A waterless solar clean energy supply system for remote areas

Abstract

The present invention relates to the field of solar power supply technology, and more specifically, to a waterless solar clean energy supply system for use in remote areas. The system comprises a photovoltaic array 1, a programmable logic controller (PLC) system controller 5, and a heating terminal 8 with a heat storage function. The photovoltaic array 1 converts light energy into direct current (DC) electricity, which is used to supply power to the heating terminal 8 with a heat storage function. The heating terminal 8 with a heat storage function converts the electricity provided by the photovoltaic array 1 into heat storage capacity, which is then stored. The PLC system controller 5 determines whether to input the DC power output by the photovoltaic array 1 into the heating terminal 8 with a heat storage function based on solar radiation intensity, and determines whether to disconnect the DC power output by the photovoltaic array 1 to the heating terminal 8 with a heat storage function based on the amount of heat stored in the heating terminal 8. This achieves precise control of the energy supply to the heating terminal.

Description

Technical Field

[0001] The present invention relates to the technical field of solar power supply, and in particular to a waterless solar clean energy supply system for remote areas. Background Art

[0002] In solar-rich regions like the Qinghai-Tibet Plateau, solar energy is becoming the primary clean heating energy source. Traditional solar energy utilization primarily relies on solar thermal energy, with water as the primary heat transfer medium. However, using water as a heat transfer medium carries risks such as water freezing, blocked transmission channels, and overheated water causing pipe bursts. Furthermore, the maintenance workload is high, making this type of heating system unsuitable for buildings in remote areas, such as dispersed agricultural and pastoral areas. Furthermore, to achieve carbon neutrality in remote buildings, the energy supply system must not only address heating needs but also address multiple energy needs, such as domestic hot water and lighting. Traditional solar heating systems only address heating needs and cannot meet these diverse energy needs.

[0003] Traditional photovoltaic power generation systems primarily rely on energy storage, which is costly and uneconomical. For heating applications, photovoltaic grid-connected systems are often used, employing either a photovoltaic-first or energy storage-first control strategy. The entire system is set to power the heating terminal, prioritizing photovoltaic power generation. When photovoltaic power generation is insufficient, batteries or the mains are used to supply the terminal load, failing to minimize mains power consumption. Given the poor economics of remote areas, a new energy supply system and control method designed to minimize mains power consumption is urgently needed. Summary of the Invention

[0004] In response to the problems raised in the background technology, the present invention converts solar energy into thermal energy storage instead of using water as a heat transfer medium. It also changes the traditional photovoltaic priority or electricity storage priority control strategy, and takes the maximization of photovoltaic electricity storage at the heating terminal as the control principle, and changes the power to supply energy to the heating terminal, thereby maximizing the reduction of city electricity consumption and proposing a waterless solar clean energy supply system for remote areas.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A waterless solar clean energy supply system for remote areas, comprising a photovoltaic array (1), a PLC system controller (5), a heating terminal (8) with a heat storage function, and a current and voltage detection device (7);

[0007] The photovoltaic array (1) is used to convert light energy into direct current electrical energy, and output the direct current electrical energy to the heating terminal (8) with a heat storage function, so as to provide electrical energy to the heating terminal (8) with a heat storage function;

[0008] The heating terminal (8) with heat storage function is used to convert the electric energy provided by the photovoltaic array (1) into heat storage, store the heat storage, and return it to indoor heating;

[0009] The PLC system controller (5) determines whether to input the DC power output by the photovoltaic array (1) into the heating terminal (8) with a heat storage function according to the intensity of solar radiation, and determines whether to disconnect the DC power output by the photovoltaic array (1) to the heating terminal (8) with a heat storage function according to the amount of heat stored in the energy supplied by the heating terminal (8) with a heat storage function;

[0010] When T xb >T xbs When T , it means that the phase change material in the energy supply of the heating terminal (8) with heat storage function has completely changed phase, the heat storage has reached 100%, and no more heat storage is carried out; otherwise, heat storage continues to be carried out in the heating terminal (8) with heat storage function until T xb >T xbs , T xbs is the temperature after the phase change material completely changes phase, T xb is the phase change point temperature of the phase change material in the heating terminal (8) with heat storage function;

[0011] The current and voltage detection device (7) is used to monitor the current value and voltage value of the input end of the heating terminal (8) with heat storage function;

[0012] The heating terminal (8) with heat storage function comprises a phase change material, and the amount of heat stored in the heating terminal (8) with heat storage function is determined by the temperature T of the phase change material at time i. i To characterize:

[0013]

[0014] Q X U is the heat storage capacity of the heating terminal (8) with heat storage function; i7 is the voltage at time i detected by the current and voltage detection device (7), I i7 is the current at time i detected by the current and voltage detection device (7); h is the indoor convection heat transfer coefficient; T x(t) is the surface temperature of the heating terminal (8) with heat storage function at time t, T n(t) is the indoor temperature at time t; i is the current supply time of the heating terminal (8) with heat storage function; A is the heat exchange area of the heating terminal (8) with heat storage function; m is the weight of the phase change material of the heating terminal (8) with heat storage function; h jx It is the phase change enthalpy value of the phase change material of the heating terminal (8) with heat storage function.

