Solar Southwest Florida

Fafco Solar Video on Pentair Variable Speed Pump

Fafco Solar just released a short promotional video on the Pentair Variable Speed pool pump.

The variable speed pump is a perfect match for solar pool heating systems, especially when an automatic controller is used. Without a controller the pump can be scheduled to run at optimum solar circulation speed when solar energy is most likely to be available. Adding a controller adds the capability of changing the pump speed based on the availability and demand for solar heating.

With or without solar energy, the variable speed pump will pay for itself with energy savings. You can cut pumping costs up to 90% with this great technology while getting a far quieter and longer lasting pool pump.

SunPower is just getting ready to ship the first E20 series panels to dealers in about a week. There is a lot of hype around the most efficient and best performing solar module in the industry for residential and commercial applications. The new E20 Series modules are currently rated at 327W and boast a 20.1% efficiency, an improvement from the 19& efficient E19 series.

My first 3D computer model just came out with the new SunPower modules. They look great!

SunPower E20 327W Photovoltaic Module 3D Drawing

Today I had an FPL representative at my home to test my duct work. I was really just expecting them to pressurize my ducts and place some little blue stickies next to all the leaks found in the attic. I was quite wrong, and very pleased with what actually transpired.

The specialist that arrived (on time) was very professional. She set up the equipment to create negative pressure in the whole house and asked me what I knew about the duct system and the home. She took pressure drop readings at every register and return in the home. I volunteered to walk around and write the readings down since I was interested in the process.

She explained in detail what high and low readings meant, and what levels indicate a problem. We identified about 6 registers that presented worrisome readings where there may be duct leaks. I thought that was the end of the evaluation. Again, I was wrong.

She got up in the attic and carefully inspected and identified all of the places where duct leaks were occurring, prioritizing the search based on the readings taken earlier. Then she put her equipment away and brought out her laptop. She made a detailed drawing of my ducts and registers, and identified locations of each leak. She printed out the results on her portable printer along with rebate certificates and a list of FPL authorized A/C companies that accept the program certificates.

What really impressed me was her prior knowledge of my home. She came prepared with my monthly energy use and knew quite a bit about my bill. We discussed my variable speed pool pump and the FPL On-Call load management program. She made recommendations about the duct repairs and generally about energy efficiency. She took her time and ensured that I was satisfied with the work.

Overall, she was at my home for almost three hours (I have two air handlers). It was a very thorough inspection, and I am sure I will save money in the long term as a result of the evaluation. I received the maximum $154 in certificates to go toward duct repairs.

The cost of the evaluation is $30 for the first A/C and $15 for each additional. More information is available  here: http://www.fpl.com/residential/energy_saving/programs/ac_duct.shtml

Solar pool heaters work better with variable speed pumps because the optimum flow rate can be achieved to maximize solar performance. A single speed pump is typically fine to use with solar pool heating, but if you want maximum pool heating, a variable speed pump can both save you a tremendous amount of money and provide the proper flow rate.

Typical efficiency vs. flow curve for solar pool heating panels (FAFCO Sunsaver shown).

Most solar pool heating panel manufacturers recommend a flow rate of 4 gallons per minute per panel. If you have seven panels, you need a flow rate of 28 gallons per minute. Anything less and the efficiency drops off quite rapidly. Anything more and you are wasting money on  your pumping costs, pumping water at a rate higher than required for solar pool heating to be efficient.

When we have a solar pool heater installed, we insist that every job gets a flow meter installed (at least temporarily).  The pump can be programmed to operate at the proper speed when solar pool heating is likely to be required. With an automatic controller, the pump can be set to go to optimum speed whenever solar pool heating is required, but reduce the speed when heating is not active.

There are lots of other variable speed pump resources on my Solar Southwest Florida blog. I have also assembled some Pentair variable speed pump marketing videos below. Enjoy!

I recently set up a Wattvision meter on my Fort Myers, FL home to evaluate its effectiveness. I have to say, I love it! It definitely clues you in to how much energy you are using, when you are using it, and what appliances cost to operate. The device pays for itself by identifying power hogs. For example, I cut down the time my pool lights come on each night because they were consuming 600 watts! On the other hand, I decided to run my fountain longer each day because it uses next to no energy.

The charts on the Wattvision website are excellent. You can view real time, hourly, daily, and monthly data, and can download raw data to use in spreadsheets for further analysis. Take a look at this chart from last Monday.

What can you learn from the chart? Here is my analysis of what happened on Monday (list numbers correspond to numbers on the chart):

1. The baseline load for my home is around 400W at night when we are sleeping. This energy goes to digital video recorders, chargers, TVs, coffee maker, and other appliances that draw a small amount of energy constantly, plus some outdoor landscape and security lighting. The little bumps show the times when the refrigerator is running.
2. The water heater starts up about 4-5 times a day just to keep the water in the tank hot. Around 6:00 am we got up, took showers, and got ready for work. We used a substantial amount of hot water, and the water heater ran for a long period of time, costing us about 50 cents per hour of operation. Around dinner time the water heater worked during cooking and dish washing, and came back on as we got ready for bed.
3. My variable speed pool pump is scheduled to run at low speed from 9:00 am to noon, and again from 2:30 pm to 5:30 pm.
4. The pool pump ramps up speed from noon to 2:30 pm to give the automatic cleaner time to work and get adequate pool filtration.
5. The baseline during the evening increases as we use lights, watch TV, and use computers. The fountain and outdoor lighting also comes on at dusk.

It’s a common misconception that one solar panel can do it all. While technically it is possible for solar electric panels to create electricity and to heat water using electricity, this is terribly inefficient. Any time energy changes forms, there is an efficiency loss, and in the case of heating water with electricity, the losses are tremendous. That’s why we have solar photovoltaic modules for electricity and solar thermal modules for heating water.

Solar photovoltaic modules produce electricity and are approximately 15% efficient using today’s technology. That means for the amount of surface area they consume on your roof, only 15% of the sun’s energy can be converted to electricity. While that may sound low, it is effective at creating energy for powering appliances in your home that have no solar thermal or other solar alternative.

Solar thermal modules that heat water do not create electricity. They take the energy of the sun and transfer it directly to water running inside the panels. This is a simple process. Anyone who has left a garden hose coiled up in the sun realizes how hot water can become in a rubber hose. This same concept, along with purposeful design and material technology, is used to make solar pool heating panels. Because electricity is not involved, the efficiency of solar pool heating panels is fantastic – around 5 times that of solar photovoltaic modules. Of course, solar thermal panels can’t do some things, like charge your iPod or run your television.

Both technologies have their place and their purpose. What is key is understanding your energy use and determining a cost effective and purposeful plan to reduce your dependence on utility electricity while maintaining or increasing your standard of living. Your solar dealer can point you in the right direction!