Solar Decathlon: Not So Sunny, But Full of Energy!

October 19, 2009 / no comments

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Interior honeycomb shades provide privacy and additional insulation, and are a part of the nighttime ambient lighting system in Team Boston's house.

I was fortunate to be able to spend the weekend visiting the Solar Decathlon houses on the Mall in Washington, D.C. (see the Solar Decathlon website and Amber’s last blog article “Curious” About Sustainable Design?).

Miserable weather meant that the houses weren’t generating much electricity, but the energy produced by the students attracted many people like me willing to stand in long lines in the rain and mud to see their work. I was impressed by the sheer immensity of what the students had accomplished (none more so than the Lam-sponsored Team Boston!) and the many ways in which each team solved the same sets of design problems. It was fascinating to see how they balanced the tensions between having to make a highly efficient house that also functions well, would be a nice place to live in, and is beautiful. You could see the compromises: the house that was super-insulated but didn’t have many windows, or the house with large south-facing windows but no architecturally integrated shading to block the summer sun (perhaps because it would have violated the purity of the architecture) – or the house that kept the lighting energy so low that the lighting quality suffered.

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Team Boston's southern façade featured an integrated shading overhang and innovative roll-up exterior louvers for no summer solar heat gain.

But the thing that struck me most about the competition was not something I saw on the Mall, but an entry in Thursday’s Daily Journal on the Solar Decathlon website. In describing the winners of the Lighting Design competition, it said: “A Minnesota team member commented that their goal was to use only 500 watts (or the equivalent of five incandescent light bulbs) to light the entire house”. Now, I appreciate the attempt to make the information accessible to the average consumer, but this comment is so telling about the incorrect way that the world considers lighting energy efficiency.

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This type of vanity mirror seen in Penn State's bathroom showed up in a few other houses, too. Love the skylights!

The Solar Decathlon is a contest that measures (among many things) energy-efficiency, not total watts. Energy is Watts x Time (see my blog article Fight the Power! ) So I could have 2,000 watts of total lighting in my Solar Decathlon house, but if I only needed to turn some of it on for a small amount of time each day, I could use less energy than a house with 200 watts of total lighting that had to have all the lights on most of the time. If they only measured watts at the Solar Decathlon, then all they’d need to do is hook up the houses to a meter, make them turn on every system and appliance, and the house with the lowest wattage would be the winner. Well, that would be easy – but it would be dumb. So why, then, do we talk about lighting performance this way?!

So there I was on Saturday in one of the houses and a charming student tells us that all their lighting uses only 200 watts. Sigh. And then later that afternoon, in another house a student tells us how their LED fixtures use just 3 watts each. Arrgghh. So OK, we’ve done a bad job educating our students about how to measure lighting energy efficiency, but this also brings up another timely issue: lighting quality. What if you only use 200 watts but lighting quality is poor?

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Finelite's LED task lights provide great bedtime reading lights for Team Boston.

And then, as expected, the LEDs were everywhere along with the hype. Several houses proclaimed that all their lighting was LED, as if just saying that indicates some special level of energy efficiency. And of course, as we were told at one house, “LEDs are seven times more efficient than an incandescent light”, when realistically they are maybe half that. Where do they get this stuff? And it’s not just efficiency misinformation, but the lighting quality issue too. Far too often, the LED sources that I observed were glary and had a ghoulish cool color. If the Solar Decathlon is a predictor of trends in residential lighting, then we might conclude that we have a lot of glare in our future.

Another comment I overheard that I thought was telling went something like this, from a gentleman standing below one of those glary LED accent lights: “Gee, if we could only get LEDs that were good for ambient lighting”. I almost went up to him and said, “You have a much better source already – linear fluorescent – twice as efficacious as LED, and much less expensive.” But I kept my mouth shut and wandered out into the rain and mud thinking that we Lighting Designers have to do a much better job educating students and the world about how to achieve true lighting energy efficiency and lighting quality.

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Some serious lighting bling from Team Germany.

