Climate Consultant 4

For over 2,000 locations across the country, there are hourly weather data files packed with temperature, humidity, and wind information that can be used to better match home designs to the conditions they will face. But to say that all this information is dense and overwhelming is a bit of an understatement.

When I teach the Building EnvelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials. course for the Boston Architectural College’s on-line Sustainable Design Certificate Sustainable Design Certificate program, I always seem to be stringing together a bunch of different websites for nationwide climate and weather data. But then I came across the free software, Climate Consultant 4 (CC4)¹. It’s an amazing tool. It takes all that weather data and serves it up in 17 different charts, all of which are clear and compelling visual expressions of the data. Here are some of my favorites.

3-D Charts
Note how the colors categorize ranges of air temperature and how you can use the mouse to rotate the image to think the pattern through from different angles. It’s pretty easy to get a sense of temperature patterns with the data expressed in this 3-D chart.

The drop down menu under "Plot" allows you to use the 3-D chart for seven other weather parameters, like relative humidity and wind speed.

Wind Wheel

The wind wheel can be useful in planning natural ventilation, landscaping, and orientation of entries and tall gables. You can change fields, including month selection, and even a time-lapse expression of all the wind data, at the lower left.

Psychrometric Chart

I think the psychrometric chart is the most useful chart you can generate with CC4 (there is also a great, short tutorial on psychrometric chart basics that you can download here ).

The blue dots strewn across the chart are all of the hourly temperature/relative humidity data points for one year. The dots inside just the dark blue box meet standard thermal comfort conditions (per ASHRAEAmerican Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). International organization dedicated to the advancement of heating, ventilation, air conditioning, and refrigeration through research, standards writing, publishing, and continuing education. Membership is open to anyone in the HVAC&R field; the organization has about 50,000 members. Standard 55This is the ASHRAE standard for thermal comfort, entitled Thermal Environmental Conditions for Human Occupancy. Based in large part on the original work done by P. Ole Fanger, it takes into account all of the factors that affect human thermal comfort: air temperature, mean radiant temperature, relative humidity, air speed, local discomfort, and temperature variations over time (with the first two parameters being the most influential and when combined called operative temperature).). So in Buffalo, for example, there are only 281 hours a year when most folks would not need any form of space conditioning; the outside conditions alone would work.

The green box shows that the design strategy of fan-forced ventilation cooling would add another 655 hours of thermal comfort in Buffalo. You can work your way through all of the strategies, evaluating their individual and cumulative effects on thermal comfort.

And as you go, you can check on prioritized design guidelines that match the strategies you have selected on the psychrometric chart. The first design guideline listed for the psychrometric chart above is #42, recommending the use of ceiling fans.

Ceiling Fan Schematic

Check out CC4 using either sample data weather files or go to EnergyPlus to download the weather file that is closest to your next project. It will either be a pretty good double check on your design or result in some great changes.

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¹ Climate Consultant was developed by the UCLA Energy Design Group and is copyrighted by the Regents of the University of California.