Solar Thermal Heating and Cooling
The technology of solar thermal heating and cooling works by capturing sunlight to produce thermal or electrical energy. This alternative energy source is typically converted into heat which can provide hot water and heat homes and businesses. Solar thermal heating is particularly important in delivering hot water in many countries around the world. The advantage of this technology is that it can replace the need for conventional electricity which relies on fossil fuels for production. To trap solar energy, solar water heating collectors are used. Typically these collectors are either connected to glazed or unglazed water systems.
Glazed and Unglazed Systems
The type of system that a country's consumers decide to employ is primarily based on the climatic conditions characteristic of where it will be used. Unglazed systems are made of heavy rubber or plastic and treated with a UV light inhibitor. They do not have any glass covering. These systems are generally less expensive and often used for swimming pools. Glazed systems are made of aluminum plating and copper tubing with a tempered glass covering. These collectors are often used in freezing temperatures.
Most countries utilize glazed water systems. China and India invest in evacuated tube water collectors while others use flat plate collectors. Countries such as Australia and Brazil primarily rely on unglazed water systems while the United States uses unglazed systems for heating swimming pools. Below is a look at some of the countries with the highest capacity of solar water heating collectors.
China has the top capacity for solar water heating, being home to 70% of the world’s capacity for the same. In 2014, the country produced 289.5 Gigawatts-thermal (GWth) which is actually down 18% from the previous year. This is due to a slowdown in retail markets particularly in the rural residential sector and competition with heat pumps. New urban residential buildings drove up the demand for flat plate collectors. Schools, hotels, and universities increased demand for large water tanks on rooftops. These two factors, however, did not surpass the loss created by the rural sector.
The second highest solar water heating capacity holder in the world is the United States with its 4.5% share, a drastic drop off from China’s levels. In 2013, the country finished with 16.7 GWth. The majority of this, 14.6 GWth, was produced by unglazed water systems to heat swimming pools. This country is home to more than half of all unglazed water systems currently in use around the world.
Germany is typically at the forefront of alternative energy production, and when it comes to the use of solar water heating technologies there is no exception to that generality. The 2013 capacity shares equaled 3.3% of the global market, and holds the largest number of new installations throughout the European Union. That, however, is not reflected in growth, as the country actually saw a 12% decline from previous years. Its total Gigawatts-thermal production only increased by .6, ending the year with 12.9 GWth.
Number 4 on the list is Turkey with 2.9% of the world’s capacity for solar water heating. While it may not be the number 1 capacity holder, it did rank second in new installations for 2013. New installations were driven by increased demand in the multifamily housing sector as well as an increased interest in evacuated tube water collectors in the residential sector. This equated to an 18% market growth rate over 2012 levels and an increase of 1.3 GWth. Turkey ended the year with a production level of 11 GWth.
A list of additional top solar water heating capacity holding countries can be found below.