Factory aquaculture tropical fish direct drive type photovoltaic electricity-heat phase change heat storage zero-carbon heat supply system

Abstract

The invention discloses a tropical fish direct-drive type photovoltaic electricity-heat phase change heat storage zero-carbon heat supply system for factory aquaculture, and belongs to the field of modern facility fishery green production and the field of renewable energy source application. An electric heating film is arranged between the first shape-stabilized phase-change wallboard and the second shape-stabilized phase-change wallboard, and the first shape-stabilized phase-change wallboard serves as an inner side layer of the outer surface of the fishpond wall; an electric heating film is arranged in the wall body to serve as a middle layer of the outer surface of the fishpond wall, and a heat preservation layer arranged outside the second shape-stabilized phase change wall plate serves as an outer side layer of the outer surface of the fishpond wall; the first shape-stabilized phase-change wallboard, the second shape-stabilized phase-change wallboard, the electrothermal film and the thermal insulation layer form an electrothermal film-phase-change thermal storage wall subsystem; a photovoltaic assembly, a series of relays, a temperature collector and a temperature sensor form a photovoltaic electricity-heat subsystem. In the daytime, unstable low-voltage direct-current'garbage 'electricity generated by the photovoltaic module is absorbed and stored in real time, and meanwhile the rate of releasing heat to the fishpond is controlled through the'heat switch' according to the temperature difference between the phase change temperature of the electricity and the water temperature of the fishpond.

Description

Technical Field

[0001] The invention relates to a photovoltaic electricity self-generation and self-consumption factory aquaculture tropical fish direct-drive photovoltaic electric-thermal phase change heat storage and heating technology, belonging to the field of modern facility fishery green production and renewable energy application. Background Art

[0002] The application of photovoltaic / electrothermal technology, phase change thermal storage technology, and green building technology to the construction and production operations of factory-scale aquaculture fish ponds has important social and economic significance for applying renewable energy technology to facility fishery production, significantly improving my country's factory-scale aquaculture of tropical fish, low-carbon and high-efficiency production over the winter, and promoting rural revitalization and the development of modern facility fisheries.

[0003] For tropical fish farms, the water temperature in the fish ponds usually needs to be maintained above 25°C. Affected by winter outdoor climate conditions, most areas of my country, including the southern region, need to heat the fish pond water. Limited by coal-fired pollution, using fuel oil / gas / electric boilers to heat the fish pond water in winter is currently a common heating method. However, the challenges are high heating costs and low economic benefits.

[0004] Therefore, in order to solve the problem that the water temperature of the fish pond needs to be heated for the wintering production of tropical fish in factory-based aquaculture in most parts of my country, including the southern region, and the fossil energy heating cost is high and the economic benefit is low, the present invention proposes a direct-drive photovoltaic electric-thermal phase change thermal storage heating technology suitable for zero-carbon heating in winter for tropical fish in factory-based aquaculture. That is, the photovoltaic module technology, electric heating film technology, phase change thermal storage technology and building wall construction technology are organically integrated to form a photovoltaic module-electric heating film system and an electric heating film-phase change thermal storage fish pond system. The two systems are coupled to each other to achieve a "seamless" conversion of electric energy to thermal energy. In the heating season, the photovoltaic module-electric heating film system is used to convert the low-voltage DC power generated by the photovoltaic module system into thermal energy; then the electric heating film-phase change thermal storage wall system is used to store the thermal energy converted by the electric heating film in real time in the phase change thermal storage wall in close contact with it. When the water temperature of the fish pond drops, the phase change thermal storage wall transfers the stored heat to the fish pond water through the fish pond wall in close contact with it in a heat conduction manner, achieving the purpose of flexible heating of the fish pond by photovoltaic power. In other non-heating seasons, the electricity generated by photovoltaic modules is preferentially used to power DC power equipment such as ventilation and ventilating machines in aquaculture workshops, LED fish pond fill lights, fish pond water regeneration devices, fish pond oxygen preparation machines, air source heat pumps, etc., to achieve green electricity production in factory-scale aquaculture processes. Summary of the invention

[0005] The purpose of the present invention is to propose a photovoltaic power self-generation and self-consumption factory aquaculture tropical fish direct-drive photovoltaic electric-thermal phase change heat storage zero-carbon heating system ( Figure 1 ) to realize green electricity production in factory-scale aquaculture technology.

