End of Summer Update

This summer was a very good test of the changes I have made to reduce my energy usage.  Although it was hot, it wasn't quite as bad as last year.  The degree days show that it was well above average and slightly less than last year.    I did make a few changes in addition to the changes I made earlier in the year that were detailed here.

It is so humid here during the summer that it's very rare that we ever open the windows.  All of my windows are casement windows that have the bug screen on the inside.  So the first change was to remove all of the screens and store them away until early Fall when we start to open the windows again.  The reasoning behind this was all of the testing that's been done on solar air heaters using window screen as the absorber material.  If it's that good of an absorber, I need to just get it out of the way and let the shade reflect as much light and heat back out as it can.



The second change was to make better use of my programmable thermostats.  They have very specific schedules set to them now and in addition, the two guest rooms now have their dampers mostly closed on the days that no one is here using them.

The end result of this is some excellent news!  At least my wallet thinks so.   The total KWH usage for the months of June - Aug was down 4,255 kwh over last summer and the total bill for was down $365.  So far for the year I'm about 9,000 kwh under the usage of my six year average.



Water Heater Analysis - Part 3

Hopefully the saga with the water heater is coming to an end soon as the thermosyphon loop that was detailed here has been fixed.  After several months of sporadic discussions with my hvac contractor (who has supposedly been in contact with Water Furnace) about how to fix the problem, how much it was going to cost to fix, and whether I should bear the cost of fixing it, I now have an electronic valve installed on the outlet side of the desuperheater.  The valve only opens when the desuperheater comes on and should completely stop the thermosyphon loop that was sucking heat out of my tank.

 It's supposed to cool off a lot tomorrow and I turned on the hot water heater for the first time since the end of June yesterday.  When the desuperheaters stop supplying all of my hot water this weekend, I'll be able to get some temperature readings from the tank to see if this new valve really fixed the problem.

A Home Built Heat Pump / Energy Usage Monitor

A couple of years ago I bought a small robot kit for my kid to experiment with from a company called Parallax.  Along with the robot I bought a couple extra of their Stamp chips just to play around with.  After a couple of months the "this is interesting" factor wore off and I moved on to something else.  Last summer (2010) after working in the attic one day I wondered how hot it got up there and thought about the possibility of putting a temperature sensor in the attic that I could monitor remotely.   Already having a BS2P from Parallax on hand, I connected a Dallas Semiconductor DS18B20 to it and wrote a small program to log the data to my PC every 15 minutes.   After a few days, I started wondering how the outside temperature affected the attic temperature and added some more code to log the outside temperature as well (a year worth of data is here at BuildItSolar).  I then added an additional sensor in the crawl space and not knowing where I was going with it, put the project on the back burner.

The Birth Of My Home Monitor

In Dec 2010 I ran across BuildItSolar and Gary's Half Program and I soon knew where I was going with those few temperature sensors.  The project needed to grow.  A lot.  After looking at a couple of options for chips/circuit boards to monitor multiple 1-wire temperature sensors, I decided to just keep on using the Parallax BS2P's since I had them on hand.  Personally, I've not used the Arduino yet, but from what I've read I'm sure it would be more than capable of doing what I've implemented. 

What I'm Monitoring

I now have 16 temperature sensors installed around the house with most of them monitoring what my two Water Furnace ground source heat pumps are doing.  Here's a run down of where the sensor are located:

Upstairs	Logging Time
Attic	Every 15 minutes
Outside	Every 15 minutes
HP Supply Air	Every 1 min when HP On
HP Return Air	Every 1 min when HP On
HP Desuperheater Out	Every 1 min when HP On
HP Desuperheater In	Every 1 min when HP On
HP Earth Loop Out	Every 1 min when HP On
HP Earth Loop In	Every 1 min when HP On

Downstairs	Logging Time
Crawl Space	Every 15 minutes
Hot Water Tank	Every 1 minute
HP Supply Air	Every 1 min when HP On
HP Return Air	Every 1 min when HP On
HP Desuperheater Out	Every 1 min when HP On
HP Desuperheater In	Every 1 min when HP On
HP Earth Loop Out	Every 1 min when HP On
HP Earth Loop In	Every 1 min when HP On

I also have 7 sensors that detect when the different zones for each heat pump come on.  The upstairs heat pump has 3 zones and the downstairs heat pump has 4 zones.  Detecting when the heat pumps are on allows me to log the heat pump temperature sensors only when they have meaningful data.

