Monday, December 13, 2010

Solar Thermal Heating

Solar thermal heating is one of the most cost effective and efficient ways to incorporate the benefits of renewable energy into a building. Because the sun is used to generate heat, the fuel is not only clean, but it is also FREE! That means lower utility bills! Once any higher initial costs of solar system equipment are recovered through avoided electricity costs, the system will only require expenditures for maintenance. Additionally, if a solar heating system is included in the mortgage of a new home, the cost savings and benefits are immediate. It is important to note that equipment and installation costs are significantly defrayed when utilizing federal, state and local incentives and rebates designed to encourage use of energy efficient and renewable energy technologies. (image ref: Caleffi Hydronics)

Solar thermal systems offer a range of applications to reduce energy costs. Solar heating systems are an excellent way to heat swimming pools, a building’s water, and interior space. A typical residential solar water-heating system reduces the need for conventional water heating by about two-thirds. It minimizes the expense of electricity or fossil fuel to heat the water and reduces associated environmental impacts (U.S. Department of Energy).
Solar heating systems are a clean energy technology that not only contribute to the health of the environment, but also protect human health and well-being. They are clean emitting, which means no harmful pollutants such as carbon dioxide, sulfur dioxide, nitrogen oxides, and other wastes are released into the atmosphere. The result is clean air to breathe and a healthy thriving planet for present and future generations.
These benefits all equate to a perfect outcome of lower energy costs, clean environment, improved conditions for human health and welfare, and increased energy security.

Sunday, June 21, 2009

Apples To Oranges ?

With the growing industry of Solar Thermal Products, a lot of products are hitting the market that are not built correctly, efficient, tested, or certified by the SRCC. As much as 60% Federal and State Tax Credits are given in some areas for qualified Solar Thermal Systems. That along would save you several thousand dollars in costs. But the panels must be SRCC rated for the any tax credits.

In your shopping, you will find simple Flat Plat Solar Collectors, or Evacuated Tube Solar Collectors for sale within your local area.  Some Evac Tube panels are sold as Evacuated Tube Collectors but are actually the less efficient Evacuated U-Tube collectors and not Evacuated “Heat-Pipe” Solar Collectors. 

When comparing Flat Panels to Evacuated Tube “heat pipe” panels, your earthly solar location is important. Flat panels are less efficient in cold weather in areas with temps near and below freezing. Be aware of your needs.

It is important that you ask for SRCC certification. Some lower quality Solar Thermal Panels are out there. Look at the specific panel SRCC heat rating on their certificate and compare heat output. Our 30 tube panel is rated for over 46,000 Btu on a sunny day, for only 30 Sq Ft of Solar Aperture. Your Federal and State Tax Credits credits to you depend on the certification.

Our Evacuated Tube Solar Thermal Panels and Flat Plate Panels have met all the SRCC requirements and rated to be installed  as a quality product able to produce extreme amounts of Solar Energy for our customers, reduce their carbon footprints, and reduce their fossil fuel expenses.
Back to the basics… compare apples to oranges when picking solar thermal panels. Get expert advice and design.

Saturday, May 23, 2009

What about Evacuated Tubes vs. Flat Panels vs. Thermosyphon Panels vs. U-Pipes?

Evac Tubes are great for hot summer days to sub zero temperatures, and can go on the ground, slanted against a house wall, or on the roof. They are not affected by wind or outside air temp and produce heat with all sun angles 360 degrees.
Flat Panels are great for very hot to nearnfreezing temperatures, and can be placed anywhere also. But, they are limited to southern exposure and their efficiency is reduced in freezing areas or cold windy areas.
It all depends on your location:
In the sunny middle of the country, one of our Solar Evacuated Tube Panels will produce an average of 9,000,000 Btus per year, or 290,000 Btu's per year per sq ft at an initial panel cost of $38 per Sq Ft. On a bright winter day they will produce an average of 1,400 Btu's per Sq Ft per day.
In the sunny middle of the country, one Sq Ft of our Solar Flat Panels will produce an average of 294,000 Btu's per year at an initial panel cost of $32 per Sq Ft. On a bright Fall or Spring day they will produce 1,418 Btu's per Sq Ft per day. If you are in an area where near or below freezing temps are normal for the heating months, then Solar Flat Panels will not produce enough energy to match the Evacuated tubes. Solar Evacuated Tubes would be the proper and efficient Solar Panels for that climate.

Flat Panels are more efficient in warmer climates than Evacuated Tube Panels, as Flat Panels are affected by outside air temp and cold wind. Evacuated Tube Panels are more efficient in warm to sub-freezing climates, as they are not affected by outside air temperature or cold wind, and absorb available sunlight from 360 degrees.

Thermosyphon Panels are very simple and should be placed on the ground near the house. They are great for areas with freezing to hot temperatures and used with an open loop, i.e. city, cistern or well water is heated directly in the panels and goes right into your Domestic Hot Water Tank for house use.
U-Pipes use evacuated tube technology but can be placed flat, sideways or vertical... as against a balcony railing or on a south house wall.

