CN206291511U - A kind of novel solar water heating system - Google Patents

Abstract

A new solar hot water system for secondary heating networks in district heating systems. The system includes: a control device, one or more solar heating subsystems, a hot water tank, a water pump and water pipes. The system uses solar energy to heat the return water of the secondary heating network, which improves the economy of heating. The system makes full use of solar thermal energy, which can greatly reduce carbon emissions.

Description

A new type of solar water heating system

technical field

A new solar hot water system for secondary heating networks in district heating systems. The system uses solar energy to heat the return water of the secondary heating network, which improves the economy of heating. The system makes full use of solar thermal energy, which can greatly reduce carbon emissions.

Background technique

With the improvement of environmental protection and energy saving awareness, solar water heaters, as a kind of white goods, have begun to enter thousands of households and are widely favored. In areas rich in solar energy, my country has generally begun to promote household solar water heaters to provide hot water. The performance of domestic solar water heaters fluctuates and intermittently with the solar energy supply period. During the rainy season and at night, the stored water capacity of domestic water heaters is often insufficient to fully meet the domestic hot water demand. Especially in rural areas with poor insulation measures, when hot water is needed in winter, the water heater on the roof becomes a decoration instead.

Considering that district central heating systems are commonly used in cities and towns in northern China. In the central heating system, the water supply temperature of the secondary heating network is generally between 60 and 80°C, which is very suitable for combining with solar water heaters. The invention proposes to combine the solar water heater with the secondary heating network, which can not only improve the economy of the central heating system, but also improve the efficiency of the solar water heater, and fully guarantee that users can get enough hot water.

Contents of the invention

The invention proposes a novel solar water heating system, which is characterized in that the system includes: a control device, one or more solar heating subsystems, a hot water tank, a water pump and water pipes; the solar heating subsystem includes a solar heating subsystem Subsystems and solar cold water side subsystems; solar heating subsystems include solar collectors, circulating water pumps, temperature sensors and water pipes; solar cold water side subsystems include pumping water pumps, temperature sensors, heat exchangers, valves, pressure sensors and water pipes; the control device communicates with solar collectors, heat exchangers, hot water tanks, valves, water pumps, temperature sensors and pressure sensors for control; the solar heating subsystem acts on the water supply pipe and the return water pipe between.

When there are multiple buildings in the heating area, a solar heating subsystem is arranged on the roof of each building.

The solar water heating system is located in the district heating secondary heating network. The solar water heating system extracts the heating return water with a lower temperature from the return water pipe of the heating network. Hot water is added to the water supply pipes of the heating network.

Multiple solar heating subsystems share a hot water tank, which is covered with thermal insulation material, and its capacity is determined according to the design of solar heat production. The hot water tank is placed near the return water pipe, and the pressure in the hot water tank adopts atmospheric pressure.

The solar collector receives sunlight radiation on the roof of the building to obtain heat. The temperature of the circulating water in the solar collector rises after heating and enters the heat exchanger. In the heat exchanger, the circulating water on the hot side is replaced by the return water on the cold side. After cooling, the cooled circulating water is pressurized by the circulating water pump and then enters the solar collector again.

The pumping water pump extracts the heating return water in the return water pipe and enters the cold side of the heat exchanger of the solar heating subsystem, and the return water is heated by high-temperature circulating water in the heat exchanger, and then enters the hot water tank; The water pump is placed downstream of the heat exchanger to prevent the pressure of the heat exchanger pipeline from being too high; a switch valve is placed upstream of the heat exchanger to shut off the valve when it stops working.

A temperature sensor is installed at the outlet of the solar collector. When the outlet water temperature of the solar collector is higher than the set temperature, the circulating water volume of the circulating water pump is increased under the control of the control device. When the outlet water temperature of the solar collector is lower than the set temperature temperature, under the control of the control device, reduce the circulating water volume of the circulating water pump; install a sensor at the cold side outlet of the heat exchanger, and when the return water temperature of the cold side outlet is higher than the set temperature, increase it under the control of the control device The circulating water volume of the water pump for pumping, when the temperature of the return water at the outlet of the cold side is lower than the set temperature, reduce the circulating water volume of the water pump for pumping under the control of the control device; when the solar heating subsystem stops working, under the control of the control device Close the valve on the pumping water pipeline.

An exhaust valve is installed on the top of the hot water tank, and an observation hole is arranged, and a temperature sensor, a water level sensor and a pressure sensor are installed in the hot water tank.

