JPS60213773A - Solar heat collection device - Google Patents

Abstract

PURPOSE:To permit to prevent the frequent ON, OFF of a compressor when atmospheric temperature is low and obtain the temperature rise of supplying hot- water by extending the time of heat collecting operation by a method wherein a control unit, receiving the output of a temperature sensor, is provided with a given time of insensitive band for detecting the inlet port temperature of a heat collector upon starting the heat collecting operation. CONSTITUTION:In case the atmospheric temperature is reduced or the refrigerant evaporating capacity of a heat collector 1 is reduced due to generation of frosting in the heat collector 1, the inlet temperature of the heat collector 1 is also reduced and the heat collecting operation is stopped when the temperature sensor 12 has arrived at a set temperature T1 in order to prevent the liquid returning operation of the compressor 3. On the other hand, the inlet temperature of the heat collector 1 arrives at a temperature lower than the temperature T1 once and is increased again after some period of time when the heat collecting operation is started under a low atmospheric temperature, however, the device is provided with the given time of band insensitive for detection of inlet temperature of the heat collector 1, therefore, the reduction of inlet temperature of the heat collector 1 upon starting is not detected. After passing the insensitive band, the inlet temperature TE of the heat collector is compared with the set temperature T1 and the operation is stopped in case TE<=T1 while the heat collecting operation is continued in case TE>T1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a solar heat collecting device comprising a heat collecting circuit that collects solar heat and atmospheric heat, and a hot water heating circuit that uses the collected heat to raise the temperature of water. This relates to heat collection operation control at low outside temperatures.

Structure of a conventional example and its problems A conventional solar heat collecting device of this type is shown in FIG. 1
is a heat collector that evaporates refrigerant using solar heat and atmospheric heat;
2 is an accumulator, 3 is a compressor 1, 4 is a condenser for condensing refrigerant, 5 is a thermostatic expansion valve, 6 is a temperature-sensitive tube, and 7 is a capillary tube. Further, 8 is a heat exchanger that absorbs heat released from the refrigerant from the condenser 4, 9 is a pump, and 10 is a heat storage tank. In the above configuration, an outside temperature sensor 11 is provided to prevent compressor liquid return operation at low outside temperatures, and operation control is used in which the heat collection operation is turned on and off depending on the set temperature. However, according to the above method, the outside temperature may not be detected accurately depending on the installation conditions of the outside temperature sensor 11, and the weather conditions such as solar radiation and outside air wind speed are not included, so even though heat collecting operation is possible, This method is indirect and cannot be said to be sufficient as a method for detecting the prevention of compressor fluid return during low outside temperature operation without heat collection operation.

Further, as a method for detecting the prevention of compressor liquid return during low outside temperature operation, a method of detecting the temperature at the outlet of the heat collector 1 (point A) can be considered. In other words, when the outside temperature is low, as the refrigerant evaporation capacity of the collector 1 decreases, unevaporated refrigerant begins to pass through the outlet of the collector 1, and the temperature at the outlet of the collector 1 decreases. If the temperature drops below the set temperature, the heat collection operation is stopped. However, in this type of system, the temperature at the outlet of the heat collector 1 may fluctuate instantaneously due to load fluctuations caused by instantaneous solar radiation or changes in outside air wind speed. There was a problem in that it was impossible to determine whether the temperature drop was due to instantaneous load fluctuations, which could prevent liquid spooling operation with accumulator 2, or whether the temperature drop was due to a continuous liquid spooling state, where accumulator 2 could not prevent liquid spooling operation. . In comparison, the heat collector 1 population temperature (B
Point) has smaller temperature changes due to instantaneous load fluctuations due to changes in solar radiation or outside air wind speed than the temperature at the outlet of the collector 1 (point A), and the population temperature of the collector 1 decreases as the refrigerant evaporation capacity of the collector 1 decreases. In order to stop the heat collection operation when the heat collector 1 population temperature TE becomes lower than the set temperature Ti, the heat collection circuit temperature is directly detected and the liquid return operation of the compressor 3 is controlled by the influence of instantaneous load fluctuations. This can be prevented. However, when the heat collection operation is started at a low outside temperature, the temperature TE between the pressure reducing device and the heat collector 1, which is the population temperature of the heat collector 1, is lower than the set temperature Ti for about 2 to 3 minutes as shown in Figure 2. becomes low and then T
It becomes stable as E>TI. This means that even if heat collection operation is actually possible when the outside air temperature is low, there may be a situation where heat collection operation is not performed due to a temporary drop in the temperature of the heat collector 1 at startup. There are problems such as not being able to obtain a sufficient temperature rise value for hot water supply due to a decrease in operating time, and problems such as a decrease in operating efficiency and a decrease in system reliability due to frequent ON and OFF of the compressor 3. Ta.