Can I install these solar panels myself?

Sure, no problem. It takes about 90 minutes to put together one of our panels. If it sits in the yard, it is not a complicated installation. Click here to see some drawings. You would have to be handy with sweating copper and some minor electrical work. You should have an electrician or plumber inspect your work if you have any doubts. If they go on your roof, then I would recommend a roofing expert and plumber to get the panels up there and plumbed to your equipment room. There is still a 3 year product warranty if you install our panels, or 10 years if we do it, or one of our installers in your area. Expected life span of our panels are 25-35 years.
A  $ 4,000 investment in Solar Thermal “ heat pipe” Evacuated Tubes will return over $40,000 in system savings of the expected system lifespan, considering inflation of fossil fuels.

Is solar water heating a viable alternative to gas or electric heating?

Solar should not be seen as an alternative to heat sources, but rather a supplement. Solar cannot totally replace the need for these sources, as there are times when sunlight is limited. However, over the course of a year, a correctly sized solar system can provide 80-90% of your household hot water needs, or 50% of your house heating needs.

A family of 3 can save about $600 per year on just hot water needs. Over 10 Years, with an average fossil fuel price increase of 10%--( it has gone up 100% in the last 7 years), you would have a payback in about 5 years, and basically savings for the next 30 years. Payback for commercial buildings in 2-3 years. The price of your house will go up more than the initial investment, many times. The average out of pocket cost for a complete DHW solar system, for a family of 3 is--- $ 3,500- $ 4,800 depending on your needs. Payback in 5-8 years on the average.

How long will it take to recoup my investment?

Our Solar Thermal Panels are much more affordable than most other Solar Water Heaters available on the market today. For a household of 4, it may not be much more than the cost of a new gas or electric heating system. Depending on your location, solar insolation, weather and current hot water use, the annual gas, oil, or electric savings will vary. However, in a normal household that spends 30% of its annual electric bill on water heating, the full cost of the purchase may be recouped as quickly as 4-5 years. We can design your entire system for your use if desired, and that includes a $300 credit towards the purchase of any of our Evacuated Tube Panels. There is little doubt that you will save tens of thousands of dollars, or more, over the lifetime of our Solar Water Heater, Solar House Heating systems.

For a savings of just $600 per year,  an average family of four with a complete installation cost of $4,700:
Payback Period Calculation Chart:
Year Annual Fuel Savings(with 10% fossil fuel price increases)
Remaining System Cost
Year 1 $600.00 $4,108.00
Year 2 $660.00 $3,448.00
Year3 $726.00 $2,722.00
Year 4 $798.00 $1,924.00
Year 5
Year 6

After the 6th year, the original $600 you were saving is now over $ 1,000 per year saved on your DHW heating bills.

You will have doubled your original investment in year 9.

In 16 years you will have saved over $ 17,000.

What happens if one of my Evacuated Tubes is broken?

A non-event.  This is a simple fix. The tubes will not break for weather issues, but a baseball, rock, or falling meteor will win the battle. A broken tube will not affect the working panel other than reduce the complete Btu panel output by 243 Btu’s.  When ready, you simply slide the old tube out and slide in the new one. About a $ 25 cost. 
The panels’s working heat transfer fluid continues to operate normally with these “Heat Pipe” Panels. With our SRCC and international Keymark certification and ratings, our solar evacuated tubes were tested over a 30 day period with extreme heating of over 450 F, shock tested, stress tested, pressure tested, and impact tested. Various size ball bearings were dropped from 32 feet and did not break the glass tubes...laying flat.

Will water be heated on a cloudy day?

Yes. Although the output of the collector will be reduced on cloudy days, they are still able to provide a significant amount of heating. It is all based and engineered with your location and SOLAR INSOLATION. Basically, the amount of available sunlight at your piece of the earth over a 10 year period. This is what we use to design and engineer your Solar Thermal System. See our design web site.
The cloudier the day, the more your backup gas, oil, or electric heater will be used to maintain the proper temperature in your hot water. This ensures that you never run out of hot water, regardless of your weather conditions. Snow does not stop the use of your panels, as it still gets solar radiation through the snow.
During a recent visit in April to one of our 6 year old Colorado  solar systems, we covered the Evacuated Tube Solar Panels with blue tarps while we turned off the circulator pump to do some work on the DHW in the house. It was 45 degrees outside but sunny. At the end of the day, the Heat Transfer Fluid in the panels had heated up to 110 degrees F... while covered up with a blue tarp.

What is a drain-back system?

