Navigant Research Blog

California Calculates the Value of Time in Energy Efficiency

— July 22, 2014

The 2013 update to California’s Title 24 building energy efficiency standards went into effect on July 1, 2014.  In addition to increasing overall building efficiency requirements over the 2008 standards, this update set out more stringent lighting requirements for both residential and non-residential buildings.

The 2013 update also includes changes to California’s time dependent valuation (TDV) calculation.   Used only in California, TDV is a tool to gauge the value of energy efficiency measures.  Unlike other metrics, such as site or source energy (measured in kBtu), TDV includes the cost to provide energy based on time of use, as well as other variations in cost due to climate, geography, and fuel type.

TDV was developed in 2005, and was updated in both 2008 and 2013, to help California meet the energy efficiency goals established in Title 24.  In the 2013 update, the California Energy Commission (CEC) changed the TDV calculation to account for climate sensitivity by separating California into 16 different climate zones.  This alteration helps reflect differences in energy costs driven by climate conditions, which vary considerably throughout California.

Finer Grained

One of the key barriers to wider TDV adoption is developing values for each climate zone.  As stated above, California alone has 16 climate zone values.  Another limitation is that many state officials are unaware of it: California is the only state that uses TDV, whereas metrics such as site and source energy are much more commonly employed both nationally and internationally.  Further, TDV does not account for the potential grid modernization costs necessary to export excess electricity back to the grid.

But since TDV accounts for differing energy costs based on a range of factors, it more accurately captures the societal cost of energy consumption that’s missed in assessments based only on source or site energy parameters.

In the coming years, as California tries to build more zero energy buildings (ZEBs), TDV will play an important role in determining whether a building meets the required energy use intensity to qualify as zero net energy.  The forthcoming Navigant Research report, Zero Energy Buildings, will provide an update to the 2012 iteration, and look further into the benefits and challenges associated with TDV as a metric.

 

In New York, Greening Older Buildings

— July 21, 2014

Building energy efficiency has reached the mainstream.  Clean energy technologies have become so common that technical training in renewable energy and energy efficiency retrofits is becoming more and more accessible.

Green City Force (GCF), a Brooklyn, New York-based non-profit, has trained nearly 300 young adults living under the poverty line in NYC for careers in the green economy with the group’s Clean Energy Corps.

The Clean Energy Corps supports a variety of projects related to energy and efficiency, including energy audits in low-income homes, urban agriculture, and energy efficiency retrofits.  The corps provides its members with an academic and technical training program to prepare them for college; the program leads to certification for entry-level work in energy efficiency and includes GPro, a nationally recognized certification in building science.

Retrofitting

One of the major partners for Green City Force, and for the Clean Energy Corps specifically, is the New York City Housing Authority (NYCHA).  More than 8.4 million people reside in New York City, and 615,199 of them are served by the authority’s Public Housing and Section 8 programs.  This represents 7.4% of the population of New York City.  Together, both programs cover 12.4% of the rental apartment stock in one of the most expensive cities in the world.

The Housing Authority’s property portfolio is equally impressive and rivals commercial housing developers.  The NYCHA oversees 334 developments, including 2,563 buildings and nearly 178,000 apartments.  In contrast, the Chicago Housing Authority has 21,000 apartments in 128 properties.  Los Angeles has 2,491 apartments across a portfolio of 93 properties.   Only 20% of the developments in NYCHA’s portfolio are less than 30 years old, and one-third of the authority’s developments are more than 50 years old.  Modern buildings are built with energy efficiency in mind, but older buildings have more room for improvement.

The More the Better

GCF develops service projects in partnership with the Housing Authority, city agencies, and other non-profits.  One example is the Love Where You Live Challenge, which bring corps members together with fellow NYCHA residents to reduce energy use in homes.  Corps members gain experience and skills, while the Authority reduces its energy costs.  NYCHA spends $535 million annually on utilities.

The NYCHA is not the only public agency using innovative approaches to promote energy efficiency.  The Washington Metropolitan Area Transit Authority (WMATA) recently awarded Philips Lighting a 10-year lighting performance contract to upgrade lighting across 25 parking garages to LED lighting.  Instead of paying out of pocket for the 13,000 fixtures, WMATA will share the savings in energy costs with Phillips over the 10-year period.

For disruptive technologies such as energy efficiency, the more business models in the market, the more accessible the clean energy economy becomes.

 

Ending the Office Climate Wars

— July 17, 2014

For some commercial building tenants, interacting with the heating, cooling, and lighting of their offices has been a challenge.  There are the dummy thermostats, the inoperable windows, the buildings that are running heating and cooling at the same time, and the hot and cold calls from the corner office.

Many cubicle dwellers use space heaters in summer to keep their overly-cooled selves from shivering, while others need fans to mitigate afternoon sun – even in the winter.

Improved automated buildings controls, networked light sensors, occupancy sensors, and re-commissioning have all helped office workers be more comfortable in their workplaces.  Yet, the overarching problem remains.  This is due in part to the challenge of keeping old and complex system running optimally.  The other challenge gets back to the dummy thermostat: You can’t keep all people happy (or warm, or well-lit) all of the time.  It’s no simple matter to gain an understanding of people’s comfort levels and equip a building to serve those different and diverse needs.

