With the global energy crisis and environmental pollution becoming increasingly severe, the use of renewable energy has been highly valued worldwide. As a clean and inexhaustible source of energy, one of the application fields of solar energy is solar water heaters. Solar water heaters use sunlight to irradiate sunlight and convert heat into heat energy to provide users with hot water. This article will analyze the working principle and system composition of solar water heater in detail.
The basic working principle of a solar water heater
The basic working principle of a solar water heater is to use the thermal energy of sunlight to heat water. It mainly absorbs sunlight through a thermal collector and converts it into heat energy to heat water to a certain temperature. The heated water is then stored in an adiabatic hot water tank for daily use. The process involves the acquisition, conversion, and storage of heat.
1. Calorie acquisition.
Sunlight contains a lot of energy, and when these rays hit the surface of the collector, the material of the collector absorbs these rays and converts them into heat energy. To increase efficiency, collectors are typically coated with black or dark heat absorbers, as dark surfaces absorb sunlight better.
2. Heat conversion.
The collector usually contains a fluid (water or antifreeze) that absorbs heat as it passes through the collector. The heated fluid then flows to a heat exchanger or is stored directly in a hot water tank.
3. Storage of heat.
Heated water needs to be stored so that it can be used when there is no sunlight. The inside of the hot water tank is usually equipped with thermal insulation material, which can effectively reduce the heat loss and ensure the temperature of the hot water.
The system composition of a solar water heater
A complete solar water heater system usually consists of a collector, a water storage tank, a bracket, a piping system, a circulating pump (non-natural circulation system), a controller, and an auxiliary heating device.
1. a collector.
The collector is the most critical part of a solar water heater. It is responsible for capturing solar energy and converting it into thermal energy to heat water or other heat transfer media that flows through its interior. The common types of collectors are flat plate collectors and vacuum tube collectors.
A flat plate collector consists of a metal frame, a transparent cover plate, a heat absorbing plate (usually copper or aluminum plate), and a flow tube. The transparent cover allows solar energy to penetrate and prevents hot air from escapingThe heat absorber plate absorbs solar energy and transfers heat to the water or antifreeze in the flow tube.
A vacuum tube collector consists of a series of vacuum tubes, each with a heat-absorbing tube inside that captures and absorbs heat with extreme efficiency. The vacuum layer can effectively isolate the outside temperature and ensure that the heat is not easily lost.
2. a water storage tank.
A water storage tank is a container used to store heated water, and its interior is usually coated with an insulating layer to reduce heat loss. The volume size of the water storage tank is determined according to the user's hot water demand. Some tanks also have electric heaters or other auxiliary heating facilities in case of rainy weather or when solar heat is insufficient.
3. a bracket. The bracket is the structure used to hold the collector and water storage tank, which needs to be able to withstand the weight of the entire system and be stable under wind and snow loads. The brackets are usually designed with the optimal inclination angle in mind so that the collector can receive maximum solar energy.
4. Pipeline system.
The piping system connects the collector and the water storage tank, and the hot water or heat transfer medium is circulated. In a forced circulation system, the piping also needs to be connected to the circulation pump and controller.
5. Circulating pump.
In a forced-cycle solar water heater system, a circulating pump is used to propel water or antifreeze through the collector and storage tank. The operation of the circulating pump is usually controlled automatically by the controller to ensure the efficiency and safety of the system operation.
6. a controller.
The controller is an intelligent management unit, which can monitor the various temperatures of the system and control the start and stop of the circulating pump according to the set parameters to ensure the effective operation of the system, but also protect the system from overheating or freezing.
7. Auxiliary heating device.
In the case of insufficient sunlight or too low temperatures, solar water heaters may not be able to provide enough hot water. At this time, an auxiliary heating device is required to ensure the hot water. Such a device can be an electric heater, a gas boiler, or another form of heat source.
The workflow of a solar water heater
The specific workflow of a solar water heater is as follows:
1. Heat collection process.
Sunlight hits the collector and converts it into heat energy through the heat absorber plate, which in turn heats the water or heat transfer medium flowing through the heat absorber.
2. Cycle process.
In a forced circulation system, the circulating pump is activated by the controller to push the heated water or heat transfer medium through the piping system to the water storage tank.
In a natural circulation system (thermosiphon system), a density difference occurs because the water becomes lighter when heated, causing the hot water to rise and the cold water to sink, forming a natural cycle.
3. Storage process.
The heated hot water enters the water storage tank and is stored. The insulation inside the tank reduces heat loss and ensures that the temperature of the hot water is maintained at a high level.
4. Use process.
When the user turns on the hot water tap, the hot water in the storage tank will flow out and supply domestic or industrial water.
A solar water heater is an economical and practical hot water system. With proper design and installation, it can provide users with stable hot water in a wide range of climates**, significantly reducing energy consumption and reducing environmental stress. With the continuous advancement of technology and the reduction of costs, it is expected that solar water heaters will be more widely used worldwide.