JPH042870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an outdoor unit of a heat pump such as a room air conditioner or a water heater that uses air as a heat source.

Conventional structure and its problems Conventionally, in the outdoor unit of an air heat source heat pump, as shown in Fig. 1, an outdoor heat exchanger 1, a blower 2, a compressor (not shown), etc. are installed in a casing 3. outdoor heat exchanger 1 to reduce noise.
This is a so-called intake system installed on the windward side of the blower 2.

In the outdoor heat exchanger 1, heat is exchanged between the outside air flowing in the direction of the arrow 4 between the fins arranged in parallel at regular intervals, and the refrigerant flowing in the heat transfer tubes inserted perpendicularly to the fins.

In such an outdoor unit, when a heating operation is performed at a low outside temperature, the outdoor heat exchanger 1 functions as an evaporator, so water vapor in the outside air adheres to the heat transfer surface as frost and grows into a frost layer. . If the heating operation continues, the space between the fins will be covered with a layer of frost and the air volume will decrease, resulting in a decrease in the amount of heat exchange, and the heating capacity of the heat pump will decrease, making defrosting necessary.

Therefore, conventionally, a temperature sensor for detecting evaporation temperature is attached to the heat transfer tube of the outdoor heat exchanger 1, and when this detected temperature reaches a set value, defrosting operation such as a reverse cycle method is started regardless of the outside air condition. I was doing it.

By the way, the amount of frost accumulated on the outdoor heat exchanger is determined by the outside air temperature and the evaporation temperature.

Therefore, in the conventional method, when the outside temperature is low, the defrosting operation is performed when the set temperature is reached even if there is no frost, or when the set temperature is reached, the amount of frost that has adhered to the heat transfer surface is Since the temperature varies depending on outside temperature conditions, heat pumps have the disadvantage that heating operation is restarted before the frost layer is completely melted within the set time of defrosting operation, which significantly reduces the performance of the heat pump.

OBJECTS OF THE INVENTION An object of the present invention is to realize an outdoor unit of a heat pump that can reliably detect the occurrence of frost formation during heating operation and can also detect a constant amount of frost formation under all outside air conditions.

Structure of the Invention In order to achieve the above object, the outdoor unit of the heat pump of the present invention is an outdoor heat exchanger consisting of fins lined up with cutouts on the front surface on the windward side and heat transfer tubes inserted perpendicularly into the fins. A temperature sensor held between the fins by a support plate of low thermal conductivity such as plastic is provided in the notch of the container, and the outdoor heat exchanger and temperature sensor are subjected to hydrophilic treatment.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 2 to 4. FIG. 2 is a perspective view of the structure of the outdoor heat exchanger and temperature sensor, FIG. 3 is an enlarged detailed view of section A in FIG. 1, and FIG. 4 is an explanatory diagram of the operation.

An outdoor heat exchanger 5, a blower, a compressor (both not shown), and the like are installed in a casing (not shown) to constitute an outdoor unit.

The outdoor heat exchanger 5 has a notch 9 on the windward front surface by arranging fins 7 and 8 of different lengths alternately in parallel in the airflow direction shown by the arrow 6, and heat exchanger tubes are arranged perpendicularly to the fins 7 and 8. 10 is inserted. The air-side heat transfer surfaces of the fins 7 and 8 of the outdoor heat exchanger 5 and the heat transfer tubes 10 are treated with boehmite or coated with a synthetic silica-containing surfactant to make them hydrophilic.

Further, in the notch 9, the temperature sensing part of the temperature sensor 11 is held between the fins 7 and 8 by a support plate 12 having low thermal conductivity such as plastic.
1 and the support plate are also subjected to hydrophilic treatment in the same manner as the outdoor heat exchanger. The temperature sensor 11 is located inside the windward end of the fin 7, that is, closer to the fin 8.

In addition, 13 is a refrigerant temperature sensor attached to the bend part of the heat exchanger tube 10 in order to detect the refrigerant temperature of the outdoor heat exchanger.

Next, the action and effect will be explained.