The hot water tank is connected with multiple pumping water pipes, and the return water in each pumping water pipe enters the hot water tank through the water pump; the water outlet of the hot water tank is connected with a booster water pump, and the booster water pump is connected to the heat pump The water tank and the water supply pipe pipeline, the pressurized water pump pumps the hot water in the hot water tank into the water supply pipe; each pumping water pipe pipeline is connected to the bottom of the hot water tank, and the outlet of the water supply pipe of the water tank is installed slightly higher than the bottom s position.

When the water temperature in the hot water tank reaches the set value and the water level of the water tank is higher than the warning water level, the booster water pump pumps the hot water in the water tank into the water supply pipe; when the water level in the hot water tank is lower than the warning water level, the booster pump The water pump stops working, and when the pressure in the hot water tank is greater than the set value, the exhaust valve is opened.

Description of drawings

Fig. 1 solar water heating system diagram;

Figure 2 Structural diagram of the hot water tank.

detailed description

Between the supply and return pipes of the district heating system is the area where the system is located. The solar water heating system proposed by the present invention completes the process of using solar energy to heat the return water and sending the high temperature return water into the water supply pipe.

Embodiment 1, as shown in Figure 1. In the system of this embodiment, there are 3 sets of solar heating subsystems, corresponding to 3 pumping pipelines. In addition, there is a shared hot water tank and a supply pump No. 7 Pump7.

The system places solar collectors on the roofs of three buildings. Preferably, the area of No. 1 solar collector is 100m ² ; the area of No. 2 solar collector is 200m ² ; the area of No. 3 solar collector is 500m ² .

Solar heat collector No. 1, circulating water pump No. 1 Pump1 and heat exchanger No. 1 form solar heating subsystem No. 1. Valve No. 1 Valve1, heat exchanger No. 1 and pump No. 2 Pump2 form the pumping pipeline No. 1.

Solar heat collector No. 2, circulating water pump No. 3 Pump3 and heat exchanger No. 2 form solar heating subsystem No. 2. Valve No. 2 Valve2, heat exchanger No. 2 and pump No. 4 Pump4 form the pumping pipeline No. 2.

Solar heat collector No. 3, circulating water pump No. 5 Pump5 and heat exchanger No. 3 form solar heating subsystem No. 3. Valve No. 3 Valve3, heat exchanger No. 3 and pump No. 6 Pump6 form the pumping pipeline No. 3.

Taking the joint working principle of solar heating subsystem No. 1 and pumping pipeline No. 1 as an example, the working principles of each subsystem in this embodiment are described. In solar collector No. 1, circulating water with lower temperature enters collector No. 1, and after being heated by sunlight radiation, circulating water with higher temperature leaves the collector. Temperature sensor No. 1 T1 monitors the circulating water temperature at the outlet of the collector. The circulating water enters the hot water side of heat exchanger No. 1 after leaving the collector. After heat exchange, the temperature of circulating water decreases. After the circulating water leaves the heat exchanger, it enters the circulating water pump No. 1 Pump1 for pressurization. The pressurized circulating water flows into the No. 1 solar collector. At temperature sensor No. 1 T1, if the water temperature at the collector outlet is lower than the set temperature (preferably 75-95°C), the circulating water volume is reduced by adjusting the operating frequency of circulating water pump No. 1 Pump1. If it is higher than the set temperature, increase the amount of circulating water.

A PID controller is preferred, which uses the T1 temperature value to adjust the circulating water volume.

In the No. 1 pumping pipeline, the return water (generally 30-50° C.) in the return pipe is pumped into the pipeline under the action of the No. 2 pump Pump2. The pumped water in the pumped water pipe passes through the cold water side of heat exchanger No. 1 to absorb the heat of circulating water. After the pumped water is heated, it is pressurized by No. 2 Pump 2 and then enters the hot water tank. Heat exchanger No. 1 is a water-water heat exchanger, preferably in a countercurrent arrangement.

The temperature sensor T1 monitors the pumped water temperature at the outlet of the No. 1 cold water side of the heat exchanger. At temperature sensor No. 2 T2, if the pumped water temperature at the outlet of the cold water side of heat exchanger No. 1 is lower than the set temperature (preferably 65-85°C), reduce the pumped water by adjusting the operating frequency of pump No. 2 Pump2 . If it is higher than the set temperature, increase the pumping volume.

A PID controller is preferred, which uses the second temperature value T2 to adjust the amount of pumped water.