When I received and installed my TED 5000 in Jan 2011 I quickly found out that the load profiling software didn't work quite as well as I wanted it to.  To fix that problem I added the ability to retrieve all of the "seconds" data from the TED 5000 and save it to disk and I wrote my own functions to do the load profiling.  Since I have all the data locally now, I generate all the usage graphs within my monitor program and rarely look at the TED web console anymore.

I now have a fairly complete energy picture of my house and can see not only how much electricity is being used and what's using it but can also see how well things are working.  It also gives me the ability to log some baseline data so that when I do make changes I can actually see if it makes a difference.

A Flatlined Hot Water Tank

One of the projects that I've been considering implementing for the house is a water based solar space heater similar to the $2K System that Gary over at BuildItSolar installed.  The basic idea is simple, gather heat from the sun during the day, store that heat in a large water tank, and distribute that heat into the house when needed. One of the issues that needs to be resolved before I jump in and start construction is what to do with all that heat during the summer.   From what I've seen on BuildItSolar and on the SimplySolar yahoo group is that most people use these system for both space heating and as a pre-heater for their hot water.  I would like to use all of the heat during the winter for space heating, but during the summer when I could make hot water, I wasn't sure that I needed it.  I suspected that my ground-source heat pumps with their desuperheaters provided all (or nearly all) of my hot water during the summer.  If that's the case, then my ROI would be significantly lower as the system would only be used during the heating season and would be stagnant for all of the cooling season.

Testing the desuperheaters

To find out if the desuperheaters could handle the entire DHW load I ran a couple of tests.  The first one was simple... turn off the hot water heater at the breaker.   After a short prayer service, the switch was flipped and the hot water heater flatlined at noon on May 24.

The graph above shows that the hot water heater really has been off for the last month.  The tank temperature seemed to be ok as all of the showers continued to be hot.  But to be sure, the second part of the test was to install a temperature sensor on the hot water tank.   The sensor is a DS18B20 and is installed against the inside tank wall underneath the insulation near the upper thermostat.  The sensor readings were spot on with the temperature of the water that I was drawing out of the tank, so now it's just a matter of logging the data every minute and graphing it.

The manual that came with the Water Furnace heat pumps says that the desuperheater circuity kicks out at 130F so I should never see tank temperatures above that.  The 5 day graph above shows that the tank temperature slowly drops during the early morning when the heat pumps run infrequently, but the temperature recovers nicely during the day and if it gets above 90 for any length of time during the day, there's a good chance that I will max out the tank temperature.  The big dip during the day on the 26th was a shower immediately followed by a bath just to see what would happen.

What I've found from this is that my desuperheaters can provide all of my hot water during the summer months as long as some thought is given to when things happen.  So, that brings me back to my original problem.  If I build a water based solar collector, what do I do with it during the summer months?

Hmm...

My Half Project: 4 Month Update

After 4 months I'm happy to say that I have not gotten bored with my Half Project, in fact I think I have become obsessed with it.   Most of the projects that I have worked on so far have been related to monitoring where I'm at with usage and making minor changes to see what affect they have on usage.

