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Solar Hot Water Systems
From WikiVerde
Solar hot water systems, using solar energy to heat water are getting increasingly popular these days considering they are both energy and cost efficient. This is so because the utility power consumption during the process of heating water is significantly reduced while using solar hot water systems.
The more water is heated by the sun, the less need for conventional sources of energy like electricity to heat the water. Thus you save money and you save energy. The end result is good news for the environment in general.
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Passive Solar Hot Water Systems
Passive solar hot water heating is taking a container or a bucket that has been painted black and filling it with water and then putting it out in the sunlight. If there is enough sunlight then in a few hours you will have on offer, hot water, compliments of the sun.
Passive solar water heating could be called a primitive form of harnessing solar energy for the purpose of heating water. There are also developments that have lent a bit of sophistication to this process. For example, "batch" collectors which are tanks that are placed inside an insulated metal box. It is is then covered with a material that attracts sunlight like a solar glass or a glazing material.
There are various other passive solar hot water systems available on the market, like the thermo-siphon systems that resemble active systems as they have solar panels.
Active Solar Hot Water Systems
One of the primary components of active solar hot water systems are flat plate solar collectors. During the process of heating, fluid flows continuously through the collector plates.
Active solar hot water systems are available in three distinct designs. However, there are various other designs, modifications, and variations that are available on the market which utilize facets like vacuum tubes, concentrating mirrors, and parabolic troughs that accomplish the same result as do the basic design of solar hot water systems. In terms of performance and cost efficiency, the more popular of solar hot water heating systems are open loop systems, closed loop systems, and drain back systems.
Open Loop Systems
There is direct heating of water in open loop systems. Water is circulated through the solar collectors using a small pump that has been mounted on a tank that stores water. A differential thermostat controller activates the solar pump, and it is configured to sense the availability of heat in the solar collectors. The hot water heater and the solar storage tank are connected to each other. Preheated solar water is fed into electric or gas hot water heaters when hot water is used.
With regards to an open loop solar hot water system, the maintenance costs are quite a bit less as compared with other systems. This is because there is no use for aspects like heat exchangers or special fluids. Moreover, the installation is cheap and the efficiency is much higher than various other designs.
Closed Loop Solar Hot Water Systems
Unlike open loop systems, closed loop systems, prefer the use of heat exchangers that are used for the circulation of heat-transfer fluids throughout the feed pipes and panels. The name closed loop comes from the fact that external atmosphere is not allowed to affect the solar exchange fluid. The heat exchanger isolates it from the potable water.
Solar fluid is heated and pumped through to the solar collectors. Heat exchangers made of copper or stainless steel are located near the solar storage tank, and the hot solar fluid passes through them. The potable water that is stored in the solar storage tank imbibes the heat and thus gets heated. One of the most important advantages of closed loop systems is the fact that the heat exchanged fluids can withstand the lowest of temperatures, and thus can be operated even in freezing weather.
In terms of operating costs, these heating systems are the best choice, and they are also reliable and stable.
Drainback Solar Hot Water System
The best of open and closed loop solar hot water systems is brought together in the drainback hot water system. A closed loop system type of structure is present between the drainback tank and the solar thermal collector, which is used for the heating of water. The structure of the drainback system that closely resembles the open loop hot water system lies between the regular water tank and the pre-heat tank.
The active components of drainback solar hot water systems are:
A water tank
A small heat–transfer fluid tank
Array of solar panels
A heat transfer system
The best part about such a system is that it requires minimal maintenance and can run for years without intervention of any form. They do not cause any damage, or at least no significant damage in case they fail to function in freezing weather. Moreover, facets such as the heat–transfer fluid need not be changed frequently, which again lends itself to cost efficiency.
Advantages of Solar Water Systems
Solar water heater systems are becoming more common in households across the world. They can work in any climate and are much cheaper than the conventional water heater in the long run. In many countries like the United States you might receive a state refund and tax credits are offered on the cost of the installation of a solar water heater. This is in a bid to popularize the use of environmentally-friendly appliances.
Energy and cost efficiency coupled with reliability and stability is truly a great bargain for customers. The only thing that you must be wary of is to purchase solar hot water systems that confirm to certain established standards and requirements.
So use solar hot water systems to not only make a financial difference to your life but also to make a difference to the environment in general. They have emerged as a viable choice when it comes to an option for a product that seeks to minimize environmental pollution.
References
http://en.wikipedia.org/wiki/Solar_hot_water http://www.azsolarcenter.com/technology/solarh20.html
