JP2007322051A - Heat pump type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump type water heater capable of accurately and inexpensively detecting a refrigerant condensation temperature in a plate-type water heat exchanger used as a water heat exchanger, and protecting a heat pump cycle. <P>SOLUTION: This heat pump type water heater comprises the heat pump cycle, the plate-type water heat exchanger is used as the water heat exchanger of the heat pump cycle, bypass piping comprising a throttle device is disposed in parallel with the plate-type water heat exchanger, and a temperature sensor is mounted on the bypass piping, so that a temperature of a refrigerant flowing in the bypass piping is detected, and a temperature of the refrigerant flowing in the plate-type water heat exchanger is estimated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat pump type hot water supply apparatus, and more particularly to a heat pump type hot water supply apparatus that can detect abnormality of a heat pump cycle and a compressor.

  In general, in heat pump hot water supply devices, the load fluctuation due to changes in the water temperature sent to the water heat exchanger is large, so it has a large effect on the refrigeration cycle, and the refrigerant temperature in the water heat exchanger is constantly detected to control the compressor speed. Thus, it is necessary to control the capacity of the refrigeration cycle.

  On the other hand, in a heat pump type hot water supply apparatus, a plate type water heat exchanger is often used as a water heat exchanger for exchanging heat between a medium such as water or antifreeze and a refrigerant.

  This type of plate-type water heat exchanger is a water system in which a plurality of parallel water flow paths are provided between an end plate provided with a refrigerant inflow pipe, a water supply pipe and a hot water supply pipe, and an end plate provided with a refrigerant outflow pipe. The side heat transfer plate and the refrigerant side heat transfer plate provided with a plurality of refrigerant flow paths arranged in parallel are assembled in an airtight manner, and further, the refrigerant and water are arranged to face each other.

  For the above reasons, it is necessary to know the exact refrigerant temperature (condensation temperature) of the water heat exchanger, but because the plate type water heat exchanger has the above structure, a condensation temperature sensor is installed inside the plate type water heat exchanger. In addition, it is difficult to measure the temperature at the center thereof, and further, if two refrigerant temperature sensors are provided in the refrigerant inlet pipe and outlet pipe of the plate type water heat exchanger, two temperature sensors are required. It becomes expensive, and calculating the refrigerant temperature from the temperatures detected by the two temperature sensors requires extra means. Furthermore, it is not accurate or reliable to detect the refrigerant at the inlet / outlet of the plate type water heat exchanger or the temperature of the water inlet / outlet to estimate the inside of the plate type water heat exchanger.

  Further, a pressure sensor is provided in the heat pump cycle for protecting the compressor and the like, but the pressure sensor is more expensive than the temperature sensor.

In addition, the heat pump type hot water supply apparatus which provided the temperature sensor in the exit of a compressor and the exit of a water heat exchanger is disclosed (patent document 1).
JP 2005-315558 A

  The present invention has been made in consideration of the above-described circumstances, and a heat pump type hot water supply apparatus that can accurately and inexpensively detect the refrigerant condensation temperature in a plate type water heat exchanger used as a water heat exchanger and protect the heat pump cycle. The purpose is to provide.

  In order to achieve the above-described object, a heat pump type hot water supply apparatus according to the present invention includes a heat pump type hot water supply provided with a heat pump cycle in which a compressor, a water heat exchanger, a pressure reduction mechanism, and a heat source side heat exchanger are sequentially connected by piping. In the apparatus, a plate type water heat exchanger is used as the water heat exchanger, a bypass pipe having a throttle mechanism is provided in parallel with the plate type water heat exchanger, and a temperature sensor is attached to the bypass pipe. A means for detecting the temperature of the refrigerant flowing in the pipe and estimating the temperature of the refrigerant flowing in the plate-type water heat exchanger is provided.

