JP2006308241A - Heat pump type air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump type air conditioner capable of performing stable continuous operation by preventing the temperature drop of a heat exchanger in an exhaust passage, and eliminating the necessity of defrosting operation during heating operation. <P>SOLUTION: The heat pump type air conditioner is provided with a total enthalpy heat exchanger 4 between an air supply passage 2 and an exhaust passage 3 and constituted to switchingly perform air-conditioning operation and heating operation to an air-conditioned room by allowing a refrigerant from a compressor 12 to flow through a first heat exchanger 7 provided downstream of the total enthalpy heat exchanger 4 in the air supply passage 2, and a second heat exchanger 10 provided downstream of the total enthalpy heat exchanger 4 in the exhaust passage 3 in the order of the first heat exchanger and the second heat exchanger or reversely. The heat pump type air conditioner is further provided with a by-pass air passage 15 by-passing the total enthalpy heat exchanger 4 in the exhaust passage 2, and an opening control damper mechanism 16 in the by-pass air passage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat pump type air conditioner that introduces outside air and exchanges heat with the return air from the air-conditioned room by a total heat exchanger, and can be performed by switching between cooling and heating by operating a refrigerant circuit. The present invention relates to an air conditioner capable of preventing frost formation on a heat exchanger acting as an evaporator during heating operation.

  In the outside air processing type air conditioner that sends introduced outside air to the air-conditioned room after air conditioning and discharges the return air from the air-conditioned room to the outside, air supply air flow that sends the outside air to the air-conditioned room after air conditioning A total heat exchanger that straddles these two flow paths is provided between the passage and the exhaust flow path that exhausts the return air from the air-conditioned room to the outside, and heat exchange between the outside air and the return air by this total heat exchanger In the prior art, the residual heat energy in the return air is recovered by the above, and one of the heat exchangers of the heat pump circuit is disposed in each of the two flow paths to further recover waste heat, thereby saving energy. (For example, refer to Patent Document 1).

  By the way, in the apparatus as described above, the heat exchanger in the exhaust passage acts as an evaporator of the refrigerant circuit during the heating operation in winter, but when the outside air temperature decreases, the temperature of the air outlet in the evaporator becomes 5 ° C. May decrease to:

In such a case, there is a risk of frost formation on the evaporator, and in the case of frost formation, a defrost operation for supplying high-temperature refrigerant gas from the compressor to the evaporator must be performed. Heating air cannot be supplied to the air-conditioned room, and thus the heating operation is interrupted.
JP-A-7-310964 (pages 1 to 4, FIGS. 1 to 4)

  The present invention provides a heat pump type air conditioner that prevents a temperature drop of a heat exchanger in an exhaust passage, eliminates the need for a defrosting operation during heating operation, and can perform a stable continuous operation. It is aimed.

  In order to solve the above problems, a heat pump air conditioner according to the present invention includes an air supply passage having an outside air inlet and an air supply port to an air-conditioned room, an air return port from the air-conditioned room, and the outside. A first heat exchange provided between the supply air flow path and the exhaust flow path and provided downstream of the total heat exchanger in the supply air flow path. And the second heat exchanger provided on the downstream side of the total heat exchanger in the exhaust flow path, the refrigerant from the compressor is used in the order of the first heat exchanger and the second heat exchanger or vice versa. In the heat pump type air conditioner configured to switch between cooling operation and heating operation for the air-conditioned room, a bypass air flow path that bypasses the total heat exchanger is provided in the exhaust flow path. A structure in which a damper mechanism for opening control is provided in the bypass air flow path. There is as of.

  Further, the damper mechanism is configured to be controlled such that when the outside air temperature falls below a predetermined value during the heating operation, the opening degree increases as the temperature falls.

And instead of the outside air temperature, the temperature of at least one of the air inlet or the outlet of the second heat exchanger, the evaporation pressure of the second heat exchanger, the outlet refrigerant temperature of the second heat exchanger, In some cases, the damper mechanism may be controlled so that the opening degree of the damper mechanism increases as various physical quantities such as the front wind speed of the second heat exchanger decrease.

