LED Lighting Update

IKEA has finally put its purchasing power and design talent toward LED lighting.

I think they hit it out of the park, and did it a year ahead of Home Depot.   In the catalog, they mention that the bulbs never need replacing.   Nice.

http://www.ikea.com/us/en/catalog/categories/departments/living_room/20515/

Solar Thermal for the Masses

For a few years now, I've independently been trying to solve the problem of solar domestic hot water (SDHW) systems that are too expensive.  Here's what I've come up with: a simple and cheap solar hot water system design that at the very least should give manufacturers food for thought.

The Problem:  Even small SDHW systems cost way too much ($6-$8k on average)
Since gas heated water is still very cheap, the average family can only save $30/month with solar.

My Opinion:  The US SDHW industry is in deep trouble now, and will remain so until $2000 systems are available. 

A Solution?:  Bring back Recirculation for Freeze Protection (RFP) in all but the coldest climates in the US.

History:  RFP is still used in many non-freezing climates, so it's still a free option on most solar thermal controllers. It's reliability took a hit in the 80s when many systems froze because power failures often accompanied freezing weather. (Freezing rain will often take down power lines) Because of this, most installers eschewed this method for most climates. Historically, it can't be used with flat plate collectors because in the winter it takes too much energy to prevent the collectors from freezing. (They are pointed at the night sky which is usually colder than -100F on a clear night)

Why This Solution Can Work: A. If Evacuated Tube (ET) collectors are used, the heat required for freeze protection is almost negligible, and B. In case of a power failure, the system will self-freeze-protect by thermosiphoning. C. The outdoor piping is freeze and stagnation tolerant hose.

Yes, the ET collector header can still freeze and break, but the probability will prove to be too low to worry about. (Drainback systems have a few failure modes including freezing, but we still use them because the Mean Time Between Failures (MTBF) is long enough.)

I've tested this system for two winters now, and it works great in Denver. Here's a link to the YouTube tutorial about the system.  http://www.youtube.com/watch?feature=player_detailpage&v=N5hdu9p75Vg

For more info and pricing, here's a link to my presentation at the 2012 ACEEE Hot Water Forum.

100% Off-the-Shelf:  Only  five of the items required must be purchased somewhere besides Home Depot:

1.   The pump:  http://www.sun-pump.com

2.   The Pump Controller:  http://www.sun-pump.com

3.   The Collector:  http://www.solarheatexchangemanufacturing.com/NewFiles/heatpipe.html

4.   The ECV, which is a low power consumption electric ball valve from Taco

5.   A 110V SPDT relay is also needed to control the ECV just right.

Just Say No to Twitter

It's an annoying fad that is a complete waste of time for the average person.   And time is your most important dwindling resource.  So cut it out.

Plumbing Efficiency in New Construction: Using a Little Pipe to Save a Lot of Water and Energy

All of us have had the annoyance of waiting for hot water.   Whether it's to do a good job of hand washing or to get the morning shower over quickly, you know the feeling.

The conventional wisdom has always been to install a recirculation pump.   The best one available is probably from ACT:  http://www.gothotwater.com/hot-water-systems/how-it-works
It's a good solution, I guess the only problem is the cost, which is about $200 plus labor.

However if you pipe your hot water directly to each fixture with 3/8" pex, you have solved the problem.  But now you have to convince your plumber.

Gary Klein has developed a plumbing strategy that eliminates the need for a recirculation pump if the house you're designing isn't too damn big.  The strategy is called Structured Plumbing.  The reason it works is that there is very little water in the hot lines going to each fixture.  It's similar to "home run" piping.

Michael Chandler at Green Building Advisor has sketched for us what it means.   (Michael is uniquely qualified for that since he is a master plumber who designs and builds green custom homes)

Somewhat non-intuitively, it requires more pipe, which would be expensive with copper, but with PEX it's very easy and cheap.  PEX is very easy to work with,  especially in the 1/2" and 3/8" sizes, and is color coded.   Since it bends easily, you rarely need an elbow.   So you wind up using less fittings and more pipe.  That's OK, since the pipe is very cheap and should last 100 years.   In a small house, this extra cost is less than the $200 for the ACT pump, and it shouldn't need replacing during the life of the house.  Home Depot now sells the manifolds that make it even easier.

So thanks to Gary and Michael for giving us what will become the new standard method in residential plumbing.   If you're a builder, just hand this sketch to your plumber.  He may be a little reluctant at first, but if he's used to PEX he'll understand it quickly.   If he's not used to PEX, get a new plumber NOW.

Do you still need to insulate all the hot water pipe? Yes.   With insulation, the second person in the shower has instant hot water if there is less than 30 minutes between showers.

iCast Providing Much Needed Help to the Multifamily Industry

iCast has begun providing a win-win for apartments.   Most multifamily buildings are good candidates for money-saving energy efficiency measures.   Unfortunately, building owners often don't have a good way to find out the most cost effective upgrades, nor the money to implement them.