When the solar heating subsystem No. 1 stops heating, close the valve No. 1 Valve1. Arrange the No. 1 pressure sensor P1 at the connection between the No. 1 pumping pipe and the return pipe. The function of P1 is to monitor the pressure value at the return pipe. When the pressure value of P1 is lower than the alarm value, valve No. 1 Valve1 is closed to prevent backflow of pumped water in No. 1 pumping pipeline.

The joint working principle of solar heating subsystem No. 2 and pumping pipeline No. 2, solar heating subsystem No. 3 and pumping pipeline No. 3 and the joint work of the above-mentioned solar heating subsystem No. 1 and pumping pipeline No. 1 The principle is the same.

When ignoring heat loss, according to the law of energy conservation, the heat provided by the solar collector to the circulating water is equal to the heat obtained by pumping water. Then the formula is:

Heat _s = M ¹ C _p ¹ (T _f ¹ -T _r ¹ ) = M ² C _p ² (T _f ² -T _r ² )(1)

Among them, M ¹ is the circulating water flow rate of the solar heating subsystem No. 1, the unit is kg/s; C _p ¹ is the average specific heat capacity of the circulating water of the solar heating subsystem No. 1, the unit is J/kg; T _f ¹ T r 1 is the water temperature at the collector No. 1 outlet of the circulating water of the solar heating subsystem No. 1, in degrees Celsius; T _r ¹ is the inlet water temperature of the collector of the circulating water of the solar heating subsystem No. 1, in °C; M ² is the pumping flow rate of No. 1 pumping pipeline, the unit is kg/s; C _p ² is the average pumping specific heat capacity of No. 1 pumping pipeline, and the unit is J/kg; T _f ² is the outlet water temperature of No. 1 pumping pipeline , the unit is ℃; T _r ² is the inlet water temperature of the pumping pipeline No. 1, the unit is ℃; Heat _s is the heat from the solar collector No. 1, the unit is watts w.

If the solar radiation absorbed by solar collector No. 1 is 800W/m2, the solar energy obtained by solar collector No. 1 is 8kW. When the following parameters are taken, C _p ¹ =4200J/kg, T _f ¹ =40°C, T _r ¹ =40°C, C _p ² =4200J/kg, T _f ² =40°C, T _r ² =40°C. From the formula (1), it can be seen that the circulating water flow M ¹ of the solar collector No. 1 and the pumping flow M ² of the pumping pipeline No. 1 are respectively, M ¹ =0.0381kg/s; M ² =0.0346kg/s; similar , it can be obtained that the circulating water flow M ³ of the solar collector No. 2 and the pumping flow M ⁴ of the pumping pipeline No. 2 are respectively, M ³ =0.0762kg/s; M ⁴ =0.0693kg/s; The circulating water flow rate M5 of collector No. 3 and the pumping water flow rate M6 of pumping pipeline No. ^{3 are respectively, M 5 =} 0.190kg/s ^{; M 6 =} 0.0173kg/s;

In engineering application, the set temperature at the outlet of each pumping pipeline is preferably the same temperature value. Otherwise, each water pumping pipeline will mix pumped water at different temperatures in the hot water tank, which will easily cause uneven water temperature in the water tank. This uneven phenomenon is not conducive to stable heat supply.

The hot water tank is wrapped with an outer insulation layer to isolate the heat from the hot water and the external environment. Each pump for pumping water and its water pipes are connected to the bottom of the hot water tank. The outlet of the water supply pipe of the hot water tank is installed at a position slightly higher than the bottom. The water supply pipe of the hot water tank is connected to a No. 7 booster pump Pump7. The booster pump is connected to the hot water tank and the water supply pipeline. The booster pump pumps hot water from the hot water tank into the water supply pipe. The shape of the hot water tank can be cube or cylinder etc. Open the observation hole on the top of the water tank. The large water tank has a manhole. A temperature sensor, a water level sensor and a pressure sensor are installed in the hot water tank. When the water temperature in the hot water tank reaches the set value and the water level of the water tank is higher than the warning water level, No. 7 Pump7 of the booster pump pumps the hot water in the water tank into the water supply pipe. When the water level in the hot water tank was lower than the warning water level (preferably 10% of the full water level in the casing), No. 7 Pump7 of the booster pump stopped working. When the pressure sensor in the hot water tank detects that the pressure in the tank is greater than the set value, the exhaust valve is opened to reduce the pressure in the tank. The pressure setting value is preferably a gauge pressure of 5Kpa.

