Abstract: a solar water cooler that uses solar energy directly or indirectly to cool the water
consists of a cool water storage tank, a condensing wall, an auxiliary refrigeration device, with
an insulating board dividing the cool water storage tank into an upper water-cooling tank plus a
lower water freezing tank. The system provides a solar water cooler with a dual-temperature
cool water tank that reduces the water temperature to the minimum temperature of the day via
heat dissipation, plus the obtained minimum-temperature water is delivered directly for cooling
purposes or delivered onto the condensing device as cooling water to improve the cooling
efficiency. The auxiliary refrigeration device helps reduce the water temperature when the
cooling water does not reach the required temperature for the air conditioner for refrigeration
purposes. The major tasks of this study are to reduce the temperature of the cooling water to
lower than the minimum temperature of the day plus increase the required temperature of the
air conditioner for refrigeration to save energy. With these two challenges solved, most areas in
the global can use air conditioners with solar water coolers for cooling purposes, thus
alleviating global warming plus benefiting the whole global population.
- Introduction
In recent years, with fast economic growth, urban power demand surges, plus the power consumption
by air-conditioning systems in urban buildings take a large proportion – higher than 50% of the total
power consumption of buildings. In the peak season in summer, the power consumption of air
conditioning systems in northern China takes up 16% ~ 18% of total power consumption in cities, and
that in developed cities in southern China (Guangzhou, Shenzhen, etc.) takes up a proportion of over
30%. Air conditioners consumes large amounts of power, plus peak hours of cooling load coincide
with the peak hours of urban power consumption, which exacerbates the supply-demand imbalance of
power plus aggravates the power shortage in peak hours. To relieve this grave situation, the Chinese
government has taken a series of measures: in 1994, the State Development Planning Commission and
the Ministry of Electric Power decided to differentiate the price of electric power in peak plus valley
seasons to “balance the peak plus valley”. The Northern China Electric Power Group first stipulated
that ratio of the power price in the peak season to that in the valley season is 4.5:1; after that, many
electric power departments followed suit plus released some preferential policies. Driven by these
initiatives, the cool storage air-conditioning technology gained rapid progress [2].
Since the 1980s, cool storage air-conditioning technology has developed rapidly plus improved in
developed countries around the world. Given the experience of the US, Japan plus Taiwan, one
important solution to solve the power demand-supply imbalance is to develop cool storage air
conditioners. Take Japan as an example: in this decade, Japan has built or renovated over 3000 cool
storage systems, increasing the power utilization rate in valley seasons to 45%; South Korea issued
laws that public buildings covering an daerah of over 3000 m2 must use cool storage air-conditioning systems. In 1990s, cool storage air-conditioning technology began to gain momentum in China; large
provinces plus cities including Shenzhen, Beijing, Guangzhou, Zhejiang, Shanghai, Tianjin, Wuhan
and Fujian initiated several large- or medium-scale cool storage central air-conditioning programs
which achieved good economic efficiency plus were promoted in more than 20 provinces across China.
The current situation shows that the users plus the electric power departments have provided positive
feedback for these programs.