Technology and innovation have brought us great advances in energy efficiency.  As examples, just look at the shift from incandescent lights to fluorescent lights and now to LEDs, or the move to variable air volume (VAV) air distribution systems from constant volume during the energy crisis of the 1970s.  Those two evolutions alone have probably saved yotawatt[1] hours of electricity since they were introduced.  The trend continues today with things like advanced building lighting controls and energy recovery air handlers.

Stepping Backward

In the last several years, we have seen an explosion in the number of mobile devices be they cellphones, smart phones or tablets.  According to the Pew Research Center, 90% of all American adults have at least one cell phone and 64% have a smart phone.  Many of us have more than one device…and they all need to be charged!

Enter the plug-in rectifier. That’s what our smartphone charger really is, a device that converts AC power to the 5V DC required by our devices.  If you own one of these (which you do if you own a mobile device), you know they tend to get warm, even when nothing is plugged in.  That’s energy loss.  Some call it “vampire” or “phantom” load.

Combined Impact of Your Personal Load

The charger is siphoning off a little bit of electricity all the time it’s plugged in whether or not you are charging your device.  Phantom loads tend to be relatively small on an individual device basis and for this discussion we’ll assume that’s about 0.10 watts (real numbers vary all over the map and are likely higher than 0.10 W but I wanted to use a very conservative estimate). The US Census Bureau says there are about 250 million adults in the US.  If 90% of them own a cell phone and they each have a charger plugged into the wall that draws 0.10 watts when nothing is attached, that amounts to 131 million kilowatt-hours a year[2] of wasted electricity, or the equivalent of over 15,000 average US households.  The solution is easy enough, though.  Unplug them when they’re not in use.  Most of us don’t do that, unfortunately, but it’s still within our power to do so.  We are in control of those phantom loads.

Commercial Energy Loss

What we will not be in control of is the most recent evolution in technology that is becoming more and more pervasive.  These:

Any new hotel will have at least two of these in every room.  Hospitals are putting them into new or renovated patient rooms as well as common areas like waiting rooms and cafeterias and they are commonplace on college campuses.

It is not easy to find manufacturer’s data that tells you exactly what the phantom load is for a receptacle with two USB ports (as in the picture).  However, they all have them.  One large manufacturer has a published phantom loss of 0.63W per dual receptacle.  For the sake of argument and ease of math, let’s assume they average 0.50W.

A moderately sized hotel might have 120 rooms.  With two in each room and given similar use as my example above, those receptacles in this one hotel add up to 700kWh per year.  That’s equivalent to leaving two, 40W incandescent light bulbs on all year long.  I don’t know about the folks reading this, but when I was a kid, if I walked out of a room and left a light on it took about 3 seconds before I heard “hey, whaddya think…I own stock in the electric company?” —  my dad’s way of saying turn off the light if you don’t need it!

The USB ports actually draw power even when nothing is plugged in, so even if you do unplug your charger when not in use, these ports are still drawing a small phantom load. And, currently we have no way of turning these receptacles off when not in use.  Pretty soon you’ll be seeing these in new home construction and, possibly, added to commercial office buildings.  I can’t predict what the actual market penetration of these will be, but I’m pretty sure it will be significant.

One thought is to return to the old design of switched receptacles.  Wherever one of these gets installed, install a switch right next to it.  Add a red LED to the receptacle and the switch that illuminates when there’s power flowing to the receptacle and you’ve got a simple feedback mechanism.  At least that will put the control back in the user’s hands.

[1] One yottawatt-hour is 10²¹ kilowatt-hours, or in layman’s terms a colossal boat load.  Maybe yotawatts is a bit of an overestimate, I don’t really know, but it’s a cool word anyway.

[2] I assumed everyone charges their device overnight for 8 hours per day, leaving 16 hours per day of phantom load.

The post More Tech, More Energy Loss – A Shift in the Wrong Direction appeared first on Building Energy Resilience.

It’s that time of year again – summer – season of vacations, sunscreen (for me at least), mowing the lawn and (queue ominous music) the dreaded “Battle of the Office Thermostat.”  We all know what this is.  You go to work in an office and, if you’re a woman, when the man sitting next to you is perfectly comfortable you are teeth-chattering freezing.  If you’re a man and the woman next to you is comfortable, you feel hot and stuffy.  Disclaimer – I am a man.  Second disclaimer – I don’t wear skirts and sandals to work, even if it’s 90 degrees outside.

Image courtesy Flickr user starmanseries

A colleague sent me this article from the NY Times recently about how women are typically too cold in an air conditioned office and an “office formula [that] was devised for men” is partially blamed as being the culprit.  The Times article also quotes one of the authors of a recent study on the phenomenon as saying “in a lot of buildings, you see energy consumption is a lot higher because the standard [the formula to which I previously referred] is calibrated for men’s body heat production.” And finally, the NYT article goes on to say, “the study says most building thermostats follow a ‘thermal comfort model that was developed in the 1960s,’ which considers factors like air temperature, air speed, vapor pressure and clothing insulation, using a version of Fanger’s thermal comfort equation.”  Wow.  How wrong can they be?

