Noel's Green (make that SUSTAINABLE) Blog » HVAC

Dependence on oil has a BIG cost

noel — Mon, 03 May 2010 22:28:06 +0000

the common Oil slick

The massive oil spill in the Gulf of Mexico is too big price to pay for our dependency on oil. Now we have to re-evaluate our energy plans. FINALLY. The sustainable approach is to stop drilling and spend more money on energy conserving measures and renewables.
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In this months supplement to Engineered Systems magazine, there was an interesting editorial
The Way I See It: Saving Billions — One Customer At A Time by Randy Rawson, the President of the American Boiler Manufacturers Association. He said:

“The great unfathomable mystery of why commercial, institutional, and industrial upper management remains so averse to saving money and, where appropriate, increasing shareholder value through greater attention to their energy use continues to dog this industry, despite all our efforts to the contrary.

So why is industry dogged by an aversion to saving money? I am sure it is lack of proper education and understanding. Science and math have been battered and beaten down in the US. So many good brains have ended up playing on Wall Street. This is a case of lots of money and potential income streams “hiding in plain sight” due to lack of recognition by those in charge.

Imagine a mile long parade of armored cars, all filled to bursting with 100 dollar bills, passing by a board room during a meeting. The parade stops for a moment, and then returns to the bank. When the executives ask why the money was not delivered, the engineers tell them, “Sorry, you have to TAKE ACTION FIRST (replace the boilers), then you get the money, you monkeys!”

Better HVAC can save $48 billion/year in the USA

noel — Fri, 05 Feb 2010 21:16:55 +0000

The latest numbers are that US buildings consume $320 billion/year in energy. 2/5 of all the energy used in the US. And about 40% of the energy (costing $120 billion/year) is used in buildings for HVAC.

Some of the 2009 stats HVAC designs that I have incorporated recently into my office building projects are expected to use 30% less than the levels allowed by the local and state building codes. (ASHRAE Energy code 90.1-2004).

Consider that more than 70 percent of existing commercial buildings in the country were constructed prior to 1980 (according to floor area, see this 2001 study) . It is very likely that most of these older buildings consume well over the present building code allowable.

There are no laws requiring them to retrofit. The financial incentive to retrofit is all that exists, and unfortunately, this is another example of out-of sight, out-of-mind ignorance. (and HVAC and building energy use in general getting no respect).

These buildings should be retrofitted to reduce energy use a minimum of 30% and more. Up to $48-60 billion per year is being simply wasted. Wow! That is $200 a year for every man woman and child in the US. Almost half as much as we throw away on the war in Iraq. ($130 billion in 2007)

Hey, what are you waiting for, lets find out where the energy is going!

Lighting… I did not mention lighting: higher efficiency lighting and optimal daylighting could save ANOTHER $20 billion /year easy.

If you still a skeptic, please read: “Working Toward the Very Low Energy Consumption Building of the Future”

THE LAST ENERGY CRISIS- 1970s and a B.S. Environmental Design

noel — Tue, 19 Jan 2010 18:10:53 +0000

I have a BS ED, which is a science that encompasses the junction between engineering and architecture. My expertise is in buildings and how they work. I focused all my career on design of the built environment and building systems. I was educated in energy conservation, neighborhood preservation, and solar energy in the 1970s. I was trained to create design solutions for all kinds of advanced issues like

active and passive solar heating,
air conditioning,
historic building preservation
human factors like indoor air quality

I first learned how to do an energy model with pencil and paper. It was very exciting to learn how to design and justify energy conservation measures. Then the Energy Crisis went away about 1982. The energy recovery methods that I thought were so cool were no longer needed or cost effective. But the career path open to me was still basically HVAC controls and design. So, this is what I did, and this is what I do.

To be sure, most, if not all, of my professional peers are schooled in mechanical engineering. ( and they possess a B.S. Mechanical Engineering). I do not have that specialization. However, I am uniquely qualified and experienced.

Like many professional engineers today, my desire is to serve the design and construction industry. Many people do not remember the 1970s. I prepared for an energy shortage then, and I remain ready to help attack the problems of this new energy crisis.

The bottom line! Building commissioning today

noel — Mon, 11 Jan 2010 01:13:04 +0000

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

Demand Controlled Ventilation (DCV)

noel — Mon, 30 Nov 2009 20:14:12 +0000

A recent article in ASHRAE Journal, “An Updated Look at DCV Approaches“, October 2009, page 82-84, covers an important component of building energy: HVAC ventilation control, also called “Demand Controlled Ventilation“. It is an overview of the reasons and logic behind one of the more cost-effective methods for controlling air quality while reducing energy usage.

Outside air – Opening a window
Comfortable and clean indoor breathing has always been associated with fresh air. You simply dilute inside air with conditioned outside air. Its the same as opening a window (albeit with more precision). Scientific observation reinforces the correlation between fresh air and a comfortable indoor breathing environment.