It is one of the least expensive setups to use as part of the operating system for your solar thermal. The DrainBack system allows all the fluid in the panels to drain back (with gravity) to a holding tank when the system is not being used such as at night, or when the panels are producing more heat than you need.
There are two major concepts to understand when comparing the different types of Solar Water Heating Systems:
Open-Loop Systems
A system in which the domestic hot water, which comes directly out of the shower-heads and sink faucets, is itself directly heated in the solar collector.
Closed-Loop Systems (including Drainback)
A system in which a heat transfer fluid is heated by the collector, and the heat is passed to the domestic water through a heat exchanger.
Passive System
Uses no mechanical parts to circulate the water through the heating system.
Active System
Uses moving parts such as pumps, valves or controls to circulate water through the heating system.
1. Thermosyphon System – Easy installation, passive operation
2. Open-Loop Direct – Lightweight, installation
3. Pressurized Glycol – Lightweight, overheat and freeze tolerant
4. Closed Loop Drainback – Lightweight, freeze tolerant

Will the Solar Thermal Collector be a fire hazard during hot/dry weather?

Not at all. The hot solar thermal fluid is contained within the copper lines. Each component of our Solar Collectors are high-temperature rated and non-flammable, so even during periods of strong sunlight with the pumps off (stagnation) such as in a drainback system, the system will be no fire threat. The Evac Tubes are cold to the touch even while they are producing over 150 F water to your house heating and/or DHW tank. The majority of components are stainless steel, aluminum glass or glass wool. The manifold outlet will be fitted with a pressure/temperature relieve valve, which will prevent the fluid temperature from exceeding it limits. 

Can Solar Thermal Collectors heat water to a high-enough temperature?

It all depends on the solar insolation (sunlight) for that day.The Evacuated tubes set at the proper angle, based on your needs, produce more heat as the sun angle lowers with the season. Basically, as the outside air temp rises, the panels produce less heat as the sun is at a higher angle. As seasonal temps get colder, the panels get hotter and produce more heat for your domestic hot water needs and house heating. The system would be designed to deliver a daily DHW storage tank temperature rise of 25-30 C/35-55 F. With most designs, this heat is stored in a tank, then with a heat exchanger, goes into your existing DHW tank and/or house heating such as baseboard or in-floor hydronics, hot tub or swimming pool.

What maintenance is required for Solar Collectors?

Under normal conditions and circumstances, no maintenance of the system is required for several years. The life expectancy of the panels is over 25 years but the pumps, glycol water mix, and some valves will have to be changed at the end of their life time just like your present water heating system in use. Plan on a budget of $40 per year for these issues. The first repairs needed will not be for the solar panels, just the mechanical equipment in about 10-15 years.

Can Solar Water Heaters be used for large scale hot water production?

Yes. Our Solar Thermal Collectors can be added in series or parallel to provide additional water heating capacity as needed. This is particularly effective for schools, apartments, resorts, hotels, offices, and other larger buildings. In reality, there is no limit to the amount of hot water our Solar Collectors can produce – simply increase the number of collectors as the hot water demand increases.

In a nut-shell, so to speak, mid-country on the average, one 30 tube panel ($1,500 ) will produce about $250-$300 in energy savings per year and sufficient for a family of 3 for DHW. For additional house heating, you might need up to 4 panels. The savings would then then be at least $ 1,000 per year. 
Regardless of the size of the system, commercial or residential, the payback will always be 5-8 years, good for at least 25-35 years. Please visit our system design web site to get started.  

Can I heat my swimming pool or spa with solar panels?

YES--- Solar can be used efficiently to supplement the pool or hot tub water with a heat exchanger. Simply put, when the Sun comes out, the panels turn on, and the heat passes thru a heat exchanger with your pool pump water flowing. The pool temp will rise slowly based on many situations such as wind, air temp...etc. 

There is a lot of heat loss from the pool or tub water surface but our Solar Thermal “heat pipe” Evacuated Tube Panels will produce heat reliably and daily to reduce your pool/spa heating fuels. 

Here is a project with pool heating, DHW, and floor heat with two 25 tube panels. Savings of 200 Therms per year, about $550. Project cost $4,200
Installed Collector Power: 16.38 kBtu/hr
Installed Gross Solar Surface Area: 73.84 sq.ft
Collector Surface Area Irradiation (Active Surface): 24.12 MBtu 598.74 kBtu/sq.ft
Energy Produced by Collectors: 15.25 MBtu 378.58 kBtu/sq.ft
Energy Produced by Collector Loop: 13.45 MBtu 333.84 kBtu/sq.ft
DHW Heating Energy Supply: 209.93 kBtu
Space Heating Energy Supply: 10.01 MBtu
Solar Contribution to DHW: 2857.32 kBtu
Solar Contribution to Heating: 5.64 MBtu
Energy Swimming Pool Solar System: 4.95 MBtu
Energy from Auxiliary Heating: 34.52 MBtu
Natural Gas (H) Savings: 19,570 cu.ft
Natural Gas (H) Savings: 197.75 therm
CO2 Emissions Avoided: 2,583.53 lbs
DHW Solar Fraction: 63.1 %
Swimming Pool Solar Fraction: 14.8 %
Total Solar Fraction: 28.0 %
System Efficiency: 55.8 %