refrigerant A substance that by undergoing a change in phase (liquid to gas, gas to liquid) releases or absorbs a large latent heat in relation to its volume, and thus effects a considerable cooling effect(一种物质,能在改变物理状态(液体到气体,气体到液体)时释放或吸收相对它的体积来说很大的热量,因此起到降温效果。)