Some of the projects that I've worked on so far are:

1. Installation of a TED 5002-G Home Energy Monitor.  This has been a wonderful tool for allowing me to see what I'm using when I'm using it instead of finding out at the end of the month.  It also led to the discovery of a thermosyphon loop between the DHW heater and the downstairs heat pump that was causing the DHW heater to come on much more often than it should.
2. Purchase of a Kill-A-Watt meter.  This has been useful for determining what some of the individual loads in the house are.   Because of this, things like the printer are now on a power strip so that they can be turned off.   Like off, off... instead of the kinda somewhat off but not really off that the power button does.
3. Shades. Lots and lots of shades.   On all of the south facing windows that aren't shaded by the upstairs deck and most of the west facing windows.
4. A scan of the entire house with a Fluke thermal imaging camera.  This led to the discovery of some minor leaks around some doors and the attic entrance access panel.
5. A check of all the duct work and the repair of leaks that had occurred over time.
6. Some general conservation projects.  This turned out to have a huge impact on reducing my energy usage with little to no changes in my lifestyle.
7. A change in my driving.  I switched from using the SUV for everything, to only driving it when needed and driving the car for all my errands and trips into the city.

So what does this all mean?  It means that for the first 4 months of this year my energy usage for the house is down quite a bit from previous years and is the lowest it has ever been.

As you can see from the chart above, my usage is below or significantly below the monthly average for the first four months of the year. 

Which means that the total KWH usage for the year so far is well below previous years.  The degree days for this year have been slightly higher than for 2008 but yet I'm still 2000 KWH below the usage for 2008.

Now for the vehicles...  I thought that this would be a major area of reduction in GHG.  Switching my primary vehicle to one that gets 8 mpg more seemed like a sure fire win.  However, that victory has been hidden by two things.  First, a family members failing health has resulted in two 1,000 mile round trip visits to help out.  The whole family went which required taking the SUV.  Second, a change in scheduling now requires me to drive into the city three times a week instead of once a week at 80 miles per round trip. 



Even with all of the extra driving so far this year, I'm still equal on gasoline usage with my 8 year baseline.  

Conclusion:  The results so far have been extremely promising.  My goal was to reduce my usage by 5% per year knowing that some of the changes up front may result in drastic reductions in usage.  That drastic upfront reduction has occurred.  The minor conservation projects that I have undertaken so far will result in at least a 12% reduction in my energy usage and my electric bill for the year is down $379 (almost a $100/month) from last year.  Woot!

Conservation Projects

As part of my half project I have identified several areas where I could reduce my energy usage for little to no cost.

PCs:

I have three PC's in the house that are used infrequently (less than 2 hours per day) which used to be left on all the time.   The kill-a-watt meter showed that on average these systems used 150 watts of power.  All of the systems have now been set up to hibernate if inactive for 15 minutes. 

Energy Saving/Yr	3175 kwh
Initial Cost	$0
$'s Saved/Yr	$349
CO2 Reduction	3779 lbs

LIGHTS:

Most of the lights in the house have been converted over to CFL's.  However, there are three 75 watt incandescent floods that are in the main part of the house and are on 16 hours a day, every day.  These have recently been replaced with 8 watt LED floods.

Energy Saving/Yr	1174 kwh
Initial Cost	$66
$'s Saved/Yr	$129
CO2 Reduction	1397 lbs

Printer/Fax Thingy:

My HP PSC2510 which was detailed in a prior post has now been put on a power strip so that it really is off.  I may actually use the thing once a month.  It's pointless for it to be using power 24/7.

Energy Saving/Yr	149 kwh
Initial Cost	$3.50
$'s Saved/Yr	$16.40
CO2 Reduction	177 lbs

Phantom Loads:

A survey of the house with the kill-a-watt meter showed that several devices that are plugged in 24/7 are using power even when "off".  The TV sets in the two guest bedrooms, a CD player and treadmill in the exercise room, and the TV in the master bedroom that was swapped out for a new LG.  Individually these devices didn't use much power.  As a group, they do.

Energy Saving/Yr	203 kwh
Initial Cost	$0
$'s Saved/Yr	$22.35
CO2 Reduction	241 lbs

Water Heater:

The issues with the water heater which have been detailed here have been temporarily fixed while waiting on parts from the local hvac company I use.  The savings for not pumping heat into the garage should be noticeable.