Purpose of the Invention The present invention is intended to solve the problems of the prior art, and aims to increase the heat collection operation time at low outside temperatures, increase the temperature of hot water supply, prevent a decrease in system operating efficiency, and improve reliability. This is the purpose.

Structure of the Invention In order to achieve this object, the present invention is provided with a temperature sensor that detects the temperature at the inlet of the heat collector, and a control device that receives the output from the temperature sensor detects the temperature at the inlet of the heat collector at the time of starting the heat collection operation. This configuration has a detection dead zone for a certain period of time. With this configuration, the decrease in the collector inlet temperature that occurs during a certain i hour when starting the heat collection operation at low outside temperatures is not detected, but the subsequent collector inlet temperature TE tt@ is detected and the compression The relationship with the collector inlet temperature Ti that causes liquid backflow in the machine is TE>TI
If so, heat collection operation is performed, and if TE≦TI, heat collection operation is stopped.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Note that the same parts as in the conventional example are given the same numbers. 12 is a temperature sensor that detects the inlet temperature of the heat collector 1, and 13 is a control device that has a dead zone in which the output of the temperature sensor 12 is not detected for a certain period of time after the heat collection operation is started. Next, the operation of the solar heat collecting device having the above configuration will be explained. The high-temperature, high-pressure refrigerant gas compressed by the compressor 3 flows into the condenser 4, and uses the heat of condensation to heat and raise the temperature of the low-temperature water sent by the pump 9 of the hot water heating circuit, and stores it in the heat storage tank 10. On the other hand, the refrigerant that has been liquefied by being deprived of the heat of freezing and condensation flows into the thermostatic expansion valve 5 and the capillary tube 7 (pressure reducing device), is depressurized, flows into one heat collector, absorbs solar heat and atmospheric heat, and evaporates into gas. It passes through the accumulator 2 and returns to the compressor 3. When the outside air temperature decreases or when frost forms on the heat collector 1 and the refrigerant evaporation capacity of the heat collector 1 decreases, the population temperature of the heat collector 1 also drops and when the temperature sensor 12 reaches the set temperature T'l, the compressor Heat collection operation is stopped in order to prevent liquid return operation in step 3.

In addition, when the outside temperature is low, the temperature of the collector 1 decreases once below the TI temperature due to the phenomenon of refrigerant stagnation in the compressor 3 when starting the heat collection operation, and then rises after a while. At the time of startup of operation, the detection of the population temperature of the heat collector 1 is equipped with a control device that has a dead zone for a certain period of time.
A drop in population temperature is not detected. Then, after passing through the dead zone, the temperature TE of the heat collecting mold is compared with the set temperature Ti.
If E≦TI, operation is stopped; if TE > TI, heat collection operation is continued. In the above action, when the heat collecting operation is started, since the control device has a detection dead zone for a certain period of time for the detection of the heat collector 1 population temperature, once the heat collector 1 population temperature TE becomes TE≦
Even if the temperature reaches 'r1, the heat collection operation will not be stopped, and in order to determine whether the heat collection operation should be stopped or intermittent after the dead zone, the heat collection operation time can be expanded within the range where the compressor 3 does not perform liquid return operation.
This has the effect of increasing the temperature of hot water. Note that TE≦ at startup
Operating with Ti during the dead zone is short and the accumulator can sufficiently prevent liquid from returning to the compressor.

Effects of the Invention The present invention prevents frequent ON and OFF of the compressor at low outside temperatures by providing a dead zone of the temperature of one heat collector for a certain period of time at the start of heat collection operation in the control device. This has the effect of preventing a decrease in operating efficiency and system reliability, and increasing the temperature of the hot water supply by extending the heat collection operation time when the outside temperature is low.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a conventional example of a solar heat collecting device, Fig. 2 is a characteristic diagram of the collector inlet temperature of the solar heat collecting device at startup, and Fig. 3 is according to an embodiment of the present invention. FIG. 2 is a configuration diagram of a solar heat collecting device. 1... Heat collector, 2... Accumulator, 3... Compressor, 4... Condenser, 5...
... Temperature expansion valve, 12 ... Temperature sensor, 1a ... Control device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2: Sweet I Figure 3

Claims (1)

[Claims] a heat collection circuit consisting of a heat collector, an accumulator, a compressor, a condenser, and a pressure reducing device; a heat exchanger that exchanges heat with the condenser;
It consists of a hot water heating circuit consisting of a pump and a heat storage tank, and is equipped with a temperature sensor that detects the inlet temperature of the heat collector, and a controller that receives the output of this temperature sensor. A solar heat collection device configured to have a temperature dead zone for a certain period of time.