To be clear, Fanger’s equation is used as part of ASHRAE Standard 55 to describe the varying levels of comfort in a space.  It has nothing to do with how a space is controlled, nor is it responsible for anyone’s discomfort.

Let’s start with those thermostats that follow Fanger’s equation. Huh?  There might be a thermostat out there that does this but I have never seen one and, frankly, I doubt it exists.  Maybe they have them on this bad boy  but not in our century or on our planet.  Thermostats are nothing more than temperature sensitive switches.  They turn the heat or AC on or off.  That’s it.  They are not like a dimmer on your lights or the accelerator in your car and they don’t know how to calculate the PVM as the article would have you believe.  Thermostats are a switch. They don’t use fancy equations, or any equations for that matter[1].  Some human being sets it to, say, 73 (the setpoint), and at some temperature slightly above 73 the AC turns on, then at some temperature slightly below 73 the AC turns off.  That difference between on and off is known as the hysteresis and is often about 2 degrees.  See the diagram below.  AC is set to 73, it turns on at 74, cools to 72, turns off, then the cycle repeats.  Whether or not that equation from the 1960’s is male-biased is completely irrelevant to how comfortable your office is.

Hysteresis diagram

Buildings with a Building Automation System (BAS) use the same temperature switches as thermostats.  BAS systems, however, have the additional ability to look at things like how quickly a space temperature has changed over time to better match the AC output to the current demand, but Fanger is nowhere to be found in those algorithms.  BAS systems use simple PID (usually only PI) controls to match system output to demand.  The humans in the office (or the human building manager) determine to what temperature the building is controlled.

What about the argument that building energy use is higher because Fanger’s equation was calibrated for men?  This could not be further from reality.  The equation has nothing to do with building energy consumption because it is not used to control building HVAC systems.  Buildings use more energy than they should be because of less-than-optimized HVAC system selection, poorly applied HVAC control strategies, building envelopes that are built only to meet code[2], if they meet code at all, and improper or inadequate maintenance and operation.  The first three can be addressed before buildings are built.  The first two can be cost-effectively addressed after the building is built with retro-commissioning and smart retrofits.  And the last can typically be overcome with adequate training of the building operators.

Is the battle of the thermostat real?  Absolutely.  It has to do largely with the differing metabolic rates found in men and women and, in my opinion, to a large extent the differences in how men and women dress for work in the summertime.  As I said, I do not wear skirts and sandals to work, but my female colleagues do, and sleeveless blouses as well.  They are able to dress for the 85 to 90 degree weather and still look professionally acceptable. In most office environments, however, men can’t do that yet.  Does the battle of the thermostat have anything to do with an equation from the 1960’s?  Absolutely not.  Sorry NY Times, you missed the mark on this one.

[1] Some thermostats are available with built in PI algorithms for stand-alone use but those do little more than turn the switch into something more akin to an accelerator.

[2] Meeting code, in my opinion, is like getting a D.  You have done only what you need to do to pass.  It is nothing to be proud of.

The post Battle of the Office Thermostat – Fanger Who? appeared first on Building Energy Resilience.

Whether your project is new construction, a retrofit, a major renovation, or a focused building upgrade, my success as a commercial building commissioning provider relies heavily on the active participation of other team members. Despite having clear specifications, providing a thorough building commissioning plan, and explaining the process at a kickoff meeting with the owner and affected contractors, we often find that due to the complexity and fast pace of contemporary construction, team members are unclear as to their role in quality assurance and the commissioning process.

National Conference on Building Commissioning

On May 20, 2015 Rick Stehmeyer and I will be part of a panel discussion at this year’s National Conference on Building Commissioning (NCBC), hosted by the Building Commissioning Association (BCA), the title of which is “Whose Role is it Anyway?”  If you’ve ever seen the television program with a very similar name, the idea is similar. Toss out a topic and let the panelists riff on it from their own perspectives, presenting challenges, opportunities and offering experienced opinions on how to best integrate comprehensive building commissioning into multifaceted, time-constrained projects.  The full session description is here http://www.bcxa.org/training/ncbc-2015-attend/whose-role-is-it-anyway/

Interactive versus scripted

I’m looking forward to this session particularly because of the format. Generally when I’ve done presentations in the past, it’s been the traditional PowerPoint style format with a well prepared and well-rehearsed script. Don’t get me wrong, that works if you know your material, if you don’t put up slides packed with text, and if you have an engaging presentation style. The panel format at this year’s NCBC conference though, allows the panelists to speak freely, build on one another’s ideas as they come up and formulate thoughts and opinions that are informed by experience from three sides of the building commissioning process: commissioning provider, controls specialist, and general contractor.