Energy Saving/Yr	670 kwh
Initial Cost	$0
$'s Saved/Yr	$73.75
CO2 Reduction	797 lbs

Totals:

For the changes listed above, which had almost zero cost other than I just needed to be aware of what was going on, I expect to see the following savings per year.

Energy Saving/Yr	5373 kwh
Initial Cost	$69
$'s Saved/Yr	$591
CO2 Reduction	6,394 lbs

This is a significant amount just for being more aware of what I'm doing.  The energy savings of 5373 kwh is roughly 12% of my yearly consumption.

Ductwork sealing and insulation

Today was "review the ductwork" day and I'm happy to say that for the most part it was still in good shape.  When the system was installed, all of the joints were sealed with duct mastic and then insulated.

The only issues I found were where the ductwork joined the heatpump itself.   Tape is an evil thing when exposed to attic temperatures for many years as it starts to gets brittle and either loses it's grip or tears easily.  The only option is to take out what's bad and replace it.

Since my ductwork was already sealed and insulated I'm not going to get a huge savings from the work I did today.  On the other hand, it only took about an hour to check it all out and I used maybe $0.50 worth of aluminum duct tape that was left over from a roll used on the solar air heater.

There are several sources (here and here) that suggest that 10% - 30% of the conditioned air in a typical home is lost via leaks in ductwork.  It's an easy and cheap thing to fix...

LG 32" LCD TV

We recently replaced an old 21" TV set with an LG 32" LCD model #: 32LD350.  One of the nice things about this TV is the energy saving modes which basically just turn down the screen brightness.  When the Lakers are playing and the wife is trying to sleep, it's nice to not have a screen that's so bright it looks like the overhead lights are on.  I plugged the TV into a kill-a-watt meter to see what affect the different energy saving modes had:

Energy Saving Mode	Watts
Off	72.5
Minimum	74.2
Medium	53.0
Maximum	29.5
Screen Off	16.7
TV Off via remote	0

I have found that the maximum mode is fine even for morning viewing when the sun is lighting up the room and thus the TV stays in that mode. One thing I did find interesting is that the Minimum mode actually consumes more energy than having the energy saving mode turned off.

CNET did a review of a lot of other TVs.

Water Heater Analysis - Part 2

After some discussions with Gary over at BuildItSolar I've decided that the hot water heater was coming on much more often than it should for its warming cycles when the desuperheater was turned off for the winter.  Over the past month it has averaged coming on for 5-6 minutes about every 90 minutes.   This results in about 90 minutes of "on" time per day just to keep the tank warm.  The graph below shows the warming cycles of a typical day.

90 minutes a day @ 5500 watts = 8.25kwh per day = $.90/day.  Since I keep the desuperheater off from Nov-March, that's about $140 per year in tank warming cycles.  The question is why is it coming on so often.  Gary suggested that I might have a thermosyphon loop occurring and after some investigation I believe he is correct.  The downstairs heatpump sits right next to the water heater and the plumbing between the two units looks like this:

When the valve on the cold water line at the top of the water heater is open (as it has to be when the desuperheater is on), there is an instant flow of hot water out of the top of the water heater, down through the heat pump and back into the base of the water heater.  Shutting the valve stops the flow and the lines stay cool.  Even though all the piping is insulated, shutting the valve had an immediate affect on the number of tank warming cycles that occur during the day as shown below.

The tank now cycles on for 7 minutes every 6 hours.  The "on" time for warming cycles has been reduced from 90 minutes to 30 minutes a day.  For my 5500 watt water heater, that's 825 kwh per winter that I'm not using and 982 pounds of CO2 that's not being pumped into the air.  In addition I'm also saving $.60 per day or $90 a year.

Osprey

The osprey are busy getting their nest ready for this year.  They arrived a couple of weeks ago and got right to work fixing what little damage occured during the winter.   This is nest #2 and sits on a "no wake" sign that's about 150 feet out in the river.   Nest #1 is made from a storm destroyed duck blind that I put a surface on for the osprey to build a nest.  It's about 500 ft out on the bay side of the property.