JPH02130362A - Defrosting control method for air-cooled heat pump type hot water feeder - Google Patents

Abstract

PURPOSE:To prevent wasteful defrosting operation by completing the defrosting operation on condition that temperature on the surface of a pipe of an air side heat exchanger has rise up to the level of a predetermined temperature, without waiting for the increase of a high-pressure side pressure and the lapse of a predetermined period, in the case where the high-pressure side pressure does not increase even if frost formed on the air side heat exchanger is thawed. CONSTITUTION:When a contact 15a2 is closed, a coil 13 of a timer for counting a defrosting operation time is excited, and the timer counts the defrosting operation time. During the period of this operation time, if a temperature on the surface of a pipe for an air side heat exchanger rises to close the contact point 11 of a thermostat or if a high-pressure side pressure increases to close the contact 12 of a high-pressure switch, a coil 18 of an auxiliary relay for defrosting completion is excited to open its contact 18b, and then a defrosting instruction is cancelled. Further, even if a temperature on the surface of the pipe and a high-pressure side pressure do not increase, a contact 13a is closed when the defrosting operation time reaches a predetermined period of time set to the timer 13, whereby the defrosting instruction is cancelled in a similar manner to return to a hot water feed operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a defrosting control method in an air-cooled heat pump water heater.

[Conventional technology]

The conventional defrosting control method is Hitachi's cold heat pump type F9-
Unit length - Bismanial, Oni “CAM-8102”P
Z5. As described in P.26, Box removal control, the start of defrosting is as follows:
After the shortest defrost interval time has elapsed, a defrost command is issued when the pipe surface temperature of the air gIIl heat exchanger has decreased. It was designed to issue a command to end defrosting if the pressure rises above that level.

[Problem to be solved by the invention]

In the above conventional technology, the defrosting end command is issued after the longest defrosting time has elapsed or when the high pressure rises to a predetermined pressure, but as shown in Figure 4, the pipe surface temperature increases due to defrosting. As the pressure rises, the pressure on the high pressure side also rises, so there is no problem with conventional refrigeration cycles, but as shown in Figure 5, even if the pipe surface temperature rises, that is, even if the frost thaws, In a refrigeration cycle such as an air-cooled heat pump type water heater where high pressure does not rise, the high pressure does not rise to the specified pressure even though the division has actually finished, so the division continues until the maximum operation time. There was a problem with frost operation. The reason for this is that air-cooled heat pump water heaters are #
Because the volume of the refrigerant on the rk supply side differs greatly between the cooling operation and the defrosting operation (the air side heat exchanger is larger than the hot water supply heat exchanger), the air side heat exchanger is placed on the condenser side. Defrosting operation, which is used as a water heater, requires more refrigerant than hot water supply operation.For this reason, originally, the refrigerant was sealed in conjunction with defrosting operation, and the surplus refrigerant during hot water supply operation was stored in a liquid tank, etc. However, water heaters are mainly used to supply hot water, and it is uneconomical to install a tank or the like that drains a large amount of refrigerant just for defrosting.

Therefore, the temperature is determined within the necessary range that does not cause any problems in refrigerant-filled iVi and hot water supply operation, and that defrosts can be reliably performed. In other words, the defrosting operation is performed in a state where there is a shortage of refrigerant, and the pressure on the high pressure side does not rise sufficiently.

In such a refrigeration cycle, as in the conventional technology,
If the defrosting is completed by only removing + i time and increasing the high pressure side pressure, the high pressure side pressure will not increase even though the defrosting is completed, resulting in wasteful defrosting until the maximum defrosting time elapses. No exception! 6 I will continue driving.

An object of the present invention is to eliminate the above-mentioned problems and prevent unnecessary defrosting operations.

[Means to solve the problem]

In order to achieve the above purpose, if the high pressure does not rise even if the coating 1 of the air side heat exchanger is dissolved, the pipe surface of the air side heat exchanger is Defrosting is terminated on the condition that the temperature rises to a predetermined temperature.