An example, courtesy of the US military, of what NOT to do with PowerPoint

Building Commissioning: Whose Role is it Anyway?

If you have ever had experience with building commissioning, you may already know that the success of commissioning is very dependent on the ability of the commissioning agent to effectively communicate and to marshal the strengths and resources that other members of the team bring to the table. Without knowing from the start what those strengths and resources are though, a building commissioning provider is starting at a significant disadvantage. At the end of this year’s NCBC “Whose Role is it Anyway?” hour, I hope to have a more clearly defined picture of who could perform what role in a successful project — and how we as building commissioning providers can identify and leverage the unique assets that each team member brings to the table.

The post Building Commissioning: Whose Role is it Anyway? appeared first on Building Energy Resilience.

A good retrocommissioning (RCx) project will result in at least one of the following:

• Improved system performance in the form of more comfortable occupants
• Reduced energy use while still meeting the needs of the end users
• Simplified maintenance without compromise to performance or energy

A highly successful RCx project will be one that is well-defined and thorough and will result in all three.  Here’s how to make your next fan system RCx project highly successful.

Define Your Goals and Expectations

Define your goals. Photo by Flickr user Katie Dalton.

The foundation of any commissioning project is an Owner’s Project Requirements (OPR) document or its RCx analog, the Current Facilities Requirements (CFR).  Ben’s blog post discusses these in more detail.    It’s often the case that different players have different or even competing goals for a retro-commissioning project.  Taking the time to collaboratively establish the goals and priorities will guide the RCx process to a successful outcome.

Some Fan Basics

Fan systems have one purpose – to move air.  They are designed to move a certain quantity of air (typically measured in cubic feet per minute or CFM) against a certain resistance (typically called static pressure or SP and measured in inches of water column).  The product of those two values[1] determines how much energy will be used.  It stands to reason, then, that if you can reduce the CFM or the SP or both, your energy use will go down.  One other component to consider is how the fan is driven.  If it is driven with a belt, there will be losses associated with belt slippage that can amount to real dollars in lost energy.  See my prior post for more about belts.

Fans. Photo by Flickr user MIKI Yoshihito.

Reduce Air Flow

Looking for opportunities to reduce airflows should be high on your list of tasks.  A 10% reduction in airflow is equivalent to a 27% reduction in power.  That’s math that I love having on my side!  Opportunities to reduce airflow can be identified fairly easily.

As an example, in a constant volume air handling system, there will be reheat coils for each zone on the system.  If a particular zone coil is always providing some reheat, there is an opportunity to reduce airflow to that zone.  You can verify the coil’s operation using BMS trending or by using simple data loggers to log the supply air temperature from the AHU and after the reheat coil.

In variable volume systems, you will want to review the programmed minimum and maximum airflow values of your VAV boxes and identify opportunities to scale back based on changed space use or other factors.  You should also be looking to identify reheat coils that never stop heating as noted above.

In all cases, a reduction in airflow must be accompanied by appropriate analysis to ensure proper outside air ventilation and to maintain any needs for space dehumidification such as in an auditorium or a natatorium.

Reduce System Pressure

Reducing system pressure also reduces operating horsepower although not as dramatically as reducing airflow.  A 10% reduction in system pressure loss results in a 19% reduction in power, still pretty good bang for your buck.  For any fan system, the ductwork and air outlets / inlets should be reviewed for high pressure drop fittings and transitions.  In larger systems, replacing one or two nasty fittings can be quite cost effective.

Review components of your air handler to identify opportunities to reduce redundancy or replace one component with a similar one having a lower pressure drop.  For example, we have encountered numerous air handling systems with unnecessary, redundant filters in series or three sets of filters in series where two will certainly suffice.  Avoiding elbows too close to the fan outlet is important as well to ensure flow is fully developed in the duct before it is diverted.

Photo by Flickr user Pulpolux

In constant volume air handling systems, check your balancing dampers and ensure at least one of them is fully open.  If they are all throttled back, the fan is operating against an artificially applied restriction to meet its design CFM.  It would be fairly easy to re-sheave the fan / motor to slow it down to allow for at least one damper to be fully opened.  Also, take a look at any flexible ductwork to ensure it is properly supported and it transitions smoothly.  Flexible ductwork can impose a significant pressure drop if it gets kinked.

In variable volume systems, ensure the static pressure sensor that controls the fan speed is remote from the fan.  The old rule of thumb is 2/3 of the distance away from the fan down the index run of ductwork[2].  This ensures that the fan is allowed to modulate down with reduced loads.  When static pressure sensors are in the air handler or immediately after in the ductwork, the fan speed will not modulate appreciably.

In variable volume systems serving BMS controlled VAV boxes, static pressure reset is not only easy to implement and will save further energy but it is required by ASHRAE 90.1.

