ASHRAE Building Energy Quotient (Building EQ) Website

ASHRAE Building Energy Quotient (Building EQ) Website

ASHRAE’s Building EQ Web Portal provides a quick energy analysis that benchmarks a building’s energy performance. Building EQ assists in the preparation of an ASHRAE Level 1 Energy Audit to identify means to improve a building’s energy performance including low-cost, no-cost energy efficiency measures and an Indoor Environmental Quality (IEQ) survey with recorded measurements to provide additional information to assess a building’s performance.

Two different evaluations can be used independently to compare a candidate building to other similar buildings in the same climate zone or together for an assessment of a building’s design potential compared to actual operation:

In Operation compares actual building energy use based on metered energy information.

As Designed compares potential energy use based on the building’s physical characteristics and systems with standardized energy use simulation.

The Old Way

When Building EQ was first introduced, building owners and engineers could submit information about their candidate building to ASHRAE using an Excel spreadsheet template. This was a very inefficient way of doing things. It involved filling out the required data into a spreadsheet, and then uploading the spreadsheet(s) to the ASHRAE Building EQ website. Then, ASHRAE personnel would open the spreadsheet and determine whether the data was valid, and if it was, what rating to assign the building. The spreadsheet method was wrought with many inefficiencies including:

  1. If data was missing or invalid, the spreadsheet would be sent back to the building owner to be corrected. This involved working with multiple versions of the spreadsheet which could very quickly become confusing and could potentially result in working with outdated and incorrect data.
  2. ASHRAE personnel would validate all of the data manually, which was a slow and inaccurate process.
  3. There were no links within the spreadsheet to ENERGY STAR Portfolio Manager that would allow users to migrate data to/from other programs into bEQ.
  4. The spreadsheet was only in IP units.
  5. Many more inefficiencies too numerous to list here

The New Web Portal

In 2016, Carmel Software was hired to develop the web-based user interface that would solve all of the problems above and introduce even more efficiencies and features that a spreadsheet could never provide. In addition, Carmel has tasked to develop a website that would be able to accommodate many types of connected devices including Windows and Mac desktops/laptops, all iOS and Android mobile smartphones and tablets. After about 9 months of development, the ASHRAE Building EQ portal was officially launched, and it has been a resounding success. More project submissions were made within the first 2 months of the website launch than within the first 5 years of existence of the Building EQ rating system with only spreadsheet submissions. As of November 2019, over 500 projects have been submitted.

What Does Building EQ Measure?

The Building EQ rating system rates building energy usage only. It is not meant to compete with LEED which measures far more including water usage, material sourcing, and much more. The Building EQ rating system works as follows:

  1. Based upon the building type, climate zone, and heating and cooling degree days, a lookup for a benchmark value is performed using an ASHRAE Standard 100 site median table derived from CBECS (Commercial Building Energy Consumption Survey) 2012 building energy usage data. This usage data is expressed in units of energy use intensity (EUI)  which is the amount of energy used per square foot per year.
  2. The user then enters a year’s worth of utility data and the total square footage of the building to calculate the specific building’s EUI. This building-specific EUI is compared with the normalized benchmark EUI  and a Building EQ score is derived by dividing the two numbers then multiplying by 100. The range of the score is from 0 to 200 where 0 is the most energy efficient and 200 is the least. A score below 100 is considered energy efficient since the specific building beats the benchmark EUI derived from CBECS.

Additional Inputs

There are many additional inputs in the ASHRAE Building EQ web portal above and beyond those that are used to calculate the Building EQ score. Below is a list of these additional inputs for the In Operation method:

Building Performance Credentials

The “Building Performance Credentials” section allows the user to input any other ratings or scores the building may have received including Energy Star, LEED, Green Globes, and more.

Building Performance Chars

IEQ Screening

The “Indoor Environmental Quality Screening” tab includes a number of accordions (sections) that allow the user to input additional information about the building.

The objective of the building indoor environmental quality (IEQ) screening is to verify that the IEQ of the building as it affects the occupants has not been obviously compromised in the pursuit of energy efficiency and energy savings. The screening is intended to go beyond professional judgment with the inclusion of actual measurements. The measurements are focused on areas identified in the screening and are therefore representative of the building spaces and not intended to be all inclusive. If no issues are identified, the Assessor should take representative spot measurements throughout the building in order to provide feedback to the building owner/operator. Representative space types may be determined by space type (office, conference room, corridor), by space usage (different tenants or floors), or by space system type (building served by multiple system types). The information is provided to the building operator for follow-up actions and to benchmark, evaluate, and diagnosis building systems that affect indoor environmental quality including thermal comfort, lighting quality, and ventilation for indoor air quality. The IEQ screening is not intended to serve in the place of a full IEQ evaluation performed by an expert in that field. For this reason, it is important that the building owner follow up separately on any deficiency or potential problem noted on the forms by having a full IEQ evaluation performed by a qualified professional.

Indoor Environmental Quality

Energy Efficiency Measures (EEMs)

This tab allows the user to input any energy efficiency or conservation measures that have been implemented. The measures are divided by category: Building Envelope, Lighting, HVAC, Refrigeration, Energy Generation/Distribution, Other). Within each accordion is a drop down with a list of pre-populated measures.  These measures are outlined in Informative Annex D and Informative Annex E of ASHRAE Standard 100-2015. The measures are divided by category: Building Envelope, Lighting, HVAC, Refrigeration, Energy Generation/Distribution, Other).

Building EQ EEM Categories

The user is also able to enter a cost range and payback period for each measure.

There are 3 additional inputs in each accordion that allow the user to input their own custom measure descriptions along with cost ranges and payback periods.

Building EQ Example EEM

Photos and Attachments

This final tab allows users to add photos and attachments along with descriptions and categories. These photos will appear in the narrative report.

