EnergyPlus Errors and Warnings

1

** Severe  ** Did not find "Until:  22:00" in list of Objects

You may have entered a semi-colon character (;) at the end of one of the lines in a Compact schedule when you meant to enter a comma (,).

2

** Severe  ** Problem in interior solar distribution calculation (CHKBKS)

**   ~~~   **    Solar Distribution = FullInteriorExterior will not work in Zone=78474

**   ~~~   **    because vertex 3 of back surface=W_73536_2_0_0 is in front of receiving surface=W_78474_3_0_0

**   ~~~   **    (Dot Product indicator=1.4966)

**   ~~~   **    Check surface geometry; if OK, use Solar Distribution = FullExterior instead.

The 3-Full interior and exterior solar distribution option is selected but one or more zone in the model is non-convex. Note that DesignBuilder is configured by default to check for this condition and provides more friendly error messages.

3

** Severe ** For Ideal Loads ZONE 21438 Ideal Loads serving Zone 21438

** ~~~ ** ..the supply air temperature for cooling [10.00] is greater than the zone cooling setpoint [8.99].

This severe error can occur when using Simple HVAC, or Cooling design calculations with Operative control in zones with strong radiant heat gains causing high radiant temperatures (e.g. un-insulated roof or zone is highly glazed). The supply air temperature is fixed (to 10°C in the above example) but the zone air temperature must be cooled lower than this (8.99°C in the above example) to give the required operative setpoint (.e.g. 24 °C). Operative temperature, Top, is calculated as:

Top= 0.5 x (Ta + Tr)

where:

Top is the operative temperature.

Ts is the air supply temperature.

Ta is the zone air temperature (Ta must be > Ts).

Tr is the zone radiant temperature.

So there is a requirement:

Tr max <= 2 Top - Ts

If the zone radiant temperature is higher than Tr max and Operative temperature control is used then this severe error will occur.

The solution may be to use Air temperature control and to reduce the radiant temperatures using solar shading/insulation as appropriate.

See the discussion on Operative temperature control under Calculation options for more on this.

4

** Severe  ** Problem in interior solar distribution calculation (CHKBKS)

   **   ~~~   **    Solar Distribution = FullInteriorExterior will not work in Zone=42272

   **   ~~~   **    because vertex 6 of back surface=F_42272_10106_0_10277 is in front of receiving surface=W_42272_9_0_0

   **   ~~~   **    (Dot Product indicator=7.3314)

   **   ~~~   **    Check surface geometry; if OK, use Solar Distribution = FullExterior instead.

One or more zones is non-convex which makes the model incompatible with the 3-Full interior and exterior solar distribution algorithm. This error can also lead to temperature out of bounds errors.

5

** Severe  ** Temperature out of bounds (637.89) for surface=W_43311_4_0_0

   **   ~~~   ** in Zone=43276

   **   ~~~   **  Occurrence info=BRUSSELS - BEL IWEC DATA WMO#=064510, 01/04 13:30 - 13:32

   **   ~~~   ** A temperature out of bounds problem can be caused by several things.  The user

   **   ~~~   ** should check the weather environment, the level of internal gains with respect

   **   ~~~   ** to the zone, and the thermal properties of their materials among other things.

   **   ~~~   ** A common cause is a building with no thermal mass -- all materials with

   **   ~~~   ** Regular-R definitions.

The temperature of a surface has become too high/low, during the simulation. This error can be caused by highly glazed zones with holes taking up all or most of the floor. Some examples are double facade cavities, solar chimneys and atria-type zones. In some cases EnergyPlus isn't able to deal with such zones. The issue often isn't really overheating so much as instability in the solution - very low temperatures can result from the same situation. Here are some actions which have helped get round this problem in the past:

1. Make holes in the floor smaller. Bear in mind that with the default "Full exterior" solar distribution option, all solar gain is received by the floor, but if there is no floor due to a full-sized hole then a very large gain could be absorbed by a very small area of floor surface.
2. Avoid R-value (or other very low mass materials) on the inside surface of constructions.
3. It may be possible to use zone merging to combine zones which are being modelled individually separated by large holes. This can sometimes help to avoid the error.
4. Try switching off the Generate fully enclosed zones Advanced model option. This has helped in a few cases because the construction applied to surfaces used to fill in the gaps in zone geometry is low mass and has very high R-value which could cause a build-up of heat.

1

** Warning ** GetHTSubSurfaceData: A Multiplier > 1.0 for window/glass door W_67_4_0_0_0_0

**   ~~~   ** in conjunction with SolarDistribution = FullExterior or FullInteriorExterior

**   ~~~   ** can cause inaccurate shadowing on the window and/or

**   ~~~   ** inaccurate interior solar distribution from the window.

The Lump similar windows on surface model option has been selected which causes DesignBuilder to use the EnergyPlus Window Multiplier option to speed up simulations. The message is warning that the Window Multiplier option, when used in conjunction with the Full exterior or Full interior and exterior calculation options can lead to inaccurate distributions of solar radiation around the room.

2

** Warning ** GetSurfaceData:The total number of floors, walls, roofs and internal mass surfaces in Zone 59

**   ~~~   ** is < 6. This may cause an inaccurate zone heat balance calculation.

This warning is often generated for pitched roofs and for interior zones separated by virtual partitions and can safely be ignored.

3

** Warning ** GetGroundTemps: Some values for "GroundTemperatures" fall outside the range of 15-25C.

**   ~~~   ** These values may be inappropriate.  Please consult the Input Output Reference for more details.

The default ground temperatures used in DesignBuilder is 14degC. This may be inappropriate in some cases and EnergyPlus is warning about this. You should take care to enter realistic ground temperatures bearing in mind the advice given in the Ground Modelling section.

4

** Warning ** DXFOut: Could not triangulate surface="W_7469_0_0_1", type="Wall", check surface vertex order(entry)

Caused by a minor bug in EnergyPlus when creating a DXF representation of the model - it is not always able to fully triangulate all surfaces and generate a full set of surfaces. You can ignore the message for the purposes of simulation results.

5

** Warning ** Base surface does not surround subsurface (CHKSBS), Overlap Status=No-Overlap

**   ~~~   **   The base surround errors occurred 3 times.

**   ~~~   ** Surface "W_7376_3_0_0" misses SubSurface "W_7376_3_0_0_0_0"

These warnings are usually a reporting bug in EnergyPlus v2.0 and earlier.

6

** Warning ** Calculated design cooling/heating load for zone=78474 is zero.

**   ~~~   ** Check ZONE SIZING and ZONE CONTROL:THERMOSTATIC inputs.

Cooling/heating may have been switched off in this zone or there is no cooling/heating load (i.e. the zone does not require any cooling/heating).

7

For a zone sizing run, there must be at least 1 Zone Sizing object input.

Can usually be ignored.

8

 ** Severe  ** CAUTION -- Interzone surfaces are usually in different zones

   **   ~~~   ** Surface=F_59604_10071_0_10046, Zone=59604

   **   ~~~   ** Surface=C_72917_1_0_0, Zone=59604

This warning can be safely ignored. These messages can be prevented by switching on the Surfaces within zone treated as adiabatic option in Simulation Advanced Calculation Options

9

This warning will occur for partitions between 2 merged zones. Because of the merging, the zone is the same on both sides of the partition and EnergyPlus flags this as a potential mistake. To avoid this message, you can select the 'Surfaces within zone’ treated as adiabatic model option for Heating design, Cooling design and Simulation calculation options. In this case such partitions will instead be modelled using an adiabatic formulation where the ‘Outside face environment’ surface is the same as the actual surface and the warning is not generated. The warning can in any case be safely ignored.