U.S. patent application 20180070659 (inventor Peng Xu, Moraga, Calif.):
"A wearable air temperature control system has two separable parts, a garment and an external heat pump, and the two parts are connected together via a connecting tube. The garment comprises an inner layer, a middle layer which is a carrier supporting the PCM capsules, and an insulating layer. The three layers is secured together to form a laminated unitary structure, which is flexible, soft and breathable. The external heat pump circulates cold or hot water through the garment when the garment is connected. The water flows in the capillary tube embedded in the PCM capsules and recharge the PCM. As a result, the garment could achieve cooling or heating by melting or freezing the PCM material inside the PCM capsules, whether the garment is separated from or connected to the heat pump for recharging. After the garment is fully recharged, the garment can be disconnected from the heat pump which allows wearers to move or work easily outdoors only wearing the portable garment."