Usage and Thermostat Set Point Help

Modified on Wed, 20 Dec 2023 at 02:18 PM

Usage


These fields do not affect the HERS calculation.  They are used to simulate unique usage patterns of the house to provide a more accurate estimate of energy bills (i.e. for a vacation home).


These are defined using Cron strings.  The Cron string requires 5 values, each separated by a space.  You can either use the * character, which means "all", or use numbers instead of * to narrow down the time period.  The five values are as follows:



For Example:


Cron EntryWhat it means
* * * * 80the set point will be at 80 throughout the year
* * 1-3,9-12 * 72the set point will be at 72 from January to March, and October to December
* 0-14 * 0,6 80the set point will be at 80 for the first half of the month on weekends only
8-17 0-15 1-3,5-7 1-5 80the set point will be from 8am-5pm, for the first half of the month, from January to March and May to July, on weekdays (Mondays-Fridays), at 80



To add multiple set points for one field, enter a second Cron string on a new line.  Any time that is not accounted for with a Cron string will be accounted for by the RESNET default values.  For example, giving the Cooling Set Point  * * 1 - 10 * 80 will set the temperature to 80 for through October, but does not specify a set point for November or December.  As a result, November and December will use the RESNET default set point for that field.


      It is also important to note that the minimum digit in the Chron string parts cannot be greater than the maximum. For
example, if a set point will be at 75 degrees from 11pm through 6am, you would need to enter the period as
0-6,23 * * * 75 NOT 23-6 * * * 75.



Use user-defined data for computing energy usageChecking this box allows you to enter the following inputs.
Cooling Set Point [F]Defines the thermostat set point temperature, in degrees F, when cooling.
Heating Set Point [F]Defines the thermostat set point temperature, in degrees F, when heating.
Lighting and Appliance Usage [MBtu/hr]Energy consumed, in MBtu/hr, by lights and appliances.
Hot Water Tank Temperature [F]Hot water tank heating set point, in degrees F, that defines the desired temperature within the hot water tank.
Hot Water Usage [gallons/hr]Specify hot water used, in gallons / hour, by the occupants.
Internal Gains [MBtu/hr]Net internal gains, in MBtu/hr, from appliances, lighting, solar effects, heat release of occupants, etc.


Default Setpoints


The default set points for different energy codes that Ekotrope uses are as follows:

 

HERS
68F heating, 78F cooling
IECC 200668F heating, 78F cooling
IECC 2009-202172F heating, 75F cooling



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