Photos Credit: Glenn Heinmiller / Lam Partners Inc

“Curious” About Sustainable Design?

October 5, 2009 / no comments

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A local group of students from the Boston Architectural College and Tufts University are more than just curious. These students have combined creative efforts, engineering skills, and a shared passion to jump-start a wave of curiosity in others; Team Boston was formed to propose, design, and build an actual solar-powered model home. The Curio House took on its motto, “live curious”, to inspire others to seek out energy-saving, sustainable architecture.

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Curio is Team Boston’s entry at the upcoming Solar Decathlon, an internationally recognized biannual competition that works to promote, educate, and foster sustainable innovations in building technology. The competition is sponsored by the Department of Energy and the National Renewable Energy Laboratory. It calls for student groups to build a solar-powered house that will compete in ten categories. The house will be evaluated on its overall energy performance in simulated “daily living” scenarios, on the basis of the quality of its architecture, market viability, engineering, lighting design, communications, indoor comfort, hot water production, appliances, home entertainment, and energy production/consumption through net metering.

The construction site at Tufts University has enjoyed enthusiastic support from other local students, professionals, and community members. Inspired by the students’ bold efforts, and by the innovative nature and challenge of the project, Lam Partners has proudly sponsored Team Boston in their quest for the most energy-efficient solar-powered house at the Solar Decathlon on the National Mall in Washington, D.C.

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Over the past couple of months we have had the privilege of getting to know and work with some of the dedicated and high-spirited members of Team Boston to help refine and execute their lighting design goals and strategy. We supported their efforts through computer modeling, mock-up studies, and fixture selection advice, and by arranging generous donations from lighting manufacturers. We’ve collaborated with the team to realize a lighting design with high aspirations for the competition.

Curio takes advantage of many energy-saving, green technologies, such as passive solar design, daylighting, a solar thermal hot water system, and a photovoltaic panel array to generate the home’s electricity. The energy-conscious electric lighting system takes advantage of efficient fluorescent and LED fixtures, occupancy sensors, and dimming to further reduce energy use while enhancing occupant comfort.

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The lighting portion of the competition focuses on the quality of a functional, efficient, pleasing lighting design. The lighting concept for the main living space expands on the idea of the house as a central space with a lot of user flexibility. The main ambient light is provided by linear LED fixtures concealed in architectural coves that define the perimeter. There are also several instances of task lighting provided throughout the main living area to accommodate various user needs.

Lighting at the exterior is minimal, with LEDs providing soft, appropriate light levels on the ramp surfaces for wayfinding, and LED downlights to highlight the entries. The exterior is lit exclusively with LED sources to minimize energy consumption. This strategy is used to emphasize the energy savings, as well as to enhance the overall perception of the lighting technologies employed throughout the design.

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The house is also engineered in such a way that it can be disassembled, transported, and reassembled for competition. Currently Team Boston is disassembling the house and heading to Washington D.C. to finish construction, compete, inspire curiosity, and exhibit their hard work, from October 8th through the 16th.

The Curio House is a great example of learning, refining, and implementing energy-efficient strategies within daily home life. As part of the continuously evolving “green design” movement, the project defines and proposes viable building solutions for sustainable living, such that the future of the house itself is also evolving.

After a rigorous and exciting cycle of competition in D.C., the house will find a permanent home on Cape Cod as one of the first structures in a new green housing development, where it will be able to live out and expand upon its green foundation and ideals. To follow the progress of Live Curio, throughout the competition and beyond, check out the website at http://www.livecurio.us/.

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Image Credits: Team Boston (1, 4, 6); Allison Fisk (2, 5), Glenn Heinmiller / Lam Partners Inc (3)

Why Light It?

September 28, 2009 / no comments

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Light pollution and light trespass are hot exterior lighting topics, and they both relate directly to the broader topic of energy conservation. Simple logic tells us that shooting light into the night sky, either directly or inadvertently, is basically a waste of light and energy. The light that escapes above the horizon hits nothing but air, water, and smog. Some of that light is reflected back down as light pollution, that eerie yellow glow that obscures the stars, but none of it is useful – it’s an unutilized byproduct of the artificially illuminated environment.