[0015] The above scheme determines whether to input the DC power output by the photovoltaic array (1) into the heating terminal (8) with a heat storage function according to the intensity of solar radiation, and determines whether to disconnect the DC power output by the photovoltaic array (1) to the heating terminal 8 with a heat storage function according to the amount of heat stored in the energy supplied by the heating terminal (8) with a heat storage function, thereby achieving precise control of the energy supply to the heating terminal, changing the strategy of constant input power to the heating terminal, and reducing the loss of mains electricity.

[0016] As a preferred embodiment of the present invention, the PLC system controller (5) determines whether to input the DC power output by the photovoltaic array (1) into the heating terminal (8) with heat storage function according to the solar radiation intensity, specifically including:

[0017] Set the horizontal solar radiation threshold TH s , judge the horizontal solar radiation value and the horizontal solar radiation threshold TH s When the horizontal solar radiation is less than the horizontal solar radiation threshold TH s , disconnecting the DC power outputted by the photovoltaic array (1) to the heating terminal (8) with heat storage function; when the horizontal solar radiation is greater than the horizontal solar radiation threshold TH s , connect the photovoltaic array (1) to output direct current power to the heating terminal (8) with heat storage function.

[0018] As a preferred solution of the present invention, it also includes a DC voltage regulator (6),

[0019] The DC voltage regulator (6) is electrically connected between the output end of the photovoltaic array (1) and the input end of the heating terminal (8) with heat storage function, and is used to adjust the input voltage of the heating terminal (8) with heat storage function according to the output voltage of the photovoltaic array (1), so that the following equation is established:

[0020]

[0021] Among them, U i4 is the output voltage value of the photovoltaic array (1) at time i, I i4 is the current value of the photovoltaic array (1) detected at time i, R 供暖 It is the total resistance of the electricity-to-heat equipment in the heating terminal (8) with heat storage function.

[0022] The function of the DC voltage regulator (6) is to ensure that the output power of the photovoltaic array (1) is equal to the input power of the heating terminal (8) with heat storage function through voltage regulation. When the output power of the photovoltaic array (1) is greater than the input rated power of the heating terminal (8) with heat storage function, the DC voltage regulator (6) is used to limit the input voltage of the heating terminal (8) with heat storage function. The excess power generated by the photovoltaic array (1) is consumed by other loads or stored in the battery, ensuring that the power consumption demand of the heating terminal (8) with heat storage function is met first.

[0023] As a preferred solution of the present invention, it further includes a first current and voltage detector (4);

[0024] The first current and voltage detector (4) is used to monitor the current value and voltage value of the DC power output by the photovoltaic array (1), and transmit the collected current value and voltage value of the DC power output by the photovoltaic array (1) to the PLC system controller (5);

[0025] The PLC system controller (5) is used to calculate the power of the photovoltaic array (1) based on the current value and voltage value of the DC electric energy output by the photovoltaic array (1), and is used to adjust the output voltage of the heating terminal (8) with heat storage function based on the output voltage of the photovoltaic array (1), so that the output voltage value of the DC voltage regulator (6) is within the range of ±5% of the calculated theoretical output voltage value.

[0026] As a preferred embodiment of the present invention, the heating terminal (8) with heat storage function includes an electric heating film or heating cable that can receive AC or DC power, a device that converts electrical energy into thermal energy, and a material that can store heat.

[0027] As a preferred solution of the present invention, it also includes a photovoltaic controller (11), an inverter (12) and an AC distribution cabinet (15);

[0028] The photovoltaic controller (11) is used to output the excess electric energy generated by the photovoltaic array (1) to the inverter (12);

[0029] The inverter (12) is used to convert the excess electric energy generated by the photovoltaic array (1) from direct current into alternating current, and output the alternating current to the AC distribution cabinet (15);

[0030] The AC power distribution cabinet (15) is used to output the input AC power to the terminal AC load.

[0031] Through the photovoltaic controller (11), inverter (12) and AC distribution cabinet (15), the photovoltaic array (1) not only stores heat for the heating terminal (8) with heat storage function, but also converts electrical energy from direct current into alternating current and outputs it to the terminal AC load to provide electricity for other living needs besides heating.

[0032] As a preferred solution of the present invention, the terminal AC load includes a lighting load (16), a domestic hot water load (17) and other loads (15).

[0033] As a preferred embodiment of the present invention, the PLC system controller (5) aims to minimize the power consumption of the mains bus network by the sum of the power consumed by the heating terminal (8) with heat storage function and the terminal AC load, and the goal is achieved by:

[0034] It also includes a third switch K3, which is connected to the PLC system controller (5) and the mains power grid bus and is used to open or close according to the control instruction of the PLC system controller (5).

[0035] When the indoor temperature T n Greater than the minimum acceptable indoor temperature T ns1 When the third switch K3 is disconnected, the electrical connection between the grid bus and the input end of the heating terminal (8) with heat storage function is disconnected; when the indoor temperature T n Lower than the minimum acceptable indoor temperature T ns1 When the third switch K3 is closed, the grid bus is connected to the input end of the heating terminal (8) with heat storage function.

[0036] By indoor temperature T n and the minimum acceptable indoor temperature T ns1 By comparing the power supply and the heating terminal (8) with heat storage function, it is determined whether the mains power is connected to the system, and the strategy of constant input power is no longer adopted, thereby reducing the consumption of mains power.

