Solar Attic Ventilation

Jun 29
2011

 

One of the great things about a solar attic fan is that they can be installed anywhere, anytime making it a superb DIY solar energy project. You don’t need any permits or technician labor to have it installed. As it runs on solar energy, it’s logical that your solar power attic fan will only turn on during the day time. Interestingly, this is a great thing, because in hotter places the day time is when you really need the ventilation to work at its peak.

Finding the Right Solar Attic Fan Location

There are two popular places where people tend to place this unit: roof or the gable. The choice is really determined by the kind of requirements you have. If you want decent ventilation but also want to avoid rain from seeping into the house through cracks or openings, then you must have the vent in the gable. However, if you live in a dry place and peak ventilation is all you care about the roof is the best place as it receives maximum sunlight.

Analyzing Your Ventilation Scheme

Now you’ll need to do a little investigative do diligence to get the most efficiency from your solar fan because it’s best to place your solar power attic fan in a location where it will be the most effective. For this, you need to study your ventilation scheme and understand your home’s air movements. Based on your analysis you’ll find the sweet spot for your solar fan.

Enhancing Your Natural Ventilation Scheme

OK so let’s say you can’t find any vents and you need to find a good place to put it or the vents seem to be in the wrong spot (believe me this can happen). Remember we’re still talking “natural ventilation” here and have not yet gotten to the fan. The best way around this is to redesign or modify your natural vent scheme and add a few more vents. The best place to add these vents is near the roof to help take advantage of the chimney effect. This is easy to do just by purchasing the necessary hardware from the local stores.

Finding the Right Installation Location

As you may have guessed picking the best location for your solar power attic fan is based on the natural air movement analysis. As discussed you may find that there are already passive vents installed and they’ll be closer to the roof to push the air outwards. If you can fit your solar attic fan into one of these you’d have an ideal install. Typically, for such a setup you would not need to install a new vent. The only challenge though would be to find a fan that fits that vent.

Keep in mind that you must locate the solar attic fan downwind to ensure the ventilation is uniform throughout the attic. Also, sunlight exposure for your fan’s home solar power panel is a major factor in finding the best location.

Picking the Right Type of Solar Attic Fan

When it comes to fans you have two choices for this little DIY solar energy project: the complex distributed system and the simpler single unit system. Total cost for a one-piece unit (single unit system) is around $300. One-piece attic vent fans are simple to install. With single unit solar fans you need not play around with your attic ventilation system. If you can’t fit the fan into an existing passive vent then you’ll have to cut a hole in the roof, pull the shingles back, slide the unit up under the shingles, and install the fan in the hole. Seal the opening and carry out proper weather proofing and you’re all setup.

Of course while installing the fan you need to ensure that you avoid the trusses. The best solution to this is to locate a good spot from the attic and drill the holes from inside out. This way you will know exactly where to place the fan when you go on the roof. The only problem with the one piece systems is that your home solar power panel is integrated into the fan. So the best location on the roof may not get the most sunlight. Without sufficient sunlight, the fan is not of much use. Then you’ll need to look at the distributed solution.

This means after you buy your solar panel house attic fan it will have two sections. One section would have the actual fan and the other section would have your home solar power panel to power the fan. You would need to remotely install the panel to take advantage of the most sunlight.

Heating Your Pool With Solar Power

Jun 17
2011

 

When people hear “water heater”, they don’t think about a solar power pool heaterwhat really comes to mind is their household water supply. But the terms solar power water heaters and solar energy water heater can also apply to swimming pools. As well as terminology, many solar power pool heater characteristics also apply to solar power water heaters used for the household water supply. The technologies and desired effect are the same in some cases.

For instance, you will find digital ICS (Integral Collector Storage) systems employed for both jobs in some but not all instances. While most solar power pool heater systems are basically the same, the way heat is collected, and the very collectors themselves, can be strikingly different. However, there are some commonalities you should remember regarding any pool heating collector you buy.

