The Bill Comes Due

You know the feeling don't you?  You open up, say, the credit card bill at month's end and you think, all those little numbers cannot possibly add up to that BIG number at the bottom of the bill.  Unfortunately, all those little numbers do add up.  And so it is true with my solar hot water project.

Jumping to the bottom, the number is $12,000, give or take a little depending on what you include.  And, yes, that is a lot.  But I was not trying to do a budget job, and mistakes along the way cost mucho dinaro.  Still, assuming the federal government pays for 30% that leaves only $8400 for me to make up with oil savings and still seems possible within a few years.  More feedback on that later.

There are a handful of big ticket items and about one hundred smaller purchases.  To begin, let's talk about the larger items or main components which total $6353.12.

System Vendor Date Description Price 1 Solar Panels EcoDirect.com 08/04/11 Solar Panels $2,829.85 2 Tank Houseneeds 09/25/11 Hot water tank $1,825.08 3 Hydronics Houseneeds 08/09/11 Pump Station, fittings $557.83 4 Hydronics Portland Group 04/12/11 NA26711 Caleffi pump $363.63 5 Controller House Needs 03/29/11 iSolar Plus Controller $333.75 6 Hydronics SunVolt Energy 11/03/11 Ecocirc Pump $189.25 7 Solar PV Amazon 10/10/11 two 20 W Solar Panels $156.48 8 Hydronics Houseneeds 08/25/11 Fittings for pump station $97.25 The largest most expensive purchase, by far, is the panels at about $3000.  The good news is that EcoDirect has very reasonable shipping at $130.  The same shipping from AltE would have been over $1000.  It is also worth noting that the price would have been a lot lower if I could have used two 4×10' panels rather than three 4×6'. The second most expensive item is the solar hot water tank.  At about $1800, the price might be more than a little surprising to anyone that has purchased an electric hot water tank for, say, $400.  But there are two things to keep in mind.  First, this tank has a heat exchanger inside so I didn't need to configure an external heat exchanger and a second pump.  Second, this is a stainless steel tank that should last more than twice as long as a standard steel tank.  At least that is what I am hoping and the lifetime warranty makes me believe. Items 3,4,5, and 8 basically make up all of the Califfi Solar Pump station including the pump, controller and fittings.  This is a whopping $1,352 which seems like an awful lot for what it does.  The Caleffi equipment is nice, but it seems grossly overpriced.  Caleffi does nicely put all the little plumbing components (check valve, pump, temperature gauges, pressure gauge, air bleeder, fill ports, controller) all into one nice little package.  But the price will make the budget conscious person think about making there own system instead of buying from Caleffi. Item 6 is me having to buy the pump a second time because the Caleffi pump really isn't the right one for the job.  I have listed the old pump on ebay and Amazon and hope to recover some of the money Item 7 is the solar panels, which were also purchased twice for this job.  First I bought two 10 watt panels and then discovered that they were too small, then I bought two 20 watt panels.  Also, my insistence on using solar electric power contributed greatly to the cost of this system.  In addition to the cost of the PV panels, the pump is more expensive and the controls and electronics are more complex.   It is no wonder that AC power is used for most of these systems. All-in-All, these main components represent only 50% of the total system cost.  The "balance of system" or other parts cost just is much which is shocking.  I will cover those costs in a separate post.

Laing Eco-circ pump

   It was probably too much to expect everything to work perfectly and it hasn't.

   When the Laing Eco-circ pump turns, it is designed to use as much electric power as possible from the solar panels (PV).  Unfortunately that causes the system voltage level to drop to 17 volts and the battery charge controller stops working and eventually the controller would shut down due to lack of power.  A secondary problem is that the pump is circulating the water too fast.  It is pumping well in excess of 5 gpm (gallon per minute) which is much faster that the 2.5 gpm that is recommended by Heliodyne for the solar panels.  Too much gpm and using too much electricity.

    So I contacted Laing technical support (which appears to be Xylem Inc part of ITT) and got some great help from Amy Flores.  Long story short, it looks like Caleffi made a mistake by using the D5 "strong" pump.  That pump is really intended more for maximizing flow of fluid which is not what you want in solar hot water panels.  It is probably great for well water pumping, but not for solar hot water panels where flow control is needed.

   Fortunately Laing makes an Eco-circ D5 "Vario" pump which has, as the name suggests, variable flow settings.  There is a dial on the side of the pump where you can adjust the volumetric flow.  The image shows the two different pump types.  On the left is the "strong" pump that pumps the water as fast as possible.  The pump on the right is the "vario" version with a small red dial that allows the flow to be adjusted and save some electric power as well.

 The design of the eco-circ is really excellent.  The pump/impeller side can be easily separated from the involute/pipe fitting side.  This allowed me (really Amy gets credit for this idea) take the new motor and attach it to the Caleffi fittings (which are custom).  So I took half of one eco-circ and screwed it to the other half of a second eco-circ pump to get what I needed.  The "vario" pump was purchased from Sun Volt Energy (www.sunvoltenergy.net) for $179 which is an excellent price considering I paid $325 for the Caleffi pump.  Sun Volt got the pump out to me in just a couple of days which was great.  The image shows the two halves of the pump.

 As can be seen in the picture, the official part number for the "Vario" is D-38/710B.  I found the Eco-circ part numbers to be confusing.

  The Results:  This is the best part.  Using the dial, I could adjust the speed of the motor until I had 2.5 gpm flow as shown in the picture.  I give Caleffi credit for including this nice flowmeter into their pumping station design.  Without the flowmeter, I would have no idea what kind of flow I was getting.

   Now for the best part, connecting the pump to a power supply and the power supply to a Kill-a-watt, I found that the power used is only 9 watts versus the 50 watts used by the old eco-circ pump.  Can't wait to see if it works as well on sun-light power.  Think about it for a minute. 2.5 gpm for 9 watts!  Many home circulators require more than ten times the power to do the same job.  Well done Laing.

   The hot water tank still needs to be connected to the domestic hot water system.  Hope to do that soon.  A plumber is coming tomorrow to look at the system and another plumber said he would do it for $1100.  I would prefer to do this myself, but officially, only a licensed plumber is supposed to do the job.  The whole project has turned out to be way too expensive.  However, I must complete the project at this point to be done with it and get the benefits.