Re: [EnergyPlus_Support] Problem of Zero Design Cooling & heating Load

Sheelam,

Typically this problem arises when design day schedules and thermostats are not used, and rarely is it the case that there are not actually any heating or cooling loads for a space.. (once in a while there can be no heating or cooling load, but not both)

For trouble shooting and general best practice for HVAC design calculations in Energy Plus: The first thing to do is to make sure you do not have dual setpoint thermostats for design days. Then, check if your heating design day schedule for heating has all internal loads off (or a reasonably low fractional values) and no solar design model so that it represents a worst case cold condition. Then check if your cooling design day schedule has all internal loads on (or a reasonably high fractional values) and solar design model so that it represents a worst case hot condition. This assumes you are using ASHRAE design day conditions.

Below are some examples:

Name	Summer Design Day in Annarbor	Winter Design Day in Annarbor
Month	7	1
Day of Month	15	15
Day Type	SummerDesignDay	WinterDesignDay
Maximum Dry-Bulb Temperature	29.5	-5
Daily Dry-Bulb Temperature Range	11.5	0
Dry-Bulb Temperature Range Modifier Type
Dry-Bulb Temperature Range Modifier Day Schedule Name
Humidity Condition Type	WetBulb	WetBulb
Wetbulb or DewPoint at Maximum Dry-Bulb	24.5	-5
Humidity Condition Day Schedule Name
Humidity Ratio at Maximum Dry-Bulb
Enthalpy at Maximum Dry-Bulb
Daily Wet-Bulb Temperature Range
Barometric Pressure	98287.2	98287.2
Wind Speed	0	3
Wind Direction	0	0
Rain Indicator	No	No
Snow Indicator	No	No
Daylight Saving Time Indicator	No	Yes
Solar Model Indicator	ZhangHuang
Beam Solar Day Schedule Name
Diffuse Solar Day Schedule Name
ASHRAE Clear Sky Optical Depth for Beam Irradiance (taub)
ASHRAE Clear Sky Optical Depth for Diffuse Irradiance (taud)
Sky Clearness	0.98	0

Name	Winter Design Setpoint	Summer Design Setpoint
Schedule Type Limits Name	Temperature	Temperature
Field 1	Through: 12/31	Through: 12/31
Field 2	For: WinterDesignDay	For: SummerDesignDay
Field 3	Until: 24:00	Until: 24:00
Field 4	21.111	24.444
Field 5	For: AllOtherDays	For: AllOtherDays
Field 6	Until: 24:00	Until: 24:00
Field 7	21.111	24.444

Name	TopFloorThermostat	BottemFloorThermostat
Zone or ZoneList Name	TopFloor:Zone5	MainFloor:Zone3
Control Type Schedule Name	Zone Control Type Sched	Zone Control Type Sched
Control 1 Object Type	ThermostatSetpoint:DualSetpoint	ThermostatSetpoint:DualSetpoint
Control 1 Name	Dual Setpoint	Dual Setpoint
Control 2 Object Type	ThermostatSetpoint:SingleCooling	ThermostatSetpoint:SingleCooling
Control 2 Name	Cooling Design Setpoint	Cooling Design Setpoint
Control 3 Object Type	ThermostatSetpoint:SingleHeating	ThermostatSetpoint:SingleHeating
Control 3 Name	Heating Design Setpoint	Heating Design Setpoint
Control 4 Object Type
Control 4 Name

Name	Heating Design Setpoint
Setpoint Temperature Schedule Name	Winter Design Setpoint

Name	Cooling Design Setpoint
Setpoint Temperature Schedule Name	Summer Design Setpoint

Jeremiah D. Crossett | Senior Analyst | Phase Change Energy Solutions

120 E. Pritchard St. | Asheboro, NC 27203

| Mobile 503-688-8951
www.phasechange.com

On Thu, Dec 5, 2013 at 6:13 AM, sheelam khare <sheelam_khare_26@xxxxxxxxxxx> wrote:

Hello All,
I am using the Energy Plus software to simulate the energy performance of the Civic Center Building located in Barcelona, Spain.
In the results, the design Cooling & Heating load for two zones are coming as Zero. I have tried to resolve this in many ways but unable to solve this.

Please give your valuable suggestions to solve this problem.

Thanks with regards....
Sheelam Khare