It’s called Thermally Active Building Systems (TABS) and it may be one of the most cost-effective and energy-efficient heating and cooling systems that you never heard of. Think about the concept of a radiant floor. PEX piping is embedded in the floor to heat (and sometimes cool) by radiation and some convection. TABS utilizes PEX pipe too, but instead of being in just the floor, it is embedded into a building’s entire envelope including walls and ceilings.
Like radiant floors, TABS delivers superior thermal comfort. It activates the building’s mass to store and discharge thermal loads. TABS only handles sensible loads, so a proper ventilation system is still required. PEX pipe is made of inert material, so chances that the pipe will last the lifetime of the building is very high.
So why is this system hardly known? After all, heat transfer by water is more efficient than by air. TABS can also utilize more efficient temperatures – about 130F in heating and 58F in sensible cooling – to facilitate heat transfer. Uponor, a leading manufacturer of PEX pipe, has installed more than 1,000 TABS since 1997. That’s still a relatively low number and most of these buildings are located in Europe. Training and case studies with empirical evidence are needed to move TABS forward. I came across a book titled Thermally Active Surfaces in Architecture (2010) by Kiel Moe that I intend to read. This has potential to be a popular design for new construction buildings in the decades to come.
Photos Courtesy of Uponor