The composite phase change material (PCM) used in thermal energy storage with phase change temperature of 5-15 ℃ are proposed in this paper. The material consists of lauric acid (LA)

decanoic acid (DA)

tetradecyl alcohol (TA) and dodecane (DD)

and the mass ratio of its ingredients is 27.1:28.5:29.6:14.8

respectively. The composite was prepared by ultrasonic oscillations. The properties of the composite were characterized by cooling process

DSC (differential scanning calorimety)

thermal cycling test and so on. The results show that degree of superheat of the composite is close to zero so that it can be ignored; phase change temperature and latent heat of the composite are 5.13 ℃and 154 J/g at 5 ℃/min under a constant and steady stream of nitrogen atmosphere at a flow rate of 10 mL/min

respectively; the composite after 600 cycles deviates the eutectic point without phase separation

so it has better thermal stability; basic physical properties and thermal properties of the composite were gained by a series of property test. Hereby

the composite shows large potential in thermal energy storage

especially in air-conditioning systems

because of high latent heat

suitable phase change temperature

good thermal stability and low cost.