During our recent session "Using IESVE for ASHRAE 90.1 Compliance", common themes emerged within the questions asked by attendees. To tackle these questions, we turned to Mithi Dave, Senior Business Development Manager at IES, and Girish RV, Business Head of our partner SCx Solutions.
Read on from invaluable advice from Mithi and Girish, on how IESVE can be utilised to design buildings to meet ASHRAE 90.1 requirements.
Which is the latest ASHRAE 90.1 version that can be used?
The VE currently supports up to the 2019 version of ASHRAE 90.1.
Can we do lighting control like daylight dimming?
Yes, you can apply this in the lighting control sections – daylight controls can be applied to sidelighting and toplighting; this can account for artificial lighting to be turned off or reduced. There is flexibility based on what room the controls are applied to, we would recommend grouping similar room types together when applying controls.
Regarding a fresh air system, are economizers and heat recovery possible?
Heat recovery is possible depending on the system you choose - you can define the latent load and the sensible load to consider the heat recovery.
ApacheHVAC has limited HVAC templates, how can we change these as required?
The Apache library has multiple predefined networks and systems, and we would encourage you to choose the one that best matches your requirements. Advanced users of ApacheHVAC can also modify the network to closely replicate the proposed design, however this comes with many hours of expertise.
Sometimes, clients design the exterior lighting higher than the LPD suggested by ASHRAE 90.1. What should be done in this scenario?
You can model for higher situations within the exterior lighting tab. Just enter the numbers you wish to use in the "proposed subtotal" column.
Where is the Building Performance Factor (BPF) taken from? How can we add custom BPF for a project?
By specifiying the building type in the project settings and choosing the correct climate zone as per the building location, the baseline system type and the applicable BPF value are determined (using ASHRAE 90.1 Table 4.2.1.1 as a reference).
You can create custom "u values" for thermal transmittance. These can be assigned to the building by going into “Custom Construction Type” under Envelope Thermo-physical properties, and double clicking on any room, which allows you to change the values assigned to each room.
How do we apply operating schedules and zoning?
Using the ASHRAE 90.1 Navigator, all the values and standards will be preselected to those that are expected for ASHRAE 90.1. If these values need changed, you can go into your Building Template Manager and cross check that all the automatically applied standards make sense for your building and change if necessary.
Are there any limitations of the software for process loads?
Process loads are application-specific energy uses that are modeled equally in baseline and proposed designs in ASHRAE 90.1, except when documented reductions are justified. While ASHRAE 90.1 does not mandate efficiency requirements for process loads, improvements can be credited via exceptional calculations in energy modeling.
For buildings with special features, such as a factory, data centre, or equipment lab, how can we model these whilst taking into consideration compliance to LEED, or any energy reduction credits? Which baseline should I use in that case?
For buildings with significant process loads, the Baseline Building Performance is typically modeled using ASHRAE 90.1, Appendix G, which defines baseline systems for standard building types. However, process loads (such as manufacturing equipment, server cooling, or lab-specific machinery) are modeled identically in both the baseline and proposed cases unless you apply the Exceptional Calculation Method (ECM) to justify reductions.
We would recommend the following guidelines for buildings like these:
Use ASHRAE 90.1 Appendix G for non-industrial portions, but treat process loads identically unless reductions are documented
Reference standards like ASHRAE 90.4 for specialized facilities (i.e. data centres)
Apply the Exceptional Calculation Method to justify energy savings in process loads with detailed documentation
Leverage high-efficiency systems, demand controls, and renewable energy to enhance overall energy performance and earn credits
Plug loads are the major consumption in total building energy consumption. Even though there are savings in lighting and HVAC energy by reducing the LPD and increase COP, the plug loads are major and identical between baseline and proposed. Considering plug loads minimize the total savings in energy between baseline and proposed, is there any solution for this?
Yes, plug loads can significantly impact total energy consumption and limit the savings between the baseline and proposed buildings. As a standard practice, plug loads are modeled as identical in baseline and proposed cases, and shall account for at least 25% of proposed energy consumption.
Plug loads are driven by occupant behaviour, equipment selection, and usage patterns, making it difficult to standardize baselines. Unlike lighting and HVAC, they are operational loads outside the control of building design and lack mandated efficiency standards. ASHRAE 90.1 simplifies energy modelling by treating plug loads identically in baseline and proposed cases, focusing on building-integrated systems with measurable design impacts.
Using IESVE for ASHRAE 90.1 Compliance
Missed our session on how IESVE can be utilised to meet the minimum design requirements for energy-efficient buildings, in line with the ASHRAE 90.1 standard? View the on-demand version to find out more.
Want to discover more about IESVE? Contact Mithi Dave for more information or visit our website.