The difference between the room condition dew point temperature and the supply air temperature is 7 o F which would be enough to prevent condensation in the room. This is like Psychrometric Chart 7.0 except that the Room Condition is set at 70 o F dry bulb at 55% humidity. Psychrometric Chart 7.0Īt a 4 o F difference in dew point temperature between the supply air dewpoint at 46 o F dry bulb and the 50 o F dry bulb room air dew point would prevent the chances of condensation. This is done by air passing thru a grid of small air passages in a slow rotating heat wheel that absorbs water vapor using impregnated silica gel as a medium to drop the humidity of the air. The purpose of using a desiccant system is to achieve low dew point temperature. In Psychrometric Chart 7.0 shows a Desiccant System. In this case the chilled water supply should be 38 o F / 48 o F to provide a supply air dew point temperature of 46 o F dry bulb. The Chart shows a condition at 70 o F dry bulb and 55% relative humidity. This Case, refer to Psychrometric Chart 6.0, complies with the requirement of SLMC – BGC where the room condition for operating rooms is 70 o F dry bulb between 50% and 60% relative humidity. In Psychrometric Chart 5.0 the same room condition as in Case 1 at 70 o F dry bulb at 50% relative humidity but the chilled water supply is lowered to 35 o F /45 o F in order to provide a supply air dew point 43 o F to prevent condensation. Refer to Psychrometric Chart 4.0 Psychrometric Chart 4.0 Case 2 This case will result to excessive condensation because the dew point temperature of the room condition is lower than the supply air dew point temperature. The room condition is set at 70 o F dry bulb at 50% relative humidity and the chilled water supply temperature is at 45 o F and 55 o F. Psychrometric Chart 3.0 Data Evaluation Case 1 The comparison will be based on an air conditioning system shown below Chart 2, where there is a enough dew point temperature difference between the room condition (about 5 o F) and the supply air dew point to prevent excessive condensation. The process that will be used is thru a Psychrometric Chart Analysis method by comparing different room conditions and plotting an air conditioning system in a psychrometric chart. This report was made to determine the most effective air conditioning system solution to have a room environmental condition for a room at 70 o F between 50% to 60% humidity without having condensation occurring in the operating room. In Chart 2.0, which is the same as Chart 1, except the small dew point temperature difference between the Room Temperature and Supply Air temperature is increased by changing the chilled water temperature setting to 40 o F / 50 o F. At this small difference it is likely excessive condensation occurs especially during rainy season. Psychrometric Chart 1.0Ĭondensation is most likely cause by the small temperature difference between the room condition dew point at 55.4 o F dry bulb and the coil supply air dew point at 53.3 o F dry bulb. The Chart 1 below represents the above condition in a Psychrometric Chart. Their experience was they can meet the temperature at 70 o F dry bulb at 60% relative humidity and there were reports of condensation on the ceiling and walls which later produces molds. This report is presented a room environment condition inside a room to be at 70o F dry bulb at a Relative Humidity between 50 % to 60%.
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