That’s not a good thing! Sky glow and light trespass have been linked to problems like sleep disorders, migratory bird death, and obstruction of the night sky. Small problems that may seem insignificant? Well, think of it this way: sky glow exposes how much energy and money we pump into the air, and guess who pays for all that extra light – you, the taxpayer! Millions and millions a year, and most of it is powered by fossil fuels.

Can we simply turn off all the exterior lights then? No, unfortunately, the lighting was probably installed in the first place to serve a purpose: the lighting of streets, buildings, parks, and other places that people navigate to at night.

Could we reduce the amount of exterior lighting, though? We can already discern that a lot of lighting is wasted in the sky. Could it also be possible that we’ve intentionally lit that which should not or need not be lit to begin with – that the purpose served was not a legitimate, well-conceived purpose? Absolutely!

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Since the invention of the light bulb, we’ve been putting electric lighting EVERYWHERE. We did it because we needed it and wanted it, to see where we were walking and driving (street lighting), to see where we were going (sign lighting), because it looked nice (decorative lighting), to show off our accomplishments (building and bridge lighting), to illuminate nature (tree uplighting), and for security and safety (the former as a police control measure and the latter as a matter of perceived personal well-being).

Now some designers are taking another look at the “why” of design, questioning whether or not we really need all that lighting. Do we need to light a stretch of rural highway when we have headlights on our cars? Do we need to light city centers to 50 lux (5 footcandles for you Imperialists) when 20 will do? It’s not just a question of yes or no, but also of how much.

To take a few of these examples, here are some issues that we should think twice about:

  • Street lighting – do we need to light roadways so much that we can do without headlights entirely? (I’ve seen it – no headlights! Insane!) Perhaps we can use the task-ambient approach here: ambient from very low-level street-based systems, and task from headlights. We’ll still need to pay attention to the vehicular-pedestrian intersections but all that lighting in between could possibly be reduced.
  • Sign lighting – do you really need to light your signs all night long, from the bottom shining up? What if you turned the sign off after midnight, and lit it from above?
  • What about building lighting? Many developers, architects, and designers want to see their projects as the beacon of the neighborhood. Uplights graze the columns, floodlights slam into concrete walls, and twinkly lights adorn the penthouse. Should every building do this, though? Are they entitled to? What if the desire to be the best on the block simply precipitates escalation of building lighting – where does it end? Everyone needs to ask themselves “Should I even light the outside of this building?” That goes for public monuments, too; maybe we should take public money used for lighting public monuments and put it somewhere more useful, like healthcare. How about focusing on the entry and letting the rest go dark at night?
  • How about landscape lighting – why? We light the trees and shrubs only because we can. Yes, it does look pretty, but at what expense? The amount of light the canopy of any particular tree can catch in comparison to what shoots straight into the sky is very little.
  • And finally, lighting for security and safety. This is a very sensitive issue. Police officers, emergency response professionals, and the general public would prefer more light as opposed to less. The popular opinion is that more lighting equals less crime and, while more light will certainly help the police in identifying perpetrators, it doesn’t necessarily create safe environments. There are very well-lit alleys in which all sorts of crimes happen. The statistics have too many variables to pin down an unquestionable correlation. Maybe we should concentrate on good quality lighting that serves these purposes without increasing light levels. Better lighting, not more!

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All of these applications are only marginally effective, which supports the position that we simply do not need as much lighting as we have. If a total of three people drive by a building at 3:00 a.m. and see it lit up, is keeping it illuminated all night long worth the collective fifteen seconds of viewing?

Every developer, architect, or designer should question if it’s really worth it. But then, it’s a hard question to ask – who’s to say what qualifies and what doesn’t? Who will speak up and tell someone “no”?