Building EQ Photo Tab

Building EQ Reporting

Standard 211 Audit Spreadsheet

Building EQ does something else that no other rating system does: It works closely with ASHRAE Standard 211 – Standard for Commercial Building Energy Audits. This is an ANSI standard that formalizes the process of performing building energy audits. ASHRAE Standard 211 protects a building owner/operator’s energy audit investment by providing an outline for auditors and offering best practices that ensure quality audits. It sets forth requirements for the experience and credentials of energy auditors, specifications for compliance and clear definitions of the audit processes and scope.

A Standard 211 audit spreadsheet is included along with the actual text of the standard. This spreadsheet allows users to fill in all information related to Level 1 and Level 2 energy audits.

Remember, the primary function of an energy audit is to identify all of the energy streams in a facility in order to balance total energy input with energy use. The ASHRAE Level 1 is a simple and quick audit that requires a brief review of building operating characteristics. It mainly identifies low-cost/no-cost measures and will only uncover major problem areas. Level 1 audits are a great way to prioritize energy efficiency projects and to assess the need for a more detailed audit. The ASHRAE Level 2 audit includes the Level 1 audit plus more detailed energy calculations and life cycle cost analysis of proposed energy efficiency measures. This type of audit identifies all energy conservation measures appropriate for the facility given its operating parameters. 

Much of the information required to fill out the Level 1 inputs in the audit spreadsheet are already inputted into the ASHRAE Building EQ web portal. Therefore, the portal allows the user (for a fee) to create a Standard 211 spreadsheet with many of the Level 1 inputs pre-populated. Even though the spreadsheet also includes Level 2 parameters, Building EQ does not include most of the information required for Level 2 audits. Therefore, this information needs to be manually filled in.

Below is a screenshot of one of the tabs in the Standard 211 Excel spreadsheet:

ASHRAE Standard 211 spreadsheet

ASHRAE Building EQ Label

Once a Building EQ project is approved by ASHRAE personnel, the user is able to print out a Building EQ label that includes the Building EQ logo along with a sliding scale showing the final Building EQ score. The following is an example of the Building EQ label:

Building EQ Label

Building EQ Energy Audit Narrative Report

This Microsoft Word doc report provides a template for an ASHRAE Level 1 Energy Audit that follows the information in Section 6 (Reporting), Annex C (Reporting Forms), and Annex D (Report Outlines) in ASHRAE Standard 211.  The template provides recommended text and boiler plate language to assist the user in preparing a comprehensive report and is automatically populated with information collected and entered into the Building EQ Portal as part of the Building EQ In Operation assessment process. The recommended text can be edited as needed by the user. The audit specific information populated from the Building EQ Portal is shown in filled-in tables in the report. Below is an example of two pages of the report:

ASHRAE Building EQ Narrative Report

Additional Functionality

The Building EQ portal includes additional functionality that helps expand its usefulness:

Integration with Energy Star EUI Data

Depending upon the building type that the user selects, the energy utilization index (EUI) data will either be pulled from ASHRAE Standard 100 database in Building EQ or from an Energy Star service hosted by Architecture 2030 Zero-Tool. Each Energy Star building type has a different set of parameters associated with it so the user will be prompted to input many different types of values. Once the user has inputted all of the required information, pressing the “Get EUI Values” button calls a remote calculation engine that retrieves the appropriate Energy Star EUI value based upon the building type and parameter inputs.

Energy Star

Integration with Energy Star Portfolio Manager

For electricity, natural gas, and other “non-delivered” fuel types, the user can import utility data that already exists in Energy Star’s Portfolio Manager software. All the user needs to do is export the utility data from a PM project to a .csv file. Then, import the .csv file into the appropriate fuel type. The data should be monthly for one year taken within the past 18 months.

Building EQ Utility Data

Integration with BuildingSync

BuildingSync® is a common schema for energy audit data that can be utilized by different software and databases involved in the energy audit process. It allows data to be more easily aggregated, compared, and exchanged between different databases and software tools. This streamlines the energy audit process, improving the value of the data, minimizing duplication of effort for subsequent audits, and facilitating achievement of greater energy efficiency.

Several tools utilize BuildingSync including U.S. Department of Energy’s Building Energy Asset Score. Asset Score is a national standardized tool for assessing the physical and structural energy efficiency of commercial and multifamily residential buildings. The Asset Score generates a simple energy efficiency rating that enables comparison among buildings, and identifies opportunities to invest in energy efficiency upgrades. Data exported from Asset Score (specifically Audit Template) via BuildingSync can be imported into BuildingEQ to populate relevant (but not all) data.

Building EQ Audit Template

Latest Stats

The following are the latest stats as of December 1, 2019:

Number of users: 998

Number of projects: 627

Average area of buildings analyzed: 69,392 sqft

To sign up for a free account, click here.

A Progress Report on gbXML Validation Efforts

A Progress Report on gbXML Validation Efforts


Carmel Software was hired by the National Renewable Energy Lab (NREL) to update and improve the Green Building XML ( schema, all in the name of improving interoperability amongst disparate building design software tools. This progress report summarizes the work completed over the past year.

Overall Goal and Objectives

The goal of this project was to validate the National Renewable Energy Lab’s (NREL’s) OpenStudio software tool to produce valid gbXML and also set the stage to validate other BIM and building analysis software tools in the future. There were three main objectives of this validation work.

  1. The first objective was to demonstrate that the OpenStudio software could pass the gbXML validation procedure.
  2. The second objective was to encourage other software vendors to certify their software using the validation procedure as well.
  3. The third objective was to work towards a generic validator that could be used on general user models, as opposed to the strict test case models required by the gbXML validation procedure. Delivering a fully working validator was out of scope of this work, therefore requirements were developed to set the stage for future work.

In support of the first objective, we developed OpenStudio models which represented the buildings in the validation procedure test case. These models were generated programmatically using the OpenStudio Ruby Application Programming Interface (API) to reduce maintenance costs and to allow them to be leveraged for other purposes. OpenStudio passed the validation procedures and is now the first software authoring tool to officially become “gbXML certified” ( ).

