored in the hot water tank 15, and when the load increases, the hot water stored in the hot water tank 15 is supplied to the vacuum boiling tank 20. Thus, it is possible to supply high-pressure steam with high energy efficiency. The warm water tank 15 can be provided with a heater using midnight power. Thereby, even if there are fluctuations in the outside air temperature, hot water having a constant temperature can be supplied, and energy efficiency can be improved.

  The control device 50 can control the compressor 30 based on the pressure and temperature information in the pressure accumulating tank 30 as described above, and further, the water vapor pressure and temperature information in the vacuum boiling tank 20, natural refrigerant It is preferable that these devices can be controlled based on temperature information on the heat pump 10 and the hot water tank 15, temperature information on the outside air temperature, and the like. As a result, the steam generator 100 can be efficiently operated.

The steam generator 100 has been described above. As described above, the steam generator 100 does not employ a mechanism for generating steam by fuel combustion energy or electric energy, and therefore can generate high-pressure steam with high energy efficiency. With this steam generator 100, for the source water at 20 ° C., energy of 1 kW is added to the natural refrigerant heat pump 10 to generate 90 ° C. hot water, and the hot water is converted into water vapor in the vacuum boiling tank 20, and then the compressor 30 Table 1 shows the energy calculation when 0.294 MPa (3.0 kg / cm ² abs) in absolute pressure and 4.7 kg / h of saturated water vapor at 133 ° C. are generated. In actual use, for example, if a capacity of 100 kg / h is required, the natural refrigerant heat pump 10 may be supplied with 21.1 times the energy of 21.1 kW.

  The results of Table 1 are illustrated as shown in FIG. The horizontal axis indicates the enthalpy in each of the above steps of the steam generator 100, and the vertical axis indicates the temperature at which the source water changes in each step. The area surrounded by the diagram in the figure indicates the energy supplied to the steam generator 100. 2B shows a comparative example, in which 1 kW of energy is added to the natural refrigerant heat pump 10 to generate 90 ° C. hot water, and the hot water is heated by an electric boiler with efficiency (COP = 0.98). A case similar to that shown in FIG. 2 (a) is shown based on energy calculation in the case of generating 4.7 kg / h of saturated steam at a pressure of 0.294 MPa and 133 ° C.

  As shown in FIG. 2, the average coefficient of performance COP in the case of the comparative example is only 1.29 (FIG. 2B), whereas the average coefficient of performance COP in the case of the present invention is about 3.73 (FIG. 2). (A)), it can be seen that the energy efficiency is about three times.

1 is a layout diagram of a steam generator according to the present invention. It is explanatory drawing regarding the thermal efficiency of the steam generator of FIG.

Explanation of symbols

10 Natural refrigerant heat pump
15 Hot water tank
20 Vacuum boiling tank
30 Compressor
40 pressure storage tank
50 Control unit
100 steam generator

Claims (4)

  A steam generator comprising: a natural refrigerant heat pump; a vacuum boiling tank that receives hot water from the natural refrigerant heat pump; and a compressor that compresses water vapor from the vacuum boiling tank.   The steam generator according to claim 1, further comprising a pressure accumulating tank for storing high-pressure steam compressed by the compressor.   The steam generator according to claim 1 or 2, further comprising a hot water tank that receives hot water from the natural refrigerant heat pump and supplies hot water to the natural refrigerant heat pump.   The steam generator according to claim 2 or 3, further comprising a control device for operating the compressor based on pressure and temperature information in the pressure accumulating tank.

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