[0037] As a preferred embodiment of the present invention, a storage battery (18) is further included. The storage battery (18) is connected to the photovoltaic controller (11) and is used to store excess electric energy generated by the photovoltaic array (1) or output the stored electric energy to the system through the inverter (12) to supply power to the terminal AC load.

[0038] As a preferred embodiment of the present invention, the present invention further includes a fifth switch K5, which is a double-cut switch. One end of the fifth switch K5 is connected to the PLC system controller (5), and the other end of the fifth switch K5 is connected to the output end of the inverter (12) or the output end of the grid bus. When the other end of the fifth switch K5 is connected to the output end of the inverter (12), the working power supply of the PLC system controller (5) is supplied by the photovoltaic array (1) or the battery (18). When the other end of the fifth switch K5 is connected to the output end of the grid bus, the working power supply of the PLC system controller (5) is supplied by the mains power grid.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The system and method of the present invention use solar power generation to provide energy, and the terminal energy storage is transformed from traditional electricity storage to heat storage, which improves the economy of the system while solving multiple energy needs of heating, lighting and domestic hot water. In terms of control mode, the traditional photovoltaic priority or electricity storage priority control strategy is changed, and the control principle is to maximize the storage of photovoltaic electricity at the heating terminal, thereby minimizing the consumption of city electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of a waterless solar clean energy supply system for remote areas in Example 1;

[0042] Figure 2 This is a control logic diagram of a control method for a waterless solar clean energy supply system suitable for remote areas in Example 2;

[0043] Figure 3 This is a comparison chart of the photovoltaic heating time of a waterless solar clean energy supply system suitable for remote areas and its control method using the present invention in Example 2 and the photovoltaic heating time of a traditional system. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, this should not be understood as limiting the scope of the present invention to the following embodiments, and all technologies implemented based on the present invention fall within the scope of the present invention.

[0045] Example 1

[0046] A waterless solar clean energy supply system for remote areas, the principle diagram is as follows Figure 1 As shown, it includes a photovoltaic array 1, a first current and voltage detector 4, a PLC system controller 5, a DC voltage regulator 6 and a heating terminal 8 with a heat storage function.

[0047] The photovoltaic array 1 converts light energy into DC power and outputs the DC power to the DC voltage regulator 6; the DC voltage regulator 6 is used to adjust the power supply pressure according to the DC power, and output the regulated DC power to the heating terminal 8 with heat storage function, so that the output power of the photovoltaic array 1 is balanced and matched with the power of the heating terminal 8 with heat storage function; the first current and voltage detector 4 is used to monitor the current value and voltage value of the DC power output by the photovoltaic array 1, and transmit the collected current value and voltage value of the DC power output by the photovoltaic array 1 to the PLC system controller 5; the PLC system controller 5 is used to calculate the power of the photovoltaic array 1 according to the current value and voltage value of the DC power output by the photovoltaic array 1, and the PLC system controller 5 controls the output voltage of the DC voltage regulator 6 according to the power of the photovoltaic array 1.

[0048] The system further includes a current and voltage detection device 7, and the method in which the DC voltage regulator 6 adjusts the power supply pressure according to the DC power includes the following steps:

[0049] The current and voltage detection device 7 is used to collect the voltage and current values output by the DC voltage regulator 6, and the power output by the DC voltage regulator 6 to the heating terminal 8 with heat storage function is calculated; the power output by the photovoltaic array 1 is calculated based on the voltage and current values collected by the first current and voltage detector 4, and the power output by the DC voltage regulator 6 to the heating terminal 8 with heat storage function is compared with the power output by the photovoltaic array 7 to obtain the power difference, and the output voltage of the DC voltage regulator 6 is adjusted so that the power difference is within the preset power matching range to avoid overload protection of the system.

[0050] The heating terminal 8 with heat storage function includes an electric heating film or a heating cable that can receive AC or DC power, a device that converts electrical energy into thermal energy, and a material that can store heat.

[0051] The system further includes a third switch K3, which is connected to the input end of the heating terminal 8 with heat storage function and the output end of the grid bus. The third switch K3 is connected to the PLC system controller 5 and is used to open or close according to the control instruction of the PLC system controller 5. When the indoor temperature T n Greater than the minimum acceptable indoor temperature T ns1 When the third switch K3 is disconnected, the electrical connection between the grid bus and the input end of the heating terminal 8 with heat storage function is disconnected; when the indoor temperature T n Lower than the minimum acceptable indoor temperature T ns1When the third switch K3 is opened and closed, the grid bus is connected to the input end of the heating terminal 8 with heat storage function. After the DC voltage regulator 6 adjusts the voltage, the input end of the heating terminal 8 with heat storage function is no longer a fixed power match, but is controlled to open and close the third switch K3 based on the premise of minimizing the mains power consumption. During the day, the heating terminal 8 with heat storage function stores heat and slowly releases heat to the room for heating. At night, the heating terminal 8 with heat storage function releases the stored heat to the room to ensure the indoor temperature. When the heat stored in the heating terminal 8 with heat storage function is insufficient, the PLC system controller 5 determines that the third switch K3 can be closed, and the mains power is measured by the meter 9 to supplement the heating terminal (8) with heat storage function.

