Selection and performance of auxiliary heat source for solar heating system in solar water heating project
Issue Time:2019-06-29
Since solar energy is an unstable heat source, it is greatly affected by local climatic factors, and rain and snow are almost impossible to use; therefore, it must be used in conjunction with other energy water heating equipment to ensure a stable hot water supply; The water heating equipment is often referred to as the “auxiliary heat source”, and its function is to supplement the thermal energy of the solar water heating engineering system when the solar energy is insufficient.
Selection of auxiliary heat source for solar heating system

The types of heat sources used in other energy water heating equipments equipped with solar water heating engineering systems should be comprehensively evaluated after technical and economic comparison according to various factors such as the types of conventional energy sources, prices, environmental impacts, and ease of use. Choice, giving priority to environmental protection and energy saving factors.

For buildings that already have centralized heating and air-conditioning systems, the auxiliary heat source of other energy water heating equipment configured in the solar water heating system should be the same or matched with the heat source of the heating and air-conditioning system; the use of waste heat and waste heat should be emphasized.

The capacity of other energy water heating equipment should be determined according to the most unfavorable conditions, that is, the solar heat gain is zero. For underdeveloped areas with low economic and living standards and civil buildings with low requirements for hot water, the requirements may be appropriately relaxed to reduce the capacity of other energy water heating equipment to reduce the initial investment in solar water heating engineering systems.
Solar heating system auxiliary heat source performance

When using pressure boilers and electric heating elements as auxiliary heat sources, there should be a product safety qualification certificate issued by the national quality supervision and inspection agency to ensure the safety and reliability of the operation of the auxiliary heat source system.

When a centralized heat source such as a city heat network is used and a heat exchanger is used as an auxiliary heat source for the solar water heating system, a heat exchanger should be selected, and the heat exchange efficiency should be greater than 90%, and no secondary pollution should be caused; Scale measures.

The auxiliary electric heater for the end user of the distributed water supply system shall comply with the requirements stipulated in "Tempered tubular electric heating element" (JB4088), the working life is not less than 3000h, and the use voltage is 220V or 380V.

The auxiliary heat source shall be equipped with a control device with excellent performance and flexible operation. The auxiliary heat source shall be able to start and stop automatically according to the needs, supplement the shortage of the solar water heating engineering system according to the design parameters, and maintain energy-saving operation. The auxiliary heat source should be easy to maintain and manage, and it is convenient to repair and replace components.