Correct Drive Losses

I mentioned belts above.  If you cannot replace the belt drive mechanism with a direct drive, consider “cog belts” as a replacement.  While traditional V-belts rely on friction between the belt and pulley, cog belts work more like a bicycle chain, engaging directly with teeth on the pulleys to eliminate slippage.

Photo by Flickr user shehan peruma

Consider Replacement Options

As a fan system approaches the end of its useful life, a facility should prepare for its replacement.  This becomes an opportunity to revisit the fans themselves.  A replace-in-kind strategy is certainly the easiest and may be the most effective and efficient solution.  However, taking a step back and reassessing the options is always good practice.  In a system of roughly 20,000 CFM capacity or more, consider a fan array in lieu of a direct replacement.  A fan array utilizes multiple, direct drive fans in parallel in lieu of one large fan.  This approach builds in redundancy, creates a much more uniform airflow profile across an air handler, and can take up significantly less length.  Added redundancy and efficiency gains are always a good bet.

How to Retrocommission Fan Systems for Sweet ROI

Embarking on the RCx of any fan system requires defining the criteria for success, prudent planning, and keeping an eye on how to most effectively achieve the project goals.  Very often, occupant comfort issues and excessive maintenance are a result of improper airflow control or misapplied systems.  Properly retro-commissioning your fan system will very often lead to reduced time babysitting finicky equipment, more comfortable building occupants, increased reliability and lower energy costs. All in all, a sweet ROI.

[1] Naturally, it’s not quite that simple.  The equation for fan operating power or brake horsepower can be found here and in many other commonly available resources but the volume and resistance are the driving factors.

[2] ASHRAE 90.1 requires it be positioned so the controlling setpoint is no more than 1/3 of the total fan static pressure.

The post How to Retrocommission Fan Systems for Sweet ROI appeared first on Building Energy Resilience.

Introduction

End users of a building want to inhabit a space that provides, among other things, a comfortable environment with respect to ventilation and thermal comfort.  Thermal comfort is typically comprised of two things: temperature and moisture content (aka relative humidity).  Ventilation comfort is derived from providing enough outdoor air to a space to satisfy peoples’ need for oxygen, and mitigate buildup of odors as well as other air borne irritants and contaminants.  HVAC systems can easily achieve these goals while simultaneously being energy hogs and maintenance nightmares.

“The devil is in the details” is a phase we’re all familiar with.  Here, it pertains to the difference between what I call “drive by commissioning,” and detailed, specific functional performance testing (FPT) of HVAC systems and equipment which is necessary to identify incomplete or incorrect programming that will affect long term energy consumption.

How it Should Be Done

For the sake of this discussion I am focusing on HVAC testing but this can be applied to any building system.  Functional Performance Testing is commissioning parlance for verifying that systems are set up to operate correctly.  We work with a number of different contractors and have heard more than once (fortunately in a joking manner), “Ugh … you guys … I was hoping it was going to be so-and-so because he only shows up at the end and looks at the graphics.”

Cx Associates’ engineers really get into their work!

HVAC FPT is a vetting of the controls system.  As such, there are two important underlying questions to which we have to have correct answers in order to say the system works as intended.  The first question is, “what is this system supposed to do?” and the second is “how is it supposed to do it?”

Three Examples

To understand the importance of adequately answering both questions let’s consider the following three scenarios, all of which I have encountered first hand:

1. Four-pipe fan coils typically have a heating and a cooling coil with separately controlled valves.  In answer to the first question, this system is supposed to heat or cool the space it serves.  The right answer to the second question is that is should do this without both heating and cooling simultaneously.  Let’s assume the fan coil is arranged with the heating coil downstream of the cooling coil.  If the cooling coil is partially open (or even, maybe, fully open) and the space is too cool, the heating coil can usually overcome that to warm the space.  Space temperature remains satisfied, occupants don’t complain, but the fan coil uses a significantly higher amount of heating and cooling energy than required.  Unless this unit is tested in detail, step by step, this may never be noticed and the system would waste energy for years.
2. A more specific example involving a particular fan coil involves outdoor air not being delivered to the space.  The same fan coil noted above, is now serving a kitchenette.  The original design called for a range hood that was exhausted to the outdoors by a dedicated fan.  This was changed at an early stage of construction to be a simple, residential-style, recirculation hood with no need for an exhaust fan.  The outdoor air damper serving that fan coil was programmed to open when the (non-existent) exhaust fan status was proven on.  Well…without a fan, you’ll never get positive fan status (hopefully) and so the space would never get any ventilation air.  The unit maintains space temperature, so no one complains, but had this not been tested thoroughly, this space would not have been adequately ventilated.
3. We recently commissioned a project pursuing a LEED certification, and the team decided to attempt the IAQ credit requiring a flush out of the space with a certain amount of outdoor air before occupancy.  In order to ensure the air handling unit provided the right amount of air in the right amount of time, the controls contractor overrode the fan to be on in all conditions.  We ran through a number of operational tests on this unit and then performed an unoccupied mode shutdown test.  The unit shut down, but would not restart.  After poking through the programming logic we discovered that the fan would not start unless the outdoor air damper was proven open by an end switch, but the outdoor air damper was programmed not to open unless the fan status was proven on.  This was circular logic that would never have allowed the unit to start.  The occupancy schedule for this unit is occupied Monday – Friday, 24 hours, and unoccupied Saturdays and Sundays.  I suspect that once the flush out was over, the contractor, working Monday – Friday, would have put the unit in fully automatic mode during the week and it would have remained running.  It wouldn’t have been until the following Monday, when the unit didn’t start, that anyone would have realized there was an issue.

