Posts Tagged ‘GFX’

Solar hot water in New York

May 12, 2010

Here’s a solar hot water (solar thermal) that GreenHomes recently installed.  On a chilly and cloudy day in upstate New York, it’s sitting inconspicously on the roof, cranking out the hot water for the homeowners.  With a 30% federal tax credit, these make sense in overcast New York.  And Washington state.  And in sunny California and sunnier Colorado.  Solar hot water is a great way to take a big bite out of the 15% of our total energy bills that we pay to heat water.  (And heat water that we generally let run down the drain–but drainwater heat recovery is another issue.)

A Green Bathroom–Energy and Water Efficient

November 7, 2009

OK, so you what to make your home more efficient, but you need bathroom makeover–or a new bathroom altogether–and you need it now.  There are still things you can do that will have an immediate impact and improve your home’s overall performance and energy-efficiency.  Here’s a real example from a project being wrapped up right now.

dense packing cellulose insulationWe’d like you to start by taking a look at the whole home’s performance.  At a minimum, you’ll want to look for thermal deficiences–air leaks and poor insulation around the bathroom iteself (and we always want to look at combustion safety before and after!).  Key spots include areas behind tubs and shower enclosures–often ignored and left wide open when building a home.  Of course, you want to make sure you have adequate insulation in the walls–in this case the walls were completely empty and needed to be dense packed with cellulose.  Replacing the tub also allowed easy access to make just the critical air-sealing was done.

One of the early parts of a project is making sure the plumbing in in order.  This particular project required new supply and drain lines–and this opened up a few big opportunities.  First, the water heater (actually an indirect storage tank fed by a 96% efficient sealed combustion boiler) was moved directly under the bathroom, about 40 feet closer to the bathroom.  This is a big deal from both an energy and a water efficiency perspecitive.  The closer your hot water is to the bathroom, the less time you wait for hot water for your shower, the less water that goes down the drain, and the less heat lost as water left in the pipes after you’re done cools down.  

GFXOn a related point–and one that’s likely to require some wrestling with the plumbing inspector–you can use smaller diameter pipes (IF you’re using low-flow faucets and shower heads so you still get sufficient supply–this is a big deal, but too complicated to go into hear.  (Google “structured plumbling”.)

The other opportunity on the drain side is “drainwater heat recovery“, using a device which lets you capture heat going down your drain and using it to preheat incoming cold water–saving the amount of heat you need to dump into the incoming water and saving you energy and money.  This is hard to do in a one-story house with no basement or crawlspaces, but makes sense for a lot of homeowners.  The less water you need to heat, the less energy you use.

EPA has kicked off a “WaterSense” program to help identify water efficient products and practices.

efficient toilet

There are many choices.  This particular toilet by Toto uses 1.28 gallons per flush, and it works!  Unlike the low-volume toilets of several years ago, the better ones have been designed specifically to work at lower volumes.  And they do.

shower headNew shower heads also use a lot less–and still deliver a comfortable shower.  In this case, the 1.6 gallon per minute shower head hasn’t arrived yet, but the one in place uses a reasonable 2.5 gallons per minute.  Again, less water over all, and the less hot water you use, the less you pay to heat it.  The are a variety of shower heads that will take you even lower–with good results.  Personal preferences come into play here, but most people should be able to find a 1.6 gpm low-flow fixture that works for them.  And many are happy with some even lower flow heads.

You didn’t expect me to leave this topic without talking about electricity, and I won’t!  Using efficient bathroom lighting can chip away at the electic bill.  CFLs have come a long way, and can provide excellent quality light.  Dedicated CFL fixtures are available in a wide variety of styles ranging from basic to high-end designs.  In this example, the sconces on either side of the mirror have a bright, instant-on lamp, in a warm color that avoids the sterile flourescent look that some find ghastly.  As you can see in the inset picture below, the fixture is a dedicated CFL fixture, and only accepts CFL lamps, no screw ins.  LED technology is evolving, it not ready for prime time in lamps intended to send light in all directions, and it wouldn’t yet be a good fit for these scones.

CFL sconce in green bathroom remodel

While LED lamps aren’t ready for sconce applications, they excel in recessed can fixtures.  I’ve written on the CREE and HALO recessed can LEDs before.  Both are great choices today.  In the case, the HALO fixtures were used because they come with a trim kit rated for wet locations.

HALO LED lighting and Panasonic Bath FanYou’ll also notice in the picture an ENERGY STAR labeled Panasonic bath fan.  It’s quiet and efficient and really gets the job done.  In this particular project, it will eventually be replaced by a heat recovery ventilator, but it along with the Renewaire bath fan are excellent fan choices.