[0006] The present invention mainly includes a first shaped phase change wallboard and a second shaped phase change wallboard, an electric heating film 2 adjacent to the first shaped phase change wallboard and the second shaped phase change wallboard, a thermal insulation layer 3, a photovoltaic module 4 and a DC power device 5, and also includes a series of relays 6, a temperature collector 7, and a temperature sensor 8. It is characterized in that the first shaped phase change wallboard and the second shaped phase change wallboard have built-in electric heating film 2 (middle layer on the outer surface of the fish pond wall) and a thermal insulation layer 3 (outer layer on the outer surface of the fish pond wall) to form an electric heating film-phase change thermal storage wall subsystem ( Figure 2 ); photovoltaic module 4, electric heating film 2, a series of relays 6, temperature collector 7, temperature sensor 8 constitute photovoltaic electric-thermal subsystem ( Figure 3 ); The two subsystems are organically combined into a direct-drive photovoltaic electric-thermal phase change thermal storage zero-carbon heating system. The electric heating film 2 is a common part of the two subsystems.

[0007] The first shaped phase change wallboard and the second shaped phase change wallboard can be formed by directly applying a cement composite shaped phase change material mortar on the surface of the building wall, or casting it into a prefabricated board and then pasting it on the surface of the building wall, so as to improve the heat storage capacity of the enclosure structure; wherein, the cement composite shaped phase change material mortar (see ZL201010210819.2 for details) is a cement-based composite shaped phase change material plastering (or cast-in-place) mortar made by mixing the shaped phase change material with the cement material, and the cement-based composite shaped phase change material is placed on the surface of the building enclosure, such as the wall, the ground, etc. through the plastering process or the prefabricated board pasting process. Building plastering construction and prefabricated board pasting construction are simple and mature construction methods. The present invention is not limited to this, and other types of phase change materials can also be used as long as they can store energy.

[0008] The electric heating film 2 is an electric heating element that directly converts electrical energy into thermal energy. It is usually made of special conductive ink and metal current-carrying strips, etc., between insulating polyester films through processes such as heat pressing, and is a common commodity.

[0009] Technical principle of the present invention. Affected by the low energy flux density and intermittency of solar radiation, the DC voltage generated by photovoltaic modules is low (usually <48V) and unstable. Compared with the AC power transmitted by the power grid, it is usually regarded as "junk electricity". At present, the common practice is to connect the DC power generated by photovoltaic modules to the battery to turn it into stable DC power; then use the inverter to convert the DC power into AC power commonly used in electromechanical equipment; finally, boost the voltage and connect it to the large power grid. The problem is that the economic cost of batteries in the entire technical path accounts for more than 50%; in addition, DC power generates power loss problems in the process of inverting AC. In this regard, the present invention utilizes the resistance element characteristics of the electric heating film, and the "heat storage" and "heat switch" functional material characteristics of the phase change material that can store or release a large amount of latent heat within a small temperature change range, to construct the fish pond wall into a "thermal battery". During the day, the thermal battery unconditionally absorbs and stores the unstable low-voltage DC "junk" electricity generated by the photovoltaic panels in real time. At the same time, the thermal battery controls the rate of heat release to the fish pond through the positive regulation mode of the "heat switch" (the greater the temperature difference, the greater the opening) according to the temperature difference between its phase change temperature and the water temperature of the fish pond.

[0010] Among them, the key parameters of the photovoltaic electric-thermal subsystem are the resistance of the electric heating film 2 as a resistance element, which is intended to be controlled at 4-7Ω to ensure that the photoelectric conversion efficiency of the photovoltaic module is ≥22%; the phase change temperature of the first shaped phase change wallboard and the second shaped phase change wallboard is 26℃~30℃, the phase change latent heat is >180kJ / kg, and the thickness is 45-60mm. The thermal resistance of the insulation layer 3 is controlled at 1-2m·℃ / W to ensure that the electric-thermal conversion efficiency of the electric heating film-phase change thermal storage wall subsystem is >80% and the heat storage efficiency is >90%.

[0011] Working principle of the present invention: The low-voltage direct current generated by the photovoltaic module 4 is converted into thermal energy by the electric heating film 2 built between the first shaped phase change wallboard and the second shaped phase change wallboard, and is stored in the first shaped phase change wallboard and the second shaped phase change wallboard in the form of latent heat. Due to the large thermal capacity of the first shaped phase change wallboard and the second shaped phase change wallboard, a large amount of electric-thermal energy can be stored in a nearly nonlinear manner within a small temperature range, and used to supplement the heat loss caused by the heat dissipation of the fish pond to the outside; the thermal insulation layer 3 is directly attached to the outside of the second shaped phase change wallboard to minimize the loss of heat to the outside.