Formal design procedures and requirements for this have been part of the building codes for several generations. ASHRAE Standard 62, “Ventilation for Acceptable Indoor Air Quality (IAQ)”, is usually the basis for these. In summary, ASHRAE 62 describes uses several methods which to determine the required volume of outside air. One common method relies on a “prescribed“ outside air quantity (volume/time) as determined by the maximum anticipated number of occupants. Outside air volumes often have a considerable impact on the HVAC energy load, therefore close attention is paid the precise control.

Controls – What is DCV?
There are several common methods for controlling outside air. The most common is the so-called “Demand Controlled Ventilation” whereby the addition of fresh air is only necessary according to the “demand” caused by occupancy. Carbon dioxide (CO2) concentration is a reasonable proxy for overall air quality, and it has been shown that the concentration of CO2 correlates well to the quantity (concentration ) of people in the space.

The Brutal Reality

One point in the article that sticks out was:

…traditional DCV systems use carbon dioxide sensors to indicate per person outdoor airflow rates. To accurately correlate CO2 levels to per-person outdoor airflow rates, sensors need to be installed, calibrated, and maintained properly.
Recent studies indicate that one or more of these steps generally are not followed in buildings with DCV (Fisk) and (Shrestha and Maxwell). One study showed that 80% of CO2 sensors in buildings read high by an average of approximately 40%, resulting in higher-than-needed ventilation rates.
Anecdotal evidence also suggests that it is common for DCV systems to be disabled when not working properly or complaints are received about IAQ.

Statistics can often lie. We need to see details on these results. But if this fact is true, I can offer an observation. Building (HVAC et al) controls tend to be near the back cover of the contract specifications. Heck, out of 27 divisions of the specs, the CO2 sensors are in division 25. The toilet stall accessories come before them!

So for this reason, Division 25 subcontractors often are forced to make do with the absolute low bid. Too often, not enough commissioning and testing is budgeted to sure the controls are robust and reporting correctly. Calibration is always an issue. Hardware needs to be commissioned as well, specs need to be tighter. The new technology can be compromised by mass adoption/application. We professionals should avoid this trap by being careful what we accept.

Recommissioning easily finds Issues
If problems with the DCV are latent, or undetected, the issue should come up during an Energy Star Audit via the measured CO2 levels. The service contractor may discover that room CO2 levels reported by the building sensors are significantly different from his measurements.

Regular HVAC service personnel do not always deal with HVAC controls at this level, but perhaps they should. Management should hire service contractors who can check the controls at least twice a year. In any event, this points up a need for re-commissioning. Hiring a “commissioning” firm that regularly performs such work and can identify issues is a good start.

LEED-EB (Existing buildings) commissioning and Energy Star commissioning practices are becoming more common, and those provide a framework of expectations for the future. Commissioning is no longer a process confined to million square foot projects being done by the likes of AECOM and Turner.

Over-ventilating to be safe?
Over-ventilating wastes energy and costs the building owner money. This is the common result of the failures mentioned above.

Marketing
There is a large swathe of commercial real estate in this country which has not been partly or fully screened for energy conservation measures. Perhaps half of all commercial real estate is operated and maintained as it has for decades. Owners and tenants send a lot of money to the utility companies. I love utilities, I invest in them, but I don’t love them THAT much.

So I say to the owners and operators of these facilities:
“Let us engineers walkthrough your building and find you a way to save on your energy expenses”

If you would like to discuss what services I can provide you and your clients, please feel free to contact me at noel@noelsusskind.com

Corporate Geothermal is a Renewable Energy tax credit…

noel — Sun, 20 Sep 2009 02:16:28 +0000

Corporate geothermal or (ground-coupled or pond-coupled ) HVAC systems are eligible for tax credits under the same law as renewable energy measures tax credits. Renewable energies (wind and solar) and combined heat-power systems get a 30% tax credit. A new geothermal /geocoupled heat pump investment will garner a 10% tax refund, which improves an already excellent investment into a compelling investment.

Slinky piping loops are promoted for their advantage of requiring less trenching due to greater piping surface area and increased heat transfer capacity of the style.

Slinky ground source piping loop

The payback on the geothermal was very fast without the tax break. In this economic environment, paybacks are reportedly at 1-5 years. 16-100% return is hard to deny. I recommend doing it.

The federal Business Energy Tax incentive law grants businesses these tax credits: (database search form)

An additional tax credit is available for HVAC, lighting and hot water: if the building is designed and built to use 50% or less energy consumption than code allowable maximums (as benchmarked by ASHRAE Standard 90.1-2001) for each of these three categories. $0.60/square foot for each of the categories, up to a maximum tax credit of $1.80/square foot.