Photo Credits: Liber (1), Ian Plumb (2), Clav (3)

Daylighting Through Building Weight Loss: Thin Your Way to Sustainability

August 24, 2009 / no comments

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Ever been in a building so big that you can’t see a window or what’s going on outside?

A lot of modern buildings are so big, fat, and wide that you can get lost in their bowels and, unfortunately, those depths can’t function without the help of electrical or mechanical systems. They’re on life support, so reliant that a venture into the interior spaces is impossible without power. We’ve been designing caves!

Long gone are the days when architects and master builders had to rely on natural ventilation and daylight to make their buildings inhabitable without a torch. There may be a light at the end of the cave, though. Recent sustainability efforts like LEED, among others, are seeking to reintroduce some of these design elements for one reason or another, but they’re always optional, and the guidelines lack teeth.

Until recently, it has been cheaper to pay for electricity and gas over time than to pay more up front for a building to use less energy. That’s going to change soon. President Obama’s plans to increase energy efficiency and reduce fossil fuel consumption over the next twenty years is very ambitious. At first glance, it almost seems impossible to get to zero percent net energy use by 2030. Some of those goals can be met with renewable energy sources, onsite or off, but the rest of the savings will need to be made up by simply cutting the energy we use. How? Can you look around your office and pick out what you can live without?

In the past, would-be building owners sought the best buildings to suit their needs for the least money. But are building designs and costs truly independent of sustainability and conservation factors? It usually costs more, however slightly, to build something that’s more environmentally responsible, whether for better-quality materials or for the design expertise to put it all together. So, what doesn’t show up as a cost of building instead takes on a long-term cost on people, resources, and the environment. Some of that deferred cost has already come back around, hence the sustainability movement.

Now, economically and geometrically, the cheapest typical building shape that best utilizes open space is one that looks like a pancake or cube. Any other shape and you could end up spending more on the skin, structure, and support systems. The core of thinner buildings takes up more of the floor plate per floor and ultimately, less space is available per dollar spent. Owners also like to maximize the building footprints on their land, oozing to the edges of the plot and thickening the building. So, the tendency and enticement to ‘fatten up’ a building persists.

Why, then, do we want thinner?

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One problem with the fat design is that there is no opportunity for natural airflow. Interior walls and the sheer breadth of the floor plate are not conducive to promoting airflow from one outer wall to another. Mechanical ventilation is introduced without any further consideration, and it takes on the role of breathing for the building. Mechanical ventilation = energy use.

Daylight, too, is proportional to distance from windows (skylights are great but only for the top floor). Without daylight delivery integrated into the façade design, the effective daylight zone is about twelve to fifteen feet into a space. With lightshelves or other daylight redirection devices, you can potentially get up to thirty feet into the space. So generally, a building any wider than sixty feet can’t fully take advantage of natural lighting. No available daylight = electric light = energy use.

Building energy use varies by building type and location, but the four major energy sponges are heating, cooling, lighting, and plug loads. Let’s assume that we won’t be giving up refrigerators or computers anytime soon, so our plug loads are here to stay. That leaves the big three – heating, cooling, and lighting – which we have the least control over as occupants, and the most impact on as designers. By designing our buildings to passively take advantage of heat, light, and air from outside, we can rely less on the electricity-based systems we use to force life support into the centers of our caves.

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Ask yourself: “Will my building be able to function if we run out of, or are not allowed to use, electricity or gas?” The answer should be yes!

Are there any other reasons for thinning up our buildings for natural ventilation and daylight? Three great ones: these energy sources are free, readily available, and are products of the environment instead of an impact against it. As lighting designers, we can confidently say that the most energy-efficient electric lighting is the kind that is turned off.

Photo Credits: Dagbrown (1); Global Jet (2); Mark Sebastian (3)

Fight the Power!

