Abstract
This paper presents a new local space air conditioning system where Coanda Effect of a plane jet is utilized. When the plane jet is discharged from a slot horizontally into a half-confined space opening upward and at the opposite end, the jet is forced to curve and attaches to the floor, forming a cavity space covered by the jet. Applying warm or cool jet, we can use this cavity space for air conditioned working space. When the warm plane jet is discharged, the Coanda Effect does not usually occur due to the influence of buoyancy. In previous paper, we identified the critical conditions, presented as a function of the modified Archimedes number denoted by K, in which this Coanda Effect appears. And we proved that the theoretical analyses regarding critical conditions and the temperature characteristics in the cavity were agreed quite well with model chamber tests. In this paper, we made a series of experiments by using a real size apparatus to test the feasibility of this system. First in heating, the effect of buoyancy on the Coanda Effect was examined and the air temperature in the cavity was measured. Secondly in cooling, when the cool air jet is discharged, the size of the cavity space is decreased by the effect of negative buoyancy of cool air jet. In order to get enough space for working, we identified the value of K for cooling. Thirdly we measured the air velocity in the cavity. It was around 6% of the outlet velocity. Following equation and values are recomended for practical purposes. (Δθ_i)/(Δθ_o)=n((H_s)/h)^<-1/2> Δθ_i: temperature difference between cavity and room air Δθ_o: temperature difference between outlet and room air h: thickness of slot H_s: vertical distance of slot location from floor n: coefficient which depends on heating and cooling conditions. Practical Values of K_c and n [table] ^†standing ^<††>sitting case (A): discharged air is induced from the outside of the cavity space case (B): discharged air is induced from the inside of the cavity space case (C): setting a screen (simulated working table) on the floor in the cavity space for case (A) case (D): setting a screen on the floor for case (B) where K(K_c)=Ar((H_s)/h)^<3/2> Ar: Archimedes Number