In support of the second objective, we drastically improved the validation website, documentation, and tools required to apply the validation procedure. We publicized the validation procedure and encouraged gbXML software vendors to apply it to their tools. This required contacting other gbXML software vendors directly as well as making public announcements, conducting live webinars, and promoting other ways to generate user interest in the validation efforts. We publicized the state of the OpenStudio validation efforts to encourage other software tools to apply the validation procedure to their own tools. In addition, we simplified and streamlined the validation process to allow the process to be both more responsive and clear to market demands, while also allowing room for future growth of test cases. In fact, Autodesk will soon be validated to Level 2 compliance (see below) and is working with on Level 3 compliance.

In support of the third objective, we developed requirements for a generic validator. User stories were developed and preliminary mockups were made. The most important user story developed was to allow a user to upload their gbXML file to the website and view a 3D representation in their web browser. This would allow the user to identify any problems with their model visually. The second use case was for software to detect certain classes of problems with the user’s model and identify those visually in the 3D display. Finally, the use case of upgrading user models to the current gbXML schema version was identified.


Here are the tasks that were performed to achieve the above objectives:

  1. Developed OpenStudio Models for Validation Procedure
    We developed OpenStudio models for a number of the buildings in the validation procedure test suite. The test cases were derived from the ASHRAE RP-1468 documentation. The models were programmatically generated using the OpenStudio Ruby API. All scripts and model content developed for this purpose were developed under the Lesser General Public License (LGPL) open source license and are maintained in a public repository on ( ).
  2. Validated OpenStudio gbXML Export/Import
    We applied validation procedures to each of the OpenStudio models developed in task 1. We verified that each of the validation test cases imported correctly into the OpenStudio SketchUp plug-in. We also addressed any issues with the validation software that were found in this work. For example, the OpenStudio validation forced to address geometry created by thin-walled geometries, and metric-only software. Previous versions of the validator only addressed thick-walled geometry engines, and supported IP-units. The validation process and OpenStudio were made more robust as a result of this process.

    Highlights of improvements/fixes to OpenStudio as a result of this project:
    • correctly specifies SlabOnGrade elements
    • correctly handles area calculations of sloping floors and ceilings (before calculated area as zero)
    • handles most second-level space boundary translations, automatically, for simple geometries
    • gbXML export up-to-date with version 6.01 of gbXML

    Highlights of improvements/fixes to gbXML validation as a result of this process:
    • unit of measure handling
    • special procedure development for thin-walled geometry creators, opening up validation to a wider audience
    • improved validation website user interface and user experience
    • better error-handling and user messaging when validation fails
    • improved geometry validation engine

  3. Improved Validation Website and Documentation
    The previous validation website was not hosted on the domain which reduced its visibility and credibility. For this task, we moved the website to a hosting platform that supports the validator software. The website was redesigned to more prominently display the validation procedure and documentation. The website now shows which software tools have been validated or are in the process of being validated. See for more details.
  4. Promoted gbXML Validation Efforts
    This task was performed in parallel with other tasks listed above; the purpose was to keep other software vendors and the public up to date on gbXML validation efforts. We attended the four day SimBuild 2016 Conference in Salt Lake City in August 2016 to promote gbXML validation efforts. In addition, we conducted two live webinars to explain our work.
  5. Generic Validator
    Delivering a fully functional generic validator was out of scope for this work. Therefore, work on this area was focused on developing user stories and requirements for future work. The most important user story developed was to allow a user to upload their gbXML file to the website and view a 3D representation in their web browser. This would allow the user to identify any problems with their model visually. The second use case was for software to detect certain classes of problems with the user’s model and identify those visually in the 3D display. Finally, the use case of upgrading user models to the current gbXML schema version was identified.

    Integration with the Autodesk Forge API was investigated as a potential solution for viewing user submitted 3D models. However, this is still a work-in-progress since the Forge API is in beta phase.

Significant Findings and Issues

During this project, we decided that 3 levels of gbXML certification, or compliance, were required to provide more clarity to the community of users and vendors.:

  1. Level 1 compliance involves validating that a gbXML file is a well formed XML (per the W3C ISO Standard) and also conforms to the gbXML XSD (from gbXML versions 0.37 to 6.01, depending upon which version the software tool currently exports).
  2. Level 2 compliance involves validating a gbXML file against 8 to 10 geometric “test-cases” that are based upon ASHRAE Research Project 1468, “Development of a Reference Building Information Model (BIM) for Thermal Model Compliance Testing”. Level 2 requires that second level space boundaries be correct for the simplest test cases, and pass a small subset of translation edge cases.
  3. Level 3 compliance has yet to be fully defined. However, Level 3 does involve certain levels of vendor tool automation that goes far above and beyond Levels 1 and 2 compliance. We are currently working with Autodesk to better define Level 3 compliance (See the Future Work section for more details).

List of Issues

OpenStudio passed the following test cases:

  1. Test Case 3: Test for proper second level space boundary representation
  2. Test Case 6: Test for proper second level space boundary representation
  3. Test Case 7: Test for basic pitched roof representation
  4. Test Case 8: Test for basic sloped slab on grade representation
  5. Test Case 12: Test for proper second level space boundary representation
  6. Basic Whole Building Test Case 1: Test for proper second level space boundary representation

To pass these test cases, it did require that NREL make some updates to the OpenStudio SDK responsible for gbXML export since there were a few errors that were pervasive for every test case. Therefore, NREL needed to make some changes to the gbXML export feature of OpenStudio to be compliant with the validation process. gbXML provided NREL with guidance as to how each XML file should look in order to pass, which NREL took and made changes to their code base. In some cases, gbXML decided to relax configurable constraints, to allow the document to pass.
Below is the full list of issues and changes to the OpenStudio code base made as a result of this work effort:

