Yipee, we just had a drainback solar hot water system installed! We bought this home in October 2007 and have loved it except that the hot water system has been tankless so the oil-fired boiler (100% VWO) turned on every time we needed hot water. The system consists of 3 4x8 collectors, a 120 gal. tank and a drainback tank and the tank is at 148 F at 10 pm tonight.
excellent! i miss solar hot water, but that's the joy of apartment living. you'll enjoy that for many years to come.
I'm thinking about something similar. Would you care to divulge an approximate cost for your system? And in RI too. That bodes well for sunny Colorado. I've heard that solar thermal can actually do pretty well in less than full sun. Can anyone comment?
nice system. I would like to know the cost too. mainly.. where to get the panels and flow rate.. or other pump specs.
$7k but this cost comes down when considering a RI State Rebate of $1750 and a Federal Tax Credit of $2k for a final cost of $3.25k. I'd like to think that it will also boost our home value but that remains to be seen. The types of collectors, number of collectors, tank size and technology selection will all depend on location and cost. It does warm up even on rainy days although the evacuated tubes are reported to work better under these conditions than the flat plate collectors that we used. We used flat plate due to lower cost and that we had the room for larger plate collectors on our roof. Our system was sized to provide 100% hot water for spring through early fall and 80% in the winter. This is also the reason for the larger tank. It remains to be seen how accurate this will be for the winter but the collectors are placed at a 55 degree tilt to maximize the winter sunlight profiles. Our system features a drainback system which consists primarily of a water tank, a smaller tank ("drainback tank") that stores heat-transfer fluid, a solar panel array that collects heat from the Sun, and a heat transfer system that transfers heat to the water tank. The heat-transfer fluid only circulates through the system when the panels are collecting a usable amount of heat from the sun's rays. The alternative was a closed loop system which I didn't care for as it includes the burying of a coiled loop in the ground to dissipate extra heat. Just seemed to me that it isn't always wise to introduce heat into the ground if not needed (I've had friends who have had their geothermal pipes dug up 3 times because of leaks in less than 5 years!). The output from our tank now passes through our boiler so that if the temperature is less than 120 F (?), the boiler will boost it up. This will not be much of a problem in the winter as the boiler is running anyway. However in the summer I've turned the boiler off as it also warms the house whenever it is on. Although the boiler is in the basement, when it is on it does warm its environment and this heat will invariably rise into our home. The only slight negative about our system is that I would have preferred a DC pump that is PV-powered. However the installer recommended against this as the pump for the drainback system needed more lift than most current DC pumps. Interestingly the current issue of Home Power magazine shows a PV-powered pump so I still might change this over in the future. Our system was purchased and installed by Island Solar in Jamestown, RI. He is a small business and does sell components as well as full systems. Initially I thought of installing it myself but now after seeing his efforts I am VERY glad that I didn't! It was much more work than I had realized and our installation was fairly easy as we have a single story home.
It does OK even on cloudy days, too. Our controller heats our 80-gallon tank to 150 degrees, which gives us about three days of hot-water use for our family of three (including a teen). Two 4'x8' panels heats up way more than we need for normal sunny days. One rainy spring/winter was 40 consecutive days of clouds & rain. The array limped along between 110-120 degrees and we only used electricity three times for a few hours each. Thermal mass. A 120-gallon tank can probably handle up to a week of cloudy weather, especially if the tank is well-insulated. Makes it a lot easier to fill the whirlpool tub, too. Our 50-gallon heater just wasn't hacking it unless we filled the tub with more warm bodies... Home Power rocks. That gave us the confidence to do our system. We used panels that are at least 25 years old and still going strong, so the systems will last long enough that you'll get heartily tired of removing & reinstalling them with each roof replacement. I've heard that the DC pumps still have brush problems. There's also the issue of natural circulation reversing the flow at night and cooling off the tank too much, but that's a design problem that can usually be avoided. If I was doing our tank over again I'd put the hot-water return at the very bottom instead of saving a few feet of copper by putting it straight in the top.
I'd expect Nords performance to be considerably higher than mine as he is in Hawaii and I'm in Rhode Island. The costs should be significantly less as well since Hawaiian systems can be open looped with less collectors and smaller tanks. It is also interesting to note that Hawaii just recently became the first state to mandate that all new homes in Hawaii will be required to have solar water heaters installed beginning in 2010. So here's a question, who will become the second state?
It should be AZ. There's no excuse for them to keep using NG, Nuke, and Coal to heat water give the amount of sunlight they get. It's absurd. I wonder how much the systems would cost if they were designed in and installed during construction. Seems like the costs would come way down. Anyone have a sense for that?
