CN201203206Y - A multi-tank heat storage device for combined heating with solar energy and heat pumps - Google Patents

Abstract

A multi-tank heat storage device for combined heating with solar energy and heat pumps. The system is equipped with 2 to 5 parallel water storage tanks, and each water storage tank is equipped with a solenoid valve on the water supply or return water main pipe, and the water inlet or There is also a solenoid valve on the water outlet branch pipe, and a temperature sensor is installed at the bottom of each hot water storage tank; the hot water connecting pipe enters from the bottom of the hot water storage tank and comes out from the upper part, and connects each hot water storage tank in series; the solar collector The water supply and return pipe of the heat pump is connected with the water supply and return main pipe of the parallel heat storage tank at the end close to the cold water inlet, and the heat pump water supply and return pipe is connected with the water supply and return main pipe of the parallel heat storage tank at the other end. The system is equipped with heat pump charging, solar charging, and combined solar and heat pump heating; the heating mode can be selected arbitrarily according to the weather conditions, making full use of solar energy and off-peak electricity, and has the advantages of flexible control and low operating costs.

Description

A multi-tank heat storage device for combined heating with solar energy and heat pumps

technical field

The utility model relates to the technical field of solar heat utilization, in particular to a multi-water-tank heat storage device for combined heating of solar energy and a heat pump.

Background technique

With the rapid development of my country's economy, the problem of energy shortage is becoming more and more obvious. At the same time, with the improvement of people's living standards, the consumption of domestic hot water is also increasing rapidly. How to reduce the consumption of non-renewable energy without affecting people's quality of life has become a social concern. As a green renewable energy source, solar energy has been widely used in domestic hot water supply. Since the solar radiation varies day and night and is greatly affected by weather conditions, a heat storage tank and an auxiliary heat source are almost necessary components. At present, many solar water heating systems use electric heating as an auxiliary heat source, which not only consumes a lot of electric energy, but also puts a lot of pressure on the peak load of the power grid. Since the coefficient of performance (COP) of the heat pump is greater than 1, generally between 2 and 6, using the heat pump as an auxiliary heat source will greatly reduce power consumption. In the prior art, after the combination of heat pump and solar energy, due to the difficulty in matching and coordinating the heat pump heating, solar heating, and hot water storage tank, the efficiency of the solar collector is often greatly reduced, and the effective heat collected is very little, resulting in the system mainly relying on the heat pump heating. Therefore, a multi-tank heat storage device with combined heating of solar energy and heat pumps has been developed, so that it can not only make full use of solar energy, ensure the efficient operation of the heat collector, and save electricity, but also can make full use of the cheap low-peak electricity at night to save operation. At the same time, it is a very urgent and meaningful work to reduce the peak load pressure of the public power grid.

Utility model content

The utility model discloses a multi-tank heat storage device for combined heating of solar energy and a heat pump, the purpose of which is to overcome the difficulty in matching and coordinating the solar heating and heat pump heating in the prior art after the heat pump and solar energy are combined, which often makes the solar heat collector The efficiency is greatly reduced, and it is difficult to make full use of the disadvantages of low valley electricity at night. The utility model uses solar energy and a heat pump to prepare hot water, so that the device can use solar energy and low valley electricity at night for heating as much as possible, saving electricity and ensuring the collector. Efficient operation greatly reduces the peak load pressure of the public power grid.

A multi-tank heat storage device for combined heating of solar energy and heat pumps, characterized in that: 2 to 5 heat storage tanks are sequentially connected in parallel on the loop between the solar heat collector and the heat pump, and each heat storage tank supplies water or There is a solenoid valve on the return water main pipe, and a solenoid valve on the water inlet or outlet branch pipe, and a temperature sensor is installed at the bottom of each hot water storage tank; Each heat storage tank is connected in series; the water supply and return pipe of the solar collector is connected to the main pipe of water supply and return of the parallel heat storage tank at the end close to the cold water inlet, and the water supply and return pipe of the heat pump is connected to the parallel heat storage tank at the other end. The water supply and return mains are connected.

The volumes of the various hot water storage tanks can be equal or different. When the foundation load can meet the requirements and the space permits, multiple heat storage tanks are placed side by side, which can reduce the heat dissipation loss of the water tanks.