  According to the heat pump type hot water supply apparatus according to the present invention, there is provided a heat pump type hot water supply apparatus that can accurately and inexpensively detect the refrigerant condensing temperature in the plate type water heat exchanger used as the water heat exchanger and protect the heat pump cycle. Can do.

  A heat pump type hot water supply apparatus according to a first embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a conceptual diagram of a heat pump type hot water supply apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, the heat pump hot water supply device 1 of the first embodiment includes a heat pump cycle 2. This heat pump cycle 2 is configured by sequentially connecting a compressor 3, a four-way valve 4, a plate type water heat exchanger 5, a pressure reducing mechanism 6, and an air heat exchanger 7 which is a heat source side heat exchanger, and a refrigerant circuit is formed. It is formed.

  In addition, a bypass pipe 8 provided with a capillary tube 8 a serving as a throttling mechanism is provided in parallel with the plate type water heat exchanger 5.

  Further, a hot water supply circuit 14 including a water supply pipe 9, a hot water supply pipe 10, a water supply pump 11, a pipe joint 12, and a hot water storage tank 13 is communicated with the plate type water heat exchanger 5.

  As shown in FIGS. 2 and 3, the plate-type water heat exchanger 5 used as a water heat exchanger includes an end plate 16 to which a refrigerant inflow pipe 15i, a water supply pipe 9, and a hot water supply pipe 10 are attached, and a refrigerant outflow pipe 15o. A water side heat transfer plate 18 provided with a plurality of parallel water flow paths 18a and a refrigerant side heat transfer plate 19 provided with a plurality of parallel refrigerant flow paths 19a are hermetically assembled between the end plates 17 attached with Furthermore, the refrigerant and water (or a medium such as antifreeze) are arranged so as to face each other.

  In addition, the plate type water heat exchanger may be used by stacking one heat exchange unit shown in FIG.

  The plate type water heat exchanger 5 having such a structure is connected to the refrigerant pipe and the hot water pipe as follows. For example, the refrigerant inflow pipe 15i is connected to the discharge side of the compressor 3 through the four-way valve 4, the refrigerant outflow pipe 15o is connected to the air heat exchanger 7 on the heat source side through the pressure reducing mechanism 6, and the water supply pipe 9 is connected to the water supply pump 11, the hot water supply pipe 10 is connected to the hot water supply side of the hot water storage tank 13 by piping.

As shown in FIG.1 and FIG.4, the heat pump type hot water supply apparatus 1 is provided with a control device 20 for controlling the entire device, and this control device 20 is connected to an inverter type rotation via a necessary interface (not shown). the number variable of the compressor 3, an air heat exchanger fan 21, the four-way valve 4, the water supply pump 11, the suction refrigerant temperature sensor S ₁ provided on the suction side pipe of the compressor _3, the discharge refrigerant temperature sensor S provided on the discharge side pipe _{2. Between} the suction side temperature sensor S ₃ provided in the refrigerant inlet side pipe of the air heat exchanger 7, the air heat exchanger temperature sensor S ₄ provided in the air heat exchanger 7, and the capillary tube 8 a interposed in the bypass pipe 8 The refrigerant condensing temperature sensor S ₅ attached to the intermediate part of the bypass pipe, the water supply temperature sensor S ₆ provided in the water supply pipe 9, and the hot water supply temperature sensor S ₇ provided in the hot water supply pipe 10 are connected, Controller 20 CPU 20a, provided with a memory 20b, based on the content of the operation instruction information indicated by the temperature information or the user from the temperature _S 1 to S _7, the method of operating the compressor 3, an air heat exchanger fan 21 The function of controlling the operation of the water supply pump 11 and the operation of the four-way valve 4 is provided.

  Next, operation | movement of this heat pump type hot-water supply apparatus is demonstrated.

  In the refrigeration cycle of the heat pump unit 1 shown in FIG. 1, the high-temperature and high-pressure gas refrigerant discharged from the compressor 3 is condensed while dissipating heat to the hot water supply circuit 14 side in the plate-type water heat exchanger 5, and is dissipated from the refrigerant. The water in the hot water supply circuit 14 is heated by the generated heat.

