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Summer/Winter Design Day Temperature Setpoint Overlap

asked 2016-06-16 17:54:02 -0500

updated 2020-03-07 22:03:21 -0500

For sizing runs in EnergyPlus/OpenStudio, is it possible to have a winter design day temperature setpoint above the summer design day temperature setpoint? It's not atypical to size certain zones to heat to the maximum temperature and cool to the minimum temperature to ensure any temperature within the range can be achieved.

I tried this in OpenStudio and received the following error...

Severe ** DualSetPointWithDeadBand: Effective heating set-point higher than effective cooling set-point - increase deadband if using unmixed air model

My heating thermostat schedule has a winter design day temperature of 75F and my cooling thermostat schedule has a summer design day temperature of 70F. The default profiles are 70F for heating and 75F for cooling.

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answered 2016-06-17 09:46:08 -0500

Archmage gravatar image

In EnergyPlus, the schedules can use the special day types "SummerDesignDay" and "WinterDesignDay" to enter in completely different temperature setpoints for the two types of design days.

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Yes, as stated in the original post I am using the WinterDesignDay and SummerDesignDay with different temperature setpoints (75F in winter and 70F in summer). However I am still receiving the error 'effective heating set-point higher than effective cooling set-point' even though my regular day schedules are the opposite (70F for heating and 75F for cooling). The error happens during sizing.

Lyle K gravatar image Lyle K  ( 2016-06-17 10:46:44 -0500 )edit

For each type of design day, the cooling setpoint needs to be higher than the heating setpoint when using DualSetPointWithDeadband thermostat control method. You can have a heating setpoint of 75F and a cooling setpoint of 80F during WinterDesignDay, and a heating setpoint of 65F and a cooling setpoint of 70F during SummerDesignDay -- all while still running at heating 70 and cooling 75 during the regular simulation.

Archmage gravatar image Archmage  ( 2016-06-17 11:01:43 -0500 )edit

Is there a throttling range for the DualSetPointWithDeadband control method, something that equates to 'effective' setpoint? Is this hard coded or a user input? Haven't been able to find anything concrete in the E+ references. I have some zones where the operational setpoints are 70F heating and 72F cooling, I think this is actually causing my error and not the design days.

Lyle K gravatar image Lyle K  ( 2016-06-17 12:35:13 -0500 )edit

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Asked: 2016-06-16 17:54:02 -0500

Seen: 1,393 times

Last updated: Jun 17 '16