JPS6341767A - Heat pump hot water supply system - Google Patents

Abstract

PURPOSE:To provide a compact and safe hot water supply system which can save energy and does not fall short of hot water supply by modulating the set temperature to the maximum temperature when the hot water supply peaks by predicting the time of the peek of the hot water supply load from the past data of hot water supply consumption for each hour, and controlling the temperature to the user's set temperature at other times. CONSTITUTION:Heat is absorbed from the atmosphere in a vaporizer 2 and the refrigerant is compressed in a compressor 4 which exchanges heat with water in a condor!ser 6 by a forced circulation pump 7. The refrigerant having exchanged heat in the condenser 6 passes a refrigerant pipe 8 through ar! expansion valve 5 back to the vaporizer 2. By estimating the day's hot water supply load pattern from the average value of hot water consumption for each day and hour in a week determined from the past recor.ds over several weeks, an anticipated time of completion of heating is predicted by using the functions of the capacity of appliance and existing temperature of hot water in the reservoir. In order to bring the temperature of the hot water reservoir to the maximum set temperature when the load peaks, the set temperature is modulated to the maximum set temper.ature if the present time is between the predicted heating time and the ending time of the peak so that the peak load requirement can be mot. Once the peak hours are over, the set temperature is returned to the user's set temperature. Therefore, a safe domestic hot water supply system which can save energy and does not fall short of hot water supply can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hot water supply system in a house or the like.

BACKGROUND OF THE INVENTION Conventionally, there have been two types of hot water supply systems in houses: collective type in apartment complexes and individual type installed in each unit. As shown in Figure 2, a collective hot water supply system uses a heat source device 1 to supply n hot water tanks 3 for the entire residential building.
Either the hot water was heated to a set temperature and the hot water was circulated to supply hot water to each unit, or as shown in Figure 3, high-temperature heat source water was produced in a heat source unit 1 and heat exchanged with a heat exchanger in each unit and then supplied.

On the other hand, the door-to-door type has a water heater in each home, and the most common type is an instantaneous gas water heater.

Examples of electric water heaters include electric water heaters, heat pump water heaters, and solar water heaters. Electric water heaters use late-night electricity to heat the water at night with an electric heater, and then store high-temperature hot water for use the next day. A heat pump water heater uses air as a heat source and uses a refrigeration cycle to pump heat and heat water. Water heated by a condenser is stored in a hot water tank. Solar water heaters either collect solar heat directly with a circulation pump or heat a refrigerant with solar heat and heat water in a refrigeration cycle.

Problems to be Solved by the Invention In conventional systems such as those mentioned above, firstly, collective hot water systems have the advantage that a constant hot water temperature can be obtained at any time and there is no need to worry about running out of hot water. In order to constantly circulate hot water or high-temperature water even when not in use,
The heat loss from the piping is large, and the conveyance power is also large, so it is not an energy-saving system. In contrast to such collective-type water heating systems, door-to-door systems do not require transport power and have less heat loss, but gas systems are sometimes difficult to adopt in apartment buildings due to safety issues. In addition, in systems that use electricity, an electric heater has a low coefficient of performance, and if a heat pump is used, the coefficient of performance is generally high, but if the artificial water temperature of the condenser is high or there is a lot of intermittent operation, the coefficient of performance is low. Become.

Means for solving the problem In order to solve this problem, we used a heat pump water heater that connected the evaporator, compressor, condenser, and hot water storage tank that stores the water heated by the condenser with refrigerant piping. Predicts the time when the overall peak of hot water supply will occur in the future from the time-by-time hot water usage data, and controls the set temperature so that it is at the maximum temperature during the peak of the hot water supply load, and at the user's set temperature at other times. .

How it works This method saves energy and prevents you from running out of hot water.
A safe residential hot water system can be provided.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings. FIG. 1 is a representative example of the system.

Heat is sucked up from the atmosphere by an evaporator 2, a refrigerant is compressed by a compressor 4, and heat is exchanged with water in a condenser 6 by a forced circulation pump 7. The water heated by heat exchange must be kept from breaking the temperature stratification within the hot water tank 3. This requires that the outlet temperature of the water heat exchanged in the condenser 6 be the same as that of the upper layer of the hot water tank 3. Either reduce the circulating flow rate to maintain the same temperature, or reduce the temperature of the upper layer of the hot water tank 3 so that the temperature in the upper layer of the hot water tank 3 does not drop even if the temperature after heat exchange is low.
Make sure to return it below the middle layer. The refrigerant that has undergone heat exchange in the condenser 6 passes through the refrigerant pipe 8t, passes through the expansion valve 5, and is sent to the evaporator 2 again.