Arizona certainly seems like it is an appropriate choice as are California and Florida. Interestingly, California had solar hot water systems in the late 1800s until the discoveries of natural gas in the Los Angeles basin during the 1920s and 1930s killed the local solar water heater industry. The Solar Water Heater Company was established in Florida in 1923. By 1941, nearly 60,000 hot water heaters had been sold in Florida where 80% of Miami’s new homes had solar hot water heaters and more than 50 percent of the city used them. Solar water heaters were also used in north Florida, Louisiana and Georgia. At the start of World War II, the government put a freeze on nonmilitary use of copper, stalling out the solar hot water heating market. After the war, the rise in skilled labor and copper prices made the collectors less affordable. Electric prices dropped in the 1950s, making electric water heaters more appealing. Installation and initial cost was also cheaper than solar hot water heaters. The tank was automatic too. Solar water heating was not the same bargain anymore in the United States, especially when oil import limits were allowed to surpass 50 percent. There are still a few of these early collectors in use around Miami and Orlando. A similar scenario happened later in Japan when it began importing oil in the 1960s. The peak year for Japan’s solar hot water sales was 1966. Throughout history, solar energy is popular until abundant sources of fossil fuel become available. Interest in solar energy surged during oil embargoes in 1973-74 and 1979. Today, more than 1.2 million buildings have solar water heating systems in the United States. This doesn’t include 250,000 solar-heated swimming pools. Japan has nearly 1.5 million buildings with solar water heating in Tokyo. In Israel, 30 percent of the buildings use solar-heated water.
I'm just happy that I never even have to learn how to spell "anti-freeze" again... and I've read that New Jersey is another hotbed of solar subsidy. The net cost of Hawaii solar water-heating systems is about $1400 after refunds & tax rebates. That's a bargain-- we built ours out of a used water tank heater & two used collectors plus retail-price copper piping and leftover scrap-metal supports for just under $1000 (our labor was free). The new law is a great idea but the political pissing & moaning was unbelievable. All the military base housing built here in the last decade is 100% solar water, and one Army base housing neighborhood also includes a couple kilowatts of photovoltaic panels on every roof. (The nation's largest PV neighborhood.) Yet statewide only 35% of the homes use solar water. Putting 250 solar water systems into a new-construction neighborhood is probably not much more than $1000/home, even with today's material costs & shipping. However very few Hawaii homeowners are willing to shell out ~$4000 for a solar system, even if they're getting back $2500 within a couple years and will reach payback in under five years. It's not considered part of the home's resale value, either. Don't even get me started on the politics & economics of photovoltaics. At least Wal-Mart has figured it out, putting over 250 KW PV systems on two of their roofs. (Payback is pretty quick at 25 cents/KWHr.) However PV attitudes will change as panel production ramps up and prices come down. Today Hawaii generates about 7% of its electricity from renewables (trash-burning combustion plants, wind, PV, & geothermal) and is expected to reach 20% by 2020. A local startup, Sopogy, just got $35M of state bonds to build a PV farm that'll supply 10% of the state's demand in a few years. Neighbors are paying $400/month electric bills and another $400/month to gas up their SUVs & pickup trucks. I tell them about our $25/month electric bills and that I can't remember what gas costs because I don't fill up the Prius very often. They just shake their heads and change the subject...
And you've hit one very big nail on the head. Resale value. We all know that buyers that see PV, solar or tankless consider it a value or a selling point. However, appraisers won't count it, nor will real estate agents. They say there is "no resale value". And I say Bu!!sh!t. I've got tankless and a PV system and I'll bet I can sell my home faster and for more money than any comperable home in the neighborhood. And probably some in other neighborhoods too. Buyers aren't stupid. I have no idea what the real estate market is gaining by denying the resale value of solar, PV or other energy saving methods.
Bullseye on you B*!!**!* statement. The real estate agents described must be related to the Toyota salesmen that try and steer customers away from the Prius.....operating on concepts that died years ago.
Unless you sell your home to Ed Begley or Bill Nye The Science Guy, I don't know if I'd count on getting anything for PV or tankless. I've done two FSBOs and gone to hundreds of open houses. Solar water heating counts for nothing on Oahu because its net expense is lower than replacing kitchen appliances. PV might attract some attention but most homeowners are blissfully ignorant enough to be fearful of caring for it ("OMG what if it breaks?!?") and they'll pay far more attention to other home features instead of the net-present value of lower utility bills. You have a much higher opinion of buyers than perhaps most are qualified to merit, and I can't ever remember a house sale being facilitated or delayed just because of its utility costs. And even if you come across your dream buyer, they'll notice that no one besides you & them gives PV any resale value and will price their offer accordingly. I've talked with two neighbors whose PV systems were installed by previous owners. They pay no attention to their utility bills and regard the various pieces of equipment as garage obstacles. They're even afraid to touch the stuff, let alone pay someone for its value...
Their loss. Someday VERY soon, utilities will eat everyone's lunch. Those smart enough to recognize alternatives to heat/cool/power their homes (and cars) will evolve, leaving the rest to pi%@ and moan. Actually, that day is a happening TODAY with rising costs using old fuels (spelled OIL-based) really alerting the smart people to go alternative. It's a chain reaction..."you pay how little to power exactly what I do?"..."how can I get on board". It's the same with the Prius. Show people HOW to fish...not just give them the fish.