The above are just three examples of how methodical functional testing can uncover underlying operational issues that may otherwise go unnoticed.

The devil is in the details.

The post Functional Performance Testing Done Right: Details Matter appeared first on Building Energy Resilience.

We live and work in an age where communication can happen in an instant.  Emails circumnavigate the globe in a couple of seconds, text messages ding on our phones as soon as they’re sent and usually expect an immediate response, and our cell phones can be called no matter where we are or what time of day it is.  While this hyper connectivity does have the potential to streamline how we interact and do business and make our lives easier, I am finding effective communication to be more and more difficult. From what I’ve observed, people are simply overwhelmed by the volume of input they are receiving.  This results in their inability to respond to requests in a timely fashion or, if they do respond, it is often incomplete, misses the point, or is unclear because of a misunderstanding of the original request (likely due to the fact that they didn’t think they had the time to listen to the entire voicemail or read the whole email).

email (Photo credit: Sean MacEntee)

The Email Charter

I got an email this morning from a colleague with this link www.emailcharter.org that I found quite pertinent to this post.  I encourage you go to that site to learn about its origins and its backgrounds.  You can find the Email Charter at the end of this post.

These folks have put together “10 Rules to Reverse the Email Spiral”(the spiral being how much of our work lives are consumed by email).  The only one I take partial exception to is #2 which states:

Short or Slow is not Rude
Let’s mutually agree to cut each other some slack. Given the email load we’re all facing, it’s OK if replies take a while coming and if they don’t give detailed responses to all your questions. No one wants to come over as brusque, so please don’t take it personally. We just want our lives back!

The partial exception I take is to the detailed response part.  I, personally, try not to ask questions to which I don’t want answers.  If I ask it, please answer it.  If my question was poorly formed, I apologize for being imperfect but rather than ignore it, give me a call and we’ll sort it out.  Otherwise, I will be trying to follow the Charter and I hope you do too!

Email email email (Photo credit: RambergMediaImages)

One quick note on text messages…

I use them, my colleagues use them and my clients use them.  I think they offer a good tool to convey a quick thought or ask a quick question and they are certainly less intrusive than a phone call can be.  Text messages, are, however, NOT meant to be emails.  If you have a question or a comment that is longer than, say, 7 words and you need an answer fairly quickly, call me.  Remember that text messages offer even less context and less of an opportunity to express the correct tone than email. So, save text messages for very short questions that require very short answers. And, since many of us use our personal cell phones for work, send text messages only during normal work hours. Finally, check out Lifehacker’s tips for taming the email flow, and getting to “inbox zero.”

The Email Charter: http://www.emailcharter.org/

The post Communication Frustration appeared first on Building Energy Resilience.

Energy savings opportunities can be difficult to implement at times because of the perceived financial impacts they may have on a project.  All too often a short-sighted view is taken with regard to a marginal increase in project cost vs. the long term cost reduction impacts that marginal cost will achieve.

In Brent Weigel’s recent blog post, “Life Cycle Costing for Building Investments,” he describes the merits of Life Cycle Cost analyses rather than the limiting “Simple Payback” analysis approach.  I would like to propose to owners, construction managers and engineers a simple, yet often overlooked tactic towards championing energy efficiency measures.

Life Cycle Cost Analysis (LCA) is the “correct” way to measure the real cost of a measure.  It provides for the lowest cost approach over the lifetime of the measure.  LCA is typically most useful for complex or multi-faceted options such as VAV air distribution vs. a fan coil approach.  When more straightforward options are presented, ones that don’t necessarily warrant an LCA, we should present the cost-benefit as a return on investment or ROI and not a simple payback.

“If it’s not a 3-year payback I’m not interested”

Ever hear that one before?  Maybe it was two years, maybe four, but if you’re in the position of evaluating or implementing efficiency measures, I bet you have.  Every project is different and each has its own constraints when it comes to finances.  The developers for a new spec office building will probably stick to a very short payback period because they will either sell the building or want to leverage its equity in the next three to five years.  Unless they can recoup any additional cost via a higher selling price, a measure must pay back before the building is sold.

