An important aspect of good design is simplicity. HVAC can be complicated enough, given the need to maintain various spaces at set temperatures, [...]]]> Simple is as simple does. It works. Its easier to understand. Easier to fix. The real world does not reward complexity.

An important aspect of good design is simplicity. HVAC can be complicated enough, given the need to maintain various spaces at set temperatures, relative humidity and cleanliness. HVAC systems are also expected to maintain certain pressurization and [code required] outside air exchange. All while keeping to the highest possible energy efficiency. We also need and expect them to respond precisely and correctly to changing variables.

Simplicity in controls are also key to this. The simplest controls are on-off. Simplicity is not obvious everywhere. But in reality, as software development theory teaches, you can find the simple by decomposing the complicated.

Consider these concepts before the initial Basis of Design is established. Decompose the various functions needed and decide how the system will be controlled. Many designers have their personal preferences and presumptions, but these must be put aside in favor of open-mindedness in the beginning of the decision making process. Yes, energy and size calculations may be useful, but not as important as what and how to control the various environmental parameters.

Diagrams of the systems,

Mass-flows, temperatures, and pressures. For lighting, its watts and lumens per square foot. And using natural ambient light wherever available.

Get these right the first time, and you will save all kinds of hassle. During design, keep the diagrams as a guide and reference. It will keep also you focused and directed.

Next subject: Dedicated outside air systems (DOAS) These kinds of systems separate the ventilation "function" from the building internal HVAC. Tens of millions of buildings have no way to split this from the basic heating and cooling. Which makes the controls complicated. DOAS is especially good for high occupancy rooms and in situations where air change requirements are more exacting. Its an economic question and we have to decide how and whether this is worth the trouble. Most significant in schools, assembly rooms, theaters, health care,

In many existing buildings, DOAS, which require separate main ducts, may be impossible to retrofit due to space limitations and structural issues. But DOAS divides the work that HVAC systems do, they can be used to recover energy that is lost by exhaust systems. Furthermore, because DOAS central units can be physically remote, so they do not contribute noise to the occupied space and finally, they incorporate the potential to increase net rentable space!

An alternative, if the above is not economically feasible, is to keep and/or update the existing systems, measure carbon dioxide levels (a proxy for stale air), and control the entering outside air according to that parameter. This is "Demand Controlled Ventilation" control, which I described in this previous post in November.

The Buildings Sector accounts for about 40% of U.S. Energy, 72% of Electricity, and 34% of Natural Gas use. Building energy costs totaled $390 billion in 2006. The Buildings Sector accounts for about 40% of U.S. Energy, 72% of Electricity, and 34% of Natural Gas [...]]]> The guys over at Autodesk made this cute animation to drive the point home

The Buildings Sector accounts for about 40% of U.S. Energy, 72% of Electricity, and 34% of Natural Gas use. Building energy costs totaled $390 billion in 2006.
The Buildings Sector accounts for about 40% of U.S. Energy, 72% of Electricity,
and 34% of Natural Gas use. Building energy costs totaled $390 billion in 2006.
Source: Buildings Energy Data Book, Sept. 2008

NAMING THINGS and SHARING (it’s a matter of INTEGRITY) Naming comes up again. “Inconsistent” is the keyword. I am glad that I am not the only one who struggles with it. Shakespeare wrote “What’s in a name? That which we call [...]]]> Delayed commentary on things learned and shared at a recent RevitDC meeting:

NAMING THINGS and SHARING (it’s a matter of INTEGRITY)
Naming comes up again. “Inconsistent” is the keyword. I am glad that I am not the only one who struggles with it. Shakespeare wrote “What’s in a name? That which we call a rose by any other name would smell as sweet…” ….NOT IN computing and a BIM (building information model) it WON’T!

Naming standards: a concept that could save billions of dollars!
More often than not, architects have provided drawings with non-standard names for the layers and “blocks” (which are nothing more than buckets). And these often contain attributes with yet more non-standard names. Trouble in data-city. [IMO, Autocad's over-reliance on the two “object-types” they call blocks and layers has created a stunting effect. Many former CAD users will need to unlearn them to use Revit.]