  1. There were no BuildingStorey definitions in any export from OpenStudio. This is a required element, but we relaxed this for validation purposes.
  2. The Building->Area calculation that was done during export did not meet gbXML specifications for the Building Area calculation. To be fair, gbXML may not have the tightest definition in terms of the criteria for when a Space Area is included in the Building Area, but the point is, plenums and other non-occupiable spaces shouldn’t be included in the building area calculation.
  3. Any time there was a floor that was on-grade (industry standard is when z=0, and it seems OpenStudio follows this convention) we would expect the surfaceTypeEnum for that surface to be SlabOnGrade, but OpenStudio defines these surfaces as UndergroundFloor. This needed to be changed.
  4. Thin-Shelled geometry challenges: The fact that OpenStudio makes gbXML derived from a thin-walled geometry paradigm consistent with the building energy modeling paradigm as opposed to a BIM model posed a basic philosophical challenge for the validation process. Originally, the validator was designed for BIM-centric tools that have wall thicknesses inherent in the modeling environment. Autodesk Revit, for example, assumes that the wall thicknesses affect the volume and area calculations, even though the wall vertices go to the centerline of the thickness (as if the walls had no thickness at all). When we tried to use these same standard test files as a comparison point for a gbXML created via OpenStudio, we encountered an issue. Whereas we modeled the walls in OpenStudio as if they were on the centerline, with the same coordinates as the standard files, now the volume and area calculations came out differently than the standard files. Of course, if we tried changing things around and modeled the surfaces in OpenStudio at the inner wetted perimeter, we get the volume and area correct, but now the polygon coordinates are in a different location and don’t match the standard file PolyLoop coordinates. So either way, it is not a perfect process.
  5. Changes to the validator code base: We made several improvements to the validation engine itself, and also to the standard test case XML files as a result of this work that has already been incorporated into the latest version of the validator. We found two problems with the standard test case files: Occasionally, there were still errors in the files that should no longer persist by the end of this process. The whole building test cases, made at the end of phase two, were particularly problematic because we made them with Honeybee out of Grasshopper. Secondly, sometimes the decimal precision was pretty extreme because for all the other test cases we used Revit in US-IP units to create the test cases originally. This meant for sloping surfaces, there was sometimes units like 9’10-11/16” that made for some difficulties when re-creating the test cases. We tightened these up so for a majority of the test cases there was much less guess-work and complexities around the units of measure.

Future Work – New gbXML Features

Further Develop Level 3 Compliance
We will be working with Autodesk to achieve Level 3 certification, which has yet to be fully defined. It does involve certain levels of vendor tool automation that goes far above and beyond Levels 1 and 2 compliance. Autodesk desires to achieve Level 3 compliance for both Autodesk Revit and Insight 360. Some examples of Autodesk-specific Level 3 automation include:

  1. Handling ‘real’ architectural models i.e. supporting a very wide variety of modeling practices, coping with natural inaccuracies (small gaps / overlaps) and scaling from concept to detailed design
  2. Automatic perimeter / core thermal zoning
  3. Automatic identification of elements acting as shading (as opposed to room bounding) without manual definition
  4. Handling ‘Sandwich’ conditions i.e. when two or more elements are adjacent or very closely adjacent and often not perfectly parallel but essentially a single gbXML surface
  5. Definition of material thermal properties (which get very interesting when combined with sandwich conditions)
  6. Working with or with explicit room/space objects and their associate metadata
  7. Above / below grade
  8. Columns
  9. Openings
  10. Ceiling voids

Discuss the possibility of “use case” based validation. For example, what fields are required for the energy modeling use case (or maybe the OpenStudio use case)? What fields are required for the HVAC loads use case? See for an example of this.

Develop a gbXML Conversion Tool
Both NREL and Autodesk have requested that we develop a simple software tool (web-based) that converts previous versions of gbXML (i.e. – 0.37) to later or the current versions since major tools such as Autodesk Revit continue to support the 0.37 version while validation only supports the latest version. This is not an easy task on the part of the software vendor to update to the latest version since tools like Autodesk Revit have long-term “wish-list to release cycles” (often 1 or more years). Therefore, developing a conversion tool will allow these previous versions of gbXML to update to later versions.

Develop a Generic Validator and Open-Source Geometry Engine

While we have successfully developed a test-case validation tool ( ), we still need to develop a “generic” validation software tool that can be used by more stakeholders including energy modelers, engineers, architects, and others. This tool should be able to validate any generic gbXML, not just test-case gbXML files. We believe we are closer than ever to achieving this vision, however, there is limited time and budget to test such concepts. Developing unit tests, and making incremental improvements to this code base, is a full-time effort that is constantly in need of development efforts.
The software development effort taken thus far to develop vendor certification tools will be leveraged for the generic validator, one that can accept any user model. A web page shall be developed on so a user can upload their gbXML model and the validator shall determine if there are any defects. If there are defects, the website shall provide information to alert the user to any defects that were found. A web based 3D visualization tool may be provided to visualize the uploaded model and to identify the defects in a meaningful way. We plan on using Autodesk’s Forge Viewer API to translate the gbXML geometry into a web-based model.

Create a gbXML Portal and Accompanying Web Service

Along with the generic validator wish-list item above, another long-time goal has been to create a gbXML “portal” that allows users to register and upload gbXML files for remote storage. We would create a web service (or web API) that could be accessed by authorized software tools to import and/or export gbXML files to and from this portal. This would provide the following benefits:

  1. Different “dot” versions of gbXML could automatically be converted to the appropriate “dot” gbXML version that is supported by a consuming software tool.
  2. Different versions of the same gbXML file that is produced by a BIM authoring tool could be stored in the portal so that a consuming tool could easily re-import it and update any changed information. Think of it as a sort of “version control” function.
  3. If enough gbXML files are uploaded to the portal, we could begin to analyze the data and look for trends that may benefit the industry. For example, information from the uploaded models could be analyzed so as to gain insight on the use of gbXML in practice, e.g. which software tool authored the model and which defects were found.

The Art and Science of Psychrometrics

The Art and Science of Psychrometrics


I recently hosted an ASHRAE-sponsored webinar that discussed the
basics of psychrometrics and also included a demo of the ASHRAE
Psychrometric Chart iPad app
(which we designed). I was amazed that
almost 900 people registered for this webinar. This tells me that there
is keen interest in understanding psychrometrics and also finding ways
to more easily perform psychrometric calculations.