But in the case of owner occupied buildings such as hospitals, universities, public school districts, or affordable multifamily housing, the owner of the project is in it for the long haul.  They have a vested interest in the long term costs to operate and maintain their facilities.  Often, we hear the “payback phrase” from folks in this group of building owners / operators.  While I can’t say where they get the number of years from, I can say that I am very often surprised at how short a payback period is expected.  Let’s take a university project as an example.  ABC College is building a new academic building and they’ve allocated $20 million for the project.  Some guy like me joins the team and says, “Hey, if we look at this equipment and that type of system, and modify the controls this way, you can save energy.”   ABC’s project manager says, “Great, what will it cost and how much will it save?”  How the information is presented to answer that question can make or break the decision to implement efficiency.

Money (Photo credit: 401(K) 2013)

The project manager’s question could cause us to answer “120,000 kWh of electricity and 4,000 CCF of natural gas.”  The construction manager looks at the suggested changes and says, “That’s a $68,000 add to the budget.”  That is likely a non-starter even though it’s a 0.34% cost increase to the project.  We then regroup and note that the operating cost savings are worth about $17,000 per year.  The project manager takes out his trusty i-Gadget and figures it’s a four year simple payback (you don’t even need an app for that).  “Four years it too long,” he says.  Very often, that’s where the conversation ends.  How can we present that information differently to get a positive result?

Speaking the Same Language

Some of us geeks like to know how many kWh, kW and CCF or gallons of fuel oil we can save.  Most folks don’t!  Most folks are looking at dollars and I can’t blame them.  Dollars are the tangible thing we give to others for their time and products.  Sticking with ABC College for a minute, I would propose to the project manager that rather than looking at a $68,000 adder, consider the long term financial implications.  We often use a simple payback method as a metric to define the value of an efficiency measure.  This is flawed.  While a four year payback might seem a little too long, consider it this way:

Take that $68,000 and invest it in the stock market for four years instead of increasing the efficiency of your building.  Let’s assume you get a healthy 10% return and it reinvests and compounds annually.  At the end of four years you’ll have slightly less than $100,000 for a gain of about $32,000 or a return on investment (ROI) of 47%.  Hey, not bad at all!  Let’s use that same method to look at the value of the operational savings based on efficiency.  You save $17,000 per year, and at the end of four years you’ve saved $68,000[1].  Over the same four year period that’s an ROI of 100%, more than double the ROI you got on that healthy 10% return.  Or to put it a different way: you could invest  the $68,000 in the stock market and at the end of four years you will have earned $32,000; or you could invest $68,000 into your building and at the end of four years it will have earned $68,000. The efficiency measure now becomes a very hard opportunity NOT to take.

Mason’s Efficiency Restaurant (Photo credit: SeeMidTN.com (aka Brent))

Lastly, it is typically the case that the cost of an efficiency opportunity will often be partially offset by an incentive from the utility company.  We’ve seen our local electric utility support measures with as much as a 50% first cost incentive, which significantly impacts the positive financial benefits of the efficiency measure.

Going Forward

We have to accept that some construction projects are simply hamstrung by unrealistic budgets or unwilling owners.  In my experience, however, there is some wiggle room especially when a compelling case can be made from a solid, financial standpoint that efficiency measures are the best investment.  We energy geeks have a responsibility to learn the financial jargon and the processes by which the decision makers make financial decisions.  We cannot rely on the merits of efficiency measures to ensure their implementation.  We’ve got to make sound engineering decisions to increase building efficiency that can be supported by simple, meaningful financial analyses so the folks making the decisions can weigh the benefits of energy efficiency against other investment opportunities.

The post The Economics of Building Energy Efficiency appeared first on Building Energy Resilience.

I have been involved with hundreds of projects in one capacity or another where I’ve designed or commissioned HVAC systems. With only a few exceptions, it’s been my experience that ductwork is never installed exactly as drawn. Most of the time it’s close. Usually, this is due to a lack of coordination during design requiring in-field modifications or a lack of detail when it comes to equipment hookups. We all expect design engineers to have their designs perfectly coordinated and their equipment details to be exact. I was on the design side for more than 10 years and I can tell you that there is never enough fee or enough time in the design schedule for that to be a reality. Until that changes, we’d all better expect field modifications.

Cx Associates engineer Katie Mason inspects some ductwork.

Design vs. Installation

That being the case, we as commissioning providers have to pay close attention to the implications of those modifications. We typically spend a lot more time in the field than the designers (their budgets are shot by now, remember?) and so we have more opportunity to look for and identify the changes. Sheet metal contractors are experts at installing sheet metal, not designing it. They are great at making things fit but aren’t always familiar with how they’ve affected the system when they make changes. Almost all the time, these changes are made to get the ductwork to fit. Doing so adds elbows, offsets and odd transitions, all of which add pressure drop to the system. The installation happens once but the duct system will be in place for 20, 30 maybe even 40 years before it’s renovated. That’s a lot of hours of operation over which the additional energy required to overcome the added pressure loss can add up.

