Data Analysis and Mechanical System Performance. Denver Art Museum August 15-16, 2012

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1 Data Analysis and Mechanical System Performance Denver Art Museum August 15-16, 2012

2 Data Analysis Reading graphs Overlay of indoor and outdoor dew point graphs What you can learn about your mechanical system Which system serves the space Identify night time setbacks and lighting schedules Tracking humidification and dehumidification Understanding the long term effect on collection preservation

3 Why is This Important? Creates meaning data is simply data when you can determine what the data means, that is the basis for decision-making Provides the base for all collectionsconscious optimization/sustainability efforts Tells you if those efforts are working

4 We start with data,

5 and we make it accessible.

6 So, let s start with Temperature and Relative Humidity

7 Title Reading a Graph Major Components what space or dataset am I looking at? Date Range Axes am I looking at this year, last year, all data? X time Y T or RH Scale Of mountains and molehills Key is good documentation will make everything about the graphs easier to analyze

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11 The two questions of preservation environments: What are our conditions? - Often start with Temperature and Relative Humidity for indoor spaces. Why do we have those conditions? - Need outdoor weather, knowledge of mechanical systems, and DEWPOINT.

12 Using Outdoor Weather Data Outdoor weather is the basis for all indoor conditions Brought in on purpose Effect on building through roof, windows, etc. Moisture carried in with outside air or through building envelope

13 Just a little reminder Dew point is a way of representing the absolute moisture content of air The lower the dew point temperature, the less moisture is present The higher the dew point temperature, the more moisture is present. Controlling moisture (dew point) and temperature allows for the successful control of RH

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16 What does flat-lining take? 70 degrees, 50% RH Requires a dewpoint of 50 degrees Can we use the graph to approximate how much work (and when) we need to do to the air (assuming we bring some in from outside)?

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18 How much work? Between 69-71F: 3% of the year Heating: (less than 69F) 79% of the year Cooling: (more than 71F) 18% of the year

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20 How much work? Between DP: 3% of the year Humidifying: (less than 50 DP) 88% of the year Dehumidifying: (more than 50 DP) 9% of the year

21 How much work ARE we doing? Overlaying dewpoint graphs Indoor space dewpoint with outdoor dewpoint Trends (dips and rises) are echoed A cap below high summer dewpoint temps indicates dehumidification A floor above low winter dewpoint temps indicates humidification Transition periods require no work

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23 How the graphs can teach us about systems operation Can see humidification and dehumidification Can help determine when (seasonally) system is performing those functions Can narrow down type of equipment that may be present (chilled water coil, desiccant dehumidification) Can sometimes identify range of chilled water temperature Can determine which spaces are served by same system

24 What equipment do I have? Where are the cap or floor in terms of moisture control? Dewpoint in mid-to-high 40s indicates subcooling, likely (but not definite) with chilled water Humidification is present, but was nonfunctional for a period

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26 What equipment do I have? Flatline dewpoint (for this location) indicates presence of both dehumidification and humidification Dewpoint of low 20s indicates likely use of desiccant dehumidifier

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28 Which System Serves My Space? Overlay DPs from adjacent rooms What to Notice AHUs tend to have a DP signature When same system serves two rooms, DP curves will be nearly identical

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30 Setbacks / Lights Off? Temperature Graphs What to notice Sawtooth patterns Note days of week

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32 Humidifier Not Working? Use DP Graph What to Notice Compare last year to this year

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34 The importance of historical data Allows comparison from year to year Can track mechanical systems performance Documentation of correct or incorrect systems behavior

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36 Indication of equipment malfunction Have shown with humidity (particularly in middle of summer or winter) Can also be reflected in the temperature graph

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38 Changes in Systems Control? Setpoint changes Often manifested in flat-line situations as a step that then plateaus visible in logging of supply air, slightly less pronounced in space.

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40 In summary Data, on its own, doesn t mean much Graphing alone can: Show outdoor environment compared to indoor Provide insight into systems behavior, energy use, controls, and design Allow for comparison of that information from one year to the next.