[0052] As a preferred solution, the system further includes a photovoltaic controller 11, an inverter 12 and an AC distribution cabinet 15;

[0053] The photovoltaic controller 11 is used to output the excess electric energy generated by the photovoltaic array 1 to the inverter 12;

[0054] The inverter 12 is used to convert the excess power generated by the photovoltaic array 1 from direct current to alternating current, and output the alternating current to the terminal AC loads, which include lighting loads 16, domestic hot water loads 17, and other loads 15.

[0055] As a preferred solution, a battery 18 is further included. The battery 18 is connected to the photovoltaic controller 11 and is used to store electricity or output the stored electricity to the inverter 12 .

[0056] Furthermore, it includes a fifth switch K5, which is a double-cut switch. One end of the fifth switch K5 is connected to the PLC system controller 5, and the other end of the fifth switch K5 is connected to the output end of the inverter 12 or the output end of the grid bus. When the other end of the fifth switch K5 is connected to the output end of the inverter 12, the working power supply of the PLC system controller 5 is supplied by the photovoltaic array 1 or the battery. When the other end of the fifth switch K5 is connected to the output end of the grid bus, the working power supply of the PLC system controller 5 is supplied by the mains power grid.

[0057] After constructing a waterless solar clean energy supply system for remote areas, a control method for the waterless solar clean energy supply system is also proposed.

[0058] The existing technology is a strategy of constant input power of the heating terminal 8 with heat storage function. The present invention does not adopt the strategy of constant input power of the heating terminal 8 with heat storage function. That is, when the power output of the photovoltaic array 1 is less than the input rated power of the heating terminal 8 with heat storage function, the mains power grid supplies power to the heating terminal 8 with heat storage function through the third switch K3, so that the mains power grid energy supply power plus the output power of the photovoltaic array 1 is equal to the input power of the heating terminal 8 with heat storage function, so that the input power of the heating terminal 8 with heat storage function is always constant. When the power output of the photovoltaic array 1 increases, the mains power grid energy supply power decreases; when the power output of the photovoltaic array 1 decreases, the mains power grid energy supply power increases. The disadvantage of the strategy of constant input power of the heating terminal 8 with heat storage function is that it actually ensures the indoor temperature T n If the temperature is greater than the minimum acceptable indoor temperature, T ns1 It can meet the heating needs of life. If the photovoltaic array can meet the minimum temperature of the heating, there is no need to supplement the mains electricity, so the access to the mains electricity can be reduced to save energy. The input power of the heating terminal 8 with heat storage function is constant and does not care about the indoor temperature, resulting in a waste of electricity (in fact, the indoor temperature may be very high, but the mains electricity is still being input).

[0059] The system control objective function is:

[0060]

[0061] is the mains electricity consumption measured by the electric meter 9 at time i, = is the utility power consumption measured by electricity meter 10 at time i. To minimize utility power consumption, the sum of the utility power consumption of the heating terminal 8 with heat storage, other loads 15, lighting loads 16, or domestic hot water 17 must be minimized. For distributed buildings in remote areas, heating energy demand is the highest, and converting electricity into heat storage is the most economical. Therefore, system control prioritizes heating and heating thermal storage energy consumption, followed by other loads 15, lighting loads 16, or domestic hot water 17.

[0062] In the solution of the present invention, the strategy of constant input power of the heating terminal 8 with heat storage function is abandoned, and the control strategy is specifically as follows:

[0063] Set the lowest acceptable indoor temperature to T ns1 ;

[0064] When the indoor temperature T n Greater than the minimum acceptable indoor temperature T ns1 When the mains is not needed for supplementation, the third switch K3 remains disconnected, the output power of the photovoltaic array 1 is equal to the input power of the heating terminal 8 with heat storage function, and the input power of the heating terminal 8 with heat storage function is less than or equal to its rated power; when the indoor temperature Tn Lower than the minimum acceptable indoor temperature T ns1 When the PLC system controller 5 controls the third switch K3 to be closed, the mains power grid power is added to the input end of the heating terminal 8 with heat storage function. The photovoltaic array 1 and the mains power grid simultaneously supply energy to the heating terminal 8 with heat storage function to increase the indoor temperature T n Raise to a temperature greater than or equal to the lowest acceptable indoor temperature T ns1 In addition, in a more extreme case, the first switch K1 can be controlled to be disconnected, and the third switch K3 can be kept closed, so that only the mains electricity is used to power the heating terminal 8 with the heat storage function.

[0065] Furthermore, by controlling the on and off of the first switch K1 , it is controlled whether the power output by the photovoltaic array 1 is output to the heating terminal 8 with a heat storage function.

[0066] Set the horizontal solar radiation threshold TH s First determine the horizontal solar radiation value and the horizontal solar radiation threshold TH s For example, when the sun just rises, the solar radiation gradually increases, and the power output by the photovoltaic array 1 gradually increases. The threshold is used to determine whether the power output by the photovoltaic array 1 can be output to the horizontal plane. When the horizontal solar radiation is less than the horizontal solar radiation threshold TH s , the PLC system controller 5 controls the first switch K1 to be disconnected, so that the electrical connection between the DC voltage regulator 6 and the heating terminal 8 with heat storage function is disconnected. At this time, the power output of the photovoltaic array 1 is low, and there is no need to output power to the heating terminal 8 with heat storage function (power can be output to the heating terminal 8 with heat storage function through other means, such as batteries or mains electricity); when the horizontal solar radiation is greater than the horizontal solar radiation threshold TH s , the PLC system controller 5 controls the first switch K1 to be closed, thereby connecting the electrical connection between the DC voltage regulator 6 and the heating terminal 8 with heat storage function, and the power output by the photovoltaic array 1 is output to the heating terminal 8 with heat storage function.

