cwells
09-08-2013, 11:11 PM
Hello,
I work for a company that designs air conditioners for aircraft, and we are setting up a psychometric testing facility to improve our future systems and better characterize the existing ones. We want to be able to determine the steady state cooling capacity of the systems, as well as the pull down times for varying sized air conditioned volumes. The steady state capacity (fixed inlet temperature and humidity) is easy enough, but we are trying to determine now if it is necessary to have an adjustable volume to determine pull down time. The plan is to heat the room to a heat soaked condition (ex. 130 F), and then have a set heat rate added (ex. 22,000 Btu/hr.) while the A/C system is ran to determine the minimum temperature achievable, and pull down time to a given temperature. I was wanting to know, if I can well characterize the system by plotting the heat removal rate vs. the incoming air temperature and also by the moisture removal vs. incoming relative humidity or humidity ratio, can I integrate both of these over the temperature range and get the final pull down time. For example, if I know the enthalpy of the air in the room from the starting point, say 130 F at 50% humidity, and I integrate the heat removal (Btu/hr.) vs. temperature to a final temp of 80 F to get the time and integrate the moisture removal vs. incoming humidity for the same amount of time that I got from the previous calculation to determine the final humidity, I should be able to set determine the theoretical pull down time and room air state. Is this correct?
Hope this makes sense.
Thanks.
I work for a company that designs air conditioners for aircraft, and we are setting up a psychometric testing facility to improve our future systems and better characterize the existing ones. We want to be able to determine the steady state cooling capacity of the systems, as well as the pull down times for varying sized air conditioned volumes. The steady state capacity (fixed inlet temperature and humidity) is easy enough, but we are trying to determine now if it is necessary to have an adjustable volume to determine pull down time. The plan is to heat the room to a heat soaked condition (ex. 130 F), and then have a set heat rate added (ex. 22,000 Btu/hr.) while the A/C system is ran to determine the minimum temperature achievable, and pull down time to a given temperature. I was wanting to know, if I can well characterize the system by plotting the heat removal rate vs. the incoming air temperature and also by the moisture removal vs. incoming relative humidity or humidity ratio, can I integrate both of these over the temperature range and get the final pull down time. For example, if I know the enthalpy of the air in the room from the starting point, say 130 F at 50% humidity, and I integrate the heat removal (Btu/hr.) vs. temperature to a final temp of 80 F to get the time and integrate the moisture removal vs. incoming humidity for the same amount of time that I got from the previous calculation to determine the final humidity, I should be able to set determine the theoretical pull down time and room air state. Is this correct?
Hope this makes sense.
Thanks.