Re: [EnergyPlus_Support] Way to interprete the moisture load rate in the output file

Actually the Zone/Sys Moisture Load Rate Predicted should be the same as either (2) or (3) or be equal to 0, but I don't see that using these numbers. To convert kgwater/s to Watts, multiply by the heat of vaporization of water. Approximately 2.2E6 - 2.5E6 depending on the zone temperature and humidity ratio.

Did you read the report variable descriptions in the Input Output Reference document? Just search for the report variable name.

Zone/Sys Moisture Load Rate Predicted[kgWater/sec]
This is the predicted latent (moisture) load in kgwater/s required to meet the current zone humidistat setpoint. A positive value indicates a humidification load, a negative value indicates a dehumidification load. For a dual setpoint humidistat, the value is zero when the controlled zone’s relative humidity is between the defined humidifying and dehumidifying setpoints. This moisture load rate is calculated and reported from the Predict step in the Zone Predictor-Corrector module. For nearly all equipment types, the Predictor-Corrector evaluates the active humidistat setpoints, determines if the zone requires humidification or dehumidification, and then passes this single load to the equipment for the single setpoint humidistat case. This value is not multiplied by zone or group multipliers.

Zone/Sys Moisture Load Rate Predicted to Humidifying Setpoint [kgWater/sec]
This is the predicted latent (moisture) load in kgwater/s required to meet the current zone humidistat humidifying setpoint. This is calculated and reported from the Predict step in the Zone Predictor-Corrector module. For nearly all equipment types, the Predictor-Corrector evaluates the active humidistat humidifying setpoints, determines if the zone requires humidification or not, and then passes this load to the equipment for the case of a dual setpoint humidistat (see Zone/Sys Moisture Load Rate Predicted, above, for single setpoint humidistat case). This value is multiplied by zone or group multipliers.

Zone/Sys Moisture Load Rate Predicted to Dehumidifying Setpoint [kgWater/sec]
This is the predicted latent (moisture) load in kgwater/s required to meet the current zone humidistat dehumidifying setpoint. This is calculated and reported from the Predict step in the Zone Predictor-Corrector module. For nearly all equipment types, the Predictor-Corrector evaluates the active humidistat humidifying setpoints, determines if the zone requires dehumidification or not, and then passes this load to the equipment for a dual setpoint humidistat (see Zone/Sys Moisture Load Rate Predicted, above, for single setpoint humidistat case). This value is multiplied by zone or group multipliers.

On 1/12/2012 3:27 PM, techneeer12 wrote:

Hello All

Just some background, my model has dual humidity setpoints such that the humidifying setpoint is 33(%) and the dehumidifying setpoint is 69(%). The output file came out after running my model, displaying three measures such as: (1) Zone/Sys Moisture Load Rate Predicted (2) Zone/Sys Moisture Load Rate Predicted to Humidifying Setpoint (3) Zone/Sys Moisture Load Rate Predicted to Dehumidifying Setpoint.

However, I run into a difficulty in understanding those aforementioned three measures. For example, if the case is the same as described below, what implication can I get from the results?

(1) Zone/Sys Moisture Load Rate Predicted: -0.00118 (kg_water/sec)
(2) Zone/Sys Moisture Load Rate Predicted to Humidifying Setpoint:
-0.11435 (kg_water/sec)
(3) Zone/Sys Moisture Load Rate Predicted to Dehumidifying Setpoint:
0.02154 (kg_water/sec)

where, isn't it that (1) should be the sum of (2) and (3)?

In addition, is it right if I try to convert these kg_water/sec values into energy consumption? Somehow, I think I can make it because dehumidifying or humidifying equipment may need the electricity consumption. Am I correct? If so, please let me know how to convert them.

Thank you in advance
Ahrong

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