Solar high-efficiency dual temperature phase-change collector and phase-change material for collector

The invention discloses a solar high-efficiency dual temperature phase-change collector, which comprises a water inlet header, a guide pipe, a heat exchange pipe, a water outlet header, evacuated collector tubes and heat accumulators, wherein the heat accumulators are arranged inside the evacuated collector tubes, and respectively comprise an intermediate temperature phase-change material filling cavity and a high temperature phase-change material filling cavity to form a dual temperature phase-change system; composite paraboloid condensers are arranged outside the evacuated collector tubes along the axial direction. The invention also provides a high temperature phase-change material, which comprises the following components in percentage by weight: 2 to 4.5 percent of nanocrystalline metal copper, 1 to 2 percent of dispersing agent and the balance of erythritol, wherein the dispersing agent comprises oleic acid and lauryl sodium sulfate in a weight ratio of 1:1. Each heat accumulator of the collector has an intermediate temperature side and a high temperature side, the two sides are filled with phase-change materials in different phase-change temperatures, a pipeline structure for heating cold water sequentially is designed, and the gradient utilization of energy is achieved; energy storage materials, the evacuated collector tubes and the composite paraboloid condensers are combined to greatly improve the effective utilization rate of solar energy.