Claims (10)

1. a kind of novel solar water heating system, it is characterised in that the system includes：Control device, one or more sun Can heat supply subsystem, boiler, water pump and water pipe；

Solar-heating subsystem includes solar-heating subsystem and solar energy cold water side sub-system；

Solar-heating subsystem includes solar thermal collector, cycling use of water pump, temperature sensor and water pipe；

Solar energy cold water side sub-system includes drawing water with water pump, temperature sensor, heat exchanger, valve, pressure sensor and water pipe；

Control device and solar thermal collector, heat exchanger, boiler, valve, water pump, temperature sensor and pressure sensor communication Connect to be controlled；

Solar-heating subsystem is acted between water supply used water pipe and backwater water pipe.

2. a kind of novel solar water heating system according to claim 1, it is characterized in that when thering is multiple to build in heat supply region When building, a solar-heating subsystem is arranged in each building roof.

3. a kind of novel solar water heating system according to claim 1, it is characterized in that the solar water heating system is located at In the secondary heat supply network of district heating, the solar water heating system extracts the relatively low heat supply of temperature from the backwater conduit pipeline of heat supply network Backwater, by after heating, then temperature hot water higher is added in the water supply used water pipeline of heat supply network.

4. a kind of novel solar water heating system according to claim 1, it is characterized in that multiple solar-heating subsystems A boiler is shared, the boiler is covered using insulation material, capacity is designed according to solar energy quantity of heat production and determined, the boiler It is placed near water return pipeline, the pressure in boiler uses atmospheric pressure.

5. a kind of novel solar water heating system according to claim 1, it is characterized in that solar thermal collector is in building Apical grafting is obtained heat by solar irradiation, and the recirculated water in solar thermal collector is raised by temperature after heating, into heat exchanger, In heat exchanger, the recirculated water of hot side is cooled down by the backwater of cold side, and the recirculated water after cooling enters again after being pressurized by cycling use of water pump Enter solar thermal collector.

6. a kind of novel solar water heating system according to claim 1, uses it is characterized in that drawing water and extracting backwater with water pump Heat supply backwater in water pipe enters the heat exchanger cold side of solar-heating subsystem, and backwater is added in heat exchanger by high temperature circulation water Heat, subsequently into boiler；Wherein, to draw water and be placed on heat exchanger downstream with water pump, prevent heat exchanger tube hypertonia；Heat exchange One controlled valve of device placed upstream, the Shuttoff Valve when being stopped.

7. a kind of novel solar water heating system according to claim 1, it is characterized in that in the outlet of solar thermal collector Mounting temperature sensor, when solar thermal collector exit water temperature is more than design temperature, increases follow under control of the control means The quantity of circulating water of ring water pump, when solar thermal collector heat collector exit water temperature is less than design temperature, in the control of control device The lower quantity of circulating water for reducing cycling use of water pump；

In the cold side outlet port install sensor of heat exchanger, when the return water temperature of cold side outlet port is more than design temperature, filled in control Increase the quantity of circulating water drawn water with water pump under the control put, when the return water temperature of cold side outlet port is less than design temperature, in control The quantity of circulating water drawn water with water pump is reduced under the control of device；

When solar-heating subsystem is stopped, closes draw water with the valve on water pipe line under control of the control means Door.

8. a kind of novel solar water heating system according to claim 1, it is characterized in that hot water tank top installs exhaust steam valve, Peep hole, mounting temperature sensor, level sensor and pressure sensor in boiler are set.

9. a kind of novel solar water heating system according to claim 1, the use it is characterized in that boiler connection multiple is drawn water Draw water and boiler is entered by suction pump with the backwater in water pipe line in water pipe line, each road；The delivery port connection one of boiler Supercharging water pump, supercharging connects boiler and water supply used water pipe pipeline with water pump, and supercharging water pump is by the heat-exchanger pump in boiler Enter water supply used water pipe；Respectively to draw water and connect boiler bottom with water pipe line, the outlet of cistern water supply water pipe is arranged on the bottom of apart from The slightly higher position in portion.

10. a kind of novel solar water heating system according to claim 1, its feature；When the water temperature in boiler reaches When setting value and cistern water level are higher than early warning water level, the hot water in water tank is pumped into water supply used water pipe by supercharging water pump, works as hot water When water level is less than early warning water level in case, supercharging is stopped with water pump, when pressure is more than setting value in boiler, opens steam discharge Valve.