First, during heating operation, frost formation occurs on the outdoor heat exchanger 5, that is, the evaporator, and as the operation continues, the air volume decreases due to the frost layer, so the evaporation temperature detected by the refrigerant temperature sensor 13 is As shown in Figure 4, it decreases as the operating time increases. On the other hand, the temperature sensor 11 provided in the notch 9 on the windward front surface of the outdoor heat exchanger 5 detects the outside air temperature during a considerable period of operation, and the frost layer grows and the notch 9 becomes a frost layer. When covered, the temperature of the frost layer is detected, and as shown in FIG. 4, the temperature rapidly decreases from point B.

Therefore, the temperature sensor 1 provided in the notch 9
If Δt is set as the difference between the temperature detected in step 1 and the temperature detected by the refrigerant temperature sensor 13, and the defrosting operation is started when this temperature difference is reached, (1) frost formation is always detected. So,
There is no need to run a defrost operation even though there is no frost.

(2) Since the amount of frost that accumulates on the outdoor heat exchanger 5 until the notch 9 and the temperature sensor 11 are covered with a layer of frost is approximately constant under all outside air conditions, the defrosting operation time can be set using a timer. Even if set, heating operation will not be restarted until the frost layer has completely melted.

From the above, the operation of the heat pump can be optimally controlled, and its performance is significantly improved.

Next, since the air-side heat transfer surface of the outdoor heat exchanger 5 and the temperature sensor 11 are subjected to hydrophilic treatment, during defrosting operation, frost melt water flows to the fins 7 and 8 and the temperature sensor 1.
It falls as a thin film of water without forming bridges or remaining as water droplets.

Therefore, after resuming heating operation, temperature sensor 1
There is no possibility that the detected temperature will drop due to evaporation of the water droplets remaining in the sensor 1, resulting in malfunction. In addition, since the entire air-side heat transfer surface of the outdoor heat exchanger 5 is subjected to hydrophilic treatment, the state of the heat transfer surface of the temperature sensor 11 section is the same as that of other heat transfer surface portions. 5. The entire frosting state can be detected correctly.

Further, the temperature sensor 11 can detect the outside air temperature when there is condensation on the outdoor heat exchanger 5 during heating operation or when the outdoor heat exchanger 5 functions as a condenser during cooling operation. This provides versatility, such as being able to control blowers and compressors.

In this embodiment, a notch was provided in the entire front surface on the windward side of the outdoor heat exchanger, but it goes without saying that the same effect can be obtained even if only the temperature sensor installation part is notched.

Effects of the Invention As described above, the outdoor unit of the heat pump of the present invention has a hydrophilic treatment consisting of fins arranged in parallel with cutouts on the front surface on the windward side and heat transfer tubes inserted perpendicularly to the fins. Since the temperature sensor which has been subjected to hydrophilic treatment is installed in the notch portion of the outdoor heat exchanger, it has the following effects.

(1) The heat pump operation can be optimally controlled by correctly detecting frost formation conditions such as the presence or absence of frost formation and the amount of frost formation, thereby significantly improving performance.

(2) During defrosting operation, frost-melted water falls as a thin film, so there is no malfunction even after heating operation is resumed.

(3) Temperature sensors can also be used to detect outside temperature.

[Brief explanation of drawings]

Fig. 1 is an outdoor unit of a heat pump showing a conventional example, Fig. 2 is a perspective view of an outdoor unit of a heat pump showing an embodiment of the present invention, and Fig. 3 is Fig. 2A.
FIG. 4 is an enlarged detailed view of the portion and is an explanatory diagram of the effect of the present invention. 5... Outdoor heat exchanger, 7, 8... Fin, 9...
... Notch portion, 10 ... Heat exchanger tube, 11 ... Temperature sensor, 12 ... Support plate.

Claims (1)

[Scope of Claims] 1 Between the fins of the notch of an outdoor exchanger consisting of fins arranged in parallel with a notch provided on the windward front surface and a heat transfer tube inserted perpendicularly to the fins, An outdoor unit of a heat pump that holds a temperature sensor using a support plate with low thermal conductivity such as plastic. 2. The outdoor unit of a heat pump according to claim 1, wherein the outdoor heat exchanger and the temperature sensor are subjected to hydrophilic treatment.