At present, there are many kinds of domestic solar water heaters sold in the market, which can be divided into vacuum tube type and plate-type according to the type of solar collector. According to the structure, can be divided into one - style and split type; According to the production process, it can be divided into pressure type and non-pressure type. At present, the most common household solar water heater sold in the market is non-pressure vacuum tube household solar water heater. When choosing a household solar water heater, we should pay attention to the following points:
1. In the thermal performance index, the higher the "average daily efficiency", the better the "average thermal loss coefficient".
2. The key components of household solar water heater is all-glass vacuum solar thermal collectors (vacuum tube), vacuum tube quality directly affect the performance of the whole household solar water heater. When the choose and buy should be carefully observed the vacuum tube coating on glass tube, this layer is called solar selective absorbing coating, because each manufacturer production process is different, the coating color is different, but basically it black, dark blue or dark grey, uniform color, good quality coating film scratches, peeling or falls off phenomenon, there are no stones or knot phenomenon on the glass, the support of support inside the glass tube placed correctly and not loose.
3. Also pay attention to the pipe spacing between the vacuum tubes, and the center distance between the two tubes is about 70mm.
4. The bracket design of domestic solar water heater should be reasonable, and sufficient strength and rigidity should be required to ensure sufficient bearing capacity. In some areas of daily wind power, especially in coastal areas, it is important to pay attention to the design of solar water heater.
5. On the market at present, domestic solar water heater reflector form is varied, with plane reflector, curved reflector, embossing aluminum plate, etc., should be paid attention to when the choose and buy products reflector design whether can make full use of the vacuum tube heat surface, vacuum tube can be the maximum extent by light.
6. The number of permanent residents in the home should also be considered in order to determine the water capacity of the household solar water heater. Generally the standard of 40 litres per person is appropriate. In addition, many products of the nominal water capacity is calculated for each vacuum tubes of the addition of capacity and the water tank capacity calculated, but under the water heater outlet and the vacuum tube water cannot be put out of use, users can actually use to water is only between the nozzle and the overflow mouth water, so when the choose and buy should ask vendors, their nominal water capacity refers to the total actual can use water capacity, water capacity or both differ much.
7. If the purchased solar water heater needs to be equipped with electric heating device, the product with electrical safety design should be selected.
8. Choose and other related accessories, such as automatic water device, water temperature, water level display, solenoid valve, etc., for the choice of these devices should be careful, some function appears to be advanced, but too many components, the reliability is not high, over time, easy to a problem, when the choice must ask life and warranty period.
9. Good after a home solar water heater of choose and buy, should be paid attention to during the installation process support whether the installation is firm, all whether to tighten the screws and connectors, fluctuation conduit installation location is reasonable, whether there is water heater itself reinforcement measures and so on. In addition, a check device must be installed in the upper water line to prevent hot water backflow and pour into the cold water pipe.
10. After-sales service of domestic solar water heater is also very important. Best choice of well-known brand products and after-sales service dealers. Because household solar water heater is durable consumer goods, and often is installed on the roof, once out of trouble, the user is difficult to solve by oneself, so after sale service must have safeguard. At present, the free warranty period in the market is usually 3 ~ 5 years.
11. Since the household solar water heater is installed outdoors for a long time, the vacuum tube will be contaminated with dust or impurities, thus reducing the absorption efficiency. Therefore, the vacuum tube of the water heater should be cleaned regularly, especially in areas with snow in winter. If be affected by the house design, oneself can't clean, should ask the dealer, after sale service whether contain to have periodic clean one item.