The following are links to both the webinar recording and a PDF of the PowerPoint slide deck:

  • Click here to view a recording of the webinar.
  • Click here to download a PDF of the PowerPoint slide deck.

This webinar included an overview of the science behind psychrometrics. Then, I
demo’d the app by creating sample HVAC processes. This webinar
could have easily gone on for two hours, but I was limited to one.
I will split this topic into 2 separate blog postings. This month’s posting will
talk about the basics of psychrometrics. A follow-up blog posting will
show 10 example HVAC processes using the psych chart app.

Importance of Psychrometrics

study and understanding of psychrometrics is so important for helping engineers to
design HVAC systems for all types of applications and situations including:

It’s vital for human comfort since it’s difficult to work when the conditions are too
humid or too dry. The following slide displays the comfort zone for humans:


systems designed for controlling the environment (temperature, humidity and
pollutants) within a museum, a library, or any type of archival facility is much more complex than the system
designed simply for maintaining human comfort. This system is designed to
control the environment for the preservation of highly valuable artifacts or
works of art. These HVAC systems must be operational 24/7 and often
require redundancy.

Hospital ORs are kept so cold that there is always risk of condensation
the ceiling since the temperature often goes below the dew point of
ambient conditions (it’s called “raining in the OR”). Therefore, using
psychrometrics, it’s possible to determine the proper humidity ratio of the
air so as to eliminate condensation.

4. Many
industrial and manufacturing companies use chilled water to remove heat from
various manufacturing processes. As the air or process is cooled below the
ambient dew point, condensation can occur. Desiccant dehumidifiers can
eliminate this condensation. This results in a higher quality part and reduced
cycle time, allowing manufactured parts to be produced faster.

Is it Art or is it Science?

If you take the equations from the ASHRAE Handbook of Fundamentals seen below and
create a visual representation of those equations, it becomes a powerful tool for HVAC design.


You create this visually appealing chart that
allows you to plot simple and complex HVAC processes and actually visualize
them. Even those outside the
industry can begin to understand what the ratios of air to water mean and how
HVAC systems alter those ratios for the benefit of human comfort.


Definition of Psychrometrics

A psychrometric chart is a graph of the thermodynamic
parameters of moist air at a constant elevation or barometric pressure. The genius
behind this chart is that it allows HVAC professionals to visualize all types
of HVAC processes for cooling, heating, humidification, dehumidification and
much more.

a chart at 0 feet elevation:


a chart at 12,000 feet elevation. It looks a bit different than the 0 elevation


psychrometric software for desktop or mobile, most engineers had to resort to using the
0 elevation chart even if they were designing a building in, say, Denver
which is 5000 ft
elevation. This produces inaccurate results because the density of air is so
different between 0 and 5000 feet. As you can see, the elevation change drastically changes the
shape of the graph.

The Components of the Psychrometric Chart

The following is a list of the components that make up a psychrometric chart:


Dry bulb temperature: The
temperature of air as registered by an ordinary thermometer

Absolute humidity or moisture
weight of water vapor in grains or pounds of moisture per pound of dry air or grams of
water vapor per kg of air, i.e. g/kg. It is also known as moisture content or humidity

Wet bulb temperature: The
temperature registered by a thermometer whose bulb is covered by a wetted wick and exposed to a
current of rapidly moving air (sling psychrometer)

Enthalpy: A
thermal property indicating the quantity of heat in the air above an arbitrary datum, in Btu per pound of dry air. The
datum for dry air is 0 deg F
and, for the moisture content
32 deg F water.

Specific volume: The
cubic feet of the mixture per pound of dry air or cubic meter of the mixture per kg of dry air represented in
m3/kg. It is the reciprocal of density. (1 over the density)

Relative humidity: RH is
an expression of the moisture content of a given atmosphere as a percentage of the saturation humidity
at the same temperature. Most everyone uses this # to communicate how humid it
is out: 50% humidity.

Dew point temperature: The
temperature at which condensation of moisture begins when the air is cooled. The best example of
this is a cold glass of water. If the temp. of the water is less than the dewpoint of
the ambient conditions, then you will see condensation on the outside of the

SHR protractor: Allows the user to draw
the SHR line which is discussed later.

Other Psychrometric Terms


Saturation curve: This is where the air
is 100% saturated no matter what the DB and WB
temperatures are. Along this curve, the DB, WB, and DP are all the same at any
1 point.

ADP: Apparatus dew point (ADP) is the coil
surface dew point temperature required to accomplish a cooling/dehumidifying
process. As you can see from this simple psych drawing, the air entering the
coil is cooled to slightly less than 100% saturation. If you want to extract
water out of the air (dehumidify), then you need to approach the ADP which does
exactly that.

Bypass factor: Some
of the air flowing through the coil impinges on the water tubes or the fins and
is cooled to the ADP. Other air passes through unchanged.

SHR: The ratio of space sensible cooling
to total cooling is useful for plotting the slope
of the path that supply air travels after
introduction into the space.

Adiabatic cooling: This is also called
evaporative cooling or constant-enthalpy
cooling. Adiabatic
cooling is
the process of reducing heat through a change in air pressure caused by volume
expansion. It’s also called free
cooling since the sensible heat is being converted to latent heat without the
help of mechanical DX cooling.

Simple Psychrometric Processes


Sensible heating/cooling involves the increase or decrease in the
temperature of air without changing its humidity ratio. Example: passing moist
air over a room space heater.

Humidification/dehumidification involves the increase or decrease in the
humidity ratio of air without changing its dry bulb temperature.

Heating and humidifying involves the
simultaneous increase in both the dry bulb temperature and humidity ratio of the air.

Cooling and dehumidifying involves
the removal of water from the air as the air temperature falls below the dew-point temperature.

the cooling of air without heat loss or gain. Sensible heat lost by the air is
converted to latent heat in the added water vapor. Also called “Free cooling”.

