Thermal Comfort

Overview

You can watch the Hero v3.1 Webinar section on Thermal Comfort at the 27:46 timestamp below:

https://www.youtube.com/watch?v=2GDotcnaY2c&t=1666s

 

The Thermal Comfort feature comprises the ability to select, run and analyse the results of a specific "Thermal Comfort" simulation profile - typically a "Free-Running" or no heating/cooling profile, that differs from the predominant conditioned Thermal Rating profile used for NatHERS asessments.

When enabled, this Thermal Comfort profile gets simulated in Chenath in parallel with the Thermal Rating profile simulation when you run a Simulation, and it's results stored and treated separately.

The hourly simulation results from that Thermal Comfort simulation are used in the Thermal Comfort Rating that is calculated at the end of the simulation, based on a selected Hot & Cold Comfort threshold set in the Thermal Comfort section of the Results View (see below).

The aim of the Thermal Comfort feature is to allow users to get a measure of the Passive Performance of the project, by the use of a free-running, unconditioned profile. This is a key design metric that cannot be calculated in the conditioned NatHERS profiles, yet is a design attribute that occupants are typically very interested in and that can assist in making better design decisions.

 

Enabling Thermal Comfort

You can enable the Thermal Comfort model by turning on "Enabled" in the Project Data-Grid tab.

When this setting is on, when you Run a Simulation, you will now run an additional Chenath simulation in parallel based on the selected Thermal Comfort "Profile" (Free-running in the example above), that will then be used to calculate the Thermal Comfort Rating.

Due to the nature of the Comfort Rating being based on the hourly zone temperature results, you must have the "Calculate Hourly Results" setting on in addition to the Thermal Comfort enabled setting (however you can have Thermal Comfort off and still have Calculate Hourly Results for Thermal Rating only simulations).

The current available Profiles that can be used are the Thermal Rating profile (i.e. the one used for star-rating calculations, noting that conditioned profiles like this aren't particularly useful to use for comfort metrics as they will generally always be within the conditioned profile temperature bands); the Whole of House all-day and workday profiles (again, these are conditioned profiles), and two types of Free-Running profiles, one without natural ventilation. Note that after a Profile change, you must re-simulate for the changes to have an effect.

The currently available Thermal Comfort profiles that can be used, with the two Free-running (no heating/cooling) profiles being the most useful.

 

Thermal Comfort Thresholds

When a Thermal Comfort model has been simulated, you'll be able to set the Hot & Cold Comfort settings in the Thermal Comfort section of the Results Viewer.

1 Model Thermal Comfort setting

Select to enable the Thermal Comfort model in your Project (duplicated in the Project Data-grid tab's Thermal Comfort Enabled setting).

2 Comfort Profile

Select the simulation type to use for your Comfort Profile such as a free-running profile with no heating or cooling.

3 Show Results & Include Unconditioned Zones Settings

The Show Results setting allows the comfort results to be added to the chart's title for inclusion in reports etc.

The Include Unconditioned Zone setting will include or exclude Unconditioned Zones in the Thermal Comfort calculations.

4 Hot Threshold & Hot Results

The Hot threshold is the temperature setting above which an hourly result will be considered "Hot".

The Results section below the threshold shows the total number of hours per year that the project's zones are "Hot", along with the percentage of the year, and the "DDhrs" or degree-discomfort hours for the project (see below).

5 Comfort Rating & Results

The Comfort Rating is based on the number of hours the project is not hot or cold, and is therefore "comfortable" based on those thresholds. This can be a useful metric to analyse comfort changes from design changes and see their overall impacts on comfort. This result is also shown in the summary results section of the main Hero screen.

Note the Dwelling or Project level average comfort levels are calculated based on the average comfort rating per zone using the zone's actual temperatures, rather than being calculated based on the average temperature of the zones at a dwelling or project level.

6 Cold Threshold & Cold Results

The Cold threshold is the temperature setting below which an hourly result will be considered "Cold".

The Results section below the threshold shows the total number of hours per year that the project's zones are "Cold", along with the percentage of the year, and the "DDhrs" or degree-discomfort hours for the project (see below).

7 Export Options

The export options allow you to take a snapshot image to clipboard of the entire Thermal Comfort section; or alternatively export the data to the clipboard for pasting directly into other applications, or exporting to a CSV file for further post-processing and analysis.

Degree-Discomfort Hours

Degree-discomfort hours is a measure of the temperature differential between the actual temperature and the hot or cold threshold temperatures.

For example if a room had an actual temperature of 32.5 degrees C, and the Hot Threshold was set to 27 degrees C, then the Degree-Discomfort hour is 5.5, which provides a more detailed metric of discomfort rather than just showing "1 hour of discomfort" like when using total hours.

 

Thermal Comfort Results

The hourly results of the Thermal Comfort model can be visualised and analysed in the Results Viewer by selecting the Thermal Comfort results profile on the left side of the Results Viewer. The results in the Temperature chart will then show the results that the Thermal Comfort rating are base on, which are typically an unconditioned free-running profile, and you can analyse how well the design performs without heating or cooling.

The Hot & Cold thresholds will be visually shown in the charts.

 

Likewise in the status bar's summary results section of Hero, you will also additionally see a thermostat icon indicating the Comfort Rating of the Project, in Percentage of the year that the project is within the comfortable temperature band.

Status Bar Results

The image above shows the Thermal Rating results of Star-Rating, Heating, Cooling & Total load, as well as the thermostat icon showing a 59.7% Comfort Rating indicating that for 5236 hours in the year, the project's average temperature was within the comfort temperature band. The project was cold a large portion of year with 3317 hrs or 37.9% of the year under the 18 degree threshold, and being 6328 Degree-discomfort hours.

 

 

 

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