The heat pump may be an air source heat pump, a ground source heat pump or a water source heat pump.

The utility model can be charged in three modes:

1) The heat pump is charged separately

When it is known from the weather forecast that the next day's solar radiation is very low (rainy day), the heat pump will be started on the same night to charge the water tanks with low-peak electricity;

2) Solar energy is charged separately

When the solar collector can heat a sufficient amount of cold water to the required temperature on a sunny day (this usually occurs in summer, autumn, and spring), and the weather station predicts that the next day will be sunny, the heat pump will basically not work. During the day, solar collectors are used to charge the water tanks.

3) Combined heating with solar energy and heat pump

If the solar collector cannot heat enough hot water to the required temperature even on a sunny day (this can happen for many reasons, such as a small solar collector area, insufficient solar radiation in winter or low outside air temperature), then In the evening of the same day, the heat pump is started, and the low-peak electricity is used to charge 1 to 2 water tanks close to the heat load end. The next day, solar energy is used to heat the rest of the water storage tanks during the day. If the temperature does not meet the requirements, then Heated to the required temperature with a heat pump.

When the temperature at the bottom of the water tank is close to the temperature of the charging water or reaches the predetermined temperature, it is considered full.

The order in which the solar heat collectors or heat pumps charge the heat storage tanks is from the water tank with the hot water supply pipe to the water tank with the cold water inlet pipe.

Advantage and positive effect of the present utility model are:

1) It can combine the advantages of solar energy and heat pumps to maximize the use of solar energy and off-peak electricity under various weather conditions, save electricity, reduce operating costs, and reduce the peak power load of the power grid.

2) By adopting the method of parallel heat storage of multiple water tanks, the concentrated load and occupied space of the water tanks can be dispersed, so that the layout of the water tanks has more choices and flexibility.

3) The temperature stratification between water tanks is beneficial to improve the operating efficiency of solar collectors and heat pumps.

Description of drawings

Fig. 1 is a schematic diagram of the system structure of one of the utility model application embodiments;

Fig. 2 is a schematic diagram of the system structure of the second application embodiment of the utility model.

1: Solar collector, 2: Heat pump, 3: Collecting heat pump, 4: Heat pump loop circulation pump, 5: Expansion tank, 6: Hot water connection pipe; V1, V2, V3 water tank branch pipe solenoid valve, V4, V5 Solenoid valve in charge of the water tank, V6, V7 preset open pressure differential check valves, V8, V9 check valves; S1, S2, S3 hot water storage tanks, T1, T2, T3, T4, T5 temperature sensors.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail.

Example 1:

Each heat storage tank of the utility model has the same volume; the heat pump adopts an air source heat pump.

The structure of multi-tank solar-heat pump composite hot water system is shown in Figure 1. The whole system mainly includes three parts: solar heat collection loop, heat storage tank group, and heat pump heating loop. The solar heat collection loop includes solar heat collector 1, temperature sensor T4, heat collection water pump 3, and check valve V8; the heat pump heating loop includes heat pump 2, temperature sensor T5, check valve V9, and heat pump loop circulation pump 4 ; In the heat storage tank group, the number of heat storage tanks should be at least 2, not more than 5, and 3 are used in this embodiment, which are respectively heat storage tank S1, heat storage tank S2, and heat storage tank Box S3. Solenoid valve V4 and solenoid valve V5 are set on the return water main pipe between adjacent heat storage tanks, and solenoid valves V1, V2, V3 are also set on the return water branch pipe of each heat storage tank. The temperature sensors at the bottom of the tank are respectively T1, T2, and T3; the hot water connecting pipe 6 enters from the bottom of each heat storage tank and comes out from the top, connecting the three heat storage tanks in series; The hot water connecting pipes between them are also connected with the check valves V6 and V7 with preset opening pressure difference respectively. Connected, the water supply and return pipe of the heat pump heating loop is connected at the other end with the water supply and return main pipe of the parallel heat storage tank S3. The expansion tank 5 is used to accommodate the volume change of the water in the solar heat collection loop, the heat storage tank group, and the heat pump heating loop due to temperature changes.

The charging of the heat storage tank in the utility model is divided into three kinds of modes.