Chemical dehumidification or adiabatic dehumidification is
accomplished by passing air through a chemical absorbent like silica gel. Some of the moisture is removed and the latent
heat of evaporation is released. There will be an increase in sensible heat
content and along the enthalpy line.

Complex Processes


Complex psychrometric process include a combination of the
simple processes discussed above. I will touch upon these complex processes in next month’s blog that will include up to 10 examples of complex psychrometric processes.

Click the following image to download the app:


Stay tuned for next month where I will describe 10 psychrometric use cases ranging from simple cooling to complex combo indirect/direct dehumidification and cooling.

Green Building XML (gbXML) Certification

Green Building XML (gbXML) Certification

Carmel Software is a member of the Board of Directors of which houses the Green Building XML open schema. This schema helps facilitate the transfer of building properties stored in 3D building information models (BIM) to engineering analysis tools, all in the name of designing more energy efficient buildings.

For example, an architect who is designing a building using a BIM tool such as Autodesk Revit is able to not only create the building geometry, but also assign properties to the building including lighting density, occupancy hours, wall and window properties, and much more. All of this information can be exported (or “saved-as”) as gbXML file that is then imported into a software analysis tool that predicts yearly building energy usage (such as Trane TRACE). The purpose of this integration is to eliminate the need to enter the same information into the analysis tool that is already available in the BIM tool.

It has proven so popular that almost 40 software tools world-wide have some type of gbXML integration. Click here for the list.

Recently, we have been funded by the US Department of Energy and National Renewable Energy Lab (NREL) to develop a suite of “test cases” that software vendors will need to undergo to become certified in gbXML. Certification is a process that gives vendors who produce gbXML a stamp of approval from


Achieving Certification

How does a vendor achieve certification? has developed a series of test cases (in fact, just really simple building shapes) that each pose a new situation for the vendor to adhere to. In other words, the vendor is responsible for recreating a simple building shape in their own software tool. Then, they “save-as” gbXML and upload it to our validator software. If the building shape closely matches the test case gbXML file, then it “passes”:


What is being tested? For each test case, there are a number of items being “tested”, and it is all focused on geometry:

  1. Are
    all the surfaces in the right location and orientation?
  2. Are
    all the surfaces properly defined?  Walls
    are walls, floors are floors, interior/exterior etc. ?
  3. Is
    the gbXML “good”? i.e. – No typos, incorrect names, missing


Example Test Cases

Test Case 2: A window test case (see image below)

  1. Single
    window is drawn
  2. User
    converts to gbXML
  3. Two
    windows are created
  4. Overhang
    is linked to both windows.


Test Case 3: A test case for spatial configuration. If a tool was to submit for compliance, but is not touting its automated capaibilities, then the wall types would be declared explicitly and exported to gbXML and submitted for compliance.

If a tool was to submit for compliance, but is advertising automated capabilities, then the wall types would not need to be called out, and the translation to a thermal representation of the building in gbXML would happen automatically:


Test Case 5: Here is an example of a test case (see image below):

  1. Single
    volume is drawn
  2. User
    converts to gbXML
  3. Walls
    automatically separated
  4. gbXML
    shows 8 walls (4 above and below grade)


Test Case 6: If a tool was to submit for compliance, not touting automated capabilities, then the wall types would be declared explicitly, and then exported to gbXML and submitted for compliance.

If a tool was to submit for compliance, but is advertising automated capabilities, then the wall types would not need to be called out, and the translation to a thermal representation of the building in gbXML would happen automatically:


Levels of Certification

There are 3 levels of gbXML certification:

  1. Direct translation with no automation
  2. Basic automation where:
    • Surfaces are all defined and correctly converted
    • gbXML is valid XML
    • gbXML is legal gbXML as per the XSD
  3. Advanced automation where geometry from the authoring tool to a BEM-ready model with basic automation

Level 1 and Level 2 test cases are essentially the same. The only difference is whether the tool makes it easier, through automation, to identify surface types without the user having to do it manually.

Level 3 test cases are new industry reach goals. No tools on the market today can achieve all of the Level 3 Test Cases. These are advanced benchmarks.

The total number of test cases is in flux. We expect that our user community will send emails asking for more test cases when they find a flaw in vendor software.

All test cases must be passed to achieve a full “Level 1”, “Level 2”, etc. certification.

See the image below for more information on the levels of certification.


Example of Certification Process

Our first validation customer has been the National Renewable Energy Lab (NREL). We have been working with their OpenStudio software tool which works on top of EnergyPlus to calculate yearly building energy usage. OpenStudio has enountered some difficulty in passing all of the tests. The reasons for this are two-fold:

  1. The nature of some of the test cases are beyond OpenStudio’s intended scope
  2. The validator has also been found to be too stringent

Some of these stringency issues include:

  1. No allowance for metric units, or mixed metric and I-P units
  2. Ambiguous acceptance of interior ceilings or floors
  3. Does the azimuth and lower left hand coordinate truly have meaning for horizontal surfaces?
  4. Handling geometry from egg-shell tools (e.g. – SketchUp, FormIt
  5. Handling geometry from tools with Interior Surface enumeration (Bentley)
  6. Better abstraction of wall polygons

Handling Different Types of Geometry

Handling Geometry From Egg-Shell Modelers (SketchUp, FormIt):
If all surfaces and zones are drawn on the centerline:

  • The surface vertices will be correct (because surface vertices are defined at the centerline)
  • But the area and volume calculations will be incorrect (when compared to a thick wall representation). Areas and volumes, by definition, must take into account wall thicknesses.

Solution: Tweak the validation process.
We will make special considerations for the
area and volume calculation if the vendor is
submitting for a geometry modeler like this.


Handling Geometry From Interior Surface Modelers (Bentley):
If all surfaces and zones are represented as interior:

  • The surface vertices will be incorrect (because surface vertices are normally defined at the centerline)
  • But the area and volume calculations will be correct (when compared to a thick wall representation). Areas and volumes, by definition, must take into account wall thicknesses.