Modifications Over Time

Another thing to consider is how the system will be modified over time. While we can’t predict the future, we can minimize the impacts of future changes. One example is a hospital central air handler that we recently overhauled. The unit was built in the early 1980s and there were some less-than-ideal main duct transitions and connections to the AHU plenum installed. At the time, the ducts were all properly sized for the expected service and the additional pressure loss was reasonably low; I’d estimate something like 0.25 to 0.33 additional inches of pressure. Consider that this is a 200,000 CFM system and you can realize that that additional pressure amounts to about 13 kW of additional operating energy or over 113 MWh of energy (costing $13,500) per year (being a hospital it operates 24/7). That was in the early 1980’s. Over time, the various spaces in the hospital have been renovated and upgraded to modern standards and this adds load from equipment and increases airflow requirements to maintain higher air change rates.

(Photo credit: proforged)

Fast forward to today. Those fittings I mentioned earlier are now supporting a fair bit more airflow than they were designed for. A balancing contractor recently measured the pressure drop across two of these fittings, which happen to be in series, and found the loss to be just over 1.3 inches! OUCH! That means over 445 MWh of wasted energy (or $53,000!) every year.

Often, we make small changes without considering the long term, potential impacts. Simple adjustments during construction, often with little or no first cost increase, can be made to limit or eliminate those lasting, long term impacts.

(Note – the pressure drop and MWh increases are, in fact, proportional in this case because while this particular zone has been overloaded, others have had their loads reduced and the unit CFM has remained roughly constant.)

The post Design vs. Installation: Small Details Have Big Impacts appeared first on Building Energy Resilience.

Introduction

We receive dozens, probably closer to a hundred commissioning requests for proposals (RFPs) every year.  The quality, content and requirements are as varied as one might expect.  Jennifer Chiodo posted some thoughts on how one can identify quality commissioning services and I’d like to take this opportunity to suggest how one might develop an RFP for commissioning services.

Content

The California Commissioning Collaborative, Building Commissioning Association and ASHRAE all have templates you can use for commissioning RFPs.  When developing your RFP, it is important to read through the templates and require only the services you need.  I suggest including a “second tier” of services, those which could be beneficial or fill a need your facility might have but are not essential to your project.

Photo by Flickr user Judy **

How are you to know that your RFP will elicit proposals that are complete and offer the best package of services for your project?  My suggestion is ask a commissioning provider to help you.  Architects and engineers typically have an idea of what commissioning is and some have a very good idea.  I’ve seen RFPs however, even from the latter group, that ask for tasks and services that don’t offer the best value to the owner.  In addition, they often miss opportunities to add value at minimal additional cost.  A commissioning provider will typically be in the best position to advise you on what content and services required by your RFP will best serve your particular project.

Examples

• Terminal Device Sampling
  • A terminal device is simply anything that delivers heating or cooling to a space.  It could be a VAV box, a radiator, a heat pump, etc.  A very effective means of reviewing the installation and operation of similar terminal devices is to use statistical sampling.  Rather than visit each and every of the 45 VAV boxes in an office fit up, for instance, a statistical sample will identify the lion’s share of any installation and operational issues.  If sampled early enough, the installing contractor can correct any identified issues and won’t repeat them going forward.
  • I have seen a number of commissioning RFPs ask for “full commissioning” of all such devices.  While this approach is certainly valid for critical components, it adds unnecessary cost to the commissioning contract in most cases.
  • Sampling or “first instance testing” is common practice among MEP systems commissioning providers, as well as building enclosure commissioning providers, simply because it works and offers a best-value solution.

Photo by Flickr user NashvilleCorps

• Construction Phase Only Commissioning
  • Excluding any commissioning design phase involvement can seem like a financially prudent move.  After all, your design team knows what they’re doing so why do you need to pay for a design review?  Our firm’s Principal Emeritus, Tom Anderson, wrote about this in some detail so I won’t repeat it here, but in essence it comes down to the value that varied perspectives and experiences can bring to a project.
  • The cost of a comprehensive review will vary depending on the size and scope of a project, but in general the cost will be between $3,000 and $6,000.  While this is no drop in the bucket, it isn’t a running faucet either!  Consider these two recent examples where a review resulted in first cost and energy cost savings that well eclipsed the cost of the review.
    • Recently, on two separate projects we suggested obtaining pricing from alternate manufacturers.  On one, where it was on rooftop air handling unit (RTU), the savings was $10,000 in first cost, combined with established, local representation.  On the other, the entire building’s HVAC system and components were sent out for budget pricing and the budget from a manufacturer with an equivalent product line identified the possibility of over $100,000 in first cost savings.  Both paid for our review fees more than twice over (the latter, if realized during the bid process, will pay for our entire commissioning fee almost twice).
    • We consistently identify efficiency opportunities that save energy, often resulting in cost savings to the owner that pay for our review fee in less than one year.  In Tom’s post noted above, he used the example of a pump.  On a recent project, where the design team included constant speed pumps (which met code) we suggested a change to variable speed pumping for all the reasons Tom noted.  The suggestion was accepted, and once balanced, the pumps drew 9.9 amps to meet the balanced pressure differential set point even though they were designed to draw 27 amps.  These are 24/7 pumps, wired at 460 volts.  Doing the math, the annual operational savings is almost 120,000 kWh equal to over $14,000 per year.  One measure that paid for our review fee 2 1/2 times over in the first year.