Understand the warranty and repair costs and liability of any solar energy water heater or collector BEFORE you buy. You'll need to know if you or the manufacturer will make repairs if the need should arise. And also be aware that you can't clean out mineral deposits from collectors once they build up. Hard water is “harder” on your system than soft, and the only way to clean out your system is with water treatment chemicals from a pool supply store. To save yourself these headaches, you can also add some type of filtration system to your water source before it reaches the collector. Let's take a look at some common solar collectors that are generally used to power a solar power pool heater.

Easily the least technical solar energy water heater collector on the market, and the least expensive, is a simple portable grid. This collector is made of flexible, molded plastic, and can be laid anywhere. Placed on your roof or anywhere on the ground that has optimal sun, a common size is 2' x 16', but different sized strips abound. They simply connect to your current pool pump and you are harnessing solar power.

A batch collector is the next technologically evolved collector. This solar power pool heater is simply a tub or tank mounted in the sun. When the water heats up, it can heat your pool. If you want to ramp up the heat in low-sunshine areas, paint the tank black, and add reflectors to maximize heat production. You can often double the heat production of this particular solar power water heater this way. Better yet is enclosing a black tank to prevent heat loss that would escape from a non-enclosed unit, and adding glazed windows to enhance the sun's natural powers. Simple to build and efficient without pumps and control panels, they are ideal for remote areas. 55 gallon drums make excellent low-cost, low-tech collectors.

Flat-plate solar collectors are rectangular boxes with an aluminum or copper “flat plate” collector painted black for maximum heat absorption and mounted on the bottom of the box. Several rows of copper tubes in contact with the collector plate are used to circulate and heat the fluid inside them. As sunlight warms the plate, this heat is passed to the pipes, and then to the water supply. The whole box is then covered with a plastic or low-iron silicon glass, or glaze, to minimize heat loss. This produces an incredibly efficient heat collector. There no moving parts, and the glaze keeps freezing from occurring. The only maintenance for this type of solar power pool heater is keeping the glaze or window free of debris.

They shed snow rapidly from the warmth inside, and don't mind wind and cold that causes other collectors some freezing issues. And if you add large diameter tubes from an ICS collector mentioned above, cold weather damage is almost non-existent. These are excellent solar power water heater collectors when you prefer to spread the weight out over your entire roof, because they can be used in parallel.

The last type of solar power pool heater collectors are evacuated tube collectors. Evacuated tube solar collectors are absolutely unaffected by freezing air temperatures and are expensive, both of these characteristics being due to their construction. They also perform great in wet, windy environs that cool other collectors down. This is due to their excellent insulating properties, another characteristic of their design.

Evacuated tube collectors comprise a row of hollow, glass vacuum tubes (envelopes). Copper rods or fluid-filled tubes (much like a direct, batch-type collector) are contained inside these vacuum tubes. These copper rods then connect to a huge copper tube in the “header”, which is enclosed and through which water or antifreeze flows. The copper rods heat up from sunlight, move this heat to the header, and from there into the fluid. Reflectors can be planted in the back of and around these tubes, increasing heat absorption.

This solar power pool heater collector system is so well insulated that the rods can get up to 250 degrees fahrenheit, and the envelopes are still cool to the touch. They also perform better than most on cloudy days, and on sunny days, the perpendicular placement of the tubes draws heat the maximum amount of time possible during the sunlight hours. However, this type of solar energy water heater does not shed snow very well, and are very fragile. Attempting to manually brush off snow or ice can easily damage or break them. Once a seal is broken, the vacuum is compromised. But a single element can be easily replaced, and the system's integrity restored. This is not the case with other collectors, where the entire collector system must be swapped out.

Solar power water heater collector technology varies in direct proportion with cost. Taking into account the above factors, you can easily choose the right solar power pool heater system to fit your needs and physical and meteorological circumstances.