  The condensed refrigerant flowing out of the plate-type water heat exchanger 5 is decompressed by the decompression mechanism 6, flows into the air heat exchanger 7 on the heat source side, exchanges heat with the outside air, absorbs heat from the outside air, and is evaporated and gasified. The Further, the low-pressure gas refrigerant flowing out from the heat source side air heat exchanger 7 is sucked into the compressor 3.

  On the hot water supply circuit 14 side, the heat radiated from the refrigerant in the plate type water heat exchanger 5 is guided from the lower part of the hot water storage tank 13 by the water supply pump 11 provided on the water supply side of the plate type water heat exchanger 5. Thus, the water is fed to the hot water supply circuit 14 side of the plate-type water heat exchanger 5. Here, the heated and generated hot water flows from the upper part of the hot water storage tank 13 and is stored in the hot water storage tank 13.

  During the operation of the heat pump type hot water supply apparatus, hot water is supplied from the hot water storage tank 13 according to a user's request for hot water supply, and the load of the heat pump cycle 2 varies.

  In order to cope with this variation, the capacity of the refrigeration cycle is controlled appropriately by controlling the capacity of the refrigeration cycle, for example, the rotational speed of the compressor.

  This control is performed as follows.

  An operational test of a heat pump type hot water supply device of the same type as this heat pump type hot water supply device is conducted in advance, and the refrigerant temperature (actual temperature) flowing through the plate type water heat exchanger and the refrigerant temperature of the capillary tube detected by the refrigerant condensation temperature sensor (measurement) Temperature) is obtained and stored in the memory 20b.

By detecting the refrigerant temperature flowing at all times the plate type water heat exchanger 5 (the measurement temperature) by the refrigerant condensing temperature sensor S _5, the control unit 20, calculates the temperature of the refrigerant flowing through the plate-type water heat exchanger 5. Thus, the condensation temperature of the plate-type water heat exchanger can be estimated by measuring the intermediate temperature of the capillary tube.

  Based on the calculated refrigerant condensing temperature, the operation capacity of the compressor 3 is controlled. In this operation capacity control, a preferable operation frequency of the compressor is determined from the refrigerant condensing temperature, the rotation of the compressor 3 is controlled, and the load is appropriately handled. Moreover, when the abnormal value of refrigerant | coolant condensing temperature is detected, the operation | movement of a heat pump type hot-water supply apparatus is stopped as an abnormality having arisen in the heat pump cycle or the compressor.

  In the calculation method of the refrigerant condensing temperature using the refrigerant temperature (measured temperature) of the bypass pipe as in the first embodiment, as shown in FIG. 5, the bypass pipe is used at a compressor frequency outside a predetermined range. Since the amount of flowing refrigerant fluctuates and a slight error occurs between the measured temperature and actual temperature, the refrigerant temperature in the bypass pipe used for the calculation of the condensation temperature is corrected in advance by testing, and the plate-type water is used using this corrected temperature. It is preferable to estimate the condensation temperature of the heat exchanger. Thereby, the temperature of the refrigerant flowing through the plate type water heat exchanger can be accurately grasped, and the heat pump cycle can be reliably protected.

  Further, by providing a temperature sensor in the bypass pipe, it becomes cheaper than the pressure sensor.

  According to the heat pump type hot water supply apparatus of the first embodiment, the refrigerant condensing temperature in the plate type water heat exchanger used as the water heat exchanger can be detected accurately and inexpensively, and the heat pump cycle can be protected.

  Next, a heat pump type hot water supply apparatus according to a second embodiment of the present invention will be described.

  In the second embodiment, an electronic expansion valve is provided instead of the capillary tube in the bypass pipe of the first embodiment.