  According to the present invention, since the bypass air flow path that bypasses the total heat exchanger is provided in the exhaust flow path, the second heat exchanger in the exhaust flow path passes through the bypass air flow path, and the total heat exchanger Bypass air that does not pass through can be supplied.

  During the heating operation in winter, the temperature of the bypass air is higher than that of the air that has passed through the total heat exchanger, so the air that has passed through the total heat exchanger and the bypass air are mixed and supplied to the second heat exchanger. As a result, the temperature of the air supplied to the second heat exchanger can be raised, and therefore frost formation on the heat exchanger due to the temperature drop of the second heat exchanger is prevented, and the defrosting operation is performed. This eliminates the need for stable continuous operation.

In addition, a damper mechanism is provided in the bypass air flow path, and the opening degree is adjusted according to the outside air temperature or the like, so that the bypass air amount is controlled as necessary and sufficient. Waste heat recovery can be expected.

An embodiment of a heat pump type air conditioner according to the present invention will be described in detail with reference to the accompanying drawings.
In the casing 1, there are an air supply passage 2 extending from an outside air inlet 2a to an air supply port 2b to an air-conditioned room (not shown), and a return air port 3a for introducing return air from the air-conditioned room to the outside. An exhaust passage 3 reaching the exhaust port 3b is provided, and a total heat exchanger 4 straddling the two passages is provided between the air supply passage 2 and the exhaust passage 3.

In the air supply flow path 2, a filter 5, the total heat exchanger 4, the humidifier 6, the first heat exchanger 7, and the blower 8 are provided in this order from the outside air outlet 2 a toward the air inlet 2 b. The exhaust passage 3 is provided with a filter 9, the total heat exchanger 4, the second heat exchanger 10, and the blower 11 in order from the return air port 3 </ b> A toward the exhaust port 3 </ b> B.
The filter 5 in the air supply channel 2 has a two-stage configuration of, for example, a pre-filter 5a and a medium performance filter 5b.

  Further, a compressor 12 of a refrigerant circuit is provided between the filter 9 and the total heat exchanger 4 in the exhaust passage 3, and the refrigerant from the compressor 12 is exchanged with the first heat exchanger 7. The second heat exchanger 10 is switched and supplied by the four-way valve 13 in this order or vice versa, and is returned to the compressor via the accumulator 14, and the cooling operation is performed by switching the four-way valve. And heating operation are switched.

Specifically, during cooling operation, as indicated by solid arrows in FIG. 1, the refrigerant from the compressor 12 is sent to the second heat exchanger 10 via the four-way valve 13 and flows through the exhaust passage 3. The air is condensed by heat exchange with the air to be sent and sent to the first heat exchanger 7. The air evaporated in the first heat exchanger and flowing through the air supply passage 2 is cooled and sent to the accumulator 14. The gas and liquid are separated by the accumulator and returned to the compressor 12.
The air cooled by the first heat exchanger 7 is sent to the air-conditioned room.

Further, during the heating operation, as indicated by broken line arrows in FIG. 1, the refrigerant from the compressor 12 is sent to the first heat exchanger 7 through the four-way valve 13, and the air flowing through the air supply passage 2 The heat is condensed by the heat exchange to heat the air in the air supply flow path, and the condensed refrigerant is sent to the second heat exchanger 10 to be evaporated and take the heat of the air flowing through the exhaust flow path 3, Thereafter, the gas and liquid are separated by an accumulator and returned to the compressor 12.
In addition, the air heated with the 1st heat exchanger 7 is sent to an air-conditioned room.

  Therefore, in the apparatus of the present invention, a bypass air flow path 15 that bypasses the total heat exchanger 4 in the exhaust flow path 3 is provided, and a damper mechanism 16 is provided in the bypass air flow path, By controlling the opening degree of the damper mechanism, a part of the air flowing in the exhaust passage 3 can be sent to the second heat exchanger 10 without flowing through the total heat exchanger. ing.