Conclusion

When developing your RFP for commissioning services, consult with a commissioning provider you trust.  If you don’t know one, ask your A/E team for a few names and talk to them first.  Having firsthand, practical knowledge of the process of commissioning and the ability to walk you through the potential benefits of each step will allow you to write an informed, meaningful RFP that you can be sure will meet the needs of your project without excessive scope and the associated excessive fees.

The post Tips on Developing an Effective Building Commissioning RFP appeared first on Building Energy Resilience.

Introduction

In my last post I cited three examples of incomplete or incorrect control programming that all would have had negative effects on building operations or equipment life expectancy. In this post, I want to focus on one piece of equipment, a rooftop ERU (energy recovery unit) and, more specifically, on the graphic page for that ERU.  This is another prime example of the controls not being done even though the contractor had said they were complete.

The “Finished” Graphics

Below is what the building operator saw when they logged on to their brand-spanking new BMS system.  I’ve added the red numbers to highlight some of the issues we found.

Rooftop ERU Controls Graphic Showing Several Issues.

1. There is no indication of wheel bypass damper positions.
2. There is no indication of the exhaust damper position.
3. There is no indication of the heat recovery wheel, command, status or speed (this wheel is driven by a VFD)
4. The supply fan command is on but the speed says 0.0% and the supply fan amps read 8.7A.
   1. The fan speed might represent the command, not feedback, in which case the controls may be sending a 0% speed command which then causes the VFD to run at its internal, minimum speed.  This would cause the amps to show up at some value other than 0.0 (because the fan might actually be running).
   2. Note that this indicates a real operational issue, namely that the return air flow is over 12,000 CFM, but the supply fan is barely running.
5. What does it mean when the reversing valve is off?  It should either read “heat” or “cool”.
6. The Low Temp reading is “????”.
   1. This is a low limit or freeze stat.  Maybe this is a bit picky, but it should say “low limit” or “freeze stat”.
7. The leaving conditions off the wheel should be in degrees F and % RH.
8. The Iso (isolation) Damper is shown as “On”.  Dampers are either open or closed or X% open, not “On” or “Off”.
9. What does the “Iso Pressure” represent?  Is this the pressure across the damper?
10. The condenser water valve is 100% … open or closed?
11. There are no units associated with the Zone Temp & RH.
12. If the return air is 73.7 degrees F and 14.3% RH, there is no way the zone is 50% RH at 72 degrees F.
13. 15% is the minimum position … of what?
14. This is a graphic of ERU-2.  It is connected to ERU-1 via ductwork for redundancy.  There should be a link to the ERU-1 graphic page where this text is.
15. Cool/Heat mode is shown as “100%”.  It should read “cool” or “heat”.
16. High Static is “normal”.  This is good, but what’s the setpoint?
17. The return air static pressure is shown as 0.546 inches of water.  It’s under a suction from the exhaust and supply fans.  This should be a negative number.

I wanted to use this example to illustrate what happens when the contractor is rushed and doesn’t have the time to properly QA his work.  This ERU was just one of dozens of large pieces of equipment controlled by this BMS system.  They ALL exhibited similar issues.

In my last post I noted how controls are the very last thing to be done for an HVAC project and most of the time the contractor is rushed and expected to do more work than possible in a very short time.  I think this one screenshot illustrates that point very well.

Finish Line (Photo credit: jayneandd)

Getting Across the Finish Line

We know the pace of construction isn’t about to change. So what can be done to make sure the controls are done when they’re supposed to be?  One way to ensure the controls are done correctly might be holding the contractor accountable with interim deliverables.

Typically, after the controls contractor has his or her submittal approved, there is no more documentation required.  Why not require a submission of the graphic pages that will be used?  While this won’t address issues like #6 above (the Low Temp reading “????”), it will likely identify the majority of the rest.  The changes are simple; they can be done in the contractor’s office and no interruption of a functioning controls system is required to implement the changes.  In addition, every controls company has an emulator through which they can run controls programs to simulate how they work.  I’ve reviewed complete programming on simulators and have been able to identify potential operating issues before they were implemented.

Team work is essential to each project. Cx Associates strives to work in a collaborative fashion to ensure a successful project. We encourage all the members and leaders of project teams to use extra care before turning over the controls of a building, making sure they are done, and done right.

The post The Building Controls Are (Not) Done – Part II appeared first on Building Energy Resilience.