[0012] The working process of the present invention is as follows: in the heating season, the photovoltaic module-electric heating film subsystem is used to convert the low-voltage direct current electric energy generated by the photovoltaic module 4 into heat energy; then the electric heating film-phase change heat storage wall subsystem is used to store the heat energy converted by the electric heating film 2 in real time in the first fixed phase change wallboard and the second fixed phase change wallboard in close contact with it; when the water temperature of the fish pond drops, the electric heating film-phase change heat storage fish pond system transfers the heat stored in the first fixed phase change wallboard and the second fixed phase change wallboard to the fish pond water body through the fish pond wall in close contact with it in a heat conduction manner, so as to achieve the purpose of flexible heating of the fish pond by photovoltaic electricity-heat energy. During the daytime of the heating season, when the temperature collected by the temperature collector at the electric heating film 2 is greater than 60°C, the relays 6.1 to 6.i are uniformly controlled to be powered off, and the photovoltaic electricity is used for direct current power equipment; when the temperature collected by the temperature collector at the electric heating film 2 is less than 40°C, the relays 6.1 to 6.i are uniformly controlled to be powered on, and the photovoltaic electricity is converted into the heat storage of the first fixed phase change wallboard and the second fixed phase change wallboard. During the non-heating season, the electricity generated by the photovoltaic module 4 is used first to power DC power-consuming equipment 5 such as ventilation machines in aquaculture workshops, LED fish pond fill lights, fish pond water regeneration devices, fish pond oxygen generators, and air source heat pumps. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the principle of the photovoltaic electricity self-generation and self-consumption factory-scale aquaculture tropical fish direct-drive photovoltaic electric-thermal phase change heat storage and heating technology of the present invention.

[0014] Figure 2 This is the structural diagram of the direct-drive photovoltaic electric-thermal phase change thermal storage fish pond for factory-based aquaculture of tropical fish.

[0015] Figure 3 Photovoltaic-thermal subsystem

[0016] In the figure: the first shaped phase change wallboard 1.1, the second shaped phase change wall 1.2, 2 is the electric heating film, 3 is the insulation layer, 4 is the photovoltaic module, 5 is the DC power equipment, 6 is the relay, 7 is the temperature collector, 8 is the temperature sensor DETAILED DESCRIPTION

[0017] The following is combined with Figures 1 to 3 The present invention is described in detail.

[0018] The structure of this system is as follows Figure 1 and Figure 3 As shown, the first shaped phase change wallboard, the second shaped phase change wallboard, the electric heating film 2, the insulation layer 3, the photovoltaic module 4 and the DC power equipment 5 also include a series of relays 6, a temperature collector 7 and a temperature sensor 8.

[0019] The first shaped phase change wallboard and the second shaped phase change wallboard are a kind of cement composite shaped phase change material mortar directly applied on the surface of the building wall, or cast into a prefabricated board and then pasted on the wall of the fish pond. Among them, the cement composite shaped phase change material mortar is a shaped phase change material (see ZL201010210819.2 for details) mixed with cement material to form a cement-based composite shaped phase change material plastering (or cast-in-place) mortar, and the cement-based composite shaped phase change material is directly used as the fish pond wall through the plastering process or the prefabricated board pasting process. Building plastering construction and prefabricated board pasting construction are simple and mature construction methods. The electric heating film 2 is built between the first shaped phase change wallboard and the second shaped phase change wallboard. The insulation layer 3 is directly attached to the outside of the second shaped phase change wallboard. Among them, the key parameters of the photovoltaic electric-thermal subsystem are the resistance of the electric heating film 2 as a resistance element, which is intended to be controlled at 4-7Ω to ensure that the photoelectric conversion efficiency of the photovoltaic module is ≥22%; the key parameters of the electric heating film-phase change thermal storage wall subsystem are: the phase change temperature of the first fixed phase change wallboard and the second fixed phase change wallboard is 26℃~30℃, the phase change latent heat is>180kJ / kg, the thickness is 45-60mm, and the thermal resistance of the insulation layer 3 is controlled at 1-2m·℃ / W. The above matching parameters are determined by the local outdoor meteorological parameters and the thermal performance parameters of the wall, and ensure that the electric-thermal conversion efficiency of the electric heating film-phase change thermal storage wall subsystem is>80%, and the heat storage efficiency is>90%.