[0067] Furthermore, as the solar radiation increases during the day, the power output by the photovoltaic array 1 gradually increases. During the day, there are the following two situations:

[0068] The power output by the photovoltaic array 1 is less than the input rated power of the heating terminal 8 with heat storage function;

[0069] The power output by the photovoltaic array 1 is greater than or equal to the input rated power of the heating terminal 8 with heat storage function.

[0070] When the power output by the photovoltaic array 1 is less than the input rated power of the heating terminal 8 with heat storage function, at this time, the output voltage of the DC voltage regulator 6 is adjusted to be equal to the input voltage, and the output current of the DC voltage regulator 6 is adjusted to be equal to the input current, that is, the power output by the photovoltaic array 1 is equal to the input power of the heating terminal 8 with heat storage function.

[0071] The power output of the photovoltaic array 1 is greater than or equal to the rated input power of the heating terminal 8 with thermal storage function. At this point, the heating terminal 8 with thermal storage function has reached its rated output power and its input power cannot be increased further. Further increase will cause the heating terminal 8 with thermal storage function to malfunction. The DC voltage regulator 6 adjusts the output voltage to the rated input voltage of the heating terminal 8 with thermal storage function. In addition to the power output of the photovoltaic array 1 being output to the heating terminal 8 with thermal storage function, the remaining power is output to the inverter 12. The inverter 12 converts the excess power generated by the photovoltaic array 1 from DC to AC and outputs the AC power to the terminal AC loads, which include lighting load 16, domestic hot water load 17, and other loads 15. If the power output by the photovoltaic array 1 remains after supplying energy to the heating terminal 8 with heat storage function and the terminal AC load, under the control of the photovoltaic controller 11, the power output by the voltage photovoltaic array 1 is also output to the battery 18, and the battery 18 stores the remaining electric energy output by the photovoltaic array 1. The electric energy stored in the battery 18 can also be output to the inverter 12 to supplement the electric energy for the lighting load 16, the domestic hot water load 17 and other loads 15.

[0072] Furthermore, the temperature T after the phase change material in the heating terminal 8 with heat storage function is completely changed is set. xbs ;

[0073] If the temperature T of the phase change material that can store heat in the heating terminal 8 with heat storage function is xb Greater than the temperature T after the phase change material is completely phase-changed xbs , indicating that the phase change material in the heating terminal energy supply with heat storage function has completely changed phase, the heat storage has reached 100%, and no more heat storage is carried out. K1 is disconnected, K3 is disconnected, otherwise heat storage continues to be carried out to the heating terminal 8 with heat storage function until T xb >T xbs .

[0074] Example 2

[0075] See also Figure 1 The schematic diagram of a waterless solar clean energy supply system for remote areas is described in detail as follows:

[0076] Energy supply system description:

[0077] Buildings in remote areas of the plateau have multiple needs for electricity, heating, and domestic hot water. The energy side of the waterless solar clean energy supply system is provided by the photovoltaic array 1. During the day, the photovoltaic array 1 generates DC power, which is then combined and enters the DC combiner box 2 and DC distribution cabinet 3 for convergence. When the power of the energy supply system is relatively low, the DC combiner box 2 and DC distribution cabinet 3 may not be set up.

[0078] Before DC power is supplied to the end load, a current and voltage detection device 4 is set up to monitor the current and voltage of the DC power output by the photovoltaic array, so as to calculate the output power of the entire photovoltaic array. The collected current and voltage values are transmitted to the PLC system controller 5 through the signal line for control decision-making.

[0079] During the day, the DC power generated by photovoltaics passes through the current and voltage detection device 4 and is used for heating first. It enters the DC voltage regulator 6, which is used to adjust the supply voltage so that the output power of the photovoltaic array 1 is balanced with the power of the DC heating terminal 8 with heat storage function, avoiding imbalance in the output of the photovoltaic array 1.

[0080] After the voltage regulation, the DC power is collected by the current and voltage detection device 7 for current and voltage information, and then enters the DC heating terminal 8 with heat storage function. The heating terminal 8 with heat storage function is a key component of the entire heating and heat storage, usually including electric heating film, heating cable, etc. The heating terminal 8 with heat storage function can withstand AC or DC power, and is a device that can convert electrical energy into thermal energy. Inorganic phase change materials, organic phase change materials or other heavy heat storage materials are used to store heat. During the day, the DC heating terminal 8 with heat storage function stores heat and slowly releases heat to heat the indoor temperature. At night, the stored heat is released into the room to ensure the indoor temperature. When the heat is insufficient, it can be supplemented by the mains electricity measured by the electric meter 9 after being determined by the PLC system controller 5.

[0081] When the PLC system controller 5 determines that there is surplus electricity for heating, the excess electricity enters the photovoltaic controller 11 and is preferentially converted from DC to AC through the inverter 12, generally 220V. After being measured by the meter 13, the AC electricity enters the AC distribution cabinet 14 to supply power to other loads 15, lighting loads 16, and domestic hot water loads 17 respectively.