[Effect]

As defrosting progresses and the frost melts, the surface temperature of the pipe on the air side heat exchanger outlet side increases.

Therefore, when the pipe surface temperature reaches a predetermined temperature during the defrosting operation, a defrosting end signal is issued.

As a result, even if the high pressure side pressure does not rise, it is possible to detect that the box has thawed and finish defrosting.
Wasteful ll&-: No need to drive 1m.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to Fig. 1, Fig. 2, and Fig. 8. ** Fig. 2 and Fig. 8 show the defrosting control method, and the horizontal axis represents the operating time, and the vertical axis represents the defrosting control method. shows the operating pressure of the high pressure side pressure switch and the pipe surface temperature of the air side heat exchanger. In addition, in this embodiment, the operating value of the high pressure switch for ending defrosting is 21 kg/am G, the temperature on the upper side of the pipe is 80°C, the surface temperature of the pipe for starting defrosting is -2°C, and the shortest defrosting interval time. is set to 60 minutes, and the maximum removal time is set to 6 minutes. The control method will be explained below. At point 1 in Figure 2, 60 minutes have passed since the start of defrosting, but the pipe surface temperature is over 12"C, so heating operation continues. At point 20, 60 minutes have passed since the heating operation started, and the pipe surface temperature continues to rise. is below -2℃, so defrosting is started.Defrosting is started and the high pressure side pressure is 21℃.
Since it reached 1 g/cs G, defrosting is finished at 80 points. This case occurs when the relative humidity is low and there is no actual RI layer frost, but only the pipe surface temperature becomes -2'C or less and the defrosting operation is started, so-called empty load removal operation. That is, since the heat exchange capacity on the exhaust heat side is small, the high pressure increases rapidly and there is a delay in pipe surface temperature detection, so the defrost end signal is issued based on the high pressure side pressure. At point 4 in Figure 8, after defrosting, 6
After 0 minutes, the pipe surface temperature is 12'C, so defrosting is started. The pipe surface temperature reached 30″G within a few minutes after defrosting started.
Since K has been reached, defrosting ends with 50 points. After 60 minutes, defrosting was started again at the 60 point, but this time, the high pressure side pressure was below 21 kg/as G and the pipe surface temperature was below 80°C, but the maximum defrosting time of 6 minutes had passed. Therefore, defrosting ends at 70 points. After another 60 minutes, if the pipe light surface is 12'C again, defrosting will start at point 8, and the above operation pattern of F1 will continue.

FIG. 1 μ shows an example of the defrosting control circuit of the present invention. 9 is a contact point of a timer that counts the hot water supply operation time, and has the function of tilting to the left side when hot water supply operation continues for a certain period of time, and tilting back to the right side after a while. 10V'i
This is the contact point of the thermostat that detects the air side heat '5F and the exchanger pipe surface temperature, and closes when the temperature drops. 1
1 is also a contact point of a thermostat that detects the surface temperature of the air side heat exchanger pipe, which closes when the temperature rises. 18 is a timer coil that counts the defrosting operation time, and 4 is its contact point. ■2 is the contact point of the high pressure side pressure switch, which closes when the high pressure rises. 15 is the coil of the auxiliary relay for defrosting start command, 15al+15azt';t
This is the point of contact. 18d is an auxiliary V- coil for commanding the end of defrosting, and 18b is its contact point. zO indicates a division-by-one circuit. Next, the operation will be explained.

When the hot water supply operation continues for a certain period of time, the contact 9 of the hot water supply operation timer falls to the left. At this time, if the surface temperature of the air side heat exchanger pipe is lower than a predetermined temperature, the contact 10 of the thermostat is closed. (If the temperature is high, it remains open, and the timer contact 9 falls to the right again.) Then, the coil 15 of the defrosting command auxiliary relay is energized, its contacts 158 and 15a2 are closed, and the coil 15 is Contact 1
Self-holding is achieved by 5al, and at the same time, the defrosting circuit zO is excited and begins defrosting operation. On the other hand, by closing the contact 15a2, the timer for counting the defrosting operation time #13
is energized and counts the defrosting operation time. During this operating time, if the pipe surface temperature of the air side heat exchanger increases and the thermostat contact 11 closes, or if the high pressure side pressure increases and the high pressure switch contact 12 closes,
The coil 18 of the auxiliary defrosting relay is energized, its contact 18b is opened, and the defrosting command is canceled. Furthermore, even if the pipe surface temperature and high pressure do not rise, when the defrosting operation time reaches the predetermined time (timer 13c), the contact 13a closes, and the defrosting command is canceled in the same way, returning to hot water supply operation. Become. From now on, the above driving pattern will continue.

