Kempair Group, a China-based company with more than ten years experience in researching and manufacturing air conditioners for the residential and commercial sectors, offers a double wall drinking water heat pump.

The packless Kempair series of coaxial condensers is designed specifically to remove heat from the refrigerant discharge vapor of air conditioning, refrigeration, or heat pump systems for the purpose of heating potable water. The Kempair series employs a "tube-in-tube" design: potable water flows inside a double-wall convoluted copper tube in a counterflow direction to the refrigerant vapor flowing in the annulus between the convoluted tubing and the smooth outer steel tube, called the shell. This counterflow path provides the greatest temperature difference between the two fluids to yield optimum heat transfer.

This series utilizes nested double-wall convoluted tubes having multiple leads: the double-wall isolates the refrigerant from the water to prevent contamination of the water in case of a leak in the convoluted tubing. The convolutions impart turbulence to both the water and the refrigerant flows, while offering all prime surface for maximum heat transfer area with minimum heat exchanger size. According to the company’s press release, it features an air source heat pump water heater and a storage tank.