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Hi there, as a member of the OpenStudio Standards Gem development team, including the "Create DOE Prototype Building" measure, we have not gotten to the level of model review to reduce unmet load hours down to ~300 hours/year as some modeling guidelines suggest. Here is a good and general check list for you to consider. https://unmethours.com/question/359/what-are-your-techniques-for-reducing-unmet-hours/#362 In addition, here are a few known or possible causes for the unmet load hours in the prototypes • The night cycling setting may be set to cycle on for certain period of time. If it doesn’t sync with the of the ending of a time step, during the remaining time the HVAC is off, which can cause unmet load.
• For VAV systems using a fixed minimum box minimum, the heating load may not be met because the box is sized for cooling.
• When supply air temperature (SAT) reset for an VAV system is used but the fan sizing is based on regular design SAT, there could be unmet load. • The infiltration schedules (mimicking the door infiltration) for design days should to be checked for sizing period. • There are 90.1 requirements to temporarily disable HVAC or setback thermostat when the someone opens the balcony door during favorable ambient conditions, interlock the HVAC with door switch. The modeling strategy to capture the savings may have been implemented in the OpenStudio prototypes. During the first hour when the thermostat is restored, the load may not be met. There could be a number of reasons for unmet load hours. Some of them are unavoidable to capture some modeling strategies. Our development team have a list of things to review and unmet load is one of them. We will continue upgrade the measure.

Hi there, as a member of the OpenStudio Standards Gem development team, including the "Create DOE Prototype Building" measure, we have not gotten to the level of model review to reduce unmet load hours down to ~300 hours/year as some modeling guidelines suggest. Here is a good and general check list for you to consider. https://unmethours.com/question/359/what-are-your-techniques-for-reducing-unmet-hours/#362 https://unmethours.com/question/359/what-are-your-techniques-for-reducing-unmet-hours/#362

In addition, here are a few known or possible causes for the unmet load hours in the prototypes • prototypes:

• The night cycling setting may be set to cycle on for certain period of time. If it doesn’t sync with the of the ending of a time step, during the remaining time the HVAC is off, which can cause unmet load.
  •
• For VAV systems using a fixed minimum box minimum, the heating load may not be met because the box is sized for cooling.
  •
• When supply air temperature (SAT) reset for an VAV system is used but the fan sizing is based on regular design SAT, there could be unmet load. • load.
• The infiltration schedules (mimicking the door infiltration) for design days should to be checked for sizing period. •
• There are 90.1 requirements to temporarily disable HVAC or setback thermostat when the someone opens the balcony door during favorable ambient conditions, interlock the HVAC with door switch. The modeling strategy to capture the savings may have been implemented in the OpenStudio prototypes. During the first hour when the thermostat is restored, the load may not be met.

There could be a number of reasons for unmet load hours. Some of them are unavoidable to capture some modeling strategies. Our development team have a list of things to review and unmet load is one of them. We will continue upgrade the measure. measure.