Here's a press release about the iCast program:

"iCAST, a Colorado based not-for-profit was recently awarded a 30 month cooperative agreement with HUD to establish an innovative program that provides new ways of making cost-effective investments in Energy Efficiency (EE) for the low-income multifamily housing community. iCAST is tasked with providing a simple, yet comprehensive program that achieves cost savings for owner/managers while creating a more comfortable and healthier environment for residents via an integrated suite of improvements, including energy conservation measures, behavior change measures, demand side management measures that reduce peak/demand charges, water conservation, indoor air quality, etc. The HUD award also offers a unique combination of incentives, rebates, and financing programs to owners and managers. iCAST designs solutions so that your investment pays for itself. You start saving money from Day 1! iCAST projects have reduced the energy bills of over 1,000 multifamily units by an average of 30%, while helping owner/managers hedge against rising energy costs, improve the value of their properties, and enhance the quality of life for residents."


Please note "behavior change measures".   That is an interesting topic unto itself.   Here's an example:
When you have "free heat" in your apartment, you might abuse it without even knowing it.   You might keep your thermostat at 74F all the time, and open a bedroom window for "fresh air".  Behavior like this can easily double the amount of heat that you use, causing your "affordable apartment" to be less affordable for the building owner.
"Behavior change", in this case, is training the residents to keep the windows closed in the winter to save energy.


Another example might be to train tenants to program and use a setback thermostat.  Many  tenants (usually the younger ones) are highly concerned about the environment will use them if given the chance.

Multifamily Energy Savings: The Conflict of Interest

There are thousands of multifamily buildings in the Denver area that need some energy efficiency improvements.   The most cost effective of these improvements are usually simple control upgrades.

One example of the "lowest hanging fruit of energy efficiency":

Steam boiler systems cannot be zoned with individual 24V thermostats in each apartment.   Therefore, one thermostat controls the whole building, and the location of that thermostat is critical.  In a 20 unit building on 19th Avenue, I found it in the main hallway.   Unfortunately, the main doors were always cracked open a little, and so the hallway was always cold.   Over the years the heat emitters (radiators) had been removed from the hallways.

Therefore, that thermostat location caused the boiler to be on all the time, and all the tenants were roasting and opening their windows all winter to shed enough heat to be comfortable.   This is known as the "double hung thermostat method".

So, for $600, I purchased a steam-compatible thermostat and installed it in a more appropriate location.  The savings are more than $3000/year and will increase as the cost of gas increases.

The average energy auditor doesn't know this stuff.

It can only be learned through field experience as a heating technician, but books from HeatingHelp.com can get you half the way there.   They can be read and understood by almost anyone.

A typical building owner might have a building that seems to have a higher utility bill than his other similar buildings, but since he doesn't know heating controls, he is forced to call a contractor.  Here's the inherent conflict of interest.  Even if the owner tells the contractor "please try to reduce the gas usage of this boiler" the contractor is loath to do anything that might cause a comfort problem and a callback.   The contractor  isn't responsible for the heat bill, but if he touches or upgrades the control system, he is suddenly responsible for having enough heat for every apartment.  So that contractor is more likely to make every apartment 74F instead of the 68F that the owner would prefer.

A Quick Look at the Near Future of Renewable Energy

 Solar Thermal may be dead: http: //www.greenbuildingadvisor.com/blogs/dept/musings/solar-thermal-dead

But PV will reach grid parity soon: http://climatecrocks.com/2012/05/30/solar-grid-parity-inevitable-wholl-be-the-leader-in-this-disruptive-technology/

Even though right now it's in the midst of a "correction": http://www.greenworldinvestor.com/2012/05/31/6-reasons-why-the-time-for-buying-solar-stocks-has-arrived/

Cheap gas is delaying renewable uptake, but using gas for making electricity inherently has a VERY low overall system efficiency, and seems a waste of a non-renewable energy source.

Conclusion: Inevitable but rocky growth for PV, with a Darwinian edge.


By the way, Jay Burch et. al. at NREL are trying to save solar thermal by finding a technology that provides a "disruptive cost reduction". Here's an abstract of a forthcoming report:

"Executive Summary

The objectives of this report are to:


(1) Identify the target market for solar hot water heaters that will provide the largest U.S. energy savings potential relative to other advanced hot water heating technologies, and, (2) Identify potential technology pathways and cost/performance targets that must be met to enable solar hot water heating systems to achieve large energy savings.  The market environment for solar water heating technology has changed substantially with the successful introduction of heat pump water heaters (HPWHs). The addition of this energy-efficient technology to the market increases direct competition with solar water heaters (SWHs) for available energy savings. It is therefore essential to understand which segment of the market is best suited for HPWHs and focus the development of innovative, low-cost SWHs in the market segment where the largest opportunities exist."