Calculating the tax benefits

noel — Thu, 17 Sep 2009 13:57:24 +0000

While I was thinking about how to calculate the tax benefits of upgrading and changing or upgrading HVAC systems, lighting and hot water heaters, I decided to see if anyone had made a calculator to analyze it already. Sure enough, General Electric had created this EPact calculator

I have not had the time to test and validate this yet, but I’d be happy to hear from anyone who has. Please feel free to contact me through this blog.

BIM forces a break with status quo

noel — Mon, 14 Sep 2009 20:16:40 +0000

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.

Building Air Leakage and Air

noel — Sat, 12 Sep 2009 14:20:19 +0000

I just love this subject. Do you know whether your building is sucking or blowing? Did you know that even a new building, built to the usual building methods, will leak air? In a new project, the key is to make allowance for that, and design, build and validate accordingly. On an existing building, it is important to determine how much and where your building blows or sucks, so you can take action, if need be. Windows, doors, and construction joints all have a normal tendency to leak air or allow infiltration. Varying pressures within the building and across each envelope, causes air to move through these openings.

blower door

“Blower door” tests are a key tool for determining how much leakage occurs and in which direction, in (negative pressure) or out (positive pressure).

The major issues surrounding air leakage are indoor air quality, compromised comfort due to drafts or uneven temperatures, and energy usage. A good HVAC designer will account for all of these, and assure that undesirable effects, such as sucking cold or hot-humid in through the building joints is prevented. Likewise, a good architect/builder will account for the behavior of the envelope assembly, air leakage being but one behavior, in his/her design. (You can’t have a 100% tight envelope in practice, it rather more expensive to achieve 0% infiltration, so we plan for it, and plan to blow rather than suck. This rule does NOT apply to “clean rooms”, of course, where 0% infiltration is mandated.)

Blower door testing is a key component of new building commissioning or re-commissioning an existing building. If you know where all the intakes, exhausts, and door openings are, and their size and type, and then the remainder (theoretically) is the “tightness of the building’s construction”.

So building HVAC systems are commonly designed to create a slight positive pressure (blowing) at all times, to CONTROL infiltration. Design should always include some common sense and experience. ANSI/ASHRAE 62-2004, Ventilation for Acceptable Indoor Air Quality (IAQ), is the most commonly adopted code the prescribes indoor air quality and ventilation rates. The input of the ventilation code rules, combined with a input of air leakage rates, will guide the decisions on course of action.

Common reasons for buildings that suck and are uncomfortable include

obsolete HVAC controls,
building usage changes over time,
Increasing complexity of tenant build-out without corresponding update to HVAC
Increasing demand and complexity of schedules not adaptable to existing building
Increasing technological demand ( ie growing data communication rooms) not well integrated with the buildings older existing controls.

Solutions to these problems include

Periodic recommissioning of the HVAC systems and controls
Upgrading the HVAC controls
Sometimes existing building systems are just waiting to be replaced with simpler systems.

Many of us experienced energy modelers have been reliant on spreadsheets and/or dedicated heating and cooling calculation programs from the beginnings of our careers. But these methods are labor intensive and lately, we look more and more to BIM to help accelerate its use, or sometimes we are being required.

TECHNICAL POINT: How to model the air leakage in a building information model has been problematic up until very recently , I think. The recent releases last spring of new Revit add-ons (see the BIMOLOGY link to the right to read about ECOTECT ) give us some hope. I think that they are finally getting the details into the model. I could be wrong. But ideally it would be nice to specify and analyze air leakage across geometric boundaries on the fly.

In the end, its better to have a building envelope that blows a little, than a building that sucks at all.

ASHRAE 62-2001 synopsis on Internet(out-of-date in the exact details, so be careful)

Energy Engineering for your world

noel — Sat, 12 Sep 2009 05:13:04 +0000

Noel Susskind, PE, LEED AP is an experienced mechanical engineer and building energy expert ready to
serve you. Commercial, government, educational and healthcare facilities are a focus.
He will:

Serve as a high level resource on the latest science and art of building, or introduce you to one. Knowledge includes minimizing building energy (carbon) footprint via energy recovery, advanced control approaches , daylighting design, indoor air quality, ventilation, cogeneration, photovoltaic systems, etc.
Recommend energy-efficient design solutions and technologies, including lighting, HVAC, building envelope measures and passive solar and ventilation measures.
Validate and summarize energy audits of existing facilities by third parties.
Identify various alternative energy conservation measures and predict energy usage based on energy modeling. Includes economic analysis and financial projections with payback.
Work with the design and construction teams, sharing and validating others energy models (compliant with DOE-2 and BIM GbXML) as third party reviewer.
Provide documents and regular verification required for obtaining LEED energy credits.
Work closely with you on alternative solutions for building and system energy usage.