[0082] The method by which the PLC system controller 5 determines whether there is surplus heating power is: the heat storage amount is calculated using the calculation formula of the phase change material heat storage. When the heat storage amount reaches 100%, the power output by the photovoltaic array 1 is the remaining heating power.

[0083] The heat storage capacity of the heating terminal 8 with heat storage function can be measured by an indirect scheme, using the temperature T of the phase change material at time i as i To characterize:

[0084]

[0085] Q X The heat stored in the heating terminal 8 with heat storage function; U i7 is the voltage at time i detected by the current and voltage detection device 7, I i7 is the current at time i detected by the current and voltage detection device 7; h is the indoor convection heat transfer coefficient, which is usually 8.7W / (m 2 ·K); T x(t) is the surface temperature of the heating terminal 8 with heat storage function at time t, T n(t) is the indoor temperature at time t; i The current is the energy supply time of the heating terminal 8 with heat storage function; A is the heat exchange area of the heating terminal 8 with heat storage function; m is the weight of the phase change material of the heating terminal 8 with heat storage function, unit is kg; h jx It is the phase change enthalpy value of the phase change material of the heating terminal 8 with heat storage function, and the unit is kj / kg.

[0086] If the PLC system controller 5 determines that there is still power remaining (the lighting power and the power of other loads are designed to be constant, and the rated power of other loads such as lighting and domestic hot water can be calculated. The power output of the photovoltaic array 1 minus the heating power minus the power consumption of other loads still remains), the remaining power is stored in the battery 18, which also powers the other loads 15, lighting load 16, and domestic hot water load 17. If the stored power is insufficient, it is supplemented by mains electricity, which is measured by the electric meter 10 and then powers the other loads 15, lighting load 16, and domestic hot water load 17.

[0087] The above electricity meters do not have to be set up, and can be omitted when metering sub-items are not required.

[0088] A control logic diagram of a waterless solar clean energy supply system control method suitable for remote areas is shown in the following figure: Figure 2 As shown in the figure, the control logic diagram control method is described as follows:

[0089] f(e) is the total amount of mains electricity consumed by the entire energy supply system, in kWh; p(i) is the total power consumed by the entire energy supply system at different times, in kW; h is the time corresponding to different p(i) values of the entire energy supply system; T n is the indoor temperature, TH is the horizontal solar radiation, unit is W / m 2 TH s The solar irradiance setting value for the photovoltaic array to provide energy for the indoor space is usually 300W / m 2 ;T ns1 The lowest acceptable indoor temperature, usually set at 10°C; T ns2The limit temperature for stopping the mains heating is usually set at 14℃; xb is the phase change point temperature of the phase change material in the heating terminal 8 with heat storage function; T xbs The temperature at which the phase change material completely changes phase, usually set to T xb High 2 ~ 6 ℃; K1, K2, K3, K4 are circuit on-off switches.

[0090] The system control objective function is:

[0091]

[0092] is the mains electricity consumption measured by the electric meter 9 at time i, = is the utility power consumption measured by electricity meter 10 at time i. To minimize utility power consumption, the sum of the utility power consumption of the heating terminal 8 with heat storage, other loads 15, lighting loads 16, or domestic hot water 17 must be minimized. For distributed buildings in remote areas, heating energy demand is the highest, and converting electricity into heat storage is the most economical. Therefore, system control prioritizes heating and heating thermal storage energy consumption, followed by other loads 15, lighting loads 16, or domestic hot water 17.

[0093] On the one hand, whether to input the power output by the photovoltaic array into the heating terminal 8 with heat storage function is determined according to the intensity of solar radiation, and whether to disconnect the photovoltaic array's energy supply to the heating terminal 8 with heat storage function is determined according to the amount of heat stored in the energy supply of the heating terminal 8 with heat storage function.

[0094] First, determine the photovoltaic array energy supply conditions. When it is early morning or evening, TH<TH s When the solar irradiance is weak, the photovoltaic array does not provide energy for the room, and K1 is disconnected; when TH>TH s When K1 is turned on and K3 is turned off, the power provided by the photovoltaic array 1 is regulated to U by the DC voltage regulator 6. i6 The principle of voltage regulation is to make the following equation hold true, that is, the power output by the photovoltaic array 1 is equal to the output power of the DC voltage regulator 6 (that is, the input power of the heating terminal 8 with heat storage function). If it is not true, it is necessary to reduce or increase the output voltage of the DC voltage regulator 6 so that the output voltage value of the DC voltage regulator 6 is within the range of ±5% of the output voltage value of the photovoltaic array 1.

[0095]

[0096] In system design, the rated power of the heating terminal 8 with heat storage function is slightly greater than the maximum power of the photovoltaic array, where U i4 is the output voltage value of the photovoltaic array at time i detected by the current and voltage detection device 4, I i4is the photovoltaic array current detected at time i by the current and voltage detection device 4, R 供暖 is the total resistance of the electric heat conversion equipment in the heating terminal 8 with heat storage function, and the total resistance satisfies the following formula:

[0097]

[0098] R1~R n It is the resistance of a single branch of the parallel-connected heating terminal 8 with heat storage function.