Make no mistake about it: CAD is a form of database, (albeit a limited dataset). But for a database to work decently, the rules must be created, followed, and applied consistently. (Ref: Database design manuals and texts) That said, think about the naming and organization that happens in the contract documents, never mind CAD. An article on BIM that I wrote for fellow engineers, but all stakeholders should read.

Should we require database design courses for BUILDING ARCHITECTS?
The building designers (architects) take notice: a change to a layer name can (and has) wreaked havoc on many things. All the way back to my spreadsheets! For example: countless times, even predating CAD, I have been surprised by changes made by an architect on the room names and numbers, and being forced to MANUALLY repair these on the mechanical, electrical and plumbing documents. Not to mention the many calculations that depend on these. Things like lighting and HVAC calculations. (This issue will hopefully die down in a few years, although I had expected this issue to be solved by now)

Blocks and layers are useful for rough collections of data, but they have always been “rough”. Even after 20 years of the technology. This is one reason why Autodesk bought out Revit. They knew that Autocad could not compare to Revit in the evolution of Building information Modeling.

Data organization apparently is not a favorite topic among architects and engineers. It is more interesting to IT pros and a few more forward-looking architects engineers like myself. But this is no less relevant to the building information model (design and contract documents).

So it happens that subject-matter experts and cross-trained folks, like myself, are breaking through the walls (pun intended) that separate the disciplines. Witness the XML schemas being developed by groups like ASHRAE (who are guiding gbXML) and the Associated General Contractors of America (directing agcXML). These standards will make the BIMs easier to use.

DISTRIBUTED DESIGN
Over the years, we have come to share our drawings by the use of the so-called “external reference”. Autocad called them “X-reference” plans; a way of sharing CAD ‘drawings’ between workstations. Many drawings may use or even “depend” on an X-referenced plan. The beauty of it: make a change in one place, and it will propagate to all the dependent views.

The increased popularity of BIM and BIM software demonstrates that a high priority is being given to real-time sharing. An understanding of the true benefit has FINALLY trickled up to many decision-making managers. No more silos of information! The lighting designer, HVAC designer and the architect can collaborate on the glass and shading all the time, not just at the weekly meeting!!! YAY!!! The cost consultants can do their cost analysis on an ongoing basis, not after the design is 80% complete and when the changes are most costly and disruptive.

What happens as the building design is developed – At RevitDC, I learned that Revit doesn’t implement automatic notification to other team members/users of changes. Someone said, “You don’t know what you don’t know”. YIKES! Something is not right about that.

Copy/monitor issues were mentioned. The use of the word “copy” is a confusing terminology that resembles the CAD problems of updating. Are we not talking about a central database?

I also heard about sluggishness. Why is bandwidth still being discussed ? Paying for a fast Internet connection is cheaper than the mistakes a slow connection can cause. At the Revit DC meeting they discuss only Autodesk Revit. So it appears that it has an ongoing problem with its communication architecture. Come on !!!

The distributed computing model came late to Revit, I think. Graphisoft’s Archicad and Bentley’s Building don’t seem to have this problem. Revit was not originally designed for distributed computing using large databases. It was intended for a smaller audience in the beginning. They had a communication issue at some point and it looks and feels like it has some sort of workaround ever since. Maybe Revit is showing signs of stress and strains and may be replaced?

Archicad seems to have the distributed data and updating part smoothed out. (Did they take a cue from Oracle?) I have heard that Archicad updates the distributed data almost seamlessly. Compare that to Revit, which seems to stop and start. Perhaps it goes back to the project data organization? Technical skill of the managers? Or is the Revit data scheme just plain bottlenecked?

CONNECTIONS
Kimon Onuma (of Onuma Software) mentioned the importance of “connections” at the RevitDC presentation. Connections are key indeed, and when I first heard this idea many years ago, I realized that good design creates good connections between objects, and having the objects themselves is only half the task. Learning this, like designing, is a practiced, intuitive, hands-on experience.

Connecting people and ideas is a cool thing.