In order to operate such a system efficiently, it is necessary to keep the artificial water temperature in the condenser 6 as low as possible so as not to accumulate wasteful heat in the hot water storage tank 3. Therefore, when we look at the characteristics of residential hot water supply loads, we find that they are greatly influenced by their lifestyle patterns. The biggest one is filling the bathtub with water, and this is when the biggest load occurs during the day. It is at this time that a high hot water supply temperature is required, and by mixing with water the temperature required for the bath is achieved. This is m'I of the hot water used when filling water! : By reducing the hot water tank 8
In addition, a high hot water temperature is required to prevent the water temperature from dropping in the bathtub due to reheating. Other uses include cooking, stagnation, and showering, which do not require such high temperatures and do not require a large amount of hot water.

Control corresponding to this is shown in FIG. The hot water supply load pattern for that day is predicted based on the average value of hot water consumption by day of the week and time of the past several weeks, and the preheating time is set based on the equipment's capacity at that time so that the hot water tank reaches the maximum set temperature at the peak time. It is predicted based on the hot water storage tank temperature, and when the current time is between the preheating time and the peak end time, the set value is raised to the maximum set temperature to prepare for the peak of hot water supply. The set temperature is lowered to the user's set temperature after the predicted peak time period has passed.

At this time as well, there is hot water at a higher temperature than the previous maximum setting in the upper and middle layers of the hot water storage tank, so even if there is a request for high temperature hot water after the expected peak period, it can be adequately met.

The temperature of the hot water stored in this way varies depending on how each dwelling unit uses it. Figure 5 shows a typical example of the change in hot water tank temperature on -day in a system where the hot water temperature is set at a constant maximum temperature. In the above figure, the dotted line represents the hot water supply load. be.

The largest load occurs after 8:00 pm, and this is due to filling the bath with water. -The temperature is maintained at almost the set temperature through the mouth, but the temperature gradually drops during the night due to heat loss to the surroundings. The figure below shows the amount of heating.5
The hot water tank is heated from time to time to increase the temperature of the water in the tank. In other words, in order to maintain the hot water temperature throughout the day, heat retention operation is required. At this time, low efficiency operation occurs. Furthermore, FIG. 6 shows changes in the temperature of the hot water storage tank in a system that changes the set temperature in anticipation of the peak of the hot water supply load.

The temperature setting is changed to the maximum temperature during the peak hours starting at 7:00 pm, and during the day the temperature is set by the user. Comparing the heating amount in Figure 5, the low efficiency operation around 5 o'clock and before 12 o'clock has disappeared, and overall there has been less intermittent operation and the average hot water tank temperature has decreased.
Heat loss is also reduced, making it possible to operate the heat pump with high efficiency, resulting in overall energy savings.

Effects of the invention A water heater equipped with this control enables an energy-saving and safe hot water system for apartment buildings that never runs out of hot water.
Its practical effects are significant.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a heat pump water heater according to an embodiment of the present invention, Fig. 2 is a diagram of a hot water supply system for an apartment complex in which one hot water storage tank is installed in the entire residential building, and Fig. 3 is a diagram of each unit of the apartment complex. Figure 4 is a schematic flowchart of the control, Figure 5 is a characteristic diagram showing the change in hot water tank temperature during set value constant control, and Figure 6 is a diagram of a hot water supply system for an apartment complex with a heat exchanger. , is a characteristic diagram showing the temperature change of the hot water storage tank when the set value is changed. 1... Heat source machine, 2... Evaporator, 3... Storage tank, compressor, 6 Name of condenser agent. Patent Attorney Toshio Tsuchinakao 1 person 2- Evaporator 3- Hot water storage tank 4- Compressor 6-11-alt compressor Figure 1 Figure 2 1-1!, Gengu 3-ff
Yu 1 meeting Figure 3 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) A heat pump with an evaporator, a compressor, a condenser, and an expansion valve connected by refrigerant piping, and a forced circulation pump have a hot water storage tank that stores hot water heated by the above condenser, and the past time-based hot water supply usage A heat pump water heater that predicts the time of future peak hot water supply load for each day of the week based on volume data and sets the heating time to meet that time. (2) The heat pump hot water supply according to claim 1, which has control to set the temperature of the hot water in the hot water storage tank to the maximum during peak hot water supply load, and to change the temperature to the temperature desired by the user at other times. Machine.