[0099] The voltage-regulated electric energy is used to power the heating terminal 8 with heat storage function. The electric energy is converted into heat energy through the heating cable or electric heating film and other electric heat conversion equipment in the terminal, which stores heat for the phase change material in the terminal. The heat storage capacity of the heating terminal 8 with heat storage function can be measured indirectly by the temperature T of the phase change material at time i. i To characterize:

[0100]

[0101] Q X The heat storage capacity in the heating terminal 8 with heat storage function; U i7 is the voltage at time i detected by the current and voltage detection device 7, I i7 is the current at time i detected by the current and voltage detection device 7; h is the indoor convection heat transfer coefficient, which is usually 8.7W / (m 2 ·K); T x(t) is the surface temperature of the heating terminal 8 with heat storage function at time t, T n(t) is the indoor temperature at time t; i The current is the energy supply time of the heating terminal 8 with heat storage function; A is the heat exchange area of the heating terminal 8 with heat storage function; m is the weight of the phase change material of the heating terminal 8 with heat storage function, unit is kg; h jx It is the phase change enthalpy value of the phase change material of the heating terminal 8 with heat storage function, and the unit is kj / kg.

[0102] When T xb >T xbs When , it means that the phase change material in the heating terminal 8 with heat storage function has completely changed phase, the heat storage has reached 100%, and no more heat storage is carried out. K1 is disconnected, K3 is disconnected, otherwise it continues to store heat in the heating terminal 8 with heat storage function until T xb >T xbs ;

[0103] On the other hand, it is determined whether to introduce the mains electricity into the system and use the mains electricity to supplement the control. When the indoor temperature is higher than the minimum acceptable temperature, that is, T n >T ns1When T n <T ns1 When the indoor temperature is too low and needs to be supplemented by the mains, the control system will turn on K3 and turn off K1. During the mains supplement process, the indoor temperature starts to rise. When T n >T ns2 , K3 is disconnected. This control method can save the use of commercial electricity and leave heat storage space for the heating terminal 8 with heat storage function.

[0104] When the heat storage capacity of the heating terminal 8 with heat storage function has reached 100%, if the photovoltaic array has excess power, the PLC system controller 5 will continue to determine whether the terminal has functional requirements for other loads 15, lighting loads 16 or domestic hot water 17. If so, it will determine whether the power of the battery 18 is sufficient. If sufficient, K2 will be connected and K4 will be disconnected, and the power provided by the photovoltaic array will be used to supply energy to the load. If insufficient, K4 will be connected and K2 will be disconnected, and the photovoltaic array will store power in the battery 18, and the mains power will be used to supply power to other loads 15, lighting loads 16 or domestic hot water 17.

[0105] In addition, if the PLC system controller 5 continues to determine that there are no functional requirements of other loads 15, lighting loads 16 or domestic hot water 17 at the terminal, it will then determine whether the power of the battery 18 is sufficient. If it is sufficient, the photovoltaic array 1 will stop generating electricity. If not, the battery 18 will be charged.

[0106] The comparison chart of heating power consumption of a waterless solar clean energy supply system and its control method suitable for remote areas and conventional heating energy storage is as follows: Figure 3 As shown, with this system, the photovoltaic system changes power to power the heating terminals 8 with heat storage function to store heat. The stored heat is provided purely by photovoltaic power, without consuming any mains electricity. After the power is changed, the heating terminals 8 with heat storage function can be kept on for a longer time. If the traditional fixed power supply is used, the heating terminals 8 with heat storage function will quickly be fully charged.

[0107] Finally, it should be noted that the embodiments described in detail above are only the best practices of the invention and cannot be used to limit the scope of rights of the invention. Equivalent replacement of the technical solutions recorded in the aforementioned embodiments does not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the invention, and they should all be included in the scope of the claims and description of the invention.

Claims

1. A waterless solar clean energy supply system for remote areas, characterized by: It includes a photovoltaic array (1), a PLC system controller (5), a heating terminal with a heat storage function (8), and a current and voltage detection device (7); The photovoltaic array (1) converts light energy into direct current electrical energy, and outputs the direct current electrical energy to the heating terminal (8) with a heat storage function, so as to provide electrical energy to the heating terminal (8) with a heat storage function; The heating terminal (8) with heat storage function is used to convert the electric energy provided by the photovoltaic array (1) into heat storage, store the heat storage, and return it to indoor heating; The PLC system controller (5) determines whether to input the DC power output by the photovoltaic array (1) into the heating terminal (8) with a heat storage function according to the solar radiation intensity, and determines whether to disconnect the DC power output by the photovoltaic array (1) to the heating terminal 8 with a heat storage function according to the amount of heat stored in the energy supplied by the heating terminal (8) with a heat storage function; When T xb >T xbs When T , it means that the phase change material in the energy supply of the heating terminal (8) with heat storage function has completely changed phase, the heat storage has reached 100%, and no more heat storage is carried out; otherwise, heat storage continues to be carried out in the heating terminal (8) with heat storage function until T xb >T xbs , T xbs is the temperature after the phase change material completely changes phase, T xb is the phase change point temperature of the phase change material in the heating terminal (8) with heat storage function; The current and voltage detection device (7) is used to monitor the current value and voltage value of the input end of the heating terminal (8) with heat storage function; The heating terminal (8) with heat storage function comprises a phase change material, and the amount of heat stored in the heating terminal (8) with heat storage function is determined by the temperature T of the phase change material at time i. i To characterize: ； Q X is the heat storage capacity of the heating terminal (8) with heat storage function; U i7 is the voltage at time i detected by the current and voltage detection device (7), I i7 is the current at time i detected by the current and voltage detection device (7); h is the indoor convection heat transfer coefficient; T x(t) is the surface temperature of the heating terminal (8) with heat storage function at time t, T n(t) is the indoor temperature at time t; i is the time for the electric current to supply energy to the heating terminal (8) with heat storage function; A is the heat exchange area of the heating terminal (8) with heat storage function; m is the weight of the phase change material of the heating terminal (8) with heat storage function; h jx is the phase change enthalpy value of the phase change material of the heating terminal (8) with heat storage function.