To put some solid numbers on benefits of commissioning, Evan Mills, PhD, and colleagues at Lawrence Berkeley National Laboratory, Portland Energy Conservation, and Texas A&M University (Energy Systems Laboratory) reviewed published [...]]]> I would like to share this 2006 excerpt from the Building Design and Construction magazine white paper on the bottom line of building commissioning.

To put some solid numbers on benefits of commissioning, Evan Mills, PhD, and colleagues at Lawrence Berkeley National Laboratory, Portland Energy Conservation, and Texas A&M University (Energy Systems Laboratory) reviewed published and unpublished data on 224 buildings in 21 states, representing 30.4 million sf of commissioned space—73% in existing buildings, 27% in new ones. Total commissioning costs for these buildings were $17 million (2003 dollars), an average $0.55/sf.

Among their findings:
■ An average 11 deficiencies were found in existing buildings, 28 in new buildings. HVAC systems represented the bulk of the problems.
■ For existing buildings, median commissioning costs were $0.27/sf; energy savings came to a median 15% (18% average); payback times were less than nine months (0.7 years).
■ For new buildings, commissioning costs were $1.00/sf (0.6% of total construction costs), yielding a median payback of 4.8 years.
■ Reduced change orders and other non-energy benefits accounted for $0.18/sf savings in existing buildings and $1.24/sf for new construction— “comparable to the entire cost of commissioning,” the researchers note.

The authors conclude that “commissioning is one of the most cost-effective means of improving energy efficiency in commercial buildings.” While not a panacea, they admit, it is “one of the most cost-effective and far-reaching means of improving the energy efficiency of buildings.”

Post-occupancy evaluations can help property owners, developers, and AEC firms determine how buildings are functioning for tenants or occupants.

What can I add to this? Implementation and testing YOUR PROJECT. CALL ME TODAY for a no-cost evaluation

A better [...]]]> What if? Energy independence, green jobs, deal with peak oil , have healthier children, cleaner air and water, save the rainforests….

A better world hoax

LEED certified office buildings excel

Additional editorial on LEED and Energy [...]]]> This doesn’t need any explanation.

LEED certified office buildings excel

Additional editorial on LEED and Energy Star marketability

For generations, we engineers depended on drawings. The desktop PC, and software, such as Autocad, changed our dependence into a 2-d CAD.

Stephen Roth wrote in the recent issue of Consulting Specifying Engineers magazine.

HVAC cooling [...]]]> Change is in the wind. Software and information technology forces a break with the past.

For generations, we engineers depended on drawings. The desktop PC, and software, such as Autocad, changed our dependence into a 2-d CAD.

Stephen Roth wrote in the recent issue of Consulting Specifying Engineers magazine.

HVAC cooling and heating load analysis for buildings currently is performed by using widely available software tools. For the past 25 years, this method has become the status quo for HVAC design engineers, and it has proven to be an effective way to accurately calculate building cooling and heating losses….

His point is that the status quo is entrenched.

The energy crisis in the 1970s was a wake-up call for HVAC engineers to more accurately calculate the cooling and heating loads for a building. The 1980s saw the advent of software that could be used by both small and large engineering firms to accurately calculate the building cooling and heating loads. This was a big change in the way HVAC engineers performed their building analysis, and it provided more accurate results than previous methods.

I came into this business as this software came onto the scene. And I have been doing energy modeling with spreadsheets ever since they became available in 1981 or so.

HVAC analysis software is quite complex, and its use often requires a solid engineering background and extensive training. This leaves architects at the mercy of HVAC engineers when doing this type of analysis at early stages of design

I feel I should apologize to all those architects who I have intimidated over the years.

Later in the article Roth says:

There are some disadvantages to using 3-D BIM versus tabular input methods for load calculation purposes including:

Learning to use 3-D modeling tools requires in-depth training and a new way of thinking about mechanical design. Many engineers simply may be too entrenched in their ways to accept such a shift in thinking. In addition, the cost of the software licenses and training may be prohibitive for many engineering firms. Complex 3-D modeling software often requires at least a week of formalized training and many months of on-the-job learning…

read the entire article here

I agree completely.