Eutectic salt cold-storage material

Abstract

The invention provides an eutectic-salt cool-storage material, comprising sodium sulfate decahydrate (Na2SO4 question mark 10H2O), ammonium chloride (NH4Cl), sodium borate decahydrate (Na2B4O7 question mark 10H2O), and silica gel (mSiO2 question mark nH2O); the eutectic-salt cool-storage material is characterized in that: according to the mass percentage, the eutectic-salt cool-storage material comprises 72.86 percent of Na2SO4 question mark 10H2O, 12.86 percent of NH4Cl, 2.86 percent of Na2B4O7 question mark 10H2O and 11.42 percent of mSiO2 question mark nH2O. The transformation temperature of the eutectic-salt cool-storage material is 8.47 DEG C, the undercooling degree thereof is 2.41 DEG C and the transformation latent heat thereof is 136.07-182.73Kj / kg. Owning to low transformation temperature and small undercooling degree, the material is the eutectic-salt cool-storage material applicable to cold accumulation air-conditioning systems.

Description

technical field [0001] The invention relates to a eutectic salt cold storage material, which is mainly used as a cold storage medium in a cold storage air conditioning system. Background technique [0002] Cold storage air-conditioning technology is to use the cheap electricity in the "low valley" at night to operate the refrigeration unit, and the cold energy generated is stored in the cold storage medium; the cold energy is released during the peak hours of the day to provide the building's air conditioning load, and to achieve "peak shifting and valley filling" in power operation. role. It not only relieves the pressure of the urban power grid, but also saves the operating cost of the air conditioning system for the user, which has good economic and social benefits. [0003] Cold storage media commonly used in air conditioning projects include: water, ice and eutectic salt cold storage materials. Water storage uses the sensible heat of water to store cold. The main disa...

AI Technical Summary

Problems solved by technology

Water storage uses the sensible heat of water to store cold. The main disadvantage is that the cold storage capacity is small (the specific heat of water is 4.18kJ / kg℃), and the volume of the cold storage tank is large; the ice storage uses the latent heat of ice to store cold, and the cold storage capacity is large (334kJ / kg ), the volume of the cold storage tank is small, but the evaporation temperature of the refrigeration unit of the ice storage system is low (generally about -10°C), which reduces the efficiency of the unit; The temperature change coincides with the evaporation temperature of the water storage unit, which is about 7°C to 9°C, and phase change cold storage can be realized without reducing the efficiency of the unit; at the same time, the latent heat of phase change of eutectic salt is generally about 100kJ / kg, so , eutectic salt cold storage has the advantages of both water cold storage and ice cold storage, and is a promising cold storage material. However, some problems in the commonly used eutectic salt cold storage materials restrict the practical application of this technology: phase change The temperature is too high (often above 10°C), which is difficult to meet the requirements of the cold storage air conditioning system; the supercooling degree is relatively large (above 4°C), which causes the evaporation temperature of the refrigeration unit to decrease and the efficiency of the unit to decrease