For example, as shown in FIG. 6, the heat pump hot water supply device 31 of the second embodiment is provided with a bypass pipe 8 provided with two electronic expansion valves 32, and two electrons interposed in the bypass pipe 8. the bypass pipe intermediate portion between the expansion valve 32 provided refrigerant condensing temperature sensor S _5. Thereby, the effect similar to Embodiment 1 is acquired. Further, by changing the opening degree of the electronic expansion valve 32 according to the frequency of the compressor 3, as shown in FIG. 7, there is no error between the measured temperature and the actual temperature within the entire range of the compressor frequency. Without correcting the measurement temperature, the measurement temperature of the bypass pipe temperature sensor can be used as it is, and the range in which the condensation temperature can be estimated is expanded.

  One electronic expansion valve may be provided either before or after the temperature sensor of the bypass pipe, and the other may be constituted by a capillary tube.

  Since the other configuration is not different from the heat pump type hot water supply apparatus shown in FIG.

The conceptual diagram of the heat pump type hot-water supply apparatus which concerns on 1st Embodiment of this invention. The disassembled perspective view of the plate-type water heat exchanger used for the heat pump type hot-water supply apparatus which concerns on 1st Embodiment of this invention. The longitudinal cross-sectional view of the plate-type water heat exchanger used for the heat pump type hot-water supply apparatus which concerns on 1st Embodiment of this invention. The control circuit diagram used for the heat pump type hot-water supply apparatus which concerns on 1st Embodiment of this invention. Explanatory drawing of the relationship between the compressor frequency and condensation temperature of the heat pump type hot water supply apparatus which concerns on 1st Embodiment of this invention. The conceptual diagram of the heat pump type hot water supply apparatus which concerns on 2nd Embodiment of this invention. Explanatory drawing which shows the relationship between the opening degree change of the electronic expansion valve of the heat pump type hot water supply apparatus which concerns on 2nd Embodiment of this invention, and a condensation temperature.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat pump type hot water supply apparatus, 2 ... Heat pump cycle, 3 ... Compressor, 5 ... Plate type water heat exchanger, 6 ... Decompression mechanism, 7 ... Air heat exchanger on the heat source side, 8 ... Bypass piping, 8a ... Capillary tube , 9 ... Water supply pipe, 10 ... Hot water supply pipe, 14 ... Hot water supply circuit, 15i ... Refrigerant inflow pipe, 15o ... Refrigerant outflow pipe, 18 ... Water side heat transfer plate, 18a ... Water flow path, 19 ... Refrigerant side heat transfer plate, 19a ... Refrigerant flow path, 20 ... Control device.

Claims (4)

In a heat pump type hot water supply apparatus equipped with a heat pump cycle configured by sequentially connecting a compressor, a water heat exchanger, a pressure reducing mechanism, and a heat source side heat exchanger, a plate type water heat exchanger is used for the water heat exchanger, In parallel to this plate type water heat exchanger, a bypass pipe equipped with a throttle mechanism is provided, and a temperature sensor is attached to the bypass pipe, and the temperature of the refrigerant flowing in the bypass pipe is detected to detect the inside of the plate type water heat exchanger. A heat pump type hot water supply apparatus comprising means for estimating a temperature of a refrigerant flowing through the water. The compressor is a variable capacity type whose operation frequency is controlled by an inverter, and an estimated value of the refrigerant temperature flowing in the plate type water heat exchanger is set to a temperature actually measured within a predetermined region of the operation frequency, The heat pump type hot water supply apparatus according to claim 1, wherein a refrigerant temperature corrected in accordance with an operation frequency of the compressor is used with respect to an actually measured temperature in a frequency region outside the predetermined region of the operation frequency. The heat pump type hot water supply apparatus according to claim 1, wherein the bypass pipe throttle mechanism is a capillary tube. The heat pump type hot water supply apparatus according to claim 2, wherein the throttle mechanism of the bypass pipe is an electronic expansion valve, and an opening degree of the electronic expansion valve is changed according to an operating frequency of the compressor.

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