Tracer gas experiments are commonly conducted to calculate the ventilation rate from the difference between indoor and outdoor concentrations. The tracer full article gas method prefers the good mixing of tracer gas inside the building. For those buildings, imperfect mixing would lead to large uncertainty of the resulting ventilation rate measurements. It is very difficult to achieve in naturally ventilated buildings [5]. In this context, it is very important to Inhibitors,Modulators,Libraries find the optimal sampling position for the indoor concentrations.Thus, research is needed for decreasing the sampling positions and finding out the optimal regions in order to estimate the ventilation rate. Buggenhout et al. tested 36 indoor tracer gas sampling positions to find the optimal ones for the ventilation rate using the decay method.
They concluded that the measurement errors can be as large as 86% of the actual ventilation rate by choosing an improper sampling position. The outlet position which gave measurement errors below 10% was found to be optimal. Inhibitors,Modulators,Libraries This study was conducted in mechanically ventilated livestock buildings. Unfortunately, little literature can be referred to for determining the optimal sampling positions in naturally ventilated building [5]. The optimal sampling position of exhaust air in naturally ventilated buildings is very difficult to find, and involves large uncertainty. This is either because the air outlet of Inhibitors,Modulators,Libraries a natural ventilation system may shift with varied wind conditions and opening states, or the inlet and outlet can exist simultaneously at one opening [6�C8].
At present, measurement in such a building requires a lot of sampling positions and expensive multi-point measurements and it is very time consuming. A hypothesis is that the measured values at the optimal sampling positions are representatives for the mean value of the whole-field Inhibitors,Modulators,Libraries indoor concentration [9]. Hence, many scientists have measured several sampling positions inside the building and calculated the average to represent the indoor concentration [5,8]. Due to the non-perfect mixing, large uncertainty still lies in their methods [5].Another difficulty is that the optimal sampling positions may change location when the opening states are modified or the wind direction changes. This is a challenge for us when intending to measure the indoor concentration by using fewer sampling positions.
Therefore, it is necessary to determine the sampling positions independent of the opening states and wind directions.The objective Cilengitide of this study is to find the optimal sampling positions for ventilation rate measurement in a naturally ventilated building. In this research, we focused on the tracer gas measurement method. The investigation includes eight different cases, with four opening states and two wind directions in perpendicular or selleck kinase inhibitor oblique wind directions.