July 20, 2009 / no comments

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Compliance with energy codes has become a regular part of the design process for lighting designers in recent years. Prior to the release of the 2004 version of the ASHRAE/IES 90.1 standard for energy codes, it was easy to design lighting without worrying about bumping into code limits. This was because codes had not yet caught up with energy-efficient technologies and current design practices. The ASHRAE 2004 standard was significantly more stringent in its limits on the total amount of connected lighting load allowed. It is still possible to produce quality lighting design under these limits, but much of the headroom went away. Frankly, you can’t be sloppy anymore, and this is a good thing. So, less energy use, more code compliance work for lighting designers – happy ending, right? Well, maybe.

Let’s look at the structure of U.S. energy codes as they apply to lighting. They aren’t really energy codes, they are more like power codes. The main way that U.S. energy codes regulate lighting is by limiting the amount of power (watts) that your lighting system can use. This is done by giving you allowances for maximum lighting power density (LPD), measured in watts per square foot, for various building or space types. In other words, the amount of power you can draw with every light in the building turned on at full output – but it is the rare building that has every light turned on 24/7.

Energy = Power x Time, so an energy code needs to take power (watts) and time into consideration. This is why we pay for electrical energy by the kilowatt-hour (energy), not by just the total wattage of all the devices connected to the meter (power). To be fair, current energy codes do have provisions that address the time variable of the equation – but they only do it by requiring automatic controls to shut off the lights when not needed. There is no quantification or metric of what those controls get you in energy use reduction. A building with lights on 20 hours per day is treated the same by code as a building with lights on 10 hours per day. A building with the most rudimentary code-minimum controls is seen as identical to a building with sophisticated occupant-sensing and daylight-responsive controls.

We can see why lighting power as the metric for building lighting energy-efficiency is deficient, but is this a big problem? Yes, and here is why: energy use of our buildings must be reduced radically – the push to do that by improving the performance of envelope, HVAC, and lighting is strong and growing stronger, and rightfully so. For example, the energy bill working its way through Congress, at 1,000-plus pages, contains a section to institute energy codes enforceable at the Federal level with a target of 55% energy reduction (over the 2004 code baseline) by 2018, and 75% by 2030. Serious stuff! So when looking at lighting, the obvious thing is to just keep reducing the lighting power allowances, right? Wrong! The use of more efficient lamp and fixture technologies alone can’t achieve these targets. If we just keep pushing down power allowances, lighting quality will suffer and we will find ourselves sitting in dark rooms or bland white rooms lighted with bare, glary light bulbs. To truly reduce lighting energy use we need to figure out a way to write a code that actually regulates lighting energy, not lighting power.

Photo Credit: Isaac Bowen

What’s “Efficient”?

July 13, 2009 / no comments

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Today we’re barraged by claims of “efficient lighting” or criticisms of “inefficient lighting”, but what does that actually mean, or what should we actually be concerned about as designers?

In casual terms, we think of “efficient” lighting as using less energy to produce a given amount of light, or as producing more light for a given amount of energy. Technically, the term used to relate visible light produced to overall power consumed is “efficacy”. This is typically expressed as the ratio of visible light to electric power, or lumens per watt. But for practical purposes, efficiency means providing the useful light we seek for as little energy consumption as possible. Useless or wasted light doesn’t count. Or even more importantly, it should mean satisfying our visual needs using as little energy as possible. And that can’t be measured with a light meter.

With today’s emphasis on energy-efficiency, too often evaluating “efficiency” based strictly on light meter readings (or on calculated predicted meter readings) results in visual environments of poor quality. So the key question we need to ask about efficiency is: “efficient at what?” A bare light bulb hanging in your living room could be very efficient at registering on a light meter, but very inefficient at creating a comfortable visual environment.

If we do limit ourselves to what can be measured with a meter, for architectural lighting there are really four components to efficiency:

Lamp efficacy: how much visible light is our lamp (“bulb”) producing for each watt of electricity?

