In recent years, with the popularity of solar water heaters, solar
water heater insulation is increasingly been paid attention.
Thermal insulation layer is not present on the solar water heater
products most frequently asked questions. Solar water heaters heat water tank insulation layer of
polyurethane insulation materials used mostly by the combination of
isocyanate and polyether two materials under certain conditions,
chemical reaction, density 40kg/m3 polyurethane insulation when the
best results. This density polyurethane, the production process for high pressure
and temperature requirements, process difficult to control, if the
simple production equipment, process control is not strict, it will
produce low-quality polyurethane insulation. Some brands of solar water heater production of small and medium
enterprises may use the same materials, but due to technical,
financial strength is limited, poorly equipped, resulting in uneven
foam material, cell rate is very low, too much foam in some places,
easy to heat loss, overnight temperatures can drop 10~ 20 ℃. This poor quality polyurethane insulation in terms of solar water
heaters as "Black Cotton" would not achieve insulation.
Secondly, some of the existing solar water heater products foaming
process has not been high temperature aging treatment. Solar water heaters on the roof, the long-term high temperature
exposure, foam processing if unfamiliar, the reaction is not
sufficient, a second high temperature is likely to foam, extruded
liner inward and outward expansion, burst outside the barrel the skin. Thus, the use of 3 to 5 years after the solar water heater
insulation effect will decline rapidly. As far as I know, because of high temperature aging process will
greatly increase the cost, a great number of solar water heater
manufacturers are omitted in this procedure.
Furthermore, the rapid development of flat plate solar collectors,
but now there are also problems relating to thermal insulation
performance. The flat plate solar collectors generally opt for polyurethane foam
insulation, or rock wool. Although the high temperature heat-resistant rock wool, but the
insulation is limited, in fact, is not the best insulation
materials. If the use of polyurethane foam, will appear as polyurethane to
withstand long-term high-temperature collectors will shrink the
situation has seriously affected thermal performance.
As the phenolic foam in recent years developed a new insulation
material, is not known for the solar industry, phenolic foam
applications in the solar industry is also unusual.
U.S. good source of phenolic foam applications in solar energy has
already begun. Technology Department, said the officer, because they have
recognized the advantages of phenolic foam, phenolic foam is
considered as a solar water heater tank insulation. The company is also stepping up research and development for
phenolic foam insulation tanks and casting equipment, pouring foam
material, is expected to soon be able to provide companies in the
solar water heater equipment, raw materials and technology.
As for the flat plate solar collectors, the U.S. produced good
source of phenolic foam composite board (the middle layer of
phenolic foam insulation, aluminum foil on the surface and bottom
surfaces of composite galvanized steel or aluminum) can be applied
directly. Since the plate has been back with the collector box with composite
materials and aluminum materials, simplifying the collector of the
production process. And phenolic foam insulation is a professional manufacturer of
preformed insulation materials, the quality can be guaranteed.
It is worth mentioning that the price of basic and phenolic
urethane foam flat, that is, improve performance, while the use of
phenolic foam foam do not increase costs to the enterprise.