As described above, according to this embodiment, the end of defrosting is controlled by the high pressure side pressure, the pipe surface temperature of the air side heat exchanger, and the maximum defrosting time, so the end of defrosting can be detected more reliably and at the same time. Even in a refrigeration cycle where the high-pressure side pressure does not rise during load-removal operation, such as in a water heater, the end of defrosting can be quickly detected, eliminating unnecessary defrosting operations.

[Effects of the Invention] According to the present invention, the end of defrosting is determined when any of the high pressure side pressure, pipe surface temperature, and longest defrosting operation time are satisfied. Since defrosting is properly completed due to insufficient defrosting and defrosting is completed due to defrosting operation time, wasteful defrosting operation can be prevented.

[Brief explanation of drawings]

FIG. 1 is a control circuit diagram of an embodiment of the present invention, FIGS. 2 and 8 are control explanatory diagrams of a defrosting control embodiment of the present invention, and FIG. 4 is a diagram showing conventional defrosting operation time and high pressure. FIG. 5 is a diagram showing the relationship between the defrosting operation time and the surface temperature of the high-pressure pressure vibrator, which is the object of current control. 1... The shortest divided by 4 intervals OO minutes have passed, but the pipe surface temperature is -2' (j or more) B -4+ 6-8... Defrosting begins 8, 5.7... Defrosting ends, 9...Contact point of timer for counting hot water supply operation time 10.i.11...Contact point of thermostat for air 1jlII heat exchanger pipe surface temperature dt 12.
...High pressure IA switch contact 18...Timer coil for counting defrosting operation time 13a...Timer 1
8 mA15...Auxiliary relay coil for defrosting command
15a1.15a2... Contact of auxiliary relay 15 1
8...Auxiliary ring coil for defrosting completion 18b...
・Supplementary Figure 1 114t-Note 771. Dou's Iku Yuru 131f IK Nakarei ■ Timer Coil p Old Man I Dan Yusuke Hibiki Lu's Carp (P Wood 1 Casting Sukiyaki Sushi - Carp J ShitZ 7ktr
kqpr period r tsuta t+nJi-I3kyu Timer I3's kick attack, 15a 1. tfo z sai t~f revli t-1r
th#@If3b @'Jforce I) L-tF3a#Concubine R
Plan 2UfU

Claims (1)

[Claims] 1.Equipped with a compressor, hot water supply heat exchanger, four-way valve, air side heat exchanger, pressure reducing device, liquid solenoid valve, suction pressure adjustment valve, and multiple check valves, and air side heat exchange during hot water supply operation. Heat is collected from the water heater and discharged to the hot water heat exchanger, and if frost forms on the air side heat exchanger due to the drop in outside air, the four-way valve is switched, heat is collected from the hot water heat exchanger, and the air In an air-cooled heat pump type water heater equipped with a refrigeration cycle that defrosts by discharging heat to the side heat exchanger, the signal to start defrosting in the defrosting operation described above is determined when the pipe surface temperature at the air side heat exchanger inlet is Defrosting begins after the temperature drops to a predetermined temperature and hot water supply operation continues for a certain period of time, and defrosting ends when the high pressure rises to a predetermined value, or when a certain period of time has elapsed from the start of defrosting. Alternatively, an air-cooled heat pump type characterized in that defrosting is terminated when any one of the pipe surface temperatures at the air side heat exchanger outlet (during defrosting) rises to a predetermined temperature. Defrosting control method for water heater.