Application of solar energy in swimming pools in China

As a clean and safe permanent energy source, solar energy is highly valued by countries around the world to reduce dependence on non-renewable disposable energy sources such as coal, oil and natural gas. The application of solar energy in swimming pools not only saves a lot of conventional energy, but also shows great economic benefits, and it is of great significance for reducing carbon dioxide emissions and protecting the environment.

China is located in the eastern part of the Eurasian continent in the northern hemisphere. It has a vast territory and abundant solar energy resources. The region with a total annual sunshine hours of over 2200h accounts for more than two-thirds of the country's total area and has good conditions for using solar energy. At present, more and more homes, hotels, swimming pools, public baths and other places use solar energy as the main source of heat for their hot water systems.

(1) China's earliest use of solar energy as a heat source to heat swimming pool water is in the late 1980s, some colleges and universities in Kunming, Yunnan Province, swimming pools, they use the solar collector group directly The pool water is heated. Because at the beginning of the reform and opening up, all technologies were immature, so they were constrained by many technical information and product varieties.

(2) At the beginning of this century, the technology of solar energy for swimming pool water heating developed rapidly. Most of them used indirect heating to heat the pool water in Beijing, Shanghai, Guangdong, Kunming, Zhejiang, Harbin, Shanxi, Fujian, Nanning and other provinces. The city has successful application examples, and applications are becoming more and more common.

1 Beijing No. 9 Middle School

The swimming pool is 50m×15m×(0.8～1.5m), and the water surface area is about 50m2. The new construction adopts the normal pressure oil-fired boiler as the heat source. Due to the high operating cost, the opening time is also limited. To this end, they have modified the pool water heating system, using solar energy to heat the pool water and shower water. The solar collector is an all-glass vacuum tube type, the heat transfer medium is water, and the total area of the collector is 350.4 m2, which is divided into 4 groups, each group consisting of 28 to 29 blocks. In order to ensure uniform heat absorption, the collector group adopts equal-stroke piping. There are 3 6.0m3 hot water storage tanks for temperature difference circulation. The water supply capacity at a water supply temperature of 55 ° C: about 35 m3 / d in summer and about 14 m3 / d in winter. The high-temperature hot water prepared by solar energy is used as a heat source of the swimming pool hot water system, and the water and bath water are heated by the heat exchanger. According to reports, through the market price calculation, for every 1 m3 of hot water of 55 °C, the solar power consumption is 2.2 yuan; while the oil-fired boiler is about 27 yuan, the economic benefit is very significant. At the same time, the opening hours of the swimming pool have been increased, and the social benefits are also obvious. Of course, in the winter, it is necessary to use an oil-fired boiler to replenish pool water and bath water to heat the heat due to solar heat. The ratio of the area of solar collector panels to the surface area of swimming pools used by Beijing No. 9 Middle School is about 0.47:1. Since it was put into use in 2004, it needs to be removed from the heating season (November 15 of the current year to March 15 of the following year). The auxiliary heat source (urban heat network) is turned on, and other seasons auxiliary heat source may not operate. During the transitional season, the water temperature of the pool water can also be maintained above 26 °C, meeting the requirements for use.

2 Beijing Shougang Swimming Hall

It is equipped with a standard swimming pool single building of 50m×21m×(1.2～1.8m). The pool water area is 1050 m2. Vacuum tube collector is adopted. Due to the limitation of roof area, only 250 m2 collector can be set to make up for spring and autumn. In winter, the environmental pollution caused by the single boiler house is not wanted. After comparison in many aspects, the auxiliary heat source of the liquid heat energy generator and the heat network heat source is used, that is, the urban heat network for the heating season; the non-heating Insufficient heat in the transitional season is provided by electricity; from mid-April to mid-October, solar heating is the mainstay. Since it was put into use, it has also achieved good economic benefits.

(2) In recent years, some advanced technology products have been introduced from abroad, including rubber solar collectors and plastic solar collectors, which are directly heated to the swimming pool water, such as the Kunming Military Region Swimming Training Center.

The size of the swimming pool of the Kunming Military Region Swimming Training Center is 50m × 25m × (1.4 ~ 1.8) m, and 312 pieces (each measuring 3.85m × 1.2m = 4.62 m2) of plastic solar energy with a total area of about 1350 m2 are installed on the roof. The collector is still in the trial and debugging stage. The basic situation is that the initial pool water heating time takes about 2 to 3 days (since the auxiliary heat source has not been connected), the pool water temperature is about 26 °C, and there is no air conditioning facility in the hall. Since the swimming pool water is directly heated, the temperature control is relatively simple, and only the pool water temperature is set. When the set temperature is not reached, the solar energy works, and when the set temperature is reached, the solar energy stops working. In order to adapt to the solar energy season, the water in the season exceeds the requirement that the solar energy does not need to be opened. The collector can be connected in parallel. During this period, some of the collectors can be shut down or switched by pipes, and the shower water can be connected to the collector that does not participate in the pool water circulation. Preheating and making full use of solar thermal energy to achieve better energy saving. In winter, solar collectors have low temperature and low heat collection efficiency, so the collectors have no use value. This requires that all the water in the collector should be drained to prevent the pipe from rupturing due to cold freezing in winter. Emptying can be done manually or automatically, which is considered in design.