Solution: Tweak the validation process.
We will make special considerations for the
area and volume calculation if the vendor is
submitting for a geometry modeler like this.


OpenStudio Validation Findings:
OpenStudio has encountered difficulty passing all the tests.


  • The nature of some of the test cases are beyond OpenStudio’s intended scope
  • The validator has also been found to be too stringent


  • The current validation documentation could be improved, with more clarity
  • Validator interface could be improved to clarify why the test is passing or failing

gbXML is Proposing Changes to Simplify and Clarify Compliance:
OpenStudio has encountered difficulty passing all the tests.


  • The nature of certain test cases is beyond OpenStudio’s intended scope
  • The validator is too stringent
  • Documentation needs to clarify what is being tested
  • Validator interface could improve to clarify why a test passed or failed

gbXML’s forward-looking position:

  • The number of test cases required to pass needs to decrease
  • The validator requirements will relax
  • Documentation is to be improved, and put online
  • Validator interface is also going to be improved to be more clear

ASHRAE 90.1 Web Software

ASHRAE 90.1 Web Software

For years, we have worked with ASHRAE to develop mobile applications related to a number of their standards and Handbook of Fundamentals chapters including ASHRAE 62.1 Standard, a duct fitting database app (which is quite popular, surprisingly), and an interactive psychrometric chart app. These apps have all helped bolster ASHRAE’s entry into the mobile age. Below are descriptions and screenshots of the various apps we have developed for ASHRAE:

Duct Fitting Database
The HVAC ASHRAE Duct Fitting Database (DFDB) app for the iPhone and iPad allows users to perform pressure loss calculations for all 243 ASHRAE fittings listed in the ASHRAE Handbook of Fundamentals.




This app is based upon the popular ASHRAE Duct Fitting Database desktop application, and you can do pretty much everything in this app that you can do in the desktop program that is offered by ASHRAE. The advantage of this mobile app is that you can easily use it out in the field to perform quick duct pressure loss calculations. The following is a list of features of this app:

  • You can create individual projects, each with unique input values and results.
  • Each fitting has its own custom set of input parameters and results
  • It includes a useful search feature that allows you to type in a partial or full fitting code name to quickly retrieve it.
  • It allows you to display and email two types of reports. These are similar to the reports available in the desktop version of the DFDB software. The app reports also include a spreadsheet attachment that you can open on your desktop computer to do further analysis.
  • All fittings include pictures that you can view within the app.
  • The app displays inputs and results in both english and metric units.

ASHRAE 62.1 App
The HVAC ASHRAE 62.1-2013 app for the iPhone allows you to perform comprehensive minimum ventilation calculations for a wide variety of commercial buildings based upon Standards 62.1-2007 and 2010/2013 (which are essentially the same). This app is based upon the “62MZCalc.xls” Excel spreadsheet that accompanies each copy of the ASHRAE 62.1 User’s Manual. You can do pretty much everything in this app that you can do in the Excel spreadsheet, in addition to creating multi-system projects and emailing results so you can perform further analysis.




ASHRAE Psychrometric Chart
The HVAC Psychrometric Chart (HVAC Psych Chart) app is the first truly interactive graphical psychrometric chart for the iPad, and it includes both IP and SI units. Using your finger, you can easily plot HVAC and other psychrometric processes on the iPad screen while out in the field, save the graphs, and then email the graph and results to clients.

It includes a number of features that allow the user to:

  • Customize the graph in many different ways including specifying the psychrometric chart line colors, chart background color, hide/display status of chart lines, point colors, process line colors, units of graph values, and the min/max limits of the chart
  • Create non-standard charts with high maximum dry-bulb temperatures or ones for high altitudes and low barometric pressures
  • Using a finger, plot as many points as wanted on the screen. As the user moves their finger around the graph, the psychrometric properties at the top of the screen dynamically update. In addition, users can double-tap a point to display the point properties and then edit them




ASHRAE Standard 90.1
ASHRAE 90.1 (Energy Standard for Buildings Except Low-Rise Residential Buildings) is a United States standard that provides minimum requirements for energy efficient designs for buildings except for low-rise residential buildings. Percent improvement over ASHRAE 90.1 is the basis for awarding energy points within the LEED rating system. In addition, many states apply ASHRAE 90.1 to buildings being constructed or under renovation.

There are 2 methods of complying with ASHRAE 90.1: the prescriptive and performance paths. The prescriptive path requires that all components of the building meet the minimum standards specified by ASHRAE 90.1. The performance path involves modeling the proposed building design and demonstrating (through building energy simulation) that it uses less energy than a baseline building built to ASHRAE 90.1 specifications. In the performance path approach, a baseline Energy Cost Budget (ECB) is established, based on the building size and program.

Section 11 of Standard 90.1 describes the ECB Method, an alternative approach to demonstrating compliance of a building design with Standard 90.1. Compliance with Section 11 is described in detail in Section 11.1.4 of the standard. With the ECB Method, a computer program is used to calculate the design energy cost for the proposed building design and to calculate the energy cost budget for a budget building design. In the budget building design, which is a variant of the proposed building design, all mandatory and prescriptive requirements of the Standard are applied. In other words, the energy cost budget represents the building as if it complied with the Standard. The design energy cost for the proposed design cannot exceed the energy cost budget.

This standard has always confounded us in terms of determining the best type of app or software tool to develop for it, and that’s ASHRAE Standard 90.1. ASHRAE 90.1 is such a comprehensive and wide ranging standard for building energy efficiency that is hard to develop just one software tool that will “automate” everything needed by stakeholders. We’ve talked with ASHRAE Publications for years and even created a joint SurveyMonkey to gauge interest in the type of software tool that would best serve the 90.1 community. Here are a couple of screenshots of the questions and responses from the SurveyMonkey:



Based upon the responses from the survey above and talking with members of the ASHRAE 90.1 standards committee, we decided to develop a software tool to aid in filling out the 90.1 Energy Cost Budget method (ECB) compliance form located on page 395 of the ASHRAE 90.1-2010 User’s Manual. At first, we were contemplating developing a mobile app for iOS, but then received feedback that most users would not use it in the field. Therefore, we decided to develop a web app that would work on any device (laptop, iOS, or Android) as long as it was connected to the Internet. This would allow users to easily use it in the office and in the field.