The damper mechanism 16 is configured such that the opening degree is adjusted by a signal from a temperature sensor (not shown) provided inside the outside air inlet 2a and a temperature controller (not shown), for example, and heating operation in winter When the outside air temperature falls below a preset temperature at the time, the opening degree is configured to increase according to the degree of the fall.
In FIG. 1, reference numerals 17 and 18 denote first heat exchangers and expansion valves for the second heat exchanger, and 19 and 20 denote check valves for the first heat exchanger and the second heat exchanger, respectively. ing.

Next, the operation of the apparatus having the above-described configuration will be described.
During the cooling operation in summer, the air from the outside air inlet 2a flows through the total heat exchanger 4 through the filter 5 and exchanges heat with the air in the exhaust passage 3, and is not operated in principle during the cooling operation. It passes through the humidifier 6 and is sent to the first heat exchanger 7.

Since the first heat exchanger 7 acts as an evaporator during the cooling operation, the air in the air supply passage 2 is cooled to a required temperature in the first heat exchanger, and the air supply port 2b is driven by driving the blower 8. And is sent to the air-conditioned room by air supply means such as a duct (not shown) connected to the air supply port.

  The return air returned from the air-conditioned room by the air supply means such as a duct flows into the exhaust passage 3 from the return air port 3a, passes through the filter 9, and is sent to the total heat exchanger 4 to be supplied. Heat is exchanged with the air in the air flow path 2, the heat of condensation of the refrigerant is taken away by the second heat exchanger 10, and the air is discharged from the exhaust port 3 b to the outside by driving the blower 11.

  In the cooling operation, all the air flowing through the exhaust passage 3 passes through the total heat exchanger 4 in principle, and the damper mechanism 16 of the bypass air passage 15 is fully closed.

Further, during the heating operation in winter, the air from the outside air inlet 2a flows through the total heat exchanger 4 through the filter 5 and exchanges heat with the air in the exhaust passage 3, and then the humidity is increased by the humidifier 6. It is adjusted and sent to the first heat exchanger 7.

Since the first heat exchanger 7 acts as a condenser during the heating operation, the air in the air supply passage 2 is heated to a required temperature in the first heat exchanger, and the air supply port is driven by driving the blower 8. 2b and sent to the air-conditioned room by air supply means such as a duct (not shown) connected to the air supply port.

  The return air returned from the air-conditioned room by the air supply means such as a duct flows into the exhaust passage 3 from the return air port 3a, passes through the filter 9, and is sent to the total heat exchanger 4 to be supplied. Heat is exchanged with the air in the air flow path 2, the refrigerant evaporates and cools in the second heat exchanger 10, and is discharged to the outside through the exhaust port 3 b by driving the blower 11.

  During the heating operation described above, the bypass air flow path 15 is closed by the damper mechanism 16 in principle. However, when the outside air temperature decreases, the opening degree of the damper mechanism is controlled to be large, and the total heat exchange is performed. The proportion of air that does not flow through the vessel increases.

  As described above, the amount of air that does not flow through the total heat exchanger becomes large, which means that the amount of relatively high-temperature air that is not cooled by the cold heat of the outside air that flows through the supply air passage in the total heat exchanger increases. Thus, the temperature of the air sent to the second heat exchanger 10 rises.

  Therefore, a decrease in temperature in the second heat exchanger 10 is prevented, and this temperature can be set to a temperature higher than 5 ° C., that is, a temperature at which there is no fear of frost formation on the second heat exchanger. There is no need to perform a defrosting operation for defrosting the exchanger.

  That is, since the device of the present invention does not require a defrosting operation, not only can a stable continuous heating operation be performed, but also a refrigerant circuit for the defrosting operation is not required, and energy loss associated with the defrosting operation is eliminated. There is also an advantage that it can be lost.

  FIG. 2 is a moist air diagram showing the air state in the apparatus of the present invention. The outside air is a dry bulb temperature of 0.6 ° C. and a humidity of 33%, and the return air is a dry bulb temperature of 22 ° C. and a humidity of 40%. The results of the simulation with the bypass air amount set to 35% are shown as a1 in the air state at the air inlet of the second heat exchanger 10 and a2 in the air state at the outlet.

