Difference between revisions of "Natural Ventilation Guidelines"
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* List of measured parameters and acceptable range (max-min) where windows enabled | * List of measured parameters and acceptable range (max-min) where windows enabled | ||
* Means of communicating windows enabled* | * Means of communicating windows enabled* |
Revision as of 12:27, 4 June 2012
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Contents
Natural Ventilation Guidelines
Goals
- Provide cooling and air movement when outside air conditions are favorable compared to indoor conditions and GG Inside Design Criteria.
- Prevent condensation from too much humidity in spaces.
- Connect people to indoor air quality and energy use.
- Provide a safe and easy way to unlock and lock windows, open upstairs back windows.
Decisions to be Made
- When can windows be open.
- When should windows be closed.
- Should ventilation and/or radiant floor cooling system also run when windows are open in open office area (hybrid operation mode).
- What are the different procedures in the enclosed offices and restrooms.
- Should all windows be closed and locked after 5 pm.
Expected Outcomes
- Energy savings from not running fans at times.
- Improved indoor air quality by fresh air and air movement in space.
- Comfortable occupants.
Guideline Development
General
- Compare indoor air conditions to outdoor air conditions relative to desired indoor design conditions and determine if windows are "enabled" to be opened if desired by occupants.
- If windows are "enabled" to be opened, indicate so to occupants so they know they can open windows, if desired. Otherwise, windows "disabled".
- Put up a "big ass" pinwheel in the central office space to indicate that conditions are favorable for opening windows.
- Communicate that it is not appropriate to open windows if the pinwheel is not up.
- Include a line on the building operations opening checklist to check for NV conditions and raise or lower pinwheel.
- Develop and communicate special policy related to opening windows in the back conference rooms.
- If windows in these rooms are open, door to central office space should be closed so as to minimize impact on the rest of the building systems and occupants.
- Determine when windows should be closed once open and indicate to occupants.
- Determine systems mode; natural ventilation (NV) only, NV plus mechanical ventilation (low or high speed), NV plus radiant floor, NV plus mech ventil and radiant floor.
Process Measurements
- Outdoor air temperature, humidity, dewpoint, wind speed and direction.
- Forecast for GG area, short term and long term (immediate control and anticipation of where weather is heading to pre-condition building/systems).
- Indoor air temperature, humidity, dewpoint.
- Occupant perception of comfort.
- Coldest typical surface temperatures in space.
Resources Required
- Most reliable forecast - Intellicast
- List of measured parameters and acceptable range (max-min) where windows enabled
- Means of communicating windows enabled*
Guidelines
Outdoor/Indoor Comparison
- Indoor Design Conditions: maximum 76 deg F / 60% RH
- Review daily forecast / hourly conditions predicted: temperature, humidity, dewpoint, wind speed & direction
- Use the following conditions as starting point for when windows may be opened:
- Dewpoint equal to or below 51 deg F
- Outside air temperature below 76 deg F
- Relative humidity accounted for in dewpoint parameter (changes with temperature)
- Look at wind speed and direction in relation to temperature and dewpoint to determine how effective NV might be. May help decision making after observing and trending for a period of time. Higher wind speed that enters the building may make temps closer to indoor design more effective by creating air movement if from a direction that enters the building more readily.
- Initial conditions to use for when windows should be closed:
- Dewpoint greater than 51 deg F
- Outside air temperature equal to or above 76 deg F
- No apparent air movement from having windows open observed
Systems Mode
- Run ERV system with wheel off to augment air movement, especially in rooms without windows or not on windward/leeward side of building.
Forecast
- Use hourly forecast to determine when windows should be closed to hold cooling in and prevent heat from entering (in the summer time, this may be around 10:00 a.m.).
Communication
- "Big Ass" Pin Wheel up when windows may be opened.
- If Pin Wheel not visible, windows should be closed.
References
- NIST NV Article
- Experiment Tracker - summary of all experiments & experiment project management
- Experiment Workbook Template - report template for actual conducting of experiment
Questions
- Dirt?
- Noise?
- Wind blowing papers?
- Security?
TO DO
- Plan / Do / Study / Act / Repeat