Solar hot water engineering system is mainly composed of solar heat collection system and hot water supply system, including solar water heater engineering heat collector, water storage tank, circulation pipeline, bracket, control system, heat exchanger and water pump and other equipment and accessories. The solar heat collection system is a unique component of the solar water heating system, and it is the key to whether the solar energy is used reasonably. The hot water supply system is responsible for supplying the hot water made by the heat collection system to users. Its design is similar to the conventional domestic hot water supply system. It can be designed by referring to the building water supply and drainage specifications and manuals. In this and the next article, I will introduce to you the design method of discussing solar heat collection system and auxiliary heat source and control system.
Next, let's talk about the classification of solar water heating engineering systems.
According to different classification methods, solar water heating engineering systems can be divided into different forms. Based on the discussion in this article, solar water heating systems can be divided into the following types.
According to the relationship between solar heat collection system and solar hot water supply system, it is divided into direct system (also called primary cycle system) and indirect system (also called secondary cycle system).
Direct system refers to the system that directly heats water to the user in the solar water heater engineering collector; indirect system refers to heating a certain heat transfer working medium in the solar collector, and then using the heat transfer working medium to exchange heat The heater heats the water to supply the user's system. Due to the large resistance of the heat exchanger, indirect systems generally use forced circulation systems. Considering the factors of water sanitation, slowing down the collector scale and anti-freezing, if the investment permits, it is generally recommended to use an indirect system; the direct system is best to explore whether the tap water needs to be softened according to local water quality requirements.
According to the presence or absence of auxiliary heat sources, it is divided into systems with auxiliary heat sources and systems without auxiliary heat sources.
Auxiliary heat source system refers to the combined use of solar energy and other water heating equipment to provide hot water. In the absence of solar energy, water heating equipment relying on other energy sources provided by the system can also provide hot water systems for buildings. What must be emphasized here is that where it is necessary to ensure the quality of domestic hot water supply, auxiliary heat sources are essential. An unassisted heat source system is a system that relies on solar energy to provide hot water. There is no other water heating equipment in the system. Under the condition of insufficient solar radiation, the system cannot produce enough hot water, and the reliability of hot water supply is poor.
According to the starting method of auxiliary energy, it is divided into manual starting system, full-time automatic starting system and timed automatic starting system.
With the rapid development of control technology, the automatic start-up system has gradually occupied the mainstream position in the market.
According to the relationship between the water tank and the collector, it is divided into a compact system, a separate system and a suffocating system.
The smoldering system refers to a system in which the collector and the water storage tank are combined into a single body; the compact system refers to the fact that the heat collector and the water storage tank are independent of each other, but the water storage tank is directly installed on or adjacent to the solar water heater engineering collector System; a separate system refers to a system installed at a certain distance between the water storage tank and the solar collector. In the solar water heating system designed in conjunction with construction engineering, the system used is mainly a separate system.
According to the scope of hot water supply, it is divided into centralized hot water supply system and decentralized hot water supply system.
Centralized hot water supply system refers to a system that supplies water to several buildings, unit buildings, or multiple users; decentralized hot water supply system refers to a system that supplies hot water to a local unit or a single user in a building.
According to the operation mode of the solar heat collection system, it is divided into natural circulation system, DC system and forced circulation system.
Natural circulation system refers to a solar water heating engineering system that uses only the density difference generated by the temperature gradient inside the heat transfer working medium to circulate in the solar heat collection system, also known as thermosiphon system; DC system refers to the heat transfer working medium flowing through once After the heat collector system is heated, it enters a water storage tank or a non-circulating solar hot water engineering system where hot water is used. The forced circulation system refers to the use of external power such as mechanical equipment to force the heat transfer medium to circulate solar heat through the heat collector. Water engineering system.
This article mainly divides and discusses the solar water heating engineering system according to the operation mode of the solar heat collection system.
The design of solar water heating engineering system should follow the principles of water saving and energy saving, economical and practical, safe and reliable, simple maintenance, beautiful and coordinated, easy to measure, according to the use requirements, heat consumption and water point distribution, combined with the building form, other types of available energy And hot water demand and other conditions to choose the form of solar water heating engineering system.