2. The waterless solar clean energy supply system for remote areas according to claim 1, characterized in that: The PLC system controller (5) determines whether to input the DC power output by the photovoltaic array (1) into the heating terminal (8) with heat storage function according to the solar radiation intensity, specifically including: Set the horizontal solar radiation threshold TH s , judge the horizontal solar radiation value and the horizontal solar radiation threshold TH s When the horizontal solar radiation is less than the horizontal solar radiation threshold TH s , disconnect the DC power outputted by the photovoltaic array (1) to the heating terminal (8) with heat storage function; when the horizontal solar radiation is greater than the horizontal solar radiation threshold TH s , connect the photovoltaic array (1) to output direct current power to the heating terminal (8) with heat storage function.

3. The waterless solar clean energy supply system for remote areas according to claim 1, characterized in that: Also includes a DC voltage regulator (6), The DC voltage regulator (6) is electrically connected between the output end of the photovoltaic array (1) and the input end of the heating terminal (8) with heat storage function, and is used to adjust the input voltage of the heating terminal (8) with heat storage function according to the output voltage of the photovoltaic array (1), so that the following equation is established: Among them, U i4 is the output voltage value of the photovoltaic array (1) at time i, I i4 is the current value of the photovoltaic array (1) detected at time i, It is the total resistance of the electricity-to-heat equipment in the heating terminal (8) with heat storage function.

4. The waterless solar clean energy supply system for remote areas according to claim 1, characterized in that: Also includes a first current and voltage detector (4); The first current and voltage detector (4) is used to monitor the current value and voltage value of the DC power output by the photovoltaic array (1), and transmit the collected current value and voltage value of the DC power output by the photovoltaic array (1) to the PLC system controller (5); The PLC system controller (5) is used to calculate the power of the photovoltaic array (1) based on the current value and voltage value of the DC power output by the photovoltaic array (1), and is used to adjust the output voltage of the heating terminal (8) with heat storage function based on the output voltage of the photovoltaic array (1), so that the output voltage value of the DC voltage regulator (6) is within the range of ±5% of the calculated theoretical output voltage value.

5. The waterless solar clean energy supply system for remote areas according to claim 1, characterized in that: The heating terminal (8) with heat storage function includes an electric heating film or a heating cable that can receive AC or DC power, a device that converts electrical energy into thermal energy, and a material that can store heat.

6. A waterless solar clean energy supply system for remote areas according to any one of claims 1 to 5, characterized in that: It also includes a photovoltaic controller (11), an inverter (12) and an AC distribution cabinet (15); The photovoltaic controller (11) is used to output excess electric energy generated by the photovoltaic array (1) to the inverter (12); The inverter (12) is used to convert the excess electric energy generated by the photovoltaic array (1) from direct current to alternating current, and output the alternating current to the AC distribution cabinet (15); The AC power distribution cabinet (15) is used to output the input AC power to the terminal AC load.

7. The waterless solar clean energy supply system for remote areas according to claim 6, characterized in that: The terminal AC loads include lighting loads (16), domestic hot water loads (17) and other loads (15).

8. The waterless solar clean energy supply system for remote areas according to claim 6, characterized in that: The PLC system controller (5) aims to minimize the power consumption of the mains bus network by the sum of the power consumed by the heating terminal (8) with heat storage function and the terminal AC load, and the goal is achieved by: It also includes a third switch K3, the third switch K3 is connected to the PLC system controller (5) and the mains power grid bus, and is used to open or close according to the control instruction of the PLC system controller (5). When the indoor temperature T n Greater than the minimum acceptable indoor temperature T ns1 When the third switch K3 is disconnected, the electrical connection between the grid bus and the input end of the heating terminal (8) with heat storage function is disconnected; when the indoor temperature T n Lower than the minimum acceptable indoor temperature T ns1 When the third switch K3 is closed, the grid bus is connected to the input end of the heating terminal (8) with heat storage function.

9. The waterless solar clean energy supply system for remote areas according to claim 6, characterized in that: It also includes a storage battery (18), which is connected to the photovoltaic controller (11) and is used to store excess electric energy generated by the photovoltaic array (1) or output the stored electric energy to the system through the inverter (12) to supply power to the terminal AC load.

10. The waterless solar clean energy supply system for remote areas according to claim 9, characterized in that: The system further comprises a fifth switch K5, which is a double-cut switch. One end of the fifth switch K5 is connected to the PLC system controller (5), and the other end of the fifth switch K5 is connected to the output end of the inverter (12) or the output end of the grid bus. When the other end of the fifth switch K5 is connected to the output end of the inverter (12), the working power supply of the PLC system controller (5) is supplied by the photovoltaic array (1) or the battery (18). When the other end of the fifth switch K5 is connected to the output end of the grid bus, the working power supply of the PLC system controller (5) is supplied by the mains power grid.

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