My Chair, My Climate

The University of California Berkeley’s Center for the Built Environment (CBE) has led a number of research efforts that try to determine how comfortable we are when sitting at our  desks.  CBE has developed prototypes of office chairs that incorporate user-controlled fans and thermometers.  These climate-controlled chairs, known as Personal Comfort Systems, aim to take some of the balancing load off the HVAC system.  A one-degree expansion of a building’s deadband (the temperature range where HVAC systems do not have to heat or cool) can result in energy savings reductions of 5% to 15%.

CBE also conducts regular occupant surveys in buildings of all kinds.  One recently found that occupants of LEED-certified buildings feel no more comfortable than those in buildings that lack the LEED plaque.  One interesting observation is that, over time, LEED-occupied people report less and less comfort.  Perhaps there’s a honeymoon period for green buildings when people seem to feel more comfortable.

The Goldilocks Strategy

For some occupants, the proximity to windows is an attractor, while others find the glare and the heat disruptive.  The smart glass company View has created a mobile application that enables users to remotely control their windows’ opacity from their desks.  The app allows a user to schedule tinting depending on personal need – for instance, when it’s time to wake from an afternoon nap.  For more on smart glass, see Navigant Research’s report, Smart Glass.

Meanwhile, a startup called Building Robotics is attempting to solve the collective comfort puzzle using an algorithmic technique.  Its innovative occupant comfort product, called Comfy, asks users to rate their comfort simply: too hot, too cold, or just right.  Comfy then tunes a building’s HVAC system to deliver maximal comfort based on occupant feedback instead of predetermined setpoints.  Using machine-learning algorithms and facility management guides, it can create user-focused HVAC schedules based on what feels good to most users, not what temperature air is being delivered.

Comfy will likely prove to be a disruptive technology, reducing the engineering focus on setpoints and increasing the striving for customer satisfaction (i.e., comfort).  As these types of technologies spread, office workers will be more comfortable; and in serving them, buildings will use less energy.

 

Li-Fi Turns Light into a Data Stream

— July 13, 2014

Since Harald Haas demonstrated the ability of light-emitting diode (LED) lights to transmit data during a TED Talk in 2011, the promise of Li-Fi (short for light fidelity) has received a lot of attention.  As researchers develop faster and faster communication speeds, the application of the technology to the building space appears both realistic and attractive.  Commercially, General Electric (GE) has demonstrated the viability of the technology through its launch of LED-based communication for retail environments.  Li-Fi could be cheaper and consume less energy than existing wireless communication technologies that rely on radio frequencies (RF).  Smart buildings, which require a dense and flexible control network, present an interesting application for a Li-Fi deployment, particularly with the increased adoption of LED lighting.

Non-Interfering

Li-Fi seems to be a compelling alternative to the RF technologies that are currently in use today.  First, the RF available to building automation is crowded.  Moreover, as the Internet of Things becomes more pervasive, more and more communication nodes will further saturate the environment.  RF travels through walls.  So, a node in an adjacent room will be competing for detection.  But Li-Fi is impervious to this problem.  Since the range of any individual Li-Fi node extends only to the nearest wall, the communication in one room will never interfere with other communication in a different room.  In other words, the inherent limitations on Li-Fi range are an ideal solution for saturated networks.  Moreover, more than just crowding, interference from microwaves and other devices can be a problem, particularly in medical environments.  Li-Fi is immune to RF interference.

Security is another area of concern for wireless communication.  It’s relatively easy to hack a Wi-Fi network.  Li-Fi, on the other hand, has a shorter range and requires line-of-sight.  As a result, it is inherently more secure.  You have to be within the range of the transmitter and receiver, shifting the threat of IT security to more manageable physical security.

The Bad News

The technology faces some serious technical challenges before widespread adoption, though.  In addition to enhancing security, the line-of-sight requirement also presents challenges.  Though Li-Fi is immune to RF interference, it is susceptible to interference from a more ubiquitous source: the sun.  Receivers placed close to windows could be rendered ineffective.  Additionally, lighting in buildings is typically designed to be unidirectional, from the light source to the space to be illuminated.  But communication networks must be bidirectional to both send and receive data.   In order to create a Li-Fi network, lights would need to be installed to point at each other, which is at odds with their intended functionality.

Despite these drawbacks, Li-Fi could overcome several of the barriers facing wireless.  Though most of the current buzz focuses on visible light communication, using infrared light could solve many of the hurdles.  Windows can be designed to block infrared light but allow visible light to pass, eliminating problems of solar interference.  Infrared also has greater potential throughput of up to 5 to 10 gigabits per second.  Overall, the challenges facing Li-Fi are no greater that the challenges facing RF.  The technology appears to be several years away from successful deployment in building automation.  But it’s coming.

 

Blog Articles

Most Recent

By Date

Tags

Clean Transportation, Electric Vehicles, Energy Storage, Policy & Regulation, Renewable Energy, Smart Energy Practice, Smart Energy Program, Smart Grid Practice, Smart Transportation Practice, Utility Innovations

By Author


{"userID":"","pageName":"Energy Efficient Buildings","path":"\/tag\/energy-efficient-buildings","date":"7\/23\/2014"}