ANSI/ASHRAE Standard 140

Our Building Assessment App has been tested against ANSI/ASHRAE Standard 140: building thermal envelope and fabric tests. ANSI/ASHRAE Standard 140 test cases were undertaken, with results compared with results from other whole building energy analysis programs.

Comparative tests show that Speckel and EnergyPlus Version 9.5.0 and 22.2 are reasonable and within limits set compared to other energy simulation programs. Therefore, Speckel meets the ANSI/ASHRAE Standard 140 requirements for building thermal envelope and fabric tests.

ANSI/ASHRAE Standard 140 Test Cases

The tests described in Section 5.2 of ANSI/ASHRAE Standard 140 were performed. Standard 140 is a standard method of test that can be used for identifying and diagnosing predictive differences from whole-building energy simulation software that algorithmic differences, modelling limitations, input differences, or coding errors may possibly cause.

The following tests were performed as specified within the modelling notes:

  • Case 600 – Base Case Low Mass Building

  • Case 610 – South Shading Test for Low Mass Building

  • Case 620 – East/West Window Orientation Test for Low-Mass Building

  • Case 630 – East/West Shading Test for Low Mass Building

  • Case 900 –Base Case High Mass Building

  • Case 910 –South Shading Test for High Mass Building

  • Case 920 – East/West Window Orientation Test for High Mass Building

  • Case 930 – East/West Shading Test for High Mass Building

Case 600 – Base Case Low Mass Building

The basic test building (Figure 1) is a rectangular single zone (8 m wide x 6 m long x 2.7 m high) with no interior partitions (removed) and 12 m2 of windows on the south exposure. The building is of lightweight construction with characteristics as described below. For further details, refer to Section 5.2.1 of ANSI/ASHRAE Standard 140.

Case 610 – South Shading Test for Low Mass Building

Case 610 uses the Base Building modelled in Case 600 and adds a 1 m horizontal overhang across the entire length of the south wall over the south-facing windows at the roof level. All other characteristics of the building were identical to the Base Case building. This case tests the ability of a program to treat the shading of a south-exposed window.

Case 620 – East/West Window Orientation Test for Low-Mass Building

Case 620 uses the Base Building modelled in Case 600 with the following changes: The window orientation was modified to add 6 m2 of window area to both the east and west walls. The window properties are the same as in Case 600. The south windows were eliminated and replaced with the wall construction used throughout the building.

Case 630 – East/West Shading Test for Low Mass Building

Case 630 is the same as Case 620 except that a shade overhang and shade fins were added around the east and west window. A 1 m horizontal overhang is located at the roof level and extends across the 3 m width of each window. The 1 m wide right and left vertical shade fins are located on the edge of each window and extend from the roof down to the ground.

Case 900 –Base Case High Mass Building

The 900 series of tests use the same building model used for the 600 tests, except that the wall and floor construction was changed to use heavier materials. Everything else with the building remained the same.

Case 910 –South Shading Test for High Mass Building

Case 910 uses the high mass Base Building modelled in Case 900, except that a 1 m horizontal overhang was added to the entire length of the south wall over the south-facing windows at the roof level. See Figure 2. All other building characteristics were identical to the high-mass Base Building of Case 900. This case tests the ability of a program to treat the shading of a south-exposed window. This case is identical to Case 610 except for high-mass walls and floor.

Case 920 – East/West Window Orientation Test for High Mass Building

Case 920 is identical to Case 620 except for high-mass walls and floor.

Case 930 – East/West Shading Test for High Mass Building

Case 930 is identical to Case 630 except for high-mass walls and floor.

Modelling Results

Results for all cases of low and high mass are presented below. All comparative tests show that Speckel and EnergyPlus Version 9.5.0 are reasonable compared to other energy simulation programs. Therefore, Speckel meets the ANSI/ASHRAE Standard 140-2011 requirements. All results files are available upon request.

Modelling Assumptions

The following assumptions have been assumed on all test cases.

EnergyplusVersion 9.5.0

Terrain

Country

Loads Convergence Tolerance Value

0.04

Temp Convergence Tolerance Value

0.4

Solar Distribution

Full Interior and Exterior

Max Warmup Days

25

Min Warmup Dyas

1

Shading Calculation Method

Timestep

Shading Calculation Frequency

1

Surface Convection Algorithm: Inside

TARP= variable natural convection based on the temperature difference

Surface Convection Algorithm: Outside

DOE-2 = correlation from measurements by Klems and Yazdanian for rough surfaces

Timestep

4

Run Period

1 year

Site Ground Temps

10 degrees C

Site Ground Reflectance

0.20

Internal Loads

4.16 W/m2

Zone Infiltration

0.5 ACH

HVAC Setpoints

21 degrees C / 27 degrees C

HVAC Template

Ideal Loads Air Systems

Material Assumptions

For all materials, visible and solar absorptance has been set at 0.6. Thermal absorptance is set at 0.9. All units are in imperial.

Wall Construction (lightweight mass)

Roof Construction (lightweight mass)

Floor Construction (lightweight mass)

Window Properties - Only U-value, SHGC and VLT have been used.

Wall Construction (heavyweight mass)

Floor Construction (heavyweight mass)

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