  For comparison, the air condition at the air inlet of the second heat exchanger 10 is b1 and the air condition at the outlet is b2 when the conditions of the outside air and the return air are the same as above, and the bypass air amount is zero. As shown.

  As is apparent from the air diagram of FIG. 2, when the bypass air amount is set to 0, the air temperature at the outlet of the second heat exchanger is about 0 ° C., and frost formation is a concern. It can be seen that the air temperature at the outlet of the second heat exchanger is 7.3 ° C. in terms of dry bulb temperature and there is no risk of frost formation in the present invention with 35%.

  In the embodiment described above, the opening degree control of the damper mechanism that adjusts the amount of bypass air is performed based on the temperature inside the outside air inlet 2a, but instead of the control based on the outside air temperature itself, the outside air temperature is changed. In some cases, control is performed based on various physical quantities that fluctuate along with, for example, the air temperature at the air inlet or outlet of the second heat exchanger, the evaporating pressure of the refrigerant in the second heat exchanger, or the refrigerant temperature at the refrigerant outlet In some cases, the control is based on a decrease, and in some cases, the control is based on a decrease in front wind speed in the second heat exchanger, that is, an increase in ventilation resistance due to the start of frost formation on the second heat exchanger.

The system diagram which shows the structure of the Example of the apparatus which concerns on this invention. The wet air diagram for demonstrating the effect | action of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 2 Supply air flow path 3 Exhaust flow path 4 Total heat exchanger 5 Filter 6 Humidifier 7 1st heat exchanger 8 Blower 9 Filter 10 2nd heat exchanger 11 Blower 12 Compressor 13 Four-way valve 14 Accumulator 15 Bypass air flow Path 16 Damper mechanism 17, 18 Expansion valve 19, 20 Check valve

Claims (7)

  These air supply passages are provided between an air supply passage having an outside air introduction port and an air supply port to the air-conditioned room, and an exhaust passage having a return air port from the air-conditioned room and an exhaust port to the outside. A first heat exchanger provided on the downstream side of the total heat exchanger in the supply air flow path; and a first heat exchanger provided on the downstream side of the total heat exchanger in the exhaust flow path. The refrigerant from the compressor is circulated through the two heat exchangers in the order of the first heat exchanger and the second heat exchanger or vice versa so as to switch between the cooling operation and the heating operation for the air-conditioned room. In the heat pump type air conditioner configured, a heat pump type in which a bypass air passage for bypassing the total heat exchanger is provided in the exhaust passage, and a damper mechanism for opening degree control is provided in the bypass air passage. Air conditioner.   2. The damper mechanism according to claim 1, wherein when the outside air temperature is lower than a predetermined value during the heating operation, the damper mechanism is controlled so that the opening degree increases as the temperature decreases. Heat pump type air conditioner.   The heat pump air conditioner according to claim 1, wherein the damper mechanism has an opening controlled according to a physical quantity that varies with a change in outside air temperature during heating operation.   The physical quantity is a temperature of at least one of the air inlet and the outlet of the second heat exchanger, and when the temperature falls below a predetermined value, the damper mechanism opens as the temperature falls. The heat pump type air conditioner according to claim 3, wherein the heat pump type air conditioner is controlled so as to increase the degree.   The physical quantity is an evaporation pressure of the second heat exchanger, and when the pressure falls below a predetermined value, the opening of the damper mechanism is controlled to increase as the pressure falls. The heat pump type air conditioner according to claim 3.   The physical quantity is the outlet refrigerant temperature of the second heat exchanger, and when the temperature falls below a predetermined value, the opening of the damper mechanism is controlled to increase as the temperature falls. The heat pump type air conditioner according to claim 3. The physical quantity is the front wind speed of the second heat exchanger, and when the wind speed falls below a predetermined value, the opening of the damper mechanism is controlled to increase as the wind speed falls. The heat pump type air conditioner according to claim 3.

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