The first mode is solar heating alone, and the heat storage tanks S3, S2, and S1 are charged in sequence. The specific method is: (1) Open the solenoid valves V3, V4, V5, close the solenoid valves V1, V2, start the solar heat collector pump 3, and use the solar heat collector to charge the heat storage tank S3. (2) After a period of time, when the temperature T3 in S3 reaches the requirement, the heat storage in S3 is completed; close the solenoid valves V5 and V3, open the solenoid valve V2, and charge the heat storage tank S2. (3) After a period of time, when the temperature T2 in S2 reaches the requirement, the charging of S2 is completed. (4) Close the solenoid valves V2 and V4, open the solenoid valve V1, charge the heat storage tank S1, and complete the charge when the temperature of S1 reaches the requirement. This mode is suitable for sunny days and the collector can heat a sufficient amount of cold water to the required temperature, such as sunny days in summer, spring, and autumn.

The second mode is the independent heating mode of the heat pump, which charges S3, S2, and S1 in sequence. Use this mode when it is known from the weather forecast that the next day's solar irradiance is very low (rainy day). The specific method is as follows: (1) Open the solenoid valve V3, close the rest of the solenoid valves, and charge S3 with heat pump. (2) After a period of time, when the temperature in S3 reaches the requirement, close the solenoid valve V3, open the solenoid valve V2, and charge S2 with heat. (3) After a period of time, when the temperature in S2 reaches the requirement, close the solenoid valve V2, open the solenoid valve V1, and charge S1 with heat. (4) When the temperature of S1 reaches the requirement, the charging is completed. This mode is suitable for rainy days.

The third mode is the joint heating mode of solar energy and heat pump. The specific method is: (1) At night, after the heat consumption peak (usually after 22 o'clock), open the solenoid valve V3 and close the other solenoid valves. The heat pump is turned on to charge the water tank S3 with low-peak electricity. (2) Turn off the heat pump and solenoid valves V3 and V5 at first during the day and open the solenoid valves V2 and V4 to charge S2 with solar energy. (3) Because the solar irradiance is low, the temperature of the water tank cannot meet the heat requirement. Therefore, after the solar energy finishes charging S2, open the solenoid valves V5 and V2, close the solenoid valves V3 and V4, and reheat S2 with a heat pump make it meet the requirements. (4) While the heat pump is charging S2, open the solenoid valve V1 to charge S1 with solar energy. After the solar energy finishes charging S1, open the solenoid valve V4, close the solenoid valves V2 and V3, and use the heat pump to reheat S1 to meet the requirements. This mode is used when the heat collection area in the system is insufficient, and all the cold water cannot be heated to the required temperature even on a sunny day, or when the solar irradiance of the next day is low from the weather forecast, and solar heating alone cannot fully meet the heating requirements.

Example 2:

Figure 2 is a schematic diagram of the system of the second embodiment of the utility model. Compared with the first embodiment, the difference is that a heat exchanger is added in the water tank, and the water gets heat from the water tank through the heat exchanger when taking heat. , In this way, the domestic hot water is separated from the water in the hot water storage tank, and the water quality of the domestic hot water is more guaranteed. At this time, there is no need to install a check valve with a preset opening pressure difference on the hot water connecting pipe.

Claims (3)

1. A multi-tank heat storage device for joint heating of solar energy and heat pump, characterized in that: 2 to 5 heat storage tanks are sequentially connected in parallel on the loop between the solar heat collector and the heat pump, and each heat storage tank There is a solenoid valve on the water supply or return main pipe, and a solenoid valve on the water inlet or outlet branch pipe. A temperature sensor is installed at the bottom of each hot water storage tank; the hot water connecting pipe enters from the bottom of the hot water storage tank and comes out from the upper part. And connect each heat storage tank in series; the water supply and return pipe of the solar collector is connected to the main water supply and return water pipe of the parallel heat storage tank at the end close to the cold water inlet, and the water supply and return pipe of the heat pump is connected to the parallel heat storage tank at the other end. The water supply and return main pipes of the water tank are connected. 2. A heat storage device with multiple water tanks for combined heating of solar energy and heat pumps according to claim 1, characterized in that the volumes of the heat storage tanks can be equal or unequal. 3. A multi-tank heat storage device for combined heating of solar energy and heat pumps according to claim 1, characterized in that: said heat pumps can be air source heat pumps, ground source heat pumps or water source heat pumps.

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