The web app that we developed is based upon a variation of the ECB forms that start on page 395 of the User’s Manual. The altered forms were developed into the form of an Excel spreadsheet by Greg McCall of Vancouver, Canada. The variations in the spreadsheet have helped better tailor the forms toward building code officials. For example, it breaks down the energy end use and fuel type sections into building, parkade, and site/other sections that allow for more intelligible categorization by space type within the building. In addition, the spreadsheet includes a number of statistical values that help code officials visualize the relationships between the different values.

The following two images are the ECB forms from the User’s Manual:



The 90.1 ECB website allows users to export all of the information and calculated results to an Excel spreadsheet in the exact same format as Greg McCall’s original spreadsheet. From this exported spreadsheet, you can alter values, export reports to PDF, and print reports. Below is a sample of the statistics page in the web app:


While not everyone is utilizing the standard by implementing the ECB method, this web application is a good start to digitizing the ASHRAE 90.1 standard. The link to the ASHRAE 90.1 website is here:

Any feedback is much appreciated:

Equipment Selection Software

Equipment Selection Software

We have developed a number of equipment selection software tools over the years. While this type of software is not the sexiest type of software out there and its user-base is quite small compared to games or word processors, we feel that this type of software is quite interesting to develop. I’d like to share a bit about our experiences with developing 2 different types of equipment software selection tools for several large HVAC manufacturing companies.

What is equipment selection software exactly? It is a computerized or digital tool that allows users to properly choose the correct HVAC manufacturer’s model equipment based upon a wide variety of input and/or output parameters. Depending upon the type of equipment, the parameters can vary greatly. For example, HVAC humidification equipment requires input parameters such as outdoor weather conditions, elevation, indoor air temperature and humidity, and required outlet air conditions.

Users of this type of software include HVAC engineers, manufacturers representatives, and manufacturer salespeople. These tools can be web, tablet, or desktop based software applications.

Mitsubishi Electric
We were hired by Mitsubishi Electric (ME) of America to develop an equipment selection desktop software tool for their line of VRF (variable refrigerant flow) HVAC equipment. They insisted that the tool have a graphically intensive user interface with lots of drag-and-drop functionality. The software tool would allow users to lay out a schematic of the VRF system including the outdoor unit, indoor units, connectors, pipes, and other components. The tool would be strictly rule-based so it would inform the user as to whether a certain length of pipe was allowed or if a certain model outdoor unit could be paired with a specific indoor unit. The types of outputs were numerous including PDF reports, AutoCAD schematics, spreadsheet outputs, XML, and even proprietary file format output to a Mitsubishi controller.




Other functionality included the ability to dynamically update and add new equipment model information, localization include language and regional models for different areas of the world, and ability to layout controls wiring.

This projected took about 3 years to fully develop and finally deploy to end users including Mitsubishi engineers, resellers, and salespeople.

Some takeaways from this project:


1. It took much longer to develop than originally planned (no surprise, here). Between changing requirements and long approval waiting periods, the timeline almost tripled.

2. Localizing software tools is a very complex endeavor. It not only involves translation files for one or more languages, but it also involves filtering equipment selections depending upon the region of the world.  Also, numerical values must be displayed in English or Metric units depending upon the region.

3. Integrating with popular third-party software tools such as AutoCAD is a never ending process since there are so many versions of AutoCAD that it is impossible to universally integrate with all of the versions. Therefore, a number of users who have incompatible versions of the tool are not able to utilize the functionality.

Advantix Systems
Advantix Systems is an HVAC manufacturer of dehumidification equipment. They have a patented, liquid desiccant technology that both cools and dehumidifies simultaneously, eliminating the need to overcool the air to control humidity. It’s actually quite ingenious, and the image below shows how this works:

This image courtesy of Advantix Systems:
As you can see from the psychrometric chart, dehumidification occurs without having to ride the saturation curve (green versus purple). This is an amazing engineering accomplishment, since now there is no need to waste energy on reheating the temperature from the saturation curve to the required dehumidification point.

Advantix Systems hired Carmel Software to develop a web-based equipment selection software tool that would allow reps and engineers to quickly select and price equipment based upon required conditions. Features included:

  1. Creating a quick rating of a product (or set of products) given inlet conditions (airflow, temperature, humidity) and an Advantix model number. It would display product performances (decrease in temperature and moisture removal, outlet conditions, energy removed (total and latent).
  2. Creating a quick selection of equipment under specific conditions (temperature, humidity, airflow, desired outlet temperature and humidity or desired temperature decrease and moisture removal) and allow the user to select from 1 or more models that satisfy the required outlet conditions
  3. Creating guided selections that ask the user a number of leading questions that tell the software which models are most appropriate
  4. Providing relevant PDF submittal documentation for selected equipment
  5. Ability to manage equipment performance, documentation and options by either editing or adding new equipment.

Key Takeaways

This was an extremely complicated project due to a number of factors including:

  1. It was extremely calculation intensive. Not only were there complex psychrometric calculations, but complicated logic to select the most optimal equipment either by efficiency or cost standards. In other words, we weren’t done after the basic psych calcs. There was a lot more to do after calculating the outlet conditions including develop complex logic to iterate through 100s of scenarios to determine the optimal equipment configuration.
  2. There were lots of reporting requirements requested by the client. Not only were we dynamically generating PDF submittals, but also drawing elevation-specific psychrometric charts with all process points and lines.
  3. As is a common theme here and with almost all specialty software development companies, this project took far longer than originally planned by either parties. This was mainly due to changing requirements and complex logic that far exceeded our expectations.

Here are some screenshots of the web-based selection software: