a) A solar thermal system.太陽能熱系統。
Solar energy technology generally includes photothermal and photoelectric applications. Solar photovoltaic technology uses the photoelectric effect of solar cells to directly convert solar radiation into electricity and apply it in the form of electricity, while photothermal technology uses various forms of collector technology to collect and store solar radiation as heat energy. The energy form of solar radiation directly applied by solar thermal technology is thermal energy, which can be used for heating, cooling, air conditioning and thermal power generation, etc. In the technical implementation and engineering application of solar thermal technology, thermal storage technology is not only a necessary part of the utilization of solar thermal, but also a kind of independent existence and development of special technology, which occupies an important position and is applied in a wide range of engineering technology fields. The energy saving application of solar thermal storage is widely adopted and developed, which is a kind of efficient and environment-friendly energy-saving technology measure. Solar thermal storage technology has great potential, and many engineering technologies are gradually developed and utilized as energy saving and environmental protection measures.
The so-called solar thermal storage technology refers to the energy storage technology that stores the solar heat that has been converted and collected by certain technical devices, and can be used in the form of non-ready-to-use, at the time of weak solar radiation or at night without solar radiation, or after a long period of time, such as through seasonal conversion, and can be re-used. The heat storage of thermal storage technology, its use time relative to conversion collection time, can delay preservation, long-term standby. Solar thermal storage technology can overcome the application limitations such as solar radiation intermittency and regional differences in solar energy utilization, improve the possibility and application efficiency of solar energy technology utilization, and the implementation of many engineering technologies can be more energy saving and environmental protection. Solar thermal storage technology can be applied in a wide range of fields such as building energy saving and green building, heat pump, refrigeration and air conditioning, which greatly improves the energy-saving and environmental protection effect of engineering equipment system in these fields.
Solar thermal systems are usually hot water and hot air systems. The difference of two systems: the collector heating medium is different, hot water system set up hot water collector, use of solar heat to heat water for users to use hot water, air air collector system setting, collect solar thermal heating air, two types of systems can get hot water and hot air, can be directly or indirectly to hot water heating, heating, drying, life form and so on a wide range of applications. Solar thermal storage technology can be applied in a wide range of user areas of solar thermal hot water and air systems to save energy and protect the environment, improve system efficiency and enhance system functions. For example, in the solar hot water system, the simplest solar hot water latent heat storage is to set the PCM material at the bottom of the hot water tank. When there is solar heat irradiation, the water heats up and the PCM material absorbs heat and stores heat. When there is no solar radiation, the PCM material flows into the water tank and heats up with cold water, thus achieving energy saving of heat storage and release. Various measures are adopted to improve the heat transfer efficiency of the heat storage tank. Various forms of open and closed loop complex systems are continuously developed and applied. The independent thermal memory of PCM material is used to store heat and release heat. For solar thermal air systems, both sensible heat and latent heat storage can be used in solar thermal systems. The heat storage capacity of PCM material can be reduced by using the sensible heat storage mode of rock, water and other heat storage materials. The corresponding drying device is set and the solar air heat collecting system with phase-change latent heat storage is adopted. The solar heat can be used to dry tobacco, vanilla and crops without sun exposure. The solar air heat collecting principle of phase-change latent heat storage can be used in the design of solar house technology measures for building energy saving. For example, the application of finalized phase-change thermal storage materials in the ceilings and walls can directly benefit air heat collection and regulate indoor temperature environment with solar heat storage and release, which can reduce building energy consumption.
Solar thermal storage for building energy conservation is an important technical measure for building energy conservation at present. For example, the application of phase-change thermal storage technology will generate huge energy saving effect and great potential for application. Phase-change thermal storage materials can be widely used in building energy conservation. The principle is to improve the heat storage and release of building envelope to solar heat, geothermal and other renewable energy sources, increase the solar heat available for utilization, so as to reduce the load of building heating and air conditioning and achieve building energy conservation. For example, tromb wall is an effective solar energy building technology that absorbs and stores solar heat for building energy conservation. By setting up thermal interlayer of building envelope to collect and circulate solar heat for heating heat collection and distribution. The use of phase-change thermal storage materials in the wall materials of trombe wall can enhance the heat storage and release capacity of the wall, so as to absorb and utilize more solar heat, realize the reduction of heating heating and cooling and heating load of air conditioning, and improve the building energy efficiency. Phase-change thermal storage materials can be applied to wall and window structures. For example, a shutter that is opened at night during the day, a phase-change thermal storage material absorbs solar heat, and the shutter is closed at night, which is insulated from external heat, and the heat is one-way to indoor heating. The shaped phase-change thermal storage materials can be applied to the heating function floor for the use of electric load regulation or solar heat storage to reduce building energy consumption and operation cost. The ceiling structure on the top of the building USES phase-change thermal storage materials to store and release solar heat, which can reduce the heating load of the building.
b) A solar photovoltaic system
The reality is that radiant energy is changing, and solar cells are energy conversion components with no storage function, so their output is changing all the time. The calculation of photovoltaic power generation capacity is based on the conversion efficiency of different types of panels (17% for monocrystalline silicon, 15% for polycrystalline silicon and 8% for thin film cells), which can only give an average value. Where defined: AM -- atmospheric mass, or volume ratio, pressure ratio, or distance ratio under the same horizontal section. The length of the path of direct sunlight through earth's atmosphere is expressed as a multiple of the length of the path of the sun through the atmosphere to sea level at the zenith.
1) off-grid system
(1) off-grid system without battery, the selection of solar cell module should consider the start-up and overload performance of electrical equipment, and the output current of the solar module must ensure the need of starting current. Since the solar modules have limited overload capacity and the short circuit current is usually no more than 1.2 times the rated current, the panel's capacity needs to be large.
(2) off-grid system with battery, the solar cell component can only be considered under normal working condition to meet the power and service time requirements of the electrical equipment. That is, the power generation capacity of solar panels should be able to meet the requirement of energy consumption of electrical equipment throughout the day. The battery should not only consider the discharge current to meet the starting requirements of the electrical equipment, but also the capacity of the battery should meet the requirement of all-day sunless time to ensure the power consumption of the electrical equipment. Basic principle: the capacity of solar modules should be enough to collect enough energy for the whole day when there is sunlight during the day. The sun appears in a cycle of 24 hours, so we can calculate the solar module capacity in a day. During the effective time of solar irradiation, the power of the equipment shall be ensured, and the battery shall be charged to the rated capacity within the effective time. The energy of the battery should be used for the rest of the time. The capacity of the solar cell module is selected according to the standard test condition and the average daily sunshine time is 5h. For example, the power equipment is 10kW, the power consumption is 240kWh, and the solar cell capacity is 240/5=48kW. The storage capacity of the battery shall meet the requirement of 190kWh of electrical equipment within 24-5=19h without lighting time. If the battery terminal voltage is 220V, the battery capacity is about 900Ah. The above is the result calculated under ideal conditions with a period of 1 day. If you consider the maintenance factor, cloudy conditions of rain, but also consider the appropriate margin.