To further understand the nature of inaccuracy in direct measurement, an additional method, termed the multi-sensor measuring grid, is applied.
A measuring grid in the inlet of the supply air duct and riAht out of the RTU is also constructed for the experiments.
Both the MSAT sensor and the measuring grid in the cooling mode are trustworthy for use.
As presented in this case, the measuring grid does not indicate the true value of the SAT.
In summary, the evaluation of the measuring grid further testifies that the offset error for the MSAT in heating mode varies.
Besides, additional construction, costs, maintenance, and sources for uncertainty are incurred by using the measuring grid.
UA of the supply air duct work from the measuring grid to the outlet is assumed to be constant under both cooling and heating modes.
Encapsulated for added durability, the measuring grid
is formed by etching constantan foil, which is then completely sealed in a carrier medium composed of polyimide film.