Control gear efficiency: with the exception of incandescent (including halogen), all modern light sources require some electrical components to get the lamp started and to provide the proper operating voltage and current. These ballasts, transformers, and LED drivers consume energy, sometimes a lot of it – they can use 10% or more as much energy as the lamp they serve. So we need to include this energy consumption in the overall lighting efficiency evaluation.

Luminaire efficiency: rarely does all the light from a lamp manage to get out of its light fixture. There are almost always shields, reflectors, lenses, etc. to shape and baffle the light output, and these block some of the light from escaping. Luminaire efficiency can range widely: for a good linear fluorescent indirect-direct pendant it might be over 90%; for a good compact fluorescent downlight it hovers only around 50%. (One of the advantages of LEDs is that, although their efficacy is not particularly high, because LED light output is intrinsically directional, luminaire efficiencies can be higher for direct, controlled beam applications).

Utilization: related to the antiquated “CU”, or coefficient of utilization, this is basically the fraction of light coming out of a luminaire which actually ends up doing something useful – lighting a surface we want to light. A good (or rather, bad) example is the typical dropped-lens cobra-head streetlight. What we want to light is the roadway and maybe the surrounding area or sidewalks. But, as anyone who has ever looked out of an airplane window knows, an awful lot of the light from cobra-heads goes right into the sky. This isn’t useful (in fact the opposite), so it doesn’t count in the “utilization” coefficient.

So we need to multiply all these four factors together to get even a simple numerical evaluation of a lighting system’s “efficiency”. There’s also a fifth, very important factor affecting energy use: controls – the most efficient light can be the one that’s turned off when it’s not needed.

But lastly and very importantly, we need to consider whether a good design can achieve an equally good, or better, visual environment while registering “less” on the light meter. There is no question that this is possible – it happens all the time. A study by the GSA of recently completed federal courtrooms (see link below) found that measured light levels had little to do with actual user satisfaction with the lighting. As another example, an environment with a substantial indirect lighting component can have lower measured light levels while actually providing better visibility and a greater sense of brightness and comfortable seeing. So let’s design for true efficiency: satisfaction per watt.

GSA COURTROOM LIGHTING CRITERIA EVALUATION AND ENERGY USE STUDY

Photo Credit: SwamiStream

Making the Sausage

June 14, 2009 / no comments

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You’ve heard the saying, “There are two things you will never wish to watch: the making of sausage and the making of legislation.” As the new chair of the Energy and Sustainability Committee of the International Association of Lighting Designers (IALD), I’ve been getting a glimpse into the kitchen.

Why, you might ask, would a Lighting Designer care about the making of legislation? Energy codes, light pollution ordinances, LEED, green building codes, Federal energy efficiency legislation, Department of Energy rulemaking, and on and on. Get the picture? All of these things affect our work as lighting designers, directly or indirectly.

Lighting Designers have a responsibility, and an obligation, to minimize the negative environmental impact of their design decisions. Mostly, this means energy! energy! energy! Making lighting more energy-efficient is the easy part. The hard part is doing it without destroying the quality of the visual environment – this is what we do.

So, back to the sausage. We get involved with the development of energy codes and standards and legislation to make them the best they can be. Don’t get me wrong, this isn’t about resisting or trying to make standards more lenient. This is about maximizing real energy savings while simultaneously maximizing lighting quality – no simple task. Too often, standards have been developed by people who do not understand this balancing act. A belief that simply limiting the available watts or setting efficiency standards on equipment is enough can lead to unintended consequences, such as the obsolescing of unique equipment, or increased glare and light pollution.

The energy bill winding its way through Congress has an outdoor lighting energy efficiency provision that is being negotiated by lighting manufacturers and environmental groups. Our committee has been following this process and making ourselves heard (see IALD position statement below). We provide an independent voice that understands how to reduce lighting energy use of the total lighting system and how to create quality luminous environments. You need to understand this if you are going to write an effective standard, right? This is what motivates me to watch, and sometimes help, make the sausage.

Photo Credit: Stephen M. Lee

RELEASE IALD POSITION STATEMENT OUTDOOR LIGHTING.pdf