[0020] The working process of this system is as follows:

[0021] In the heating season, the photovoltaic module-electric heating film subsystem is used to convert the low-voltage DC power generated by the photovoltaic module 4 into thermal energy; then the electric heating film-phase change thermal storage wall subsystem is used to store the thermal energy converted by the electric heating film 2 in real time in the phase change thermal storage wall 1 that is in close contact with it; when the water temperature of the fish pond drops, the electric heating film-phase change thermal storage fish pond system transfers the heat stored in the phase change thermal storage wall 1 to the fish pond water body through the fish pond wall that is in close contact with it in a heat conduction manner, thereby achieving the purpose of flexible heating of the fish pond by photovoltaic electricity-heat energy. Figure 3 As shown, during the daytime of the heating season, when the temperature collected by the temperature collector at the electric heating film 2 is greater than 60°C, the relays 6.1 to 6.i are uniformly controlled to be powered off, and the photovoltaic power is used for DC power-consuming equipment; when the temperature collected by the temperature collector at the electric heating film 2 is less than 40°C, the relays 6.1 to 6.i are uniformly controlled to be powered on, and the photovoltaic power is converted into the heat storage of the first and second fixed-shaped phase change wall panels. In the non-heating season, the electricity generated by the photovoltaic module 4 is preferentially used to power the DC power-consuming equipment 5 such as the ventilation and ventilating machine of the aquaculture workshop, the LED fish pond fill light, the fish pond water regeneration device, the fish pond oxygen preparation machine, and the air source heat pump.

Claims

1. Factory-scale aquaculture tropical fish direct-drive photovoltaic electric-thermal phase change thermal storage zero-carbon heating system, characterized by: First-shaped phase-change wallboard, second-shaped phase-change wallboard, electric heating film, thermal insulation layer, photovoltaic modules and DC power equipment, also including a series of relays, temperature collectors and temperature sensors; An electric heating film is arranged between the first shaped phase change wall panel and the second shaped phase change wall panel, and the first shaped phase change wall panel serves as the inner layer of the outer surface of the fish pond wall; the wall body has a built-in electric heating film as the middle layer of the outer surface of the fish pond wall, and also includes a thermal insulation layer arranged outside the second shaped phase change wall panel as the outer layer of the outer surface of the fish pond wall; the first shaped phase change wall panel, the second shaped phase change wall panel, the electric heating film, and the thermal insulation layer constitute an electric heating film-phase change thermal storage wall subsystem; Photovoltaic modules, a series of relays, temperature collectors, and temperature sensors constitute the photovoltaic electric-thermal subsystem; Among them, the resistance of the electric heating film is controlled at 4-7Ω to ensure that the photoelectric conversion efficiency of the photovoltaic module is ≥22%; the phase change temperature of the first shaped phase change wallboard and the second shaped phase change wallboard is 26℃~30℃, the phase change latent heat is >180kJ / kg, the thickness is 45-60mm, and the thermal resistance of the insulation layer is controlled at 1-2m·℃ / W to ensure that the electric-thermal conversion efficiency of the electric heating film-phase change thermal storage wall subsystem is >80% and the heat storage efficiency is >90%.

2. The system according to claim 1, characterized in that: In the heating season, the photovoltaic module-electric heating film subsystem is used to convert the low-voltage direct current power generated by the photovoltaic module into thermal energy; then the electric heating film-phase change thermal storage wall subsystem is used to store the thermal energy converted by the electric heating film in real time in the first fixed-shaped phase change wallboard and the second fixed-shaped phase change wallboard in close contact with it; when the water temperature of the fish pond drops, the electric heating film-phase change thermal storage fish pond system transfers the heat stored in the first fixed-shaped phase change wallboard and the second fixed-shaped phase change wallboard to the fish pond water body through the fish pond wall in close contact with it in a heat conduction manner, thereby achieving the purpose of flexible heating of the fish pond by photovoltaic electricity-heat energy; During the daytime of the heating season, when the temperature collected by the temperature collector at the electric heating film is greater than 60°C, the control relay is powered off and the photovoltaic power is used for DC power equipment; when the temperature collected by the temperature collector at the electric heating film is less than 40°C, the control relay is powered on and the photovoltaic power is converted into heat storage for the first fixed-shaped phase change wallboard and the second fixed-shaped phase change wallboard; During the non-heating season, the electricity generated by photovoltaic panels is used to power DC electrical equipment such as ventilation machines in aquaculture workshops, LED fish pond fill lights, fish pond water regeneration devices, fish pond oxygen preparation machines, and air source heat pumps.

Images