As an aside, I often make light fun of bamboo as a green choice.  This isn’t really a condemnation of bamboo or any other sustainable material.  My beef is that people focus on materials before they consider they overall performance of a home–comfort, safety, durability (what good is it if you let greener materials rot in a poorly designed home?), and energy-efficiency.  Having said that, when you’ve got the performance issues ironed out, it’s great to look at materials, too.  And in the picture above, I really like the bamboo used on the ceiling.  There, I said it! 

Of course, at the end of this project, having added ventilation fans and done insulation and air-sealing, we need to again check equipment for combustion safety, and check pipes for gas leaks!  The combustion safety is a bit easier since the project included switching over to a sealed combustion boiler.  But this is an important step not to be ignored.

Even in a bathroom remodel, you can apply home performance concepts and wind up with results that make you happier–less waiting for hot water–and not running out of hot water! and eliminating drafts, condensation, and moisture and mildew problems.  And you save energy, to boot.  Good stuff!

Thanks,
Mike

GFX — Drainwater Heat Recovery

September 11, 2009
According to the U.S. Department of Energy, as much as 250 billion kWh worth of hot water is sent down the drain.  We pay to heat water, and then we pour it down the drain.  That’s not good.  Fortunately, a good percentage of the wasted energy is recoverable.  
GFX installed in the drain of a home pre-heated incoming cold water and lowers the energy needed to provide hot water for your home.

GFX installed in the drain of a home pre-heated incoming cold water and lowers the energy needed to provide hot water for your home.

 
Several manufactures make version of drain water heat recovery systems—and one class in particular seems best suited.  These are gravity film heat exchangers, or GFX.  Water flowing down a drain pipe tends to cling in thin a film to the sides (not fall down the middle as you might imagine.  We can take advantage this to “grab” the heat from the waste water and add it to incoming water.  The two streams are separated by two walls of copper, so your incoming water is not fouled by the outgoing water.  In the photo, you see an actual installation (from my basement!) of the GFX, with the cold water inlet in the blue box, and the preheated water outlet in the yellow box.

The savings you’ll see depend a lot on whether you use batches of water (like baths, dishwashers, clothes washers) or whether the water drains as you’re using it, as is the case with showers (these simultaneous uses deliver the best recovery).  Depending on how you use water, you could save between 20-40% on hot water costs with a GFX, all from a piece of equipment with no moving parts, that uses no electricity, and that should last 50 years.

The GFX system can be a good complement to high-efficiency water heaters and solar hot water systems.  There are some installations challenges in existing homes, and especially in home built “slab on grade”.   There are also a variety of installation considerations to optimize performance.  But for many homeowners–especially those who have teenagers with a proclivity for hour-long showers!–GFX can be an attractive option.

Thanks,
Mike

The Water/Energy Connection

August 3, 2009

Green home or regular home, water efficiency and energy efficiency are tied to each other in many ways, started at the source.  It takes energy to pump and move water.  It takes water to make electricity (in the case of cooling towers, for example).  And many significant energy users in the home are tied to water use.

For example, inefficient clothes washers, dishwashers, and high flow shower heads all use a lot of hot water.  The more hot water, the more energy used to make  the hot water.   Moving to more efficient water-using appliances can save you twice.  In some places like Atlanta, Phoenix, and much of California, the water itself is a big issue.  California is moving in the direction of water rationing with graduated tariffs based on volume usage—and high use can mean expensive water bills.

As I just alluded to, it doesn’t stop there.  Water heating can be one of the largest uses of energy in a home.  And needlessly throwing hundreds of gallons of water you just paid to heat down the drain just doesn’t make a lot of sense.

So what can you do?  I’ll start at the high level, and we can pursue this thread further in the coming weeks and months.  But here’s a quick and dirty version: 

  1. Fix leaks!  Dripping faucets can leaks dozens of gallons a day. 
  2. Install new water saving fixtures and appliances.  New designs really work.  ENERGY STAR can point you to clothes washers and dishwashers.   (I do like our Bosch Nexxt Washer.)  And the new WaterSense program at EPA can give you direction on fixtures.
  3. Smart plumbing—hot water that has to travel hundreds of feet to get to your sink or shower means a lot of water that you once heated but that got cold while it sat in the pipes goes down the drain, wasting the water and the energy you’d used to heat it.  Shorten the distance!  With new water heating and plumbing technology, this is possible.
  4. Speaking of those pipes, insulate them!
  5. Look into drain water heat recovery.  (I’ll post pictures when I install one in a few weeks.)
  6. Look into solar hot water.  This technology is vastly different from the not-always-ready-for prime time systems of the 70s and 80s.
  7. No water heating involved, but move toward less water intensive landscaping.

 It’s possible to save water and save energy and money at the same time!

 Thanks,
Mike


%d bloggers like this: